Steven Craig - Academia.edu (original) (raw)

Papers by Steven Craig

Research paper thumbnail of Aquanomics: The application of genomic technologies to aquaculture

12.1 Introduction 12.2 The current state of genomic play 12.3 Homology analysis of zebrafish prob... more 12.1 Introduction 12.2 The current state of genomic play 12.3 Homology analysis of zebrafish probe sequences against cichlid genomic resources 12.4 Dietary manipulation of intestinal gene expression 12.5 Conclusion Keywords References

Research paper thumbnail of Use of Microbial Flocs Generated from Tilapia Effluent as a Nutritional Supplement for Shrimp, Litopenaeus vannamei, in Recirculating Aquaculture Systems

Journal of the World Aquaculture Society, 2008

Recovering nutrients in a fish effluent to be used as a supplemental feed for shrimp culture coul... more Recovering nutrients in a fish effluent to be used as a supplemental feed for shrimp culture could ease constraints (e.g., environmental issues and high production cost) that have limited the US shrimp farming industry in the past. In this study under laboratory scale conditions, fish effluent was collected from a commercial tilapia farm and nutrients from the waste stream were offered as supplemental feed as either (1) untreated solids from tilapia effluent or (2) microbial flocs generated from the biological treatment of the effluent by reducing soluble chemical oxygen demand .80%. The first feeding trial demonstrated that microbial flocs contributed significantly (P , 0.05) to overall growth while untreated solids did not. Moreover, microbial flocs were larger and contained higher levels (P , 0.05) of protein. The second feeding trial investigated different feeding rates of commercial diets with and without microbial floc supplementation. Weekly measurements of mass and specific growth rates demonstrated that microbial flocs significantly (P , 0.05) contributed to shrimp performance. Weekly food conversion ratios were also reported. Water quality in shrimp systems during both studies was within safe levels, and no differences (P. 0.05) between treatments were observed for dissolved oxygen, nitrate-nitrogen, nitrite-nitrogen, pH, salinity, total ammonia nitrogen, and temperature.

Research paper thumbnail of Chemical, Physical and Sensorial Differences in Farmed Southern Flounder ( Paralichthys lethostigma ) Fed Commercial or Crab Meal-Supplemented Diets

Journal of Aquatic Food Product Technology, 2006

ABSTRACT A 12-week feeding trial was conducted to determine the effects of a commercial and a cra... more ABSTRACT A 12-week feeding trial was conducted to determine the effects of a commercial and a crab meal-supplemented diet on sensory properties of southern flounder (Paralichthys lethostigma). Proximate analysis, color, fatty acid composition, texture and sensory analyses were performed on the fillets. A significant difference in flavor was found between fillets fed on a commercial or a crab-meal supplemented diet. No significant difference was found between the fish fillets when comparing fat, protein, fiber content and texture. However, ...

Research paper thumbnail of Efficacy of Concentrated Algal Paste During Greenwater Phase of Cobia Larviculture

Journal of Applied Aquaculture, 2008

The purpose of this study was to determine if concentrated algal paste could effectively replace ... more The purpose of this study was to determine if concentrated algal paste could effectively replace live algae during the greenwater stage of cobia fingerling production without negative impact upon larval growth or survival. Mean cobia survival per tank from 2 dph through post weaning at 28 dph for the live algae treatment was 24.44 ± 2.43% (mean ± SD) as

Research paper thumbnail of Performance of Advanced Juvenile Cobia,Rachycentron canadum, Reared Under Different Thermal Regimes: Evidence for Compensatory Growth and a Method for Cold Banking

Journal of Applied Aquaculture, 2007

ABSTRACT Two trials were undertaken to examine the growth response of juvenile cobia, Rachycentro... more ABSTRACT Two trials were undertaken to examine the growth response of juvenile cobia, Rachycentron canadum, at varying temperatures. The initial trial was conducted to determine the effect of various temperatures (18, 23, and 29° C) on weight gain and feed efficiency. The second trial investigated the effect of elevating water temperature in which fish maintained at 18° C and 23° C to a temperature close to their optimum (29° C). The latter study was undertaken in order to determine the effect of thermal shifts upon ...

Research paper thumbnail of Taurine supplementation to alternative dietary proteins used in fish meal replacement enhances growth of juvenile cobia (Rachycentron canadum)

Aquaculture, 2007

Two separate 8 week feeding trials were conducted to examine the impacts of fish meal replacement... more Two separate 8 week feeding trials were conducted to examine the impacts of fish meal replacement with an organically certifiable yeast-based protein source with and without supplementation of methionine, tryptophan, and taurine to diets for juvenile cobia. In the first trial, diets were formulated to contain 41% crude protein and 13% lipid, and a yeast-based protein replaced fish meal at 50 and 75% of dietary protein with and without supplemental taurine at 0.5 g/100 g dry diet. The control diet contained 100% herring fish meal. Methionine and tryptophan were added to all diets except the control to resemble the amino acid profile of fish meal. Results from this study indicated that fish fed diets supplemented with taurine exhibited significantly higher weight gain and better feed efficiencies than all other fish. Diet significantly impacted biological indices such as muscle ratio (MR), visceral somatic index (VSI), and hepatosomatic index (HSI). The 75% yeast-based protein diet without taurine returned the lowest MR values and the highest VSI and HSI values. In the second trial, diets were formulated to contain 43% crude protein and 11% lipid, with the control diet containing 100% herring fish meal and the same yeast-based protein replacing fish meal at 50, 75, and 100% of dietary protein. All diets except the control were supplemented with taurine at 0.5 g/100 g dry diet. Results from this study indicated that increasing amount of yeast-based protein led to decreased weight gains and feed efficiencies regardless of taurine supplementation. However, weight gain and feed efficiencies did increase when compared to a previous study [Lunger, A.N., McLean, E., Craig, S.R., 2007. The effects of organic protein supplementation upon growth, feed conversion and texture quality parameters in juvenile cobia (Rachycentron canadum). Aquaculture 264, 342-352] using identical diet formulations except for taurine supplementation. MR values tended to decrease while VSI and HSI values tended to increase with increasing fish meal replacement. It is obvious from the results from both of the present studies that taurine supplementation does have a significant impact on growth and feed efficiency of juvenile cobia when they are fed diets containing high levels of plant-based proteins as

Research paper thumbnail of The effects of organic protein supplementation upon growth, feed conversion and texture quality parameters of juvenile cobia (Rachycentron canadum)

Aquaculture, 2007

An eight week feeding trial was conducted to examine the impacts of organically certifiable alter... more An eight week feeding trial was conducted to examine the impacts of organically certifiable alternate protein sources on growth, feed efficiency, biological indices, fillet proximate composition and fillet quality in juvenile cobia. Diets were formulated to be isonitrogenous and isocaloric. The control diet provided 45% crude protein from Special Select® menhaden fish meal and 10% total lipid. The remaining diets were formulated with 25 and 40% inclusion of NuPro® (an organically certified yeast-derived protein source), and 40% inclusion of organically certified soybean meal, soybean isolate, or hemp seed meal. Two additional diets were formulated to contain a mixture of all organic protein sources at 23% with 8% fish meal or 25% and no fish meal. Diets were fed to triplicate groups of juvenile cobia (initial weight 10 g/fish) in 300 L circular tanks connected as part of a recirculating aquaculture system. Weight gain ranged from 167 to 1138% increase from initial weight and was similar for all fish fed diets containing 40% of any given alternate protein source. Fish fed the blended diet with 8% fish meal exhibited significantly lower weight gain, SGR, and FE ratio values than all other fish. Cobia fed the diet without any fish meal did not survive to the end of the study. Biological indices such as muscle ratio (MR), visceral somatic index (VSI), and packed cell volume (PCV) were all similar between fish fed the control diet and those fed diets with up to 40% alternate protein. Fish fed the diet with only 8% fish meal had significantly lower MR, PCV, and plasma protein, and significantly higher VSI. All fish exhibited similar fillet proximate composition for protein, lipid, dry matter, and ash except for those fed the diet containing 8% fish meal. Alternate protein source did appear to impact the fillet texture of cobia. Generally speaking, plant protein sources returned higher textural characteristics than the fish meal control. At all time points and all texture parameters, cobia fed the diet containing hemp seed meal returned the highest values except for distance to rupture in the final time point. Results indicate that up to 40% fish meal protein can be replaced by any of the organically certifiable alternate proteins that were used in this study without detrimental impacts to weight gain, feed efficiency, biological indices, or fillet composition in juvenile cobia. Our results also suggest that alternate proteins have differential effects upon final product quality, which may have implications in terms of cobia processing and development of industrial products.

Research paper thumbnail of Dietary mannan oligosaccharide enhances salinity tolerance and gut development of larval cobia

Aquaculture, 2008

The potential beneficial effects of supplementing live feeds with mannan oligosaccharide (MOS; Bi... more The potential beneficial effects of supplementing live feeds with mannan oligosaccharide (MOS; BioMos®) upon cobia Rachycentron canadum larval performance were examined. Characteristics of fish examined included survival to weaning, growth, ability to withstand osmotic stress and the degree of development of the brush border of the intestine. Live feeds included rotifers (Brachionus plicatilis) and Artemia which were enriched for 24 h with a commercial enrichment media alone or in combination with 0.2% (dry weight basis) MOS. Salinity challenges were performed at 6 days post-hatch (dph) and at 7, 13, and 14 dph (0 and 65 g L − 1 for 6 dph; 0 and 55 − 1 7+ dph) corresponding to transitions in feeding, to examine the ability of larval cobia to survive stress. Differences (P b 0.05) in survival, favoring cobia receiving MOS-supplemented feeds were discerned at 6 and 7 days post-hatch (dph) when fish were challenged at 0 g L − 1 and at 13 dph when challenged with 55 g L − 1 salinity water. Electron microscopy of the mid-intestine of developing larvae revealed that MOS-supplemented diets enhanced (P b 0.05) the height of microvilli while reducing (P b 0.05) the occurrence and size of supranuclear vacuoles. Supplementation of diets with MOS could assist cobia larvae in maintaining allostasis especially when reared at sub-optimal salinities.

Research paper thumbnail of Use of soy protein concentrate and novel ingredients in the total elimination of fish meal and fish oil in diets for juvenile cobia, Rachycentron canadum

Aquaculture, 2010

Achieving true sustainability in fish farming requires the replacement of most of the fish meal a... more Achieving true sustainability in fish farming requires the replacement of most of the fish meal and fish oil utilized as feedstuffs. The present experiment reports 2 feeding trials that resulted in the total replacement of fish meal and fish oil in juvenile cobia (Rachycentron canadum). The first trial was conceived as a 2 × 3 factorial design with three levels of fish meal replacement (FMR; 50, 75 and 100% of dietary protein) by soy protein concentrate (SPC), and two levels of mannan oligosaccharide (MOS) supplementation (0 or 0.3% of the diet). Since MOS has been reported to promote gut health and integrity, it was included in order to verify whether it would ease high levels of FMR. Lipids were supplied by menhaden oil. In the second feeding trial, fish meal was replaced by various combinations of SPC and soybean meal, again with or without MOS supplementation. In addition, some diets were supplemented with purified amino acids. Lipids were supplied by fish oil. A final diet (NOFM) was formulated using SPC, a marine worm meal, a nucleotide-rich yeast extract protein source, and MOS. In this last diet, lipids were supplied with a mix of soy oil and a DHArich algal meal, thereby completely eliminating both fish meal and fish oil. Over both feeding trials, juvenile cobia consistently exhibited excellent performance at 75% FMR and less. MOS did not have a significant effect, although a beneficial trend was observed in the first trial at 100% FMR. In the second trial, the fish fed the NOFM diet exhibited one of the best weight gains and feed efficiencies, with no mortality and no impact on muscle and liver composition. This result illustrates the crucial importance of the selection of feedstuffs for FMR and fish oil, since the NOFM diet did not receive amino acid supplementation. While this represents the first successful elimination of fish meal and fish oil in aquafeeds for cobia, the consistent, successful replacement of 94% of the fish meal in the other diets is actually more promising to the future as they solely utilized commodities traded (soy products) as replacement sources, which is the only road to true environmental and economical sustainability for the aquaculture industry.

Research paper thumbnail of Do fish enhance tank mixing?

Aquaculture, 2005

The design of fish rearing tanks represents a critical stage in the development of optimal aquacu... more The design of fish rearing tanks represents a critical stage in the development of optimal aquaculture systems, especially in the context of recirculating systems. Poor hydrodynamics can compromise water quality, waste management and the physiology and behaviour of fish, and thence, production potential and operational profitability. The hydrodynamic performance of tanks, therefore, represents an important parameter during the tank design process. Because there are significant complexities in combining the rigid principles of hydrodynamics with the stochastic behaviour of fish, however, most data upon tank hydrokinetics has been derived using tanks void of fish. Clearly, the presence of randomly moving objects, such as fish, in a water column will influence not only tank volumes by displacing water, but due to their activity, water dynamics and associated in-tank processes. In order to determine the impact of fish presence upon tank hydrodynamics, Rhodamine fluorometry was employed to examine mixing within a recirculating aquaculture system. Two different methods were compared, traditional, outlet-based measurements and a technique that employed in-tank data acquisition. Circular tanks were employed during data collection either in the presence or absence of experimental fish-red drum Sciaenops ocellatus (n =36; 5 kg total wet wt); and at two flow rates. Irrespective of flow rate, the presence of fish dramatically enhanced the mixing process (P b 0.001), with mixing times in tanks with fish being one-third that for tanks without animals. In-tank dispersion coefficients and dispersion numbers also differed (P b 0.001) in the presence of fish, irrespective of flow. Presence or absence of fish had no effect upon hydraulic residence or circulation times. Unlike measurements at the outlet, in-tank observations were more able to isolate the effects of stochastic, fish-induced mixing, from deterministic, hydrodynamic mixing.

Research paper thumbnail of Juvenile cobia (Rachycentron canadum) can utilize a wide range of protein and lipid levels without impacts on production characteristics

Aquaculture, 2006

Two, 6 week feeding trials were conducted to evaluate the impacts of protein and lipid on weight ... more Two, 6 week feeding trials were conducted to evaluate the impacts of protein and lipid on weight gain, feed efficiency ratio values and biological indices of juvenile cobia (Rachycentron canadum). Utilizing a 2 × 3 factorial design, experimental diets containing two levels of crude protein (CP; 40 and 50%) and three levels of lipid (6, 12 and 18%), providing 14.4, 15.1 and 16.6 kJ available energy/g dry diet (calculated), respectively, were formulated for use in both feeding trials. In the first trial, cobia (initial weight 49.3 g per fish) was randomly assigned to one of the six experimental diets and fed to apparent satiation twice daily. At the end of the first trial, weight gain in cobia was not significantly impacted by protein levels with values ranging from 333% (50% CP) to 353% (40% CP). However, lipid significantly (P b 0.05) affected weight gain with fish fed the diet containing 18% total lipid returning the lowest growth of 293%. Feed efficiency ratio values were not significantly impacted by dietary protein or lipid levels and ranged from 0.46 (50% CP/18% lipid) to 0.51 (50% CP/6 and 12% lipid). Survival was significantly impacted by protein and lipid with fish fed the diets containing 50% CP and 18% lipid having lower (P b 0.05) survival rates of 90%. In the second trial, smaller fish were utilized (7.4 g average initial weight) under identical experimental conditions and dietary formulations. Weight gain was not significantly affected by protein or lipid levels and ranged from 1099% in fish fed the diet containing 40% CP/18% lipid to 1305% in fish fed the diet containing 50% CP/12% lipid. Feed efficiency ratio values, visceral somatic and hepatosomatic indices were significantly affected by protein and/or lipid. Muscle and liver lipid were impacted by dietary lipid (P = 0.0203 and 0.0012, respectively). Muscle protein was significantly impacted by dietary protein levels, while liver protein was affected by both main effects. Dietary protein and lipid had no impact on muscle ash. These data suggest that juvenile cobia can thrive on a wide range of protein and lipid levels, as well as a range of protein to energy ratios. Positive impacts of optimizing the protein component in terms of economic and environmental concerns, coupled with the ability to maintain the rapid growth rates this species are renowned for at lower dietary lipid levels, point towards beneficial consequences of further refinement of commercial cobia production feeds.

Research paper thumbnail of Bioimpedance assessment of body composition in cobia Rachycentron canadum (L. 1766)

Aquaculture, 2007

Sixty juvenile cobia (Rachycentron canadum; 28.3 ± 0.13 g wet wt) were randomly distributed into ... more Sixty juvenile cobia (Rachycentron canadum; 28.3 ± 0.13 g wet wt) were randomly distributed into each of 12 tanks in a recirculation unit (n = 5 tank − 1). Fish were fed one of two diets (47:8 or 47:20 protein:lipid) at 6-8% body wt d − 1 for 6 weeks. Each week, the composition of fish (n = 5) from each dietary treatment was calculated by measuring the impedance (resistance and reactance) of a current (x μA AC and kHz) passed through a live animal. Electrodes were positioned at morphologically discrete points on the dorsal left hand side of the animal. After bioimpedance (BIA) assessment, the identical fish were sacrificed and their body composition determined using traditional, chemical methods. Results generated by chemical analyses were regressed against BIA data. Linear regression analysis was performed utilizing compositional analysis (protein, lipid and ash) as the observed values and BIA assessment for the predicted. Regressions for each body composition parameter produced high correlations in all relationships: resistance (in parallel) and protein (adj. R 2 = 0.9569), resistance (in parallel) and total body water (adj. R 2 = 0.9894), reactance (in parallel) and total body ash (adj. R 2 = 0.8547), reactance (in series) and dry matter (adj. R 2 = 0.9272) and reactance (in series) and fat-free mass (adj. R 2 = 0.9916). The F value tests (P b 0.0001) revealed significant correlations between the independent and dependent variables for each body composition parameter. Correlations for each regression indicate strong linear relationships between impedance and proximate analysis variables with values of 1:1. This indicates that this BIA methodology can be utilized as an inexpensive, non-lethal, on the farm determination of proximate composition.

Research paper thumbnail of Replacement of fish meal in cobia (Rachycentron canadum) diets using an organically certified protein

Aquaculture, 2006

A six-week feeding trial was conducted to evaluate the use of a yeast-based, certified organic pr... more A six-week feeding trial was conducted to evaluate the use of a yeast-based, certified organic protein source as a replacement for fish meal in diets for cobia. Five experimental diets were formulated to provide 40% crude protein and 11% dietary lipid (dry matter basis) with the yeast-based protein source replacing Special Select® menhaden fish meal at 25%, 50%, 75% and 100% of dietary protein. Ten juvenile cobia (initial weight 11.5 g/fish) were randomly stocked in triplicate 300 l circular fiberglass tanks (n = 30 treatment − 1) and hand-fed the diets based upon total tank biomass two times daily at 0900 and 1400 h. Fish were group weighed weekly to monitor performance and adjust feeding rations. Water temperature and salinity were maintained at 27°C and 15‰, respectively. At the end of the feeding trial, weight gain, ranging from 86% to 512%, and feed conversion ratio values, ranging from 1.9 to 5.8, were significantly affected by the inclusion of the yeast-based protein source, with decreasing values as inclusion levels of the yeast-based protein source rose above 25% of dietary protein. Cobia fed the diet containing 25% of dietary protein from the yeastbased protein source had equal weight gain and feed conversion ratio values as fish fed the control diet composed of 100% fish meal (503 vs. 512 and 1.9 vs. 1.9, respectively). Biological indices including hepatosomatic index, visceral somatic index and muscle ratio were all similarly affected by inclusion of the yeast-based protein source, with significant impacts when inclusion levels rose above 25% of dietary protein. As with the weight gain and feed efficiency ratio values, fish fed the diet containing 25% of protein from the yeast-based source had similar values as those observed in the control animals. This study represents the first attempt to utilize an organically certified protein source as a replacement for fish meal in diets for juvenile cobia. Although levels of inclusion of the yeast-based protein source above 50% of dietary protein resulted in detrimental effects on production characteristics, the data clearly suggest that, at a minimum, 25% of dietary protein can be provided by this yeast-based protein in diets for cobia.

Research paper thumbnail of Exoenzymes in Aquafeeds with Particular Reference to Microbal Phytase: A Review

Croatian Journal of Fisheries, Apr 5, 2002

Summary The global aquaculture industry has come under increasing pressure to optimize production... more Summary The global aquaculture industry has come under increasing pressure to optimize production efficiency while reducing environmental loadings. These new demands, which have been accompanied in certain countries by legislation, have stimulated the development of elite low output dietary formulations. Several feed manufacturers have developed diets with modified energy: protein ratios, which reduce environmental phosphorus loadings with minimum impact upon fish growth. However, problems relating ...

Research paper thumbnail of Paraziti, Bolesti I Deformacijske Promjene Kod Vrste Cobia

Ribarstvo, Mar 31, 2008

Sažetak Cobia, Rachycentron canadum, jedna je od predstavnica porodice Rachycentridae (Red Percif... more Sažetak Cobia, Rachycentron canadum, jedna je od predstavnica porodice Rachycentridae (Red Perciformes) i kao toplovodna riba nađena je u tropskim i suptropskim vodama. Ova je vrsta ustanovljena u istočnim vodama Sredozemlja. Cobia se na Tajvanu uzgaja od ranih 1990–ih, a danas se njezin uzgoj proširio na jugoistočnu i istočnu Aziju, Meksički zaljev i Karibe, kao i SAD. Mnogi narodi rade na prilagodbi kobije kao nove vrste za uzgoj, jer je vrlo zanimljiva zbog svojih odličnih karakteristika kao što su dobar rast s produkcijom od 6 kg ...

Research paper thumbnail of Vaccination of Hybrid Striped Bass: Growth, Immune Reaction and Gene Expression

Ribarstvo, Oct 3, 2012

Sažetak Hybrid striped bass (42.6+ 4.9 g wet wt; 139.3+ 6.1 mm length), were randomly stocked int... more Sažetak Hybrid striped bass (42.6+ 4.9 g wet wt; 139.3+ 6.1 mm length), were randomly stocked into one of 6 tanks (n= 6 tank-1) of a custom designed, recirculating life support system (RLSS). Water quality was as follows: DO2 (6.5 0.6 mg l-1), pH (7.7 0.5), TAN (0.06-1.31 mg l-1), nitrite (0.06-0.60 mg l-1) and nitrate (2.0-32.1 mg l-1), salinity 5 ppt, temperature 28±1 oC. A 12: 12 photophase: scotophase was used, with a 30 min. dusk-dawn dimming of lights. Fish were fed at 4% body wt d-1 as two separate feedings (08.00 ...

Research paper thumbnail of Sustainable feeds for cobia aquaculture: case studies with organically certifiable protein sources

… biotechnology in the …, 2006

This article discusses an alternative protein source (NuPro) not only for herbivorous and omnivor... more This article discusses an alternative protein source (NuPro) not only for herbivorous and omnivorous fish species but also for high level marine carnivores such as the cobia ( Rachycentron canadum), a truly novel and potentially lucrative product.

Research paper thumbnail of TOTAL REPLACEMENT OF FISHMEAL WITH AN ORGANICALLY CERTIFIED YEAST–BASED PROTEIN IN PACIFIC WHITE SHRIMP (Litopenaeus Vannamei) DIETS: LABORATORY AND FIELD TRIALS

Ribarstvo, Jun 30, 2006

Sažetak The feasibility of totally replacing the fishmeal component of marine shrimp (Litopenaeus... more Sažetak The feasibility of totally replacing the fishmeal component of marine shrimp (Litopenaeus vannamei) diets was examined both in the laboratory setting and during a full–scale commercial trial. Animals were fed either a traditional fishmeal–based diet or one in which complete replacement of fishmeal, on a per protein basis, was manufactured using a yeast–based product, NuPro®. Laboratory studies determined that irrespective of diet fed, no difference in shrimp performance (weight gain, survival and SGR) occurred. A field trial ...

Research paper thumbnail of Coconut oil and beef tallow, but not tricaprylin, can replace menhaden oil in the diet of red drum (Sciaenops ocellatus) without adversely affecting growth or fatty acid composition

The Journal of nutrition, 1995

The ability of juvenile red drum (Sciaenops ocellatus) to utilize medium-chain triglycerides (MCT... more The ability of juvenile red drum (Sciaenops ocellatus) to utilize medium-chain triglycerides (MCT) and other saturated dietary lipids was investigated in two 6-wk feeding experiments. Diets contained solvent-extracted menhaden fish meal to which menhaden fish oil (control), coconut oil, corn oil, beef tallow or various levels of MCT as tricaprylin (30, 46, 65 and 80% of total lipid) were added. Diets were fed to triplicate groups of juvenile red drum in aquaria containing brackish (6%) water. In the first feeding experiment, red drum fed the control diet had the greatest weight gains and feed efficiencies. Weight gain, but not feed was slightly, of fish fed corn oil and fish fed coconut oil was slightly (P < 0.05) lower. In the second feeding experiment, fish fed coconut oil and those fed beef tallow had significantly higher weight gains and feed efficiencies than did fish fed the control diet. Fish fed the diets containing tricaprylin at all inclusion levels in both feeding expe...

Research paper thumbnail of Effects of dietary lipids on body composition and liver function in juvenile red drum, Sciaenops ocellatus

This study was conducted to evaluate the effects of different concentrations of dietary lipids on... more This study was conducted to evaluate the effects of different concentrations of dietary lipids on body composition and liver function in juvenile red drum, Sciaenops ocellatus. Diets were formulated to contain 40% crude protein from solvent-extracted menhaden fish meal and 0, 7, 14 or 21% lipid from menhaden fish oil. The basal diet, without supplemental fish oil, contained lipid at 0.4% of dry weight. The diets were fed to groups of 25 juvenile red drum initially averaging 7.3 ± 0.18 g fish −1 in a recirculating culture system for 8 weeks and weight gain was recorded. After an additional 8 weeks, 16 fish from each treatment were sacrificed and the following measurements were recorded: hepatosomatic index (HSI), intraperitoneal fat (IPF) ratio, and liver α-tocopherol, malondialdehyde (MDA) formation, and cytochrome P-4501A activity (measured as 7-ethoxyresorufin O-deethylase (EROD) activity). The activity of alanine and aspartate aminotransferases and concentrations of α-tocopherol also were measured in plasma. Weight gain was significantly (p < 0.05) affected by dietary lipid concentration, with values ranging from 361% of initial weight for fish fed the basal diet to 527% of initial weight for fish fed the diet containing 7% lipid. The HSI and IPF ratio values also were significantly affected by lipid with the lowest values recorded for fish fed the basal diet and the highest values observed in fish fed the diet containing 21% lipid. Increasing dietary lipid significantly increased oxidative stress as reflected in reduced α-tocopherol in liver and plasma and increased MDA formation in the liver, although no overt pathological signs were observed. These findings suggest that lipid concentrations between 7 and 14%, when the diet contains 60 IU vitamin E kg −1 , are likely to limit oxidative stress and result in normal physiological responses of red drum.

Research paper thumbnail of Aquanomics: The application of genomic technologies to aquaculture

12.1 Introduction 12.2 The current state of genomic play 12.3 Homology analysis of zebrafish prob... more 12.1 Introduction 12.2 The current state of genomic play 12.3 Homology analysis of zebrafish probe sequences against cichlid genomic resources 12.4 Dietary manipulation of intestinal gene expression 12.5 Conclusion Keywords References

Research paper thumbnail of Use of Microbial Flocs Generated from Tilapia Effluent as a Nutritional Supplement for Shrimp, Litopenaeus vannamei, in Recirculating Aquaculture Systems

Journal of the World Aquaculture Society, 2008

Recovering nutrients in a fish effluent to be used as a supplemental feed for shrimp culture coul... more Recovering nutrients in a fish effluent to be used as a supplemental feed for shrimp culture could ease constraints (e.g., environmental issues and high production cost) that have limited the US shrimp farming industry in the past. In this study under laboratory scale conditions, fish effluent was collected from a commercial tilapia farm and nutrients from the waste stream were offered as supplemental feed as either (1) untreated solids from tilapia effluent or (2) microbial flocs generated from the biological treatment of the effluent by reducing soluble chemical oxygen demand .80%. The first feeding trial demonstrated that microbial flocs contributed significantly (P , 0.05) to overall growth while untreated solids did not. Moreover, microbial flocs were larger and contained higher levels (P , 0.05) of protein. The second feeding trial investigated different feeding rates of commercial diets with and without microbial floc supplementation. Weekly measurements of mass and specific growth rates demonstrated that microbial flocs significantly (P , 0.05) contributed to shrimp performance. Weekly food conversion ratios were also reported. Water quality in shrimp systems during both studies was within safe levels, and no differences (P. 0.05) between treatments were observed for dissolved oxygen, nitrate-nitrogen, nitrite-nitrogen, pH, salinity, total ammonia nitrogen, and temperature.

Research paper thumbnail of Chemical, Physical and Sensorial Differences in Farmed Southern Flounder ( Paralichthys lethostigma ) Fed Commercial or Crab Meal-Supplemented Diets

Journal of Aquatic Food Product Technology, 2006

ABSTRACT A 12-week feeding trial was conducted to determine the effects of a commercial and a cra... more ABSTRACT A 12-week feeding trial was conducted to determine the effects of a commercial and a crab meal-supplemented diet on sensory properties of southern flounder (Paralichthys lethostigma). Proximate analysis, color, fatty acid composition, texture and sensory analyses were performed on the fillets. A significant difference in flavor was found between fillets fed on a commercial or a crab-meal supplemented diet. No significant difference was found between the fish fillets when comparing fat, protein, fiber content and texture. However, ...

Research paper thumbnail of Efficacy of Concentrated Algal Paste During Greenwater Phase of Cobia Larviculture

Journal of Applied Aquaculture, 2008

The purpose of this study was to determine if concentrated algal paste could effectively replace ... more The purpose of this study was to determine if concentrated algal paste could effectively replace live algae during the greenwater stage of cobia fingerling production without negative impact upon larval growth or survival. Mean cobia survival per tank from 2 dph through post weaning at 28 dph for the live algae treatment was 24.44 ± 2.43% (mean ± SD) as

Research paper thumbnail of Performance of Advanced Juvenile Cobia,Rachycentron canadum, Reared Under Different Thermal Regimes: Evidence for Compensatory Growth and a Method for Cold Banking

Journal of Applied Aquaculture, 2007

ABSTRACT Two trials were undertaken to examine the growth response of juvenile cobia, Rachycentro... more ABSTRACT Two trials were undertaken to examine the growth response of juvenile cobia, Rachycentron canadum, at varying temperatures. The initial trial was conducted to determine the effect of various temperatures (18, 23, and 29° C) on weight gain and feed efficiency. The second trial investigated the effect of elevating water temperature in which fish maintained at 18° C and 23° C to a temperature close to their optimum (29° C). The latter study was undertaken in order to determine the effect of thermal shifts upon ...

Research paper thumbnail of Taurine supplementation to alternative dietary proteins used in fish meal replacement enhances growth of juvenile cobia (Rachycentron canadum)

Aquaculture, 2007

Two separate 8 week feeding trials were conducted to examine the impacts of fish meal replacement... more Two separate 8 week feeding trials were conducted to examine the impacts of fish meal replacement with an organically certifiable yeast-based protein source with and without supplementation of methionine, tryptophan, and taurine to diets for juvenile cobia. In the first trial, diets were formulated to contain 41% crude protein and 13% lipid, and a yeast-based protein replaced fish meal at 50 and 75% of dietary protein with and without supplemental taurine at 0.5 g/100 g dry diet. The control diet contained 100% herring fish meal. Methionine and tryptophan were added to all diets except the control to resemble the amino acid profile of fish meal. Results from this study indicated that fish fed diets supplemented with taurine exhibited significantly higher weight gain and better feed efficiencies than all other fish. Diet significantly impacted biological indices such as muscle ratio (MR), visceral somatic index (VSI), and hepatosomatic index (HSI). The 75% yeast-based protein diet without taurine returned the lowest MR values and the highest VSI and HSI values. In the second trial, diets were formulated to contain 43% crude protein and 11% lipid, with the control diet containing 100% herring fish meal and the same yeast-based protein replacing fish meal at 50, 75, and 100% of dietary protein. All diets except the control were supplemented with taurine at 0.5 g/100 g dry diet. Results from this study indicated that increasing amount of yeast-based protein led to decreased weight gains and feed efficiencies regardless of taurine supplementation. However, weight gain and feed efficiencies did increase when compared to a previous study [Lunger, A.N., McLean, E., Craig, S.R., 2007. The effects of organic protein supplementation upon growth, feed conversion and texture quality parameters in juvenile cobia (Rachycentron canadum). Aquaculture 264, 342-352] using identical diet formulations except for taurine supplementation. MR values tended to decrease while VSI and HSI values tended to increase with increasing fish meal replacement. It is obvious from the results from both of the present studies that taurine supplementation does have a significant impact on growth and feed efficiency of juvenile cobia when they are fed diets containing high levels of plant-based proteins as

Research paper thumbnail of The effects of organic protein supplementation upon growth, feed conversion and texture quality parameters of juvenile cobia (Rachycentron canadum)

Aquaculture, 2007

An eight week feeding trial was conducted to examine the impacts of organically certifiable alter... more An eight week feeding trial was conducted to examine the impacts of organically certifiable alternate protein sources on growth, feed efficiency, biological indices, fillet proximate composition and fillet quality in juvenile cobia. Diets were formulated to be isonitrogenous and isocaloric. The control diet provided 45% crude protein from Special Select® menhaden fish meal and 10% total lipid. The remaining diets were formulated with 25 and 40% inclusion of NuPro® (an organically certified yeast-derived protein source), and 40% inclusion of organically certified soybean meal, soybean isolate, or hemp seed meal. Two additional diets were formulated to contain a mixture of all organic protein sources at 23% with 8% fish meal or 25% and no fish meal. Diets were fed to triplicate groups of juvenile cobia (initial weight 10 g/fish) in 300 L circular tanks connected as part of a recirculating aquaculture system. Weight gain ranged from 167 to 1138% increase from initial weight and was similar for all fish fed diets containing 40% of any given alternate protein source. Fish fed the blended diet with 8% fish meal exhibited significantly lower weight gain, SGR, and FE ratio values than all other fish. Cobia fed the diet without any fish meal did not survive to the end of the study. Biological indices such as muscle ratio (MR), visceral somatic index (VSI), and packed cell volume (PCV) were all similar between fish fed the control diet and those fed diets with up to 40% alternate protein. Fish fed the diet with only 8% fish meal had significantly lower MR, PCV, and plasma protein, and significantly higher VSI. All fish exhibited similar fillet proximate composition for protein, lipid, dry matter, and ash except for those fed the diet containing 8% fish meal. Alternate protein source did appear to impact the fillet texture of cobia. Generally speaking, plant protein sources returned higher textural characteristics than the fish meal control. At all time points and all texture parameters, cobia fed the diet containing hemp seed meal returned the highest values except for distance to rupture in the final time point. Results indicate that up to 40% fish meal protein can be replaced by any of the organically certifiable alternate proteins that were used in this study without detrimental impacts to weight gain, feed efficiency, biological indices, or fillet composition in juvenile cobia. Our results also suggest that alternate proteins have differential effects upon final product quality, which may have implications in terms of cobia processing and development of industrial products.

Research paper thumbnail of Dietary mannan oligosaccharide enhances salinity tolerance and gut development of larval cobia

Aquaculture, 2008

The potential beneficial effects of supplementing live feeds with mannan oligosaccharide (MOS; Bi... more The potential beneficial effects of supplementing live feeds with mannan oligosaccharide (MOS; BioMos®) upon cobia Rachycentron canadum larval performance were examined. Characteristics of fish examined included survival to weaning, growth, ability to withstand osmotic stress and the degree of development of the brush border of the intestine. Live feeds included rotifers (Brachionus plicatilis) and Artemia which were enriched for 24 h with a commercial enrichment media alone or in combination with 0.2% (dry weight basis) MOS. Salinity challenges were performed at 6 days post-hatch (dph) and at 7, 13, and 14 dph (0 and 65 g L − 1 for 6 dph; 0 and 55 − 1 7+ dph) corresponding to transitions in feeding, to examine the ability of larval cobia to survive stress. Differences (P b 0.05) in survival, favoring cobia receiving MOS-supplemented feeds were discerned at 6 and 7 days post-hatch (dph) when fish were challenged at 0 g L − 1 and at 13 dph when challenged with 55 g L − 1 salinity water. Electron microscopy of the mid-intestine of developing larvae revealed that MOS-supplemented diets enhanced (P b 0.05) the height of microvilli while reducing (P b 0.05) the occurrence and size of supranuclear vacuoles. Supplementation of diets with MOS could assist cobia larvae in maintaining allostasis especially when reared at sub-optimal salinities.

Research paper thumbnail of Use of soy protein concentrate and novel ingredients in the total elimination of fish meal and fish oil in diets for juvenile cobia, Rachycentron canadum

Aquaculture, 2010

Achieving true sustainability in fish farming requires the replacement of most of the fish meal a... more Achieving true sustainability in fish farming requires the replacement of most of the fish meal and fish oil utilized as feedstuffs. The present experiment reports 2 feeding trials that resulted in the total replacement of fish meal and fish oil in juvenile cobia (Rachycentron canadum). The first trial was conceived as a 2 × 3 factorial design with three levels of fish meal replacement (FMR; 50, 75 and 100% of dietary protein) by soy protein concentrate (SPC), and two levels of mannan oligosaccharide (MOS) supplementation (0 or 0.3% of the diet). Since MOS has been reported to promote gut health and integrity, it was included in order to verify whether it would ease high levels of FMR. Lipids were supplied by menhaden oil. In the second feeding trial, fish meal was replaced by various combinations of SPC and soybean meal, again with or without MOS supplementation. In addition, some diets were supplemented with purified amino acids. Lipids were supplied by fish oil. A final diet (NOFM) was formulated using SPC, a marine worm meal, a nucleotide-rich yeast extract protein source, and MOS. In this last diet, lipids were supplied with a mix of soy oil and a DHArich algal meal, thereby completely eliminating both fish meal and fish oil. Over both feeding trials, juvenile cobia consistently exhibited excellent performance at 75% FMR and less. MOS did not have a significant effect, although a beneficial trend was observed in the first trial at 100% FMR. In the second trial, the fish fed the NOFM diet exhibited one of the best weight gains and feed efficiencies, with no mortality and no impact on muscle and liver composition. This result illustrates the crucial importance of the selection of feedstuffs for FMR and fish oil, since the NOFM diet did not receive amino acid supplementation. While this represents the first successful elimination of fish meal and fish oil in aquafeeds for cobia, the consistent, successful replacement of 94% of the fish meal in the other diets is actually more promising to the future as they solely utilized commodities traded (soy products) as replacement sources, which is the only road to true environmental and economical sustainability for the aquaculture industry.

Research paper thumbnail of Do fish enhance tank mixing?

Aquaculture, 2005

The design of fish rearing tanks represents a critical stage in the development of optimal aquacu... more The design of fish rearing tanks represents a critical stage in the development of optimal aquaculture systems, especially in the context of recirculating systems. Poor hydrodynamics can compromise water quality, waste management and the physiology and behaviour of fish, and thence, production potential and operational profitability. The hydrodynamic performance of tanks, therefore, represents an important parameter during the tank design process. Because there are significant complexities in combining the rigid principles of hydrodynamics with the stochastic behaviour of fish, however, most data upon tank hydrokinetics has been derived using tanks void of fish. Clearly, the presence of randomly moving objects, such as fish, in a water column will influence not only tank volumes by displacing water, but due to their activity, water dynamics and associated in-tank processes. In order to determine the impact of fish presence upon tank hydrodynamics, Rhodamine fluorometry was employed to examine mixing within a recirculating aquaculture system. Two different methods were compared, traditional, outlet-based measurements and a technique that employed in-tank data acquisition. Circular tanks were employed during data collection either in the presence or absence of experimental fish-red drum Sciaenops ocellatus (n =36; 5 kg total wet wt); and at two flow rates. Irrespective of flow rate, the presence of fish dramatically enhanced the mixing process (P b 0.001), with mixing times in tanks with fish being one-third that for tanks without animals. In-tank dispersion coefficients and dispersion numbers also differed (P b 0.001) in the presence of fish, irrespective of flow. Presence or absence of fish had no effect upon hydraulic residence or circulation times. Unlike measurements at the outlet, in-tank observations were more able to isolate the effects of stochastic, fish-induced mixing, from deterministic, hydrodynamic mixing.

Research paper thumbnail of Juvenile cobia (Rachycentron canadum) can utilize a wide range of protein and lipid levels without impacts on production characteristics

Aquaculture, 2006

Two, 6 week feeding trials were conducted to evaluate the impacts of protein and lipid on weight ... more Two, 6 week feeding trials were conducted to evaluate the impacts of protein and lipid on weight gain, feed efficiency ratio values and biological indices of juvenile cobia (Rachycentron canadum). Utilizing a 2 × 3 factorial design, experimental diets containing two levels of crude protein (CP; 40 and 50%) and three levels of lipid (6, 12 and 18%), providing 14.4, 15.1 and 16.6 kJ available energy/g dry diet (calculated), respectively, were formulated for use in both feeding trials. In the first trial, cobia (initial weight 49.3 g per fish) was randomly assigned to one of the six experimental diets and fed to apparent satiation twice daily. At the end of the first trial, weight gain in cobia was not significantly impacted by protein levels with values ranging from 333% (50% CP) to 353% (40% CP). However, lipid significantly (P b 0.05) affected weight gain with fish fed the diet containing 18% total lipid returning the lowest growth of 293%. Feed efficiency ratio values were not significantly impacted by dietary protein or lipid levels and ranged from 0.46 (50% CP/18% lipid) to 0.51 (50% CP/6 and 12% lipid). Survival was significantly impacted by protein and lipid with fish fed the diets containing 50% CP and 18% lipid having lower (P b 0.05) survival rates of 90%. In the second trial, smaller fish were utilized (7.4 g average initial weight) under identical experimental conditions and dietary formulations. Weight gain was not significantly affected by protein or lipid levels and ranged from 1099% in fish fed the diet containing 40% CP/18% lipid to 1305% in fish fed the diet containing 50% CP/12% lipid. Feed efficiency ratio values, visceral somatic and hepatosomatic indices were significantly affected by protein and/or lipid. Muscle and liver lipid were impacted by dietary lipid (P = 0.0203 and 0.0012, respectively). Muscle protein was significantly impacted by dietary protein levels, while liver protein was affected by both main effects. Dietary protein and lipid had no impact on muscle ash. These data suggest that juvenile cobia can thrive on a wide range of protein and lipid levels, as well as a range of protein to energy ratios. Positive impacts of optimizing the protein component in terms of economic and environmental concerns, coupled with the ability to maintain the rapid growth rates this species are renowned for at lower dietary lipid levels, point towards beneficial consequences of further refinement of commercial cobia production feeds.

Research paper thumbnail of Bioimpedance assessment of body composition in cobia Rachycentron canadum (L. 1766)

Aquaculture, 2007

Sixty juvenile cobia (Rachycentron canadum; 28.3 ± 0.13 g wet wt) were randomly distributed into ... more Sixty juvenile cobia (Rachycentron canadum; 28.3 ± 0.13 g wet wt) were randomly distributed into each of 12 tanks in a recirculation unit (n = 5 tank − 1). Fish were fed one of two diets (47:8 or 47:20 protein:lipid) at 6-8% body wt d − 1 for 6 weeks. Each week, the composition of fish (n = 5) from each dietary treatment was calculated by measuring the impedance (resistance and reactance) of a current (x μA AC and kHz) passed through a live animal. Electrodes were positioned at morphologically discrete points on the dorsal left hand side of the animal. After bioimpedance (BIA) assessment, the identical fish were sacrificed and their body composition determined using traditional, chemical methods. Results generated by chemical analyses were regressed against BIA data. Linear regression analysis was performed utilizing compositional analysis (protein, lipid and ash) as the observed values and BIA assessment for the predicted. Regressions for each body composition parameter produced high correlations in all relationships: resistance (in parallel) and protein (adj. R 2 = 0.9569), resistance (in parallel) and total body water (adj. R 2 = 0.9894), reactance (in parallel) and total body ash (adj. R 2 = 0.8547), reactance (in series) and dry matter (adj. R 2 = 0.9272) and reactance (in series) and fat-free mass (adj. R 2 = 0.9916). The F value tests (P b 0.0001) revealed significant correlations between the independent and dependent variables for each body composition parameter. Correlations for each regression indicate strong linear relationships between impedance and proximate analysis variables with values of 1:1. This indicates that this BIA methodology can be utilized as an inexpensive, non-lethal, on the farm determination of proximate composition.

Research paper thumbnail of Replacement of fish meal in cobia (Rachycentron canadum) diets using an organically certified protein

Aquaculture, 2006

A six-week feeding trial was conducted to evaluate the use of a yeast-based, certified organic pr... more A six-week feeding trial was conducted to evaluate the use of a yeast-based, certified organic protein source as a replacement for fish meal in diets for cobia. Five experimental diets were formulated to provide 40% crude protein and 11% dietary lipid (dry matter basis) with the yeast-based protein source replacing Special Select® menhaden fish meal at 25%, 50%, 75% and 100% of dietary protein. Ten juvenile cobia (initial weight 11.5 g/fish) were randomly stocked in triplicate 300 l circular fiberglass tanks (n = 30 treatment − 1) and hand-fed the diets based upon total tank biomass two times daily at 0900 and 1400 h. Fish were group weighed weekly to monitor performance and adjust feeding rations. Water temperature and salinity were maintained at 27°C and 15‰, respectively. At the end of the feeding trial, weight gain, ranging from 86% to 512%, and feed conversion ratio values, ranging from 1.9 to 5.8, were significantly affected by the inclusion of the yeast-based protein source, with decreasing values as inclusion levels of the yeast-based protein source rose above 25% of dietary protein. Cobia fed the diet containing 25% of dietary protein from the yeastbased protein source had equal weight gain and feed conversion ratio values as fish fed the control diet composed of 100% fish meal (503 vs. 512 and 1.9 vs. 1.9, respectively). Biological indices including hepatosomatic index, visceral somatic index and muscle ratio were all similarly affected by inclusion of the yeast-based protein source, with significant impacts when inclusion levels rose above 25% of dietary protein. As with the weight gain and feed efficiency ratio values, fish fed the diet containing 25% of protein from the yeast-based source had similar values as those observed in the control animals. This study represents the first attempt to utilize an organically certified protein source as a replacement for fish meal in diets for juvenile cobia. Although levels of inclusion of the yeast-based protein source above 50% of dietary protein resulted in detrimental effects on production characteristics, the data clearly suggest that, at a minimum, 25% of dietary protein can be provided by this yeast-based protein in diets for cobia.

Research paper thumbnail of Exoenzymes in Aquafeeds with Particular Reference to Microbal Phytase: A Review

Croatian Journal of Fisheries, Apr 5, 2002

Summary The global aquaculture industry has come under increasing pressure to optimize production... more Summary The global aquaculture industry has come under increasing pressure to optimize production efficiency while reducing environmental loadings. These new demands, which have been accompanied in certain countries by legislation, have stimulated the development of elite low output dietary formulations. Several feed manufacturers have developed diets with modified energy: protein ratios, which reduce environmental phosphorus loadings with minimum impact upon fish growth. However, problems relating ...

Research paper thumbnail of Paraziti, Bolesti I Deformacijske Promjene Kod Vrste Cobia

Ribarstvo, Mar 31, 2008

Sažetak Cobia, Rachycentron canadum, jedna je od predstavnica porodice Rachycentridae (Red Percif... more Sažetak Cobia, Rachycentron canadum, jedna je od predstavnica porodice Rachycentridae (Red Perciformes) i kao toplovodna riba nađena je u tropskim i suptropskim vodama. Ova je vrsta ustanovljena u istočnim vodama Sredozemlja. Cobia se na Tajvanu uzgaja od ranih 1990–ih, a danas se njezin uzgoj proširio na jugoistočnu i istočnu Aziju, Meksički zaljev i Karibe, kao i SAD. Mnogi narodi rade na prilagodbi kobije kao nove vrste za uzgoj, jer je vrlo zanimljiva zbog svojih odličnih karakteristika kao što su dobar rast s produkcijom od 6 kg ...

Research paper thumbnail of Vaccination of Hybrid Striped Bass: Growth, Immune Reaction and Gene Expression

Ribarstvo, Oct 3, 2012

Sažetak Hybrid striped bass (42.6+ 4.9 g wet wt; 139.3+ 6.1 mm length), were randomly stocked int... more Sažetak Hybrid striped bass (42.6+ 4.9 g wet wt; 139.3+ 6.1 mm length), were randomly stocked into one of 6 tanks (n= 6 tank-1) of a custom designed, recirculating life support system (RLSS). Water quality was as follows: DO2 (6.5 0.6 mg l-1), pH (7.7 0.5), TAN (0.06-1.31 mg l-1), nitrite (0.06-0.60 mg l-1) and nitrate (2.0-32.1 mg l-1), salinity 5 ppt, temperature 28±1 oC. A 12: 12 photophase: scotophase was used, with a 30 min. dusk-dawn dimming of lights. Fish were fed at 4% body wt d-1 as two separate feedings (08.00 ...

Research paper thumbnail of Sustainable feeds for cobia aquaculture: case studies with organically certifiable protein sources

… biotechnology in the …, 2006

This article discusses an alternative protein source (NuPro) not only for herbivorous and omnivor... more This article discusses an alternative protein source (NuPro) not only for herbivorous and omnivorous fish species but also for high level marine carnivores such as the cobia ( Rachycentron canadum), a truly novel and potentially lucrative product.

Research paper thumbnail of TOTAL REPLACEMENT OF FISHMEAL WITH AN ORGANICALLY CERTIFIED YEAST–BASED PROTEIN IN PACIFIC WHITE SHRIMP (Litopenaeus Vannamei) DIETS: LABORATORY AND FIELD TRIALS

Ribarstvo, Jun 30, 2006

Sažetak The feasibility of totally replacing the fishmeal component of marine shrimp (Litopenaeus... more Sažetak The feasibility of totally replacing the fishmeal component of marine shrimp (Litopenaeus vannamei) diets was examined both in the laboratory setting and during a full–scale commercial trial. Animals were fed either a traditional fishmeal–based diet or one in which complete replacement of fishmeal, on a per protein basis, was manufactured using a yeast–based product, NuPro®. Laboratory studies determined that irrespective of diet fed, no difference in shrimp performance (weight gain, survival and SGR) occurred. A field trial ...

Research paper thumbnail of Coconut oil and beef tallow, but not tricaprylin, can replace menhaden oil in the diet of red drum (Sciaenops ocellatus) without adversely affecting growth or fatty acid composition

The Journal of nutrition, 1995

The ability of juvenile red drum (Sciaenops ocellatus) to utilize medium-chain triglycerides (MCT... more The ability of juvenile red drum (Sciaenops ocellatus) to utilize medium-chain triglycerides (MCT) and other saturated dietary lipids was investigated in two 6-wk feeding experiments. Diets contained solvent-extracted menhaden fish meal to which menhaden fish oil (control), coconut oil, corn oil, beef tallow or various levels of MCT as tricaprylin (30, 46, 65 and 80% of total lipid) were added. Diets were fed to triplicate groups of juvenile red drum in aquaria containing brackish (6%) water. In the first feeding experiment, red drum fed the control diet had the greatest weight gains and feed efficiencies. Weight gain, but not feed was slightly, of fish fed corn oil and fish fed coconut oil was slightly (P < 0.05) lower. In the second feeding experiment, fish fed coconut oil and those fed beef tallow had significantly higher weight gains and feed efficiencies than did fish fed the control diet. Fish fed the diets containing tricaprylin at all inclusion levels in both feeding expe...

Research paper thumbnail of Effects of dietary lipids on body composition and liver function in juvenile red drum, Sciaenops ocellatus

This study was conducted to evaluate the effects of different concentrations of dietary lipids on... more This study was conducted to evaluate the effects of different concentrations of dietary lipids on body composition and liver function in juvenile red drum, Sciaenops ocellatus. Diets were formulated to contain 40% crude protein from solvent-extracted menhaden fish meal and 0, 7, 14 or 21% lipid from menhaden fish oil. The basal diet, without supplemental fish oil, contained lipid at 0.4% of dry weight. The diets were fed to groups of 25 juvenile red drum initially averaging 7.3 ± 0.18 g fish −1 in a recirculating culture system for 8 weeks and weight gain was recorded. After an additional 8 weeks, 16 fish from each treatment were sacrificed and the following measurements were recorded: hepatosomatic index (HSI), intraperitoneal fat (IPF) ratio, and liver α-tocopherol, malondialdehyde (MDA) formation, and cytochrome P-4501A activity (measured as 7-ethoxyresorufin O-deethylase (EROD) activity). The activity of alanine and aspartate aminotransferases and concentrations of α-tocopherol also were measured in plasma. Weight gain was significantly (p < 0.05) affected by dietary lipid concentration, with values ranging from 361% of initial weight for fish fed the basal diet to 527% of initial weight for fish fed the diet containing 7% lipid. The HSI and IPF ratio values also were significantly affected by lipid with the lowest values recorded for fish fed the basal diet and the highest values observed in fish fed the diet containing 21% lipid. Increasing dietary lipid significantly increased oxidative stress as reflected in reduced α-tocopherol in liver and plasma and increased MDA formation in the liver, although no overt pathological signs were observed. These findings suggest that lipid concentrations between 7 and 14%, when the diet contains 60 IU vitamin E kg −1 , are likely to limit oxidative stress and result in normal physiological responses of red drum.