Dominique Bureau - Profile on Academia.edu (original) (raw)
Papers by Dominique Bureau
Influence of ration level and rearing temperature on hepatic GHR1 and 2, and hepatic and intestinal TR? and TR? gene expression in late stages of rainbow trout embryos
J Fish Biol, 2007
ABSTRACT The study examined whether the early life-history temperature experience of rainbow trou... more ABSTRACT The study examined whether the early life-history temperature experience of rainbow trout Oncorhynchus mykiss embryos affects subsequent growth and expression of growth-related genes in the growing-up juveniles in response to variations in ration levels. Embryos were reared in a Heath incubator at either 8·5° C (E8·5) or 6·0° C (E6·0) until hatching, at which time they were transferred to grow-up tanks supplied with water at 8·5° C. At swim-up, the late stage embryos were subsequently fed a salmonid starter diet at levels of 5, 2 or 0·5% of live body mass per day. The body mass and proximate composition of the juveniles was examined when yolk absorbance was complete (21 days after the fish commenced feeding). Quantitative RT-PCR was used to examine the expression of mRNA encoding for growth hormone receptors 1 and 2 (GHR1 and GHR2) in the liver, and the two isoforms of thyroid hormone receptor (TRα and TRβ) in the liver and intestinal tract. Final body mass and total length, liver and intestinal masses, and total lipid content of the E8·5 treatment group were directly related to increased ration size. These variables in the E6·0 treatment group fed the 5% ration were significantly lower than for the comparable E8·5 treatment group, suggesting an effect of embryo rearing temperature on the subsequent growth of these late stage embryos as they undergo the transition from embryo to early juvenile. Intestinal TRα and TRβ mRNA abundance was directly related to ration size in the E8·5 treatment group, but not in the E6·0 treatment group. Conversely, hepatic TRα and TRβ mRNA abundance was significantly affected by ration size only in the E6·0 group, with TRβ and TRα abundance showing direct and inverse relationships with ration size, respectively. Hepatic GHR1 mRNA abundance was significantly and directly related to ration size in both the E8·5 and E6·0 treatment groups, but there were no differences in the abundance of hepatic GHR2 mRNA among any treatments.
![Research paper thumbnail of The partitioning of energy from digestible carbohydrates by rainbow trout, Oncorhynchus mykiss [microform]](https://attachments.academia-assets.com/41482582/thumbnails/1.jpg)
](A series of studies was carried out to examine the partitioning of the energy from dietary carboh... more A series of studies was carried out to examine the partitioning of the energy from dietary carbohydrates by rainbow trout. A pair-feeding technique, used for all the experiments, consisted of feeding the same amount of a basal diet, low in digestible carbohydrate, to the fish with different quantities of supplemental (digestible) carbohydrate. One group of fish was fed the basal diet, alone, while two other groups received supplemental glucose or gelatinized starch.
L'utilisation de résidus agricoles pour la production piscicole dans le région du nord-est de la Thaïlande [microforme] /
ABSTRACT
A study was conducted to investigate how the allocation of energy to growth and maintenance diffe... more A study was conducted to investigate how the allocation of energy to growth and maintenance differs between rainbow trout and Atlantic salmon and how the diet affects energy allocation. Rainbow trout and Atlantic salmon were handfed to satiation four isoenergetic diets (DE = 20 MJ/kg) with different digestible protein/digestible energy ratios (DP/DE), i.e., 24, 22, 20, and 18 g/MJ, achieved through reduction of DP level (53 to 39%) and increase of lipid level (19 to 26%). Intake of metabolizable energy (ME), protein (PD), and lipid (LD) gain were determined. Data were analyzed by multivariate analysis of PD and LD on ME. Maintenance energy requirements (MEm) and efficiency of ME utilization for PD (kp) and LD (k f ) were estimated. The fraction of ME intake above maintenance for PD (X) was defined as linear function of body weight with slope (d) and intercept (c) estimated simultaneously with the above parameters. The MEm did not differ (P > 0.05) be-tween rainbow trout and Atlantic salmon (20 kJ/day/kg 0.8 ). On the other hand, Kp, c, and d were significantly different (P < 0.05) between the two species, independently of the diet. The ME intake above MEm channeled towards PD (c) was higher in salmon than trout (57 vs. 55%; P < 0.05). The change in partitioning of ME toward PD due to the change in body weight was negative for trout (d = -0.18) while it was positive for salmon (d = 0.16). The values of d agreed well with the increase of LD/PD with body weight for trout and the decrease of LD/PD with body weight for salmon which may have been related to the maturation status of this fish and the associated loss of lipid observed with maturing salmon. The Kp was significantly higher for salmon compared to trout (0.52 ± 0.06 vs. 0.43 ± 0.06; P < 0.05) and independent of the diet while K f was 0.81 ± 0.13 irrespective of species or diet. Lower cost of protein deposition for salmon compared to trout suggests differences in protein metabolism between these two species. Studies on protein turnover rates and metabolic utilization of nutrients for PD are required to gain insight on kp differences between salmon and trout.
Nitrogen (N) and phosphorus (P) metabolic wastes produced by fish are at the origin of most disso... more Nitrogen (N) and phosphorus (P) metabolic wastes produced by fish are at the origin of most dissolved N and P waste produced by intensive aquaculture operations. Dissolved N and P wastes impose constraints on productivity of the operations and may lead to environmental degradation problems. Reducing outputs of these dissolved wastes is considered a key element for the long-term sustainability of aquaculture in many parts of the world.
Aquaculture Research
Different synthetic forms of supplemental methionine (Met) are produced commercially by various m... more Different synthetic forms of supplemental methionine (Met) are produced commercially by various manufacturers. Limited information exists on the bioavailability of these different forms in commercially relevant fish species. The objective of this study was to compare the relative bioavailability of L-methionine and a methionine hydroxy analogue calcium salt (MHA-Ca) to DL-methionine in a commercially relevant species, rainbow trout, using a linear slope-ratio assay. In addition, the ability of the rainbow trout to effectively convert the D-isomer of methionine into the biologically active L-isomer was studied by comparing the relative bioavailability of L-methionine to DL-methionine. Nine (9) diets were created from a methionine-deficient basal diet which was supplemented with graded equimolar levels of methionine (0.1%, 0.2%, 0.3% of diet by weight) from either DL-methionine, L-methionine and methionine hydroxy analogue calcium salt (MHA-Ca). Diets were fed in triplicate (IBW = 24.0 AE 0.6 g) for 12 weeks using a pair-feeding protocol. The basal diet was formulated to be deficient in both methionine (0.5%) and cysteine (0.3%), whereas meeting all other known nutritional requirements of rainbow trout. MHA-Ca was found to be less available (P < 0.05) than DL-methionine with relative bioavailability values of 69%, 60% and 73% based upon weight gain, growth rate (TGC) and retained nitrogen values respectively. No significant differences (P > 0.05) in bioavailability were found between DL-methionine and L-methionine.
Efficiency of Conversion of Feed Inputs into Animal Biomass
Feeding and Digestive Functions in Fishes, 2008
Assessing the bioavailability of l-lysine sulfate compared to l-lysine HCl in rainbow trout (Oncorhynchus mykiss)
A growth trial was conducted to determine relative bioavailability between two commercially avail... more A growth trial was conducted to determine relative bioavailability between two commercially available sources of supplemental lysine in rainbow trout. A basal diet, which was formulated to be deficient in lysine while meeting all other known nutritional requirements for rainbow trout was supplemented with increasing levels (0.1, 0.2, 0.4 & 0.6%) of l-lysine on an equimolar basis from one of two supplemental lysine sources; l-lysine sulfate (Bio-lys) or l-lysine HCl. Diets were fed in triplicate to groups of rainbow trout (IBW = 25 ± 0.6 g) for 12 weeks using a pair-feeding protocol. Fish which received diets containing supplemental lysine from either source exhibited improved weight gain (p < 0.05), growth rate (p < 0.05), retained nitrogen (p < 0.05), retained nitrogen efficiency (p < 0.05) and feed efficiency (p < 0.01) compared to fish which received the unsupplemented basal diet. Similarly increasing levels of lysine supplementation from either source resulted in ...
The feed industry is relying more on economical feedstuffs while formulating feeds to lower the e... more The feed industry is relying more on economical feedstuffs while formulating feeds to lower the existing nutritional specifications. These new strategies are leading feed manufacturers to explore and utilize novel approaches for better nutrient availability in feeds. Exogenous protease enzymes have been shown to improve protein digestibility and feed efficiency using in-vivo studies in both poultry and swine. There is a need for practical in-vitro techniques as current techniques such as enzyme kinetic assays are problematic and in-vivo trials are costly and labourious. The main objectives of this study was to develop and compare two in-vitro techniques, the HCl-Pepsin protein digestibility and the total soluble amino acid methods, that are able to differentiate between control diets and diets containing a protease enzyme (Jefo Nutrition Inc., Canada). > Two in-vitro techniques were developed to evaluate nutritive value of commercially pelleted shrimp diets (containing 0, 175 and...
7. Li M, Bureau D, King WA, Leatherland J F. 2010. The Actions of In Ovo Cortisol on Egg Fertility, Embryo Development and the Expression of Growth-Related Genes in Rainbow Trout Embryos, and the Growth Performance of Juveniles. Molecular Reproduction and Development.77: 922-931
Molecular Reproduction and Development
Journal of Applied Ichthyology, 2014
Extended phosphorus (P) deficiency has been linked to an increase of skeletal deformities in farm... more Extended phosphorus (P) deficiency has been linked to an increase of skeletal deformities in farmed salmonids. To date, X-ray examination still is the most practical way to detect abnormalities that are not externally visible. The aim of this study was to develop a standardized method based on empirical measurements that provides an early radiograph-based detection of deformities. Triploid all-female rainbow trout (60.8 AE 1.6 g) were fed with phosphorus (P)-deficient and P-sufficient diets (total P = 0.5% and 0.92%, respectively). Experiments were carried out in 12 circular re-circulating tanks (n = 140/tank; 8.5-52.7 kg m À3 ; 12 AE 0.3°C; 18L: 6D). All fish were x-rayed at week 5, 15 and 24 to monitor vertebral abnormalities. Fish were assigned to a vertebral phenotype (normal, biconcave or compressed) when all vertebrae of the caudal region (V31-44) showed the same type of abnormalities. At week 9, 18 and 27, ten fish per tank were randomly sampled according to their vertebral phenotype. Vertebrae V38-V39 were collected and a second X-ray was performed to confirm the above-mentioned phenotypes. Morphometrics (vertebral length and height; intervertebral distances and vertebral body angles) were measured directly on radiographs. For all parameters measured, comparisons were made between normal P-sufficient fish and different scenarios of vertebral development (normal, restored, stable and aggravated) in P-deficient fish. The two parameters showing the most sensitivity were the median intervertebral distance and dorsal/ventral vertebral endplate angles. When analysed together, these two parameters allow a quantitative distinction of the different vertebral phenotypes. Measuring dorsal/ventral vertebral endplate angles seems a promising approach to detect aberrant vertebral development at early stages as slight changes were observed in P-deficient vertebrae that were assessed as normal by visual examination. Further studies including histological examinations and comparison with other radiological imaging techniques are required to confirm these results.
Toxins, 2015
An 8-week feeding trial was conducted to examine effects of wheat naturally contaminated with Fus... more An 8-week feeding trial was conducted to examine effects of wheat naturally contaminated with Fusarium mycotoxins (deoxynivalenol, DON 41 mg·kg −1 ) on growth performance and selected health indices of red tilapia (Oreochromis niloticus × O. mossambicus; initial weight = 4.3 g/fish). Five experimental diets were formulated by replacement of clean wheat with naturally contaminated wheat resulting in graded levels of DON and zearalenone (ZEN) (Diet 1 0.07/0.01, Diet 2 0.31/0.09, Diet 3 0.50/0.21, Diet 4 0.92/0.37 and Diet 5 1.15/0.98 mg·kg −1 ). Groups of 50 fish were randomly allocated into each of 20 aquaria and fed to near-satiety for eight weeks. Growth rate, feed intake and feed efficiency of fish fed the experimental diets decreased linearly with increasing levels of
Aquaculture Economics & Management, 2007
& Applications of a rapid appraisal approach to identify locally available feed ingredients in fe... more & Applications of a rapid appraisal approach to identify locally available feed ingredients in feed formulation, production, and socio-economics of Nile tilapia aquaculture in Bangladesh are discussed. Three diets of 35%, 30%, and 25% crude protein were formulated using locally available ingredients, and their essential amino acid profiles were assessed for Nile tilapia. Six production scenarios were constructed using these diets and two culture periods of 100 and 150 days were considered. The production scenarios with 35% protein yielded the highest productivity and profitability over the 150-day culture period followed by the 30% protein scenario. Identification of locally available ingredients and their application in small-scale Nile tilapia aquaculture may lead to: (1) increased availability of inexpensive sources of fish production for poor people; (2) increased fish consumption; (3) increased self employment and involvement of women in productive activities; and (4) increased household income to reduce poverty.
Predicting body composition of tilapia
Fisheries Science
Accurate prediction of proximate composition for a commercially cultured fish at a particular bod... more Accurate prediction of proximate composition for a commercially cultured fish at a particular body weight could help to reduce overall feed waste, improve feed efficiency, and increase profitability. We studied the relationship between biochemical composition of Nile tilapia and its wet weight for the range of minimum and maximum body weight found in the published literature. We also tested the predictive value of regression equations. Logarithmic trends of the proximate composition showed a linear trend for tilapia up to 0.4 g. The trend formed a plateau for tilapia larger than 5 g. The slopes (b) for water, protein, fat, and ash contents as percent body-weight were -0.008, 0.003, 0.003, and 0.002 respectively. The slopes were close to “0” and did not change significantly after removing data from fishes smaller than 5 g in all four cases. Mean percent error of water (-0.145) and protein (-0.769) showed no differences between them. A large percent error mean for fat (-39.179) sugges...
Journal of fish diseases, Jan 27, 2014
Diets containing deoxynivalenol (DON) were fed to rainbow trout Oncorhynchus mykiss (Walbaum) for... more Diets containing deoxynivalenol (DON) were fed to rainbow trout Oncorhynchus mykiss (Walbaum) for 4 weeks followed by experimental infection (intraperitoneal) with Flavobacterium psychrophilum (4.1 × 10(6) colony-forming units [CFU] mL(-1) ). Mortality of rainbow trout fed either 6.4 mg kg(-1) DON or trout pair-fed the control diet was significantly reduced (P < 0.05) in comparison with trout fed the control diet to apparent satiation (<0.1 mg kg(-1) DON). In a second experiment, trout were fed one of three experimental diets; a control diet, a diet produced with corn naturally contaminated with DON (3.3 mg kg(-1) DON) or a diet containing purified DON (3.8 mg kg(-1) ); however, these fish were not experimentally infected. The presence of DON resulted in significant reduction (P < 0.0001) in feed intake as well as weight gain after 4 weeks. Respiratory burst of head-kidney leucocytes isolated from rainbow trout fed diets containing purified DON (3.8 mg kg(-1) ) was signific...
Comparing efficiency of metabolizable energy utilization by rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar) using factorial and multivariate approaches
Journal of animal science, 2005
A study was conducted to compare utilization of ME for growth vs. maintenance in rainbow trout an... more A study was conducted to compare utilization of ME for growth vs. maintenance in rainbow trout and Atlantic salmon. Fish were hand-fed to satiation one of four isoenergetic diets (DE = 20 MJ/kg, as-fed basis) with different digestible protein (DP) to DE ratios (24, 22, 20, and 18 g/MJ). Intake of ME (kJ/d), energy deposited as protein (PD, kJ/d), and energy deposited as lipid (LD, kJ/d) were determined by a comparative slaughter technique. Data were analyzed by a factorial approach or by multivariate analysis of PD and LD on ME. Maintenance energy requirements (ME(m)) and efficiency of ME utilization for PD (k(p)) and LD (k(f)) were estimated with both approaches. For the multivariate analysis, an additional parameter, the fraction of ME intake above maintenance used for PD (X) was defined as linear function of BW, with slope (d) and intercept (c) estimated simultaneously with the above parameters. Estimates were highly dependent on the approach and assumptions used. The ME(m) and k...
Dynamic simulation of phosphorus utilization in salmonid fish
Nutrient digestion and utilization in farm animals: modelling approaches, 2006
Abstract Minimizing phosphorus (P) wastes is a key factor for environmental sustainability of fre... more Abstract Minimizing phosphorus (P) wastes is a key factor for environmental sustainability of freshwater aquaculture operations. A dynamic model was constructed to simulate P utilization in salmonid fish through digestion, body deposition and excretion into urine and ...
Influence of ration level and rearing temperature on hepatic GHR1 and 2, and hepatic and intestinal TR? and TR? gene expression in late stages of rainbow trout embryos
J Fish Biol, 2007
ABSTRACT The study examined whether the early life-history temperature experience of rainbow trou... more ABSTRACT The study examined whether the early life-history temperature experience of rainbow trout Oncorhynchus mykiss embryos affects subsequent growth and expression of growth-related genes in the growing-up juveniles in response to variations in ration levels. Embryos were reared in a Heath incubator at either 8·5° C (E8·5) or 6·0° C (E6·0) until hatching, at which time they were transferred to grow-up tanks supplied with water at 8·5° C. At swim-up, the late stage embryos were subsequently fed a salmonid starter diet at levels of 5, 2 or 0·5% of live body mass per day. The body mass and proximate composition of the juveniles was examined when yolk absorbance was complete (21 days after the fish commenced feeding). Quantitative RT-PCR was used to examine the expression of mRNA encoding for growth hormone receptors 1 and 2 (GHR1 and GHR2) in the liver, and the two isoforms of thyroid hormone receptor (TRα and TRβ) in the liver and intestinal tract. Final body mass and total length, liver and intestinal masses, and total lipid content of the E8·5 treatment group were directly related to increased ration size. These variables in the E6·0 treatment group fed the 5% ration were significantly lower than for the comparable E8·5 treatment group, suggesting an effect of embryo rearing temperature on the subsequent growth of these late stage embryos as they undergo the transition from embryo to early juvenile. Intestinal TRα and TRβ mRNA abundance was directly related to ration size in the E8·5 treatment group, but not in the E6·0 treatment group. Conversely, hepatic TRα and TRβ mRNA abundance was significantly affected by ration size only in the E6·0 group, with TRβ and TRα abundance showing direct and inverse relationships with ration size, respectively. Hepatic GHR1 mRNA abundance was significantly and directly related to ration size in both the E8·5 and E6·0 treatment groups, but there were no differences in the abundance of hepatic GHR2 mRNA among any treatments.
A series of studies was carried out to examine the partitioning of the energy from dietary carboh... more A series of studies was carried out to examine the partitioning of the energy from dietary carbohydrates by rainbow trout. A pair-feeding technique, used for all the experiments, consisted of feeding the same amount of a basal diet, low in digestible carbohydrate, to the fish with different quantities of supplemental (digestible) carbohydrate. One group of fish was fed the basal diet, alone, while two other groups received supplemental glucose or gelatinized starch.
L'utilisation de résidus agricoles pour la production piscicole dans le région du nord-est de la Thaïlande [microforme] /
ABSTRACT
A study was conducted to investigate how the allocation of energy to growth and maintenance diffe... more A study was conducted to investigate how the allocation of energy to growth and maintenance differs between rainbow trout and Atlantic salmon and how the diet affects energy allocation. Rainbow trout and Atlantic salmon were handfed to satiation four isoenergetic diets (DE = 20 MJ/kg) with different digestible protein/digestible energy ratios (DP/DE), i.e., 24, 22, 20, and 18 g/MJ, achieved through reduction of DP level (53 to 39%) and increase of lipid level (19 to 26%). Intake of metabolizable energy (ME), protein (PD), and lipid (LD) gain were determined. Data were analyzed by multivariate analysis of PD and LD on ME. Maintenance energy requirements (MEm) and efficiency of ME utilization for PD (kp) and LD (k f ) were estimated. The fraction of ME intake above maintenance for PD (X) was defined as linear function of body weight with slope (d) and intercept (c) estimated simultaneously with the above parameters. The MEm did not differ (P > 0.05) be-tween rainbow trout and Atlantic salmon (20 kJ/day/kg 0.8 ). On the other hand, Kp, c, and d were significantly different (P < 0.05) between the two species, independently of the diet. The ME intake above MEm channeled towards PD (c) was higher in salmon than trout (57 vs. 55%; P < 0.05). The change in partitioning of ME toward PD due to the change in body weight was negative for trout (d = -0.18) while it was positive for salmon (d = 0.16). The values of d agreed well with the increase of LD/PD with body weight for trout and the decrease of LD/PD with body weight for salmon which may have been related to the maturation status of this fish and the associated loss of lipid observed with maturing salmon. The Kp was significantly higher for salmon compared to trout (0.52 ± 0.06 vs. 0.43 ± 0.06; P < 0.05) and independent of the diet while K f was 0.81 ± 0.13 irrespective of species or diet. Lower cost of protein deposition for salmon compared to trout suggests differences in protein metabolism between these two species. Studies on protein turnover rates and metabolic utilization of nutrients for PD are required to gain insight on kp differences between salmon and trout.
Nitrogen (N) and phosphorus (P) metabolic wastes produced by fish are at the origin of most disso... more Nitrogen (N) and phosphorus (P) metabolic wastes produced by fish are at the origin of most dissolved N and P waste produced by intensive aquaculture operations. Dissolved N and P wastes impose constraints on productivity of the operations and may lead to environmental degradation problems. Reducing outputs of these dissolved wastes is considered a key element for the long-term sustainability of aquaculture in many parts of the world.
Aquaculture Research
Different synthetic forms of supplemental methionine (Met) are produced commercially by various m... more Different synthetic forms of supplemental methionine (Met) are produced commercially by various manufacturers. Limited information exists on the bioavailability of these different forms in commercially relevant fish species. The objective of this study was to compare the relative bioavailability of L-methionine and a methionine hydroxy analogue calcium salt (MHA-Ca) to DL-methionine in a commercially relevant species, rainbow trout, using a linear slope-ratio assay. In addition, the ability of the rainbow trout to effectively convert the D-isomer of methionine into the biologically active L-isomer was studied by comparing the relative bioavailability of L-methionine to DL-methionine. Nine (9) diets were created from a methionine-deficient basal diet which was supplemented with graded equimolar levels of methionine (0.1%, 0.2%, 0.3% of diet by weight) from either DL-methionine, L-methionine and methionine hydroxy analogue calcium salt (MHA-Ca). Diets were fed in triplicate (IBW = 24.0 AE 0.6 g) for 12 weeks using a pair-feeding protocol. The basal diet was formulated to be deficient in both methionine (0.5%) and cysteine (0.3%), whereas meeting all other known nutritional requirements of rainbow trout. MHA-Ca was found to be less available (P < 0.05) than DL-methionine with relative bioavailability values of 69%, 60% and 73% based upon weight gain, growth rate (TGC) and retained nitrogen values respectively. No significant differences (P > 0.05) in bioavailability were found between DL-methionine and L-methionine.
Efficiency of Conversion of Feed Inputs into Animal Biomass
Feeding and Digestive Functions in Fishes, 2008
Assessing the bioavailability of l-lysine sulfate compared to l-lysine HCl in rainbow trout (Oncorhynchus mykiss)
A growth trial was conducted to determine relative bioavailability between two commercially avail... more A growth trial was conducted to determine relative bioavailability between two commercially available sources of supplemental lysine in rainbow trout. A basal diet, which was formulated to be deficient in lysine while meeting all other known nutritional requirements for rainbow trout was supplemented with increasing levels (0.1, 0.2, 0.4 & 0.6%) of l-lysine on an equimolar basis from one of two supplemental lysine sources; l-lysine sulfate (Bio-lys) or l-lysine HCl. Diets were fed in triplicate to groups of rainbow trout (IBW = 25 ± 0.6 g) for 12 weeks using a pair-feeding protocol. Fish which received diets containing supplemental lysine from either source exhibited improved weight gain (p < 0.05), growth rate (p < 0.05), retained nitrogen (p < 0.05), retained nitrogen efficiency (p < 0.05) and feed efficiency (p < 0.01) compared to fish which received the unsupplemented basal diet. Similarly increasing levels of lysine supplementation from either source resulted in ...
The feed industry is relying more on economical feedstuffs while formulating feeds to lower the e... more The feed industry is relying more on economical feedstuffs while formulating feeds to lower the existing nutritional specifications. These new strategies are leading feed manufacturers to explore and utilize novel approaches for better nutrient availability in feeds. Exogenous protease enzymes have been shown to improve protein digestibility and feed efficiency using in-vivo studies in both poultry and swine. There is a need for practical in-vitro techniques as current techniques such as enzyme kinetic assays are problematic and in-vivo trials are costly and labourious. The main objectives of this study was to develop and compare two in-vitro techniques, the HCl-Pepsin protein digestibility and the total soluble amino acid methods, that are able to differentiate between control diets and diets containing a protease enzyme (Jefo Nutrition Inc., Canada). > Two in-vitro techniques were developed to evaluate nutritive value of commercially pelleted shrimp diets (containing 0, 175 and...
7. Li M, Bureau D, King WA, Leatherland J F. 2010. The Actions of In Ovo Cortisol on Egg Fertility, Embryo Development and the Expression of Growth-Related Genes in Rainbow Trout Embryos, and the Growth Performance of Juveniles. Molecular Reproduction and Development.77: 922-931
Molecular Reproduction and Development
Journal of Applied Ichthyology, 2014
Extended phosphorus (P) deficiency has been linked to an increase of skeletal deformities in farm... more Extended phosphorus (P) deficiency has been linked to an increase of skeletal deformities in farmed salmonids. To date, X-ray examination still is the most practical way to detect abnormalities that are not externally visible. The aim of this study was to develop a standardized method based on empirical measurements that provides an early radiograph-based detection of deformities. Triploid all-female rainbow trout (60.8 AE 1.6 g) were fed with phosphorus (P)-deficient and P-sufficient diets (total P = 0.5% and 0.92%, respectively). Experiments were carried out in 12 circular re-circulating tanks (n = 140/tank; 8.5-52.7 kg m À3 ; 12 AE 0.3°C; 18L: 6D). All fish were x-rayed at week 5, 15 and 24 to monitor vertebral abnormalities. Fish were assigned to a vertebral phenotype (normal, biconcave or compressed) when all vertebrae of the caudal region (V31-44) showed the same type of abnormalities. At week 9, 18 and 27, ten fish per tank were randomly sampled according to their vertebral phenotype. Vertebrae V38-V39 were collected and a second X-ray was performed to confirm the above-mentioned phenotypes. Morphometrics (vertebral length and height; intervertebral distances and vertebral body angles) were measured directly on radiographs. For all parameters measured, comparisons were made between normal P-sufficient fish and different scenarios of vertebral development (normal, restored, stable and aggravated) in P-deficient fish. The two parameters showing the most sensitivity were the median intervertebral distance and dorsal/ventral vertebral endplate angles. When analysed together, these two parameters allow a quantitative distinction of the different vertebral phenotypes. Measuring dorsal/ventral vertebral endplate angles seems a promising approach to detect aberrant vertebral development at early stages as slight changes were observed in P-deficient vertebrae that were assessed as normal by visual examination. Further studies including histological examinations and comparison with other radiological imaging techniques are required to confirm these results.
Toxins, 2015
An 8-week feeding trial was conducted to examine effects of wheat naturally contaminated with Fus... more An 8-week feeding trial was conducted to examine effects of wheat naturally contaminated with Fusarium mycotoxins (deoxynivalenol, DON 41 mg·kg −1 ) on growth performance and selected health indices of red tilapia (Oreochromis niloticus × O. mossambicus; initial weight = 4.3 g/fish). Five experimental diets were formulated by replacement of clean wheat with naturally contaminated wheat resulting in graded levels of DON and zearalenone (ZEN) (Diet 1 0.07/0.01, Diet 2 0.31/0.09, Diet 3 0.50/0.21, Diet 4 0.92/0.37 and Diet 5 1.15/0.98 mg·kg −1 ). Groups of 50 fish were randomly allocated into each of 20 aquaria and fed to near-satiety for eight weeks. Growth rate, feed intake and feed efficiency of fish fed the experimental diets decreased linearly with increasing levels of
Aquaculture Economics & Management, 2007
& Applications of a rapid appraisal approach to identify locally available feed ingredients in fe... more & Applications of a rapid appraisal approach to identify locally available feed ingredients in feed formulation, production, and socio-economics of Nile tilapia aquaculture in Bangladesh are discussed. Three diets of 35%, 30%, and 25% crude protein were formulated using locally available ingredients, and their essential amino acid profiles were assessed for Nile tilapia. Six production scenarios were constructed using these diets and two culture periods of 100 and 150 days were considered. The production scenarios with 35% protein yielded the highest productivity and profitability over the 150-day culture period followed by the 30% protein scenario. Identification of locally available ingredients and their application in small-scale Nile tilapia aquaculture may lead to: (1) increased availability of inexpensive sources of fish production for poor people; (2) increased fish consumption; (3) increased self employment and involvement of women in productive activities; and (4) increased household income to reduce poverty.
Predicting body composition of tilapia
Fisheries Science
Accurate prediction of proximate composition for a commercially cultured fish at a particular bod... more Accurate prediction of proximate composition for a commercially cultured fish at a particular body weight could help to reduce overall feed waste, improve feed efficiency, and increase profitability. We studied the relationship between biochemical composition of Nile tilapia and its wet weight for the range of minimum and maximum body weight found in the published literature. We also tested the predictive value of regression equations. Logarithmic trends of the proximate composition showed a linear trend for tilapia up to 0.4 g. The trend formed a plateau for tilapia larger than 5 g. The slopes (b) for water, protein, fat, and ash contents as percent body-weight were -0.008, 0.003, 0.003, and 0.002 respectively. The slopes were close to “0” and did not change significantly after removing data from fishes smaller than 5 g in all four cases. Mean percent error of water (-0.145) and protein (-0.769) showed no differences between them. A large percent error mean for fat (-39.179) sugges...
Journal of fish diseases, Jan 27, 2014
Diets containing deoxynivalenol (DON) were fed to rainbow trout Oncorhynchus mykiss (Walbaum) for... more Diets containing deoxynivalenol (DON) were fed to rainbow trout Oncorhynchus mykiss (Walbaum) for 4 weeks followed by experimental infection (intraperitoneal) with Flavobacterium psychrophilum (4.1 × 10(6) colony-forming units [CFU] mL(-1) ). Mortality of rainbow trout fed either 6.4 mg kg(-1) DON or trout pair-fed the control diet was significantly reduced (P < 0.05) in comparison with trout fed the control diet to apparent satiation (<0.1 mg kg(-1) DON). In a second experiment, trout were fed one of three experimental diets; a control diet, a diet produced with corn naturally contaminated with DON (3.3 mg kg(-1) DON) or a diet containing purified DON (3.8 mg kg(-1) ); however, these fish were not experimentally infected. The presence of DON resulted in significant reduction (P < 0.0001) in feed intake as well as weight gain after 4 weeks. Respiratory burst of head-kidney leucocytes isolated from rainbow trout fed diets containing purified DON (3.8 mg kg(-1) ) was signific...
Comparing efficiency of metabolizable energy utilization by rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar) using factorial and multivariate approaches
Journal of animal science, 2005
A study was conducted to compare utilization of ME for growth vs. maintenance in rainbow trout an... more A study was conducted to compare utilization of ME for growth vs. maintenance in rainbow trout and Atlantic salmon. Fish were hand-fed to satiation one of four isoenergetic diets (DE = 20 MJ/kg, as-fed basis) with different digestible protein (DP) to DE ratios (24, 22, 20, and 18 g/MJ). Intake of ME (kJ/d), energy deposited as protein (PD, kJ/d), and energy deposited as lipid (LD, kJ/d) were determined by a comparative slaughter technique. Data were analyzed by a factorial approach or by multivariate analysis of PD and LD on ME. Maintenance energy requirements (ME(m)) and efficiency of ME utilization for PD (k(p)) and LD (k(f)) were estimated with both approaches. For the multivariate analysis, an additional parameter, the fraction of ME intake above maintenance used for PD (X) was defined as linear function of BW, with slope (d) and intercept (c) estimated simultaneously with the above parameters. Estimates were highly dependent on the approach and assumptions used. The ME(m) and k...
Dynamic simulation of phosphorus utilization in salmonid fish
Nutrient digestion and utilization in farm animals: modelling approaches, 2006
Abstract Minimizing phosphorus (P) wastes is a key factor for environmental sustainability of fre... more Abstract Minimizing phosphorus (P) wastes is a key factor for environmental sustainability of freshwater aquaculture operations. A dynamic model was constructed to simulate P utilization in salmonid fish through digestion, body deposition and excretion into urine and ...