Lawrence Nwanna - Academia.edu (original) (raw)

Papers by Lawrence Nwanna

Aquaculture Research, 2010

The e¡ect of diets supplemented with varied levels of inorganic phosphorus (P) (NaH 2 PO 4) on th... more The e¡ect of diets supplemented with varied levels of inorganic phosphorus (P) (NaH 2 PO 4) on the growth, body composition, nutrient digestibility and mineralization in common carp (Cyprinus carpio L) was evaluated to determine the optimum P requirements. The six diets used were DPO, as the basal diet with a total P content of1.30 g kg À 1 , and DP1, DP2, DP3, DP4 and DP5, which contained 4.10, 6.70, 11.6, 14.9 and 23.4 g P kg À 1 respectively. Weight gain, SGR, apparent digestibility coe⁄cient of organic matter and P, whole body ash, P, Ca and Mg increased signi¢cantly with increasing dietary P levels while dry matter (DM), fat and Zn content decreased. Feed conversion ratio was the poorest (Po0.05) in ¢sh fed DPO, suggesting P de¢ciency. The apparent digestibility coe⁄cient of P was 18% in the DPO-fed group, which increased from 69% in DP1 to 92% in DP5 after P supplementation, revealing lower digestibility of the native P than that in NaH 2 PO 4. Broken-line analyses based on weight gain, P content of ¢sh bones and whole body against total dietary and digestible P (data in brackets) contents showed the optimum P requirement for the growth of common carp to be 6.87 (5.55) g kg À 1 DM, and the requirement for optimum mineralization in bones and whole body to be 9.10 (7.62) and 14.7 (13.2) g kg À 1 .

Journal of Animal Physiology and Animal Nutrition, 2008

Effect of phytase pre-treatment of dietary plant feed stuffs (PF) on growth and mineral concentra... more Effect of phytase pre-treatment of dietary plant feed stuffs (PF) on growth and mineral concentration in common carp (C. carpio L.) was investigated. Diets used were: C0, diet with no supplement; CI, diet with incubated PF; CP0, diet supplemented with 3 g P/kg; CPI, diet with incubated PF supplemented with 3 g P/kg; Phyt0, diet fortified with 4000 U phytase/kg; PhytI, diet with PF incubated with 4000 U phytase/ kg. Mean weight gain, SGR and FCR were the same (p < 0.05) in fish fed CP0, CPI or PhytI but less (p < 0.05) in other fish. Bone P was similar in fish fed CP0 (74.9), CPI (75.9) or PhytI (71.5 mg/g DM) but higher (p < 0.05) than in fish fed C0. Bone Ca and Mg were similar in fish fed CP0, CPI or PhytI but less (p < 0.05) in other fish. Bone Zn in fish fed C0, Phyt0 or PhytI was higher (p < 0.05) than that in fish fed CP0 or CPI. In conclusion, CP0, CPI and PhytI had the same effect, suggesting phytase pre-treatment as the most effective method. CPI did not have any advantage over CP0. Phytase increased mineral availability and utilization, which would minimize cost of mineral supplementation and discharges into the environment.

Suisan Zoshoku, 2006

Journal of Applied Aquaculture, 1999

Page 1. Dietary Arginine Requirement of the African Catfish, Clarias gariepinus Oyedapo A. Fagben... more Page 1. Dietary Arginine Requirement of the African Catfish, Clarias gariepinus Oyedapo A. Fagbenro Lawrence C. Nwanna Olabode T. Adebayo ABSTRACT. The dietary arginine requirement of the African catfish, Clarias gariepinus ...

Phytate can chelate amino acids in plant feedstuffs and lysine is the first limiting amino acid i... more Phytate can chelate amino acids in plant feedstuffs and lysine is the first limiting amino acid in wheat meals that can replace fish meal in low cost and environmentally friendly fish feed production. The study evaluated the effects of different levels of lysine (Lys-HCl) and a dose of phytase (0.2 g kg-1 diet) in wheat meal based diets on the production of all male Nile tilapia. Six treatments (T1-T6) were used including, diet 1 the control with no supplement, and diets 2-6 supplemented with (0.2 g kg-1) phytase; 2.96 g Lys kg-1; 2.96 g Lys kg-1 + (0.2 g kg-1) phytase; 5.82 g Lys kg-1; and 5.82 g Lys kg-1 + (0.2 g kg-1) phytase, respectively. The diets were fed to the fish for 56 days. Fish grew well from the initial weight of 6.75g to weight gain of 25.1c, 27.4c, 32.3bc, 35.2ab, 37.4ab and 40.5a g in treatments 1-6, respectively, increasing the weight gain by between 73 and 84%. The trend showed increasing performance with increasing levels of dietary Lys. Treatments 4, 5 and 6 pr...

Aqua-feeds with minimal phosphorus (P) and nitrogen (N) stressors on the environment are paramoun... more Aqua-feeds with minimal phosphorus (P) and nitrogen (N) stressors on the environment are paramount for eco-friendly aquaculture, as P and N are the major sources of aquatic pollution. This study investigated the effects of defatted soybean meal (DSM) plus phytase and dephytinized soy protein (DHP) plus phytase on the growth, N and P retention, N and P excretion and total P loadings by rainbow trout, Oncorhynchus mykiss. Seven isoproteic diets were formulated to contain, DSM (diet 1), DSM plus 5 g P kg -1 diet (diet 2), DSM plus 1500 U/kg phytase (diet 3), DSM plus 3000 U/kg phytase (diet 4), DHP (diet 5), DHP with 1500 U/kg phytase (diet 6) and DHP plus 3000 U/kg phytase (diet 7), making up treatments (T1-T7). Chromic oxide (1%) was added to the diets as inert marker for digestibility studies. The diets were tested on rainbow trout (25.6 ± 0.24 g) for 12 weeks. Results indicated no significant differences in the mean weight gain (MWG), specific growth rate (SGR) and food conversion ...

Fish farmers often use practical diets deficient in proteins in order to minimize costs and maxim... more Fish farmers often use practical diets deficient in proteins in order to minimize costs and maximize profits. A study conducted to determine the effects of DL-Met supplementation in such diets on the growth and carcass quality of African catfish Clarias gariepinus, showed that feeding fish with protein deficient diets retarded growth performance, reduced nutrients composition and increased the carcass lipid. However, supplementation of Met in the diets generally improved the fish growth performance, nutrient composition and enhanced the synthesis of other amino acids in the fish body. Similarly, supplementation of Met to protein deficient 35% crude protein (CP) diet raised the Met content of that diet that it produced fish with similar growth performance as those fed the control diets of 40 or 45% CP. The study also revealed no additional significant benefits by increasing the dietary protein level of the fish from 40 to 45%, thus confirming 40% protein as the requirement for the fi...

Effects of graded levels of phytase (Ronozyme P) in African catfish, Clarias gariepinus, diets we... more Effects of graded levels of phytase (Ronozyme P) in African catfish, Clarias gariepinus, diets were investigated with a view to determining the optimal level. Six isoproteic diets of 40% protein were formulated to contain 60% soybean meal and 20% fish meal. The soybean meal was oven toasted at 100•Ž for 15 min, dehulled and blended into powder before mixing with other ingredients. About 0.1% of Cr2O3 was added into the mixture as an inert maker for digestibility studies. Phytase was added at 0, 2000, 4000, 6000, 8000 and 10000 U kg-1 diet (corresponding to treatments 1-6) before pelleting. Fish (25.1•}1.22g) were randomly assigned to glass tanks with about 100 l of water at 12 fish per tank, and fed ad-libitum four times daily for 70 days. Results showed that fish administered diets of phytase had superior (P<0.05) mean weight gain (MWG) (%), and food conversion ratio (FCR) to fish fed diet without phytase. Specific growth rate (SGR) and apparent digestibility coefficient for pro...

Aquaculture, 2018

Abstract The increasing demand for pikeperch (Sander lucioperca) from recirculating aquaculture s... more Abstract The increasing demand for pikeperch (Sander lucioperca) from recirculating aquaculture systems (RAS) has raised the need for detailed knowledge on water quality parameters. Nitrate thresholds are of interest as nitrate accumulates in RAS and influences fish physiology. The trial was conducted in a recirculating aquaculture respirometer with pikeperch (average body weight (BW) 367 ± 1.1 g) successively reared at three different nitrate-nitrogen (NO3–N) concentrations (N30: 30 mg L−1, N120: 120 mg L−1 and N240: 240 mg L−1) and compared to a control group reared at the lowest possible nitrate-nitrogen concentration (N0: 5 mg L−1). Pikeperch were fed once per day with a commercial diet at three different feeding levels corresponding to 0.3% BW, 0.6% BW and 0.9% BW in triplicates for 8 days at either nitrate-nitrogen concentration before fasting for additional 3 days. Oxygen consumption and ammonia excretion were measured for 22-h in fed and fasting pikeperch to examine the influence of nitrate on energy metabolism. Metabolisable energy, retained energy and digestible energy requirements for maintenance (DEm) as well as the efficiency for energy utilisation (kg) and relative protein utilisation for energy metabolism (as ammonia quotient (AQ)) were determined. Specific dynamic action (SDA) was calculated to estimate the amount of energy spend on ingestion, digestion, absorption and assimilation of feed at different nitrate levels. SDA was significantly increased in the N240 treatment. Results of DEm showed a significant difference between N30 and N120 with DEm of N120 being about 73% higher than DEm of N30. The efficiency kg was significantly decreased between N240 and both N120 and N30 by 10% and 11% respectively. Increased values in AQ in the feed depleted fish in the N240 treatment indicates that fasting pikeperch in the high nitrate treatment had to use body protein to fuel an average of 46 ± 7% of their energy metabolism. The results of this trial show that pikeperch tolerate NO3–N concentrations of up to 240 mg L−1 but energy requirements are most favourable at concentrations of 30 mg L−1 NO3–N.

Animal Research International, 2008

Phosphorus (P) is a critical nutrient vital for growth and buffer systems in the blood. However, ... more Phosphorus (P) is a critical nutrient vital for growth and buffer systems in the blood. However, excess supply can lead to toxic effects in fish and eutrophication and pollution problems in the culture environment. African catfish (Clarias gariepinus) juveniles were fed diets containing different levels of inorganic phosphorus supplements to determine its optimum requirements for fish growth. Eleven diets were used. Their P content varied from 3.9 g/kg diet (for the basal diet) to 13.5 g/kg diet. Weight gain, specific growth rate, feed conversion ratio, carcass protein, and fat improved significantly from fish fed without supplemental P to fish fed 8 g P/kg and then declined consistently in fish fed with a diet supplemented with larger amounts of P. The P and Ca contents of the fish whole body increased significantly and showed linear relationship with increasing dietary P levels, whereas the Mg and Zn contents of the fish indicated a decreasing trend. Broken-line analysis based on ...

Pakistan Journal of Nutrition, 2003

Fish nutrition researchers often feed fishes at between 3-5% of their body weight daily. Environm... more Fish nutrition researchers often feed fishes at between 3-5% of their body weight daily. Environmental risks associated with excess feed leachate are so enormous in tropical waters leading to algal bloom which can toxify the aquaculture products and threaten their safety. Considering that feed requirements by fishes depend on a number of factors such as size, health status and the general condition of the culture environment; there is every need for the determination of the actual feed desired to meet their physiological needs, promote growth and reproduction based on peculiar conditions. This study was conducted to determine the appropriate feeding rate for tilapia, Oreochromis niloticus and consequential changes in the water quality. A 30% crude protein diet was fed to triplicate groups of O. niloticus fingerlings (10.13±0.58g) in glass tanks (75x45x40 cm) (20 fish/tank) at 2, 3, 4 and 5% body weight daily. The holding tanks were cleaned every two days after measuring the water quality parameters, pH, temperature and the dissolved oxygen. Results of the experiment indicated that the weight gain (WG, %) and specific growth rate (SGR) of the fishes fed at 3, 4 and 5% body weights were similar (p>0.05) but differed significantly (p<0.05) from the WG and SGR of the group of fishes fed at 2% body weight. However, there were no significant differences in FCR and PER of fishes fed at the various body weights. While the pH and the temperature of the culture media were not affected by the treatments, the dissolved oxygen was marginally lower in tanks fed at 4 and 5% body weights than in those fed at 2 and 3% body weights. The study established the optimum feeding rate for O. niloticus at 3% body weight daily, and the tendency for water quality deterioration with higher feeding rates.

Journal of Applied Aquaculture, 2002

Abstract The performance of poultry layer waste (PLW) meal as a dietry protein inclusion for hybr... more Abstract The performance of poultry layer waste (PLW) meal as a dietry protein inclusion for hybrid clariid catfish (Clarias gariepinus♂ ×Heterobranchus bidorsalis♀) fingerlings (hetero-clarias), cultivated in glass tanks, was evaluated. Four isonitrogenous diets (35% crude protein) were fed to unsexed hetero-clarias fingerlings for 90 days. The inclusion levels of the PLW meal were at 0%, 10%, 20% and 30%. Growth performance and nutrient utilization of the fish were based on percentage daily weight gains, specific growth rate, feed conversion ratio and protein efficiency ratio. There were no significant differences (P> 0.05) in growth performance and nutrient utilization of the fishes fed on diets containing up to 30% PLW inclusion. All fish fed diets containing PLW did better (P> 0.05) than those fed the control diet. The most cost-effective diet in terms of cost-weight gain was diet containing 10% PLW. These results indicate that up to 30% of PLW meal could be included in the diet of hybrid diet catfish.

Journal of Applied Aquaculture, 1999

ABSTRACT A 70-day growth study was conducted to quantify the dietary tryptophan requirement of th... more ABSTRACT A 70-day growth study was conducted to quantify the dietary tryptophan requirement of the African catfish, Clarias gariepinus using diets containing casein and gelatin as sources of intact protein, supplemented with crystalline amino acids, formulated to a crude protein content of 400 g/kg and gross energy content of 12 kJ/g dry matter. The diets, with graded levels of tryptophan (3-13 g/kg protein), were fed to triplicate groups of African catfish (11.5 1.1 g) twice a day up to satiation. Dietary tryptophan requirement estimated using break point analysis was 11 g/kg dietary protein, higher than the requirements recorded in literature for other fishes. Catfish fed diets containing tryptophan below 11 g/kg protein (tryptophan-deficient diets) showed reduced growth response and feed utilization (P < 0.05). Anorexia was observed after 10 days in catfish fed diets containing 3 or 5 g tryptophan/kg protein), and slight curvature of the catfish vertebral column was noted in catfish fed tryptophan defi...

Journal of Applied Aquaculture, 1999

Aquaculture Research, 2007

The e¡ect of dietary phytase on phosphorus (P) digestibility, growth, bone mineralization and pla... more The e¡ect of dietary phytase on phosphorus (P) digestibility, growth, bone mineralization and plasma P of common carp (Cyprinus carpio) was investigated. Five diets, D0, DP, PHYT1, PHYT2 and PHYT4, were used. D0 contained no supplement. DP was supplemented with 2.6 g P (Na 2 HPO 4 Â 2H 2 O) kg À1. PHYT1, PHYT2 and PHYT4 comprised 1000, 2000 and 4000 U phytase [Ronozyme P (CT)] kg À1. D0, PHYT1, PHYT2, PHYT4 had average of 7.95 g P kg À1 ; DP contained 10.3 g P kg À1. After 126 days of feeding, ¢sh grew from 115 to 347 g (D0), 583.7 g (DP), 352.6 g (PHYT1), 393.3 g (PHYT2) and 406.4 g (PHYT4). Addition of phytase signi¢cantly increased daily feed intake, but only led to a marginal improvement in the weight gain, SGR and FCR of ¢sh fed PHYT2 and PHYT4 compared with ¢sh fed D0. Fish fed DP showed the best (Po0.05) growth performances. Fish fed DP and PHYT4 signi¢cantly digested dietary P more than the ¢sh fed D0. Fish fed D0, PHYT1, PHYT2 and PHYT4 retained higher (Po0.05) Zn in their bones than ¢sh fed DP. However, there was no further e¡ect on bone mineralization. Plasma P scarcely improved by between 14% and 26% in ¢sh fed PHYT2 and PHYT4 relative to ¢sh fed D0. P concentration of the faeces was reduced by about 9^22% in ¢sh fed PHYT1 and PHYT4 compared with ¢sh fed D0.

Aquaculture Research, 2010

Journal of Animal Physiology and Animal Nutrition, 2008

Suisan Zoshoku, 2006

Journal of Applied Aquaculture, 1999

Aquaculture, 2018

Animal Research International, 2008

Pakistan Journal of Nutrition, 2003

Journal of Applied Aquaculture, 2002

Journal of Applied Aquaculture, 1999

Aquaculture Research, 2007