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1. Two studies were conducted to investigate the effect of feeding different concentration and forms of zinc (Zn) on the performance and tibia Zn status of broiler chicks. 2. In Experiment 1, chicks fed on the control or the diet supplemented with 12?mg of Zn as sulphate had lower feed intake, weight gain and tibia Zn content than other treatment groups. Chicks given 12 and 24 mg of organic Zn in starter and grower phases, respectively, had the same performance and tibia Zn content as those fed 40 mg of Zn as sulphate and the same performance but higher tibia Zn content than those given 12 mg of Zn as organic over the 42 d. 3. In Experiment 2, chicks given 24 mg organic Zn had greater weight gain than chicks fed on the other treatment diets in the starter period. Chicks fed on the control diet had lower tibia Zn content than chicks fed other treatment diets. Chicks given 80 mg Zn as sulphate had higher tibia Zn content than chicks fed the other treatment diets except those given 40 mg of Zn as sulphate. 4. The results from these trials indicate that feeding lower concentration of Zn as organic form may better promote the growth performance of broiler chicks.

The goal of this study was to determine the effects of feeding a zinc (Zn) deficient diet to broiler chicks for 96 h post-hatch followed by feeding diets with different Zn sources and supplemental levels (5 to 21 d) on the growth performance, tissue, and excreta Zn content. At the start of the study, four hundred 20-day-old male broiler chicks were divided into two groups. One group was fed a corn soybean meal based diet containing 25 mg of Zn/kg (imprinting diet, ID). The second group was fed the basal diet supplemented with 40 mg of Zn/kg from Zn oxide (ZnO) (non-imprinting diet, NID). Both groups were fed these diets for 96 h. At d 5, chicks from each group were randomly assigned to the dietary treatments consisting of the basal diet alone or the basal diet supplemented with 8 or 40 mg/kg Zn as ZnO or Zn proteinate. Main effects of post-hatch Zn ID were observed on feed intake and G:F. ID decreased (P < 0.05) feed intake and improved (P < 0.05) the gain to feed ratio (G:F) of 14 and 21 d old chicks compared to G:F of chicks fed NID. Additionally, G:F for 14 and 21 d was improved (P < 0.05) by interaction of Zn source × level. Furthermore, at d 21 chicks fed the ID had a lower (P < 0.05) Zn content in the tibia ash and excreta, and a higher (P < 0.05) Zn content in the pancreas tissue compared to chicks fed NID. These results suggest that Zn imprinting can affect body Zn stores and early performance.

A 60‐day feeding trial was conducted to evaluate the effect of dietary protein level on growth, digestive enzymes and haemato‐biochemical responses of Penaeus vannamei juveniles in inland ground saline water (IGSW) of 15 ppt salinity. The acclimated shrimp (avge. wt., 4.03 ± 0.05 g) were randomly distributed into seven groups, viz. TCP20, TCP25, TCP30, TCP35, TCP40, TCP45 and TCP50, in triplicate with the stocking density of 15 shrimp per tank (275 L). Seven semi‐purified hetero‐nitrogenous (200–500 g crude protein/kg), iso‐caloric (396 Kcal DE/100 g) and iso‐lipidic (60 g/kg) diets were prepared for feeding the shrimp of respective group four times daily on satiation basis. Results indicated that the highest (p < 0.05) WG and SGR, and the lowest FCR were observed in TCP40 group. But PER and ANPU values decreased significantly (p < 0.05) with increasing dietary protein. Whole‐body protein and ash contents varied significantly (p < 0.05) with an inverse relationship. Shrimps of TCP40 group had the highest (p < 0.05) haemocyanin and serum total protein, while TCP20 group showed the highest (p < 0.05) serum glucose. Serum cholesterol and triglyceride increased significantly (p < 0.05) with increasing dietary protein level up to 400 g protein/kg and beyond that these decreased gradually. Protease activity increased with increasing dietary protein level, but amylase activity showed an inverse trend. Second‐order polynomial regression analysis in relation to WG, SGR and FCR indicated that 393.0–397.90 g protein/kg diet could be optimum for culture of P. vannamei juveniles in IGSW of 15 ppt salinity.

The effects of manganese (Mn) preconditioning, 96 h post-hatch followed by the replacement of inorganic Mn with different levels of organic Mn (5 to 21 D), on growth, tissue excreta Mn content, gene expression, and enzyme activity were evaluated. A total of 420 day-old male Cobb 500 broilers were divided into 2 groups. One group was fed a corn–soybean meal basal diet containing 17 mg of Mn/kg (preconditioning diet, MnPD); the second group was fed the non-preconditioning diet (NPCD), which was the MnPD supplemented with 60 mg of Mn/kg from manganese sulfate (MnSO 4 ). On day 5, each group was divided into 5 subgroups and were randomly assigned to dietary treatments consisting of MnPD alone or MnPD supplemented with 12 or 60 mg Mn/kg Mn as MnSO 4 or Mn proteinate (6 replicate cages of 6 birds). Broiler chicks that were fed the MnPD had lower ( P ≤ 0.05) body weight gain (BWG) and G:F ratio when compared to those that were fed the NPCD for 4 D. Birds that were fed MnPD (1 to 4 D) and switched to MnPD supplemented with 60 mg/kg Mn (5 to 21 D) had lower ( P ≤ 0.05) BWG compared to those that were fed NPCD (1 to 4 D) and switched to MnPD supplemented with 60 mg/kg Mn for 21 D. Excreta, tibia ash, liver, and heart Mn levels were increased ( P ≤ 0.05) by supplemental Mn. The expression of jejunum divalent metal transporter-1 mRNA levels, as well as activities of plasma total super oxide dismutase and liver alanine transaminase, was not affected by MnPD or Mn source and levels. These results confirmed that feeding marginally deficient Mn diets to broiler chicks post-hatch does affect growth rate and tissue Mn concentration.

A feeding trial was performed for 60 days to determine the dietary lipid requirement of Penaeus vannamei juveniles reared in inland saline water (ISW) of 10 g/L salinity. Six iso-nitrogenous (360 g/kg crude protein) and heterocaloric (15.4-17.6 KJ DE/g) semipurified diets were prepared with graded level of lipid viz., 20, 40, 60, 80, 100 and 120 g/kg (L2-L12 with 20 g/kg incremental level). Two hundred and seventy P. vannamei juveniles (5.51 ± 0.01 g) were randomly allocated (15 shrimps/200 L) into six treatment groups in triplicate following a completely randomized design. The shrimp of L4 and L6 groups exhibited significantly higher per cent weight gain (WG%), specific growth rate and protein efficiency ratio and the lowest feed conversion ratio.The lipid efficiency ratio and hepatopancreatic somatic index were significantly decreased and increased with increasing levels of lipid respectively. The L6, L8 and L10 groups exhibited significantly higher (p < .05) lipase activity. Shrimp of higher dietary lipid fed groups exhibited significantly higher (p < .05) aminotransferase activity than their lower dietary lipid fed counterparts. Based on WG% data, broken-line linear and second-order polynomial regression analysis showed that the optimal dietary lipid requirement of P. vannamei in ISW of 10 g/L salinity was 46.5 and 51.4 g/kg respectively.

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Aim: The present study was conducted to optimize the dietary protein level in the diet of Genetically Improved Farmed Tilapia reared in inland ground saline water (IGSW) of 15 ppt ambient salinity. Methodology: Seven iso-caloric (400 kcal digestible energy, DE/100g), iso-lipidic (6%) and hetero-nitrogenous (20-50% crude protein, CP) purified diets were prepared for conducting the feeding trial. Following completely randomized design, the random distribution of 315 acclimatized fish (average body weight 4.01±0.01g) was made in seven groups namely, CP20, CP25, CP30, CP35, CP40, CP45 and CP50 in triplicate with the stocking density of 15 fish per replicate tank. Results: Weight gain percentage, specific growth rate, and expression of insulin like growth factor-I and insulin like growth factor-I receptor with higher quadratic relation (R2=0.94, 0.96, 0.90 and 0.93, respectively) to the dietary crude protein (CP) level significantly increased (p<0.05) up to 40% crude protein and beyond that the values significantly decreased. With higher quadratic (R2=0.83) relation, muscle RNA/DNA ratio was significantly highest in 40% crude protein fed group. With higher quadratic (R2=0.81 and 0.98, respectively) relations, significantly higher protease and lower amylase activities were found in 40, 45 and 50% crude protein fed groups. Interpretation: Second order polynomial regression analysis based on WG%, SGR and IGF-I gene expression revealed that the optimum dietary protein for GIFT juveniles could be 41.84, 40.66 and 42.22%, respectively. This data will be helpful for development of economic and environment-friendly feed for GIFT tilapia culture in inland ground saline water of medium salinity.