A 45-days feeding trial was conducted to study the immunomodulatory effect and interferon gamma gene expression of dietary fucoidan rich seaweed extract (FRSE) from Sargassum wightii on Pangasianodon hypophthalmus fingerlings. One hundred and eighty fingerlings were distributed into six experimental groups in triplicates. Each group was stocked with 10 fish and fed to satiation with iso-nitrogenous (34.96 AE 0.09-35.18 AE 0.03 CP%) and iso-caloric (368.65 AE 0.86-375.09 AE 0.26 Kcal/100 g) purified diets containing either 0% FRSE (control), 1% FRSE (TF 1 ), 2% FRSE (TF 2 ), 3% FRSE (TF 3 ), 3% seaweed powder (TS 3 ) or 6% seaweed powder (TS 6 ) in the feed. After feeding trial the experimental fish were challenged with Aeromonas hydrophila. Immunological parameters like respiratory burst activity, lysozyme activity, phagocytic activity and total leukocyte count (TLC) were increased with the increasing level of dietary FRSE, whereas serum Albumin/ Globulin (A/G) ratio and blood glucose level exhibited decreasing trend (P < 0.05). Increased TLC, blood glucose level, respiratory burst activity, serum A/G ratio, lysozyme and phagocytic activities were recorded during the post-challenge period. Maximum expression of interferon gamma (IFN-c) gene was recorded in FRSE fed groups than the control group both in pre and post challenge condition. After challenged with A. hydrophila the highest survival was observed in TF 2 and TF 3 groups whereas lowest survival was observed in the control group. Hence, dietary supplementation of FRSE at an optimum level of 2% reduced the stress and improved the immune status of P. hypophthalmus fingerlings.

A 12-week feeding trial was conducted to quantify the dietary lysine requirement of juvenile silver pompano with an initial average weight of 6.28 g reared in indoor recirculatory system. Six treatment diets were designed with isonitrogenous, isolipidic and isoenergetic diets. (42% CP, 6% CL and 4.28 kcal g −1 GE) were formulated with graded levels of lysine (1.52, 1.85, 2.21, 2.49, 2.74 and 2.98 g/100 g, dry diet). Equal amino acid nitrogen was maintained by replacing lysine with nonessential amino acid mixture. Fish were randomly stocked, in triplicate groups, in 180 L indoor glass rectangular tanks with recirculatory system and fed to apparent satiation over two feedings at 10:00 and 16:00 h daily during the experimental period. The results indicated that there were significant differences in growth and feed utilization among the treatments. Fish fed diets with lysine in different treatments showed high survival rate (95-100%). Maximum weight gain (WG), specific growth rate (SGR) and protein efficiency ratio (PER) occurred at 2.21% dietary lysine. The hepatosomatic index (HSI), viscerosomatic index (VSI) and crude protein content in whole body were significantly affected by dietary lysine levels. There were significant differences (P < .05) in total serum protein levels and erythrocyte count in fish fed diets with different dietary lysine levels. No significant differences were observed in the levels of serum glucose, triglycerides and creatinine levels among the treatments. In the present study, optimization of fitted quadratic regression of weight gain%, SGR, PER and FER on lysine in diet revealed that the optimum lysine requirement of silver pompano was in the range of 2.40-2.45% of dry diet (5.71-5.83% of dietary crude protein).

a b s t r a c tThe nutritional potential of protein isolate from rubber seed (RPI) in the diets of Labeo rohita (initial average weight 4.45 ± 0.01 g) was assessed in a 60 days feeding trial. Five isonitrogenous (32.62 ± 0.13 CP Kg −1 ) and isocaloric (18.47 ± 0.08 MJ kg −1 ) experimental diets were formulated with graded level of RPI like 0%, 25%, 50%, 75%, or 100% in replacement for soybean protein isolate (SPI), and designated as Control, RPI25, RPI50, RPI75, RPI100, respectively. The RPI contributed 0%, 13%, 26%, 39% or 52% of the total dietary protein in the diets. Each diets were randomly assigned to 15 experimental tanks containing 12 fish in triplicates and fed to satiation twice daily at 10:00 h and 18:00 h. At the end of the feeding trial, the growth performance and nutrient utilization indices such as percent weight gain (WG%), specific growth rate (SGR), daily growth coefficient (DGC), feed intake (FI), protein efficiency ratio (PER), feed conversion ratio (FCR) and protein retention (PR) values were not significantly (p > 0.05) affected by the dietary treatments irrespective of inclusion levels of RPI. A significantly higher (p < 0.05) hepatosomatic index (HSI) was recorded in the control and RPI 50 group compared to other treatment groups (p < 0.05). The intestinal somatic index (ISI) and Survival rate were similar (p > 0.05) in all the groups. The apparent digestibility coefficients (ADCs) of dry matter and protein for fish fed the control and RPI 100 diets were found to be similar, while RPI 50 and RPI 75 groups exhibited a significantly lower value corresponding to the protease enzyme activity. The whole body compositions and digestive/metabolic enzymes activities among the various groups did not differ significantly (p > 0.05). The serum cholesterol and triglyceride levels were found to be significantly higher (p < 0.05) in the control compared to the RPI fed groups. Significantly higher serum glucose level was recorded in RPI 50, while a reverse was seen in the liver glycogen contents. Overall, this study clearly showed that RPI from rubber seed can serve as alternative protein source in the diets of L. rohita fingerlings without any adverse effects on growth, nutrient utilization and physio-metabolic responses.

No abstract

No abstract