Feed represents the single largest input in commercial aquaculture comprising about 60% of the total operating cost (De Silva & Anderson, 1995). The present requirement of aquafeed is estimated to be 60 million tonnes (FAO, 2014). Presently, both protein and energy rich conventional dietary ingredients are of short supply which necessitates incorporating unexplored unconventional locally available ingredients in aquafeed. Oil cakes are conventional protein sources used for carp culture in Asia along with deoiled rice bran (DORB), which is predominantly used in aquafeeds (Meshram, Deo, Kumar, Aklakur, & Sahu, 2018). DORB is an agricultural by-product, which is the most common ingredient used with oil cake. This is a cheap source in aquafeed, which is available throughout the year (Veerina, Nandeesha, & Gopal Rao, 1993).In the recent past, it is observed that the price and utilization of

A 90‐day experiment was conducted on Common Carp Cyprinus carpio in eight rectangular earthen ponds (21 × 10 × 1.50 m) for testing the effect of four groundwater salinities (0, 5, 10, and 15‰). At the end of the experiment, 100% survival was observed in all of the treatment groups. Somatic growth and reproductive performance were significantly (P < 0.05) influenced by salinity. Both males and females showed a significantly higher gonadosomatic index (24.46 ± 4.11% [mean ± SE]) at 5‰ (P < 0.05) compared with the fish that were kept in freshwater (15.92 ± 2.43%). The gonadal osmolality and osmolytes of the seminal and ovarian fluids increased in proportion to salinity. Ova diameter was inversely related to salinity. The incidence of spawning at 5‰ was significantly higher than at 0, 10, and 15‰. The gonadosomatic index was also significantly higher (30.15 ± 3.44%) at 5‰ followed by 0, 10, and 15‰, respectively. We concluded that the optimum salinity for the maturation of Common Carp is 5‰.

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A 60‐d experimental trial was conducted to evaluate the effects of alternative feeding, restriction feeding, and refeeding on digestive enzymes, metabolic enzymes, and metabolites in Rohu Labeo rohita fingerlings. Fish weighing around 13 ± 2 g were randomly distributed into four treatment groups and a control group. The control group was fed with 3% body mass twice a day throughout the experiment. The four treatment groups consisted of T1 (alternate day feeding), T2 (0.5% feeding), T3 (1% feeding), and T4 (2% feeding). The fish were fed for the first 30 d according to the feeding schedule, and from day 31 onwards all of the treatment groups were fed the same rations as were the control fish up to 60 d. The samples were collected on days 0, 15, 30, 45, and 60 of the experimental trial. The activity of digestive enzymes decreased significantly (P < 0.05) in T1, T2, and T3 with respect to the control, and the lowest activities were found on day 30 of the experiment. The glucose‐6‐phospahate dehydrogenase activity decreased with the level of restriction feeding, with the lowest activity occurring at day 30 in the T2 group, and it improved with refeeding. The serum glucose, triglycerides, and cholesterol concentrations decreased, with the lowest levels occurring in the T2 group at day 30. The current study revealed that restriction feeding and refeeding affected the digestion and metabolism of Rohu fingerlings within a short period of 30 d, and refeeding restored the optimum activity levels within the same 30‐d period thereafter.

The study was conducted to investigate the productivity and profitability of broiler on L-methionine supplemented diet. A total of 160 day-old broiler chicks (Cobb 500) was randomly distributed to four dietary supplements, D0 (Control), D1 (0.30 % L-Met), D2 (0.35 % L- Met) and D3 (0.40 % L- Met). Each treatment was replicated five times with 8 birds per cage. The chicks were reared in the battery cages while they were fed with broiler starter diet (crumble) until Day14 of age. The birds with fed with L-Met supplemented diets starting from Day15 until Day35 of age All the diets were iso-caloric and iso-nitrogenous.. Results revealed that the L-Met supplementations were in favor of higher live weight (LW) and better (p<0.05) feed conversion ratio without affecting the feed intake (FI). The D3 diet resulted higher (p<0.01) LW in the birds than all others on Day35 of age. The livability (%) was unaffected (p>0.05) by the dietary supplements. No significant (p>0.05) difference was observed in the relative weights of visceral organs (small intestine, proventriculus, gizzard, liver and heart) except for the spleen. Relatively increased (p<0.05) spleen weight (%) was observed in the D3 diet. The breast weight (%) was increased marginally (p<0.07) in the D3 group, while the other carcass parts; breast weight, thigh weight, wing weight, shank weight, drumstick weight, neck weight, and abdominal fat content were found to be similar (p>0.05) in the dietary groups. Higher profit (p<0.01) and lower production cost (p<0.05) were observed in the D3 group than that of the others. It can be inferred that 0.40% L-Met supplementation in the broiler diet is better for growth performance and profitability. Bang. J. Livs. Res. Vol. 27 (1&2), 2020: P. 1-14