No abstract

Two experimental diets, containing 35% crude protein (P35) and 1628.4 kJ digestible energy and 45% crude protein (P45) and 2088.8 kJ digestible energy with protein to energy (P/E) ratio of 21.5 mg protein kJ -1 in both diets, were fed at incremental rates (1.0, 1.5, 2.0, 2.5, 3.0, 4.0 and 5.0% of body weight day -1 (Bw.d -1 ) to murrel (Channa striata) fingerlings for 8 weeks. A linear increase in growth rate of fingerlings was observed up to 10.5 g protein (kg Bw.d) -1 and 488.51 kJ energy (kg Bw.d) -1 in P35 diet (r 2 =0.83) and 11.25 g protein (kg Bw.d) -1 and 522.2 kJ energy (kg Bw.d -1 ) in P 45 diet (r 2 =0.89). Regressing growth rate obtained for both the diets to zero weight gain, resulted in a maintenance requirement of 0.3 g protein (kg Bw.d) -1 and 16.6 kJ energy (kg Bw.d -1 ). The net gain in body protein also increased linearly with increasing feeding rates up to 10.5 g protein (kg Bw.d) -1 and 488.51 kJ energy (kg Bw.d) -1 in P35 (r 2 =0.74) and 11.25 g protein (kg Bw.d -1 ) and 521.99 kJ energy (kg Bw. d) -1 in P45 (r 2 =0.4). Regression equations from the data obtained with the P35 diet predicted that 1.58 g protein (kg Bw.d) -1 and 71.4 kJ energy (kg Bw.d) -1 was required to maintain a constant amount of tissue protein in fingerlings. But with P45, the protein and energy intake levels have insignificant effects on carcass protein. The ration maximum (R max ) values for growth were calculated to be 13.4 to 14.7 g protein (kg Bw.d) -1 and 666.6 kJ energy (kg Bw. d) -1 in both diets which corresponded to growth maximum (G max ) of 1.18 to 1.28% wt d -1 for protein and 1.24 to 1.26% wt. d -1 for energy. The R max value for body protein deposition was calculated to be 11.8 g protein (kg Bw.d) -1 and 571.4 kJ energy (kg Bw.d) -1 with a predicted protein maximum (P max ) of 1.62 to 1.72% with P35 diet. The effect of feeding rate on feed, protein and energy conversion efficiency and proximate composition were also examined.

Abstract-Fish hydrolysate (FH) based

No abstract

The present study was conducted to evaluate the effect of algal meal incorporated diets on the growth performance and fatty acid profile of tilapia Oreochromis mossambicus (Peters, 1852). Control diet (Diet 1) for the study was formulated with rice bran, groundnut oil cake (GNOC) and soybean meal. Six iso-energetic and iso-nitrogenous test diets (Diets 2 to 7) were prepared by incorporating (@40%) one of the four microalgae viz., Anabaena cylindrical (AN; Nostoc salbasa (NS); Spirulina platensis (SP) and Westiellopsis prolifica (WS) or with an algal meal mixture containing the above four algae plus the macroalgal species viz., Gracilaria edulis (GE) and Enteromorpha intestinalis (EI) mixed in equal proportions along with sunflower oil and cod liver oil (by totally replacing rice bran, GNOC and soyabean meal of the control diet) (AMM+O diet, Diet 6) and AMM without addition of oils served as AMM diet (Diet 7). The algal meal supplemented diets were tested against a control diet to find out their suitability for culture of tilapia fingerlings. The fish (av. wt. 2.8 ± 0.4 g) were fed up to satiation for 56 days at 28±2 0 C. Significant (p<0.05) enhancement in growth was observed with AN (565.2%) diet followed by SP (500%) and WS (400%) compared to control (402.3%). The AN diet showed best performance in terms of feed conversion ratio (FCR), protein efficiency ratio (PER) and specific growth rate (SGR) while AMM diet showed least efficiency. Fish fed with SP diet showed better apparent net protein utilisation (ANPU%) as compared to other diets. Saturated fatty acid (SFA) in the liver and muscle decreased while monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids increased over their respective initial values in all the dietary groups except in groups fed with AMM+O and AMM. The n-6 level of liver and muscle increased with SP diets. Substantial increase in docosahexaenoic acid (DHA, 22:6n3) and eicosapentaenoic acid (EPA, 20:5n3) in fish fed with WS emphasised the benefits of its use as dietary ingredients for tilapia. The results clearly indicated that algae like AN and SP incorporated in tilapia diet significantly enhance growth and carcass protein, whereas WS helps to improve the levels of the essential n-3 fatty acids (EPA and DHA).