46 Indian J. Fish., 64 (Special Issue): 46-55, 2017 DOI: 10.21077/ijf.2017.64.special-issue.76198-07 Growth performance, body composition and fatty acid profle of liver and muscle in tilapia, Oreochromis mossambicus (Peters, 1852) fed algal meal incorporated diets S. K. PATRA, K. MISHRA, B. PATRO, K. SAMANTARAY, B. K. KHUNTIA, B. SAHU AND M. K. TRIPATHY College of Fisheries, Orissa Univeristy of Agriculture and Technology, Rangeilunda, Berhampur - 760 007 Odisha, India e-mail: ksamantaray@yahoo.com ABSTRACT The present study was conducted to evaluate the efect of algal meal incorporated diets on the growth performance and fatty acid profle 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 prolifca (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 sunfower 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 fnd out their suitability for culture of tilapia fngerlings. The fsh (av. wt. 2.8 ± 0.4 g) were fed up to satiation for 56 days at 28±2 0 C. Signifcant (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 efciency ratio (PER) and specifc growth rate (SGR) while AMM diet showed least efciency. 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 fsh fed with WS emphasised the benefts of its use as dietary ingredients for tilapia. The results clearly indicated that algae like AN and SP incorporated in tilapia diet signifcantly enhance growth and carcass protein, whereas WS helps to improve the levels of the essential n-3 fatty acids (EPA and DHA). Keywords: Algal meal diets, Fatty acid profle, Growth, Oreochromis mossambicus, Tilapia Introduction Tilapia is the second most important group of farmed fsh after carps worldwide. Global tilapia production estimated at 4.5 million t in 2012, was predicted to exceed 4.8 million t in 2014 (@ 6% growth) (FAO, 2014). Their hardiness and adaptability to a wide range of culture systems has led to the commercialisation of tilapia production in more than 100 countries. In comparison to freshwater fshes, the popularity of marine species as a healthy food commodity has increased tremendously, due to their higher content of n-3 fatty acids like eicosapentaenoic acid (EPA) (20:5n3) and docosahexaenoic acid (DHA) (22:6n3). In marine environment, fsh consume marine algae that are rich in n-3 fatty acids. It has been reported that dietary modulations can improve the levels of such fatty acids in the tissues of freshwater fsh, so as to provide healthy diet for human beings (Stefens, 1997). The growth of fsh depends both on protein and lipid levels as lipid has protein sparing efect. Fish mobilises saturated and monoenoic fatty acid as source of energy and retains polyunsaturated fatty acids (PUFA) in the body (Stefens, 1997). It has been confrmed that inclusion of algae in the diet signifcantly improves growth rate in red sea bream (Mustafa et al., 1995) and common carp (Oramary et al., 2016). On the other hand, the defciency of dietary PUFA has been reported to afect body compositional changes in fsh (Lund et al., 2014). Growth performance and lipid metabolism was studied in Atlantic salmon (Salmo salar) using two algae derived products Verdemin (derived from Ulva ohnoi) and Rosamin (derived from diatom Entomoneis spp.) replacing fsh meal (Norambuena et al., 2015). Hepher et al. (1978) pointed out that as methods of algal culture and harvesting