Indian Journal of Animal Research 586 RESEARCH ARTICLE Indian Journal of Animal Research, Volume 57 Issue 5: 586-591 (May 2023) Effect of Dietary Lipid Sources and Their Combinations on Growth and Fatty Acid Composition of Milkfish ( Chanos chanos ) Larvae T. Sivaramakrishnan 1,2 , K. Ambasankar 2 , N. Felix 3 , K.P. Sandeep 2 , Aritra Bera 2 , E. Suresh 1 , Biju Sam Kamalam 4 , M. Kailasam 2 , S.A. Shanmugam 1 10.18805/IJAR.B-5072 ABSTRACT Background: The success of larval rearing is greatly influenced by first feeding regimes and the nutritional quality of weaning diets, with dietary lipids being recognized as one of the most important nutritional factors that affect larval growth and survival. Reports are scanty on milkfish larval nutrition and growth and survival unlike other marine species. Methods: In this investigation during 2020, five larval diets were prepared with 40 g kg -1 of entirely fish oil (F4), corn oil (C4) or fish oil and corn oil in 3:1 (F3C1), 2:2 (F2C2) and 1:3 (F1C3) ratios. Each diet was fed to triplicate groups of milkfish larvae (45 mg) in a flow-through rearing system for 42 days. Result: A growth indices were highest in the F3C1 group, followed by F2C2, F4 and other dietary treatments. The whole-body fatty acid profile was found to change significantly with increasing fish oil replacement with corn oil, i.e., the n-3 polyunsaturated and saturated fatty acid proportions decreased linearly, while the n-6 polyunsaturated fatty acids content increased. Overall, this study reveals that growth and survival of milkfish is dependent on dietary lipid source or combinations that meet the essential fatty acid requirements during the early life stages. Key words: Corn oil, Essential fatty acids, Fish oil, Larval nutrition, Lipid, Milkfish. INTRODUCTION Lipids play an important role in the larval nutrition of fish, as they supply the required quantities of energy and essential fatty acids (Borlongan, 1992; Sargent et al., 1999; Izquierdo et al., 2000). Especially in marine fishes, the n-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA), namely eicosapentaenoic acid (EPA, 20:5 n-3) and docosah exaenoic acid (DHA, 22:6 n-3), are essential to maintain the structure, fluidity and function of cell membrane permeability and plasticity and also to support prostaglandin production and other essential physiological functions (Tocher, 2003; Faulk and Holt, 2005; Sivaramakrishnan et al., 2017). However, in recent years, plant oil sources are widely used to partially replace fish oil in finfish feeds, as they are abundant, less expensive and free of dioxins and other organic pollutants (Torstensen et al., 2000; Bell et al., 2001; Montero et al., 2003). Several studies have shown that changes in the dietary fatty acid profile and unsaturated fatty acid concentration (e.g., when fish oil is replaced with vegetable oil) influence fatty acid composition and zootechnical indices of animal (Montero et al., 2003; Bransden et al., 2003; Mourente et al., 2005; Lin and Shiau, 2007). For instance, corn oil contains relatively large quantities of n-6 PUFAs such as linoleic acid (18:2 n-6); whereas, n-3 PUFA is rich in fish oil (Bell et al., 2001). The effect of corn oil as a dietary lipid source in juvenile grouper reported that increasing growth and immune responses in partially corn oil replaced diets but decreasing when fish oil was completely substituted (Lin and Shiau, 2007). The choice of corn oil to substitute fish oil in milkfish larval diets in this study was made because of its favourable fatty acid profile and high content of natural antioxidants (vitamin E) and phytosterols (Moreau, 2011). Milkfish is an important brackishwater food fish cultured in the Indo-Pacific region, with bulk of the production coming from Philippines, Indonesia, Taiwan and other south-east Asian countries (Lim et al., 2002; Bera et al., 2021). The amenability of this fish species for culture in fresh, brackish and marine waters makes it more potential candidate species. Globally, it is one among the top twenty aquaculture 1 Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Institute of Fisheries Post Graduate Studies, Vaniyanchavadi, Chennai-603 103, Tamil Nadu, india. 2 ICAR-Central Institute of Brackishwater Aquaculture, Chennai-603 103, Tamil Nadu, india. 3 Tamil Nadu Dr. J. Jayalalitha Fisheries University, Vettar River View Campus, Nagapattinam-611 002, Tamil Nadu, India. 4 ICAR- Directorate of Coldwater Fisheries Research, Bhimtal-263 136, Nainital, Uttarakhand, India. Corresponding Author: T. Sivaramakrishnan, ICAR-Central Institute of Brackishwater Aquaculture, Chennai-603 103, Tamil Nadu, india. Email: sivaraman.fish@gmail.com How to cite this article: Sivaramakrishnan, T., Ambasankar, K., Felix, N., Sandeep, K.P., Bera, A., Suresh, E., Kamalam, B.S., Kailasam, M. and Shanmugam, S.A. (2023). Effect of Dietary Lipid Sources and Their Combinations on Growth and Fatty Acid Composition of Milkfish (Chanos chanos) Larvae. Indian Journal of Animal Research. 57(5): 586-591. doi: 10.18805/IJAR.B-5072. Submitted: 13-12-2022 Accepted: 10-01-2023 Online: 27-01-2023