Dietary Lipid Levels Affect Growth and Fatty Acid Profiles of Malaysian Mahseer Tor tambroides

Abstract

AbstractAfter protein, the second major essential macronutrient in fish diet is lipid. This study was conducted to determine the optimum level of dietary lipid for the best growth performance of juvenile Malaysian mahseer Tor tambroides. Four isonitrogenous diets containing 40% crude protein were formulated to contain different levels of lipid (5, 10, 15, or 20% on an as‐fed basis). Cod liver oil was incorporated into the feed as the main dietary lipid source used to formulate the diets while residual oil coming from other ingredients contributed about 5% of dietary lipid. The experimental diets were labeled as L5, L10, L15, or L20 to denote the levels of dietary lipid. Fish were fed the experimental diets in triplicate groups for 63 d. Growth performance, survival rate, and daily feed intake by Malaysian mahseer significantly decreased when fed diets in which levels of dietary lipid increased from 5% to 20%. However, the growth performance did not vary significantly between fish fed the L5 and L10 diets. The increase in dietary lipid significantly increased the hepatosomatic index but did not influence the viscerosomatic index. Increasing dietary lipid levels also decreased the lipid content in the whole body composition of fish. The monounsaturated fatty acid (MUFA) and n‐3 polyunsaturated fatty acid (PUFA) contents of fish liver significantly increased with the increase of dietary lipid. The results of this study suggested that 5% dietary lipid is sufficient for the best survival rate and growth performance of juvenile Malaysian mahseer.