COMPARATIVE STUDY ON THE GROWTH, NUTRITIONAL COMPOSITION, PIGMENT AND HEMATO-BIOCHEMICAL INDEX OF NILE TILAPIA (Oreochromis niloticus) FRY FED WITH SELECTED MICROALGAE

Abstract

An 8-week feeding trail was conducted to evaluate the effects of two selected marine microalgae strain Nannochloropsis sp. and Tetraselmis sp. on growth performance, water quality, hemato-biochemical index, carotenoid concentration, nutrition and biochemical composition of Nile tilapia Oreochromis niloticus fry (initial weight 0.023±0.0001 g, mean ± SE). Treatments were designed with five experimental diets: CF (0% microalgae which is control feed), N25 (25% Nannochloropsis sp.), T25 (25% Tetraselmis sp.), N50 (50% Nannochloropsis sp.) and T50 (50% Tetraselmis sp.) respectively. Two hundred seventy Nile tilapia fry were randomly assigned in 15 rectangular experimental tanks in triplicate form of each treatment. To find the data of growth performance initial and final body weight was recorded. To check the survivality initial and final number of fish was counted. Physical parameters of water quality were checked daily and chemical analysis of water quality parameters were done weekly. At the end of 8-week experiment, fish were sampled for determination of total carotenoid concentration, hemato-biochemical parameters, proximate composition and fatty acid profile of whole Nile tilapia fish tissue and significant (p < 0.05) changes of values were observed. The results revealed that supplemented microalgae alone could not significantly enhanced the growth performance than control (p < 0.05). Low palatability and antinutritional factors may be responsible. Significant high survival, better TAN, NO2-N and SRP was noticed in T25 than control (p < 0.05). The hemato-biochemical parameters exhibited significant increase of certain parameters within reference range, however significant decrease in some blood parameters was noticed also (p < 0.05). Although higher percentage of microalgae in diet has reduced the protein concentration in whole fish muscle compared to control but high lipid and carbohydrate was recorded in N50 and T50 treatment respectively. Comparatively higher carotenoid concentration was revealed in N50 than control. Increasing dietary Nannochloropsis sp. and Tetraselmis sp. has also significantly (p < 0.05) increased the percentage of saturated fatty acids (SAFs), polyunsaturated fatty acids (C20:5n-3, C22:6n-3 etc.) compared to control. Thus, this study provides significant information about beneficial impacts of Nannochloropsis sp. and Tetraselmis sp. on Nile tilapia fish.