THE EFFECT OF PROBIOTIC DIET ON GROWTH AND HEMATOLOGY PARAMETERS OF RAINBOW TROUT (ONCORHYNCHUS MYKISS, WALBAUM 1792)
Mirela Mocanu (Creţu), V. Cristea, Lorena Dediu, Elena Bocioc, Rodica Iulia Grecu, Sandiţa (Plăcintă) Ion, I. Vasilean
This study was undertaken to examine the effect of dietary probiotics on rainbow trout, based on growth performance and hematological profile. The 2 species of endospore bacillus, B. licheniformis and B. subtilis, as a blend of probiotic bacteria, were employed in 3 concentrations for diet supplementation (V1:22.4x109, V2:38.4x109 and V3: 70.4x109 CFU g-1). The effects were compared with those of control diet, containing no probiotic. The trout with initial mean body weight of 101.96 ± 2.26 g was fed with 3 percentage of their body weight, 3 times per day. After feeding with supplemented diets for 4 weeks, growth performance, feed utilization and health status were assessed. The comercial probiotic mixture showed an improvement of feed conversion ratio (FCR), specific growth rate (SGR) and protein efficiency ratio (PER) at concentration of 22.4x109 CFUg-1. The hematological indices (hemoglobin, red blood cells and hematocrit) showed differences among experimenatal variants. In the present study a higher levels of probiotics does not correlates with the best results in terms of growth and physiological status. Thus is demonstrated that the appropriate doze of probiotic should be established before application in intensive aquaculture in order to prevent any unwanted effects.
Key words: probiotic, growth performance, hematology indices, recirculating aquaculture