Effect of Increasing Dietary Prebiotic GroBiotic®-A Concentration on Growth Performance, Body Indices and Haematological Parameters in Rainbow Trout (Oncorhynchus mykiss) Fingerling

An ۸۴-day feeding trial was carried out onfingerling (۴.۴۴ ± ۰.۰۶ g) rainbow trout (Oncorhynchusmykiss, Walbaum, ۱۷۹۲) to evaluate the effect of dietary supplementation with a commercial prebiotic GroBiotic®-A (G-A) on the growth, feed efficiency, haematology and immunlogical parameters. Ttreatments containing various inclusions of G-A (۰ %, ۰.۵ %, ۱.۰ %, ۱.۵ %, ۲.۰ %, ۲.۵ %, and ۳.۰ %) were added to a commercial fish dietand were fed twice daily at ۲-۶ % of body weight. The highest weight gain (WG), specific growth rate (SGR) and average daily gain (ADG) were obtained in fish fed the diet containing ۲.۵ % G-A followed by ۳.۰ % inclusion (P<۰.۰۵). The highest feed efficiency (FE), protein efficiency ratio (PER) and net protein utilization (NPU) were also recorded in the ۲.۵ % G-A inclusion (P<۰.۰۵). Survival was significantly higher (P<۰.۰۵) in fish fed with ۲ % and ۲.۵ % G-Asupplement (P<۰.۰۵). Although higher Hb, haematocrit, RBC, WBC, MCH, MCHC, MCV, lymphocytes, and neutrophils were observed at all  G-A supplemented diets, the differences among themwerenot significant (P>۰.۰۵). On the other hand,significantly higher differencee (P<۰.۰۵) in lysozyme and immunoglobulin (IgM) concentrations wereobserved in ۲.۵% G-A inclusion. The results of this study indicated that ۲.۵ % G-A inclusionhad a better performance on growth and haematoimmunological parameters in rainbow trout fingerling.

کلیدواژه ها:

Feed efficiency ، fish ، Growth performance ، Oncorhynchus mykiss ، Prebiotic GroBiotic®-A