University of Guilan Aquatic Animals Nutrition 2980-8499 1 1 2015 03 21 The effect of probiotic Bacilli on feed efficiency and carcass quality of rainbow trout, Oncorhynchus mykiss fry The effect of probiotic Bacilli on feed efficiency and carcass quality of rainbow trout, Oncorhynchus mykiss fry 37 49 119 FA Hakimeh Sargazi Hojatollah Jafarian Journal Article 2014 11 11 In this study, the effects of probiotics bacilli on the feed efficiency and carcass quality in rainbow trout, <em>Oncorhynchus mykiss</em>, fries were studied using a commercial product Protexin Aquatech. A blend of five strains of probiotic bacilli (<em>Basilus licheniformis</em>,<em> B. subtilis</em>,<em> B. polymyxa, B. laterosporus </em>and<em> B. circulans</em>) was used through the supplementation of diets for 60 days. Fish fry with an average weight of 463 ± 32 mg were used. The experimental diets were supplemented with mixture of the five bacilli at concentrations of 1×10<sup>6 </sup>(D<sub>1</sub>) 1×10<sup>7 </sup>(D<sub>2</sub>) and 1×10<sup>8 </sup>(D<sub>3</sub>), (CFU per 100 g food), and a control (probiotics-free diet). The feeding rate was varied between 5 and 8% of body weight. The results indicated that D<sub>2</sub> treatment had significantly better growth and feed conversion ratio than the control group and D<sub>1 </sub>treatment. Results showed that in the experimental treatments, probiotics had a significant positive effect on protein efficiency ratio, lipid efficiency ratio and protein productive value compared to the control treatment (P<0.05). The dry matter, crude protein and crude lipid of fry carcass in D<sub>2 </sub>treatments, were significantly increased (P<0.05). The results showed that the probiotics bacilli increased feed efficiency and growth performance in rainbow trout fry. In this study, the effects of probiotics bacilli on the feed efficiency and carcass quality in rainbow trout, <em>Oncorhynchus mykiss</em>, fries were studied using a commercial product Protexin Aquatech. A blend of five strains of probiotic bacilli (<em>Basilus licheniformis</em>,<em> B. subtilis</em>,<em> B. polymyxa, B. laterosporus </em>and<em> B. circulans</em>) was used through the supplementation of diets for 60 days. Fish fry with an average weight of 463 ± 32 mg were used. The experimental diets were supplemented with mixture of the five bacilli at concentrations of 1×10<sup>6 </sup>(D<sub>1</sub>) 1×10<sup>7 </sup>(D<sub>2</sub>) and 1×10<sup>8 </sup>(D<sub>3</sub>), (CFU per 100 g food), and a control (probiotics-free diet). The feeding rate was varied between 5 and 8% of body weight. The results indicated that D<sub>2</sub> treatment had significantly better growth and feed conversion ratio than the control group and D<sub>1 </sub>treatment. Results showed that in the experimental treatments, probiotics had a significant positive effect on protein efficiency ratio, lipid efficiency ratio and protein productive value compared to the control treatment (P<0.05). The dry matter, crude protein and crude lipid of fry carcass in D<sub>2 </sub>treatments, were significantly increased (P<0.05). The results showed that the probiotics bacilli increased feed efficiency and growth performance in rainbow trout fry. Rainbow trout probiotic Supplementation Crude protein Growth Performance https://janb.guilan.ac.ir/article_119_0f875376250a57fa4d145070c16805ac.pdf