Effect of a multi-strain probiotic (Primalac) on growth performance, some blood biochemical parameters, survival and stress resistance on Caspian kutum (Rutilus kutum) fry

This study was conducted to evaluate the effect of probiotic supplementation of Primalac on growth performance، some blood biochemical parameters، survival and salinity tolerance of the Caspian kutum fry. Fish (1. 002±0. 001 g) were classified to four groups fed on diets containing Primalac in different levels: 0 (control)، 0. 05، 0. 10 and 0. 15 % for 45 days. The results showed that there was a significant increase in final weight، weight gain and specific growth rate in those fish fed 0. 10% Primalac diets (p<0. 05). In addition، food conversion ratio of fish fed Primalac diets was significantly (p<0. 05) lower than those fed the control group. However، there was no significant differences in condition factor، blood glucose and blood total protein content between fish fed different experimental diets (p>0. 05). On the other hand، blood cholesterol of the Caspian kutum was significantly increased in control group in comparison with Primalac treatments (p<0. 05). Survival and tolerance to salinity stress challenge remained unaffected by dietary supplementation of Primalac (p>0. 05). The results of the present study indicate that the supplement of 0. 10% Primalac have a positive effect on the growth performance and blood biochemical parameters of the Caspian kutum fry.