Production of bacterial probiotic from trout (Oncorhynchus mykiss) for improvment of immune system and challenge to streptococcusis

Abstract

This study was conducted for the first time and the effects of probiotic bacteria isolated from the gut of Rainbow trout (Oncorhynchus mykiss). In the first step, after the purification of the isolated bacteria, probiotic properties in vitro was assessed with injection to healthy fish and challenge with three species of pathogenic bacteria in culture media. The second phase of the bacteria isolated in 5 treatments (log 7, 8 and 9 of the lactic bacteria (LAB), Vibrio sp and Pseudomonas sp) and a control treatment on growth and survival, hematological parameters (RBC and WBC cells), immunology and physiology parameters tested during the 60 days of the above parameters after 30 and 60 days and finally at the end, the final assessment was Streptococcosis resistance in fish. The results showed that the isolated bacteria were able to enhance the growth parameters (weight, feed conversion, feed fat, protein efficiency ratio and specific growth rate) and survival. The results showed that log 8 LAB was significant difference with other treatments and control. When using log 8 LAB and Vibrio, the MCV, MCH and MCHC were decreased with no significant difference. The log 8 has the greatest effect on the amount of liver enzyme (AST), IgM and complement component C3, and had significant difference with other treatments. The challenge examination to Streptococcus iniae showed the highest survival in treatments with log 8 (96.66%), and Vibrio (93.33%) and then subjected to other treatments and control are also the least survival (25.38%). The conclusion of that study is the first probiotic properties of bacteria isolated from trout to changes in quality indicators are in particular the LAB bacteria and the second log 8 of LAB had significant positive of changes development and safety, and the fish are resistanted against Streptococcosis.