Comparative effects of probiotic bacteria, Lactobacillus pentosus and Lactobacillus plantarum, on growth factors and digestive enzymes activities in rainbow trout (Onchorynchus mykiss)

In recent years, use of probiotics has increased in aquaculture to improve the immunity and resistance to diseases in fish. In this study, two bacteria with probiotic ability, Lactobacillus pentosus and Lactobacillus plantarum, added to rainbow trout feeding during 60 days. Also a control group without administration of probiotic were selected. At the end of this period, the growth and digestive enzymes of fish were studied. After 60 days, the fish fed the diet containing probiotic show significantly improved specific growth ratio (SGR), protein efficiency rate (PER) and body weight gain (BWG) (p<0.05). The Food conversion ratio (FCR) was significantly higher in the control group than in the other two groups (p<0.05). At the end of this period, lipase, amylase and trypsin showed a significant increas in comparison to the control group (p<0.05), however alkaline phosphatase and protease had no significant differences as compared with control (p>0.05). It can be cocluded that the use of Lactobacillus pentosus and Lactobacillus plantarum distinctly affect on improvement of growth and digestive enzymes and they can be helpful in digestion of feeding ingredients in rainbow trout.