Study of Pediococcus pentosaceus effect on histomorphometrical structure of intestine in juvenile rainbow trout (Oncorhynchus mykiss Walbaum, 1792)

In recent decades, many studies have been conducted evaluating the effects of probiotics in fish. Its positive effects on growth performance and the health of fish have been reported. Rainbow trout is one of the aquaculture species which is important in economic aspect. Juvenile rainbow trout were used in one control group (without bacteria in food) and three treatment groups with108 CFU/g Pediococcus pentosaceus in different doses of 200,300,400 g/ 1000 kg food were used in this study. After eight weeks, tissue samples from different parts of the intestine have been taken and then fixed in 10 % formalin. Then, tissue passages were stained with hematoxylin-eosin, and Masson’s trichrome. The results showed that histometrical values like height and width of the villi in anterior and middle intestine of treatment groups especially in 400 g bacteria / 1000 kg food was significantly (p