Effects of Lactococcus lactis and Weissella cibaria as probiotic on growth performance, intestinal bacterial flora, digestive enzymes and intestinal histology in common carp (Cyprinus carpio)

The aim of the present study was to investigate the effect of Lactococcus lactis and Weissella cibaria probiotics on growth performance, intestinal bacterial flora, digestive enzymes and intestinal histology in common carp (Cyprinus carpio). Fish with an average initial weight of 17 g were divided into 10 treatments with 3 replications. Fish food in treatments 1, 2 and 3 were supplemented with 29.9 × 10 10 CFUg-1 of Lactococcus lactis in doses of 150, 300 and 450 mgKg-1, food for treatments 4, 5 and 6 were supplemented with 22×10 10 CFUg-1 of Weissella cibaria in doses of 150, 300 and 450 mgKg-1, these two probiotics were equally mixed for food preparation to treatments 7,8 & 9 and used in doses of 150, 300 and 450 mgKg-1 as well as fish in treatment 10 (Control) feed basal diet with no probiotics. They were feed for 8 weeks. Fish weight and length were measured at the beginning and end of experiment to examine growth performance. Blood samples were collected to measure the amounts of digestive enzymes. Intestinal bacterial flora and intestinal histology were also performed. The results of the present study showed a significant increase in body weight gain, specific growth rate, average daily growth and a significant decrease in food conversion ratio in most treatments feed supplemented food compared to the control (P<0.05). Also, the lowest amount of amylase, lipase and protease enzymes was observed in the control. The number of lactic acid bacteria in fish feed with probiotic supplemented food was significantly higher than the control treatment (P<0.05). Finally, it was found that adding 300 mgkg-1 of combination of these probiotics and after that adding 300 mgkg-1 W.cibaria will improve growth performance, activity of digestive enzymes, intestinal microbial flora and lactic acid bacteria in common carp.