Efficacy of Lactobacillus acidophilus and yeast cell wall-derived supplements on immunity responses, growth performance, and disease resistance in Cyprinus carpio juveniles.

This study investigated the effects of probiotic Lactobacillus acidophilus (PTCC 1643) (LA) and a commercial yeast cell wall prebiotic (Immunogen^®) (IM) on immunoantioxidant, growth, and digestive status, and resistance to Aeromonas hydrophila in Cyprinus carpio juveniles. The fish were fed in five treatments including control (T1), LA1.5 (T2): 1.5 (× 10^8 CFU/g of LA)/kg diet, LA3 (T3): 3 (× 10^8 CFU/g of LA)/kg diet, IM1 (T4): 1 g of IM/kg diet, and IM2 (T5): 2 g of IM/ kg diet. After 60 days, the function of growth and intestinal protease and amylase showed a significant increase in IM treatments. Serum levels of total protein and superoxide dismutase in LA3 treatment, as well as albumin, catalase, and glutathione peroxidase in LA3 and IM2 treatments were significantly increased. Serum level of malondialdehyde in LA and IM treatments, as well as alkaline phosphatase (ALP) in LA treatments, alanine aminotransferase in LA and IM2 treatments, and lactate dehydrogenase in LA3 treatment was significantly decreased. Serum levels of all the immune parameters in LA3 treatment, as well as alternative complement pathway hemolytic and nitroblue tetrazolium in IM2 treatment were significantly improved. Mucosal level of protease in LA3 and IM2 treatments, total immunoglobulin, and lysozyme in LA and IM2 treatments, as well as ALP and peroxidase in LA3 treatment was significantly increased. Cumulative mortality rate in LA and IM treatments was significantly decreased compared to control after the 14-day challenge with A. hydrophila. It is recommended to include IM2 in the diet of C. carpio juveniles with regard to its beneficial effects on growth and immunity status.