LAUSR

Vibrio parahaemolyticus is often related to infections and high mortality rates in shrimp farming. The use of probiotics is an alternative to the use of antibiotics in farming systems. Among the benefits, probiotics can boost the immune status of shrimp, making them more resistant to diseases. An experimental rearing was conducted for 60 days to determine the effects of Bacillus subtilis and Bacillus circulans on the growth and disease resistance in Litopenaeus vannamei juveniles. Shrimp groups were designated according to the feed offered: commercial feed + B. subtilis (BS); commercial feed + B. circulans (BC); and feed without bacteria (control). The expressions of proPO, LGBP, and HEM genes were quantified by qPCR after 60 days of rearing and after 24 h of V. parahaemolyticus challenge. The growth and expression of immune genes were significantly higher in shrimp fed with BS and BC diets. Furthermore, animals fed with BC diet had a greater survival after the injection of V. parahaemolyticus. Bacillus spp. significantly increased in shrimp guts fed with BC and BS diets. Supplementation of L. vannamei diet with B. subtilis and B. circulans contributed to an increase in shrimp weight gain and enhancement of shrimp immune status.