Isolation and characterization of lactic acid bacteria from the fish intestine for application as probiotics in young common carp Cyprinus carpio L. diet

The current study was conducted to investigate the possibility of using Lactic acid bacteria LAB isolated from the intestines of common carp, Cyprinus carpio, as dietary probiotics to enhance the nutrition and growth of common carp juveniles. The bacteria were cultured on MRS agar and their cultural and biochemical characteristics were confirmed. The isolated probiotic bacteria were used as dietary supplements at concentrations of 10^6, 10^7, and 10^8 and their effect on the nutrition and growth of common carp fingerlings was evaluated. The results showed clear positive effects of adding the probiotic Lactobacilli in fish feed, with a relative growth increase from 105.26 to 178.14% with increasing probiotic concentration compared to the control. The feed conversion ratio also improved from 2.94 to 1.83 with increasing levels of probiotics compared to the control. In addition, all other indicators improved, including weight gain, specific growth rate, protein efficiency ratio, digestibility, and beneficial intestinal flora, with increasing probiotic concentration in the feed compared to the control, with a significant difference. It was concluded that LAB isolated from the intestines of common carp.can be effectively used as probiotics in common carp C. carpio fingerlings feed, with positive results.