Characteristics of Bacillus CgM22 and the Effect of Induction on the Growth Rate in Carp (Cyprinus carpio)

Abstract

Bacillus is a potential probiotic candidate which is currently widely applied in aquaculture. Bacillus can be found in various hosts, one of which is found in the intestines of fish. This study contains the genus Bacillus subtilis intestinal fish Bacillus CgM22. The steps taken were the characterization of Bacillus CgM22 with gram staining test, inhibition test, and proteolytic test. The method at the fish rearing stage is an experimental method with a Completely Randomized Design (CRD) model that uses four treatments and three replications. Treatment A was control with no addition of antimicrobials in the feed. Treatment B was the addition of 108 CFU Bacillus CgM22 at a dose of 15 ml/kg of feed. Treatment C was the addition of supernatant from Bacillus CgM22 at a dose of 5 ml/kg of feed. Treatment D was the addition of supernatant from Bacillus CgM22 at a dose of 10 ml/kg of feed. Furthermore, Bacillus CgM22 was induced in carp (Cyprinus carpio) to see its effect on absolute weight. The results showed that the gene characteristics of the bacteria genus Bacillus CgM22, including gram-positive bacteria, had the shape of a rod or Bacillus. It was also found that the growing Bacillus CgM22 could inhibit the growth of Aeromonas hydrophilla. There are proteolytic test results that can be seen from the formation of a clear zone with a proteolytic index of IP = 2.19. Based on statistical tests, it was shown that the addition of probiotics was not significantly different (P > 0.05) on the growth rate of carp (Cyprinus carpio).