Isolating and characterizing bacteria in the intestine of wild sandfish, Holothuria scabra as probiotics candidate

Abstract

The research aims to isolate bacteria as potential probiotics for rearing of sandfish, H. scabra. The procedures were isolating bacteria from nature sandfish's intestines, characterizing, identifying, enzymatic hydrolysis activity and pathogenic testing, and in vivo testing of candidate probiotics. Identification of probiotic bacteria was based on 16S rRNA encoding gene sequence. Similarity identification was conducted by using BLAST on NCBI. The enzymatic activity test was carried out through Extra Cellular Product (ECP) of isolated bacteria. The in vivo test was done in twelve 1.2 m3 tanks. Initial mean body weight of juvenile was 6.0 ± 4.3 g and total length 4.3 ± 0.6 cm. The results, there were three isolated bacteria as candidates of probiotics with code M-4, Q-1, and E-2 which had high ability in hydrolyzing gelatin, casein, amylase, lecithin, and lipase enzymes. The M-4 was identified as Gamma proteobacterium with a 99% similarity, Q-1 and E-2 were identified as Bacillus subtilis and Bacillus sp with 98% and 97% similarity. The in vivo trial of probiotic candidate in feed for juvenile gave higher survival rate 95% compare to control 91%. The growth performance was (7.3 ± 2.1 g; 4.5 ± 0.7 cm) in probiotic which higher compare to control (6.0 ± 1.8g; 4.3 ± 0.8 cm).