Enhanced growth of black tiger shrimp penaeus monodon by dietary supplementation with Bacillus (BP11) as a probiotic

Abstract

Bacillus isolate P11 (BP11), isolated from the gastrointestinal tract of the black tiger shrimp, Penaeus monodon, was evaluated for its potential use as a probiotic feed supplement for P. monodon culture. BP11, a Gram-positive spore forming bacteria, was identifed as a member of the genus Bacillus and most likely to be an isolate of Bacillus subtilis, based on biochemical tests, physical morphology, and 16S rRNA gene fragment sequence analysis. BP11 is likely to be safe as a probiotic for P. monodon since no detectable level of antimicrobial substance or Bacillus diarrheal enterotoxin production was found. When the regular feed of P. monodon was supplemented with BP11 at ~109 CFU g-1 feed a higher shrimp growth, feed conversion ratio, survival and general health was obtained for both postlarvae (PL) shrimp in concrete tanks and in an earthen pond. In addition, and importantly, the oral administration of BP11 in the shrimp feed led to adherence to the shrimps' intestine surface with BP11 bacteria and an increased immunity to Vibrio harveyi 639 infection, including a reduced mortality. BP11 in dried feed had a reasonable shelf life, with viable cell counts of ~108 and 109 CFU g-1 remaining after 6-months storage at room temperature and 4°C, respectively. © 2011 Utiswannakul P, et al.