Immunity enhancement in black tiger shrimp (Penaeus monodon) by a probiontbacterium (Bacillus S11)

Survival and growth of Penaeus monodon fed the probiont Bacillus S11 in two 90-day culture trials were increased compared with non-treated shrimp. Bac illus S11 also efficiently activated and increased the engulfment of foreig n particles (phagocytic activity) as measured by % phagocytosis and phagocy tic index (PI) in hemolymph. Phenoloxidase and antibacterial activities inc reased with age in all shrimp, but were even further increased by probiotic treatment. Following the second trial, after 90 days' culture with and wit hout Bacillus S11 feed additives, shrimp were exposed to pathogenic, lumine scent bacteria (Vibrio harveyi). After 10 days' exposure to V. harveyi, pro biotic-treated shrimp had significantly greater (p < 0.05) survival (54.3%) compared with non-treated shrimp (35.5%). Immune responses were substantia l in both treatment groups following the 10-day challenge, but were more pr onounced with the probiotic-treated shrimp. The PI was significantly greate r with probiotic-treated shrimp (2.7 +/- 0.8) compared with controls (0.6 /- 0.3). Bacillus S11 provided; disease protection by activating both cellu lar and humoral immune defenses, as well as presumably providing competitiv e exclusion in the shrimp's gut. (C) 2000 Elsevier Science B.V. All rights reserved.