Effect of orally administered vibrio bacterin on immunity, survival and growth in tiger shrimp (Penaeus monodon) grow‐out culture ponds

Vibriosis is one of the important diseases causing economic loss to the shrimp industry worldwide. The present study reports field observations on the immune stimulatory effect of vibrio bacterin in commercial tiger shrimp (Penaeus monodon) grow‐out culture ponds (n = 62) which were grouped under three stocking densities; low (6–8 nos per m2), medium (9–11 nos per m2) and high (12–14 nos per m2). The bacterin was administered in feed as a top dressing at final concentration equivalent to 2 × 108 CFU per kilogram feed twice a week throughout the culture period. In 20 representative ponds, total haemocyte count and prophenoloxidase activity in shrimp were significantly (P