Effect of molasses supplementation on growth performance, water quality and microbial dynamics during indoor rearing of pacific white shrimp Penaeus vannamei Boone, 1931

Abstract

A study was conducted with Pacific white-leg shrimp (Penaeus vannamei Boone, 1931) juveniles to ascertain the effect ofmolasses supplementation on the growth performance, culture environment and microbial dynamics of rearing water. Theweight gain at the end of the experiment of 55 days duration were significantly (p<0.05) higher in molasses supplementedgroup (12.08±0.45 g) as compared to control (10.44±0.34 g). Apparent feed conversion ratio (AFCR) was found significantly(p>0.05) lower in case of molasses supplemented group with higher survival percentage. Supplementation of molasses alsoimproved the rearing water quality. The total ammonia nitrogen (TAN) level was significantly (p<0.05) lower in the rearingwater of molasses supplemented tank (2.213±0.165 ppm) compared to control (2.915±0.191 ppm). There was no significantdifference in total heterotrophic bacteria (THB) and total Vibrio (TV) load between the water of the two groups. However,the proportion of TV to THB was significantly lower in case of molasses supplemented group as compared to control. Thisstudy indicated that supplementation of molasses can significantly improve the growth performance of P. vannamei withbetter feed utilisation and also improves the water quality by reducing the level of toxic gas i.e. ammonia in water. Keywords: Ammonia, C:N ratio, Molasses, Vibrio