Incidence of loose shell syndrome disease of the shrimp Penaeus monodon and its impact in the grow-out culture.

摘要

This article reports the changes in growth, production and histology of Penaeus monodon infected with loose shell syndrome in a modified extensive grow-out ponds. The carapace of the affected shrimp was papery and the gill was brown in colour. There was fouling of the gill filaments caused by protozoa and muddy particles. Hepatopancreas tissue had no fat globules in its cells. There was a secondary infection of the shrimp which was caused by microbes and led to the severity of the disease. In the loose shell-affected pond, the final average body weight of shrimps at 147 days of culture was 27.87 g which was lower when compared with the shrimps in the normal pond (31.29 g at 140 days). The average daily growth rate of the loose shell-affected shrimp was 0.18 g, while 0.22 g in the normal pond. The mean final survival rate of the loose shell-affected and normal ponds were 60.65 and 81.95%, respectively. The mean biomass production of the affected pond was 1058.97 kg/ha, while 1915.21 kg/ha in the normal pond. The poor survival and biomass production in the loose shell-affected pond was due to the cannibalistic behaviour of the shrimp during the course of the disease. The water quality in the loose shell-affected pond was more or less similar to the natural pond.