Presentation and evaluation of formulated feed for mud crab Scylla serrata

Abstract

A formulated pellet and ball form feed with 41.6% crude protein, consisting of fish meal, squid meal, shrimp meal, mantis shrimp meal, soyabean meal, bread flour and other additives was evaluated for mud crab, Scylla serrata. Fish meat (tilapia), which is conventionally used for feeding mud crab by farmers was used as control. Crabs with average weight of 151.7 g were stocked in 500 l oval shaped FRP tanks containing seawater @ 2 crabs per tank with six replicates per treatment. The crabs were fed daily with dry pellets @ 10% of their body weight in a 30-day feeding trial. The crabs showed excellent acceptability of the compounded feed from the start and had shown a weight gain of 36.7% and a feed gain ratio (FGR) of 2.94, compared to 33.5% weight gain and 5.56 FGR shown by the crabs fed with fish meat. The amino acid profiles of the feed, fish meat and the crabs before and after the feeding trial showed that the ratio of indispensable amino acids (IAA) and the dispensable amino acids (DAA) is same (0.8) for both feeds. Performance of dry as well as semimoist form of pelleted feeds also studied. In a 30-day feeding trial, the weight gain of crabs fed dry feeds was significantly higher (p<0.05) compared to moist feeds. It was due to the higher wastage of feed (30.4%) in semi-moist feeds compared to the dry feeds (17.2%). There was no difference in the FGR shown by different feeds. The proximate composition of crabs fed with the different forms of feed also did not show any variation. Dry pellet feed is preferred over the semi-moist form of feed for feeding mud crab.