Growth, survival and feed conversion of juvenile shrimp (Penaeus monodon) fed a betaine/amino acid additive

Abstract

Diets low in animal but high in plant protein were enhanced with a chemoattractant FinnStim (FS), a betaine/amino additive. These were fed to juvenile shrimp, Penaeus monodon, in three tank experiments. All diets were formulated to be isonitrogenous (35% protein) and isocaloric. In run 1, where soybean meal was used as the plant protein source (33%), graded levels of FS (0 to 2.0%) were added to the basic mix (B). Shrimp fed the diet with 1% FS had a significantly ( alpha =0.05) higher weight gain than the other treatments and a feed conversion ratio (FCR) which was higher than B and B+2% FS but not significantly different from the other FS levels. However, survival, specific growth rate (SGR) and feed intake were similar. In run 2 diet palatability, which may be affected by plant protein, was considered. Diets with a lower soybean meal content (18%) and 16% papaya leaf meal, with and without 1% FS, were tested. A higher weight gain and SGR were obtained for shrimp fed FS but survival, feed intake and FCR were not significantly different from those without FS. In run 3, where leaf meal was increased to 25%, shrimp fed 1% FS yielded a significantly better weight gain, SGR, feed intake and FCR, but survival rates were not significantly different. FS did not increase feed intake but may have caused faster feed consumption, resulting in less feed disintegration and nutrient loss. It could also have acted as a stimulant and counteracted the palatability problem of the 25% leaf meal diet. However, much of the response was evidently caused by the physiological role of betaine as methyl donor and osmoprotectant.