Effect of dietary supplementation of brewers yeast and nucleotide singularly on growth, survival and vibriosis resistance on juveniles of the gastropod spotted babylon (Babylonia areolata)

摘要

This study was undertaken to evaluate the use of brewers yeast and nucleotides as a growth promoter and to provide vibriosis resistance for the juveniles of gastropod spotted babylon (Babylonia areolata). Juvenile spotted babylon (0.3 g initial weight) were randomly distributed at a density of 50 snails in 45-L aquaria and fed a basic diet (40% crude protein) containing two incremental levels of 1 and 2% brewers yeast and nucleotides singularly for 4 months. After the feeding trial, snails from each treatment were challenged by pathogenic bacteria Vibrio alginolyticus given by intramuscular injection and kept under observation for 5 days to record clinical signs and daily mortality rates. Results indicated that the snails fed with diets supplemented with brewers yeast or nucleotides exhibited significantly greater growth than those fed the basic diet (P < 0.05) and significantly better food conversion ratios compared to snails fed the basic diet (P < 0.05). These results indicated that dietary supplementation of brewers yeast or nucleotides, at least at the tested dosages, enhanced spotted babylon growth. Supplementing the diet with 1% brewers yeast promises to provide appropriate resistance to V. alginolyticus.