Abstract:To investigate the effects of different brands of commercial diets on the weight gain rate, specific growth rate, feed conversion ratio, feeding rate, and apparent protein digestibility of the juvenile sea cucumber, the juvenile sea cucumber (Apostichopus japonicus) (initial wet weight 5.0-6.7 g) were fed with the diets containing various particle diameters of Asterias echino-skin powder (two commercial feeds as control) for 60 days. The results showed that the survival rate of A. japonicus is not impacted by diets (P>0.05). The trend of the average weight gain rate was same with the specific growth rate of sea cucumber, which was higher in commercial feed 2 group and lower in commercial feed 1 group. The feed conversion ratios (FCR) of sea cucumber fed with Asterias echino-skin was the lowest (0.993) but no significant difference with the other two groups (P<0.05). The feeding rate (FR) of sea cucumber was similar between Asterias echino-skin group and commercial feed 1 group (P>0.05), but it was significantly lower than that of the commercial feed 2 group (P<0.05). The feed efficiency of sea cucumber fed with Asterias echino-skin group was significantly higher than those of other two groups that have no significant difference (P>0.05). The highest apparent protein digestibility of sea cucumber was in Asterias echino-skin group (67.28%), which was significantly higher compared with commercial feed 1 group but without significant difference compared with the commercial feed 2 group (P>0.05). These findings indicate that supplementation of Asterias echino-skin in diets could improve the growth performance and feed utilization of A. japonicus, and the Asterias echino-skin powder can be used as a feed additive.