Effects of different seaweed diets on growth of juvenile sea cucumber Apostichopus japonicus
YIN Xu-wang1, LI Wen-xiang1, BAI Hai-feng1,2, LIU Gang1, ZHOU Wei1
1.Key Laboratory of Hydrobiology in Liaoning Province, Dalian Ocean University, Dalian 116023, China; 2. Fisheries Research Institute of Shanxi, Xi’an 710086,China
Abstract: Juvenile sea cucumber Apostichopus japonicas with body weight of (1.25±0.02)g was reared in a 25 L plastic tank at a rate of 6 individuals each tank and fed 8 diets containing various proportions of fresh seaweeds (sea lettuce Ulva pertusa, chondrus Chondrus ocellatus, sea mustard Undaria pinnatifida) and powder and 25% sea mud for 60 days to evaluate the effects of different seaweed diets on the growth of sea cucumber juveniles at water temperature of (18±1)℃. Ammonia nitrogen level in water and growth were measured at the end of the feeding trial. The results showed that there were no significantly differences in survival rates (over 80%) of sea cucumber fed different diets (P>0.05). However, there were significant higher specific growth rate [(1.38±0.13)%/d] and food conversion efficiency in the sea cucumber juveniles fed fresh sea lettuce than those in the other diet groups (P<0.05), without significantly differences in food conversion efficiency among the other diet groups (P>0.05). There was the maximal food ingestion rate and fecal production rate in the sea cucumber fed fresh sea lettuce, significantly different from those in the sea cucumber fed other diets (P<0.05 ). At the end of the experiment, there was the minimal ammonia nitrogen concentration [(0.005±0.003)mg/L] in the water where the sea cucumber juveniles fed fresh sea lettuce were reared, and there was the maxima ammonia nitrogen concentration [(0.021±0.016)mg/L] in the water where the sea cucumber juveniles fed sea lettuce powder were reared, with significant difference between them (P<0.05). The findings indicate that the sea cucumber juveniles have good growth, and the ammonia nitrogen concentration in the water is kept low when they are fed fresh sea lettuce.
2015, Vol. 30 
