Dietary Addition Of Rhodotorula Mucilaginosa On The Growth Performance, Immune And Digestion Ability Of Juvenile Sea Cucumber A. Japonicus

Over use of antibiotics and various chemicals caused significantly negative impacts, and these effects threatened the green-development of aquaculture greatly. In recent years, probiotics, due to its environmental protection, no pollution, no resistance, no residue and wide ranges of characteristics, had received widespread attentions both here and abroad, and had become a better alternative to antibiotics.In this paper, Rhodotorula mucilaginosa, as one of probiotics, stored in our lab, was selected to prepare the probiotics using liquid fermentation method. Then the content of astaxanthin, β-carotene and vitamin E of Rhodotorula mucilaginosa was tested. This article studied the effects of dietary addition of Rhodotorula mucilaginosa on the growth performance, immune activities and digestive enzyme activities of Apostichopus japonicus. There were four treatment groups in this experiment. Dietary addition of Rhodotorula mucilaginosa of each treatment group was 0, 106, 107 and 108 CFU·g-1 respectively. By determination, the results showed that the contents of astaxanthin, β-carotene and vitamin E for Rhodotorula mucilaginosa were 23.34, 79.16 and 166.43 μg/g, respectively. It was shown that dietary addition of Rhodotorula mucilaginosa at the evel of 107 CFU/g significantly increased weight and the specific growth rate of sea cucumbers A. japonicas(p<0.05). For the intestinal digestive enzyme activity, it was shown that amylase activity, alginic acid and lipase enzyme activity were significantly improved for the sea cucumber fed with Rhodotorula mucilaginosa at 107 CFU/g diet(p<0.05); The highest values of the cellulose enzyme activity were found in sea cucumber fed with Rhodotorula mucilaginosa at 106 CFU/g diet(p<0.05); However, Rhodotorula mucilaginosa had not significant effect on the proteinase activities. It was shown that TCC activity, LSZ, SOD and CAT activity were significantly improved for the sea cucumber fed with Rhodotorula mucilaginosa at 106 CFU/g diet(p<0.05); The highest values of phagocyte phagocytosis rate, T-NOS activity, PO activity, ACP and AKP activity were found in sea cucumber fed with Rhodotorula mucilaginosa at 107 CFU/g diet(p<0.05). The cumulative mortality of sea cucumber fed with Rhodotorula mucilaginosa after V. Splendidus challenge was lower than that of control group. In addition, body wall oxidation resistance test of sea cucumbers A. japonicus indicated that TBARS values and the protein carbonyl levels of the sea cucumbers of the treatment groups were significantly reduced for the sea cucumber fed with Rhodotorula mucilaginosa at 106 CFU/g diet(p<0.05).The study tested that dietary addition of Rhodotorula mucilaginosa could increase the growth performance, immune activity, digestive enzyme activity, disease resistance and antioxidant capacity. In conclusion, 106 and 107 CFU/g feed is more appropriate supplementation.