Effects of dietary probiotic yeast on growth parameters in juvenile sea cucumber, Apostichopus japonicus

H26 or C14) groups (P < .05); the body wall crude protein and carbohydrate/ash contents in sea cucumbers fed the HC diet were significantly higher/lower than those in the BD and/or single probiotic yeast (H26 or C14) groups (P < .05). After 8 weeks of feeding, a significantly higher content of arachidonic acid (20:4n-6), and lower contents of oleic acid (18:1) and eicosadienoic acid (20:2n-6) plus eicosatrienoic acid (20:3n-9) were detected in the body wall of sea cucumbers fed the HC diet compared to those fed the BD diet (P < .05). Feeding the mixture for 4 and/or 8 weeks significantly improved phagocytic activity and respiratory burst in coelomocytes (P < .05). In addition, there was an observed enhancement in lysozyme activity and phenoloxidase activity in coelomic fluid supernatant and in coelomocyte lysate supernatant compared with the BD and single probiotic yeast (H26 and/or C14) groups (P < .05). After feeding for 4 and/or 8 weeks, sea cucumbers fed the HC diet showed a significant increase in the numbers of total bacteria, and a decrease in the numbers of vibrio bacteria in the intestine compared with the BD group (P < .05). After 8 weeks of feeding, gel electrophoresis revealed that the mixture of H26 and C14 did not significantly affect the composition of intestinal microbiota. These data suggest that a mixture of H26 and C14 supplementation can improve the growth, enhance digestive enzyme activity, add nutritional value and stimulate the innate immune system of sea cucumber juveniles.