文摘
The effects of probiotic Bacillus TC22 (isolated from intestine of infected sea cucumber) and prebiotic fructooligosaccharide (FOS) on growth, immunity and disease resistance in sea cucumber Apostichopus japonicus were studied. Six experimental diets were formulated with combinations of three levels of TC22 (0, 107 and 109 CFU g? diet) and two levels of FOS (0 and 0.5%) in a 3 × 2 factorial experiment. At the end of the 8-week feeding trial, animals were challenged by injecting Vibrio splendidus. The results revealed that the specific growth rates (SGR) of sea cucumbers were not affected by TC22 and FOS, or the interaction between TC22 and FOS (P > 0.05). However, there were significant interactions between TC22 and FOS for immune response and disease resistance in sea cucumbers (P < 0.05). When sea cucumbers were fed with TC22 at 109 CFU g? feed and 0.5% FOS alone or in combination, the phagocytosis, respiratory burst and phenoloxidase activity of sea cucumber coelomocytes were significantly enhanced; the disease resistance against V. splendidus infection was also increased significantly (P < 0.05). However, dietary combination of TC22 at 109 CFU g? diet and 0.5% FOS did not yield significantly higher efficiency than either TC22 at 109 CFU g? diet or 0.5% FOS used alone (P > 0.05). Therefore, further studies should examine the effects of combinations of other levels of FOS (> 0.5% or < 0.5%) and TC22 on the immunity and disease resistance of sea cucumbers.