Hongming Ma

Interaction of dietary Bacillus subtilis and fructooligosaccharide on the growth performance, non-specific immunity of sea cucumber, Apostichopus japonicus.

A feeding experiment was conducted to investigate the interaction of probiotic Bacillus subtilis and prebiotic fructooligosaccharide (FOS) on the growth performance, immunity, intestinal microflora and disease resistance of sea cucumber (Apostichopus japonicus). Five hundred and forty individuals (initial body weight: 5.06 +/- 0.10 g, mean +/- S.E) were fed nine practical diets according to a 3 x 3 factorial design: the basal diet as the control diet supplemented with three levels of B. subtilis (0, 1.82 x 10(7) or 4.95 x 10(7) CFU g(-1) diet), crossed with 0, 0.25% or 0.50% FOS. After 8 weeks, three sea cucumbers per tank were sampled for bacterial quantification and immunity determination. Then all the sea cucumbers left were challenged by Vibrio splendidus. The results showed that dietary B. subtilis significantly increased the specific growth rate (SGR), total coelomocytes counts (TCC), phagocytosis of sea cucumbers, the counts of total viable bacteria and disease resistance to V. splendidus (P < 0.05), whereas the counts of Vibrio decreased. However, dietary B. subtilis had no significant effect on phenoloxidase (PO) activity in coelomocyte lysate supernatant (CLS) (P > 0.05). The SGR, PO activity, total viable bacterial counts (TBC) and Vibrio counts (VBC) were significantly affected by dietary FOS. In the group with 0.50% FOS, TCC, phagocytosis and PO activity significantly increased compared to the group fed without FOS in diet (P < 0.05). In the groups with 1.82 x 10(7) CFU B. subtilis/g diet, FOS supplementation remarkably decreased VBC. And higher level of FOS (0.50%) resulted in significantly higher TCC and PO activity compared with 0.25% FOS (P < 0.05). Moreover, the animals fed with diets supplemented with 0.25% and 0.50% FOS at each B. subtilis level had notably lower cumulative mortality after 14 days following V. splendidus exposure (P < 0.05). Under the experimental conditions, dietary B. subtilis and FOS had a synergistic effect on enhancing immunity and disease resistance of sea cucumber (P < 0.05).

EFFECTS OF VITAMIN E ON ANTIOXIDANT ENZYME ACTIVITIES AND FATTY ACID COMPOSITIONS IN JUVENILE ABALONE HALIOTIS DISCUS HANNAI INO

Abstract A 240-day feeding trial was conducted in a recirculated water system to investigate the effects of dietary vitamin E on the activities of antioxidant enzymes (catalase, CAT; superoxide dismutase, SOD; glutathione peroxidase, GPX) and the composition of fatty acids in abalone, Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 0.71 ± 0.00 g; initial shell length: 15.49 ± 0.04 mm) were fed to satiation one of three semipurified diets containing 0, 50, and 5,000-mg/kg vitamin E, respectively. Abalone were sampled on the 120th day and the 240th day, respectively. There were no significant differences in activities of CAT and SOD in soft body of abalone fed with different levels of dietary vitamin E for 120 days (P > 0.05), but significantly higher activity of GPX was found with 5,000-mg/kg dietary vitamin E (P < 0.05). Activities of CAT and GPX were significantly elevated by dietary vitamin E on the 240th day. The lowest value of 18:1n-9, 18:2n-6 and the highest value of 22:6n-3 in soft body were found with 50 mg/kg dietary vitamin E supplement on the 120th day. On the 240th day, the content of monounsaturated fatty acids (MUFA) in abalone with 50-mg/kg dietary vitamin E supplement was significantly higher than those in the other two treatments (P < 0.05). There were no significant effects of dietary vitamin E on the content of polyunsaturated fatty acids (PUFA) in abalone during the two sampling periods (P > 0.05). In conclusion, 50-mg/kg dietary vitamin E supplement elevated the activities of antioxidant enzymes and could protect MUFA from peroxidation damage. Excessive dietary vitamin E (5,000 mg/kg) did not serve as an antioxidant any more, but tended to be a pro-oxidant in the soft body of abalone.

INTERACTION BETWEEN VITAMINS A AND D ON GROWTH AND METABOLIC RESPONSES OF ABALONE HALIOTIS DISCUS HANNAI, INO

Abstract A 152-day growth experiment was conducted in a recirculated water system to investigate the interaction between vitamins A (retinol) and D (cholecalciferol) on growth and metabolic responses in abalone Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 0.35 ± 0.03 g; initial shell length: 11.31 ± 0.25 mm) were fed to satiation one of 16 semipurified diets containing 0, 1 × 103, 1 × 105, 1 × 106 IU/kg vitamin A and 0, 500, 1 × 103, 5 × 103 IU/kg vitamin D in a 4 ×4 factorial design. Abalone were weighed and shell-length measured on the 76th day and the 152nd day, respectively. The total specific growth rate (SGR) during the 152 days, neither the SGR in the first 76 days nor in the second 76 days, was significantly influenced by the interaction between vitamins A and D. Dietary vitamins A and D significantly stimulated viscera 25-hydroxyvitamin D3 [25(OH)D3] and 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] contents in a cooperative fashion. Dietary vitamin A generally increased the alkaline phosphatase (AKP) activity in viscera except the excessive supplement (1 × 106 IU/kg), which significantly decreased AKP activity. Dietary vitamin D significantly increased AKP activity. Contents of P, not Ca and Mg, in soft body increased with dietary vitamin D supplement. Dietary vitamin A significantly improved contents of lipid and retinol in soft body and viscera, respectively. Meanwhile, dietary vitamin D significantly increased contents of ash and cholecalciferol in soft body and viscera, respectively. Based on these results, interaction between vitamins A and D was expressed in various manners as different indicators were considered, though there was potential antagonism mechanism at molecular level between the two fat-soluble vitamins.