Department of Aquaculture Technology

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Browsing Department of Aquaculture Technology by Subject "Antioxidant capacity"

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    Dietary mannan oligosaccharide (MOS) improves growth performance, antioxidant capacity, non-specific immunity and intestinal histology of juvenile Chinese mitten crabs (Eriocheir sinensis). Aquaculture, 510: 337–346.
    (Elsevier, 2019-08-15) Jian-Ting Lu; Changle Qi; Samwel Mchele Limbu; Fenglu Han; Jian Qin; Liqiao Chen; Lu Yang; Xiaodan Wang
    Mannan oligosaccharide (MOS) is a common prebiotics to improve health and immunity of animals in aquaculture. However, its optimum level and effects on the immune response in crab are currently unknown. The present study investigated the optimum level of dietary MOS supplementation and its effects on growth performance, antioxidant capacity, non-specific immunity and intestinal morphology of juvenile Chinese mitten crab (Eriocheir sinensis). Crab juveniles (2.95 ± 0.05 g) were fed either a control diet or one of the six diets supplemented with MOS (0.1%, 0.2%, 0.3%, 0.4%, 0.5% and 0.6%) for eight weeks. The crabs fed 0.3% MOS showed greater weight gain, specific growth rate and lower feed conversion ratio than those fed the control diet. The acid phosphatase activity was significantly higher in the gut of crab fed 0.2% MOS than those fed the other diets except the 0.3% MOS diet. The lysozyme and alkaline phosphatase activities in the gut were higher in crabs fed the 0.1% and 0.3% MOS diets compared to those fed other diets. The antioxidant capacity was higher in crab fed the 0.2% and 0.3% MOS diets than those fed other diets. In addition, the mRNA expression of genes related to immunity (E. sinensis (Es)-Crustin, Es-Toll2, Es-Lech and Es-prophenoloxidase (proPO)) in the hepatopancreas of crabs fed the 0.2 and 0.3% MOS diets were significantly up-regulated compared with those fed other diets. Duplicature length and width increased significantly in the crab fed 0.3% MOS than other diets. The optimum inclusion levels of MOS were 0.32%, 0.20% to 0.30% and 0.27% to 0.29% based on growth performance, antioxidant capacity and immunity, respectively. This study indicates that supplementing diets with MOS at 0.2% to 0.3% can improve growth performance and enhance antioxidant capacity and immunity in E. sinensis.
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    Modulation of growth, antioxidant status, hepatopancreas morphology, and carbohydrate metabolism mediated by alpha-lipoic acid in juvenile freshwater prawns Macrobrachium nipponense under two dietary carbohydrate levels.
    (Elsevier, 2022-01-15) Ding Z; Xiong Y; Zheng J; Zhou D; Kong Y; Qi C; Liu Y; Ye J; Samwel Mchele Limbu
    Carbohydrate is commonly used in aquatic organism as the cheapest energy source. However, most aquatic animals are low efficient in utilizing dietary carbohydrate for energy provision. Therefore, improving the utilization efficiency of high carbohydrate by aquatic organisms is important for sustainable aquaculture development. Alpha-lipoic acid (α-LA) is a cofactor of key enzymes involved in glucose metabolism. However, its role in regulation of carbohydrate metabolism in aquatic animals is currently unknown. This study investigated the effects of α-LA on growth, antioxidant status, hepatopancreas morphology, and carbohydrate metabolism of freshwater prawns Macrobrachium nipponense under two dietary carbohydrate levels. Six diets were formulated using casein and fish meal as the protein sources, fish oil and soybean oil as the lipid sources, and corn starch as the carbohydrate source, at two carbohydrate levels (15% and 30%) and three concentrations of α-LA supplementation (0, 700, and 1400 mg/kg). Each experimental diet was fed to juvenile prawns (mean weight 0.050 ± 0.003 g), twice daily to apparent satiation, in five replicates. In the 15% (low)-carbohydrate groups, weight gain was significantly reduced in prawns fed 1400 mg/kg α-LA compared with 0 or 700 mg/kg α-LA, but there was no significant effect in the 30% (high)-carbohydrate groups. Survival was significantly higher among prawns fed 700 mg/kg α-LA compared with 0 or 1400 mg/kg α-LA regardless of the carbohydrate level. The levels of dietary carbohydrate and α-LA also significantly affected the activities of key enzymes involved in glycolysis and the citric acid cycle. The activities of hexokinase and pyruvate kinase activities were highest in prawns fed l400 mg/kg α-LA, in both the low- and high-carbohydrate groups. Supplementation with 700 or 1400 mg/kg α-LA significantly increased the activities of 6-phosphofructokinase, pyruvate dehydrogenase, and succinate dehydrogenase regardless of the carbohydrate level. The level of malondialdehyde decreased significantly with increased α-LA supplementation; in contrast, the levels of superoxide dismutase, glutathione peroxidase, and glutathione were significantly higher in prawns fed 700 or 1400 mg/kg α-LA when compare with those fed no α-LA supplement. Dietary α-LA did not affect the overall morphology of the hepatopancreas, but 1400 mg/kg α-LA reduced the number of B (blister-like) cells. Thus, 700 mg/kg α-LA supplementation under either dietary carbohydrate level could improve the antioxidant status, carbohydrate metabolism, and morphology of the hepatopancreas in juveniles of M. nipponense. We conclude that α-LA supplementation can be used to improve the efficiency of carbohydrate utilization when a 30% carbohydrate diet is used for this prawn.