| Summary: | 碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 103 === The study evaluated the effects of different concentrations of mannitol and vitamin C on rearing performance, antioxidant capacity and hypoxia resistance of white shrimp (Litopenaeus vannamei).This study was conducted in two phases; Phase I assessed the dietary effect of mannitol and vitamin C on shrimp’s rearing performance while Phase II examined the post effects on survival, immune response, antioxidant capacity and physiological response of those shrimp when subjected to hypoxia.
In Phase I, shrimp (1.29±0.01 g) were fed diet supplemented with mannitol extract at 1 g/kg (M1), 2 g/kg (M2), 4 g/kg (M4), 8 g/kg (M8) and 2 g/kg L-Ascorbic acid 2-phosphate sesquimagnesium salt hydrate (C2) for 12 weeks in triplicates. Basal diet without mannitol and vitamin C supplement served as the control (C). The average crude protein and crude lipid of diets were 34.96% and 12.72%, respectively. The treatments had no effect on survival. Shrimp fed diet containing M2, M4 and C2 had the highest weight gain (WG) at 295%, 282% and 280%, respectively, among which no differences were found. C-shrimp had the lowest WG, 209%
In Phase II, under non-stress condition, M2-, M4- and M8-shrimp had lower serum glucose level while M1- and M8-shrimp had higher triglycerides levels than shrimp of other treatments. Shrimp fed mannitol and vitamin C had higher total haemocyte count than the control. M1- and M2-shrimp had higher superoxide dismutase (SOD) and all white shrimp fed diet with mannitol had higher glutathione peroxidase (GPx) and glutathione reductase (GR) than the control. Finally, C2-shrimp had the highest total antioxidant status (TAS). When under stress, control shrimp had the highest oxygen consumption rate and lowest total haematocyte count. Furthermore, lactate, alanine transaminase and aspartate transaminase increased in all treatments. M2-, M4-, M8- and C2-shrimp had higher SOD than the control. Moreover, M8 had higher GPx and M4, M8 and C2 had higher GR than the control. Finally, shrimp fed mannitol diet had higher TAS than the control.
In conclusion, dietary mannitol supplement at 2 and 4 g/kg improved growth performance and increase hypoxia resistance in white shrimp, which was comparable to L-Ascorbic acid 2-phosphate sesquimagnesium salt hydrate supplement at 2 g/kg vitamin C for white shrimp culture. When under hypoxia stress, M8-shrimp had higher antioxidant capacity than C2-shrimp.
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