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摘要
This study aimed to investigate the interactive effects of dietary carbohydrate levels and lipid sources on growth performance, tissue fatty acid (FA) profiles and intermediary metabolism of Megalobrama amblycephala. Fish (average weight: 37.98 +/- 0.07 g) were randomly fed one of eight diets containing two carbohydrate levels (30% and 43%) and four lipid sources (fish oil, FO; soybean oil, SO; palm oil, PaO; and mixed oil (FO: SO: PaO = 1: 1: 1), MO) for 11 weeks. Little difference (P > 0.05) was observed in growth performance and wholebody composition (except for lipid). However, energy retention, body lipid content, tissue lipid and glycogen contents and plasma metabolites concentrations all increased significantly (P < 0.05) with increasing carbohydrate levels. Additionally, nitrogen retention (NRE), body and tissue (liver and muscle) lipid content, liver and intraperitoneal fat glycogen contents and plasma metabolites concentrations were all significantly affected (P < 0.05) by lipid sources. Hepatic and muscle monounsaturated fatty acids (MUFA) contents increased significantly (P < 0.05) with increasing carbohydrate levels, whereas the opposite was true for eicosapentaenoic acid, docosahexaenoic acid, polyunsaturated fatty acids (PUFA) and n-3 long-chain PUFA (n-3L C-PUFA) contents (P < 0.05). In terms of lipid sources, fish fed FO presented a high proportion of n-3 LC-PUFA, EPA and DHA (P < 0.05); while fish received SO and PaO obtained a high proportion of n-6 LC-PUFA and MUFA, respectively (P < 0.05). Liver glucokinase, glycogen synthase, fatty acid synthetase (FAS), acetyl-CoA carboxylase a, delta-6 fatty acyl desaturase and peroxisome proliferator-activated receptor. (PPAR.) as well as muscle pyruvate kinase (PK) expressions all increased significantly (P < 0.05) with increasing carbohydrate levels, whereas the opposite was true for the transcriptions of enzymes involved in beta-oxidation and gluconeogenesis. Hepatic FAS and muscle phosphoenolpyruvate carboxykinase (PEPCK) transcriptions were significantly affected (P < 0.05) by lipid sources. Furthermore, an interaction between dietary carbohydrate levels and lipid sources was also observed in feed intake, NRE, body/tissue lipid and glycogen contents, plasma lipids, tissue MUFA, PUFA, n-3 LC-PUFA and n-6 LC-PUFA contents as well as the transcriptions of enzymes involved in glucose and lipid metabolism (P < 0.05). Overall, these findings suggested that blunt snout bream can efficiently utilize various lipid sources at different carbohydrate levels. Dietary carbohydrate levels and lipid sources as well as their interaction significantly affected nutrient retention, tissue lipid and glycogen contents, plasma metabolites, tissue FA profiles and the intermediary metabolism, but not growth and feed efficiency.
- 出版日期2017-12-1
- 单位南京农业大学
