Abstract
High concentrate diets are fed to early and mid-lactation stages dairy ruminants to meet the energy demands for high milk production in modern milk industry. The present study evaluated the effects of a high concentrate diet on milk fat and milk composition, especially, cis-9, trans-11 CLA content in milk and gene expression of lactating goats. Eight mid-lactating goats with rumen fistula were randomly assigned into a high concentrate diet (HCD) group and low concentrate diet (LCD) group. High concentrate diet feeding significantly increased lipopolysaccharides (LPS) in plasma and decreased milk fat content, vaccenic acid (VA) and cis-9, trans-11 CLA in milk of the lactating goats. The mRNA expression levels of sterol regulatory element binding protein B 1c (SREBP1c), lipoprotein lipase (LPL), fatty acid synthetase (FASN) and acetyl-CoA carboxylase α (ACACA, ACCα) involving in lipid metabolism were analyzed, and ACACA and LPL all decreased in their expression level in the mammary glands of goats fed a high concentrate diet. DNA methylation rate of stearoyl-CoA desaturase (SCD) was elevated and decreased, and SCD mRNA and protein expression was reduced significantly in the mammary glands of goats fed a high concentrate diet. In conclusion, feeding a high concentrate diet to lactating goats decreases milk fat and reduced expression of SCD in the mammary gland, which finally induced cis-9, trans-11 CLA content in milk.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Acetyl-CoA Carboxylase / genetics
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Acetyl-CoA Carboxylase / metabolism*
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Animals
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DNA Methylation
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Diet / veterinary*
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Down-Regulation
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Fatty Acid Synthases / genetics
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Fatty Acid Synthases / metabolism
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Fatty Acids / analysis
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Female
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Goats
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Isomerism
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Lactation
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Linoleic Acids, Conjugated / metabolism
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Lipopolysaccharides / blood
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Lipoprotein Lipase / genetics
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Lipoprotein Lipase / metabolism*
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Mammary Glands, Animal / metabolism
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Milk / metabolism*
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Oleic Acids / metabolism
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Rumen / metabolism
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Stearoyl-CoA Desaturase / genetics
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Stearoyl-CoA Desaturase / metabolism*
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Sterol Regulatory Element Binding Protein 1 / genetics
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Sterol Regulatory Element Binding Protein 1 / metabolism
Substances
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Fatty Acids
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Linoleic Acids, Conjugated
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Lipopolysaccharides
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Oleic Acids
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Sterol Regulatory Element Binding Protein 1
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Stearoyl-CoA Desaturase
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Fatty Acid Synthases
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Lipoprotein Lipase
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Acetyl-CoA Carboxylase
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11-octadecenoic acid
Grants and funding
This study was supported by the National Basic Research Program of China (2011CB100802), National Natural Science Foundation of China (31172371; 30371040), the Federal Ministry of Food, Agriculture and Consumer Protection of Germany, the Ministry of Agriculture of China (Grant No. 30/2008-2009), and the Priority Academic Program Development of Jinagsu Higher Education Institutions. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.