title: Effects of supplementation with branched-chain amino acids to low-protein diets on expression of genes related to lipid metabolism in skeletal muscle of growing pigs.
abstract: Branched-chain amino acids (BCAA), including leucine (Leu), isoleucine (Ile), and valine (Val), play critical roles in energy homeostasis and lipid metabolism in addition to their other functions, such as in protein metabolism. This study investigated the effects of different dietary BCAA ratios on the intramuscular fat (IMF) content and fatty acid composition in different location of skeletal muscles, including the longissimus dorsi (LD), biceps femoris (BF), and psoas major (PM) muscles of growing pigs, and also examined the mRNA expression levels of genes involved in lipid metabolism in these muscle tissues. The experiment was performed on 40 growing pigs (Large White × Landrace) with a similar initial weight (9.85 ± 0.35 kg). The pigs were randomly assigned to one of five diets: diet A was a positive control and contained 20 % crude protein (CP) with a Leu:Ile:Val ratio of 1:0.51:0.63 according to the recommendation of the National Research Council (NRC); for diets B to E, the CP level was reduced to 17 %, and the Leu:Ile:Val ratios were 1:1:1, 1:0.75:0.75, 1:0.51:0.63, and 1:0.25:0.25, respectively. No significant difference was observed in the average feed intake and feed efficiency of the pigs fed the low protein diet (17 % CP) with BCAA treatments relative to the positive control. However, there was a tendency for increased feed efficiency of the 1:0.75:0.75 group compared with the 1:1:1 group (P = 0.09). The BCAA ratio of 1:0.75:0.75 (17 % CP) increased the IMF content of BF muscle (P < 0.01). Moreover, varied dietary BCAA supplementation with a reduced protein level had different effects on the fatty acid composition of the LD, BF, and PM muscles. The BCAA ratio of 1:0.51:0.63-1:0.75:0.75 (17 % CP) significantly lowered the ratio of n-6 to n-3 polyunsaturated fatty acid in these muscles compared with the positive control group (20 % CP). This effect was associated with an increase in mRNA expression levels of acetyl-CoA carboxylase, lipoprotein lipase, fatty acid transport protein, and fatty acid binding protein 4 in the muscles (P < 0.05). The results indicated that the reduced protein diet (17 % CP) with the BCAA ratio within 1:0.25:0.25-1:0.75:0.75 could increase the IMF content in BF muscle and significantly improve the fatty acid composition in different skeletal muscles accompanied by changes in the expression of genes involved in lipid metabolism, compared with those in the pigs that received adequate dietary protein (20 %), which might result in improved eating quality and nutritional value of the meat.
authors.affiliation: Key Laboratory of Agroecology in Subtropical Region, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central China, Research Center for Healthy Breeding Livestock and Poultry, Hunan Engineering and Research Center for Animal and Poultry Science, Institute of Subtropical Agriculture, Ministry of Agriculture, Chinese Academy of Science, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China.|University of Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Yehui
authors.initials: Y
authors.lastname: Duan
authors.affiliation: University of Chinese Academy of Sciences, Beijing, 100039, China.|Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
authors.forename: Yangmiao
authors.initials: Y
authors.lastname: Duan
authors.affiliation: Key Laboratory of Agroecology in Subtropical Region, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central China, Research Center for Healthy Breeding Livestock and Poultry, Hunan Engineering and Research Center for Animal and Poultry Science, Institute of Subtropical Agriculture, Ministry of Agriculture, Chinese Academy of Science, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China. lifengna@isa.ac.cn.|Hunan Co-Innovation Center of Animal Production Safety (CICAPS), Changsha, 410125, China. lifengna@isa.ac.cn.
authors.forename: Fengna
authors.initials: F
authors.lastname: Li
authors.affiliation: Key Laboratory of Agroecology in Subtropical Region, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central China, Research Center for Healthy Breeding Livestock and Poultry, Hunan Engineering and Research Center for Animal and Poultry Science, Institute of Subtropical Agriculture, Ministry of Agriculture, Chinese Academy of Science, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China.|University of Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Li
authors.affiliation: Key Laboratory of Agroecology in Subtropical Region, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central China, Research Center for Healthy Breeding Livestock and Poultry, Hunan Engineering and Research Center for Animal and Poultry Science, Institute of Subtropical Agriculture, Ministry of Agriculture, Chinese Academy of Science, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China.|University of Chinese Academy of Sciences, Beijing, 100039, China.
authors.forename: Qiuping
authors.initials: Q
authors.lastname: Guo
authors.affiliation: Key Laboratory of Agroecology in Subtropical Region, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central China, Research Center for Healthy Breeding Livestock and Poultry, Hunan Engineering and Research Center for Animal and Poultry Science, Institute of Subtropical Agriculture, Ministry of Agriculture, Chinese Academy of Science, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China.
authors.forename: Yujiao
authors.initials: Y
authors.lastname: Ji
authors.affiliation: Key Laboratory of Agroecology in Subtropical Region, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central China, Research Center for Healthy Breeding Livestock and Poultry, Hunan Engineering and Research Center for Animal and Poultry Science, Institute of Subtropical Agriculture, Ministry of Agriculture, Chinese Academy of Science, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China.|Hunan Co-Innovation Center of Animal Production Safety (CICAPS), Changsha, 410125, China.|Hunan Collaborative Innovation Center for Utilization of Botanical Functional Ingredients, Changsha, 410128, China.
authors.forename: Bie
authors.initials: B
authors.lastname: Tan
authors.affiliation: Key Laboratory of Agroecology in Subtropical Region, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central China, Research Center for Healthy Breeding Livestock and Poultry, Hunan Engineering and Research Center for Animal and Poultry Science, Institute of Subtropical Agriculture, Ministry of Agriculture, Chinese Academy of Science, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China.
authors.forename: Tiejun
authors.initials: T
authors.lastname: Li
authors.affiliation: Key Laboratory of Agroecology in Subtropical Region, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central China, Research Center for Healthy Breeding Livestock and Poultry, Hunan Engineering and Research Center for Animal and Poultry Science, Institute of Subtropical Agriculture, Ministry of Agriculture, Chinese Academy of Science, No. 644 Yuanda Road, Furong District, Changsha, 410125, Hunan, China. yinyulong@isa.ac.cn.|Hunan Collaborative Innovation Center for Utilization of Botanical Functional Ingredients, Changsha, 410128, China. yinyulong@isa.ac.cn.|School of Biology, Hunan Normal University, Changsha, 410018, China. yinyulong@isa.ac.cn.
authors.forename: Yulong
authors.initials: Y
authors.lastname: Yin
mesh_terms: D000597:Amino Acids, Branched-Chain / Q000494:pharmacology*; D000818:Animals; D004044:Dietary Proteins / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D050356:Lipid Metabolism / Q000187:drug effects*; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000378:metabolism*; D013552:Swine / Q000254:growth & development*
chemical_list: D000597:Amino Acids, Branched-Chain; D004044:Dietary Proteins; D009124:Muscle Proteins
keywords: Branched-chain amino acid ratio; Fatty acid composition; Growing pigs; Lipid metabolism; Skeletal muscles