Biological impact and importance of functional amino acids in pig nutrition
Abstract
Increasing pig productivity and maintaining animal health without the use of antibiotics and other growth stimulants are key challenges in modern pig farming. In addition to the long-standing ban on the use of antibiotics in livestock farming, in 2022, the EU also introduced a ban on the use of zinc oxide in piglet feeding due to the environmental contamination risks. In order to overcome the food deficit and improve the overall productivity of the industry, selective breeding is being carried out in pig farming to enhance the litter size of sows. However, this often leads to the birth of a large number of small piglets that require special care to ensure adequate nutrition to support their growth and development. One such approach is the use of functional amino acids in animal feeding, as recent studies have shown the impact of amino acids on metabolism and the body as a whole, their utilization, exchange, and application to improve productivity, health, and animal well-being. The correct selection and use of functional amino acids in pig feeding can contribute not only to increased productivity but also to improved product quality and reproductive performance. The aim of this review was to summarize data from the last 10 – 15 years regarding the use of functional amino acids in the feeding of pigs from various groups. An analysis of the literature showed that the use of functional amino acids in pig feeding can enhance their productivity and serve as an alternative to banned substances, especially during critical periods of life, as well as for stimulating growth and productivity in animals.References
Badawy, A. A. (2015). Tryptophan metabolism, disposition and utilization in pregnancy. Bioscience Reports, 35(5), e00261.
Bahri, S., Zerrouk, N., Aussel, C., Moinard, C., Crenn, P., Curis, E., Chaumeil, J. C., Cynober, L., & Sfar, S. (2013). Citrulline: from metabolism to therapeutic use. Nutrition, 29(3), 479–484.
Bai, M., Liu, H., Xu, K., Oso, A. O., Wu, X., Liu, G., Tossou, M. C., Al-Dhabi, N. A., Duraipandiyan, V., Xi, Q., & Yin, Y. (2017). A review of the immunomodulatory role of dietary tryptophan in livestock and poultry. Amino Acids, 49(1), 67–74.
Bao, P., Chen, L., Wang, Y., Hu, Y., Wang, Y., Fang, H., Yang, H., Zhang, B., He, B., & Zhou, C. (2021). Quality of frozen porcine Longissimus lumborum muscles injected with l-arginine and l-lysine solution. Meat Science, 179, 108530.
Beaumont, M., Lencina, C., Painteaux, L., Viémon-Desplanque, J., Phornlaphat, O., Lambert, W., & Chalvon-Demersay, T. (2022). A mix of functional amino acids and grape polyphenols promotes the growth of piglets, modulates the gut microbiota in vivo and regulates epithelial homeostasis in intestinal organoids. Amino Acids, 54(10), 1357–1369.
Blachier, F., Wu, G., &Yin, Y. (2013) Nutritional and physiological functions of amino acids in pigs. Springer, Wien.
Blavi, L., Solà-Oriol, D., Llonch, P., López-Vergé, S., Martín-Orúe, S. M., & Pérez, J. F. (2021). Management and feeding strategies in early life to increase piglet performance and welfare around weaning: A review. Animals, 11(2), 302.
Caldow, M. K., Ham, D. J., Trieu, J., Chung, J. D., Lynch, G. S., & Koopman, R. (2019). Glycine protects muscle cells from wasting in vitro via mTORC1 signaling. Frontiers in Nutrition, 6, 172.
Cemin, H. S., Tokach, M. D., Woodworth, J. C., Dritz, S. S., DeRouchey, J. M., & Goodband, R. D. (2019). Branched-chain amino acid interactions in growing pig diets. Translational Animal Science, 3(4), 1246–1253.
Chalvon-Demersay, T., Luise, D., Le Floc'h, N., Tesseraud, S., Lambert, W., Bosi, P., Trevisi, P., Beaumont, M., & Corrent, E. (2021). Functional amino acids in pigs and chickens: Implication for gut health. Frontiers in Veterinary Science, 8, 663727.
Chowdhury, V. S., Ouchi, Y., Han, G., Eltahan, H. M., Haraguchi, S., Miyazaki, T., Shiraishi, J. I., Sugino, T., & Bungo, T. (2021). Oral administration of L-citrulline changes the concentrations of plasma hormones and biochemical profile in heat-exposed broilers. Animal Science Journal, 92(1), e13578.
Columbus, D. A., Fiorotto, M. L., & Davis, T. A. (2015). Leucine is a major regulator of muscle protein synthesis in neonates. Amino Acids, 47(2), 259–270.
Du, J., Gan, M., Xie, Z., Zhou, C., Jing, Y., Li, M., Liu, C., Wang, M., Dai, H., Huang, Z., Chen, L., Zhao, Y., Niu, L., Wang, Y., Zhang, S., Guo, Z., Shen, L., & Zhu, L. (2023). Effects of dietary L-citrulline supplementation on growth performance, meat quality, and fecal microbial composition in finishing pigs. Frontiers in Microbiology, 14, 1209389.
França, I., Valini, G. A. C., Arnaut, P. R., Ortiz, M. T., Silva, C. A., Oliveira, M. J. K., Paulino, G. S. C., Marçal, D. A., Melo, A. D. B., Htoo, J. K., Brand, H. G., Andreta, I., & Hauschild, L. (2024). Dietary supplementation with functional amino acids improves the capacity of growing pigs to cope with a health challenge. Animal Feed Science and Technology, 318, 116–148.
Gonzalez-Añover, P., & Gonzalez-Bulnes, A. (2017). Maternal age modulates the effects of early-pregnancy L-proline supplementation on the birth-weight of piglets. Animal Reproduction Science, 181, 63–68.
Greiner, L., Humphrey, D., Kerr, B., Becker, S., Breuer, S., Hagen, C., Elefson, S., & Haydon, K. (2023). Water- and feed-based arginine impacts on gut integrity in weanling pigs. Translational Animal Science, 7(1), txad059.
Habibi, M., Shili, C., Sutton, J., Goodarzi, P., Maylem, E. R., Spicer, L., & Pezeshki, A. (2021). Branched-chain amino acids partially recover the reduced growth of pigs fed with protein-restricted diets through both central and peripheral factors. Animal Nutrition, 7(3), 868–882.
Hagen, C., Humphrey, D., Wileman, C., Haydon, K., & Greiner, L. (2024). Impact of increasing dietary standardized ileal digestible arginine to lysine ratio from 0.85 to 1.15 and water-based arginine supplementation on growth performance and gut integrity of weaned pigs. Translational Animal Science, 8, txae102.
Haynes, T. E., Li, P., Li, X., Shimotori, K., Sato, H., Flynn, N. E., Wang, J., Knabe, D. A., & Wu, G. (2009). L-Glutamine or L-alanyl-L-glutamine prevents oxidant- or endotoxin-induced death of neonatal enterocytes. Amino Acids, 37(1), 131–142.
He, W., Hou, Y., & Wu, G. (2019b). 253 Glutamate and glutamine are the major metabolic fuels in enterocytes of suckling piglets. Journal of Animal Science, 97(S3), 68.
He, W., Posey, E. A., & Wu, G. (2019а). 127 Dietary supplementation with glycine improves the post-weaning growth of low-birth-weight pigs. Journal of Animal Science, 97(S3), 112.
He, W., Posey, E. A., Steele, C. C., Savell, J. W., Bazer, F. W., & Wu, G. (2024). Dietary glycine supplementation enhances glutathione availability in tissues of pigs with intrauterine growth restriction. Journal of Animal science, 102, skae025.
He, W., Posey, E., Steele, C., Savell, J., Bazer, F., & Wu, G. (2023). Dietary glycine supplementation enhances postweaning growth and meat quality of pigs with intrauterine growth restriction, Journal of Animal Science, 101, skad354.
Hodkovicova, N., Halas, S., Tosnerova, K., Stastny, K., & Svoboda, M. (2023). The use of functional amino acids in different categories of pigs – A review. Veterinarni Medicina, 68(8), 299–312.
Hou, Y., & Wu, G. (2018a). Nutritionally essential amino acids. Advances in Nutrition, 9(6), 849–851.
Hou, Y., & Wu, G. (2018b). L-Glutamate nutrition and metabolism in swine. Amino Acids, 50(11), 1497–1510.
Hou, Y., He, W., Hu, S., & Wu, G. (2019). Composition of polyamines and amino acids in plant-source foods for human consumption. Amino Acids, 51(8), 1153–1165.
Hou, Y., Yao, K., Yin, Y., & Wu, G. (2016). Endogenous synthesis of amino acids limits growth, lactation, and reproduction in animals. Advances in Nutrition, 7(2), 331–342.
Hu, C. J., Jiang, Q. Y., Zhang, T., Yin, Y. L., Li, F. N., Deng, J. P., Wu, G. Y., & Kong, X. F. (2017). Dietary supplementation with arginine and glutamic acid modifies growth performance, carcass traits, and meat quality in growing-finishing pigs. Journal of Animal Science, 95(6), 2680–2689.
Hu, C., Li, F., Duan, Y., Kong, X., Yan, Y., Deng, J., Tan, C., Wu, G., & Yin, Y. (2019). Leucine alone or in combination with glutamic acid, but not with arginine, increases biceps femoris muscle and alters muscle AA transport and concentrations in fattening pigs. Journal of Animal Physiology and Animal Nutrition, 103(3), 791–800.
Hu, S., He, W., Bazer, F. W., Johnson, G. A., & Wu, G. (2023). Synthesis of glycine from 4-hydroxyproline in tissues of neonatal pigs. Experimental Biology and Medicine, 248(14), 1206–1220.
Hu, S., Li, X., Rezaei, R., Meininger, C. J., Mc Neal, C. J., & Wu, G. (2015). Safety of long-term dietary supplementation with L-arginine in pigs. Amino Acids, 47(5), 925–936.
Humphrey, D. C., Haydon, K., & Greiner, L. L. (2023). Evaluation of branched-chain amino acid interactions in 10 to 20 kg nursery pigs using a central composite design. Journal of Animal Science, 101, skad253.
Ji, Y., Fan, X., Zhang, Y., Li, J., Dai, Z., & Wu, Z. (2022). Glycine regulates mucosal immunity and the intestinal microbial composition in weaned piglets. Amino Acids, 54(3), 385–398.
Kang, P., Zhang, L., Hou, Y., Ding, B., Yi, D., Wang, L., Zhu, H., Liu, Y., Yin, Y., & Wu, G. (2014). Effects of L-proline on the growth performance, and blood parameters in weaned lipopolysaccharide (LPS)-challenged pigs. Asian-Australasian Journal of Animal Sciences, 27(8), 1150–1156.
Kim S. W., Mateo R. D., Yin Y. L., & Wu, G. (2007) Functional amino acids and fatty acids for enhancing production performance of sows and piglets. Asian-Australasian Journal of Animal Sciences, 20(2), 295–306.
Kim, S. W., & Wu, G. (2004). Dietary arginine supplementation enhances the growth of milk-fed young pigs. The Journal of Nutrition, 134(3), 625–630.
Kong, X. F., Zhou, X. L., Feng, Z. M., Li, F. N., Ji, Y. J., Tan, B. E., Liu, Y. Y., Geng, M. M., Wu, G. Y., Blachier, F., & Yin, Y. L. (2015) Dietary supplementation with monosodium L-glutamate modifies lipid composition and gene expression related to lipid metabolism in growing pigs fed a normal- or high-fat diet. Livestock Science, 180, 247–252.
Kvidera, S. K., Mayorga, E. J., McCarthy, C. S., Horst, E. A., Abeyta, M. A., & Baumgard, L. H. (2024). Effects of supplemental citrulline on thermal and intestinal morphology parameters during heat stress and feed restriction in growing pigs. Journal of Animal Science, 102, skae120.
Le Floc’h, N., Wessels, A., Corrent, E., Wu, G., & Bosi, P. (2018). The relevance of functional amino acids to support the health of growing pigs. Animal Feed Science and Technology, 245, 104–116.
Le Floc'h, N., Gondret, F., Matte, J. J., & Quesnel, H. (2012). Towards amino acid recommendations for specific physiological and patho-physiological states in pigs. The Proceedings of the Nutrition Society, 71(3), 425–432.
Li, P., & Wu, G. (2018). Roles of dietary glycine, proline, and hydroxyproline in collagen synthesis and animal growth. Amino Acids, 50(1), 29–38.
Li, P., & Wu, G. (2020). Composition of amino acids and related nitrogenous nutrients in feedstuffs for animal diets. Amino Acids, 52(4), 523–542.
Li, P., Knabe, D. A., Kim, S. W., Lynch, C. J., Hutson, S. M., & Wu, G. (2009). Lactating porcine mammary tissue catabolizes branched-chain amino acids for glutamine and aspartate synthesis. The Journal of Nutrition, 139(8), 1502–1509.
Li, Y. H., Li, F. N., Wu, L., Liu, Y. Y., Wei, H. K., Li, T. J., Tan, B. E., Kong, X. F., Wu, F., Duan, Y. H., Oladele, O. A., & Yin, Y. L. (2017). Reduced dietary protein level influences the free amino acid and gene expression profiles of selected amino acid transceptors in skeletal muscle of growing pigs. Journal of Animal Physiology and Animal Nutrition, 101(1), 96–104.
Li, Y., Han, H., Yin, J., He, X., Tang, Z., Li, T., Yao, K., & Yin, Y. (2019). D- and L-aspartate regulates growth performance, inflammation and intestinal microbial community in young pigs. Food and Function, 10(2), 1028–1037.
Li, Y., Han, H., Yin, J., Zheng, J., Zhu, X., Li, T., & Yin, Y. (2018). Effects of glutamate and aspartate on growth performance, serum amino acids, and amino acid transporters in piglets. Food and Agricultural Immunology, 29(1), 675–687.
Liang, H., Dai, Z., Kou, J., Sun, K., Chen, J., Yang, Y., Wu, G., & Wu, Z. (2018b). Dietary L-tryptophan supplementation enhances the intestinal mucosal barrier function in weaned piglets: Implication of tryptophan-metabolizing microbiota. International Journal of Molecular Sciences, 20(1), 20.
Liang, H., Dai, Z., Liu, N., Ji, Y., Chen, J., Zhang, Y., Yang, Y., Li, J., Wu, Z., & Wu, G. (2018a). Dietary L-tryptophan modulates the structural and functional composition of the intestinal microbiome in weaned piglets. Frontiers in Microbiology, 9, 1736.
Liang, M., Wang, Z., Li, H., Cai, L., Pan, J., He, H., Wu, Q., Tang, Y., Ma, J., & Yang, L. (2018c). L-arginine induces antioxidant response to prevent oxidative stress via stimulation of glutathione synthesis and activation of Nrf2 pathway. Food and Chemical Toxicology, 115, 315–328.
Liu, B., Jiang, X., Cai, L., Zhao, X., Dai, Z., Wu, G., & Li, X. (2019b). Putrescine mitigates intestinal atrophy through suppressing inflammatory response in weanling piglets. Journal of Animal Science and Biotechnology, 10, 69.
Liu, F., de Ruyter, E. M., Athorn, R. Z., Brewster, C. J., Henman, D. J., Morrison, R. S., Smits, R. J., Cottrell, J. J., & Dunshea, F. R. (2019a). Effects of L-citrulline supplementation on heat stress physiology, lactation performance and subsequent reproductive performance of sows in summer. Journal of Animal Physiology and Animal Nutrition, 103(1), 251–257.
Mao, X., Liu, M., Tang, J., Chen, H., Chen, D., Yu, B., He, J., Yu, J., & Zheng, P. (2015). Dietary leucine supplementation improves the mucin production in the jejunal mucosa of the weaned pigs challenged by porcine rotavirus. PloS One, 10(9), e0137380.
Modina, S. C., Polito, U., Rossi, R., Corino, C., & Di Giancamillo, A. (2019). Nutritional regulation of gut barrier integrity in weaning piglets. Animals, 9(12), 1045.
Mou, Q., Yang, H. S., Yin, Y. L., & Huang, P. F. (2019). Amino acids influencing intestinal development and health of the piglets. Animals, 9(6), 302.
Munn, A. L., Weaver, A. C., & van Wettere, W. H. E. J. (2021). Supplementary tryptophan fed to sows prior to and after farrowing to improve piglet growth and survival. Animals, 11(9), 2540.
Neis, E. P., Dejong, C. H., & Rensen, S. S. (2015). The role of microbial amino acid metabolism in host metabolism. Nutrients, 7(4), 2930–2946.
Nie, C., He, T., Zhang, W., Zhang, G., & Ma, X. (2018). Branched chain amino acids: Beyond nutrition metabolism. International Journal of Molecular Sciences, 19(4), 954.
Nuntapaitoon, M., Muns, R., Theil, P. K., & Tummaruk, P. (2018). L-Arginine supplementation in sow diet during late gestation decrease stillborn piglet, increase piglet birth weight and increase immunoglobulin G concentration in colostrum. Theriogenology, 121, 27–34.
Pejsak, Z., Kaźmierczak, P., Butkiewicz, A. F., Wojciechowski, J., & Woźniakowski, G. (2023). Alternatives to zinc oxide in pig production. Polish Journal of Veterinary Sciences, 26(2), 319–330.
Perez-Palencia, J. Y., Ramirez-Camba, C. D., Haydon, K., Urschel, K. L., & Levesque, C. L. (2024). Effects of increasing dietary arginine supply during the three first weeks after weaning on pig growth performance, plasma amino acid concentrations, and health status. Translational Animal Science, 8, txae047.
Pi, D., Liu, Y., Shi, H., Li, S., Odle, J., Lin, X., Zhu, H., Chen, F., Hou, Y., & Leng, W. (2014). Dietary supplementation of aspartate enhances intestinal integrity and energy status in weanling piglets after lipopolysaccharide challenge. The Journal of Nutritional Biochemistry, 25(4), 456–462.
Prates, J. A. M., Freire, J. P. B., de Almeida, A. M., Martins, C., Ribeiro, D. M., Osório, H., Pinho, M. A. S., Lopes, P. A., Correia, J. M. J., Pinto, R. M. A., Costa, T., Corrent, E., & Chalvon-Demersay, T. (2021). Influence of dietary supplementation with an amino acid mixture on inflammatory markers, immune status and serum proteome in LPS-challenged weaned piglets. Animals, 11(4), 1143.
Rezaei, R., Knabe, D. A., Tekwe, C. D., Dahanayaka, S., Ficken, M. D., Fielder, S. E., Eide, S. J., Lovering, S. L., & Wu, G. (2013а). Dietary supplementation with monosodium glutamate is safe and improves growth performance in postweaning pigs. Amino Acids, 44(3), 911–923.
Rezaei, R., Wang, W., Wu, Z., Dai, Z., Wang, J., & Wu, G. (2013b). Biochemical and physiological bases for utilization of dietary amino acids by young pigs. Journal of Animal Science and Biotechnology, 4(1), 7.
Sales, F., Pacheco, D., Blair, H., Kenyon, P., & McCoard, S. (2013). Muscle free amino acid profiles are related to differences in skeletal muscle growth between single and twin ovine fetuses near term. SpringerPlus, 2, 483.
Santos de Aquino, R., Dutra Junior, W. M., Manso, H. E. C. C., Manso Filho, H. C., Kutschenko, M., Nogueira, E., & Watford, M. (2014). Glutamine and glutamate (AminoGut) supplementation influences sow colostrum and mature milk composition. Livestock Science, 169, 112–117.
Self, J. T., Spencer, T. E., Johnson, G. A., Hu, J., Bazer, F. W., & Wu, G. (2004). Glutamine synthesis in the developing porcine placenta. Biology of Reproduction, 70(5), 1444–1451.
Shimomura, Y., Kitaura, Y., Kadota, Y., Ishikawa, T., Kondo, Y., Xu, M., Ota, M., Morishita, Y., Bariuan, J. V., & Zhen, H. (2015). Novel physiological functions of branched-chain amino acids. Journal of Nutritional Science and Vitaminology, 61S, S112–S114.
Sommer, F., Anderson, J. M., Bharti, R., Raes, J., & Rosenstiel, P. (2017). The resilience of the intestinal microbiota influences health and disease. Nature Reviews, Microbiology, 15(10), 630–638.
Spring, S., Premathilake, H., DeSilva, U., Shili, C., Carter, S., & Pezeshki, A. (2020). Low protein-high carbohydrate diets alter energy balance, gut microbiota composition and blood metabolomics profile in young pigs. Scientific Reports, 10(1), 3318.
Sun, Y., Wu, Z., Li, W., Zhang, C., Sun, K., Ji, Y., Wang, B., Jiao, N., He, B., Wang, W., Dai, Z., & Wu, G. (2015). Dietary L-leucine supplementation enhances intestinal development in suckling piglets. Amino Acids, 47(8), 1517–1525.
Sychov, M., Ilchuk, I., Umanets, D., Balanchuk, I., Ibatullin, I., Umanets, R., Holubieva, T., Otchenashko, V., Kondratiuk, V., Tytariova, O., Kuzmenko, O., & Orishchuk, O. (2022). Slaughter parameters of broiler chickens at different levels and ratios of arginine and lysine in the compound feed. Acta Fytotechnica et Zootechnica, 25(4), 285–293.
Tan, B., Yin, Y., Liu, Z., Li, X., Xu, H., Kong, X., Huang, R., Tang, W., Shinzato, I., Smith, S. B., & Wu, G. (2009). Dietary L-arginine supplementation increases muscle gain and reduces body fat mass in growing-finishing pigs. Amino Acids, 37(1), 169–175.
Tan, C., Huang, Z., Xiong, W., Ye, H., Deng, J., & Yin, Y. (2022). A review of the amino acid metabolism in placental function response to fetal loss and low birth weight in pigs. Journal of Animal Science and Biotechnology, 13(1), 28.
Tan, X., Zhang, J., Yang, H., Li, J., Li, Y., Ding, X., Huang, P., Wang, Q., Yin, J., & Yin, Y. (2019). Glutamate effects on sucking piglet intestinal morphology and luminal metabolites. Journal of Animal Physiology and Animal Nutrition, 103(2), 612–617.
Uyanga, V. A., Wang, M., Tong, T., Zhao, J., Wang, X., Jiao, H., Onagbesan, O. M., & Lin, H. (2021). L-Citrulline influences the body temperature, heat shock response and nitric oxide regeneration of broilers under thermoneutral and heat stress condition. Frontiers in Physiology, 12, 671691.
Wang, A., Keita, A. V., Phan, V., McKay, C. M., Schoultz, I., Lee, J., Murphy, M. P., Fernando, M., Ronaghan, N., Balce, D., Yates, R., Dicay, M., Beck, P. L., MacNaughton, W. K., Soderholm, J. D., & McKay, D. M. (2014a). Targeting mitochondria-derived reactive oxygen species to reduce epithelial barrier dysfunction and colitis. The American Journal of Pathology, 184, 2516–2527.
Wang, B., Sun, S., Liu, M., Chen, H., Liu, N., Wu, Z., Wu, G., & Dai, Z. (2020). Dietary L-tryptophan regulates colonic serotonin homeostasis in mice with dextran sodium sulfate-induced colitis. The Journal of Nutrition, 150(7), 1966–1976.
Wang, C. X., Chen, F., Zhang, W. F., Zhang, S. H., Shi, K., Song, H. Q., Wang, Y. J., Kim, S. W., & Guan, W. T. (2018). Leucine promotes the growth of fetal pigs by increasing protein synthesis through the mTOR signaling pathway in longissimus dorsi muscle at late gestation. Journal of Agricultural and Food Chemistry, 66(15), 3840–3849.
Wang, H., Zhang, C., Wu, G., Sun, Y., Wang, B., He, B., Dai, Z., & Wu, Z. (2015b). Glutamine enhances tight junction protein expression and modulates corticotropin-releasing factor signaling in the jejunum of weanling piglets. The Journal of Nutrition, 145(1), 25–31.
Wang, J., Chen, L., Li, P., Li, X., Zhou, H., Wang, F., Li, D., Yin, Y., & Wu, G. (2008). Gene expression is altered in piglet small intestine by weaning and dietary glutamine supplementation. The Journal of Nutrition, 138(6), 1025–1032.
Wang, W., Dai, Z., Wu, Z., Lin, G., Jia, S., Hu, S., Dahanayaka, S., & Wu, G. (2014b). Glycine is a nutritionally essential amino acid for maximal growth of milk-fed young pigs. Amino Acids, 46(8), 2037–2045.
Wang, X., Liu, Y., Li, S., Pi, D., Zhu, H., Hou, Y., Shi, H., & Leng, W. (2015a). Asparagine attenuates intestinal injury, improves energy status and inhibits AMP-activated protein kinase signalling pathways in weaned piglets challenged with Escherichia coli lipopolysaccharide. The British Journal of Nutrition, 114(4), 553–565.
Watford, M., & Wu, G. (2018). Protein. Advances in Nutrition, 9(5), 651–653.
Wessels, A. G., Kluge, H., Hirche, F., Kiowski, A., Schutkowski, A., Corrent, E., Bartelt, J., König, B., & Stangl, G. I. (2016). High leucine diets stimulate cerebral branched-chain amino acid degradation and modify serotonin and ketone body concentrations in a pig model. PloS One, 11(3), e0150376.
Wijnands, K. A., Vink, H., Briedé, J. J., van Faassen, E. E., Lamers, W. H., Buurman, W. A., & Poeze, M. (2012). Citrulline a more suitable substrate than arginine to restore NO production and the microcirculation during endotoxemia. PloS One, 7(5), e37439.
Wilkinson, D. J., Hossain, T., Hill, D. S., Phillips, B. E., Crossland, H., Williams, J., Loughna, P., Churchward-Venne, T. A., Breen, L., Phillips, S. M., Etheridge, T., Rathmacher, J. A., Smith, K., Szewczyk, N. J., & Atherton, P. J. (2013). Effects of leucine and its metabolite β-hydroxy-β-methylbutyrate on human skeletal muscle protein metabolism. The Journal of Physiology, 591(11), 2911–2923.
Wu, G. (2017). Principles of animal nutrition. CRC Press, Boca Raton.
Wu, G. (2021). Amino acids: Biochemistry and nutrition. 2st ed. CRC Press, Boca Raton.
Wu, G., Bazer, F. W., Johnson, G. A., & Hou, Y. (2018). Board-invited review: Arginine nutrition and metabolism in growing, gestating, and lactating swine. Journal of Animal Science, 96(12), 5035–5051.
Wu, G., Bazer, F. W., Johnson, G. A., Knabe, D. A., Burghardt, R. C., Spencer, T. E., Li, X. L., & Wang, J. J. (2011a). Triennial growth symposium: Important roles for L-glutamine in swine nutrition and production. Journal of Animal Science, 89(7), 2017–2030.
Wu, Z., Hou, Y., Dai, Z., Hu, C. A., & Wu, G. (2019). Metabolism, nutrition, and redox signaling of hydroxyproline. Antioxidants and Redox Signaling, 30(4), 674–682.
Yang, Y., Hou, G., Ji, F., Zhou, H., Lv, R., & Hu, C. (2024). Maternal supplementation with ornithine promotes placental angiogenesis and improves intestinal development of suckling piglets. Animals, 14(5), 689.
Yang, Y., Li, W., Sun, Y., Han, F., Hu, C. A., & Wu, Z. (2015). Amino acid deprivation disrupts barrier function and induces protective autophagy in intestinal porcine epithelial cells. Amino Acids, 47(10), 2177–2184.
Yi, D., Li, B., Hou, Y., Wang, L., Zhao, D., Chen, H., Wu, T., Zhou, Y., Ding, B., & Wu, G. (2018). Dietary supplementation with an amino acid blend enhances intestinal function in piglets. Amino Acids, 50(8), 1089–1100.
Yin, J., Ma, J., Li, Y., Ma, X., Chen, J., Zhang, H., Wu, X., Li, F., Liu, Z., Li, T., & Yin, Y. (2020). Branched-chain amino acids, especially of leucine and valine, mediate the protein restricted response in a piglet model. Food and Function, 11(2), 1304–1311.
Ytrebo, L. M., Sen, S., Rose, C., Ten Have, G. A., Davies, N. A., Hodges, S., Nedredal, G. I., Romero-Gomez, M., Williams, R., Revhaug, A., Jalan, R., & Deutz, N. E. (2006). Interorgan ammonia, glutamate, and glutamine trafficking in pigs with acute liver failure. American Journal of Physiology, Gastrointestinal and Liver Physiology, 291(3), G373–G381.
Yu, D., Zhu, W., & Hang, S. (2019). Effects of low-protein diet on the intestinal morphology, digestive enzyme activity, blood urea nitrogen, and gut microbiota and metabolites in weaned pigs. Archives of Animal Nutrition, 73(4), 287–305.
Zhang, Q., Hou, Y., Bazer, F. W., He, W., Posey, E. A., & Wu, G. (2021). Amino acids in swine nutrition and production. Advances in Experimental Medicine and Biology, 1285, 81–107.
Zhang, S., Chu, L., Qiao, S., Mao, X., & Zeng, X. (2016). Effects of dietary leucine supplementation in low crude protein diets on performance, nitrogen balance, whole-body protein turnover, carcass characteristics and meat quality of finishing pigs. Animal Science Journal, 87(7), 911–920.
Zhang, Y., Lu, T., Han, L., Zhao, L., Niu, Y., & Chen, H. (2017). L-Glutamine supplementation alleviates constipation during late gestation of mini sows by modifying the microbiota composition in feces. BioMed Research International, 2017, 4862861.
Zheng, P., Song, Y., Tian, Y., Zhang, H., Yu, B., He, J., Mao, X., Yu, J., Luo, Y., Luo, J., Huang, Z., Tian, G., Chen, H., & Chen, D. (2018). Dietary arginine supplementation affects intestinal function by enhancing antioxidant capacity of a nitric oxide-independent pathway in low-birth-weight piglets. The Journal of Nutrition, 148(11), 1751–1759.
Zhu, C., Guo, C., Gao, K., Wang, L., Chen, Z., Ma, X., & Jiang, Z. (2017). Dietary arginine supplementation in multiparous sows during lactation improves the weight gain of suckling piglets. Journal of Integrative Agriculture, 16(3), 648–655.
Zhu, Y., Li, T., Huang, S., Wang, W., Dai, Z., Feng, C., Wu, G., & Wang, J. (2018). Maternal L-glutamine supplementation during late gestation alleviates intrauterine growth restriction-induced intestinal dysfunction in piglets. Amino Acids, 50(9), 1289–1299.
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