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He W, Posey EA, Steele CC, Savell JW, Bazer FW, Wu G. Dietary glycine supplementation activates mechanistic target of rapamycin signaling pathway in tissues of pigs with intrauterine growth restriction. J Anim Sci 2024; 102:skae141. [PMID: 38761109 DOI: 10.1093/jas/skae141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Accepted: 05/16/2024] [Indexed: 05/20/2024] Open
Abstract
The mechanistic target of rapamycin (mTOR) cell signaling pathway serves as the central mechanism for the regulation of tissue protein synthesis and growth. We recently reported that supplementing 1% glycine to corn- and soybean meal-based diets enhanced growth performance between weaning and market weights in pigs with intrauterine growth restriction (IUGR). Results of recent studies have revealed an important role for glycine in activating mTOR and protein synthesis in C2C12 muscle cells. Therefore, the present study tested the hypothesis that dietary glycine supplementation enhanced the mTOR cell signaling pathway in skeletal muscle and other tissues of IUGR pigs. At weaning (21 d of age), IUGR pigs and litter mates with normal birth weights (NBW) were assigned randomly to one of the two groups: supplementation with either 1% glycine or 1.19% l-alanine (isonitrogenous control) to a corn- and soybean meal-based diet. Tissues were obtained from the pigs within 1 wk after the feeding trial ended at 188 d of age to determine the abundances of total and phosphorylated forms of mTOR and its two major downstream proteins: eukaryotic initiation factor 4E-binding protein-1 (4EBP1) and ribosomal protein S6 kinase-1 (p70S6K). Results showed that IUGR decreased (P < 0.05) the abundances of both total and phosphorylated mTOR, 4EBP1, and p70S6K in the gastrocnemius muscle and jejunum. In the longissimus lumborum muscle of IUGR pigs, the abundances of total mTOR did not differ (P > 0.05) but those for phosphorylated mTOR and both total and phosphorylated 4EBP1 and p70S6K were downregulated (P < 0.05), when compared to NBW pigs. These adverse effects of IUGR in the gastrocnemius muscle, longissimus lumborum muscle, and jejunum were prevented (P < 0.05) by dietary glycine supplementation. Interestingly, the abundances of total or phosphorylated mTOR, 4EBP1, and p70S6K in the liver were not affected (P > 0.05) by IUGR or glycine supplementation. Collectively, our findings indicate that IUGR impaired the mTOR cell signaling pathway in the tissues of pigs and that adequate glycine intake was crucial for maintaining active mTOR-dependent protein synthesis for the growth and development of skeletal muscle.
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Affiliation(s)
- Wenliang He
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
| | - Erin A Posey
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
| | - Chandler C Steele
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
| | - Jeffrey W Savell
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
| | - Fuller W Bazer
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
| | - Guoyao Wu
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
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Wu G. Recent Advances in the Nutrition and Metabolism of Dogs and Cats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1446:1-14. [PMID: 38625522 DOI: 10.1007/978-3-031-54192-6_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Domestic dogs (facultative carnivores) and cats (obligate carnivores) have been human companions for at least 12,000 and 9000 years, respectively. These animal species have a relatively short digestive tract but a large stomach volume and share many common features of physiological processes, intestinal microbes, and nutrient metabolism. The taste buds of the canine and feline tongues can distinguish sour, umami, bitter, and salty substances. Dogs, but not cats, possess sweet receptors. α-Amylase activity is either absent or very low in canine and feline saliva, and is present at low or substantial levels in the pancreatic secretions of cats or dogs, respectively. Thus, unlike cats, dogs have adapted to high-starch rations while also consuming animal-sourced foods. At metabolic levels, both dogs and cats synthesize de novo vitamin C and many amino acids (AAs, such as Ala, Asn, Asp, Glu, Gln, Gly, Pro, and Ser) but have a very limited ability to form vitamin D3. Compared with dogs, cats have higher requirements for AAs, some B-complex vitamins, and choline; greater rates of gluconeogenesis; a higher capacity to tolerate AA imbalances and antagonism; a more limited ability to synthesize arginine and taurine from glutamine/proline and cysteine, respectively; and a very limited ability to generate polyunsaturated fatty acids (PUFAs) from respective substrates. Unlike dogs, cats cannot convert either β-carotene into vitamin A or tryptophan into niacin. Dogs can thrive on one large meal daily and select high-fat over low-fat diets, whereas cats eat more frequently during light and dark periods and select high-protein over low-protein diets. There are increasing concerns over the health of skin, hair, bone, and joints (specialized connective tissues containing large amounts of collagen and/or keratin); sarcopenia (age-related losses of skeletal-muscle mass and function); and cognitive function in dogs and cats. Sufficient intakes of proteinogenic AAs and taurine along with vitamins, minerals, and PUFAs are crucial for the normal structures of the skin, hair, bone, and joints, while mitigating sarcopenia and cognitive dysfunction. Although pet owners may have different perceptions about the feeding and management practice of their dogs and cats, the health and well-being of the companion animals critically depend on safe, balanced, and nutritive foods. The new knowledge covered in this volume of Adv Exp Med Biol is essential to guide the formulation of pet foods to improve the growth, development, brain function, reproduction, lactation, and health of the companion animals.
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Affiliation(s)
- Guoyao Wu
- Department of Animal Science, Texas A&M University, College Station, TX, 77843, USA.
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Li P, Wu G. Characteristics of Nutrition and Metabolism in Dogs and Cats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1446:55-98. [PMID: 38625525 DOI: 10.1007/978-3-031-54192-6_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Domestic dogs and cats have evolved differentially in some aspects of nutrition, metabolism, chemical sensing, and feeding behavior. The dogs have adapted to omnivorous diets containing taurine-abundant meat and starch-rich plant ingredients. By contrast, domestic cats must consume animal-sourced foods for survival, growth, and development. Both dogs and cats synthesize vitamin C and many amino acids (AAs, such as alanine, asparagine, aspartate, glutamate, glutamine, glycine, proline, and serine), but have a limited ability to form de novo arginine and vitamin D3. Compared with dogs, cats have greater endogenous nitrogen losses and higher dietary requirements for AAs (particularly arginine, taurine, and tyrosine), B-complex vitamins (niacin, thiamin, folate, and biotin), and choline; exhibit greater rates of gluconeogenesis; are less sensitive to AA imbalances and antagonism; are more capable of concentrating urine through renal reabsorption of water; and cannot tolerate high levels of dietary starch due to limited pancreatic α-amylase activity. In addition, dogs can form sufficient taurine from cysteine (for most breeds); arachidonic acid from linoleic acid; eicosapentaenoic acid and docosahexaenoic acid from α-linolenic acid; all-trans-retinol from β-carotene; and niacin from tryptophan. These synthetic pathways, however, are either absent or limited in all cats due to (a) no or low activities of key enzymes (including pyrroline-5-carboxylate synthase, cysteine dioxygenase, ∆6-desaturase, β-carotene dioxygenase, and quinolinate phosphoribosyltransferase) and (b) diversion of intermediates to other metabolic pathways. Dogs can thrive on one large meal daily, select high-fat over low-fat diets, and consume sweet substances. By contrast, cats eat more frequently during light and dark periods, select high-protein over low-protein diets, refuse dry food, enjoy a consistent diet, and cannot taste sweetness. This knowledge guides the feeding and care of dogs and cats, as well as the manufacturing of their foods. As abundant sources of essential nutrients, animal-derived foodstuffs play important roles in optimizing the growth, development, and health of the companion animals.
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Affiliation(s)
- Peng Li
- North American Renderers Association, Alexandria, VA, 22314, USA
| | - Guoyao Wu
- Department of Animal Science, Texas A&M University, College Station, TX, 77843, USA.
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Wang F, Sun W, Liu G, Jia G, Zhao H, Chen X, Wu C, Wang J. Tryptophan alleviates lipopolysaccharide-induced muscle fiber type transformation from type I to II and modulates Sirt1/AMPK/PGC-1α signaling pathway in pigs. Anim Biotechnol 2023; 34:3135-3143. [PMID: 36346004 DOI: 10.1080/10495398.2022.2136679] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Tryptophan is a functional amino acid. This study aimed to investigate whether dietary tryptophan supplementation can alleviate Escherichia coli lipopolysaccharide (LPS)-induced skeletal muscle fiber transition from type I to type II in pigs, and the molecular mechanism was also examined. Eighteen weaned piglets were allotted to three treatments groups, namely, the nonchallenged control, LPS-challenged control and LPS + 0.2% tryptophan groups. On day 35, the pigs in the LPS and LPS + 0.2% tryptophan groups were challenged by injection with 100 μg/kg body weight (BW) LPS, whereas the control group was given sterile saline. Tryptophan can attenuate LPS-induced decrease in protein content of slow MyHC, the activities of succinic dehydrogenase, malate dehydrogenase (MDH) and antioxidant enzyme, the mRNA expression of oxidative muscle fiber-related genes, type I fiber proportion, and increase in lactate dehydrogenase (LDH) activity, the mRNA expression level of MyHC IIb and type II fiber proportion. Moreover, tryptophan supplementation attenuated LPS-induced decrease in the expression levels of phosphorylated AMP-activated protein kinase (AMPK), silent information regulator 1 (Sirt1) and peroxisome proliferator activated receptor gamma coactivator 1-alpha (PGC-1α). Collectively, tryptophan can alleviate LPS-induced muscle fiber type transformation from type I to type II. This effect is associated with activating the Sirt1/AMPK/PGC-1α signaling pathway.
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Affiliation(s)
- Fang Wang
- Institute of Animal Nutrition, Key Laboratory for Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan province, Sichuan Agricultural University, Chengdu, PR China
| | - Weixiao Sun
- Institute of Animal Nutrition, Key Laboratory for Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan province, Sichuan Agricultural University, Chengdu, PR China
| | - Guangmang Liu
- Institute of Animal Nutrition, Key Laboratory for Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan province, Sichuan Agricultural University, Chengdu, PR China
| | - Gang Jia
- Institute of Animal Nutrition, Key Laboratory for Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan province, Sichuan Agricultural University, Chengdu, PR China
| | - Hua Zhao
- Institute of Animal Nutrition, Key Laboratory for Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan province, Sichuan Agricultural University, Chengdu, PR China
| | - Xiaoling Chen
- Institute of Animal Nutrition, Key Laboratory for Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan province, Sichuan Agricultural University, Chengdu, PR China
| | - Caimei Wu
- Institute of Animal Nutrition, Key Laboratory for Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan province, Sichuan Agricultural University, Chengdu, PR China
| | - Jing Wang
- Maize Research Institute, Sichuan Agricultural University, Chengdu, PR China
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Martinez RE, Leatherwood JL, Bradbery AN, Paris BL, Hammer CJ, Kelley D, Bazer FW, Wu G. Evaluation of dietary arginine supplementation to increase placental nutrient transporters in aged mares. Transl Anim Sci 2023; 7:txad058. [PMID: 37593152 PMCID: PMC10430792 DOI: 10.1093/tas/txad058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 06/21/2023] [Indexed: 08/19/2023] Open
Abstract
Nine pregnant mares (18.2 ± 0.7 yr; 493.82 ± 12.74 kg body weight [BW]) were used to test the hypothesis that dietary supplementation of l-arginine would enhance placental vascularity and nutrient transport throughout gestation in aged mares. Mares were balanced by age, BW, and stallion pairing, and assigned randomly to dietary treatments of either supplemental l-arginine (50 mg/kg BW; n = 7) or l-alanine (100 mg/kg BW; n = 6; isonitrogenous control). Mares were individually fed concentrate top-dressed with the respective amino acid treatment plus ad libitum access to Coastal Bermudagrass hay. Treatments began on day 14 of gestation and were terminated at parturition. Mare BW, body condition score (BCS), and rump fat were determined, and body fat percentage was calculated every 28 d and concentrate adjusted accordingly. Doppler blood flow measurements including resistance index (RI) and pulsatility index for uterine artery ipsilateral to the pregnant uterine horn were obtained beginning on day 21 and continued every 7 d until day 154 of gestation, and prior to parturition. Parturition was attended with foaling variables and placental measures recorded. Placental tissue from the pregnant horn was analyzed histologically to assess cell-specific localization of vascular endothelial growth factor (VEGF) and cationic amino acid transporter 1 (SLC7A1) proteins. Semiquantitative analyses were performed using 10 nonoverlapping images per sample fixed in a 10× field (Fiji ImageJ v1.2). Mare performance data were analyzed using PROC MIXED in SAS and foaling and placental data were analyzed using PROC GLM. Gestation length at parturition was not influenced (P > 0.05) by supplemental arginine. Compared with arginine-supplemented mares, control mares had a thicker rump fat layer (P < 0.01) and greater percent body fat (P = 0.03), and BCS (P < 0.01) at parturition. Arginine-supplemented mares had a lower RI than control mares prior to parturition (P < 0.01). Body length, height, and BW of foals at birth, as well as placental weight and volume, and immunohistochemical staining for VEGF and SLC7A1 at parturition, were not affected (P > 0.05) by maternal arginine supplementation. These results indicate that dietary arginine supplementation (50 mg/kg BW) is safe for gestating mares. A larger number of mares is required to extend knowledge of effects of supplemental arginine on embryonic/fetal survival and growth in mares.
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Affiliation(s)
- Rafael E Martinez
- Department of Animal Science, Texas A&M University and Texas A&M AgriLife Research, College Station, TX 77843, USA
- School of Agricultural Sciences, Sam Houston State University, Huntsville, TX 77340, USA
| | - Jessica L Leatherwood
- Department of Animal Science, Texas A&M University and Texas A&M AgriLife Research, College Station, TX 77843, USA
- Department of Large Animal Clinical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Amanda N Bradbery
- Department of Animal and Range Sciences, Montana State University, Bozeman, MT 59717, USA
| | - Brittany L Paris
- Department of Animal Science, Texas A&M University and Texas A&M AgriLife Research, College Station, TX 77843, USA
- Department of Large Animal Clinical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Carolyn J Hammer
- Department of Animal Sciences, North Dakota State University, Fargo, ND 58102, USA
| | - Dale Kelley
- Department of Veterinary Clinical Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Fuller W Bazer
- Department of Animal Science, Texas A&M University and Texas A&M AgriLife Research, College Station, TX 77843, USA
| | - Guoyao Wu
- Department of Animal Science, Texas A&M University and Texas A&M AgriLife Research, College Station, TX 77843, USA
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L-Arginine increases AMPK phosphorylation and the oxidation of energy substrates in hepatocytes, skeletal muscle cells, and adipocytes. Amino Acids 2022; 54:1553-1568. [PMID: 35972552 DOI: 10.1007/s00726-022-03195-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 08/01/2022] [Indexed: 12/16/2022]
Abstract
Previous work has shown that dietary L-arginine (Arg) supplementation reduced white fat mass in obese rats. The present study was conducted with cell models to define direct effects of Arg on energy-substrate oxidation in hepatocytes, skeletal muscle cells, and adipocytes. BNL CL.2 mouse hepatocytes, C2C12 mouse myotubes, and 3T3-L1 mouse adipocytes were treated with different extracellular concentrations of Arg (0, 15, 50, 100 and 400 µM) or 400 µM Arg + 0.5 mM NG-nitro-L-arginine methyl ester (L-NAME; an NOS inhibitor) for 48 h. Increasing Arg concentrations in culture medium dose-dependently enhanced (P < 0.05) the oxidation of glucose and oleic acid to CO2 in all three cell types, lactate release from C2C12 cells, and the incorporation of oleic acid into esterified lipids in BNL CL.2 and 3T3-L1 cells. Arg at 400 µM also stimulated (P < 0.05) the phosphorylation of AMP-activated protein kinase (AMPK) in all three cell types and increased (P < 0.05) NO production in C2C12 and BNL CL.2 cells. The inhibition of NOS by L-NAME moderately reduced (P < 0.05) glucose and oleic acid oxidation, lactate release, and the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC) in BNL CL.2 cells, but had no effect (P > 0.05) on these variables in C2C12 or 3T3-L1 cells. Collectively, these results indicate that Arg increased AMPK activity and energy-substrate oxidation in BNL CL.2, C2C12, and 3T3-L1 cells through both NO-dependent and NO-independent mechanisms.
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