Triennial Growth Symposium: important roles for L-glutamine in swine nutrition and production.
ABSTRACT L-Glutamine (Gln) has traditionally not been considered a nutrient needed in diets for livestock species or even mentioned in classic animal nutrition textbooks. This is due to previous technical difficulties in Gln analysis and the unsubstantiated assumption that animals can synthesize sufficient amounts of Gln to meet their needs. Consequently, the current (1998) version of NRC does not recommend dietary Gln requirements for swine. This lack of knowledge about Gln nutrition has contributed to suboptimal efficiency of global pig production. Because of recent advances in research, Gln is now known to be an abundant AA in physiological fluids and proteins and a key regulator of gene expression. Additionally, Gln can regulate cell signaling via the mammalian target of rapamycin pathway, adenosine monophosphate-activated protein kinase, extracellular signal-related kinase, Jun kinase, mitogen-activated protein kinase, and nitric oxide. The exquisite integration of Gln-dependent regulatory networks has profound effects on cell proliferation, differentiation, migration, metabolism, homeostasis, survival, and function. As a result of translating basic research into practice, dietary supplementation with 1% Gln maintains gut health and prevents intestinal dysfunction in low-birth-weight or early-weaned piglets while increasing their growth performance and survival. In addition, supplementing 1% Gln to a corn- and soybean-meal-based diet between d 90 and 114 of gestation ameliorates fetal growth retardation in gilts and reduces preweaning mortality of piglets. Furthermore, dietary supplementation with 1% Gln enhances milk production by lactating sows. Thus, adequate amounts of dietary Gln, a major nutrient, are necessary to support the maximum growth, development, and production performance of swine.
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Article: Functional roles of fructose.[Show abstract] [Hide abstract]
ABSTRACT: During the periimplantation period of pregnancy, pig blastocysts undergo morphological changes and differentiation requiring secretion and transport of nutrients (histotroph) into the uterine lumen. Of these nutrients, glucose is converted to fructose, an isomer of glucose, by conceptus trophectoderm. Although glucose is an energy source for proliferation and growth of mammalian cells, the role of fructose in uterine histotroph is unclear although it is the most abundant hexose sugar in fetal blood and fluids of ungulate mammals (e.g., cows, sheep, and pigs). In this study, we used porcine trophectoderm cells to determine that fructose increased cell proliferation, as did glucose. Western blot analyses of porcine trophectoderm cell extracts revealed that fructose increased the abundance of phosphorylated-RPS6K, -EIF4EBP1, and -RPS6 over basal levels within 30 min, and those levels remained elevated to 120 min. Phosphorylation of both RPS6K and EIF4EBP1 proteins in response to fructose was inhibited by inhibitors of both PI3K and MTOR. Further, when we investigated the inhibition of glutamine-fructose-6-phosphate transaminase 1 (GFPT1) by azaserine (an inhibitor of GFPT1) and GFPT1 siRNA, we found that MTOR-RPS6K and MTOR-EIF4EBP1 signaling in response to fructose is mediated via GFPT1 activation and the hexosamine pathway. We further demonstrated that fructose stimulates the production of hyaluronic acid via GFPT1 and the hexosamine biosynthesis pathway. Collectively, these results demonstrate critical roles for fructose that are mediated via the hexosamine biosynthesis pathway to stimulate MTOR cell signaling, proliferation of porcine trophectoderm cells, and synthesis of hyaluronic acid, a significant glycosaminoglycan in the pregnant uterus.Proceedings of the National Academy of Sciences 05/2012; 109(25):E1619-28. · 9.81 Impact Factor
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ABSTRACT: Selection for hyperprolific sows, as a means of increasing litter size and profit, has resulted in an increased number of low-birthweight (LBW) piglets. These LBW piglets might suffer from increased morbidity and mortality during the early neonatal period. In addition, they show reduced growth performance, meat and carcass quality, which leads to an important economic loss for the farmer in the post-natal period. Therefore, nutritional interventions can be undertaken to prevent and rear LBW piglets. In the first part of this review, the preventive strategies at the sow level will be discussed. Approaches in preventing LBW piglets are to optimize the intrauterine environment via supplementing the sow during gestation. In the second part of this review, the interventions at the piglet level will be described. To increase the survival and growth rates of LBW piglets, one must focus on ensuring adequate colostrum and milk intake. Interventions include supplementing piglets, split nursing, split weaning and cross-fostering. Additional interventions increasing the probability of optimal post-natal food intake will be discussed.J Anim Physiol a Anim Nutr 10/2013; · 1.25 Impact Factor
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ABSTRACT: Fetal alcohol syndrome (FAS) is a significant problem in human reproductive medicine. Maternal alcohol administration alters maternal amino acid homeostasis and results in acidemia in both mother and fetus, causing fetal growth restriction. We hypothesized that administration of glutamine, which increases renal ammoniagenesis to regulate acid-base balance, may provide an intervention strategy. This hypothesis was tested using sheep as an animal model. On day 115 of gestation, ewes were anesthetized and aseptic surgery was performed to insert catheters into the fetal abdominal aorta as well as the maternal abdominal aorta and vena cava. On day 128 of gestation, ewes received intravenous administration of saline, alcohol [1.75 g/kg body weight (BW)/h], a bolus of 30 mg glutamine/kg BW, alcohol + a bolus of 30 mg glutamine/kg BW, a bolus of 100 mg glutamine/kg BW, alcohol + a bolus of 100 mg glutamine/kg BW, or received CO(2) administration to induce acidemia independent of alcohol. Blood samples were obtained simultaneously from the mother and the fetus at times 0 and 60 min (the time of peak blood alcohol concentration) of the study. Administration of alcohol to pregnant ewes led to a reduction in concentrations of glutamine and related amino acids in plasma by 21-30 %. An acute administration of glutamine to ewes, concurrent with alcohol administration, improved the profile of most amino acids (including citrulline and arginine) in maternal and fetal plasma. We suggest that glutamine may have a protective effect against alcohol-induced metabolic disorders and FAS in the ovine model.Amino Acids 01/2013; · 3.91 Impact Factor