Dietary requirements of synthesizable amino acids by animals: a paradigm shift in protein nutrition

Amino acids are building blocks for proteins in all animals. Based on growth or nitrogen balance, amino acids were traditionally classified as nutritionally essential or nonessential for mammals, birds and fish. It was assumed that all the “nutritionally nonessential amino acids (NEAA)” were synthesized sufficiently in the body to meet the needs for maximal growth and optimal health. However, careful analysis of the scientific literature reveals that over the past century there has not been compelling experimental evidence to support this assumption. NEAA (e.g., glutamine, glutamate, proline, glycine and arginine) play important roles in regulating gene expression, cell signaling, antioxidative responses, fertility, neurotransmission, and immunity. Additionally, glutamate, glutamine and aspartate are major metabolic fuels for the small intestine to maintain its digestive function and to protect the integrity of the intestinal mucosa. Thus, diets for animals must contain all NEAA to optimize their survival, growth, development, reproduction, and health. Furthermore, NEAA should be taken into consideration in revising the “ideal protein” concept that is currently used to formulate swine and poultry diets. Adequate provision of all amino acids (including NEAA) in diets enhances the efficiency of animal production. In this regard, amino acids should not be classified as nutritionally essential or nonessential in animal or human nutrition. The new Texas A&M University’s optimal ratios of dietary amino acids for swine and chickens are expected to beneficially reduce dietary protein content and improve the efficiency of their nutrient utilization, growth, and production performance

Uterine glands impact uterine receptivity, luminal fluid homeostasis and blastocyst implantation

Uterine glands are essential for pregnancy in mice and likely humans, because they secrete or transport bioactive substances that regulate uterine receptivity for blastocyst implantation. In mice, the uterus becomes receptive to blastocyst implantation on day 4, but is refractory by day 5. Here, blastocysts could be recovered from progesterone-induced uterine gland (PUGKO) but not wildtype (WT) mice on day 5 post-mating. Anti-adhesive Muc1 protein and microvilli were present on the luminal epithelium of PUGKO but not WT uteri. A number of known uterine receptivity genes and gland-specific genes were altered in the PUGKO uterus. Next, the uterus and uterine luminal fluid (ULF) were obtained from WT and PUGKO mice on day 3, 4 and 5. Transcriptome analysis revealed that 580 genes were decreased in the PUGKO uterus, however ULF secrotome analysis revealed that many proteins and several amino acids were increased in the PUGKO ULF. Of note, many proteins encoded by many gland-specific genes were not identified in the ULF of WT mice. These results support the ideas that uterine glands secrete factors that regulate ULF homeostasis and interact with other cell types in the uterus to influence uterine receptivity and blastocyst implantation for the establishment of pregnancy

Functional roles of fructose

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

Utilization Juice Wastes as Corn Replacement in the Broiler Diet

An experiment was conducted with 80 unsexed broilers of the Arbor Acress strain to determine the capability of a carrot and fruit juice wastes mixture (carrot, apple, manggo, avocado, orange, melon and Dutch egg plant) in the same proportion for replacing corn in broiler diet. This study involved a completely randomized design (CRD) with 5 treatments (0, 5, 10, 15, and 20% of juice wastes mixture in diets) and 4 replicates per treatment. Diets were isonitrogenous (22% crude protein) and isocaloric (3000 kcal/kg diet). Measured variables were feed consumption, average daily gain, feed conversion, as well as percentages of abdominal fat pad, carcass, digestive organs (liver, pancreas and gizzard), and heart. Data were analyzed by analysis of variance for CRD. Increasing juice wastes mixture levels in diets increased feed consumption (P0.05) on carcass, liver, pancreas, gizzard or heart percentages. In conclusion, up to 20% of juice wastes mixture could be included for the broiler diet to effectively replace up to 40% corn in the diet

The relevance of functional amino acids to support the health of growing pigs

On commercial farms, young growing pigs are frequently affected by health problems from multifactorial origins (e.g. environmental changes, biosecurity, management, and feed) that result in inflammation and activation of body defenses. Inflammation states alter animal metabolism in such a way that nutrients (particularly amino acids) are diverted from the use for growth towards the production of defense-related proteins and low-molecular-weight compounds (e.g., nitric oxide, H2S, and glutathione) for supporting the activity of rapidly dividing cells such as immune cells and enterocytes. Furthermore, amino acids may act specifically as signaling molecules to regulate metabolic pathways during inflammation. Thus, new knowledge on the specific role and metabolism of each amino acid is needed to refine nutritional recommendations for pigs of different phenotypes and genotypes, with the objective of maintaining animal health and performance under sub-optimal rearing conditions. This paper aims at summarizing recent advances in research on the functional roles of amino acids related to swine health. Specifically, the review highlights current knowledge on the impact of inflammation on the intake and metabolism of amino acids; their relevance for the physical gut mucosal barrier and antioxidant defense, as well as their roles in the syntheses of defense molecules and in the regulation of immune response. Practical implications for feeding strategies adapted to various health conditions of growing pigs are also discussed along with our general perspectives on related research

4-Hydroxy-2-nonenal induces apoptosis by activating ERK1/2 signaling and depleting intracellular glutathione in intestinal epithelial cells

Excessive reactive oxygen species (ROS) induces oxidative damage to cellular constituents, ultimately leading to induction of apoptotic cell death and the pathogenesis of various diseases. The molecular mechanisms for the action of ROS in intestinal diseases remain poorly defined. Here, we reported that 4-hydroxy-2-nonenal (4-HNE) treatment led to capses-3-dependent apoptosis accompanied by increased intracellular ROS level and reduced glutathione concentration in intestinal epithelial cells. These effects of 4-HNE were markedly abolished by the antioxidant L-cysteine derivative N-acetylcysteine (NAC). Further studies demonstrated that the protective effect of NAC was associated with restoration of intracellular redox state by Nrf2-related regulation of expression of genes involved in intracellular glutathione (GSH) biosynthesis and inactivation of 4-HNE-induced phosphorylation of extracellular signal-regulated protein kinases (ERK1/2). The 4-HNE-induced ERK1/2 activation was mediated by repressing mitogen-activated protein kinase phosphatase-1 (MKP-1), a negative regulator of ERK1/2, through a proteasome-dependent degradation mechanism. Importantly, either overexpression of MKP-1 or NAC treatment blocked 4-HNE-induced MKP-1 degradation, thereby protecting cell from apoptosis. These novel findings provide new insights into a functional role of MKP-1 in oxidative stress-induced cell death by regulating ERK1/2 MAP kinase in intestinal epithelial cells

Improving the Nutrient Quality of Juice Waste Mixture by Steam Pressure for Poultry Diet

The problem of juice waste mixture as poultry diet was high in crude fiber and low in metabolizable energy contents. Experiments were performed to improve the nutrient quality of juice waste mixture by using steam pressure. The first experiment was designed in a completely randomized design with 4 different incubation times of juice waste mixture (0, 15, 30, and 45 minutes) in Autoclave (15 psi pressure and 121 °C), and each treatment was replicated 5 times. Measured variables were crude fiber, crude protein, crude fat. The second experiment was to compare of crude fiber, crude protein, ether extract, NDF, ADF, cellulose, hemi-cellulose, lignin, nitrogen retention, amino acid profile, and metabolizable energy of juice waste mixture between treated vs. untreated one. The results showed that the crude fiber, crude protein, and crude fat of juice waste mixture were significantly affected (P<0.05) by incubation time in autoclave. The incubation time for 30 minutes decreased crude fiber and crude fat, but increased crude protein contents of the juice waste mixture. The crude fiber, ether extract, NDF, ADF, cellulose, and lignin contents between untreated vs treated reduced from 17.10, 6.24, 34.30, 24.40, 12.20, and 11.80% to 12.02, 4.06, 32.62, 22.05, 10.50, 11.55%, respectively. Meanwhile, nitrogen retention, crude protein, hemi-cellulose, and metabolizable energy increased from 59.99, 8.40, 9.90%, and 1744 kcal/kg to 65.51, 13.35, 10.57%, and 2550 kcal/kg, respectively. In conclusion, the incubation time for 30 minutes in autoclave was the best treatment for improving the nutrient quality of juice waste mixture

Amino acids and mammary gland development: nutritional implications for milk production and neonatal growth

Milk is synthesized by mammary epithelial cells of lactating mammals. The synthetic capacity of the mammary gland depends largely on the number and efficiency of functional mammary epithelial cells. Structural development of the mammary gland occurs during fetal growth, prepubertal and post-pubertal periods, pregnancy, and lactation under the control of various hormones (particularly estrogen, growth hormone, insulin-like growth factor-I, progesterone, placental lactogen, and prolactin) in a species- and stage-dependent manner. Milk is essential for the growth, development, and health of neonates. Amino acids (AA), present in both free and peptide-bound forms, are the most abundant organic nutrients in the milk of farm animals. Uptake of AA from the arterial blood of the lactating dam is the ultimate source of proteins (primarily β-casein and α-lactalbumin) and bioactive nitrogenous metabolites in milk. Results of recent studies indicate extensive catabolism of branched-chain AA (leucine, isoleucine and valine) and arginine to synthesize glutamate, glutamine, alanine, aspartate, asparagine, proline, and polyamines. The formation of polypeptides from AA is regulated not only by hormones (e.g., prolactin, insulin and glucocorticoids) and the rate of blood flow across the lactating mammary gland, but also by concentrations of AA, lipids, glucose, vitamins and minerals in the maternal plasma, as well as the activation of the mechanistic (mammalian) target rapamycin signaling by certain AA (e.g., arginine, branched-chain AA, and glutamine). Knowledge of AA utilization (including metabolism) by mammary epithelial cells will enhance our fundamental understanding of lactation biology and has important implications for improving the efficiency of livestock production worldwide

Local Gromov-Witten Invariants are Log Invariants

We prove a simple equivalence between the virtual count of rational curves in the total space of an anti-nef line bundle and the virtual count of rational curves maximally tangent to a smooth section of the dual line bundle. We conjecture a generalization to direct sums of line bundles.Comment: 15 pages, version accepted for publication in Advances in Mathematic