Dietary supplementation with 0.4%L-arginine between days 14 and 30 of gestation enhances NO and polyamine syntheses and water transport in porcine placentae

Background:Most embryonic loss in pigs occurs before d 30 of gestation.Dietary supplementation with L-arginine(Arg) during early gestation can enhance the survival and development of conceptuses(embryo/fetus and its extraembryonic membranes) in gilts.However,the underlying mechanisms remain largely unknown.Methods:Between d 14 and 30 of gestation,each gilt was fed daily 2 kg of a corn-and soybean-meal based diet(12% crude protein) supplemented with either 0.4% Arg(as Arg-HCl) or an isonitrogenous amount of L-alanine(Control).There were 10 gilts per treatment group.On d 30 of gestation,gilts were fed either Arg-HCl or L-alanine 30 min before they were hysterectomized,followed by the collection of placentae,embryos,fetal membranes,and fetal fluids.Amniotic and allantoic fluids were analyzed for nitrite and nitrate [NOx;stable oxidation products of nitric oxide(NO)],polyamines,and amino acids.Placentae were analyzed for syntheses of NO and polyamines,water and amino acid transport,concentrations of amino acid-related metabolites,and the expression of angiogenic factors and aquaporins(AQPs).Results:Compared to the control group,Arg supplementation increased(P < 0.05) the number of viable fetuses by 1.9 per litter,the number and diameter of placental blood vessels(+ 25.9% and + 17.0% respectively),embryonic survival(+ 18.5%),total placental weight(+ 36.5%),the total weight of viable fetuses(+ 33.5%),fetal crown-to-rump length(+ 4.7%),and total allantoic and amniotic fluid volumes(+ 44.6% and + 75.5% respectively).Compared to control gilts,Arg supplementation increased(P < 0.05) placental activities of GTP cyclohydrolase-1(+ 33.1%) and ornithine decarboxylase(+ 29.3%);placental syntheses of NO(+ 26.2%) and polyamines(+ 28.9%);placental concentrations of NOx(+ 22.5%),tetrahydrobiopterin(+ 21.1%),polyamines(+ 20.4%),c AMP(+ 27.7%),and c GMP(+ 24.7%);total amounts of NOx(+ 61.7% to + 96.8%),polyamines(+ 60.7% to + 88.7%),amino acids(+ 39% to + 118%),glucose(+ 60.5% to + 62.6%),and fructose(+ 41.4% to + 57.0%) in fetal fluids;and the placental transport of water(+ 33.9%),Arg(+ 78.4%),glutamine(+ 89.9%),and glycine(+ 89.6%).Furthermore,Arg supplementation increased(P < 0.05) placental m RNA levels for angiogenic factors [VEGFA120(+ 117%),VEGFR1(+ 445%),VEGFR2(+ 373%),PGF(+ 197%),and GCH1(+ 126%)] and AQPs [AQP1(+ 280%),AQP3(+ 137%),AQP5(+ 172%),AQP8(+ 165%),and AQP9(+ 127%)].Conclusion:Supplementing 0.4% Arg to a conventional diet for gilts between d 14 and d 30 of gestation enhanced placental NO and polyamine syntheses,angiogenesis,and water and amino acid transport to improve conceptus development and survival.

Effects of magnesium on the performance of sows and their piglets

The objective of this study was to evaluate the effects of supplemental magnesium （Mg） on the performance of gilts and parity 3 sows and their piglets. Fifty-six grits （Trial 1） and 56 sows （Trial 2） were assigned to one of 4 treatments according to their mating weight, respectively. The treatments comprised corn-soybean meal based gestation and lactation diets （0.21% magnesium） supplemented with 0, 0.015, 0.03, or 0.045% Mg from mating until weaning. The results showed that magnesium supplementation significantly （P 〈 0.05） reduced the weaning to estrus interval in both gilts and sows. There were significant effects （P 〈 0.05） of supplemental magnesium on the total number of piglets born, born alive and weaned in sows. In late gestation and lactation, the digestibility of crude fiber （quadratic effects, P 〈 0.05）, and crude protein （P 〈 0.05）, were significantly influenced by magnesium in gilts and sows, respectively. There were differences among the 4 groups in terms of the apparent digestibility of dry matter and crude fiber in sows （P 〈 0.0S） during both early and late gestation. The apparent digestibility of gross energy was increased for sows in late gestation （P 〈 0.05）, and lactation （quadratic effects, P 〈 0.0S）. At farrowing and weaning, serum prolactin levels and alkaline phosphate activities linearly increased in sows as the Mg supplementation increased （P 〈 0.0.5）. Serum Mg of sows at farrowing and serum urea nitrogen of sows at weaning was significantly influenced by Mg supplementation （P 〈 0.05）. The Mg concentration in sow colostrum and the serum of their piglets were increased by supplemental magnesium （P 〈 0.05）. In addition, growth hormone levels were linearly elevated （P 〈 0.05） in the serum of piglets suckling sows. Our data demonstrated that supplemental magnesium has the potential to improve the reproduction performance of sows, and the suitable supplemental dose ranged from 0.015% to 0.03%.