Impact of Dietary Supplementation of L-Citrulline to Meat Goats During Gestation on Reproductive Performance

抄録

Abstract
Background Meat goat production is a worldwide industry with products such as meat, milk, soap, and fiber being produced. There are approximately 2.6 million meat goats in the United States. For breeding female ruminants, early pregnancy loss is estimated to be 30% within the first month of gestation. Extracellular L-citrulline (a precursor to L-arginine) is not degraded by ruminal microbes due to the lack of uptake. L-arginine and thus L-citrulline, have beneficial impacts on placentation and, subsequently, fetal-placental development and survival. Results Meat goats were fed either a control (CON) or L-citrulline (CIT) supplemented diet from Days 12 to 82 of gestation. Blood samples were collected and subjected to high performance liquid chromatography analyses to quantify the abundance of amino acids. Pregnancy rates were determined on Days 30, 61, and 90 of gestation, and litter weight, individual birth weights, and 90-day adjusted weaning weights were collected. The concentrations of citrulline, ornithine, and arginine were greater in CIT does compared to CON does, but there was no difference in pregnancy rates between CON and CIT does. Birth weight was greater for male kids born as singles when compared to females, but this phenotype was not observed for kids born as twins or triplets. Further, males born to CON does had greater 90-day adjusted weaning weights than females, but this was not observed in the CIT group. Female kids born to CON and CIT Boer goats had heavier 90-day adjusted weaning weights than those born to Spanish or F1 Boer-Spanish does. Conclusion L-citrulline increased and stabilized circulating concentrations of arginine in maternal serum of meat goats. Further, L-citrulline supplementation may benefit does gestating triplets and increase 90-day adjusted weaning weights of female offspring. Boer goats may also be more sensitive to dietary supplementation with L-citrulline when compared to Spanish goats.