Newton Makenzie G, Lopez Arianna N, Stenhouse Claire, Hissen Karina L, Connolly Erin D, Li Xingchi, Zhou Lan, Wu Guoyao, Foxworth William B, Bazer Fuller W
Department of Animal Science, Texas A&M University, College Station, Texas, 77843, USA.
Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas, 77843, USA.
J Anim Sci Biotechnol. 2025 Jan 6;16(1):5. doi: 10.1186/s40104-024-01135-z.
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. This study aimed to determine the impact of feeding L-citrulline to meat goats during gestation to improve reproductive success. Meat goats were fed either a control (CON) or L-citrulline (CIT) supplemented diet from d 12 to 82 of gestation. Blood samples were collected and sera were subjected to high-performance liquid chromatography analyses to quantify the abundance of amino acids. Pregnancy rates were determined on d 30, 61, and 90 of gestation, and litter weight, individual birth weights, and 90 d 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 d 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 d adjusted weaning weights than those born to Spanish or F1 Boer-Spanish does.
This study provides proof of concept that feeding dietary L-citrulline increases concentrations of citrulline and arginine in blood of gestating meat goats. However, further studies are needed to understand the cellular mechanisms impacted by feeding this supplement. Regardless, this study demonstrated that feeding L-citrulline has the potential to increase reproductive performance in gestating ruminants.
肉用山羊养殖是一项全球性产业，其产品包括肉、奶、肥皂和纤维。美国约有260万只肉用山羊。对于繁殖期的雌性反刍动物，妊娠早期损失估计在妊娠的第一个月内达到30%。细胞外L-瓜氨酸（L-精氨酸的前体）由于缺乏摄取而不会被瘤胃微生物降解。L-精氨酸以及L-瓜氨酸对胎盘形成以及随后的胎儿-胎盘发育和存活具有有益影响。本研究旨在确定在妊娠期给肉用山羊饲喂L-瓜氨酸对提高繁殖成功率的影响。在妊娠第12天至82天，给肉用山羊饲喂对照（CON）日粮或添加L-瓜氨酸（CIT）的日粮。采集血样，血清进行高效液相色谱分析以定量氨基酸丰度。在妊娠第30天、61天和90天测定妊娠率，并收集产仔体重、个体出生体重和90天校正断奶体重。
与CON组母羊相比，CIT组母羊的瓜氨酸、鸟氨酸和精氨酸浓度更高，但CON组和CIT组母羊的妊娠率没有差异。单胎出生的雄性羔羊出生体重比雌性羔羊大，但双胎或三胎出生的羔羊未观察到这种表型。此外，CON组母羊所生的雄性羔羊90天校正断奶体重比雌性羔羊大，但在CIT组未观察到这种情况。CON组和CIT组布尔山羊所生的雌性羔羊90天校正断奶体重比西班牙或F1布尔-西班牙杂交母羊所生的羔羊重。
本研究提供了概念验证，即饲喂日粮L-瓜氨酸可提高妊娠肉用山羊血液中瓜氨酸和精氨酸的浓度。然而，需要进一步研究以了解饲喂这种补充剂所影响的细胞机制。无论如何，本研究表明饲喂L-瓜氨酸有可能提高妊娠反刍动物的繁殖性能。
