Cysteine (Cys) is a semi-essential amino acid that is synthesized from methionine in mammals and affects their physiological state. This study aimed at investigating the effects of different Cys levels on the birth weight and survival rate of piglets as well as the plasma biochemical parameters, intestinal microbial diversity, and plasma metabolome of sows during late pregnancy. The results showed that 0.4% Cys supplementation increased the birth weight of piglets and decreased the calcium, triglyceride, and bilirubin levels in sows, whereas 0.5% Cys supplementation reduced the gamma-glutamyl transpeptidase levels and increased the serum glucose levels in sows at farrowing. Intestinal microbial analysis demonstrated that 0.4% Cys supplementation increased the diversity of fecal and intestinal microbiota compared with 0.5% Cys supplementation. In addition, plasma metabolomics identified 11 differential metabolites among the 0.4% Cys, 0.5% Cys, and control (basal diet) groups. The serum hypotaurine levels in sows increased by 0.4% and 0.5% Cys supplementation, and the serum acetylcysteine levels increased by 0.5% Cys supplementation; however, the differences in hypotaurine and acetylcysteine levels between the 0.4% and 0.5% Cys groups were not significant. Furthermore, Pearson analysis revealed a positive correlation between the hypotaurine levels and the abundance of Lactobacillus or Pseudobutyrivibrio and a negative correlation between the acetylcysteine levels and the abundance of Ruminococcaceae_UCG-014. Overall, the results indicated that 0.4% Cys supplementation increased the birth weight of piglets, increased the differential metabolites beneficial for combating antioxidative stress in embryos enhancing the intestinal microbial abundance in sows, and increased the diversity of fecal microbiota in sows. Thus, these findings suggest that 0.4% Cys supplementation is highly beneficial for maintaining the health of sows during late pregnancy.

中文翻译：

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从妊娠晚期到泌乳期，不同水平的半胱氨酸对母猪血浆代谢组学和肠道菌群的影响

半胱氨酸（Cys）是由蛋氨酸在哺乳动物中合成的半必需氨基酸，会影响它们的生理状态。这项研究旨在调查不同半胱氨酸水平对仔猪出生体重和存活率以及妊娠后期母猪血浆生化参数，肠道微生物多样性和血浆代谢组的影响。结果表明，0.4％Cys的添加增加了仔猪的出生体重，降低了母猪的钙，甘油三酸酯和胆红素水平，而0.5％Cys的添加降低了仔猪在分娩时的γ-谷氨酰转肽酶水平并增加了血清葡萄糖水平。肠道微生物分析表明，与添加0.5％Cys相比，添加0.4％Cys可以增加粪便和肠道菌群的多样性。此外，血浆代谢组学在0.4％Cys，0.5％Cys和对照组（基础饮食）组中鉴定出11种差异代谢产物。母猪血清次牛磺酸水平增加了0.4％和0.5％Cys，母猪血清乙酰半胱氨酸水平增加了0.5％Cys。然而，在0.4％和0.5％的Cys组之间，次牛磺酸和乙酰半胱氨酸水平的差异并不显着。此外，Pearson分析显示，低牛磺酸水平与大量牛磺酸之间存在正相关关系。在0.4％和0.5％Cys组中，牛磺酸和乙酰半胱氨酸水平的差异不显着。此外，Pearson分析显示，低牛磺酸水平与大量牛磺酸之间存在正相关关系。在0.4％和0.5％Cys组中，牛磺酸和乙酰半胱氨酸水平的差异不显着。此外，Pearson分析显示，低牛磺酸水平与大量牛磺酸之间存在正相关关系。乳杆菌或伪丁酸弧菌与乙酰半胱氨酸水平与鲁米诺球菌科_UCG-014的含量呈负相关。总体而言，结果表明0.4％的Cys补充增加了仔猪的出生体重，增加了有利于抵抗抗氧化应激的胚胎的差异代谢物，从而增强了母猪的肠道微生物含量，并增加了母猪粪便微生物群的多样性。因此，这些发现表明0.4％的Cys补充对维持妊娠后期母猪的健康非常有益。