Ability of the Chinese herbal residue to alleviate short-distance transportation stress in sheep through the remodeling of the rumen microbiome–metabolism axis

Abstract Background Transportation is a common stressor in sheep production that is capable of inducing oxidative stress and impairing sheep health and production performance. This study aimed to investigate the alleviating effects of the traditional formula Siji Antiviral Mixture residue after water extraction, which still contains active ingredients, including fiber, polyphenols, and flavonoids, on short-distance transport stress in sheep, as well as its mechanism of action in regulating oxidative stress through the rumen microbiota‒metabolism axis. Results Twenty first-lambing East Friesian × Hu sheep hybrids weighing 54.49 ± 7.94 kg were randomly assigned to a control group (CON, basal diet) or a Chinese herbal residue group (CMR, basal diet + 50 g/d CMR) feeding at 4 h after approximately 300 km of short-distance transport. Results indicated that 4 h of short-distance transport significantly elevated serum reactive oxygen species (ROS) levels in sheep. Supplementation with Chinese herbal medicine residues markedly reduced serum ROS and lactate dehydrogenase levels while increasing glutathione peroxidase and immunoglobulin G levels. Metagenomic results revealed significantly increased abundance of bacteria such as Selenomonas ruminantium in the rumen of the CMR group, along with substantial increases in CAZymes, including AA7, GH113, and GH84. Metabolomic analysis revealed differentially expressed metabolites in plasma and rumen fluid that were enriched in metabolic pathways such as glycerophospholipid metabolism, α-linolenic acid metabolism, and drug metabolism–cytochrome P450. Correlation network analysis further revealed that Selenomonas ruminantium was significantly negatively correlated with ROS and positively correlated with ruminal LysoPC (16:1(9Z)/0:0), plasma phosphatidylcholine, and key glycerophospholipid metabolism enzymes (e.g., EC 3.1.4.3, PLC). Glycerophospholipid metabolism exhibited synergistic regulatory interactions with arachidonic acid metabolism and drug metabolism–cytochrome P450 pathways. Conclusion This study confirmed that 4 h of short-distance transport can induce oxidative stress in sheep. Supplementing feed with Siji Antiviral Mixture herbal residue effectively alleviated transport stress and enhanced immune function. The mechanism of action involved rumen microbial conversion of the herbal residue, which substantially increased the abundance of Selenomonas ruminantium. Related metabolites then regulated host arachidonic acid metabolism and cytochrome P450 drug metabolism indirectly through the glycerophospholipid metabolic pathway and the rumen microbiota–metabolism axis, thereby synergistically exerting antioxidant effects.