Complex phytonutrients (CPS) have attracted extensive interest due to their anti-inflammatory effects. This investigation focused on the impact of CPS on rumen health in lambs on high-concentrate diets, emphasizing growth performance, ruminal fermentation, epithelial barrier integrity, ruminal metabolism, and microbial communities. A total of 54 lambs, 3 months old and with a 30.42 ± 0.54 kg body weight, were randomly assigned to three treatment groups, with six replicates per treatment and three lambs per replicate. The lambs received a basal diet (the ratio of concentrate to forage was 75:25) without CPS supplementation (CON) or with the inclusion of 2.5 g/kg (CPS2.5) or 5.0 g/kg CPS (CPS5.0) for a total of 60 days. The CPS groups exhibited increased growth performance and improved rumen fermentation parameters. Mechanistically, CPS enhanced rumen epithelial barrier function, thereby lowering inflammation and inhibiting the overactivation of the JNK/p38 MAPK signaling pathway, and the effect of CPS5.0 was better than that of CPS2.5. Notably, CPS5.0 could optimize the composition of rumen microbiota and increase the levels of Ursolic acid and other metabolites. The strong associations between rumen bacteria and health-related indicators and differential metabolites were further highlighted. Our findings suggest that adding CPS to lambs’ diets has widespread positive impacts, including improved growth performance, reduced inflammation and mRNA relative expression of apoptosis-related genes, enhanced barrier function, and beneficial changes in the rumen microbiome and metabolite profiles.

Dietary regulation of intramuscular fat (IMF) deposition and fatty acid composition offers an effective strategy to enhance meat nutritional value. As phytogenic supplements rich in bioactive compounds, complex plant extracts (CPE) have demonstrated potential in improving meat quality through lipid metabolism modulation while ensuring food safety. In this study, we used 36 female sheep, approximately 4 months old and with a similar weight (29.92 ± 2.52 kg), to investigate the effects of CPE supplementation (80 mg/kg) on lipid metabolism. After the 75-day standardized feeding trial, the sheep were subjected to humane slaughter procedures and collected the Longissimus dorsi muscle (LDM) for further experimental process. The findings indicate that CPE significantly increased (p < 0.05) the IMF content (36%) and total fatty acids concentration (10,045.79 to 26,451.99 ug/g). Lipid metabolism in LDM was mainly affected by regulating phospholipids (six lipid subclasses were affected). The qRT-PCR analysis showed that differential expressed genes, PLA2G2D and PLA2G4E, associated with lipid metabolism were significantly reduced. CPE appears to modulate the fatty acids through sphingolipid, linolenic acid metabolism, and glycosphingolipid biosynthesis pathways. Thus, this study uncoded the mechanisms of CPE on fatty acid, providing critical evidence that CPE can regulate the meat quality of ruminants.

This study aimed to determine the optimal supplementation level of sodium humate (SH) for improving rumen fermentation efficiency in vitro. Using rumen fluid from four donor ewes with three experimental replicates per treatment, we evaluated a basal diet supplemented with SH at 0 (control), 0.5 (SH0.5), 1 (SH1), and 2 (SH2) g/kg dry matter. The results of this study revealed that after 12 h of incubation, compared to the control group, the SH0.5 group significantly decreased gas production (GP) by −11.66% (p < 0.01). There were no significant differences in pH values, bacterial crude protein (BCP) content, and ammonia nitrogen (NH₃-N) concentration among the groups (p > 0.05). After 24 h of incubation, no significant differences in pH values were observed among the groups (p > 0.05). The SH1 group exhibited significantly higher BCP content compared to other treatments (p < 0.05), concomitant with a marked reduction in NH₃-N concentration (p < 0.01). Compared to the control group, GP in the SH1 group increased significantly by 7.16%, and a significant increase of 5.43% (p < 0.05), while it decreased significantly by −9.96% in the SH0.5 group (p < 0.01). However, no significant differences in volatile fatty acids were observed among the groups after either 12 or 24 h of fermentation. The addition of 1 g/kg SH altered the composition of the rumen bacterial community, which was indicated by the increased relative abundances of Prevotella, Anaerovibrio, and Saccharofermentans and the decreased relative abundances of Actinobacteriota, Lachnospiraceae_NK3A20_group, and [Ruminococcus]_gauvreauii_group (p < 0.05). Furthermore, Anaerovibrio was negatively correlated with NH₃-N and positively correlated with gas production, while [Ruminococcus]_gauvreauii_group was negatively correlated with gas production. The study indicates that the addition of 1 g/kg SH optimizes rumen fermentation efficiency and improves nutrient utilization by modulating the structure and composition of the bacterial community, thus serving as an effective additive for enhancing rumen fermentation and feed utilization in ruminants.

The low production efficiency of tannase and the insufficient utilization of high-tannin feed resources form the research background and research significance of this study. In this experiment, the tannase sequence TanLpl from Lactiplantibacillus plantarum ATCC14917T (obtained from a microbial culture collection) was selected. These sequences were respectively integrated into the expression systems of Bacillus subtilis 168 (BS168) and Bacillus subtilis WB600 (WB600) through plasmids TanLpl-p43NMK and TanLpl-pHT43. This successfully constructed three tannase-producing strains: TanLpl-p43NMK-Bacillus subtilis 168 (BS168(p43NMK)), TanLpl-pHT43-Bacillus subtilis 168 (BS168(pHT43)), and TanLpl-pHT43-Bacillus subtilis WB600 (WB600(pHT43)). An evaluation of the recombinant strains’ growth characteristics, expression stability, and enzymatic properties revealed that all three strains reached the stationary phase after 18 h of growth, with no significant differences in growth rate compared to the parental strains. At the 10th generation of subculture, the plasmid loss rate of BS168(p43NMK) was significantly higher than that of BS168(pHT43) or WB600(pHT43) (p < 0.05). The optimal temperature for tannase activity in all three recombinant strains was 30 °C, with an optimal pH value of 5.0. Under these conditions, the tannase activities were 68.81 U/mL, 397.36 U/mL, and 461.12 U/mL, respectively. The recombinant strain WB600(pHT43) exhibited superior expression stability and enzyme production capability compared to the other two strains. The research on the heterologous expression of tannase and its application in feed utilization has important theoretical and practical significance: it enriches the technical system for the heterologous expression of functional enzymes in Bacillus subtilis, provides new ideas for the efficient production of industrial enzymes, and promotes the development of bio-manufacturing technology.

Fatty acid contributes notably to meat nutrition value. A previous study investigated how complex plant extracts (CPE) can improve the fatty acid composition of ruminants, but the molecular mechanism remains unknown. This study aimed to examine the effect of dietary CPE supplementation on sheep growth performance and fatty acid composition in back fat (BF), combining lipidomics and transcriptomics analyses to explain the underlying mechanisms. Thirty-six female sheep, weighing 29.92 ± 2.52 kg and of a similar age (~4 months old), were randomly assigned into two groups: one received a basal diet (CTRL group), and the other received the same diet supplemented with 80 mg/kg of CPE (CPE group) for 75 days. The results revealed that the values of carcass fat content (GR) in the CPE group were significantly increased (p = 0.008), and the composition of fatty acid was changed. Lipidomic analysis indicated that CPE modulated lipid metabolism by regulating the contents of lipid molecules such as phosphatidylcholine (PC), fatty acyls (FAs), cardiolipin (CL), and triglyceride (TAG). After the addition of CPE, the lipid metabolism of BF was regulated mainly by regulating the glycerophospholipid metabolism, TNF signaling pathway, and cytokine–cytokine receptor interaction signaling pathway. These results revealed that changes in fatty acids were affected by the added CPE and corresponding molecular changes, which may provide new insights on the molecular level for applying CPE in sheep to improve fatty acid composition.