Anthelmintic treatment is widely used in equine health management to control parasitic infections; however, its potential effects on the gut microbiota and metabolic characteristics remain poorly understood. In this study, twelve Yili horses were randomly assigned to two groups: a control group (C), which received no anthelmintic treatment, and a Miechongshu-treated group (T), which was orally administered Miechongshu at a dose of 0.36 g/kg body weight on day 0. Fecal samples were collected from the rectums of Yili horses on day 14 after administration, and differences in gut microbial composition and metabolic characteristics between the two groups were further examined using 16S rRNA gene sequencing in combination with LC–MS/MS-based metabolomic analysis. The results showed that there was no significant difference in α diversity (p > 0.05). At the phylum level, compared with Group C, the relative abundance of Halobacterota significantly increased (p < 0.05). At the family level, the relative abundance of Prevotellaceae in Group T was significantly higher than that in Group C, while the relative abundance of Christensenellaceae decreased (p < 0.05). At the genus level, the relative abundance of Christensenellaceae_R-7_group was significantly decreased (p < 0.05). A total of 98 differentially expressed metabolites were identified in the total ion mode. Among them, 64 were upregulated compared with Group C, and 34 were downregulated. KEGG analysis revealed that four enriched metabolic pathways showed significant differences. Metabolic pathways, tryptophan metabolism, purine metabolism, fatty acid biosynthesis and carotenoid biosynthesis differed between the two groups. Compared with Group C, the contents of the metabolites tetradecanoic acid and adenosine were significantly decreased, while tryptophol was significantly increased. These results indicate that anthelmintic treatment is associated with alterations in the intestinal microecological balance and metabolic homeostasis of the host, providing new insights for evaluating the use of anthelmintics and the management of intestinal health in horses.

This experiment aimed to study the effects of thymol on the growth performance, blood biochemical indices, hormone levels, rumen fermentation parameters, and rumen microbial changes of Texel-Hazak sheep ewes. Thirty healthy young hybrid ewes were selected and randomly divided into two groups, 15 each: a control group (CG) and an experimental group (EG). Under the same feeding management conditions, the diet of the CG group was not treated in any way, while the basal diet of the EG group was supplemented with 30 mg/kg of thymol. The experiment lasted 72 days, including a 12-day adaptation phase and a 60-day formal feeding period. During the formal feeding period, each ewe was offered 2 kg of diet per day on an as-fed basis. The thymol dose for the EG was calculated based on this planned daily feed allowance and was thoroughly mixed into the concentrate portion, which was completely consumed during individual feeding. The results showed that adding 30 mg/kg thymol to the diet significantly increased total weight gain and average daily gain in ewes (p < 0.01), and significantly decreased the feed-to-gain ratio (p < 0.01). It also significantly increased plasma P4 levels (p < 0.05) and significantly decreased B levels (p < 0.01). Meanwhile, the 16S rRNA sequencing results further confirmed that thymol altered ruminal microbial diversity and the relative abundance of specific bacterial taxa. These results suggest that the addition of 30 mg/kg thymol to the diet may act as a nutritional regulator, providing important insights into improving physiological status and rumen health during the growth stage of Texel-Hazak replacement ewes.

This study aimed to investigate the effects of thymol supplementation in health care sand on growth performance, serum biochemical parameters, fecal microbial diversity, and fecal metabolites in Grey King squabs. A total of 160 healthy 28-day-old Grey King squabs were selected and randomly assigned to four treatment groups: the CON, 2%Thy, 3%Thy, and 4%Thy groups. Each group consisted of 10 replicates with four squabs per replicate, resulting in a total of 40 squabs per group. Under identical feeding management conditions and dietary nutrient levels, squabs in the CON group received the basal diet plus 5 g of health care sand; those in the 2%Thy group received the basal diet plus 5 g of health care sand containing 2% thymol; those in the 3%Thy group received the basal diet plus 5 g of health care sand containing 3% thymol; and those in the 4%Thy group received the basal diet plus 5 g of health care sand containing 4% thymol. The experiment lasted for 30 days. During the experimental period, the pigeons were housed in cages measuring 45 cm × 50 cm × 60 cm. Each pigeon was provided with 40 g of diet and 5 g of health care sand daily and had free access to water. After Benjamini–Hochberg false discovery rate correction, no significant differences were observed in growth performance, body measurements, apparent nutrient retention, or energy metabolizability among treatments (q > 0.05). However, thymol-supplemented groups exhibited significantly increased serum total antioxidant capacity and superoxide dismutase, glutathione peroxidase, and catalase activities, together with decreased malondialdehyde levels (q < 0.05). Fecal microbiome and metabolomic analyses were restricted to the CON and 3%Thy groups, with the 3%Thy group selected after evaluation of the phenotypic and physiological responses rather than being prespecified before the experiment. These omics comparisons were therefore considered exploratory. No statistically significant difference in overall fecal microbial community composition was detected between the two groups, whereas 17 candidate differential fecal metabolite features were observed. These features were mainly putatively annotated as lipids and lipid-like molecules, organic acids and derivatives, organoheterocyclic compounds, and benzenoids. Among the supplementation levels evaluated, the 3%Thy group showed comparatively favorable numerical responses in several measured parameters and may be considered a candidate level for further investigation. However, the present findings do not establish an optimal thymol supplementation level, and the biological significance of the exploratory fecal omics results requires further validation.