Heat stress (HS) poses a significant stress challenge to growing lambs, impacting growth performance, health, and physiological responses. The study evaluated feeding an essential oil blend (EOB) on growth performance, physiological and blood parameters, oxidative, and immune responses. Thirty-two 3 mo old female (BW 18.6 ± 2.43 kg) crossbred (Mongolian × Thin-tailed Han F1) lambs were randomly assigned to either: (1) control (CON)—grain mix without EOB; or (2) EOB—an EOB blend supplemented at 4 g/kg grain mix. The EOB blend was comprised of 4.34% Zanthoxylum, 1% capsicum, and 1.06% cinnamon oils with 93.6% attapulgite carrier containing linalool, sabinene, limonene, capsaicin, cinnamaldehyde and eugenol. Extreme heat stress occurred for 39 out of the 45 d experiment. Feeding HS lambs EOB increased (p < 0.05) ADG (107.4 and 162.0 g/d for CON and EOB, respectively), forage intake (239.2 and 287.0 g/d), DMI (863.1 and 930.2 g/d), and feed efficiency (0.123 and 0.181 ADG, g/DMI, g) compared with lambs fed CON. Feeding EOB reduced (p < 0.01) respiration rates (RR) and rectal (RT) and skin temperatures (ST) compared to CON-fed lambs. Lambs fed EOB had a higher T-SOD activity and IgM concentration (0.05 < p < 0.10) than CON-fed lambs. Growing heat-stressed lambs fed EOB demonstrated a lower (p < 0.05) eosinophil percentage. Feeding EOB ameliorated HS conditions for growing crossbred lambs, which demonstrate improved growth performance, enhanced physiological responses, and overall health status.

Tail docking, serving as an important management intervention in animal husbandry, plays a significant role in regulating tail fat deposition and improving production performance and health status in fat-tailed sheep. This study systematically revealed the reprogramming effects of tail docking on the epigenetic landscape and transcriptome of fat-tailed sheep by integrating whole-genome bisulfite sequencing (WGBS) and RNA m6A methylated immunoprecipitation sequencing (MeRIP-seq). At the DNA level, the tail-docked group exhibited a pronounced trend of hypomethylation across multiple functional genomic regions, including promoters, exons, and introns. Differentially methylated regions (DMRs) were significantly enriched in pathways related to tissue development and stress response, such as the Hippo signaling pathway and adherens junctions. Pyrosequencing validation of the promoter region of the key gene DGAT1 further confirmed the reliability of the WGBS data. At the RNA level, RNA m6A modifications showed an overall up-regulated pattern: the tail-docked group displayed higher numbers of m6A peaks, greater total peak length, and increased genomic coverage compared to the control group, along with better overall prediction of modification sites. Genes associated with differential m6A peaks were closely related to processes such as stem cell pluripotency and cytoskeleton regulation. qPCR validation of several methylation-related enzyme genes (e.g., METTL3, FTO, YTHDF1) yielded results consistent with the sequencing trends. Through integrated analysis of DNA methylation and RNA methylation, we identified 143 genes with concurrent changes in methylation and mRNA expression, among which 41 genes were regulated by both DNA and RNA methylation. These genes were primarily enriched in the adherens junction pathway. Notably, two core genes CITED4 and ZNF644 showed significant changes across all three levels: DNA methylation, RNA methylation, and mRNA expression. This study systematically elucidates the epigenetic mechanism by which tail docking stress induces coordinated DNA hypo-methylation and RNA m6A hyper-methylation to regulate transcriptomic reprogramming in response to environmental intervention. The findings provide novel insights into the molecular basis of trait formation in livestock.

This study evaluated 30- and 60-day dietary Bacillus subtilis supplementation on rumen development and immune indices in weaned male Hu sheep. Forty-five lambs (60 ± 10 d) were randomized to a basal diet (CON) or the basal diet plus B. subtilis at 100 mg/kg (BSN) or 200 mg/kg (BSH) (n = 15). After 30 d, rumen papilla height was significantly higher in the BSN group than in the CON and BSH groups (P = 0.026); Total volatile fatty acids (TVFA) and propionate were significantly higher in the BSN and BSH groups than in the CON group (P < 0.001); Acetate/propionate was significantly lower in the BSN and BSH groups than in the CON group (P = 0.010). BSH increased the relative abundance of beneficial bacteria (including cellulolytic taxa and Lactobacillus), and serum IL-1β decreased; rumen epithelial IL-1β, CCL2, and NF-κB p65 were downregulated in BSN and BSH (P < 0.05). After 60 d, papilla height and total VFA remained higher in BSN/BSH and the acetate to propionate ratio remained lower in BSH, with sustained increases in beneficial taxa (P < 0.05). Serum IgA and IFN-γ increased and IL-1β decreased in BSN/BSH, and epithelial NF-κB p65 decreased in BSN (P < 0.05). Therefore, this study demonstrates that a 30-day supplementation of B. subtilis is effective, while for longer-term (60-day) use, a dosage of 100 mg/kg is optimal for enhancing rumen health and immune function in sheep.