Physio-metabolic response, immune function, epigenetic markers, and reproductive performance of rabbits under environmental stress: the mitigating role of boswellia essential oil nanoemulsion

Global warming poses a significant threat to reproductive health of rabbits. Sustainable nutritional strategies are crucial for ensuring rabbit production and maintaining food security under these challenging conditions. This study sought to assess the protective benefits of dietary boswellia essential oil nano-emulsion (BEON) against oxidative stress, immune dysregulation, ferroptosis, and organ damage in female rabbits exposed to severe thermal stress. A total of 120 female rabbits were divided into four groups of 30 rabbits each. The rabbits were fed a basal diet supplemented with 0 (BEON0), 0.25 (BEON0.25), 0.5 (BEON0.5), and 1.0 (BEON1.0) mL of BEON per kilogram of diet. Results demonstrated that the BEON1.0 group exhibited significantly higher levels of IgG, superoxide dismutase (SOD), and glutathione peroxidase (GPx), while the BEON0.25 group showed elevated levels of IgM, catalase, and total antioxidant capacity (TAC) (P < 0.05). All BEON treatments significantly reduced malondialdehyde (MDA) levels (P < 0.01). Serum levels of progesterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were significantly elevated in the BEON0.5 and BEON1.0 groups compared to the control group (P < 0.01). A significant decrease in adipokine levels was observed in all BEON-supplemented groups compared to the control group (P < 0.05). All BEON groups demonstrated a modulation of ferroptosis pathways, characterized by decreased heat shock protein 70 (HSP70) expression and upregulated expression of glutathione peroxidase 4 (GPX4) and cystine transporter solute carrier 7A11 (SLC7A11) in ovarian tissues (P < 0.01). Furthermore, DNA methyltransferase 1 (DNMT1) expression increased in a dose-dependent manner with increasing BEON supplementation. Histological analysis revealed an improvement in the architecture of the liver, uterine horns, and ovarian tissues in rabbits fed BEON. Integrating BEON at doses of 0.5-1.0 mL/kg diet significantly improved reproductive performance in stressed female rabbits. PCA and correlation analyses demonstrated a positive correlation between BEON supplementation and immune function, reproductive hormone levels, and antioxidant status, while a negative correlation was observed with MDA and adipokine concentrations in rabbit serum. In conclusion, BEON supplementation demonstrates promise as a sustainable nutritional strategy for the rabbit industry, particularly in mitigating the challenges posed by global warming.