Effect on physiological parameters and semen quality upon oral administration of fresh onion juice to V-line rabbit buck during severe heat stress

Anti-oxidant effects of herbal residue from Shengxuebao mixture on heat-stressed New Zealand rabbits

Heat stress can lead to hormonal imbalances, weakened immune system, increased metabolic pressure on the liver, and ultimately higher animal mortality rates. This not only seriously impairs the welfare status of animals, but also causes significant economic losses to the livestock industry. Due to its rich residual bioactive components and good safety characteristics, traditional Chinese medicine (TCM) residue is expected to become a high-quality feed additive with anti-oxidative stress alleviating function. This study focuses on the potential of Shengxuebao mixture herbal residue (SXBR) as an anti-heat stress feed additive. Through the UPLC (ultra performance liquid chromatography) technology, the average residue rate of main active ingredients from SXBR were found to be 25.39%. SXBR were then added into the basal diet of heat stressed New Zealand rabbits at the rates of 5% (SXBRl), 10% (SXBRm) and 20% (SXBRh). Heat stress significantly decreased the weight gain, as well as increased neck and ear temperature, drip loss in meat, inflammation and oxidative stress. Also, the hormone levels were disrupted, with a significant increase in serum levels of CA, COR and INS. After the consumption of SXBR in the basal diet for 3 weeks, the weight of New Zealand rabbits increased significantly, and the SXBRh group restored the redness value of the meat to a similar level as the control group. Furthermore, the serum levels T3 thyroid hormone in the SXBRh group and T4 thyroid hormone in the SXBRm group increased significantly, the SXBRh group showed a significant restoration in inflammation markers (IL-1β, IL-6, and TNF-α) and oxidative stress markers (total antioxidant capacity, HSP-70, MDA, and ROS) levels. Moreover, the real-time fluorescence quantitative PCR analysis found that, the expression levels of antioxidant genes such as Nrf2, HO-1, NQO1, and GPX1 were significantly upregulated in the SXBRh group, and the expression level of the Keap1 gene was significantly downregulated. Additionally, the SXBRm group showed significant upregulation in the expression levels of HO-1 and NQO1 genes. Western blot experiments further confirmed the up-regulation of Nrf2, Ho-1 and NQO1 proteins. This study provides a strategy for the utilization of SXBR and is of great significance for the green recycling of the TCM residues, improving the development of animal husbandry and animal welfare.

Effect of dietary onion (Allium cepa L.) powder as an antioxidant on semen quality, blood biochemicals, and reproductive parameters, as well as immunological variables of rabbit bucks under severe heat stress

This study aimed to evaluate the antioxidant effects of onion (Allium cepa L.) powder on the immunological variables, redox state, and semen quality of rabbit bucks exposed to severe heat stress. Thirty-six mature bucks (7 months old) were divided into three groups consisting of 12 bucks each, namely group I, control; group II, 400 mg onion powder/kg diet; and group III, 800 mg onion powder/kg diet. The quality of semen was evaluated for volume, pH, motility, concentration, total sperm output, viability, and packed sperm volume. Blood samples were collected in the 12th week for estimation of red blood cells (RBC), white blood cells (WBC), and erythrocytic indices. Serum proteins, glutamate oxaloacetate (GOT), glutamate pyruvate transaminase (GPT), urea, creatinine, testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), immunoglobulins, malondialdehyde (MDA), total antioxidant capacity (TAC), glutathione, superoxide dismutase (SOD), and catalase (CAT) were measured. The temperature-humidity index (THI) obtained was within the range of 28.85-33.08 indicating severe heat stress. The results show that mass and individual motility, concentration, total sperm output, sperm viability, and packed sperm volume were higher (P < 0.05) in groups II and group III, with group III having the highest (P < 0.05) levels compared to group I. Compared to group I, groups II and III had higher (P < 0.05) concentrations of RBC, MCV, MCH, FSH, LH, SOD, and catalase. The highest concentration (P < 0.05) of GPT was obtained in group III compared to other groups. The highest concentration of IgG (P < 0.05) was obtained in group II while the lowest was in group I. In conclusion, dietary supplementation with onion powder at 400 or 800 mg/kg diet improves semen quality, RBC, FSH, LH, SOD, catalase, and IgG while ameliorating the adverse effects of heat stress and improve the health and reproduction of rabbits.