Department of Medical Analysis, Princess Aisha Bint Al-Hussein College of Nursing and Medical Sciences, Al-Hussein Bin Talal University, Ma'an, Jordan.
Biological Sciences Department, College of Science & Arts, King Abdulaziz University, Rabigh 21911, Saudi Arabia.
Res Vet Sci. 2023 Feb;155:36-43. doi: 10.1016/j.rvsc.2023.01.002. Epub 2023 Jan 5.
Heat stress (HS) is one of the most severe hurdles impacting rabbit growth, immunity, homeostasis, and productivity. Alginate oligosaccharides (AOS) have considerable beneficial effects due to their plausible antioxidant and immune-stimulatory properties. This work was planned to explore the preventive function of AOS as a new bio-feed additive against the harmful effects caused by environmental HS on growing rabbits. Rabbits were allotted in four experimental groups (25 animals in each group) and fed on a basal diet supplemented with 0.0 (AOS0), 50 (AOS50), 100 (AOS100), and 150 (AOS150) mg AOS/kg diet reared under summer conditions. Dietary AOS supplementation improved significantly (P ≤ 0.001) feed conversion rate, while both AOS100 and AOS150 significantly (P ≤ 0.001) enhanced the final body weight and body weight gain. All AOS addition significantly increased nitric oxide and lysosome activity and significantly reduced interferon-gamma (IFNγ) compared with those in the control group. Tumor necrosis factor α (TNFα), interleukin1β (IL-1β), myeloperoxidase and protein carbonyl levels were significantly reduced in rabbits fed diets containing AOS (100 and 150 mg/kg) compared with those in the control group under heat stress conditions. In addition, glutathione (GSH) and catalase (CAT) were significantly (P ≤ 0.001) improved with increasing AOS dietary levels compared with the control group. Still, total antioxidant capacity (TAC), malondialdehyde (MDA), hematocrit, mean corpuscular volume (MCV), eosinophils, and lymphocytes did not change. Erythrocyte's indices improved significantly (P ≤ 0.001), while neutrophils and white blood cell counts were decreased by dietary AOS inclusion. Immunological (IgM and IgG) were markedly reduced in AOS-treated groups compared with the control group. The current investigation exemplified that AOS as a novel bio-feed additive that could be an effective strategy to extenuate prejudicial effects in heat-stressed rabbits via enhancing immunity, and antioxidant defence system, further regulating the inflammation cytokines.
热应激（HS）是影响兔子生长、免疫、体内平衡和生产力的最严重障碍之一。由于其合理的抗氧化和免疫刺激特性，海藻酸钠寡糖（AOS）具有相当大的有益作用。本研究旨在探索 AOS 作为一种新型生物饲料添加剂的预防功能，以防止环境 HS 对生长兔造成的有害影响。将兔子分为四组（每组 25 只），在夏季条件下，分别用基础日粮添加 0.0（AOS0）、50（AOS50）、100（AOS100）和 150（AOS150）mg AOS/kg 日粮饲养。日粮 AOS 补充显著提高（P≤0.001）了饲料转化率，而 AOS100 和 AOS150 显著提高（P≤0.001）了最终体重和体重增重。与对照组相比，所有 AOS 添加均显著增加了一氧化氮和溶酶体活性，并显著降低了干扰素-γ（IFNγ）。与对照组相比，在热应激条件下，添加 AOS（100 和 150mg/kg）的日粮可显著降低肿瘤坏死因子-α（TNFα）、白细胞介素 1β（IL-1β）、髓过氧化物酶和蛋白质羰基水平。此外，与对照组相比，随着 AOS 日粮水平的增加，谷胱甘肽（GSH）和过氧化氢酶（CAT）显著提高（P≤0.001）。然而，总抗氧化能力（TAC）、丙二醛（MDA）、红细胞压积、平均红细胞体积（MCV）、嗜酸性粒细胞和淋巴细胞没有变化。红细胞指数显著提高（P≤0.001），而中性粒细胞和白细胞计数因日粮中添加 AOS 而减少。与对照组相比，AOS 处理组的免疫球蛋白（IgM 和 IgG）明显降低。本研究表明，AOS 作为一种新型生物饲料添加剂，可以通过增强免疫力和抗氧化防御系统来减轻热应激兔子的不利影响，进一步调节炎症细胞因子，是一种有效的策略。
