Saker K E, Fike J H, Veit H, Ward D L
Department of Large Animal Clinical Sciences, VA-MD Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061, USA.
J Anim Physiol Anim Nutr (Berl). 2004 Apr;88(3-4):122-30. doi: 10.1111/j.1439-0396.2003.00468.x.
Twenty-seven wether lambs were utilized to evaluate select innate immunity and oxidative stress in response to diet and heat stress. Dietary treatments were: (i) control (tall fescue) hay = no Tasco (tradename for the extract of the brown seaweed, Ascophyllum nodosum, Acadian Sealants Ltd, Nova Scotia, Canada); (ii) pre-harvest Tasco-Forage-treated hay and (iii) control hay + post-harvest Tasco-EX. Tasco-Forage and Tasco-EX are two forms of the Tasco extract that are either applied to foliage or used for direct feeding, respectively. All lambs were supplemented with soyabean meal and trace mineralized salt. Heat stress was applied for 10 days with measurements obtained at days 0, 4 and 10. A heat x treatment interaction indicated hay with Tasco enhanced monocyte oxidative burst through short duration (p < 0.05) and long duration (p < 0.10) heat stress. Phagocytic activity was influenced by days of heat stress (p < 0.001) and treatment (p = 0.02) with post-harvest Tasco lambs exhibiting the greatest immune enhancement (p < 0.05). Red and white blood cell glutathione peroxidase increased by heat stress day 10 in Tasco lambs. Superoxide dismutase activity was increased and lipid hydroperoxide metabolites minimized (p < 0.01) through long duration heat stress in the pre-harvest Tasco group. Tasco treatment of tall fescue hay prior to harvest appears to provide residual effects on animal antioxidant availability in short-duration heat stress. Tasco supplementation to post-harvest fescue hay enhances immune function and protects against prolonged heat-induced oxidative stress.
选用27只去势公羔羊来评估日粮和热应激对特定先天免疫和氧化应激的影响。日粮处理方式如下：(i) 对照（高羊茅）干草 = 不添加Tasco（棕色海藻泡叶藻提取物的商品名，加拿大新斯科舍省阿卡迪亚密封剂有限公司生产）；(ii) 收获前经Tasco-Forage处理的干草；(iii) 对照干草 + 收获后添加Tasco-EX。Tasco-Forage和Tasco-EX是Tasco提取物的两种形式，分别应用于植物叶片或直接用于饲喂。所有羔羊均补充豆粕和微量矿盐。热应激持续10天，在第0、4和10天进行测量。热应激×处理的交互作用表明，添加Tasco的干草在短期（p < 0.05）和长期（p < 0.10）热应激下均能增强单核细胞氧化爆发。吞噬活性受热应激天数（p < 0.001）和处理方式（p = 0.02）影响，收获后添加Tasco的羔羊表现出最大的免疫增强效果（p < 0.05）。在热应激第10天时，Tasco组羔羊的红细胞和白细胞谷胱甘肽过氧化物酶增加。通过长期热应激，收获前添加Tasco组的超氧化物歧化酶活性增加，脂质氢过氧化物代谢产物减少（p < 0.01）。收获前对高羊茅干草进行Tasco处理似乎在短期热应激下对动物抗氧化剂供应有残留影响。收获后对羊茅干草补充Tasco可增强免疫功能并抵御长期热诱导的氧化应激。
