Department of Animal and Range Sciences, Montana State University, Bozeman, Montana 59717, USA.
J Anim Sci. 2011 Dec;89(12):4305-13. doi: 10.2527/jas.2010-3391. Epub 2011 Jul 8.
Neonatal lamb mortality is a major factor affecting profitability in the sheep industry, and lamb thermogenesis is a key element in neonatal lamb survival. Increased lamb vigor has been reported when ewes were supplemented during late gestation with algae-derived docosahexaenoic acid (DHA); however, the effects of DHA on lamb thermogenesis and immunocompetence have not been investigated. Eighty twin-bearing Targhee ewes (ages 2 to 5 yr; 68.5 ± 3 kg) were assigned randomly to 1 of 2 supplement treatments to determine the effects of feeding DHA to ewes during late gestation and early lactation on lamb thermogenesis, serum metabolites and hormones, and lamb growth. Supplement treatments were 12 g·ewe(-1)·d(-1) of algae-derived DHA (DHA Gold Advanced Bionutrition Corp., Columbia, MD; algae-derived DHA); and no algae-derived DHA (control). Supplements were individually fed daily during the last 30 d (±7 d) of gestation and pen fed (6 pens/treatment with 6 or 7 ewes/pen) during the first 38 d (±7 d) of lactation. One hour after lambing and before nursing, twin-born lambs were weighed, blood sampled via jugular puncture, and placed in a dry cold chamber for 30 min (0°C), and rectal temperatures were recorded every minute for 30 min. Lambs were removed from the cold chamber, blood sampled, warmed for 15 min, and returned to their dam. Ewes were blood sampled, and colostrum samples were collected 1 h postpartum. Ewe and lamb sera were assayed for glucose, NEFA, cortisol, and leptin. Lamb rectal temperature, glucose, NEFA, cortisol, leptin, and birth weights did not differ between treatments. The BW at 38 d was greater (P = 0.03) for lambs born to control ewes than for lambs born to algae-derived DHA-supplemented ewes; however, the colostrum of algae-derived DHA-supplemented ewes had a greater specific gravity (P = 0.05) than for control ewes. Overall, despite a potentially positive effect on ewe colostral IgG concentrations, supplementation of algae-derived DHA during late gestation and early lactation had a negative effect on lamb BW and did not affect indices of lamb thermogenesis.
新生羔羊死亡率是影响绵羊养殖业盈利能力的主要因素，而羔羊体温生成是新生羔羊存活的关键因素。研究报道，在妊娠后期和哺乳期给母羊补充藻类衍生的二十二碳六烯酸（DHA）可以提高羔羊活力；然而，DHA 对羔羊体温生成和免疫功能的影响尚未得到研究。将 80 只双胎妊娠的特格（Targhee）母羊（年龄 2 至 5 岁；68.5±3kg）随机分配到 2 种补充处理中的 1 种，以确定在妊娠后期和哺乳期给母羊补充藻类衍生的 DHA 对羔羊体温生成、血清代谢物和激素以及羔羊生长的影响。补充处理为 12g·只(-1)·天(-1)藻类衍生的 DHA（DHA Gold Advanced Bionutrition Corp.，马里兰州哥伦比亚；藻类衍生的 DHA）；和不添加藻类衍生的 DHA（对照组）。在妊娠最后 30 天（±7 天）期间，每天单独给母羊喂食补充剂，在哺乳期的前 38 天（±7 天）期间，将其放入围栏中喂养（每个处理 6 个围栏，每个围栏 6 或 7 只母羊）。羔羊出生后 1 小时，在哺乳前，对双胞胎羔羊进行称重、颈静脉穿刺采血，并将其放入 30 分钟（0°C）的干燥冷室中，在 30 分钟内每 1 分钟记录直肠温度。羔羊从冷室中取出，采血，加热 15 分钟，然后返回母羊身边。采集母羊血清样本，产后 1 小时收集初乳样本。检测母羊和羔羊血清中的葡萄糖、非酯化脂肪酸（NEFA）、皮质醇和瘦素。处理之间羔羊的直肠温度、葡萄糖、NEFA、皮质醇、瘦素和初生重没有差异。与对照组相比，出生于补充藻类衍生的 DHA 的母羊的羔羊在 38 日龄时的体重更大（P=0.03）；然而，补充藻类衍生的 DHA 的母羊的初乳比重更大（P=0.05）。总体而言，尽管对母羊初乳 IgG 浓度有潜在的积极影响，但在妊娠后期和哺乳期补充藻类衍生的 DHA 对羔羊体重有负面影响，并且不影响羔羊体温生成指数。
