Encinias H B, Lardy G P, Encinias A M, Bauer M L
Department of Animal and Range Sciences, North Dakota State University, Fargo 58105, USA.
J Anim Sci. 2004 Dec;82(12):3654-61. doi: 10.2527/2004.82123654x.
Objectives of this study were to determine whether feeding high-linoleic safflower seed to gestating ewes increases cold tolerance and survival in lambs, and whether brown adipose tissue (BAT) stores in lambs are affected by prepartum safflower seed supplementation. In Trial 1, 234 gestating ewes (122 in yr 1 and 112 in yr 2; 75.5 and 81.2 +/- 0.6 kg initial BW for yr 1 and 2, respectively) were allotted randomly to one of two dietary treatments (four pens*treatment(-1)*yr(-1)). Ewes were fed alfalfa-based diets containing (DM basis) either 2.8 (LF) or 5.7% (HF) dietary fat beginning 55 (yr 1) and 42 (yr 2) +/- 1 d prepartum. In Trial 2, 40 Rambouillet cross ewes gestating twins (82.9 +/- 1.7 kg BW) were used in 2 yr (20/yr) and were fed diets containing (DM basis) either 1.9 (LF) or 4.9% (HF) dietary fat beginning 53.4 +/- 1.4 d prepartum. The basal diet was 37.5% each of grass and alfalfa hays and 25% corn silage (DM basis). Cracked safflower seeds (18% CP, 32% fat, 25.6% linoleic acid; DM basis) were used as the supplement in HF, whereas safflower meal and corn were used as the supplement in LF for both trials. At parturition, one lamb from each ewe was selected randomly for slaughter. Perirenal (PR) and pericardial (PC) BAT was excised and weighed, and the carcass was frozen for compositional analysis. In Trial 1, more lambs from HF 0.03; 15.4 vs. 5.8 +/- 2.8%), and dams survived (P = 0.03; 88.4 vs. 78.3 +/- 2.9%), fewer died due to starvation (P = there was a tendency for fewer to die due to pneumonia (P = 0.07; 0.0 vs. 1.7 +/- 0.6%). Ewes fed HF tended to wean more lambs per ewe (P = 0.09; 1.4 vs. 1.2 +/- 0.06) but had similar lamb weight weaned per ewe (P = 0.51; 23.1 +/- 1.22 kg). In Trial 2, prepartum ewe plasma NEFA and glucose concentrations increased with advancing gestation (P < 0.001). Lamb rectal temperature tended (P = 0.08) to be higher in LF lambs and tended (P = 0.06) to increase following parturition. Perirenal BAT weight did not differ among treatments (33.01 +/- 1.66 g; P = 0.28; 0.62 +/- 0.30% BW; P = 0.60). Lambs from LF dams tended (P = 0.08) to have greater PC BAT weight; however, the effect was not significant when expressed as a percentage of BW (0.13 +/- 0.007; P = 0.98). High-linoleic safflower seeds fed during the last 45 d of gestation may be beneficial in improving lamb survivability. Our data do not indicate this response was a result of increased BAT stores. More research is necessary to determine mechanisms that enhance lamb survival when high-linoleic saf-flower seed is fed during gestation.
本研究的目的是确定给妊娠母羊饲喂高亚油酸红花籽是否能提高羔羊的耐寒性和存活率，以及产前补充红花籽是否会影响羔羊的棕色脂肪组织（BAT）储备。在试验1中，234只妊娠母羊（第1年122只，第2年112只；第1年和第2年初始体重分别为75.5和81.2±0.6千克）被随机分配到两种日粮处理之一（每年4个栏处理⁻¹年⁻¹）。从产前55天（第1年）和42天（第2年）±1天开始，母羊被饲喂以苜蓿为基础的日粮，日粮脂肪含量（干物质基础）分别为2.8%（低脂肪，LF）或5.7%（高脂肪，HF）。在试验2中，40只怀有双胞胎的兰布耶杂交妊娠母羊（体重82.9±1.7千克）在2年中使用（每年20只），从产前53.4±1.4天开始被饲喂日粮脂肪含量（干物质基础）分别为1.9%（LF）或4.9%（HF）的日粮。基础日粮为干草和苜蓿干草各37.5%以及玉米青贮25%（干物质基础）。在HF组中，破碎的红花籽（粗蛋白18%，脂肪32%，亚油酸25.6%；干物质基础）用作补充料，而在两个试验的LF组中，红花籽粕和玉米用作补充料。分娩时，从每只母羊中随机选择一只羔羊进行屠宰。切除肾周（PR）和心包（PC）BAT并称重，将胴体冷冻用于成分分析。在试验1中，HF组的羔羊死亡较少（P = 0.03；15.4对5.8±2.8%），母羊存活较多（P = 0.03；88.4对78.3±2.9%），因饥饿死亡的较少（P = 0.,03），因肺炎死亡的也有减少趋势（P = 0.07；0.0对1.7±0.6%）。饲喂HF的母羊每只母羊断奶的羔羊数量有增加趋势（P = 0.09；1.4对1.2±0.06），但每只母羊断奶羔羊的体重相似（P = 0.51；23.1±1.22千克）。在试验2中，产前母羊血浆非酯化脂肪酸（NEFA）和葡萄糖浓度随妊娠进展而增加（P < 0.001）。LF组羔羊的直肠温度有升高趋势（P = 0.08），且产后有升高趋势（P = 0.06）。各处理间肾周BAT重量无差异（33.01±1.66克；P = 0.28；占体重的0.62±0.30%；P = 0.60）。来自LF组母羊的羔羊PC BAT重量有增加趋势（P = 0.08）；然而，以体重百分比表示时，该效应不显著（0.13±0.007；P = 0.98）。在妊娠最后45天饲喂高亚油酸红花籽可能有利于提高羔羊的存活率。我们的数据并未表明这种反应是BAT储备增加的结果。需要更多研究来确定在妊娠期间饲喂高亚油酸红花籽时提高羔羊存活率的机制。
