Fincham J R, Fontenot J P, Swecker W S, Herbein J H, Neel J P S, Scaglia G, Clapham W M, Notter D R
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
J Anim Sci. 2009 Oct;87(10):3259-77. doi: 10.2527/jas.2008-1277. Epub 2009 Jul 17.
An experiment was conducted to evaluate the effects of pasture finishing versus feedlot finishing, over time, on fatty acid metabolism in Angus crossbred steers (n = 24). Ruminal fluid, serum, and adipose tissue biopsies were obtained on d 0, 28, 84, and 140. Pasture forages and diet ingredient samples were obtained at 14-d intervals to determine nutritive value and fatty acid composition. The feedlot diet consisted of corn silage, cracked corn grain, soybean meal, and a vitamin and mineral supplement. The pasture-finished steers grazed sequentially on triticale (x Triticosecale rimpaui)/annual ryegrass (Lolium multiflorum), alfalfa (Medicago sativa)/orchardgrass (Dactylis glomerata), and a cool-season grass/legume mixture. The feedlot diet contained an average of 57% of total fatty acids as linoleic acid and 2% as linolenic acid. The pasture forages contained 9% of total fatty acids as linoleic acid and 66% as linolenic acid. Concentrations (% of total fatty acids) of linolenic acid were greater (P < 0.05) in ruminal fluid, serum, and adipose tissue of the pasture-finished steers, compared with the feedlot-finished steers. Concentrations (% of total fatty acids) of cis-9, trans-11 CLA were greater (P < 0.05) in adipose tissue of the pasture-finished steers than feedlot-finished steers. Concentrations of cis-9, trans-11 CLA in adipose tissue declined (P < 0.05) in the feedlot-finished steers from d 0 to 28 to 84. In the pasture-finished steers, concentrations of cis-9, trans-11 CLA in adipose tissue (mg/g of tissue) peaked (P < 0.05) on d 28 and remained elevated (ranged from 9.91 to 12.80 mg/g of tissue) throughout the duration of the study. In the pasture-finished steers, linolenic acid concentrations tended to peak (P = 0.07) on d 28 and remained elevated (ranged from 0.64 to 0.80% of total fatty acids) throughout the study. It appears that only a short time is needed to alter the n-3 and CLA composition of adipose tissue in cattle finished on pasture.
进行了一项实验，以评估随着时间推移，牧场育肥与饲养场育肥对安格斯杂交阉牛（n = 24）脂肪酸代谢的影响。在第0、28、84和140天采集瘤胃液、血清和脂肪组织活检样本。每隔14天采集牧场草料和日粮成分样本，以测定营养价值和脂肪酸组成。饲养场日粮由玉米青贮料、破碎玉米粒、豆粕以及维生素和矿物质补充剂组成。牧场育肥的阉牛依次在小黑麦（×黑小麦）/一年生黑麦草（多花黑麦草）、苜蓿（紫花苜蓿）/果园草（鸭茅）以及冷季禾本科/豆科混合草场上放牧。饲养场日粮中总脂肪酸平均57%为亚油酸，2%为亚麻酸。牧场草料中总脂肪酸9%为亚油酸，66%为亚麻酸。与饲养场育肥的阉牛相比，牧场育肥阉牛的瘤胃液、血清和脂肪组织中亚麻酸浓度（占总脂肪酸的百分比）更高（P < 0.05）。牧场育肥阉牛脂肪组织中顺-9，反-11共轭亚油酸（CLA）浓度（占总脂肪酸的百分比）高于饲养场育肥阉牛（P < 0.05）。饲养场育肥阉牛从第0天到28天再到84天，脂肪组织中顺-9，反-11 CLA浓度下降（P < 0.05）。在牧场育肥的阉牛中，脂肪组织中顺-9，反-11 CLA浓度（mg/g组织）在第28天达到峰值（P < 0.05），并且在整个研究期间一直保持在较高水平（范围为9.91至12.80 mg/g组织）。在牧场育肥的阉牛中，亚麻酸浓度在第28天趋于达到峰值（P = 0.07），并且在整个研究期间一直保持在较高水平（范围为总脂肪酸的0.64%至0.80%）。看来，对于在牧场育肥的牛，只需较短时间就能改变其脂肪组织中n-3脂肪酸和CLA的组成。
