Faucitano L, Chouinard P Y, Fortin J, Mandell I B, Lafrenière C, Girard C L, Berthiaume R
Agriculture & Agri-Food Canada, Sherbrooke, Québec, J1M 1Z3, Canada.
J Anim Sci. 2008 Jul;86(7):1678-89. doi: 10.2527/jas.2007-0756. Epub 2008 Mar 28.
Five beef cattle management regimens were evaluated for their effect on meat quality, fatty acid composition, and overall palatability of the longis-simus dorsi (LD) muscle in Angus cross steers. A 98-d growing phase was conducted using grass silage with or without supplementation of growth promotants (Revalor G and Rumensin) or soybean meal. Dietary treatments in the finishing phase were developed with or without supplementation of growth promotants based on exclusive feeding of forages with no grain supplementation, or the feeding of grain:forage (70:30) diets. Growth promotants increased (P < 0.01) shear force and tended (P = 0.06) to increase toughness of the LD muscle due to limited postmortem proteolytic activity (lower myofibrillar fragmentation index value; P = 0.02). Grain feeding increased DM and intramuscular fat content (P = 0.03 and P = 0.05, respectively) in the LD but decreased the sensory panel tenderness score (P = 0.01). Growth promotants increased (P </= 0.05) the proportion of C18:0, C20:0, trans isomers of C18:1, and cis-9, trans-11 C18:2. Exclusive feeding of forages increased the proportion of cis-9, cis-12, cis-15 C18:3 as well as several other isomers of the n-3 family and decreased in the ratio of n-6 to n-3 fatty acids in the LD muscle as compared with supplementing grain (P < 0.05). In addition, the forage-based diet increased (P < 0.01) the concentration in the intramuscular fat of several intermediates (cis-9, trans-11, cis-15 C18:3; trans-11, cis-15 C18:2; trans-11 C18:1) of ruminal biohydrogenation. Forage feeding also increased the proportion of cis-9, trans-11 C18:2 (P < 0.01) and decreased the concentration of trans-10 C18:1 in the LD muscle (P = 0.03). It is concluded that quality demands of health-conscious consumers can be met through a forage-finishing and growth promotants-free beef production system.
对五种肉牛饲养管理方案进行了评估，以研究其对安格斯杂交阉牛背最长肌（LD）肉质、脂肪酸组成及总体适口性的影响。在98天的生长阶段，使用了添加或不添加生长促进剂（瑞肥G和瘤胃素）或豆粕的青贮牧草。育肥阶段的日粮处理方案是，基于仅饲喂牧草不添加谷物，或饲喂谷物：牧草比例为70:30的日粮，分别添加或不添加生长促进剂。生长促进剂使剪切力增加（P < 0.01），且由于宰后蛋白水解活性受限（肌原纤维破碎指数值较低；P = 0.02），背最长肌的韧性有增加趋势（P = 0.06）。饲喂谷物使背最长肌的干物质和肌内脂肪含量增加（分别为P = 0.03和P = 0.05），但感官评定嫩度评分降低（P = 0.01）。生长促进剂使C18:0、C20:0、C18:1的反式异构体和顺-9，反-11 C18:2的比例增加（P≤0.05）。与补饲谷物相比，仅饲喂牧草增加了顺-9，顺-12，顺-15 C18:3以及n-3族的其他几种异构体的比例，且背最长肌中n-6与n-3脂肪酸的比例降低（P < 0.05）。此外，以牧草为基础的日粮增加了瘤胃生物氢化的几种中间产物（顺-9，反-11，顺-15 C18:3；反-11，顺-15 C18:2；反-11 C18:）在肌内脂肪中的浓度（P < 0.01）。饲喂牧草还增加了背最长肌中顺-9，反-11 C18:2的比例（P < 0.01），并降低了反-10 C18:1的浓度（P = 0.03）。得出的结论是，通过牧草育肥且不使用生长促进剂的牛肉生产系统可以满足注重健康的消费者对牛肉品质的要求。
