Machado Neto O R, Chizzotti M L, Ramos E M, Oliveira D M, Lanna D P D, Ribeiro J S, Lopes L S, Descalzo A M, Amorim T R, Ladeira M M
1College of Veterinary Medicine and Animal Science,Universidade Estadual Paulista 'Júlio de Mesquita Filho',Botucatu,São Paulo 18610-307,Brazil.
2Department of Animal Science,Universidade Federal de Viçosa,Viçosa,Minas Gerais 36.570-000,Brazil.
Animal. 2015 Feb;9(2):362-72. doi: 10.1017/S1751731114002377. Epub 2014 Sep 26.
The objective of this study was to evaluate the fatty acid profile and qualitative characteristics of meat from feedlot young bulls fed ground soybean or ground cottonseed, with or without supplementation of vitamin E. A total of 40 Red Norte young bulls, with an initial average age of 20 months, and an initial average BW of 339±15 kg, were allotted in a completely randomized design using a 2×2 factorial arrangement, with two oilseeds, and daily supplementation or not of 2500 IU of vitamin E. The experimental period was for 84 days, which was preceded by an adaptation period of 28 days. The treatments were ground soybean (SB), ground soybean plus vitamin E (SBE), ground cottonseed (CS) and ground cottonseed plus vitamin E (CSE). The percentage of cottonseed and soybean in the diets (dry matter basis) was 24% and 20%, respectively. Diets were isonitrogenous (13% CP) and presented similar amount of ether extract (6.5%). The animals were slaughtered at average live weight of 464±15 kg, and samples were taken from the longissimus dorsi muscle for the measurement of fatty acid concentration and the evaluation of lipid oxidation and color of the beef. Before fatty acid extraction, muscle tissue and subcutaneous fat of the longissimus dorsi were separated to analyze fatty acid profile in both tissues. Supplementation of vitamin E did not affect fatty acid concentration, lipid oxidation and color (P>0.05). Subcutaneous fat from animals fed CS diet had greater C12:0, C16:0 and C18:0 contents (P<0.03). In addition, CS diets reduced the C18:1 and C18:2 cis-9, trans-11 contents in subcutaneous fat (P<0.05). The muscle from animals fed CS tended to higher C16:0 and C18:0 contents (P<0.11), and decreased C18:1, C18:2 cis-9, trans-11 and C18:3 contents (P<0.05) compared with SB. The Δ9-desaturase index was greater in muscle from animals fed SB (P<0.01). At 42 days of age, meat from cattle fed SB had a greater lipid oxidation rate (P<0.05). Meat from animals fed SB diets had less lightness and redness indices than meat from animals fed CS diets after 14 days of age. In conclusion, the addition of ground cottonseed in the finishing diets did increase the saturated fatty acid content of the longissimus dorsi. However, animals fed cottonseed exhibited greater lightness and redness of beef. In this study, the addition of vitamin E did not affect qualitative characteristics of meat.
本研究的目的是评估育肥牛场中以大豆粕或棉籽粕为饲料、添加或不添加维生素E的青年公牛的肉中脂肪酸谱和品质特性。总共40头北红青年公牛，初始平均年龄为20个月，初始平均体重为339±15千克，采用2×2析因设计完全随机分配，有两种油籽，并每日补充或不补充2500国际单位的维生素E。试验期为84天，之前有28天的适应期。处理方式为大豆粕（SB）、大豆粕加维生素E（SBE）、棉籽粕（CS）和棉籽粕加维生素E（CSE）。日粮中棉籽和大豆的百分比（干物质基础）分别为24%和20%。日粮为等氮日粮（13%粗蛋白），醚提取物含量相似（6.5%）。动物在平均活重464±15千克时屠宰，从背最长肌取样测量脂肪酸浓度，并评估牛肉的脂质氧化和颜色。在提取脂肪酸之前，分离背最长肌的肌肉组织和皮下脂肪以分析两种组织中的脂肪酸谱。补充维生素E对脂肪酸浓度、脂质氧化和颜色没有影响（P>0.05）。饲喂CS日粮的动物皮下脂肪中C12:0、C16:0和C18:0的含量更高（P<0.03）。此外，CS日粮降低了皮下脂肪中C18:1和C18:2顺-9，反-11的含量（P<0.05）。与SB相比，饲喂CS的动物的肌肉中C16:0和C18:0的含量倾向于更高（P<0.11），而C18:1、C18:2顺-9，反-11和C18:3的含量降低（P<0.05）。饲喂SB的动物的肌肉中的Δ9-去饱和酶指数更高（P<0.01）。在42日龄时，饲喂SB的牛的肉的脂质氧化速率更高（P<0.05）。14日龄后，饲喂SB日粮的动物的肉的亮度和红色指数低于饲喂CS日粮的动物的肉。总之，育肥日粮中添加棉籽粕确实增加了背最长肌中饱和脂肪酸的含量。然而，饲喂棉籽的动物的牛肉表现出更高的亮度和红色。在本研究中，添加维生素E不影响肉的品质特性。
