不同铬源对肉鸡肌肉品质及氨基酸含量的影响

Effects of different sources of dietary chromium on meat quality and amino acid content of broilers

为了考察日粮中添加不同铬源(均为有机铬)对肉鸡肌肉品质及氨基酸含量的影响,为铬资源的合理利用提供科学依据。特选用1日龄爱拔益加(Arbor Acres,AA)肉鸡792只,随机分成6个处理组,每个处理4个重复,每个重复33只;对照组饲喂玉米-豆粕型基础日粮,试验组饲喂在基础日粮中分别添加酵母铬0.2mg/kg、吡啶甲酸铬0.2mg/kg或蛋氨酸铬0.1mg/kg(Ⅰ)、0.2mg/kg(Ⅱ)、0.6mg/kg(Ⅲ)型日粮(以Cr3+计),自由采食、饮水,试验期49d。结果表明:1)酵母铬和蛋氨酸铬(Ⅱ)能显著降低胸肌纤维密度(P<0.05),酵母铬还显著降低了腿肌纤维面积(P<0.05);蛋氨酸铬(Ⅰ)组能显著降低胸肌和腿肌维纤维面积(P<0.05);2)吡啶甲酸铬能显著降低胸肌蛋白质量浓度(P<0.05),蛋氨酸铬(Ⅱ)能显著降低胸肌粗脂肪含量(P<0.05);3)除蛋氨酸铬(Ⅱ)能显著提高腿肌总抗氧化能力外(P<0.05),不同铬源对胸肌和腿肌其他抗氧化指标的影响差异均不显著(P>0.05);蛋氨酸铬(Ⅲ)能显著提高胸肌总抗氧化能力、提高腿肌过氧化氢酶活性(P<0.05);4)除吡啶甲酸铬显著降低胸肌丙氨酸含量外(P<0.05),不同铬源对肌肉其他氨基酸含量影响均不显著(P>0.05)。以上结果提示,与对照组相比,酵母铬和蛋氨酸铬较吡啶甲酸铬对改善肉鸡肌肉组织结构及抗氧化性能效果明显,补铬对改善肉鸡肌肉氨基酸含量、提高肉品质效果不明显(P>0.05)。

Summary Chromium as a beneficial element was occasionally indicated by more and more investigations reported. Trivalent chromium Cr（Ⅲ ） has been accepted as an essential element for 30 years which can affect the growth performance, carcass characteristics, pork quality, reproduction and tissue deposition of domestic animals that were fed with Cr（Ⅲ ） supplementation in diet through changes protein, nucleic acid and lipid metabolism. Chromium is found in GTF-like forms in the livers of mammals given inorganic chromium, but this could reflect the manifold effects of insulin rather than further biochemical roles for chromium. Moreover some other reports indicated Cr（ Ⅲ ）appeared not to be an essential element, and its potential effects on domestic animals might be considered pharmacological. I.imited research is available for addressing the effect of Cr on meat quality of broiler elucidated by determining the fiber muscle density, total antioxidant capacity and amino acid content. Thus, the purpose of present experiment was to evaluate the effects of three different sources of chromium （yeast chromium, chromium picolinate and methionine chromium） on meat quality and amino acid content of Arbor Acres （AA） broilers. Seven hundred and ninety-two one dayold Arbor Acres broilers were randomly allocated to six dietary treatments. Each treatment had four replicates （cages） with thirty three broilers per cage, respectively. The dietary treatments were： 1） corn-soybean meal basal （B： according to NRC, 1994）, 2） B 2. 0.2 mg/kg of Cr （as yeast chromium）, 3） B＋0.2 mg/kg of Cr （as chromium picolinate）, 4） B ＋ 0.1 mg/kg （as methionine chromium; Ⅰ）, 5） B ＋0.2 mg/kg （as methionine chromium; Ⅱ ）, 6） B＋ 0. 6 mg/kg of Cr （as methionine chromium; Ⅲ）. The fiber density, fiber areas and its antioxidant index of leg muscle, as well as amino acids content of muscle were determined. The results showed that the fiber density of breast muscle and fiber areas of leg muscle were reduced （P 〈 0.05） in broilers fed with yeast chromium diets, fiber density of breast muscle was reduced （P 〈 0.05） in broilers fed with methionine chromium（ Ⅱ ） diets, fiber areas of breast muscle and leg muscle were reduced （P 〈 0.05） in broilers fed with methionine chromium （ Ⅰ ） diets compared with broilers fed with the control diets. Protein content of breast muscle was reduced （P 〈 0.05） in broilers fed with chromium picolinate diets, and fat content of breast muscle was reduced （P 〈 0.05） in broilers fed with methionine chromium （ Ⅱ） diets. Antioxidant index of breast muscle and leg muscle were not affected （P 〉 0.05） by treatments, with the exception that, total antioxidant capacity （T-AOC） of leg muscle from broilers fed with methionine chromium （ Ⅲ ）, total antioxidant capacity （T- AOC） of breast muscle and catalase （CAT） of leg muscle from broilers fed with methionine chromium （Ⅲ ）, all of these had an increased （P 〈 0.05） than broilers fed with the control diets. Main amino acids of muscle were not affected （P 〉 0.05） among treatments, with the exception that the alanine content of breast muscle in broilers fed with chromium picolinate reduced （P 〈 0, 05） compared with that of broilers fed with the control diets. These suggested that dietary supplementation of yeast chromium or methionine chromium in broilers had a significant effect on muscular tissue structure and oxidation resistance of muscle; however, the main amino acids of muscle were not affected by treatments.