天门冬氨酸镁添加水平对肉仔鸡生长性能及肉品质的影响

试验研究天门冬氨酸镁(MgAsp)添加水平对肉仔鸡生长性能及肉品质的影响。选用240只22日龄的艾维茵肉仔鸡,随机分成5组,每组6个重复,每个重复8只鸡。试验期为3周。分别添加MgAsp使镁的添加水平分别为0、0.06%、0.12%、0.20%、0.30%。结果表明,饲料中添加镁对肉仔鸡的日平均增重和料重比无显著影响(P>0.05);0.20%镁能显著改善肉质,提高胸肌蛋白和腿肌蛋白含量;降低脂肪、总胆固醇、甘油三酯和低密度脂蛋白含量(P<0.05),对腿肌脂肪含量影响不显著(P>0.05)。研究结果表明,日粮中添加天门冬氨酸镁对肉仔鸡的生产性能无显著影响;添加0.20%镁水平可以显著提高鸡肉肉品质。     

不同镁源相对生物学利用率的评价

360只1日龄的AA肉仔鸡随机分成10组(3×3 1),每组设6个重复,每个重复6只公雏,研究3种镁源的相对生物学利用。三种镁源:氧化镁(MgO)、天门冬氨酸镁(MgAsp)、天门冬氨酸螯合镁(MgdiAsp),每种镁的添加水平为0.9、1.8、2.7g/kg,不加镁的处理组做为对照。试验结果表明,血清镁的浓度随各镁源添加水平提高线性提高(P<0.01)。肝脏镁的含量随日粮中MgO、MgAsp添加量的提高呈二次曲线性提高(P<0.01)。MgAsp比MgO更有效提高血清和肝脏中的镁含量(P<0.01)。MgdiAsp添加组肉仔鸡血清和肝脏中的镁含量最高。肝脏过氧化氢酶(CAT)的活性随MgAsp或MgdiAsp添加量的增加线性提高(P<0.01),而随MgO添加量的增加呈二次曲线性提高(P<0.05)。MgAsp比MgO更有效地提高肝脏CAT的活性,MgdiAsp供应组肉仔鸡肝脏中CAT的活性最高(P<0.01)。肝脏丙二醛(MDA)的含量随日粮镁添加量的增加线性降低(P<0.05),有机镁比无机镁更有利于降低肝脏中MDA的含量(P<0.01)。本研究结果表明,日粮中添加镁可以改善肉仔鸡的镁营养状态,提高肉仔鸡肝脏抗氧化酶的活性,降低脂质过氧化水平,有机镁的效果优于无机镁。     

日粮中添加天门冬氨酸镁对肉仔鸡肝脏和腿肌脂质过氧化状态的影响

研究日粮添加天门冬氨酸镁（MgAsp）对肉仔鸡肝脏和腿肌脂质过氧化状态的影响及其机理。将128只22日龄的AA肉仔鸡随机分配到对照组和加镁日粮组,每组8个重复,每个重复8只鸡,以玉米、豆粕为主要原料配制对照组日粮,在此基础上添加1％的MgAsp作为加镁组日粮。42日龄时,每个重复随机抽取1只鸡,颈静脉放血处死,收集血清、肝脏和腿肌等样品。试验结果表明,与对照组相比,加镁组肉仔鸡血清、腿肌和肝脏镁的含量分别提高了22％、21％和29％（P〈0．01）,加镁组肉仔鸡肝脏和腿肌中丙二醛（MDA）的含量分别降低了24%（P〈0．01）和29％（P〈0．01）,加镁组肉仔鸡肝脏中过氧化氢酶（CAT）和总超氧化物歧化酶（SOD）的活性分别提高了25％（P〈0．01）和14％（P〈0．05）,腿肌CAT的活性提高了37％（P〈0．01）,日粮添加MgAsp显著降低腿肌中活性氧（ROS）的含量（P〈0．01）。两组肉仔鸡腿肌和肝脏中不饱和脂肪酸的总含量差异不显著（P〉0．05）。上述结果说明,玉米-豆粕日粮中添加MgAsp可以有效降低肝脏和腿肌中MDA的产量;腿肌中CAT活性的提高和ROS产量的降低是日粮添加MgAsp降低腿肌中脂质过氧化水平的原因;肝脏中CAT和SOD活性的提高是日粮添加MgAsp降低肝脏中脂质过氧化水平的原因。     

日粮中添加谷氨酰胺对肉仔鸡肉品质和抗氧化指标的影响

本试验旨在研究外源添加谷氨酰胺(Gln)对肉仔鸡肉品质的影响,并对肌肉中风味物质和抗氧化指标进行分析,探讨其对肉质的影响机理.选用1日龄艾维茵肉仔鸡360羽,随机分成4组(每组6个重复,每个重复15羽),对照组饲喂基础日粮,试验组饲喂在基础日粮中分别添加了0.5%、1.0%、1.5%谷氨酰胺的试验日粮.于42日龄进行屠宰取样,测定各项指标.结果表明,与对照组相比,各试验组鸡的肌肉系水力和pH均有所提高(P>0.05),皮脂厚和肌间脂肪宽度有所降低(P>0.05);肌肉中胶原蛋白含量显著增加(P<0.05);胸肌中必需氨基酸和鲜味氨基酸含量都显著增加(P<0.05),谷氨酸和苯丙氨酸含量亦显著增加(P<0.05);1.0%和1.5%添加组肌苷酸含量有所提高(P>0.05);1.0%Gln组胸肌中丙二醛(MDA)含量显著降低(P<0.05),各试验组胸肌中超氧化物歧化酶(SOD)活力有升高的趋势(P>0.05);0.5%和1.0%Gln组血清中SOD和谷胱甘肽过氧化物酶(GSH-Px)活力显著提高(P<0.05).以上表明,日粮添加Gln可改善肉仔鸡肉品质,提高鸡肉的鲜味和抗氧化能力,以0.5%的Gln添加量效果最佳.     

日粮中添加酵母培养物对肉仔鸡生长性能、肉品质和肠道菌群的影响

试验旨在研究日粮中添加不同水平酵母培养物对肉仔鸡生长性能、肉品质和肠道菌群的影响。选用432只1日龄、初始体重为（41.73±0.15）g的AA商品代肉仔鸡公雏,随机分为4个处理组（分别在基础日粮中添加0、0.1%、0.2%和0.3%的酵母培养物）,每组6个重复,每个重复18只鸡。试验期42 d,分为1~21和22~42 d两个阶段,试验期间记录采食量、体重和死淘率,试验结束时每个重复选择1只与平均体重接近的肉仔鸡空腹12 h后进行屠宰,测定其屠宰性能和肠道微生物数量。结果显示,与对照组相比,日粮中添加0.2%和0.3%酵母培养物能够显著提高肉仔鸡42 d的体重和试验全期平均日增重（P< 0.05）。且当添加量为0.2%时,能显著提高肉仔鸡22~42 d平均日增重（P< 0.05）,显著降低料重比（P< 0.05）;显著提高试验全期平均日增重和平均日采食量（P< 0.05）,显著降低试验全期料重比（P< 0.05）。同时,添加酵母培养物还可显著降低鸡肉的滴水损失和大肠杆菌数量（P< 0.05）,并显著增加盲肠双歧杆菌数量（P< 0.05）。综上所述,肉仔鸡日粮中添加0.2%酵母培养物的效果最佳,能够显著提高肉鸡生长性能,提高肌肉的系水力,改善其肌肉品质。同时,还能有效增加肉鸡盲肠中有益菌双歧杆菌数量和减少有害菌大肠杆菌数量。     

日粮添加混合发酵饲料对樱桃谷肉鸭生长性能、胴体品质和肌肉脂肪代谢的影响

为了探究在日粮中添加麸皮-玉米-豆粕混合发酵饲料对樱桃谷肉鸭生长,胸肌肉品质以及胸肌脂肪代谢的影响,试验选用720只1日龄雌雄各半的樱桃谷肉鸭,随机分为4组,每组6个重复,每个重复30只。对照组饲喂基础日粮,试验组在日粮中添加2.5%、5.0%和7.5%的混合发酵饲料(fermented mixture feed, FMF)。肉鸭采用两阶段饲喂,试验周期为42 d。试验结果表明：日粮添加FMF对肉鸭的生长性能和胴体屠宰率均无显著影响,但显著增加了2.5%和5%FMF组肉鸭宰后45 min胸肌的红度值(P<0.05)。相较于对照组,日粮中添加2.5%FMF显著增加了肉鸭胸肌肌纤维横截面积(P<0.05),但显著降低了MyHC-I的蛋白表达量(P<0.05)。此外,日粮中添加7.5%FMF显著上调了胸肌中甘油三酯水平(P<0.05),并且所有FMF组的FASN的蛋白表达量都显著上升(P<0.05),5%和7.5%FMF组胸肌中PNPLA2的蛋白水平也显著(P<0.05)上升。由此表明：日粮中添加2.5%的混合发酵饲料能显著改善肉鸭的肌肉品质,但并不影响肉...     

白酒糟酵母培养物对肉仔鸡生长性能、血清抗氧化指标和肠道形态结构的影响

本试验旨在研究白酒糟酵母培养物(DGYC)对肉仔鸡生长性能、血清抗氧化指标和肠道形态结构的影响,以确定肉仔鸡饲粮中DGYC的适宜添加水平。选取525只1日龄健康的爱拔益加肉仔鸡公雏,随机分为5个组,每组7个重复,每个重复15只鸡。对照组饲喂基础饲粮,试验组在基础饲粮基础上分别添加0.25%、0.50%、1.00%和2.00%的DGYC。试验期42 d。结果表明:1)与对照组相比,饲粮添加1.00%DGYC提高了肉仔鸡生长后期(22～42日龄)平均日增重(0.05≤P<0.10),显著降低了料重比(P<0.05),且均随DGYC添加水平提高呈二次曲线变化(P<0.05)。2)与对照组相比,饲粮添加0.25%DGYC显著降低了肉仔鸡21日龄腹脂率(P<0.05),显著提高了42日龄腿肌率(P<0.05);饲粮添加0.50%和1.00%DGYC有降低肉仔鸡42日龄胸肌滴水损失的趋势(0.05≤P<0.10)。3)饲粮添加DGYC线性提高了肉仔鸡21和42日龄血清谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活性和总抗氧化能力(T-AOC)(P<0.05);饲粮添加DGYC二次性提高了肉仔鸡21日龄血清GSH-Px活性以及42日龄血清SOD活性和T-AOC (P<0.05)。与对照组相比,饲粮添加1.00%DGYC显著提高了肉仔鸡21日龄血清GSH-Px活性(P<0.05);饲粮添加0.50%、1.00%和2.00%DGYC显著提高了肉仔鸡21日龄血清SOD活性(P<0.05),显著提高了肉仔鸡21和42日龄血清T-AOC(P<0.05);饲粮添加0.50%和1.00%DGYC显著提高了肉仔鸡42日龄血清SOD活性(P<0.05)。4) 1.00%DGYC添加组肉仔鸡21日龄空肠绒毛高度和42日龄绒毛高度/隐窝深度(V/C)显著高于对照组(P<0.05),且均随DGYC添加水平提高呈二次性升高(P <0.05)。5)肉仔鸡生长性能、血清抗氧化指标和空肠形态结构随DGYC添加水平升高存在二次曲线效应。二次曲线拟合结果表明,DGYC添加水平为0.9%～1.1%时,空肠形态结构最佳;添加水平为1.1%～1.2%时,生长性能和血清抗氧化能力最佳。由此可见,饲粮添加DGYC能提高肉仔鸡血清抗氧化能力,改善空肠黏膜形态结构,从而改善生长性能。以肉仔鸡生长性能、血清抗氧化指标和肠黏膜形态结构为判断指标,推荐肉仔鸡基础饲粮中DGYC添加水平为0.9%～1.2%。     

超氧化物歧化酶模拟物对肉仔鸡肉品质和超氧化物歧化酶活性的影响

本试验旨在研究日粮中添加不同水平超氧化物歧化酶模拟物(superoxdie dismutase mimics,SODm)对肉仔鸡生长性能、肉品质及超氧化物歧化酶(SOD)活性的影响。采用单因子试验设计,选取1日龄爱拔益加(AA)肉仔鸡公雏432只,随机分成6组,每组6个重复,每个重复12只。对照组饲喂基础日粮,试验组在基础日粮中分别添加0.10%、0.15%、0.20%、0.25%、0.30%SODm,试验期42 d。结果表明:①日粮添加SODm对肉仔鸡平均日采食量(ADFI)、平均日增重(ADG)和料重比(F/G)均无显著影响(P>0.05)。②添加0.20%、0.25%和0.30%SODm组胸肌亮度(L~*)值显著低于对照组(P<0.05);除0.10%SODm组外,SODm各组胸肌剪切力均显著低于对照组,滴水损失显著高于对照组(P<0.05)。SODm各组腿肌L~*值均显著低于对照组(P<0.05);0.10%和0.15%SODm组腿肌剪切力显著低于对照组(P<0.05)。③21日龄时,与对照组相比,0.30%SODm组血清SOD活性显著降低(P<0.05),其他SODm组血清SOD活性均有提高,但差异不显著(P>0.05);42日龄时,添加SODm各组血清SOD活性均显著高于对照组(P<0.05)。④21日龄时,SODm各组肝脏SOD活性均显著高于对照组(P<0.05);添加SODm对胸肌和心脏SOD活性无显著影响(P>0.05)。42日龄时,添加0.15%和0.25%SODm组肝脏和心脏SOD活性显著高于对照组(P<0.05);0.25%和0.30%SODm组胸肌和腿肌SOD活性显著高于对照组(P<0.05)。综上,本试验条件下,在日粮中添加SODm对肉仔鸡生长性能无显著影响;添加0.15%～0.25%SODm可提高肉仔鸡体内SOD活性,降低肌肉亮度和剪切力,改善肌肉嫩度。     

黄花蒿多糖对肉仔鸡生长性能、肌肉抗氧化指标及肉品质的影响

试验旨在探讨饲粮中添加不同剂量的黄花蒿多糖（Artemisia annua L. polysaccharide,AAP）对肉仔鸡生长性能、胸肌和腿肌抗氧化指标及肉品质的影响。试验选取健康、体重相近[（44.19±0.25）g]的1日龄AA肉仔鸡240只,随机分为基础饲粮组（对照）和在基础饲粮中分别添加250、500、750 mg/kg和1 000 mg/kg AAP的试验组。每组6个重复笼,每笼8只鸡,公母各半。饲养期为42 d。结果表明：随着AAP添加剂量的递增,试验前期肉仔鸡的体增重（BWG）和21 d的末体重（FBW）均呈显著的一次线性升高（P<0.05）,且在42 d时,肉仔鸡胸肌、腿肌中谷胱甘肽过氧化物酶（GSH-Px）活性和屠宰后45 min的胸肌pH均呈显著的二次曲线升高（P<0.05）,胸肌、腿肌的亮度值和剪切力及腿肌中丙二醛含量均呈显著的一次线性降低（P<0.05）,与对照组相比,饲粮中添加750 mg/kg AAP显著提高了肉仔鸡42 d的FBW、试验全期的BWG、试验后期的饲料转化效率（FE）和腿肌中GSH-Px的活性（P<0.05）,极显...     

饲粮镁对肉仔鸡生长、组织镁浓度及抗氧化功能的影响

研究比较了天门冬氨酸镁和氧化镁对肉仔鸡镁营养状态及肝脏和脾脏等组织抗氧化酶能力的影响。将252只1日龄的AA肉仔鸡随机分为7个处理组,每个处理6个重复,每个重复6只鸡。天门冬氨酸镁和氧化镁的添加水平为0.9、1.8、2.7g/kg日粮,基础日粮组作为不添加镁的对照组。日粮中添加镁能显著提高血清、肝脏和脾脏中的镁浓度(P<0.01),天门冬氨酸镁比氧化镁更能有效地提高血清和肝脏中的镁含量(P<0.01)。肝脏过氧化氢酶(CAT)的活性,随天门冬氨酸镁添加量的增加线性增加(P<0.01),随氧化镁添加量的增加呈二次曲线增加(P<0.05)。天门冬氨酸镁比氧化镁更有效地增强肝脏中CAT的活性(P<0.01)。脾脏CAT的活性随天门冬氨酸镁(P<0.05)或氧化镁(P<0.01)添加量的增加线性增加。肝脏(P<0.05)和脾脏(P<0.01)丙二醛MDA的浓度随氧化镁或天门冬氨酸镁添加量的增加线性降低。天门冬氨酸镁比氧化镁更有效地降低肝脏中的MDA浓度(P<0.01)。结果表明:日粮中添加镁能显著改善肉仔鸡各种组织中镁的含量,并能提高肝脏和脾脏等组织中抗氧化酶的活性,降低脂质过氧化水平。     

Effects of dietary supplementation with conjugated linoleic acid on fatty acid composition and lipid oxidation in chicken breast meat

We investigated the effects of dietary conjugated linoleic acid (CLA) on fatty acid composition and lipid oxidation in breast meat of broiler chickens. Broiler chickens (28-day-old females) were fed diets containing experimental oils at 20 g/kg diet for 28 days. The experimental oils consisted of either a 2:0, 1:1, or a 0:2 (wt : wt) ratio of safflower oil (high linoleic acid content) to a commercial CLA mixture. In this study, dietary CLA supplementation significantly increased the composition and content of CLA in chicken meat. The predominant CLA in meat from birds with supplemented diets was the cis -9, trans -11 isomer. The proportion of saturated fatty acid in meat significantly increased with increasing CLA supplementation, with a corresponding decrease in monounsaturated fatty acid. Dietary CLA also reduced thiobarbituric acid reactive substances (TBARS) values in raw meat during storage at 4°C for 5 days. These results provide evidence that CLA feeding is a practical strategy not only for adding nutritional benefits to chicken meat but also for improving meat quality including oxidative stability.     

日粮添加荷叶提取物对黄羽肉鸡抗氧化功能及肌肉品质的影响

本试验选择28日龄岭南黄慢速型黄羽肉鸡1200只,随机分成3组,每组10个重复,公母各半,每个重复40只鸡。对照组饲喂基础日粮,试验组分别饲喂基础日粮添加0.1%和0.2%荷叶提取物,饲养至120日龄出栏,研究日粮添加荷叶提取物对黄羽肉鸡肉品质及抗氧化活性的影响。结果显示,在日粮中添加0.1%荷叶提取物能够显著提高黄羽肉鸡公鸡肌肉pH_{45 min}（P<0.05）及母鸡肉色b^* 值（P<0.05）;显著提高公鸡肌肉总抗氧化能力（P<0.05）和谷胱甘肽过氧化物酶（P<0.01）,降低丙二醛含量（P<0.05）;对母鸡抗氧化活性也表现出与公鸡一致的作用趋势,提高胸肌总抗氧化能力（P<0.1）,显著提高GSH-Px活性（P<0.05）,降低MDA含量（P<0.1）。与对照组相比,日粮添加0.2%荷叶提取物也可以显著提高母鸡肉色b^* 值（P<0.05）,但对本试验中其他肉品质指标及抗氧化指标均无显著性影响。由此可见,日粮中添加0.1%荷叶提取物可以增强黄羽肉鸡的抗氧化能力,从而改善肌肉品质。     

Impact of dietary chitosan oligosaccharide and its effects on coccidia challenge in broiler chickens

ABSTRACT

1. Two experiments were conducted, the first to determine the optimum inclusion of chitosan oligosaccharide (COS) in broiler diets to support growth performance, digestive functions, intestinal morphology, and immune organs. The second experiment evaluated the immune-protective properties of COS on broiler chickens during coccidia challenge (CC).

2. Experiment 1 investigated the effect of graded dietary concentration of COS in the diets of broiler chickens using eight cage replicates for each of the six diets. A corn-soybean meal-based diet was used as the basal diet and supplemented with 0.0, 0.5, 1.0, 1.5, 2.0, or 2.5 g of COS/kg feed to form the six treatments.

3. The diet supplemented with 1.0 g COS/kg of feed provided the optimal inclusion level for broiler chickens regarding body weight (BW) gain, jejunal villus height, villus height to crypt depth ratio, and ileal energy digestibility at d 22 of age.

4. Experiment 2 investigated the immune-protective properties of COS in broiler chickens during CC. A total of 224 male broiler chicks were randomly assigned to eight replicate cages in a 2 × 2 factorial arrangement of treatments with two COS concentrations (0 or 1 g of COS/kg of diet), with or without CC.

5. On d 18 of age, birds in the CC group received twice the recommended coccidia vaccine dose of 30 doses/kg BW.

6. Coccidia challenge reduced (P < 0.05) and dietary COS increased (P < 0.05) BW gain, and feed intake. Dietary COS mitigated (P < 0.05) the CC-induced effects on gain:feed. Dietary COS supplementation attenuated the CC-induced effects (P < 0.05) on the expression of occludin genes.

7. In conclusion, dietary COS improved performance, and the immune-related beneficial impact of COS supplementation was associated with reduced expression of pro-inflammatory cytokine genes.     

Dietary supplementation of phenyllactic acid on growth performance,immune response,cecal microbial population,and meat quality attributes of broiler chickens

A total of 750 one-day-old male broiler chicks were randomly fed 5 dietary treatments with 5 replicate pens per treatment. The 5 dietary treatments fed for 42 d were a corn-soybean meal basal diet without antibiotic (control); a mixture of 10 ppm of avilamycin + 60 ppm of salinomycin as antibiotic growth promoters (AGP); 0.1% phenyllactic acid (PLA); 0.2% PLA; and 0.4% PLA. The BW gain and FE were significantly improved in AGP and PLA groups compared with control group. The white blood cells and heterophil counts were significantly higher in the PLA-supplemented groups compared with AGP and control groups, but the heterophil-to-lymphocyte ratio was lower in the control group than other groups. The plasma IgY concentration was significantly increased in birds fed PLA-supplemented diets, but the plasma IgA and IgM concentrations were not different among the treatment groups. In addition, the antibody titer against Newcastle disease virus was significantly higher in PLA-treated compared with control and AGP-treated groups. Neither PLA nor AGP treatments affected the cecal aerobes andSalmonella content; however, cecalLactobacillus population increased in chickens fed 0.1% PLA, and total coliform bacteria population significantly decreased in chickens fed various levels of PLA and AGP. Dietary supplementation of PLA did not affect the pH, lightness, and redness of breast meat, but the water-holding capacity and shear force value increased and the yellowness decreased significantly when birds were fed PLA. It was concluded that dietary supplementation of 0.1 and 0.2% PLA improves BW gain and FE of broiler chickens. In addition, PLA supplementation increases the immune characteristics and the number of lactic acid bacteria, decreases the number of coliform bacteria, and improves the meat quality attributes of broiler chickens. Thus, dietary PLA could be a viable alternative to antibiotics in broiler diets.     

饲粮短期高剂量添加天冬氨酸镁对猪肉品质的影响

本试验研究了在基础日粮中短期添加不同水平的天冬氨酸镁对猪肉品质的影响。试验共分4个处理,每个处理6头猪。处理组镁(天冬氨酸镁)的添加水平分别为0、1 500、2 500和3 500 mg/kg。结果表明:屠宰前7 d饲粮添加天冬氨酸镁提高了猪肉品质,背最长肌肉中镁的含量分别比对照组提高了10.35%(P<0.05)、16.83%和18.61%(P<0.01),血清中镁的浓度分别比对照组增加了14.29%、27.14%和34.29%(P<0.01);显著提高了猪肉的初始pH(6.16~6.50)和最终pH(5.61~5.75)(P<0.05);对肉色评分改善显著(P<0.05);显著降低了滴水损失(P<0.05);但对猪的屠宰率、瘦肉率、背膘厚、眼肌厚度和肌肉中胶原蛋白含量等无显著影响(P>0.05)。回归分析结果表明:当镁的添加量在2 500~3 200 mg/kg时,对pH、滴水损失和肉色的改善作用达到最大,此时血清和肌肉中镁的含量约为0.90 mmol/L和241 mg/kg。     

饲粮添加共轭亚油酸对肉仔鸡肠道黏膜免疫反应的影响

本试验旨在研究饲粮添加共轭亚油酸(conjugated linoleic acid,CLA)对肉仔鸡肠道黏膜免疫反应的影响。试验选用72只1日龄健康、体重相近的爱拔益加(AA)雄性肉仔鸡,随机分配到对照组和CLA组,分别饲喂基础饲粮和在基础饲粮中添加1%CLA的饲粮,每组6个重复,每个重复6只鸡。21日龄屠宰取样。结果表明:CLA组肉仔鸡空肠食糜分泌型免疫球蛋白A(secretory immunoglobulin A,SIgA)含量(P<0.01)和空肠SIgA基因mRNA表达水平(P<0.01)均高于对照组;饲粮添加CLA显著提高肉仔鸡空肠过氧化物酶体增殖物激活受体γ(PPARγ)基因mRNA表达水平(P<0.01),但转化生长因子β4(transforming growth factor-β4,TGFβ4)基因mRNA表达水平在2组之间没有显著差异(P>0.05);CLA组肉仔鸡Peyer氏结CD8+T细胞亚群百分数(P<0.01)和淋巴细胞转化率(P<0.05)均显著高于对照组。由此可见,饲粮添加1%CLA提高了21日龄肉仔鸡空肠SIgA水平,激活PPARγ可能是CLA调节SIgA表达的途径之一。饲粮添加1%CLA影响21日龄肉仔鸡空肠黏膜细胞免疫功能。     

Comparison of effects of dietary olive oil,tallow and vitamin E on the quality of broiler meat and meat products

1. The effect of dietary fat and vitamin E supplementation on quality attributes (drip loss, oxidative stability, sensory quality) in chicken meat and meat products was investigated. Broiler chicks were fed on diets containing tallow (60 g/kg) or olive oil (60 g/kg) at a basal (30 mg/kg diet) or supplemental (200 mg/kg diet) concentration of alpha-tocopheryl acetate for 8 weeks. The alpha-tocopherol content and fatty acid composition of breast and thigh meat was determined. Drip loss was determined in breast fillets. Lipid oxidation (thiobarbituric acid-reacting substances/TBARS) and sensory quality (warmed-over flavour development/WOF) were assessed in minced thigh meat during storage. 2. Dietary olive oil increased the ratio of monounsaturated to saturated fatty acids (MUFA/SFA) in the diets. In breast and thigh, this resulted in approximately a two-fold increase in the MUFA/SFA ratio. Supplemental alpha-tocopherol increased the alpha-tocopherol content of muscles. 3. Dietary fat did not influence drip loss in thawed breast fillets during refrigerated storage, but supplemental alpha-tocopherol reduced drip loss. 4. TBARS and WOF development in minced thigh meat patties were also reduced by supplemental alpha-tocopherol following frozen storage, or cooking and refrigerated storage. Storage stability was not adversely affected by dietary fat. 5. Overall, the results showed that increasing the monounsaturated profile of chicken meat lipids did not adversely affect quality characteristics. Dietary alpha-tocopherol supplementation was a more important factor in the determination of broiler meat quality.     

Dietary selenium increases vitamin E contents of egg yolk and chicken meat

1. The influence of different forms of dietary selenium (Se) on vitamin E (alpha-tocopherol) and Se contents of egg yolk and chicken meat was investigated. 2. Eggs were collected from laying hens subjected to 4 different dietary treatments after 24 weeks of age. Treatments compared the effects of inorganic Se supplementation (selenite) to those of organic (Se-enriched yeast, Se-enriched alga Chlorella) supplements. In a second experiment the effect of the above organic dietary Se supplementation on the alpha-tocopherol contents of meat from broiler chickens was evaluated. 3. Dietary Se supplementation increased the alpha-tocopherol content of egg yolks from 297 mg/kg dry matter in treatment without supplementation to 311 mg/kg when selenium was supplemented as selenite, and to 370-375 mg/kg when organic supplements were used. The Se and alpha-tocopherol contents of breast and thigh meat in broilers were significantly increased by organic dietary Se supplementation. 4. The inclusion of organic dietary Se sources in the diets of laying hens and broilers would enhance the nutritional value (vitamin E and Se contents) of products (eggs and meat) for human consumption.     

宰前短期添加天冬氨酸镁和维生素D_3对育肥猪肉品质及μ-Calpain与Calpastatin基因表达的影响

试验考察宰前添加天冬氨酸镁(MgAsp)与维生素D3(VD3)对试猪血液理化指标、猪肉品质以及μ-Calpain和Calpastatin基因mRNA含量的影响。选体重约90 kg DLY杂交猪48头,随机分到4个处理:对照、加MgAsp、加VD3和加MgAsp与VD3。试验期为9 d,试验结束后选取24头进行屠宰。结果表明:宰前短期添加MgAsp和VD3对育肥猪胴体品质无影响;与对照相比,添加MgAsp提高血清镁含量(P<0.05),添加VD3提高血清磷(P<0.05)和钙的含量,MgAsp和VD3联合添加可进一步提高血清镁含量(P<0.01);添加MgAsp降低臀肌L值(P<0.01),并有提高肌肉pH值和降低滴水损失的趋势,提高了μ-Calpain与Calpastatin mRNA的比值,改善了嫩度;添加VD3降低了臀肌的L24h值(P<0.05),有提高pH和嫩度的趋势;MgAsp和VD3联合添加除对剪切力略有改善而外,对其他肉质指标并没有进一步改善。