连翘提取物对肉仔鸡肌肉抗氧化活性的影响

本研究旨在探讨连翘提取物对内仔鸡胸肌抗氧化和脂质过氧化指标的影响,为连翘提取物在养鸡生产中的应用提供试验依据.试验选用1日龄健康的爱拔益加肉公雏252只,平均体重为(38.8±1.3)g,研究连翘提取物(FSE)对热应激(32±1)℃肉鸡肌肉抗氧化能力的影响.试验期为42 d.将肉仔鸡随机分为3个处理,每个处理14个重复,每个重复6只鸡.日粮处理组分别为(1)空白对照组(NC)基础日粮;(2)维生素C组(PC)基础日粮 200ng/kg维生素C;(3)连翘提取物组(FSE)基础日粮 100 mg/kg FSE.试验第21天和第42天屠宰取胸肌样品,检测抗氧化指标.结果表明,在试验后期,与NC空白组和维生素C组相比,FSE组肉仔鸡的超氧化物歧化酶(SOD)(P＜0.05)、谷胱甘肤过氧化物酶(GSH-Px)和总抗氧化能力(T-AOC)含量增加,其抗氧化活性好于维生素C组,而丙二醛(MDA)含量显著降低(P＜0.05).FSE通过清除自由基途径,缓解热应激诱导的活性氧对机体细胞膜的损伤,进而改善肌肉抗氧化活性及提高肉品质.     

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%。     

丹参提取剩余物对肉仔鸡生产性能和血清抗氧化指标的影响

试验旨在研究日粮中添加不同水平的丹参提取剩余物对肉仔鸡生产性能和血清抗氧化指标的影响。选用1日龄爱拔益加(AA)肉仔鸡320只,随机分成4个处理,每个处理8个重复,每个重复10只鸡。处理1为对照组,饲喂基础日粮;处理2、3、4为在基础日粮中分别添加0.3%、0.5%和1%丹参提取剩余物的试验组。试验第21、42日龄,空腹称重,统计耗料量,计算生产性能;翅静脉采血,测定血清总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)活性、谷胱甘肽过氧化物酶(GSH-Px)活性和丙二醛(MDA)含量。结果显示,日粮中添加0.3%、0.5%和1%丹参提取剩余物对于肉仔鸡的生产性能没有显著影响(P>0.05)。日粮中添加0.3%丹参提取剩余物对于肉仔鸡血清抗氧化指标的影响差异不显著(P>0.05);日粮中添加0.5%丹参提取剩余物对于肉仔鸡血清总抗氧化能力(T-AOC)影响差异不显著(P>0.05),可以提高超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性,但是差异不显著(P>0.05);日粮中添加1%丹参提取剩余物可以显著提高肉仔鸡血清总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)活性、谷胱甘肽过氧化物酶(GSH-Px)活性(P<0.05),同时可以显著降低血清丙二醛(MDA)含量(P<0.05)。由此可见,在肉仔鸡日粮中添加丹参提取剩余物可以提高肉仔鸡的抗氧化能力,其中添加比例为1%时作用效果最佳。     

万寿菊提取物对肉鸡生长性能、色素沉积、抗氧化和肉质的影响

文章旨在研究饲粮添加万寿菊提取物对肉鸡生长性能、色素沉积、抗氧化能力和肉品质的影响。试验将480只1日龄肉仔鸡随机分为5组,每组6个重复,每个重复16只鸡。对照组饲喂基础日粮,其他处理组分别在基础日粮中添加0.08%、0.16%、0.32%、0.64%万寿菊提取物(其叶黄素含量分别是20、40、80和160mg/kg)。结果表明,日粮添加万寿菊提取物可显著增加腿肌、皮肤的黄度值及腿肌的红度值,且随着添加水平的升高线性升高(P 0.05)。此外,万寿菊提取物显著提高肝脏和腿肌的总抗氧化能力和超氧化物歧化酶活性(P 0.05),显著降低肝脏和腿肌丙二醛含量(P 0.05)。日粮添加万寿菊提取物可显著降低腿肌的滴水损失和剪切力(P 0.05),但万寿菊提取物对肉鸡生长性能无显著影响(P 0.05)。综上所述,日粮中添加万寿菊提取物可显著提高肉鸡胴体黄度值、抗氧化能力和肉品质。     

植物提取物对肉鸭生长性能和血清抗氧化指标的影响

试验旨在探讨植物提取物饲料添加剂康华安对樱桃谷肉鸭生产性能和血清抗氧化指标的影响。选取同一来源经育雏至14日龄的樱桃谷肉鸭320羽,随机分成2个处理组,每个处理组4个重复,每个重复40羽(公母各半),重复之间初始体重接近(P>0.05)。对照组饲喂基础日粮,试验组在基础日粮中添加150mg/kg康华安,试验期27d。研究康华安对樱桃谷肉鸭日增重、平均日采食量、料重比和血清抗氧化指标的影响。试验结果表明,与对照组比较,试验组的日增重显著提高(P<0.05),平均日采食量虽有所升高但差异不显著(P>0.05),料重比显著降低(P<0.05),成活率无显著差异(P>0.05);试验组可显著提高血清中超氧化物歧化酶和谷胱甘肽过氧化物酶活性(P<0.05)。由此可见,饲粮中添加150mg/kg植物提取物饲料添加剂康华安能提高樱桃谷肉鸭生长性能和血清抗氧化功能。     

重组蜂毒素对黄羽肉鸡生长性能等指标的影响

本研究旨在得出添加重组蜂毒素对黄羽肉鸡生长性能、血清中抗氧化指标以及肠道形态的影响。试验选用体重相近1日龄黄羽肉鸡240羽,随机分为3组(每组4个重复,每个重复20羽,公母各占1/2),三个处理组分别为:饲喂基础日粮空白对照组(NC组);饲喂基础日粮+500 mg/kg土霉素钙组(AN组);饲喂基础日粮+300 mg/kg重组蜂毒素组(AP组),试验周期63 d。分别于试验的第1、21、42、63 d进行体重称量和样品采集。结果表明,与NC组相比,三个阶段AP组均具有提高黄羽肉鸡体重(BW)和平均日增重(ADG)的趋势。21 d,AP组丙二醛(MDA)含量显著低于NC组(P<0.05),过氧化物酶(CAT)活性显著高于NC组和AN组(P<0.05);63 d,AP组和AN组的总抗氧化能力(T-AOC)活性显著高于NC组(P<0.05)。与N C组比,42 d AP组十二指肠绒隐比(VH/CD)、回肠绒毛高度(VH)显著提高(P<0.05)。综上,饲料中添加300 mg/kg重组蜂毒素具有提高黄羽肉鸡生长性能的趋势,改善十二指肠形态结构,提高血清抗氧化能力,是一种...     

不同抗氧化剂和添加水平对肉仔鸡生产性能和抗氧化性影响的研究

为了研究不同抗氧化剂产品和添加水平对肉仔鸡生产性能和抗氧化性能的影响,本研究选用1日龄爱拔益加(AA)肉仔鸡96只,随机分为3个处理,每个处理4个重复,每个重复8只鸡。对照组(CTR)饲喂不添加任何抗氧化剂的基础日粮;SQM6组饲喂基础日粮+48mg/kgSQM6;SQMax组饲喂基础日粮+80mg/kgSQMax。记录肉仔鸡的日均采食量和平均日增重,并于28日龄时,随机在每个重复中选取1只鸡进行翅静脉采血,测定血清抗氧化指标。研究结果表明:与CTR相比,肉仔鸡日粮中添加抗氧化剂有改善饲料转化率的趋势(P>0.05);添加SQM6显著提高了血清中超氧化物歧化酶(SOD)的活性(P<0.05),并显著降低了丙二醛(MDA)的含量(P<0.05);日粮中添加SQMax显著提高了肉仔鸡血清超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性(P<0.05)。以上结果表明,肉仔鸡日粮中添加抗氧化剂SQM6和SQMax能够提高血清中超氧化物歧化酶和谷胱甘肽过氧化物酶活性,降低丙二醛含量,改善肉仔鸡机体抗氧化功能。     

日粮中添加植物精油对肉仔鸡生长性能、免疫及抗氧化功能的影响

试验探究肉仔鸡日粮中不同水平的植物精油(EO)对肉仔鸡生长性能,免疫及抗氧化功能的影响。试验选取2 000羽1日龄、健康的南宁良凤肉仔鸡,根据单因素随机试验分为5组,每组10重复,每个重复40羽肉仔鸡。对照组肉仔鸡饲喂基础日粮,EO1组肉仔鸡饲喂基础日粮+100 mg/kg EO,EO2组肉仔鸡饲喂基础日粮+200 mg/kg EO,EO3组肉仔鸡饲喂基础日粮+300 mg/kg EO,EO4组肉仔鸡饲喂基础日粮+400 mg/kg EO。试验周期63 d。结果显示,200和300 mg/kg EO组肉仔鸡末重显著高于对照组(P<0.05),200和300 mg/kg EO组肉仔鸡平均日增重显著高于对照组(P<0.05)。200、300和400 mg/kg EO组肉仔鸡胸腺指数显著高于对照组(P<0.05),200 mg/kg EO组肉仔鸡脾脏指数显著高于对照组(P<0.05),100、200、300和400 mg/kg EO组肉仔鸡血清IgM含量显著高于对照组(P<0.05)。100、200、300和400 mg/kg EO组肉仔鸡血清IgG含量显著高于对照组(P<0.05)。200和300 mg/kg EO组肉仔鸡血清总抗氧化能力显著高于对照组(P<0.05),200、300和400 mg/kg EO组肉仔鸡血清超氧化物歧化酶活性显著高于对照组(P<0.05)。研究表明,在肉仔鸡日粮添加一定量的植物精油可能够提高其生长性能、增强机体免疫力、改善机体抗氧化功能,最适添加量为200 mg/kg。     

植物提取物对育肥猪生长性能、胴体性状、猪肉品质及抗氧化能力的影响

本试验旨在研究植物提取物对育肥猪生长性能、胴体性状、肉品质及猪肉抗氧化能力的影响。选用20头体重相近[(83.75±5.83 kg)]的PIC猪,随机分为对照组(基础日粮)和试验组(基础日粮中额外添加0.04%植物提取物),每个处理5个重复,每个重复2头猪。结果表明,两组间育肥猪采食量、日增重、料肉比和胴体性状差异不显著(P>0.05)。与对照组相比,试验组肉色a*45min值显著提高(P<0.05),L*96 h值极显著降低(P<0.01);4℃下储存0、3 d和7 d猪肉,试验组肉样中丙二醛(MDA)的含量显著降低,超氧化物歧化酶(SOD)活性显著提高(P<0.05)。因此,饲粮中添加植物提取物有利于储存中猪肉品质的改善。     

不同植物提取物替代抗生素对黄羽肉鸡生长性能、抗氧化功能及胫部着色的影响

试验旨在研究不同植物提取物替代抗生素对黄羽肉鸡生长性能、抗氧化功能及胫部着色的影响。试验选取体重相近、健康1日龄黄羽肉鸡公雏鸡2 400只,随机分为6组,每组4个重复,每个重复100只肉雏鸡。对照组(NC)饲喂基础日粮,试验组肉鸡分别饲喂在基础日粮中添加抗生素(ANT)、水解单宁酸(TA)、博落回提取物(MCE)、山花黄芩提取物(SMF)及止痢草提取物(OEO)的试验日粮,试验为期79 d。结果表明,与NC组相比,日粮添加TA显著降低1～35日龄肉鸡料重比(FCR),提高35日龄肉鸡血清过氧化氢酶(CAT)活性(P0.05);日粮添加MCE和SMF显著降低1～35日龄肉鸡平均日采食量(ADFI)、平均日增重(ADG)及FCR(P0.05),对后期和全期生产性能则无显著影响(P0.05);日粮添加OEO显著降低1～35日龄肉鸡ADG,显著降低1～35日龄和1～79日龄肉鸡ADFI和FCR(P0.05),且OEO组各阶段FCR与ANT组相比差异均不显著(P0.05),OEO组肉鸡79日龄胫部黄度值较NC组显著降低(P0.05)。结果提示,在试验条件下,日粮中添加抗生素或不同植物提取物对黄羽肉鸡均没有明显促生长作用,但对FCR具有一定的改善作用。     

Effect of vitamin A and/or E on plasma enzymatic antioxidant systems and total antioxidant capacity of broiler chickens challenged with carbon tetrachloride

This study was conducted to investigate the effect of vitamin A and E supplementation on the antioxidant defences of broiler chickens against carbon tetrachloride (CCl(4))-induced oxidative stress at 4 weeks of age. Superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities as well as total antioxidant (TAO) level were analysed before and after CCl(4) challenge. Day-old Lohman broiler chickens (n = 144) were randomly assigned to six factorially arranged dietary treatments consisting of vitamin A [1.35 (control) or +20 mg/kg] and vitamin E [20 (control), +40 or +60 mg/kg]. The background of vitamins A and E in the basal diet was 4500 IU (1.35 mg) and 30 IU (20 mg) respectively. At 4 weeks of age, eight chickens from each treatment were bled before interperitoneal injection with 1 ml of CCl(4) (mixed with olive oil in a ratio of 1:1) and bled again 24 h post-injection. Vitamin E supplementation decreased (p < 0.05) the activity of both SOD and GPX and showed a tendency (p = 0.07) for TAO reduction. CCl(4) attenuated SOD and GPX activities as well as TAO level. The decrease was profound (p < 0.05) in chickens fed the basal diet as well as those fed basal diet supplemented with 20 mg vitamin A. TAO levels behaved similarly when chickens were challenged with CCl(4). After CCl(4) injection, SOD activities of all experimental groups were equivalent. The presence of vitamin A decreased (p < 0.05) plasma GPX activity in chickens fed the basal diet supplemented with 40 mg/kg of vitamin E. Results of this experiment suggested that vitamin E supplementation elevated antioxidant enzyme activities while vitamin A supplementation attenuated this effect. Vitamin E supplementation improved the total reducing power by maintaining comparable levels of TAO upon CCl(4) challenge. Further experiments need to be carried out to investigate the role of vitamin A in oxidative stress and to evaluate the lipid peroxidation products.     

黄连提取物对高饲养密度下肉鸡生长性能、血清生化指标及肠道微生物的影响

文章旨在研究高密度饲养条件下肉鸡日粮添加黄连提取物对其生长性能、血清生化指标及肠道微生物的影响。试验将640只平均体重为（42.12±0.16）g的肉鸡随机分为4组（T1～T4）,每组4个重复,每个重复40只。T1组肉鸡在高密度（20/m2）下饲喂基础日粮,T2组肉鸡在正常饲养密度（10只/m2）下饲喂基础日粮,T3组肉鸡在高饲养密度下饲喂基础日粮+20 mg/kg黄连提取物,T4组在正常饲养密度（10只/m2）饲喂基础日粮+20 mg/kg黄连提取物。在为期42 d的饲养试验结束后分析相关指标。结果：T4组22～42 d肉鸡平均日增重、22～42 d和1～42 d采食量最高（P＜0.05）,而T1组1～42 d肉鸡平均日增重和采食量最低（P＜0.05）。T1组肉鸡法氏囊重量分别较T2～T4组显著降低了18.53%、17.42%和18.89%（P＜0.05）。T4组肉鸡血清SOD和T-AOC活性最高（P＜0.05）,但血清丙二醛含量较T1组显著降低了29.04%（P＜0.05）。T1组肉鸡回肠大肠杆菌数量最高,分别较其他组显著提高了7.22%、6.93%和8.10%（P＜0.05）,但T1组肉鸡回肠乳酸杆菌数量较其他组显著降低了14.21%、15.74%和17.62%（P＜0.05）。T4组肉鸡回肠双歧杆菌数量较T1组显著提高了5.41%（P＜0.05）。结论：在高饲养密度条件下肉鸡日粮中添加20 mg/kg黄连提取物可以改善肉鸡生长性能和肠道有益菌数量,提高血清抗氧化指标,降低氧化应激。 [关键词]黄连提取物|饲养密度|肉鸡|生长性能|肠道微生物|血清生化     

Effect of lemon verbena powder and vitamin C on performance and immunity of heat‐stressed broilers

An experiment was conducted to investigate the effect of lemon verbena powder and vitamin C on performance and immunity of broilers under heat stress. The experiment was carried out with a total of 160‐day‐old male Ross 308 broiler chickens in a completely randomized design. From 25 days of age, the birds were assigned to four diets including control diet and treatment diets which were supplemented with 2 levels of lemon verbena (0.5% and 1.0%) and one level of vitamin C (250 mg/kg) in 16‐floor pens with 10 chickens each and reared to 42 days of age. To induce chronic heat stress, birds were exposed to an ambient temperature of 35 ± 2 °C for 8 h daily (from 09:00 AM until 17:00 PM) between 25 and 42 days of age. At the end of experiment, one chick/pen was randomly selected, and the performance and blood parameters were evaluated. Dietary supplementation of 1.0% lemon verbena increased (p < 0.05) average weight gain and feed intake by 5.81% and 3.29%, and reduced feed conversion ratio by 2.59% respectively compared to control group. Birds fed diets containing 1.0% lemon verbena had significantly higher relative weight of bursa of fabricius and breast (p < 0.05). LDL decreased by 15.85% and 17.57%, for birds fed 0.5% and 1.0% lemon verbena respectively. The ratio of heterophyl to lymphocyte was reduced (p < 0.05) by 20.68% via significant decrease in heterophyl by 15.55% and significant increase in lymphocyte by 4.51% in birds fed lemon verbena at the rate of 1.0% compared to those fed the control diet. 1.0% lemon verbena and vitamin C elevated (p = 0.0005) the level of glutathione peroxidase by 51.81% and 27.90%, respectively. In conclusion, lemon verbena and vitamin C improved some performance data and blood metabolites which somehow suppressed the negative effects of heat stress.     

Effects of dietary Forsythia suspensa extract supplementation to lactating sows and nursery pigs on post-weaning performance,antioxidant capacity,nutrient digestibility,immunoglobulins, and intestinal health

The aim of this study was to determine the effect of dietary Forsythia suspensa extract (FSE) supplementation to lactating sows and nursery pigs on post-weaning performance, antioxidant capacity, immunoglobulins, and intestinal health. Based on backfat, body weight (BW), and parity, 24 gestating sows (Landrace × Yorkshire) with average parity of 3.38 ± 0.61 and BW of 234 ± 6.81 kg were allotted into two dietary treatments (control vs. 100 mg/kg FSE) with 12 sows per treatment from day 107 of gestation to day 21 of lactation. After weaning, based on the initial BW and source litter, 192 nursery pigs (Duroc × [Landrace × Yorkshire], average BW of 6.98 ± 0.32 kg, weaned at day 21) were allotted into four dietary treatments with eight replicate pens per treatment, six pigs per pen for a 4-wk study. The treatments included the following: 1) CC (sows and their piglets both fed control diet); 2) CF (sows fed control diet and their piglets fed FSE diet [containing 100 mg/kg FSE]); 3) FC (sows fed FSE diet and their piglets fed control diet); and 4) FF (sows and their piglets both fed FSE diet). The MIXED procedures of SAS for a split-plot arrangement with sow diet as the whole plot and nursery diet as split plot were used to analyze the data. After weaning, piglets from FSE-fed sows had improved (P < 0.05) average daily gain and feed efficiency, and lower (P < 0.05) diarrhea rate in overall (day 1 to 28) compared with those from sows fed control diet. Piglets from FSE-fed sows also had higher (P < 0.05) contents of immunoglobulin G (IgG), growth hormone, superoxide dismutase (SOD), total antioxidant capacity in serum, villus height in ileum, and villus height to crypt depth ratio in jejunum, as well as lower (P < 0.05) content of malondialdehyde (MDA) in serum and crypt depth in ileum compared with those from sows fed control diet. Piglets fed FSE during nursery had increased (P < 0.05) concentrations of IgG, SOD, and catalase, and decreased (P < 0.05) MDA and tumor nuclear factor-α levels in serum compared with those fed control diet during nursery. Piglets from FC group had increased (P < 0.05) protein expression of occludin in jejunal mucosa and relative abundance of Lactobacillus on genus level in colon compared with those from CC group. In conclusion, for the performance and intestinal health, diets supplemented with FSE during lactation phase seemed more efficient to alleviate weaning stress than the nursery phase. In terms of the antioxidant status and immunoglobulins, FSE supplemented in both phases were efficient for nursery pigs.     

Dietary hydrolysed yeast cell wall extract is comparable to antibiotics in the control of subclinical necrotic enteritis in broiler chickens

ABSTRACT

1. The aim of this study was to examine the effect of yeast cell wall (YCW) on performance and physiological responses of broiler chickens under subclinical necrotic enteritis challenge.

2. Six treatments in a 2 × 3 factorial arrangement (non-challenged or challenged plus no supplement, YCW or antibiotics (AB)) was used. Each treatment was replicated eight times with 12 birds per replicate. The treatments included: (1) Positive control (PC; no additive, not challenged); (2) Negative control (NC; no additive, with challenge); (3) YCWN = yeast cell wall (2.0 g/kg diet, not challenged; (4) YCWC = yeast cell wall (2.0 g/kg diet, challenged); (5) ABN = zinc bacitracin 50 ppm + Salinomycin 60 ppm, not challenged); (6) ABC = zinc bacitracin 50 ppm + Salinomycin 60 ppm, challenged).

3. Eimeria challenge at 9 d of age did not affect feed intake (FI), body weight gain (BWG), FCR or liveability at 10 d. The BWG and FCR at 10 d were greater (P < 0.05) in birds fed YCW or AB (AB) diets relative to the PC or NC groups. On 24 and 35 d, FI, BWG, FCR and flock uniformity (28 d) were greater (P < 0.05) in the challenged groups fed YCW or AB diets compared to NC group.

4. Supplementation with YCW ameliorated the negative effects of NE on liver, spleen and bursa weight of birds.

5. Necrotic enteritis challenge decreased (P < 0.05) caecal Lactobacillus and Bifidobacterium spp. counts, and increased ileum lesion score and caecal Clostridium perfirngens counts. This was reversed by the addition of either YCW or AB.

6. Supplementation with YCW and AB resulted to a greater (P < 0.05) dressing percentage and meat yield (35 d).

7. The results indicated that YCW plays a vital role in improving the physiological response and performance of broiler chickens under subclinical necrotic enteritis challenge.     

Effects of excess vitamin D3 and cage density on the incidence of leg abnormalities in broiler chickens

A 2 X 2 factorial experiment was designed to investigate the effects of excess vitamin D3 and cage density on the incidence and severity of leg abnormalities in broiler chickens. One hundred eighty 1-day-old broiler chicks were randomly divided into densities of either 10 (680 cm2/chick) or 20 (340 cm2/chick) per cage and fed a diet containing 22% protein and 2879 kcal/kg metabolizable energy formulated to meet National Research Council requirements. Two levels of vitamin D3 were incorporated to supply either 400 ICU or 4000 ICU/kg feed. High density and excess vitamin D3 resulted in a significant (P less than 0.05) increase in the incidence of twisted leg. Differences in incidence could not be explained through differences in body weight or feed consumption. However, broilers fed the excess vitamin D3 consumed more feed but gained less body weight, suggesting that metabolic stress may have been involved. High density appeared to increase the severity of the disorders, whereas excess vitamin D3 had no effect on severity.     

Comparative efficacy of a phytogenic feed additive and an antibiotic growth promoter on production performance,caecal microbial population and humoral immune response of broiler chickens inoculated with enteric pathogens

The aim of this work was to compare the efficacy of a commercially available phytogenic feed additive(PFA) and an antibiotic growth promoter, which was bacitracin methylene disalicylate(BMD), on performance, nutrient retention, caecal colonization of bacteria and humoral immune responses against Newcastle disease in broiler chickens challenged orally with Salmonella enteritidis and Escherichia coli.One-day-old male Cobb 400 broiler chicks(n = 120) were fed with 1) a negative control(NC) diet, which is the basal diet without any added growth promoter, 2) a positive control(PC) diet, the basal diet supplemented with BMD, 500 mg/kg and 3) a diet supplemented with PFA(150 mg/kg) for 39 days and the birds were inoculated with S. enteritidis and E. coli on d 28. Supplementation of PFA improved body weight, feed conversion ratio, retention of N and crude fiber, increased fecal moisture content and decreased digesta transit time as compared with the NC and PC groups(P 0.01). Both the PC and the PFA was found to be equally effective in controlling the surge in numbers of Salmonella and E. coli following oral inoculation of these bacteria as compared with the NC group(P 0.05) at 24 h past inoculation. Caecal content analysis on d 39 indicated lower numbers of Salmonella, E. coli and Clostridium in the PC and PFA groups as compared with the NC group(P 0.05). The number of Lactobacillus in the PFA group was higher than those in the NC and PC groups(P 0.05). Humoral immune response,measured as hemagglutination inhibition titer against Newcastle disease, was better in the PC and PFA groups compared with the NC group(P 0.05) at d 21 but the difference did not last till d 39. The heterophil to lymphocyte ratio was narrower(P 0.001) and alkaline phosphatase activity was higher(P 0.01) in the PFA group as compared with the NC and PC groups on d 39. It was concluded that the PFA, which is animal, environment and consumer friendly, may be used as an effective replacement for common in-feed antibiotics like BMD to enhance broiler performance especially when the birds are exposed to heavy infections on fields.     

γ-氨基丁酸与VC对热应激状态下马岗肉鹅生长性能及血清生化指标的影响

旨在研究γ-氨基丁酸与VC对热应激状态下马岗肉鹅生长性能与血清生化指标的影响。挑取240只45日龄健康的马岗肉鹅,按体重一致原则随机分为3个组,包括对照组（饲喂基础日粮）和2个试验组（在基础日粮中分别添加100 mg/kg γ-氨基丁酸、100 mg/kg的VC）。结果表明：与对照组相比,在基础日粮中添加γ-氨基丁酸、VC均显著提高马岗肉鹅的日均增重（P〈0.05）、日均采食量（P〈0.05）,显著降低马岗肉鹅料重比（P〈0.05）;且同γ-氨基丁酸添加组相比,VC添加组马岗肉鹅的日均增重更加明显（P〈0.05）,料重比显著降低（P〈0.05）。在血清生化指标方面,同对照组相比,基础日粮中添加γ-氨基丁酸、VC均显著降低血清中乳酸脱氢酶（LDH）、谷丙转氨酶（GPT）、谷草转氨酶（GOT）、碱性磷酸酶（AKP）活性及丙二醛（MDA）、尿素氮（BUN）含量（P〈0.05）;显著提高血清总抗氧化能力（T-AOC）和超氧化物歧化酶（SOD）活性、总蛋白（TP）浓度和三碘甲状腺原氨酸（T3）水平（P〈0.05）;而谷胱甘肽过氧化物酶（GSH-Px）活性及四碘甲状腺原氨酸（T4）水平,各组间差异不显著（P〉0.05）。综上提示,饲粮中添加100 mg/kg γ-氨基丁酸、100 mg/kgVC均可提高热应激马岗肉鹅生长性能;提高热应激马岗肉鹅血清SOD、T-AOC活性,减少MDA含量;降低热应激马岗肉鹅血清LDH、GOT、GPT及AKP活性及促进T3的分泌。     

木薯型日粮添加复合酶对肉鸡生长性能、组织器官重量及养分消化的影响

文章旨在评估日粮用木薯粉替代玉米同时补充外源复合酶对肉鸡生长性能、组织器官重量及养分表观消化率的影响。试验选择平均初始体重（44.15±0.76）g的肉鸡576只,随机分为4组,每组4个重复,每个重复36只。试验日粮采用2×2因子设计,即2种原料（玉米和木薯）和酶添加量（0和100?mg/kg复合酶）,其中T1组和T2组分别饲喂玉米、木薯型日粮,T3和T4组分别在T1和T2基础日粮中添加100?mg/kg复合酶,试验为期3周。结果：玉米型日粮组肉鸡末重较木薯型日粮组显著提高6.65%（P＜0.05）,但料重比显著降低2.10%（P＜0.05）。无论日粮类型如何,添加复合酶较未添加组肉鸡料重比显著降低2.10%（P＜0.05）。日粮类型及复合酶对肉鸡平均日增重和料重比的影响具有显著交互作用（P＜0.05）。与T2组相比,T3组肉鸡脾脏相对重量显著提高50%（P＜0.05）。无论日粮是玉米型还是木薯型,补充100?mg/kg复合酶较未补充组淀粉表观消化系数显著提高5.59%（P＜0.05）。结论：在本研究条件下,日粮中添加50%木薯粉完全替代玉米同时补充100?mg/kg复合酶可以改善肉鸡饲料效率,提高淀粉表观消化率。 [关键词]木薯|复合酶|肉鸡|生长性能|养分消化     

平菇菌糠配合日粮饲喂AA肉鸡的效果研究

试验选用1日龄AA肉鸡144只,公母各半,随机分为4组,对照组饲喂基础日粮,试验1组、试验2组和试验3组,分别在基础日粮中添加5.0、10.0 g/kg和20.0 g/kg的平菇菌糠。结果表明,从试验全期看,综合分析生长性能和经济效益两方面的指标,与对照组相比,试验3组的效果最佳,体增重提高5.59%(P>0.05),料肉比降低3.46%(P>0.05),经济效益增加8.05%。