不同能量、蛋白水平对育雏期(0～2月龄)鸵鸟生产性能的影响

为了研究不同能量、蛋白水平及其互作效应对鸵鸟育雏期生长性能的影响,试验按照二因素三水平,将育雏期(0～2月龄)鸵鸟日粮(精料)代谢能分为3个水平(分别为10.30,11.30,12.30MJ/kg),蛋白分为3个水平(分别为18%、20%、22%),进行排列组合后得到9组日粮。选用同一批次、1日龄、体重相近的幼鸵鸟405只,随机分为9组,每组3个重复,每个重复15只(不分公母),进行为期53d的饲养试验。结果表明:能量组和蛋白组对雏鸟日增重影响不显著(P0.05);能量与蛋白互作对日增重影响差异显著(P0.05);日增重随着能量、蛋白水平的升高而升高。能量组和蛋白组对雏鸟日采食量、料重比影响极显著(P0.01);能量与蛋白互作对日采食量、料重比影响显著(P0.05);日采食量和料重比随着能量、蛋白水平的升高而降低。高能高蛋白组平均日增重最高、平均日采食量最低、料重比最小。     

低蛋白平衡氨基酸日粮对9～16周龄杂交系宁都三黄鸡生长性能的影响

本研究旨在探讨蛋能比保持一定的情况下,低蛋白补充前三种限制性氨基酸日粮对9～16周龄杂交宁都三黄鸡生长性能的影响.试验选取160羽平均体重为612.5g的9周龄健康杂交系宁都三黄母鸡,随机分为4个处理,每个处理4重复,每个重复10羽鸡.处理I(对照组)日粮参照我国黄羽肉鸡饲养标准(2004)进行配制,其代谢能为13206.8kJ/kg、蛋白质为17.0％(蛋白质/代谢能=51.6g/MJ).处理Ⅱ、Ⅲ、Ⅳ(试验组)日粮蛋能比保持不变,粗蛋白分别设计为16.0％、15.0％、14.0％.四组日粮均补充了前三种限制性氨基酸——蛋氨酸、赖氨酸和苏氨酸,使三黄鸡满足对其的需要.结果表明:(1)在蛋能比保持不变的情况下,日粮蛋白质由17.0％降至15.0％时,9～16周龄杂交系宁都三黄鸡日采食量变化不显著,但日增重有下降趋势,料重比呈提高趋势.(2)日粮蛋白质由降低幅度达3个百分点时,尽管补充了三种限制性氨基酸——蛋氨酸、赖氨酸和苏氨酸,但杂交系宁都三黄鸡的日增重和采食量显著降低,料重比由4.4显著升高至4.8.由此可知,在补充前三种限制性氨基酸的情况下,日粮粗蛋白降低的幅度仍不应大于2％.     

不同品种和能量水平对鸡生产性能影响的比较研究

为了探讨不同品种和能量水平对鸡生产性能的影响。选用1d杂交鸡(罗曼蛋鸡×白羽肉鸡)、白羽商品肉鸡、海兰(w58)和琅琊鸡各162只(,每个品种分高、中、低三个能量处理,每个处理9个重复,每个重复6只。在9周的试验期内,自由采食、饮水,测定采食量和体重,计算日增重和料重比。结果表明:四个品种鸡在0~9周龄以内,体重和采食量分别呈现线性和二次增长趋势(P0.05)。本研究日粮代谢能水平范围内(0~3周:12.20~13.36MJ/kg;4~6周:12.34~13.18 MJ/kg;7~9周:12.57~13.36MJ/kg),没有改变各个品种的生长速度(P0.05),但是低能量水平增加了采食量和料重比,四个品种鸡日采食量、日增重和料重比均差异极显著(P0.0001)。品种和能量水平之间采食量具有明显的交互作用(P0.05)。     

日粮类型、能量水平和木聚糖酶对肉鸡生长性能的影响

试验采用2×2×2因子设计,共8个处理,每个处理6个重复,每个重复20只肉鸡,研究日粮类型、能量水平和木聚糖酶对肉鸡生产性能的影响.试验结果:饲粮类型对肉鸡前期料肉比影响不显著(P＞0.05),极显著影响肉鸡各阶段日增重和日采食量(P＜0.01),对后期和全期的料肉比也有极显著影响(P＜0.01).能量水平显著影响后期和全期的料肉比(P＜0.05),显著影响前期日增重(P＜0.05).木聚糖酶显著(P＜0.05)或极显著(P＜0.01)影响肉鸡各阶段的料肉比和日增重,但对采食量没有显著影响(P＞0.05).饲粮类型和能量水平对后期料肉比的影响具有极显著的互作效应(P＜0.01),对全期料肉比的影响具有显著的互作效应(P＜0.05);饲粮类型和木聚糖酶对前期、后期和全期日增重的影响具有显著的交互效应(P＜0.05);能量水平和木聚糖酶对前期日采食量的影响具有极显著的交互效应(P＜0.01);饲粮类型、能量水平和木聚糖酶对后期的料肉比、日采食量和全期的料肉比、日采食量的影响具有显著的交互效应(P＜0.05).试验结果表明,玉米型饲粮组肉鸡生长性能优于小麦组;高能水平组肉鸡生长性能优于低能组,加酶组肉鸡生产性能优于不加酶组.     

日粮蛋白水平对13~18周龄略阳乌鸡生长性能、屠体性能和血清生化指标的影响

本试验旨在研究日粮蛋白质水平对13¹8周龄略阳乌鸡生长性能、屠体性能和血清生化指标的影响,以确定其适宜的蛋白质需要量。选取600只85日龄略阳乌鸡,将其随机分为5个处理,每个处理6个重复,每个重复20只鸡(公母各半)。各处理组分别饲喂代谢能相同、蛋白质含量不同的日粮。代谢能水平均为12.34 MJ/kg,蛋白水平分别为12.39%、14.20%、16.60%、18.06%和20.15%。饲养期间以重复为单位记录试验鸡的周喂料量,每3周以重复为单位记录试验鸡空腹体重(禁食12 h后)。以此计算试验鸡的平均日增重、日采食量及料重比。并于18周龄末各重复分别选取接近相应处理组平均体重的鸡2只(公母各1只),屠宰,进行屠体性能及血清生化指标的测定。结果表明:蛋白质水平对1318周龄略阳乌鸡生长性能、屠体性能和血清生化指标的影响,以确定其适宜的蛋白质需要量。选取600只85日龄略阳乌鸡,将其随机分为5个处理,每个处理6个重复,每个重复20只鸡(公母各半)。各处理组分别饲喂代谢能相同、蛋白质含量不同的日粮。代谢能水平均为12.34 MJ/kg,蛋白水平分别为12.39%、14.20%、16.60%、18.06%和20.15%。饲养期间以重复为单位记录试验鸡的周喂料量,每3周以重复为单位记录试验鸡空腹体重(禁食12 h后)。以此计算试验鸡的平均日增重、日采食量及料重比。并于18周龄末各重复分别选取接近相应处理组平均体重的鸡2只(公母各1只),屠宰,进行屠体性能及血清生化指标的测定。结果表明:蛋白质水平对13¹8周龄略阳乌鸡公鸡平均日增重未产生显著影响(P>0.05);其平均日采食量和料重比随日粮蛋白质水平的升高呈现显著下降的趋势(P<0.05)。蛋白质水平对略阳乌鸡母鸡平均日增重和料重比未产生显著影响(P>0.05),但对平均日采食量及血清尿酸含量有显著影响(P<0.05)。在本试验条件下,当日粮能量水平为12.34 MJ/kg时,基于日粮蛋白质水平对生长性能、屠体性能以及各血清生化指标影响的综合评估,1318周龄略阳乌鸡公鸡平均日增重未产生显著影响(P>0.05);其平均日采食量和料重比随日粮蛋白质水平的升高呈现显著下降的趋势(P<0.05)。蛋白质水平对略阳乌鸡母鸡平均日增重和料重比未产生显著影响(P>0.05),但对平均日采食量及血清尿酸含量有显著影响(P<0.05)。在本试验条件下,当日粮能量水平为12.34 MJ/kg时,基于日粮蛋白质水平对生长性能、屠体性能以及各血清生化指标影响的综合评估,13¹8周龄略阳乌鸡公鸡和母鸡适宜的蛋白需要量均为16.60%18周龄略阳乌鸡公鸡和母鸡适宜的蛋白需要量均为16.60%¹8.06%。     

不同能量与蛋白质水平对生长前期北京鸭生产性能的影响

采用5×2因子设计试验,将560只1日龄北京鸭z系雏公鸭随机分为10个组,每组8个重复,每重复7只,研究日粮能量、蛋白质水平对0～3周龄肉鸭生产性能的影响.试验日粮的代谢能(ME)设12.75、12.12、11.45、10.87、10.24 MJ/kg 5个水平,粗蛋白质(CP)设20.5%、17.5%两个水平.结果表明:(1)能量水平对体重、日增重、腹脂重及腹脂率均呈显著正相关(P<0.05),与日采食量及料重比呈显著负相关(P<0.01);蛋白质水平对降低腹脂率有显著影响(P<0.05),胸肌、腿肌重及其占体重比率都不受能量和蛋白质水平的影响:能量与蛋白质水平的交互作用显著影响21日龄北京鸭体重、日增重及料重比.(2)采用折线模型以料重比及采食量为衡量指标对高蛋白质水平下能量需要量进行估测得出,在20.5%蛋白质水平下,要获得最佳料重比及最低采食量.能量水平分别为12.60MJ/kg和12.56 MJ/kg.     

日粮蛋白质水平对0～5周龄白羽肉杂鸡生长性能的影响

试验选用1日龄白羽肉杂公雏540羽,平均分成3个处理,每个处理设3个重复,每个重复为60羽,用3种不同的处理日粮,蛋白水平分别为：16%、18%和20%;代谢能水平为12.55 MJ/kg,进行为期5周的饲养试验。试验结果表明：日粮蛋白质水平对白羽肉杂公鸡日增重、料重比有极显著影响（P〈0.01）。日粮蛋白质水平对白羽肉杂公鸡采食量影响不显著,随日粮蛋白质水平升高,采食量有下降趋势。以最佳日增重及料重比为衡量指标,0～5周龄白羽肉杂鸡日粮适宜的蛋白质为20%,此时平均日增重23.80 g/d、料重比1.68：1,均明显优于其他处理。     

复合微生态制剂对苏牧白鹅雏鹅生长性能的试验研究

试验研究复合微生态制剂对雏鹅生长性能的影响。采用单因素随机设计,将160只1日龄健康苏牧白鹅仔鹅,随机分为4个处理,每个处理4个重复,每个重复10只,公母各半。0-3周龄雏鹅饲喂两种不同营养水平的饲料,观察其对雏鹅日增重、饲料报酬的影响。结果表明：雏鹅日增重、饲料转化率复合微生态制剂组显著高于不添加组。随着复合微生态制剂添加量的增加,肉鹅的日增重和日采食量均上升的趋势,料重比呈下降后的趋势,其中试验3组的日增重与采食量最高,但与对照组差异显著,与试验1组、试验2组差异显著（P〈0.05）;试验1组与试验2组差异不显著（P〉0.05）;料重比的变化趋势与平均日增重相同。     

日粮粗蛋白质和支链氨基酸水平对肉仔鸡生长性能和肌肉产量的影响

文章旨在研究日粮不同水平的粗蛋白质和支链氨基酸对1～42 d肉鸡生长性能和肉产量的影响。试验选择健康、体重为(60.23±1.08)g的肉仔鸡576只,随机分为4组,每组3个重复,每个重复48只鸡。日粮采用玉米-豆粕型日粮,各组1～21 d肉鸡日粮粗蛋白质水平分别为22.4%、24.9%、23.5%和22.5%,缬氨酸水平分别为0.90%、1.05%、1.05%和1.05%,异亮氨酸水平分别为0.83%、0.95%、0.90%和0.90%,赖氨酸、苏氨酸和含硫氨基酸水平保持一致;22～42 d日粮粗蛋白质水平分别为18.5%、20%、19.5%和18.5%,异亮氨酸水平分别为0.65%、0.75%、0.70%和0.70%,赖氨酸、苏氨酸、缬氨酸和含硫氨基酸水平保持一致。结果显示:处理1组较其他三组显著降低了1～21 d肉鸡日增重(P 0.05),处理2组较处理4组显著降低了日采食量(P 0.05),处理2组料重比表现为最低,显著低于其他三组(P 0.05)。处理4组较处理1组显著提高了22～42 d日增重(P 0.05),较处理2、3组显著提高了日采食量(P 0.05),处理2组较处理1组显著降低了料重比(P 0.05)。处理4组较处理1组显著提高了1～42 d日增重(P 0.05),较处理1、2、3组显著提高了日采食量(P 0.05),处理2组料重比显著低于处理1组和处理4组(P 0.05)。结果提示:日粮添加缬氨酸和异亮氨酸对肉鸡生长性能和肌肉产量的影响与通过原料氨基酸含量达到同等水平缬氨酸和异亮氨酸水平的结果一致。     

不同日粮能量水平对肉仔鸡生产性能和屠宰性能的影响

为了研究不同能量水平日粮对21～45日龄艾维茵肉仔鸡生产性能和屠宰性能的影响,试验选择21日龄150只艾维茵肉鸡,随机分成3组,每组5个重复,每个重复10只鸡,在相同蛋白质水平下(19.50%),试验Ⅰ组、Ⅱ组和Ⅲ组肉仔鸡分别用12.50 MJ/kg、12.90 MJ/kg和13.30 MJ/kg的能量水平日粮饲喂,预试期为3 d,正试期为21 d,检测日增重、日采食量、料重比、胴体重、腹脂率、全净膛率、胸肌率以及腿肌率。结果表明:试验Ⅱ组和试验Ⅲ组的平均日增重、日采食量均显著高于试验Ⅰ组(P0.05),试验Ⅱ组和试验Ⅲ组间平均日增重、日采食量均差异不显著(P0.05),各组间料重比差异显著(P0.05);试验Ⅱ组和试验Ⅲ组的胴体重、腹脂率显著高于试验Ⅰ组(P0.05),试验Ⅱ组和试验Ⅲ组间胴体重、腹脂率差异不显著(P0.05),各组间全净膛率、胸肌率、腿肌率均差异不显著(P0.05)。说明日粮能量水平为12.90 MJ/kg时,肉鸡的生产性能和胴体性能表现较好。     

多菌种复合益生素对三黄鸡的生产性能以及肠道主要菌群的影响

研究多菌种复合菌益生素对三黄鸡的生产性能和肠道主要菌群的影响。试验选用1560只1日龄的广西岑溪三黄肉仔鸡,随机分成2组,每组780只。对照组饲喂基础日粮,试验组日粮由基础日粮加0.1%的益生素组成。饲养时间为6周。试验结果表明:全期试验组的平均日增重比对照组高12.58%(P<0.01),料重比比对照组低9.23%(P<0.05);试验结束时,雏鸡空肠和盲肠大肠杆菌数量分别比对照组低27.61%(P<0.05)和25.57%(P<0.05),乳酸菌数量分别比对照组高16.12%(P>0.05)和11.28%(P>0.05)。     

日粮能量、蛋白质水平对22~42日龄肉鸡WOD168公鸡生长与屠宰性能的影响

为研究22~42日龄肉鸡WOD168公鸡适宜的能量、蛋白质水平,以1 350只22日龄健康的肉鸡WOD168公鸡为试验对象,采用2×3因子设计,研究代谢能水平(ME分别为12.98、13.19 MJ/kg)、粗蛋白水平(CP分别为17.5%、18.5%、19.5%)及其交互作用对鸡生长性能与屠宰性能的影响。结果显示:CP水平为17.5%时42日龄体重显著降低(P<0.01);采食量、料肉比、营养摄入量等均表现出ME、CP的交互作用(P<0.05);屠体率随日粮能量水平提高而降低(P=0.057),而翅膀相对重随蛋白水平提高而提高(P=0.091)。研究提示,22~42日龄肉鸡WOD168公鸡在ME为13.19 MJ/kg、CP为19.5%时可获得最佳生长性能,而ME为12.98 MJ/kg、CP为17.5%时可获得较低料肉比及最佳屠宰性能。     

日粮代谢能和赖氨酸水平对AA肉鸡生长性能和屠宰性能的影响

为了研究日粮不同代谢能和赖氨酸水平对AA肉鸡生长性能和屠宰性能的影响,试验选用160只1日龄AA公雏,随机分为5个处理,每个处理32个重复,每重复1只鸡,实行单笼饲养。试验采用2因子(代谢能和赖氨酸)×2水平(低于和高于对照组)随机区组设计,设1个对照组(代谢能参照NRC,1994),2个代谢能水平分别为12.97、13.81MJ/kg;2个赖氨酸水平0～3周龄分别为1.0%、1.2%,4～6周龄分别为0.9%、1.1%,对照组代谢能水平0～6周龄为13.39MJ/kg,赖氨酸水平0～3周龄为1.1%,4～6周龄为1.0%。42日龄屠宰,试验结果表明:①日粮代谢能水平从12.97MJ/kg提高到13.81MJ/kg,肉鸡平均体重增加12.67%,饲料转化率升高7%(P<0.01);日粮赖氨酸水平提高20%,体重显著增加12.38%(P<0.05),饲料转化率升高3.84%(P<0.01);日粮代谢能和赖氨酸对饲料转化率有显著的互作效应(P<0.05);②随着代谢能水平的提高,屠体重、全净膛重、胸肌重、腿肌重、腹脂重和腹脂率相应提高,高能组显著高于中、低能组(P<0.05),赖氨酸水平对屠体重、全净膛重、胸肌重和胸肌率产生极显著的影响(P<0.01),与低赖氨酸组相比,高赖氨酸日粮组肉鸡屠体重增加12.33%、全净膛重增加12.62%、胸肌重增加28.53%、胸肌率提高3.11%,代谢能和赖氨酸水平对肉鸡腹脂重有显著的互作效应(P<0.05);③日粮代谢能水平为13.81MJ/kg,赖氨酸水平0～3周龄为1.2%、4～6周龄为1.1%时AA肉鸡获得最佳生产性能和屠宰性能,与实际生产中应用的NRC(1994)代谢能和赖氨酸水平相比,AA肉鸡多赢利1.44元/只。     

Effects of L-carnitine and niacin supplied by drinking water on fattening performance, carcass quality and plasma L-carnitine concentration of broiler chicks.

The present study was initiated to determine whether dietary supplemental L-carnitine and niacin affect growth performance, carcass yield, abdominal fat and plasma L-carnitine concentration of broiler chicks. One-day-old broiler chicks (COB500) were used in the experiment. A two by two factorial arrangement was employed with two levels (0 and 50 mg/l) of supplemental L-carnitine and two levels (0 or 50 mg/l) of supplemental niacin in drinking water as main effects. Body weight gain was significantly improved by L-carnitine, or L-carnitine + niacin supplementation during the first 3 weeks. However, supplemental L-carnitine and niacin did not change body weight gain during the last 3 weeks of the experimental period. Supplemental L-carnitine significantly improved feed intake during the first 3 weeks. Supplemental L-carnitine or niacin did not influence carcass weight, carcass yield and abdominal fat weight. L-carnitine content in the plasma was significantly higher in the groups receiving supplemental L-carnitine and L-carnitine + niacin. It is concluded that dietary supplemental L-carnitine or L-carnitine + niacin could have positive effects on body weight gain and feed intake during the early stages of growing. However, supplemental L-carnitine or L-carnitine + niacin were not of benefit regarding the complete growth period.     

Relative virulences of a drug-resistant and a drug-sensitive strain of Eimeria acervulina, a coccidium of chickens

The virulence of a field strain of the chicken coccidian parasite Eimeria acervulina (Boreham I), dually resistant to the chemically unrelated anticoccidial agents decoquinate and clopidol, was compared with that of a drug-sensitive laboratory strain (Ongar) of the same species. Following a single heavy infection (prevented from recycling), both strains exhibited pathogenic effects typical of their species, viz., pathognomonic lesions, adverse effects on body weight gain and feed conversion ratio (FCR), but no mortality. One week after infection, chicks infected with either strain had a statistically significantly worse weight gain than the uninfected control; the Boreham I strain produced more oocysts, and caused slightly more severe duodenal lesions and poorer FCRs than the Ongar strain (all those effects being non-significant). After 3 weeks, there were no significant differences between any cumulative effects of either strain, nor any differences from the uninfected control. However, from 2 to 3 weeks after infection, chicks infected with either strain had a greater feed consumption and growth rate than uninfected chicks. When chicks reared on solid floors were given lighter infections of either strain, which were allowed subsequently to recycle naturally, there were no consistent reductions in weight gains, but feed consumption was higher than that of uninfected chicks. Whatever, the mode of infection, there were no significant differences between the weights of infected and uninfected chicks after 3 weeks, but the FCR of infected chicks was usually poorer than that of uninfected chicks. The difference between the virulences of the Boreham I and Ongar strains was not greater than that between various drug-resistant strains or between various sensitive strains of several Eimeria species recorded in the literature. It is therefore concluded that there was no difference between the virulences of the two strains of E. acervulina that could be attributed to the drug-resistance of one of them.     

DL-羟基蛋氨酸钙相对于DL-蛋氨酸的生物学效价

试验采用肉仔鸡生产性能和胴体品质指标结合回归模型比较了DL-羟基蛋氨酸钙(DL-MHA-Ca)相对于DL-蛋氨酸(DLM)的生物学效价。选取792只体重相近且健康的AA肉仔鸡,随机分为11个处理,每个处理6个重复。DLM或DL-MHA-Ca按照等摩尔水平(0.03%、0.06%、0.10%、0.15%和0.21%)添加到仅缺乏蛋氨酸的基础日粮中。试验期35 d,分为7~21 d和22~42 d 2个阶段。结果表明:7~21 d和7~42 d,添加蛋氨酸源显著改善了肉仔鸡的体增重、饲料/增重、屠体重、胸肉重、胸肉率、腿肉重和全净膛重(P0.05);在等摩尔基础上,DL-MHA-Ca相对于DLM的生物学效价,7~21 d分别是71%(增重)和66%(饲料/增重);7~42 d则分别为63%(增重)、58%(饲料/增重)、74%(屠体重)、60%(胸肉重)、49%(胸肉率)、71%(腿肉重)和72%(全净膛重)。     

Dietary tryptophan effects on growth and stress responses of male broiler chicks

1. Three experiments were conducted to determine growth of broiler chicks fed on test diets formulated to be deficient or adequate in tryptophan (Trp) using gelatin by-product as a means of generating a Trp deficiency. Growth response estimates of broiler chicks to graduations of Trp were determined by dose-response criteria and regression analyses. Experiments were conducted using broiler chicks from 1 to 20 d of age. 2. Broiler chicks fed Trp-deficient diets had poor body weight gain, feed intake and feed conversion. Recommended total Trp needs were 2.0, 2.1 and 2.2 g/kg for feed intake, body weight gain and feed conversion, respectively. 3. Blood plasma Trp exhibited a sigmoidal trend while blood plasma glucose increased in a linear manner to supplemental Trp. Physiological stress variables measured were unaffected by dietary Trp.     

Studies on reducing the crude protein content of feeds fed to chicks and young hens (laying stock)]

2 rearing trials were carried out on a total of 8550 hybrid chicks (White Leghorn) to investigate in which way food mixtures containing reduced levels of crude protein (supplemented or unsupplemented with amino acids) might influence the growth of chicks and young hens. Decreases from 21.5% to 16.5% in the crude protein content of chicken feed and from 15% to 13% in feeds feed to young hens (greater than 8 weeks of life) did not reduce the live weight of birds at the end of the rearing period to any appreciable extent. No clearly defined differences were found to exist between the different types of feed tested concerning the amount of food and energy consumed per unit of weight gain and the mortality rate among the birds; it was shown, however, that the demand for crude protein per unit of weight gain was clearly reduced in birds reared at the lower crude protein level. For young hens receiving the diet poorer in protein the date when the birds began laying was slightly delayed. Otherwise, no statistically significant differences were found to exist between the young birds fed varying levels of crude protein, concerning the age at 50% laying performance and other parameters that are characteristic of the entire laying period (laying performance, weight of individual eggs, food consumption, mortality, fertilization of hatching eggs, hatchability of eggs). It appears that the feeding of a reduced protein diet to chicks and young hens (laying stock) did not have any detrimental effect on the growth and later laying performance of the birds. Apart from the fact that the demand for protein feeds is considerably reduced during the rearing period the costs of feeding per bird can also be cut down.     

氯丙嗪对肉用仔鸡热应激的影响

１６０只１周龄健康肉用雏鸡随机分成２组，经１周预试后进行试验。对照组和试验组鸡的日粮处理分别为：基础日粮、基础日粮＋０１％氯丙嗪。试验期５周。研究在日粮中添加氯丙嗪对慢性热应激肉用仔鸡生产性能及某些生理生化指标的影响。结果表明：试验组鸡的料肉比比对照组鸡低，增重是对照组鸡的１１７３８％，且试验组鸡的胸肌／体重、腿肌／体重的比值高于对照组鸡，试验组鸡的甲状腺重量高于对照组鸡，Ｔ３／Ｔ４的比值极显著高于对照组鸡，试验组鸡的肾上腺重量小于对照组鸡，血清中皮质醇（Ｃｏｒ）的含量较对照组鸡低。     

Single injection of clenbuterol into newly hatched chicks decreases abdominal fat pad weight in growing broiler chickens

The aim of the current study was to examine the effects of clenbuterol injection into newly hatched chicks on both the abdominal fat pad tissue weight and the skeletal muscle weight during subsequent growth. Twenty‐seven 1‐day‐old chicks were divided into two groups, receiving either a single intraperitoneal (i.p.) injection of clenbuterol (0.1 mg/kg body weight) or phosphate‐buffered saline (PBS). Body weight gain, feed intake and feed conversion ratio were not affected by clenbuterol injection during the 5‐week experimental period, while the abdominal fat pad tissue weight of the clenbuterol‐injected chicks was lower than that of the control chicks at 5 weeks post‐injection. Plasma non‐esterified fatty acid concentrations were significantly increased in the clenbuterol‐injected chicks, while plasma triacylglycerol concentrations did not differ. Additionally, the enzymatic activity of fatty acid synthase was lower in the liver of the clenbuterol‐injected chicks. Conversely, the skeletal muscle weights were not affected by clenbuterol injection. These results suggest that a single clenbuterol injection into 1‐day‐old chicks decreases the abdominal fat pad tissue weight, but may not affect skeletal muscle weights during growth. © 2015 Japanese Society of Animal Science