VE与硒添加水平对0～3周龄肉仔鸡生产性能及免疫指标的影响

本试验采用4×4双因子完全随机设计,设4个硒水平(0.15,0.30,0.45,0.60mg/kg)和4个VE水平(10,15,20,25mg/kg),将1152只1日龄健康爱维茵肉仔鸡,按试验设计随机分成16个处理,每处理4个重复,每个重复18只鸡。试验至第21天结料称重,采血,取肝脏、脾脏、法氏囊等进行样品测定。结果表明:(1)不同VE水平对生产性能、免疫机能均无显著影响;对肝组织硒含量、红细胞中GSH-Px活力影响差异显著;(2)不同硒水平对生产性能、免疫机能、肝组织硒含量、红细胞中GSH-Px活力均有显著影响;(3)VE与硒的互作对生产性能影响差异不显著,对免疫机能、肝组织硒含量、红细胞中GSH-Px活力的影响均差异显著。     

维生素C对热应激状态下肉仔鸡生产性能及维生素C合成能力的影响

选用21日龄AA肉仔鸡240只,研究了热应激（室温32－35℃,相对湿度80％－825）和非应激（室温20－25℃,相对湿度65％－70％）状态下日粮添加维生素C对肉仔鸡生产性能和体内维生素C合成能力的影响。试验结果表明,肉仔鸡在应激状态下血浆维生素C含量降低,日粮补充200mg/kg维生素C可以明显提高血浆维生素C含量。热应激导致肉仔鸡肝脏维生素C合成关键酶－古洛糖酸内酯氧化酶活性明显降低,使维生素C含量。热应激导致肉仔鸡肝脏维生素C合成关键酶－古洛糖酸内酯氧化酶活性明显降低,使维生素C的合成能力减弱,日粮汪厍维生素C可提高应激状态下肉仔鸡肝脏古洛糖酸内酯氧化酶活性,随肉仔鸡日龄的增加,肉仔鸡肝脏古洛糖酸内酯氧化酶活性有上升趋势,表明维生素C合成能力随日龄的增加逐渐提高。     

日粮中添加浓缩大豆磷脂对肉鸡生产性能的影响

选出壳重相近、发育正常的４００只１日龄的爱拔益加（ＡｒｂｏｒＡｃｒｅ）雄性肉仔鸡,随机分为４组,研究近似能量和等蛋白情况下用改性浓缩大豆磷脂（ＳＬ,丙酮不溶物含量为６２％）替代基础日粮（对照组）中豆油的２５％、７５％和１００％对肉仔鸡生产性能和胴体品质的影响。在１周～３周,对照组、２５％ＳＬ、７５％ＳＬ和１００％ＳＬ组改性浓缩大豆磷脂的添加量分别为０％、１％、１５％和２５％,大豆油添加比例分别为２５％、１５％、１％和０％。在４周～６周,４组改性浓缩大豆磷脂的添加量分别为０％、１５％、２５％和３５％,大豆油添加比例分别为３５％、２０％、１％和０％。在第７周,４组改性浓缩大豆磷脂的添加量分别为０％、２％、３５％和４５％,大豆油添加比例分别为４５％、２５％、１％和０％。结果表明,利用改性浓缩大豆磷脂替代肉仔鸡日粮中大豆油的２５％具有较好的饲料转化效率。用改性浓缩大豆磷脂替代肉仔鸡日粮中大豆油的２５％、７５％和１００％,对７周龄体重和饲料转化效率、腿肌比例和胸肌比例无显著影响。用大豆磷脂完全替代肉仔鸡日粮中的大豆油对７周龄体重和饲料转化效率无显著影响,而且有提高屠宰率、降低腹脂、改善肉质的?     

日粮中不同电解质对热应激肉鸡生产性能的影响

为了评价相等电解质平衡值(DEB为250mEq/kg)的三种Na盐(NaHCO3、Na2CO3、Na2SO4)和三种K盐(KHCO3、K2CO3、K2SO4)以及两种DEB为50mEq/kg的氯盐(CaCl2和NH4Cl)对肉鸡生产性能的相对效果,采用324只817肉鸡在周期性热应激环境(最低29.2℃,最高37.9℃)下饲养42d。一种基础日粮和8种试验日粮共计9个处理,每个处理设3个重复(每个重复有12只鸡)。结果显示:除了KHCO3以外的K盐添加组的生产性能较Na盐添加组要低很多。NaHCO3、Na2CO3、Na2SO4和NH4Cl添加组与K2CO3和K2SO4相比,使增重、采食量和饲料利用率增加;同时这些添加组提高了饮水量,从而使体温和死亡率降低。CaCl2添加组的生产性能较低与钙、磷比例失调和血液pH值较低有关。碳酸氢盐添加组比碳酸盐和硫酸盐组生产性能要高。     

不同抗生素对肉鸡生产性能影响的试验

本试验用２４００只“ＡＡ”肉仔鸡随机分为４组,每小组６００只,５次重复,试验Ｉ组用速大肥;试验Ⅱ线用杆菌肽锌;试验Ⅲ组用硫酸粘杆菌素＋杆菌钛锌,并设对照组,饲养期为５３天,出栏各组体重分别为２４１２ｇ,２３０８ｇ,,２３８６ｇ２２６５ｇ经方差分析,试验Ｉ组,试验Ⅲ组与对照组差异极显著（Ｐ〈０．０１）,试验ＩＩ组与对照组差异显著（Ｐ〈０．０５）,各组饲料转化率分别为２．２４５,２．３１２,２３．２７     

在肉仔鸡日粮中添加必需氨基酸和维生素的效果

提高DL-蛋氨酸、L-赖氨酸和维生素水平,探讨对肉鸡生产性能的影响,其做了四顶试验,以下分别叙述.     

大豆磷脂在肉鸡饲料中的应用研究

选用120羽1日龄的AA肉仔鸡,随机分为4组,每组设6个重复,每个重复5羽鸡。研究大豆磷脂替代基础日粮(对照组)中1%、2%、3%的玉米对肉鸡生产性能和胴体品质的影响。结果表明,用大豆磷脂替代日粮中的玉米使肉鸡42日龄增重分别提高了2.1%、4.4%和8.7%;饲料转化率分别提高了3.5%、5.2%和8.1%;饲养成本分别下降了2.3%、3.5%和5.8%;胸肌率分别提高了14.7%、0.9%和-0.49%,腹脂率分别提高了11.06%、20.28%和44.7%。     

大豆肽在肉鸡饲料中的应用研究

试验选用180羽健康AA肉仔鸡,随机分成6个处理组,每个处理6个重复,每个重复5羽。A组为空白对照, B组为添加抗生素（黄霉素5 mg/kg）试验组, C、D、E、F组分别为添加大豆活性肽0.2%、0.4%、0.6%、0.8% （固态,含活性肽40 g/kg）的试验组。试验结果表明,在生产性能上,大豆活性肽可显著提高肉仔鸡日增重和采食量,在提高屠宰率方面也有一定的作用;在经济效益上,大豆活性肽可以降低饲料成本,增加毛利润。因此,大豆活性肽可以有效应用于肉仔鸡生产中,其最适添加量为06%,优于使用抗生素（黄霉素5 mg/kg）。     

大豆磷脂在肉鸡饲料中的应用研究

试验选用120羽0日龄的AA肉仔鸡,随机分为4组,每组设6个重复, 每个重复5羽鸡。研究大豆磷脂替代基础日粮(对照组)中1%、2%、3%的玉米对肉鸡生产性能和胴体品质的影响。结果表明,与对照组相比，用大豆磷脂替代日粮中的玉米使肉鸡42日龄增重分别提高了2.1%、4.4%和8.7%;饲料转化率分别提高了3.5%、5.2%和8.1%;饲养成本分别下降了2.3%、3.5%和5.8%;胸肌率分别提高了14.7%、0.9%和-2.5%,腹脂率分别提高了11.06%、20.28%和44.7%。     

两种铬源对热应激肉鸡抗氧化性能的影响

本试验旨在研究两种铬源对热应激肉鸡抗氧化能力的影响。选择15日龄AA肉仔鸡180只,随机分为3组,1组高温不加铬(对照组),2组高温加酵母铬,3组高温加烟酸铬,铬添加量为3mg/kg,试验期4周(15～42d)。结果表明:日粮中添加3mg/kg铬,显著降低了28d、42d丙二醛和过氧化氢的含量(P0.05),提高了抗超氧阴离子能力、总抗氧化能力及谷胱甘肽过氧化物酶的活性(P0.05),显著提高了28d超氧化物歧化酶活性(P0.05),但对42d超氧化物歧化酶活性无显著影响(P0.05)。因此,热应激状态下,日粮中添加铬可减少脂质过氧化反应、降低过氧化产物生成、提高热应激肉鸡抗氧化能力,但两种铬源之间差异不显著。     

硒和维生素E协同添加对肉鸡肉品质量的影响

近年来，随着人们生活水平的提高，对肉品的品质也要求越来越高。肉品质量主要由肉品的理化性质决定，肉品的化学成分与其营养价值关系密切；肉品的物理指标如颜色、持水性、嫩度和多汁性等直接影响消费者对肉品的接受程度。     

酵母培养物与抗生素对肉仔鸡生长性能及免疫机能影响的研究

用 2 1 0只 1日龄艾维茵肉仔鸡 ,随机分成 7组 ,即 :对照组、 0 1 %、 0 3%、 0 5 %、 0 7%、 0 9%酵母培养物组和抗生素组 (5mg/kg ) ,每组设 3个重复 ,每个重复 1 0只鸡 ,试验期 2 8d,研究不同添加水平的酵母培养物和抗生素对肉仔鸡生长性能和免疫机能的影响。试验结果表明 :0 3%的酵母培养物组日增重、日采食量、饲料转化率 ,较对照组略有提高 ,但差异不显著 (P >0 0 5) ,抗生素组与对照组和酵母培养物组相比差异显著 (P <0 0 5) ;各组之间营养物质代谢率差异不显著 (P >0 0 5) ,酵母培养物组有提高的趋势 ;酵母培养物显著降低大肠杆菌的数量 ,提高双歧杆菌的数量 (P <0 0 5) ,抗生素显著降低了大肠杆菌和双歧杆菌的数量 (P <0 0 5) ;酵母培养物显著提高了肉仔鸡血清IgA、IgG水平(P <0 0 5)和IgM水平 (P >0 0 5)。     

肉仔鸡对胰蛋白酶抑制因子的耐受性研究

给15日龄AA肉仔鸡分别饲喂胰蛋白酶抑制因子(TI)9.01,6.45,3.74,1.80,1.39,0.34g/kg的日粮至35 d.肉仔鸡对饲粮中胰蛋白酶抑制因子的耐受性阈值为3.74g/kg.     

Potential application of Fe-methionine as a feed supplement on improving the quality of broilers breast meat

A total of 250 one-day-old Ross 308 male chicks were used to investigate the effects of Fe-methionine (Fe-met) and iron sulfate (FeSO₄.7H₂O) on performance, mineral concentration, meat quality, and oxidative stability of breast. The feeding experiment was performed with five dietary groups including group I (basal diet [BD] + 80 mg/kg FeSO₄), group II (BD + 60 mg/kg FeSO₄ + 20 mg/kg Fe-met), group III (BD + 40 mg/kg FeSO₄ + 40 mg/kg Fe-met), group IV (BD + 20 mg/kg FeSO₄ + 60 mg/kg Fe-met), and group V (BD + 80 mg/kg Fe-met). The results showed that Fe and Cu content in the breast muscle increased by dietary supplementation of organic and inorganic iron from II to V groups. Dietary groups of II, IV, and V increased L* value and b* value of breast meat. Additionally, redness of breast meat enhanced linearly and quadratically by dietary supplementation of 80 mg/kg Fe as FeSO₄. In addition, dietary supplementation Fe from II to V groups led to a significant increase in pHu at 24-h postmortem while it was negatively correlated with L* value of breast muscle. This study demonstrates that replacing FeSO₄ with Fe-Met could improve breast meat yield of broilers. Although 80 mg of Fe-Met improved the iron content of meat, it showed detrimental effects on the lipid oxidation of breast meat.     

硼对铜中毒肉用乌骨鸡肝铜含量及肝功能的影响

选用560只1日龄肉用乌骨鸡,采用二因子多水平随机化试验设计研究日粮硼对铜中毒肉鸡肝铜及肝功能的影响。分别在玉米-豆粕型基础日粮中(Cu50.9 mg/kg,B10.1 mg/kg)添加549.1、749.1 mg/kg的铜和49.1、109.1 mg/kg的硼。结果表明,硼可在一定程度上抵御高铜对肝细胞的毒害,并减少肉鸡肝铜的蓄积量,说明硼对肉用乌骨鸡铜中毒具保护效应。     

Crop beta-glucanase activity limits the effectiveness of a recombinant cellulase used to supplement a barley-based feed for free-range broilers

1. The supplementation of diets rich in soluble polysaccharides with microbial cellulases and hemicellulases decreases digesta viscosity and promotes broiler performance. 2. In contrast, recent experiments suggest that polysaccharidases are ineffective for improving the nutritive value of pasture biomass used by free-range broilers. However, the feasibility of using cellulases and hemicellulases to improve the utilisation of cereal-based feeds by pastured poultry remains to be established. 3. A study was undertaken to investigate the capacity of a recombinant cellulase from Clostridium thermocellum to improve the nutritive value of a barley-based feed for free-range pastured broilers of the RedBro Cou Nu x RedBro M genotype. 4. The results show that supplementation of a barley-based diet with a recombinant beta-glucanase had no effect on the performance of free-range broilers, foraging in legume-based diets from d 28 to 56. In addition, the results confirm that the lack of effect of the recombinant enzyme in improving the nutritive value of the barley-based feed does not result from enzyme proteolysis or inhibition in the gastrointestinal tract. 5. Significantly, beta-glucanase activity was identified in the crop of non-supplemented animals. The data suggest that endogenous cellulases originated both from the barley-based feed and from the crop microflora. 6. The results presented here suggest that in older birds of slow-growing genotypes associated with free-range production systems, previously unknown sources of beta-glucanases, such as the feed and microbial symbiotic microflora, can affect the effectiveness of exogenous enzymes added to the feed.     

Performance, serum characteristics, carcase traits and lipid metabolism of broilers as affected by supplement of chromium picolinate.

1. This study investigated the effects of dietary supplementation with chromium picolinate on the performance, serum and carcase traits and lipid metabolism of broilers. In trial 1, 120 1-day-old broilers with an equal number of males and females were assigned at random to 4 groups with 3 replicates. Four treatments with dietary supplements of 0 (control), 800, 1600 and 3200 microg/kg of chromium picolinate were used. In trial 2, 6-week-old broilers (20) were used to determine how supplements of 0, 200, 400 and 800 microg/kg chromium in an incubation medium influence their hepatocyte lipogenic capacity and adipocyte lipolysis, in vitro. 2. Dietary supplements of 1600 and 3200 microg/kg chromium in broiler diets significantly increased food consumption (P<0.05); 1600 microg/kg markedly improved weight gain (P<0.05); 1600 and 3200 microg/kg groups showed increased liver lipid content (P<0.05). However, the abdominal fat content tended to decrease in these 2 groups. 3. Dietary supplements of 1600 and 3200 microg/kg of chromium decreased serum glucose and nonesterified fatty acids (NEFA) concentrations while increasing serum phospholipid content (P<0.05). Insulin concentration decreased only in birds receiving 3200 ppb chromium (P<0.05). Serum triacylglycerol (TG) clearance rate in chromium-supplemented groups was markedly enhanced (P<0.05). 4. In addition, chromium supplemented groups had increased serum HDL contents and also reduced serum VLDL and LDL contents (P<0.05). 5. Trial 2 indicated that lipogenesis from [U-14C]glucose by isolated hepatocytes was significantly enhanced by 400 ppb chromium (P<0.05). 6. The results from this study demonstrate that a supplement of 1600 microg/kg of chromium picolinate in the ration influences the growth, carcase, serum traits and lipid metabolism of broilers.     

Twisted legs in broilers

1. The effect of various factors on the incidence of leg abnormalities, with particular reference to twisted leg, in broilers was studied.

2. The incidence of twisted legs was influenced by strain and for males was twice that for females. There was also a higher incidence in cages than on litter with the type of cage floor having an effect: broilers reared on floors of metal wire and perforated sheets had more leg problems than those reared on plastic mats and plastic‐covered wire.

3. Although vitamin and mineral supplementation had no effect on caged broilers, a restriction of metabolisable energy (ME) intake during the first 14 d after hatching halved the frequency of leg abnormalities compared with those fed ad libitum.

4. Studies of cage size and location of water suggested that a lack of exercise increases the incidence of leg abnormalities.