日粮蛋白质水平对肉仔鸡生产性能和免疫机能的影响

用5种蛋白质水平(0￣3周分别为19.44%、20.69%、21.56%、22.43%、23.26%;3～6周对应的为17.62%、18.78%、19.56%、20.34%、21.52%),研究了日粮蛋白质水平对肉仔鸡生产性能和免疫功能的影响。结果表明:日粮蛋白质水平对肉仔鸡增重和免疫功能均有显著影响,蛋白质不足或过量都将使肉鸡生产性能和免疫力下降,蛋白质不足比过量对肉鸡生长和免疫的更为不利。使肉鸡获得最大生产性能和最佳免疫力的蛋白质水平并不一致。本试验中,3周龄前获得最佳生产性能的蛋白质水平为22.43%,获得最佳免疫力的蛋白质水平为20.56%￣21.56%;3￣6周龄时二者基本一致为19.96%。     

High vitamin D3 requirements in broilers for bone quality and prevention of tibial dyschondroplasia and interactions with dietary calcium, available phosphorus and vitamin A

1. Two experiments were carried out to investigate responses in performance and bone compositional and structural characteristics in broilers fed diets containing 4 concentrations of vitamin D3 (5, 20, 125 and 250 microg cholecalciferol/kg) at different concentrations of calcium, available phosphorus and vitamin A. 2. In experiment 1, body weight and tibia breaking strength were maximised at 14d with 250 microg vitamin D3/kg, tibia ash was maximised with 125 microg vitamin D3/kg. A high incidence of tibial dyschondroplasia (TD) was decreased to very low levels with 125 microg vitamin D/kg. 3. At 42d, performance and bone characteristics showed no response to vitamin D3 concentrations above 20 microg/kg. 4. Dietary vitamin A within the range 2-4 to 4.5 mg retinol/kg did not show any interaction with vitamin D3 status at either age. 5. In experiment 2, responses to vitamin D3 were strongly influenced by dietary calcium/available phosphorus. With 13 g calcium and 5 g available phosphorus/kg, performance and bone characteristics responded to vitamin D3 concentrations up to 125 microg/kg but more was needed at less optimal concentrations of calcium and available phosphorus. TD incidence was minimised with 250 microg/kg. 6. This study shows that high dietary concentrations of vitamin D3 can prevent TD. It is concluded that the vitamin D3 requirement of broilers up to 14 d of age at optimal dietary calcium and available phosphorus concentrations may be in the range 35 to 50 microg/kg for cortical bone quality and up to 250 microg/kg for prevention of TD. The vitamin D3 requirement for cortical bone quality after 14 d is not higher than 20 microg/kg. These requirements are much higher than earlier estimates and may be related to higher calcium requirements of modern broiler genotypes. Current regulations limiting maximum vitamin D3 concentrations in broiler starter diets may need to be reviewed.     

日粮维生素A水平对肉鸡组织CaBP基因表达影响的研究

采用完全随机试验设计,将192只8日龄健康AA雄性肉鸡称重后随机分为4个处理组,每处理组6个重复,每个重复8只。在以玉米和豆粕为主要原料的基础日粮中分别添加VA1500,3000,15000和45000U/kg构成试验日粮,试验期5周。应用SYBR GreenI实时定量RT-PCR技术测定肉鸡胫骨、十二指肠组织中CaBP基因表达量,研究不同VA水平对肉鸡组织CaBP基因表达的影响。结果表明:随着日粮VA添加量的增加,十二指肠CaBP基因表达降低,当VA水平增加至15000,45000U/kg时,CaBP基因表达量有降低趋势(P>0.05),其中以45000U/kg添加组的CaBP基因表达量最低。虽然日粮VA水平对肉鸡胫骨组织中CaBP基因的表达影响较小,但当添加水平为45000U/kg时胫骨组织中CaBP基因表达量有降低的趋势。说明过量VA对骨骼代谢影响的机制之一是过量VA降低了与钙、磷代谢有关的CaBP的基因表达,进而影响钙、磷代谢和骨骼发育。     

α-硫辛酸对肉仔鸡肉品质及肌纤维组织特性的影响

本试验研究了α-硫辛酸对肉仔鸡肉品质及肌纤维组织学特性的影响。采用单因子四水平有重复试验设计,将240只1日龄AA肉仔鸡,随机分为4个处理组,每组6个重复,每个重复10只,分别饲喂在玉米-豆粕型基础日粮上添加硫辛酸0、300、600、900mg/kg的日粮,试验期42d。结果表明:硫辛酸显著降低肉仔鸡平均日增重(P0.05)和日采食量(P0.05);硫辛酸显著增加肉仔鸡肌肉a(P0.05),显著降低肌肉b(P0.05)、剪切力(P0.05);硫辛酸显著降低肉仔鸡肌纤维直径(P0.05),并显著增加肌纤维密度(P0.05);硫辛酸组显著增加慢肌(P0.05)、快红肌(P0.05)、肌球蛋白重链基因mRNA的相对表达百分比(P0.05),并显著降低快白肌肌球蛋白重链基因mRNA的相对表达百分比(P0.05)。本试验结果表明,硫辛酸可以通过影响肉仔鸡肌纤维组织特性、肌纤维类型的分布,而改善肉品质。     

矿物质和维生素与蛋壳品质的关系

蛋壳平均含有机物质 4％、碳酸钙 93％、碳酸镁 1％、磷酸钙和磷酸镁 2.8％。蛋壳质量指标包括蛋比重、壳重、蛋壳变形值、蛋壳厚度、蛋壳抗裂强度及单位表面积的壳重等。无论种蛋还是商品蛋，每年因蛋壳质量而引起的损失相当大。营养是影响蛋壳品质的重要因素，本文将着重阐述营养因素中矿物质和维生素与蛋壳品质的关系。 1矿物质 1.1钙 　　日粮钙的供应水平是影响蛋壳质量的决定因素，它决定蛋壳的脆性。成年母鸡每日维持需摄入钙 0.17g，产一枚蛋需钙 2.0g～ 2.2g，而产蛋前半期钙的吸收率为 55％～ 60％，产蛋后期减至 40％，故每产一…     

天然维生素E对肉仔鸡生产性能、肉品质和抗氧化性能的影响

本试验研究天然维生素E对肉仔鸡生产性能、肉品质和抗氧化性能的影响,并时其与化学合成维生素E的效果进行比较.选择480只1日龄健康罗斯308肉仔鸡,随机分为4个处理,每个处理8个重复,每个重复15只鸡,分别饲喂基础日粮(未添加维生素E)中添加天然维生素E 60、120 mg/kg和180 mg/kg以及添加化工合成维生素E 60 mg/kg的试验日粮,试验期42 d.结果表明,添加天然维生素E的各试验组与化工合成维生素E组相比,肉仔鸡全期的平均日增重、平均日采食量和饲料转化率均无显著差异(P>0.05);对肉品质的测定结果中,肌肉pH值、肉色、嫩度以及保水性也无显著影响(P>O.05);对血清谷胱甘肽过氧化物酶(GSH-Px)的影响无显著差异(P>O.05).化工合成维生素E组的丙二醛(MDA)含量极显著高于各天然维生素E组(P0.05),表明天然维生素E组提高了机体的抗氧化能力.     

大豆寡糖对肉仔鸡生长性能的影响

在玉米-大豆浓缩蛋白型低寡糖基础日粮中分别添加0%、0．5%、1．00％或2．00％的大豆寡糖（水苏糖含量为83．7％）,研究了不同添加量大豆寡糖对肉仔鸡生长性能的影响。选用192只1日龄AA肉公鸡,随机分成4个处理组,每个处理设6个笼（重复）,每笼8只鸡。结果表明：大豆寡糖对肉仔鸡生长性能的影响存在剂量反应关系,低剂量表现为促进作用,高剂量则表现为抑制作用;而且生长前期剂量反应程度强于生长后期。添加0．50％大豆寡糖,使1～21日龄生长阶段肉仔鸡的ADG比对照组显著提高了6．16％（P〈0．05）;使22～42日龄、1～42日龄的ADG和1～21日龄、22～42日龄、1～42日龄的ADFI有增加的趋势,但差异不显著（P〉0．05）;添加1．00％大豆寡糖,使22～42日龄、1～42日龄肉仔鸡的ADG和22～42日龄、1～42日龄的ADFI及F／G有增加的趋势,使1～21日龄的ADG和ADFI有降低的趋势,但差异不显著（P〉0．05）;添加2．00％大豆寡糖,使1～21日龄、1～42日龄的ADG显著降低了11．13％和5．75％（P〈0．05）,1～21日龄的F/G显著增加了8．67%（P〈0．05）;22～42日龄的ADG和1～21日龄、22～42日龄、1～42日龄的ADFI有下降的趋势,22～42日龄、1～42日龄的F／G有增加的趋势,但差异不显著（P〉0．05）。     

燃料乙醇DDGS对肉仔鸡生产性能、肉品质及胫骨质量的影响

分析燃料乙醇DDGS营养成分及毒素含量,研究此种DDGS对肉仔鸡生产性能、肉品质及骨骼质量的影响。试验选用240只1日龄科宝艾维茵48肉仔鸡,随机分成4组,每组6个重复。对照组饲喂基础日粮,1～21日龄阶段,试验Ⅰ、Ⅱ、Ⅲ组饲喂含有10%燃料乙醇的DDGS日粮;22～35日龄和36～49日龄两个阶段,试验Ⅰ、Ⅱ、Ⅲ组分别饲喂含有10%、20%和30%燃料乙醇的DDGS日粮。结果表明:DDGS显著降低1～21日龄肉仔鸡采食量(P<0.05);DDGS显著增加肉仔鸡腿肌黄度(P<0.05);DDGS显著增加肉仔鸡骨矿物含量(P<0.05)、胫骨长度(P<0.05)及胫骨重量(P<0.05)。DDGS具有改善胫骨质量的作用。     

不同配比油脂对肉鸡脂类代谢的影响

以肉鸡为动物模型,探讨了日粮中添加不同配比油脂后对其脂肪代谢的影响。648只1日龄AA肉仔鸡,随机分为6组,每组6个重复,每个重复18只鸡,试验期为42 d。CON组为对照组(饲喂基础日粮),SO组为正对照组(日粮中添加豆油),LO组为负对照组(日粮中添加猪油),COP、COC、COV组分别在日粮中添加以棕榈油为主的配比油脂、以椰子油为主的配比油脂、多种植物油配比的油脂。结果表明:42 d,各组腹脂重、皮下脂肪厚度与肌间脂肪厚度、胸肌含脂率、腿肌含脂率均无显著性差异(P>0.05);SO、COP组总甘油三酯含量低于COV组(P<0.05);COP组血清低密度脂蛋白胆固醇含量低于LO组(P<0.01)与CON组(P<0.05);COP组血清高密度脂蛋白胆固醇与低密度脂蛋白胆固醇含量的比值高于LO、COC、COV组(P<0.01),SO组显著提高(P<0.05);SO组肉鸡血清中总脂酶活性高于CON组(P<0.05),肝脏中COP、COC、COV组脂蛋白脂酶、肝脂酶与总脂酶活性都显著提高(P<0.01或P<0.05)。结论:配比油脂组与豆油组在不影响脂肪沉积的情况下,改善了肉仔鸡的体脂分布,且对脂质代谢具有很好的调节作用,其中豆油组与以棕榈油为主的配比油脂组效果较好。     

Effects of dietary supplements of selenium, vitamin E or combinations of the two on antibody responses of broilers

1. The effects of selenium and vitamin E supplementation on some immune parameters were investigated in broilers. 2. Broiler chicks were fed on maize-soybean diets with different concentrations of vitamin E (0-200 mg/kg) and selenium (0-0.2 mg/kg diet) either alone or in combinations from 1 to 42 d of age. 3. Chicks were immunised against Newcastle disease virus (NDV) vaccine at 21 d of age and haemagglutination inhibition (HI) titres were determined after 10 d. 4. Chicks receiving supplements of 200 mg vitamin E/kg and 0.2 mg selenium/kg produced significantly higher HI antibody titres. This was associated with an increased serum concentration of total immunoglobulins and circulatory immune complexes. 5. The chicks given 200 mg vitamin E/kg and 0.2 mg selenium/kg had significantly heavier spleen and bursa. 6. These results suggested that vitamin E and selenium have synergistic effects on immune responses.     

Effects of dietary supplementation with vitamin C or vitamin E on cardiac lipid peroxidation and growth performance in broilers at risk of developing ascites syndrome

OBJECTIVE: To assess effects of high dietary amounts of vitamin C or vitamin E and oxidative stress on the heart and growth performance of broilers maintained at an altitude of 2,200 m above sea level. ANIMALS: 360 chicks (1-day-old broilers). PROCEDURE: Birds were randomly assigned to 3 groups (120 chicks/group). Each group of birds was fed a specific diet (control group, basal diet containing 12 mg of vitamin E (DL-alpha-tocopherol acetate)/kg of feed without additional ascorbic acid; vitamin E group, basal diet supplemented with 75 mg of vitamin E/kg of feed; and vitamin C group, basal diet supplemented with 400 mg of ascorbic acid/kg of feed) throughout the entire 7 weeks of the study. Feed consumption and body weight of chicks were recorded on a weekly basis. Nine randomly selected birds from each group were euthanatized each week. Remaining birds were euthanatized at the end of the study. Samples of cardiac tissues were obtained to measure thiobarbituric acid reactive substances (TBARS), an indicator of oxidative stress. RESULTS: Vitamin E-supplemented diets resulted in better growth performance, lower rates of feed conversion, and lower TBARS content. Vitamin C-supplemented diets resulted in lower feed consumption and lower rates of feed conversion. When used separately, neither of the vitamins had any effect on mortality attributable to ascites syndrome. CONCLUSION AND CLINICAL RELEVANCE: It is recommended that diets supplemented with vitamin C, vitamin E, or both be fed to broilers maintained at an altitude of 2,200 m above sea level to improve growth performance.     

硒代甲硫氨酸对肉仔鸡肉品质和抗氧化性能的影响

试验采用单因子随机化设计,将400只AA肉仔鸡随机分为5个组,每个组设4个重复,每个重复20只鸡。第1组为对照组,饲喂玉米-豆粕型基础日粮,并添加亚硒酸钠0.30 mg/kg;第2~5组为试验组,在基础日粮的基础上,分别添加0.15、0.30、0.45、0.60 mg/kg的硒代甲硫氨酸。通过42 d的饲养试验和测试,综合日增重、采食量和料重比3项生长性能指标,当硒代甲硫氨酸添加量为0.30 mg/kg时肉仔鸡生长性能最佳,且与对照组差异显著(P0.05);与0.30 mg/kg无机组相比,相同剂量的硒代甲硫氨酸在改善肉鸡的屠宰性能方面,可显著提高半净率、腿肌率(P0.05),对胴体率、全净率、胸肌率也有改善作用(P0.05),对改善肉品的滴水损失、嫩度和肉色作用显著(P0.05),但对屠宰24 h后胸肌pH值差异不显著(P0.05);硒代甲硫氨酸添加浓度为0.15 mg/kg、0.30 mg/kg时,对提高肉仔鸡机体抗氧化效应显著(P0.05)。综合各项指标,对于1~42日龄肉仔鸡最适的硒代甲硫氨酸添加量为0.30 mg/kg。     

海带渣对肉鸡代谢率影响的研究

试验选用36只肉鸡,分3组,选用套测法和强饲法相结合,在肉鸡基础日粮中添加不同水平的海带渣,测定肉鸡对海带渣主要养分的表观代谢率。结果表明:海带渣的表观代谢能值为11.02MJ/kg,能量、蛋白质、干物质的表观代谢率分别为80.29%、63.77%、77.20%。     

植酸酶对肉鸡生长性能及饲粮养分利用率的影响

饲养试验选用1日龄的良凤花鸡600羽,随机分为4组(每组设3个重复,每个重复50羽),A组为对照组,饲喂玉米-豆粕型基础饲粮,B、C、D组的饲粮为分别以300、500、700 U/kg的植酸酶取代基础饲粮中的30%、50%、70%的磷酸氢钙。结果表明:0～4周龄,与对照组相比,C和D组平均日增重(ADG)分别极显著提高6.29%(P<0.01)和8.27%(P<0.01);平均料重比(F/G),组间差异不显著(P>0.05)。5～8周龄,与对照组相比,B、C和D组的ADG分别有所提高,F/G有所下降,但组间差异不显著(P>0.05)。B、C、D组鸡血清钙、磷、白蛋白、总蛋白、球蛋白含量随着植酸酶添加量的增加呈上升趋势,但差异不显著(P>0.05);血清碱性磷酸酶活性随着植酸酶的添加而呈降低趋势,但差异不显著(P>0.05)。消化代谢试验结果表明,添加不同水平的植酸酶替代饲粮不同比例的磷酸氢钙,肉鸡饲粮干物质、粗蛋白、粗脂肪、粗纤维、粗灰分、钙和能量的表观代谢率虽然比对照组有所改善,但差异不显著(P>0.05);而磷的表观吸收率分别比对照组显著提高了25.39%～32.48%(P<0.01)。     

Functional microRNA screening for dietary vitamin E regulation of abdominal fat deposition in broilers

ABSTRACT

1. Functional microRNA (miRNA) screening for abdominal fat tissue with different dietary vitamin E (VE) levels was performed to reveal miRNAs, genes and metabolic pathways involved in abdominal fat deposition in broilers.

2. A total of 240, one-day-old healthy female chicks were randomly allocated into five dietary treatments containing either 0, 20, 50, 75 or 100 IU DL-α-tocopherol acetate. The sequencing of miRNAs from abdominal fat tissues was performed. The target genes of miRNAs were predicted and enrichment analysis for these genes was performed. Diets supplemented with 50 IU VE significantly diminished abdominal fat deposition in broilers at day 35 of age.

3. A total of 29 miRNAs were differentially expressed between control and 50 IU VE treatment. Ten of the 23 target genes were enriched in four signalling pathways: tight junction, SNARE interactions in vesicular transport, regulation of autophagy and proteasome.

4. This study identified miRNA, target genes and pathways in dietary VE treatment for broilers, providing new insights into the miRNA regulation of abdominal fat deposition in broilers.     

茶多酚对高酒糟日粮肉鸡生产性能和抗氧化特性的影响

本研究旨在评估添加茶多酚对高酒糟(distillers dried grain with solubles DDGS)日粮肉鸡生产性能和抗氧化特性的影响。将400只21日龄肉鸡随机分为5个处理,每个处理4个重复,每个重复20只。正对照组为玉米-豆粕型日粮,负对照组为玉米-豆粕-DDGS型日粮(15%DDGS),处理组分别在负对照日粮中添加100、300、500 mg/kg茶多酚。结果表明,与正对照组相比,后期日粮中添加15%DDGS对肉鸡生产性能无显著影响(P>0.05),但血液的GSH-Px降低8.31%(P<0.01),胸腿肉T-AOC含量降低,腿肉MDA值显著升高(P<0.05)。添加茶多酚提高了血液的T-AOC和GSH-Px活性(P<0.05)。随着茶多酚添加剂量的升高,T-AOC和GSH-Px有升高的趋势,但各水平组之间差异不显著;茶多酚添加300 mg/kg以上能显著降低胸腿肌MDA值(P<0.05),提高T-AOC含量,改善肉质的抗氧化特性。本研究结果表明,在肉鸡高DDGS日粮中添加茶多酚可以改善肉鸡机体及肉质的抗氧化特性。     

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。     

Effects of dietary tryptophan and stocking density on the performance,meat quality,and metabolic status of broilers

Background:Highly automated cage-rearing systems are becoming increasingly popular in China.However,a high stocking density can cause oxidative stress and decrease broiler performance.The tryptophan(TRP) derivative5-hydroxytryptophan(5-HT) has been shown to preserve membrane fluidity in birds suffering from oxidative stress.Therefore,this experiment was conducted to determine the effects of dietary TRP supplementation on performance,breast meat quality and oxidative stress in broilers reared in cages with a high or low stocking density.Methods:Female Arbor Acres broilers(25-d-old,n=144) were randomly allocated to 1 of 4 treatments.The birds were fed a diet based on corn,soybean meal,cottonseed meal and corn gluten meal containing either 0.18 or 0.27%TRP and were housed with stocking densities of 11 or 15.4 birds/m2 in a 2 × 2 factorial experiment.Broiler performance was evaluated from d 25 to 42.Eight birds from each treatment were slaughtered on d 42 and plasma and breast muscle samples were collected to measure biochemical indices.Results:A higher stocking density tended to be associated with reduced weight gain(P0.10),and significantly increased plasma glutamic-pyruvic transaminase(GPT) activity(P0.001).Increased dietary TRP significantly reduced the activities of lactic dehydrogenase and GPT while increasing total cholesterol in the plasma(P0.01),reducing drip loss of breast muscle(P0.10) and improving feed efficiency(P0.10).Conclusions:An increase in dietary TRP,1.5-fold higher than the standard supplementation level,can alleviate oxidative stress as well as improve welfare and feed efficiency in broilers reared in cages with a high stocking density.     

饲料中添加维生素E对不同养殖密度鲤鱼生产性能的影响

以建鲤为研究对象,采用2×3双因子试验设计,在基础饲料中分别添加0、62.5、187.5mg/kg维生素E,分别在两个养殖密度(15g/L和60g/L)下进行饲喂,探讨饲料中添加不同水平维生素E对不同养殖密度鲤鱼生产性能的影响。试验期为8周。结果表明:(1)养殖密度对鲤鱼的生长、摄食率和重量变异系数具有显著影响(P0.05)。高密度各组的特定生长率和摄食率均显著低于低密度组(P0.05),但是高密度组重量变异系数显著高于低密度组(P0.05)。(2)维生素E显著影响特定生长率(P0.05),对摄食率和重量变异系数无显著影响(P0.05)。同一养殖密度下,维生素E对低密度各组的生长无显著影响(P0.05);在高密度下,维生素E组的生长显著高于对照组。(3)维生素E和养殖密度的交互作用对鲤鱼的生长、饲料系数和重量变异系数影响显著(P0.05)。可见,在本试验条件下,随着鲤鱼养殖密度的增加,应适当增加维生素E的添加量来调控其摄食,进而促进生长和降低个体分化。     

Effects of dietary calcium, phosphorus, calcium: phosphorus ratio and vitamin K on performance, bone strength and blood clotting status of pigs

Three factorial experiments were conducted to evaluate the effects of various Ca:P ratios (1:1, 2:1 and 3:1) in diets having deficient (.3%), adequate (.6%) and excess (.9%) levels of dietary P on rate and efficiency of gain and bone strength of 192 pigs from 18 to 40 kg BW. A corn-soybean meal diet fortified with minerals and vitamins (but not vitamin K) was fed. Levels of Ca and P were achieved by adjusting the amounts of dicalcium phosphate and ground limestone in the diet. The corn was free of detectable mycotoxins. A hemorrhagic condition occurred in Exp. 1 in pigs fed the higher dietary Ca levels; all eight of the pigs fed 2.7% dietary Ca died of internal hemorrhage within the initial 28 d of the experiment. Vitamin K (5 mg menadione [as menadione dimethylpyrimidinole bisulfite]/kg) was added to half of the diets of the remaining animals and the experiment was continued for an additional 14 d. Prothrombin and whole blood clotting times were increased (P less than .01) in pigs fed high Ca without vitamin K but were normal in pigs fed high Ca with added vitamin K. Similar trends in clotting times occurred in a second experiment. A third experiment was conducted to determine whether the addition of vitamin K could reverse the hemorrhagic condition induced by feeding high dietary Ca for 28 d. As in the other two experiments, clotting times were increased (P less than .01) in pigs fed high Ca and no vitamin K. Addition of vitamin K after 28 d resulted in a return to basal prothrombin values by d 50. In regard to the original objectives, increasing the Ca:P ratio from 1:1 to 2:1 or 3:1 tended to reduce rate and efficiency of gain at all levels of P. Increasing the Ca:P ratio to 2:1 resulted in increased bone strength only when P was at or above the dietary requirement.