高温蛋鸡日粮添加柠檬酸的效果研究

柠檬酸是一种有效的饲料酸化剂。国内外大量研究表明，柠檬酸可以弥补仔猪胃酸分泌不足，降低胃肠道ｐＨ值，激活消化酶原，改善肠道微生物区系，从而有效预防仔猪下痢，提高日增重；一些试验也证明，柠檬酸可以提高肉鸡增重和蛋鸡产蛋性能，但总体说来柠檬酸在养禽业中应用和研究远不如仔猪业广泛和深入，尤其是在蛋鸡方面的研究报道更少。夏季高温（３０－３５Ｃ）常使鸡处于应激状态，导致饮水量加大，采食量降低，饲料利用率和生产性能下降，严重时可使鸡只死亡。近年的研究认为柠檬酸是养禽业中很有前途的应激保护剂（冷向军，１９９９…     

柠檬酸对蛋鸡生产性能影响的研究

在基础日粮中分别添加 0 .1%、0 .2 %、0 .3%、0 .4%的柠檬酸 ,探讨其对产蛋鸡生产性能的影响。经 60 d试验结果表明 ,以添加 0 .2 %柠檬组效果最好。     

高温季节日粮中添加氯化钾对蛋鸡生产性能的影响

高温季节日粮中添加氯化钾,在一定程度上可以防止鸡的热应激,显著提高产蛋量及蛋重,但对饲料消耗、蛋形指数、比重及软、破蛋率无明显影响。结果表明氯化钾的添加浓度以0.1%为宜。并对其机理做了初步分析。     

日粮中添加柠檬酸对蛋鸡生产性能的影响

柠檬酸作为饲料添加剂是因为柠檬酸能降低饲料的pH值,使胃内pH值下降,从而促进无活性的胃蛋白酶原转化为有活性的胃蛋白酶。胃内酸性增强可减慢胃的排空,延长蛋白质在胃内的停留时间,有利其消化吸收。柠檬酸在降低胃肠道内容物pH值的同时,可作为配位体,与饲料中的矿物质发生螯合作用促进肠道对矿物元素的吸收,柠檬酸作直接     

柠檬酸对蛋鸡生产性能影响的研究

在基础日粮中分别添加０．１５％、０．２５％、０．３５％、０．４５％、０．５５％的柠檬酸，探讨其对蛋鸡生产性能的影响。６０天试验结果表明，以添加０．１５％～０．２５％柠檬酸组效果最好。     

日粮中添加沸石对蛋鸡生产性能的影响

本试验选用本校牧场39周龄体健海兰商品蛋鸡1000只,随机分为五个组Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ,每组设四个重复,试验Ⅰ组为不含沸石的对照组,试验Ⅱ、Ⅲ、Ⅳ、Ⅴ组分别在其日粮中用1%,3%,5%,7%的沸石代替玉米或豆粕,每组200只鸡在同一鸡舍笼养(温度、湿度、光照均满足正常生产需要)。试验结果表明,除第Ⅴ组外,所有试验组的产蛋率分别高于对照组0.02%、3.09%、0.36%,饲料利用率分别提高0.84%、5.42%、2.50%。经统计分析,添加3%、5%沸石的两组产蛋率和料蛋比与对照组相比,差异极显著(P<0.01)。试验结果表明,产蛋鸡日粮中添加3%的沸石,生产性能和经济效益最佳。     

日粮中添加亚麻油对蛋鸡生产性能的影响

日粮中添加１％和３％亚麻油,研究不同剂量亚麻油对蛋鸡生产性能及蛋中脂肪酸含量的影响。结果表明,不同剂量亚麻油对蛋鸡产蛋量及蛋中各部分所占的比例没有影响,但添加亚麻油后蛋中总脂肪酸、ω－３系列多不饱和脂肪酸总量及二十碳五烯酸和二十二碳六烯酸的含量均升高。因此,日粮中添加亚麻油生产的蛋可以做为人类ω－３系列多不饱和脂肪酸的重要来源。     

高温条件下在蛋鸡日粮中添加柠檬酸的效果

高温条件下 ,对315只黄金褐蛋鸡在日粮中添加柠檬酸的效果进行了试验 ,设0 %、0.1 %、0.2 %、0.3 %、0.4 %、0.5 %6个柠檬酸水平和0.3 %菌宝共7个处理组。28d试验结果表明 ,柠檬酸可以减缓蛋鸡热应激 ,提高产蛋率和饲料报酬 ;0.1 %～0.4 %的柠檬酸组与0.3 %的菌宝组效果相当 ;各处理对粪便水分无显著影响。与对照组相比 ,柠檬酸添加组和菌宝组平均产蛋率分别提高9.69 %、8.08 %、8.67 %、8.81 %、2.97 %和8.69 %;饲料报酬分别提高7.60 %,6.46 %、7 98 %、7.98 %、1.90 %和6.84 %;每只鸡每天多收入0.017元、0.011元、0.015元、0.010元、0.00元和0.013元     

日粮中添加植酸酶对商品蛋鸡生产性能的影响

许多研究结果证实,在动物饲料中添加微生物植酸酶可使存在于植物籽实中的植酸分子得以水解,并游离出植酸磷(Nelson等,1968;Simons等,1990),所以在饲料中添加少量的植酸酶,动物就能在很大程度上利用植酸中的磷。simons等(1990)用微生物植酸酶喂肉鸡,结果鸡对饲料中磷的利用率显著提高,特别是对于低磷日粮,磷的利用率可提高60％,粪便中磷的排出量减少约40％,同时提高了肉仔鸡的增重速度和饲料转化率,促进了骨骼的生长。另外对猪(Young等,1993;Dungelhoet等,1994)和火鸡(Qian等,1996)也得     

日粮中添加沸石对蛋鸡生产性能的影响

本试验选用本校牧场39周龄体健海兰商品蛋鸡1000只，随机分为五个组I、Ⅱ、Ⅲ、Ⅳ、Ⅴ，每组设四个重复，试验I组为不含沸石的对照组，试验Ⅱ、Ⅲ、Ⅳ、Ⅴ组分别在其日粮中用1％，3％，5％，7％的沸石代替玉米或豆粕，每组200只鸡在同一鸡舍笼养（温度、湿度、光照均满足正常生产需要）。试验结果表明，除第Ⅴ组外，所有试验组的产蛋率分别高于对照组0．02％、3．09％、0．36％，饲料利用率分别提高0．84％、5．42％、2．50％。经统计分析，添加3％、5％沸石的两组产蛋率和料蛋比与对照组相比，差异极显著（P＜0．01）。试验结果表明，产蛋鸡日粮中添加3％的沸石，生产性能和经济效益最佳。     

Effect of dietary nonphytate phosphorus on laying performance and small intestinal epithelial phosphate transporter expression in Dwarf pink-shell laying hens

This study examined the effects of various levels of dietary nonphytate phosphorus on laying performance and the expression patterns of phosphorus metabolism related genes in Dwarf pink-shell Jaying hens. A total of 405 28-week-old Dwarf pink-shell laying hens were fed the same corn-soybean basal meals but containing 0.20%, 0.25%, 0.30%, 0.35% or 0.40% nonphytate phosphorus. The results showed that feed intake, egg production, and average egg weights were quadratically correlated with dietary nonphytate phosphorus content （P 〈 0.05）, and the highest egg production, feed intake and average egg weights were achieved when dietary nonphytate phosphorus was at 0.3% （P 〈 0.05）. mRNA expression of intestinal sodium phosphorus co-transporter linearly decreased when dietary nonphytate phosphorus increased, mRNA and protein expression of intestinal calbindin and vitamin D receptor correlated quadratically with dietary nonphytate phosphorus, and the highest expression was found when dietary available phosphorus was at 0.2,5% to 0.3%. In conclusion, the ideal phosphorus requirement for Dwarf pink-shell layer hens is estimated to be 0.3% in a corn-soybean diet. With this level of phosphorus supplementation, calbindin and vitamin D receptor reached their highest expression.     

Effects of dietary Crotalaria pallida seeds on the health and performance of laying hens and evaluation of residues in eggs

The effect of three dietary concentrations of Crotalaria pallida (C. pallida) seeds (0, 1, 2, and 3% w/w) of their normal diet were investigated in commercial laying hens during a 35 day feeding trial. All concentrations of C. pallida decreased body weight and feed intake (P < 0.05). Egg mass production and average egg weight were decreased by feeding of ≥2% C. pallida seeds (P < 0.05). All concentrations of C. pallida increased relative lung weight and serum activity of ALT, AST and LDH (P < 0.05); 3% C. pallida seeds decreased liver weight (P < 0.05). Analysis of the C. pallida seeds for dehydropyrrolizidine alkaloid content detected usaramine and its N-oxide at a total alkaloid concentration of 0.18% (dry weight). Usaramine was also detected in the eggs of all hens fed C. pallida seeds.     

饲料中添加蝇蛆和蚯蚓饲喂蛋鸡的效果观察

通过在蛋鸡日粮中分别添加蝇蛆和蚯蚓作为动物蛋白补充料,在饲养管理条件相同的情况下,饲养60d,测定其对产蛋率的影响,结果表明:在日粮中添加10g鲜蛆和10g蚯蚓,试验1、2组分别比对照组多增加产蛋数2480枚和2000枚,比对照组提高产蛋率10%和8%;试验1、2组分别比对照组增加收入1096.00元和848.00元,经济效益十分明显。     

沈阳地区蛋鸡大肠杆菌病流行病学调查及药敏试验

本试验调查沈阳地区28家蛋鸡养殖户及鸡场,样本数量达到15万只蛋鸡,日龄范围从30至500日龄不等,采集了其中50只病鸡的排泄物和内脏样品用于检测和分析。采用鉴别培养基和生化试验对样品进行细菌分离鉴定,再对检出的大肠杆菌进行Ο抗原鉴定。结果表明,在所采集的样品中大肠杆菌检出49例样品为阳性,检出率为98%;鉴定出大肠杆菌36株,定型30株,定型率为83.33%。药敏结果表明,仅恩诺沙星和氟苯尼考对全部采集到的大肠杆菌菌株高敏,其余药物多中敏或轻敏;而传统的青霉素、链霉素多表现为耐药。     

不同硒源对蛋鸡生产性能和硒沉积的影响

文章旨在研究日粮添加不同硒源及不同水平对蛋鸡生产性能和鸡蛋中硒沉积量的影响。试验选择产蛋率一致的海兰褐壳蛋鸡720只,随机分为5组,每组6个重复,每个重复24只鸡。试验共设计5种日粮,对照组饲喂基础日粮(不添加硒),处理组分别在基础日粮中添加2个水平的无机硒(0.4和0.8mg/kg硒,亚硒酸钠)以及2个水平的酵母硒(0.4和0.8mg/kg硒),试验共进行16周。结果发现,无论日粮添加酵母硒还是无机硒,随着硒添加水平的升高,蛋鸡生产性能均无显著影响(P>0.05)。从第9周到试验结束,0.4mg/kg无机硒和0.8mg/kg酵母硒组较对照组和0.8mg/kg无机硒组显著提高了蛋鸡的产蛋率(P<0.05)。试验第9周开始,对照组、0.8mg/kg无机硒组和0.4mg/kg酵母硒组产蛋率显著降低(P<0.05)。随着日粮无机硒或酵母硒添加水平的升高,鸡蛋中硒的沉积量显著线性增加(P<0.05)。从第4周开始到试验结束,无机硒或酵母硒组较对照组均显著提高了鸡蛋中硒含量(P<0.05)。在同一硒添加水平及同一时间下,酵母硒较无机硒显著提高了鸡蛋硒含量(P<0.05),随着试验时间的增加,对照组鸡蛋硒含量显著降低(P<0.05)。因此,在本试验条件下,日粮硒的来源和添加水平直接影响鸡蛋硒沉积量,酵母硒较无机硒显著提高了鸡蛋硒沉积量。日粮中酵母硒的添加量可以达到0.8mg/kg,对蛋鸡生产性能无负面影响。     

Salmonella in Belgian laying hens: an identification of risk factors

Since the 1980s, the prevalence of Salmonella in Belgian poultry layers and broilers has greatly fluctuated with a rise observed in 2003 and a significant decrease in 2005. In order to alleviate the risk at egg consumer level, it is crucial to understand the factors which influence the contamination and the spread of Salmonella in laying hens. To study such determinants we explored the Belgian data from the 2005 baseline study on the prevalence of Salmonella in laying flocks of Gallus gallus in the European Union. The response variables corresponded to presence or absence of Salmonella from dust and faecal samples taken from the environment of a Belgian layer flock. The explanatory variables included: region of Belgium, sampling time (month the flock was sampled), production type (cage or barn and free range), Salmonella vaccination status, flock age and flock size. Analyses of these data were performed using a bivariate logistic regression model assuming independence between the two responses and bivariate generalized estimating equations model, which incorporates the correlation between the two responses on the same flock. The main risk factor that was identified was rearing flocks in cages compared to barns and free-range systems. The results also showed a significant higher risk for Salmonella for a 1 week increase in flocks’ age as well as with a unit increase in the size of the flock.     

Effect of prebiotic fructans and organic acids on mineral retention in laying hens

Abstract

The aim of the study was to evaluate the effect of organic acids and prebiotic fructans added to the layer's diet on balance of calcium, phosphorus, and zinc. The basal experimental diet contained 3.30% Ca and 0.60% P, and was either unsupplemented or supplemented with additives as follows: 0.75% inulin, 0.75% oligofructose; 0.50% short-chain fatty acids (SCFA); 0.25% medium-chain fatty acid (MCFA); 0.30% SCFA+0.20% MCFA; and 0.75% inulin+0.50% SCFA. It was concluded that some additives used in the experiment had a positive effect on the mineral balance in hens. Inulin significantly improved retention of Ca, P, and Zn, SCFA – retention of Ca, SCFA+MCFA – retention of Zn, inulin+SCFA – retention of P and Zn.     

蛋鸡生产过程中两个关键的过渡时期

蛋鸡生产过程中,从育雏期到育成期,随着蛋鸡自身生理特点的变化,饲养管理条件和技术措施需随之改变,这种改变一定要逐步稳妥进行。蛋鸡从育成结束到产蛋开始,各方面也有一个过渡的过程,这一过程中要做的工作较多,是一个比较特殊的时期,有人将17～22周龄称为蛋鸡的预产期,能否平稳度过预产期,有关以后产蛋性能的发挥和蛋鸡的有效利用,实践中应予以重视。     

有机酸和益生元对蛋鸡生产性能和蛋壳质量的影响

文章旨在评估不同钙磷水平日粮中添加有机酸和益生元对蛋鸡产蛋量和蛋壳品质的影响。试验选择504只罗曼褐壳蛋鸡,根据产蛋率一致的原则随机分为14个组,每组36只鸡,采用蛋鸡单笼饲养。试验日粮采用2×7因子设计,即两个钙和磷水平(正常组和低水平组)以及不添加、添加0.8%的菊粉和低聚糖、0.5%挥发性脂肪酸中链脂肪酸、0.25%挥发性脂肪酸+0.25%中链脂肪酸、0.4%菊粉+0.25%中链脂肪酸,试验从26w开始到70w结束。试验结果发现,各处理组对产蛋率、采食量、饲料转化率均无显著影响(P>0.05)。低钙磷日粮显著降低了蛋壳百分率、蛋壳厚度、蛋壳密度和蛋壳强度(P<0.05)。日粮添加益生元和有机酸能显著改善46、58和70w蛋壳质量,其中菊粉和中链脂肪酸对蛋壳质量的改善最为显著(P<0.05)。日粮钙、磷水平与益生元和有机酸对各指标的影响无显著交互作用(P>0.05)。结果表明,日粮添加有机酸可以降低饲料pH,同时益生元可以调控肠道功能,从而对高龄高产蛋鸡蛋壳品质有改善作用。     

免疫不同剂量禽流感疫苗对蛋鸡抗体效价的影响

禽流感作为家禽养殖业的最大威胁,通过科学使用禽流感疫苗进行免疫能够有效预防暴发禽流感疫情。本试验对蛋鸡在相同条件下注射不同剂量的禽流感疫苗,间隔相同时间后采样测定抗体的效价,结果表明:首次免疫的剂量0.3 m L/羽、0.4m L/羽、0.5 mL/羽,一个月后测定的(H5+H7)抗体滴度平均值随着免疫剂量的增加而提高,60日龄加强免疫剂量为0.5 mL/羽、0.7 mL/羽、0.9 mL/羽,一个月及两个月后测定的(H5+H7)抗体滴度平均值均保持在最高水平10。试验表明:首次免疫禽流感疫苗剂量为0.5 m L/羽的抗体效价水平最高,加强免疫的不同剂量均能使抗体效价在较长一段时期保持最高水平。