笼养和栖架养殖模式下鸡蛋品质比较

本研究旨在比较笼养模式和栖架养殖模式对海兰褐蛋鸡鸡蛋品质的影响。试验选择80只13周龄海兰褐蛋鸡,随机分成两组,25只蛋鸡采用笼养模式(笼底面积为500cm2/只)饲养,55只蛋鸡采用栖架养殖模式(网格面积593 cm2/只+栖杆长度16.4 cm/只+沙浴区域面积1.05 m2+产蛋箱面积0.675m2)饲养,在蛋鸡36、42和49周龄时对蛋品质进行测定。结果表明,除36和49周龄鸡蛋蛋黄颜色栖架饲养模式和笼养饲养模式存在显著性差异(P0.05)外,蛋重、蛋形指数、蛋壳强度、蛋壳厚度、蛋壳重、蛋壳颜色、蛋白高度、哈氏单位、蛋黄重、蛋黄比例以及蛋清比例在不同饲养模式下均无显著性差异(P0.05)。     

饲养密度对蛋鸡育雏期生长性能的影响

为研究蛋鸡育雏期不同饲养密度对生长性能的影响,试验以海兰褐蛋鸡为研究对象,选取1 440只雏鸡进行试验,将其分为高密度组、中密度组和低密度组,每组每周末随机选取60只,测量体重、胫长、龙骨长、胸宽。试验期49 d。结果显示:7～49日龄低密度组体重显著高于中密度和高密度组(P0.05),除7日龄外,均为中密度组体重高于高密度组,在28、35和49日龄差异显著(P0.05);7～35日龄低密度组胫长显著高于中密度组和高密度组(P0.05),42日龄和49日龄差异不显著(P0.05)。龙骨长除35日龄外,其余日龄均为低密度组高于中密度和高密度组;胸宽整体表现为低密度组中密度组高密度组的趋势。研究提示:饲养密度对海兰蛋鸡育雏期的生长性能有明显的影响,体重、胫长、龙骨长、胸宽均表现为随饲养密度增加整体呈下降趋势。结合经济效益和生长发育来看,建议饲养密度前5周为20～30只/m~2,6～7周龄为10只/m~2。     

不同饲养密度对地面平养蛋鸡福利状况和生产性能的影响

试验旨在通过研究地面平养模式下不同饲养密度对蛋鸡行为、外观、血液应激指标及生产性能的影响,筛选保证蛋鸡福利状况及生产性能的最大饲养密度,为我国推广地面平养模式蛋鸡福利养殖奠定理论基础。将780只苏禽绿壳蛋鸡按舍内密度分为四组,其中地面平养分为低密度组(6只/m^2)、中密度组(8只/m^2)、高密度组(10只/m^2),笼养组为对照组,每组3个重复。试验期为18~27周龄,蛋鸡行为学数据均采用视频录像收集,在27周龄末进行翅静脉采血和福利外观评价,统计分析24~27周龄生产性能。结果显示:笼养蛋鸡的产蛋率,攻击、刻板等非福利行为均显著高于平养组(P<0.05),脚垫损伤、羽毛评分、应激激素浓度(CORT、ACTH)显著低于平养组(P<0.05)。地面平养各组间,高密度组蛋鸡料蛋比显著高于低、中密度组(P<0.05);低、中密度组蛋鸡行走和休息时间比例均显著高于高密度组(P<0.05);低密度组蛋鸡啄羽行为显著低于高密度组(P<0.05),但与中密度组差异不显著(P>0.05);低、中密度组蛋鸡脚垫损伤、背羽损伤显著低于高密度组(P<0.05);高密度组蛋鸡血清中CORT和ACTH浓度显著低于低、中密度组(P<0.05)。由此可见,平养蛋鸡比笼养蛋鸡行为表现更积极,羽毛覆盖度更好,但应激水平和足部损伤较高、生产性能较低;在试验场地模式下,推荐8只/m2为最佳饲养密度。     

饲养密度对大午金凤商品代蛋雏鸡生长性能、器官指数及血清抗氧化指标的影响

试验以324只1日龄大午金凤商品代蛋雏鸡为试验材料,随机分为三个处理(低密度组、中密度组和高密度组)以探究饲养密度对蛋雏鸡生长性能、器官指数及血清抗氧化性指标的影响,并用Logistics模型拟合雏鸡的生长曲线,以期获得0~6周龄大午金凤适宜的饲养密度。试验分为两阶段(0~2周龄、3~6周龄)。低、中、高饲养密度0~2周龄分别为:107 cm~2/只、83 cm~2/只、68 cm~2/只,3~6周龄分别为:214 cm~2/只、167 cm~2/只、136 cm~2/只。每个处理3个重复。结果显示:0~2周龄时,低密度组蛋雏鸡胫长、体重及平均日增重显著高于高密度组(P0.05);3~6周龄时,低密度组蛋雏鸡平均日采食量、平均日增重显著高于中密度组和高密度组(P0.05);随饲养密度升高,蛋雏鸡体重呈显著下降的趋势(P0.05);低密度组蛋雏鸡小肠总长显著高于高密度组(P0.05);低密度组蛋雏鸡血清CAT的浓度显著低于高密度组(P0.05)。0~6周龄随着饲养密度增大,低、中、高密度组大午金凤体重的拐点周龄分别为3.853、4.002和4.070周龄,胫长的拐点周龄分别为1.391、1.513、1.800周龄。综合蛋雏鸡体重、胫长、平均日采食量、耗料增重比、血清抗氧化指标,推荐大午金凤商品代蛋鸡0~2周龄的饲养密度为83~107 cm~2/只,3~6周龄的饲养密度为167~214 cm~2/只。     

笼养密度对雪山鸡生产性能及盲肠微生物的影响

旨在探索笼养密度对雪山鸡生产性能、肉品质、福利指标及盲肠微生物的影响。本研究选用6周龄体重相近的健康雪山鸡母鸡180只,按单因素试验要求,设置高、中、低3组饲养密度进行后期笼养试验,每笼分别饲养4只、3只及2只,以此作为1个重复,每组20个重复,饲养至上市15周龄,屠宰,测定生产性能、屠宰性能及肉品质,并进行羽毛和步态评分、检测盲肠微生物菌群组成。结果表明：1）从11周龄到上市15周龄,低、中密度组雪山鸡体重显著高于高密度组（P<0.05）,15周龄腹脂重和腹脂率,低密度组显著高于中密度组（P<0.05）,且中密度组显著高于高密度组（P<0.05）,其余屠宰性能指标差异均不显著（P>0.05）。2）中、低密度组鸡只羽毛质量显著好于高密度组（P<0.05）,此外,高、中、低密度组的雪山鸡步态评分差异不显著（P>0.05）。3）雪山鸡盲肠内容物均以Firmicutes（厚壁菌门）、Proteobacteria（变形菌门）、Bacteroidetes（拟杆菌门）的菌群为主。3种饲养密度菌群差异不显著（P>0.05）,但中密度饲养模式下肉鸡盲肠内容物中特有OTUs较少,相对于高密度盲肠微生物区系而言,中、低密度盲肠微生物群落更趋于相近,有些差异菌群可能与体重及腹脂沉积相关,如Blautia菌属等。综合看来,对于雪山鸡而言,考虑采用中密度饲养模式能够获得较好的生产性能。     

饲养方式对蛋鸡免疫水平、肠道菌群及蛋品质的影响

研究不同饲养方式对蛋鸡免疫功能、肠道微生物和蛋品质的影响及相互关系。选取600只16周龄海兰褐商品蛋鸡,随机分为2组,分别进行常规笼养和散养,每组300只,每组3个重复,每个重复100只,于不同周龄对蛋鸡免疫指标、肠道微生物及蛋品质进行检测分析。结果:除24周龄外,散养蛋鸡血液IgA、IgM和IgG含量均高于普通密度笼养蛋鸡;β-内啡肽含量除24周龄外均低于普通笼养鸡;散养方式下蛋鸡盲肠中乳酸杆菌数明显高于笼养方式,且差异显著(P<0.05)或极显著(P<0.01),表明散养鸡整体免疫力和抗病能力高于笼养鸡。笼养鸡的平均蛋重为(60.02±1.75)g,高于散养鸡的平均蛋重(59.43±2.31)g,差异显著(P<0.05);和笼养鸡蛋相比,散养鸡蛋的哈夫单位和蛋黄颜色较高,且差异显著(P<0.05),而蛋白高度相比,散养鸡随周龄逐渐下降,笼养鸡逐渐上升,但2种饲养方式之间差异不显著(P>0.05)。     

复合植物提取物对蛋鸡生产性能、肠道黏膜形态及盲肠菌群结构的影响

本试验旨在研究饲粮中添加不同水平复合植物提取物对蛋鸡生产性能、肠道黏膜形态及盲肠菌群结构的影响。试验选取960只42周龄的健康状态良好且体重、产蛋率相近的海兰灰蛋鸡,随机分为4组,每组5个重复,每个重复48只鸡。对照组饲喂基础饲粮,试验Ⅰ、Ⅱ、Ⅲ组在基础饲粮中分别添加150、300和450 mg/kg复合植物提取物。预试期10 d,正试期56 d。结果显示:1)与对照组相比,饲粮中添加300和450 mg/kg复合植物提取物显著提高了蛋鸡的产蛋率(P0.05)。2)与对照组相比,饲粮中添加300 mg/kg复合植物提取物显著降低了空肠和十二指肠隐窝深度(P0.05),显著增加了十二指肠绒毛高度与隐窝深度的比值(P0.05)。3)在盲肠菌群结构方面,与对照组相比,在门水平上,饲粮中添加300和450 mg/kg复合植物提取物显著提高了拟杆菌门的相对丰度(P0.05),饲粮中添加450 mg/kg复合植物提取物显著降低了厚壁菌门的相对丰度(P0.05);在属水平上,饲粮中添加450 mg/kg复合植物提取物显著提高了拟杆菌属的相对丰度(P0.05),有提高艾克曼菌属相对丰度的趋势(P=0.063)。综上所述,在本试验条件下,饲粮中添加300 mg/kg复合植物提取物可提高蛋鸡的产蛋率,降低空肠和十二指肠隐窝深度,提高十二指肠绒毛高度和隐窝深度,并提高盲肠菌群中拟杆菌门的相对丰度,从而改善蛋鸡的肠道黏膜形态及盲肠菌群结构,提高生产性能。     

日粮添加地衣芽孢杆菌对蛋鸡肠道菌群与形态结构的影响

为探讨日粮中添加地衣芽孢杆菌对蛋鸡肠道菌群与形态结构的影响,选用392日龄健康的海兰灰蛋鸡360只,随机分为4个组,每个组设6个重复,每个重复15只鸡。对照组饲喂基础日粮,试验Ⅰ、Ⅱ、Ⅲ组在基础日粮中分别添加1×109cfu/kg、2×109cfu/kg、3×109cfu/kg的地衣芽孢杆菌。结果表明:日粮中添加3×109cfu/kg地衣芽孢杆菌对平衡肠道菌群、改善肠道形态结构效果明显。     

林下混播草地放养对北京油鸡肉品质及肠道菌群的影响

本试验旨在研究林下“菊苣(Cichorium intybus L.)+多年生黑麦草(Lolium perenne L.)+一年生黑麦草(Lolium multiflorum L.)”混播草地放养对北京油鸡肌肉营养品质及肠道菌群的影响。将体重相近的9周龄北京油鸡母鸡随机分为3组：林下清耕地散养组(养殖密度90只·667 m^-2,CK)、林下混播草地放养组(设置2个养殖密度，即90只·667 m^-2(T1)和120只·667 m^-2(T2)),采用划区轮牧的方式饲养至21周龄。结果表明：与CK组相比，T1和T2组显著提高了胸肌和腿肌的总氨基酸和必需氨基酸含量(P<0.05),T2组还显著提高了腿肌的鲜味氨基酸含量(P<0.05)。此外，T1和T2组显著降低了十二指肠菌群丰富度和多样性(P<0.05),十二指肠菌群中益生菌Lactobacillus相对丰度也得到显著提高(P<0.05),但对回肠和盲肠菌群结构无影响。综上所述，林下混播草地放养显著提升了肌肉氨基酸品质，这可能与十二指肠菌群结构发生改变有关...     

太行鸡和海兰灰蛋雏鸡盲肠主要消化生理特性的比较

本试验旨在比较分析太行鸡与海兰灰蛋鸡盲肠主要消化生理特性及菌群的变化。选择1日龄太行鸡和海兰灰蛋鸡各120只,分为两组,每组设4个重复,每个重复30只,公母各半。分别于1～9、11、13周龄测定盲肠相对长度、相对重量、pH值及其内容物的大肠杆菌、双歧杆菌、乳酸菌数量、纤维素酶活性。结果表明:(1)太行鸡盲肠相对长度和相对重量均高于海兰灰蛋鸡。其中3、4、5、6、7、9、13周龄,太行鸡盲肠相对长度显著高于海兰灰蛋鸡(P0.05);太行鸡盲肠相对重量4周龄时极显著高于海兰灰蛋鸡(P0.01),5、9、13周龄时显著高于海兰灰蛋鸡(P0.05);(2)太行鸡盲肠纤维素酶活性极显著的高于海兰灰蛋鸡(P0.01)。(3)各阶段太行鸡盲肠pH值均低于海兰灰蛋鸡,但差异不显著。(4)太行鸡盲肠大肠杆菌数量低于海兰灰蛋鸡,乳酸菌和双歧杆菌高于海兰灰蛋鸡。4、5、6、8、9周龄时,太行鸡盲肠大肠杆菌显著低于海兰灰蛋鸡(P0.05);太行鸡盲肠乳酸菌6周龄时极显著高于海兰灰蛋鸡(P0.01),3、4周龄时显著高于海兰灰蛋鸡(P0.05);太行鸡的盲肠内双歧杆菌数量,1、2、3、6、11周龄时,极显著高于海兰灰蛋鸡(P0.01),7周龄时显著高于海兰灰蛋鸡(P0.05)。试验结果表明:太行鸡较海兰灰蛋雏鸡的盲肠消化能力强。     

饲养方式对蛋鸡产蛋前期生产性能的影响

试验通过对比舍外散放蛋鸡与舍内笼养蛋鸡在体重、胫长和胫围等方面的差异来研究饲养方式对鸡产蛋前期生产性能的影响。结果表明：散放鸡体重在8、10、12周龄显著低于同周龄笼养鸡;散放鸡胫长在10、12周龄显著低于同周龄笼养鸡;散放鸡胫围在10周龄显著低于同周龄笼养鸡。笼养鸡和散放鸡各周龄的胫长和胫围变异系数均小于10%,均匀度均高于或等于80%。两组蛋鸡各周龄体重的变异系数均小于10%,体重均匀度呈逐级递增状态,6周龄蛋鸡体重均匀度较低,到12周龄时均匀度已达到80%。两组蛋鸡的生产性能各指标均达到海兰褐蛋鸡饲养标准。     

Evaluation of the effects of cage height and stocking density on the behaviour of laying hens in furnished cages

1. Limited information is available on how changes in horizontal and vertical space within enriched or furnished layer cages (as defined by Directive 1999/74/EC) influence hen behaviour. This study evaluated the effects of varying minimum cage heights and space allowances on the behaviour of laying hens housed in furnished cages. It was conducted on two flocks of medium brown hybrid hens housed in furnished cages with access to perches and nest boxes on a semi-commercial scale at ADAS Gleadthorpe. 2. Flock 1 consisted of two layer strains (ISA Brown and Babcock 380), housed at two minimum cage heights (38 and 45 cm) and 5 stocking densities between 609 and 870 cm2/bird, with 12 replicates of each of the 20 strain/cage height/stocking density treatment combinations. Stocking density was varied by varying the number of birds per cage from 10 to 7 in standard full-width cages or housing 7 hens in a narrower cage. As a consequence stocking density, group size and trough width per bird co-varied for 4 out of 5 stocking density treatments. 3. Behaviour of flock 1 was sampled at 33 to 36, 46 and 68 weeks of age. At each age one top-tier, one middle-tier and one bottom-tier cage was sampled for each treatment. 4. Few behavioural differences due to cage treatments were detected. Hens at 870 cm2 had shorter feeding bouts than hens at 609 and 762 cm2. Yawning was more common in the cages with greater cage height. 5. Video recordings of flock 1 examined cage height effects on hens' use of vertical space and provided additional data on stretching and self-maintenance activities. No differences in behaviour between 38 and 45 cm cages were found except that scratching head was more common in cages with greater cage height. 6. Flock 2 consisted of two layer strains (Shaver Brown and Hy-Line Brown), housed at 38 and 45 cm and 609, 762 and 1016 cm2/bird, with 18 replicates of each of the 12 strain/cage height/stocking density treatment combinations. Stocking density was varied by housing 10, 8 or 6 hens in standard full-width cages. Behaviour of flock 2 was sampled at 30, 48, 60 and 67 weeks from video recordings. Three cages per treatment from middle-tiers only were sampled at each age. 7. Hens housed at 609 cm2/hen had the longest mean feeding bout, greater than for hens at 762 cm2/hen but not hens at 1016 cm2/hen. More unsuccessful attempts to reach the feeder and sideways and backwards displacements from the feeder occurred at 762 and 609 cm2/hen than at 1016 cm2/hen. A maximum of 8 hens were observed feeding synchronously. 8. These results suggest that changes in horizontal and vertical space over the ranges we studied had little effect on behaviour other than feeding behaviour. Specifying a minimum useable trough space per hen, rather than calculating feeder space from total length of feeder per cage, irrespective of accessibility, might help avoid crowding at the feeder and associated disturbance of feeding bouts.     

甜菜碱预防蛋鸡脂肪肝出血综合征的研究

本试验旨在研究甜菜碱对蛋鸡脂肪肝出血综合征的预防效果。选用300日龄海蓝褐蛋鸡120只,随机分为3组,每组4个重复,每个重复10只,在自由采食、饮水和光照16 h的条件下,分别饲喂正常日粮（代谢能11.30 MJ/kg,粗蛋白质17.20%）、高能量低蛋白质日粮（代谢能12.81 MJ/kg,粗蛋白质13.04%）和添加1000 mg/kg甜菜碱的高能量低蛋白质日粮60 d。于试验期第1、30、60天,每组取8只鸡采血制备血清和采集肝脏样品及腹脂,测定血脂含量、肝脂率和腹脂率,结合产蛋性能及病理学变化,综合判定脂肪肝出血综合征(fatty liver hemorrhagic syndrome,FLHS)的发生及甜菜碱的预防效果。结果表明,与对照组相比,饲喂高能量低蛋白质日粮30 d即可引发FLHS,饲喂60 d则病情进一步加重;而在高能量低蛋白质日粮中添加1000 mg/kg甜菜碱后,饲喂30 d时甜菜碱可显著抑制FLHS的发生,具有很好的预防作用,但饲喂60 d时甜菜碱的预防作用减弱。     

强制换羽对蛋鸡生产性能和蛋品质的影响

旨在研究强制换羽对蛋鸡生产性能和蛋品质的影响。选取80周龄海兰褐蛋鸡4 500只,分为A、B、C组,每组1 500只,于试验组Ⅰ区饲养;选取60周龄海兰褐蛋鸡3 000只,分为D、E组,每组1 500只,于试验组Ⅱ区饲养;另选取60周龄海兰褐蛋鸡1 500只（F组）,于对照组Ⅲ区饲养。试验组Ⅰ区和试验组Ⅱ区位于同一栋鸡舍,对照组Ⅲ区位于另外一栋鸡舍。采取饲料、饮水、光照控制的方式对A~E组鸡群进行强制换羽处理;F组不进行强制换羽处理。试验包括7 d的预试期和56 d的正试期。在正试期内,测定各组鸡群的产蛋率、蛋品质指标、死亡率。结果表明：与换羽前相比,强制换羽后A、B、C组的平均产蛋率的提高幅度为27.1%,强制换羽后D、E组的平均产蛋率的提高幅度为16.1%,换羽后F组的平均产蛋率的降低幅度为5.5%;5个接受强制换羽处理的试验组（A~E组）与对照组（F组）相比,蛋重增加2.5%,蛋壳强度提高11.8%,蛋白高度提高8.8%,蛋形指数提高3.3%,蛋壳尖端的厚度提高14.8%;5个接受强制换羽处理的试验组（A~E组）的平均死亡率为2.5%,对照组（F组）的死亡率为1.5%。综上所述,强制换羽技术的应用可以明显提高海兰褐蛋鸡的产蛋率,并提升蛋品质。     

Importance of the rearing period for laying hens in alternative systems

Feather pecking and cannibalism are still major problems in alternative systems for laying hens. Literature and practical experience indicate that unfavourable rearing conditions might be important risk factors for the occurrence of these behavioural disturbances during the laying period.Typical rearing conditions of laying hens from 50 rearing units in Germany and Austria are presented. Obvious risk factors during rearing for feather pecking and cannibalism during the laying period were found. Most flocks were kept under high stocking density (mean: 15 pullets per m' useable area) and some flocks had access to litter only after the second week of life or access to raised perches after the fourth week of life. Plumage condition of pullets and laying hens varied widely in non-beak-trimmed as well as in beak-trimmed flocks.The percentage of pullets with damaged plumage was higher in beak-trimmed than in non-beak-trimmed flocks (medians: 53 % versus 30 %, p = 0,022). In laying hens there was a higher percentage of hens with plumage damage in non-beak-trimmed flocks compared to beak-trimmed flocks (medians: 23 % versus 50 %, p = 0,007). Data analysis will be continued, especially with regard to particular risk factors.     

维生素E对蛋鸡肉品质的影响

本试验旨在研究蛋鸡日粮中添加不同剂量的维生素E对蛋鸡肉品质的影响.试验选取健康无病且生产性能相近的400日龄海兰灰蛋鸡224只,随机分成4组,每组4个重复,每个重复14只,维生素E添加水平分别为0、0.075、0.15、0.3 g/kg,试验期4周.结果表明:维生素E对肉品质有一定影响,添加维生素E对提升宰后24h腿肌pH、降低胸肌腿肌煮熟损失、提高腿肌系水力、降低腿肌剪切力均有显著影响(P＜0.05),日粮中添加维生素E 0.15 g/kg和0.3 g/kg,能显著提高鸡腿肉色L值(P＜0.05).综合评定结果显示,0.15 g/kg的维生素E为适宜添加量.     

海藻饲料添加剂对蛋鸡产蛋性能、血清抗氧化性及生长的影响

试验研究了在蛋鸡饲粮中添加不同剂量的海藻饲料添加剂对蛋鸡产蛋性能、血清抗氧化性、生长及营养物质消化率等的影响。选取360只26周龄体重相近的海兰褐蛋鸡,随机分为6组(每组3个重复,每个重复20只鸡),1组为空白对照组,饲喂基础饲粮;2组为抗生素对照组,在基础饲粮中添加0.005%的杆菌肽锌;3~6组为试验组,分别在基础饲粮中添加0.02%、0.04%、0.06%、0.08%的菊粉,0.025%、0.050%、0.100%、0.150%的大西洋海藻粉及相同剂量的铜藻粉(以下简称低、中、较高、高剂量海藻复合物),预试期7 d,正式试验期63 d。结果表明:海藻饲料添加剂对蛋鸡的产蛋性能有明显的剂量-效应关系,添加量为中等剂量海藻复合物(4组)时最佳且差异显著(P<0.05)。此添加量下,蛋鸡血清中超氧化物歧化酶活性最高(P<0.05)。试验中粗纤维的表观消化率随添加剂量的增加而增加(P<0.05)。低剂量试验组体重增长最多且差异显著(P<0.05)。试验结果表明,基础饲粮中添加中剂量海藻复合物作为蛋鸡饲料添加剂,能够显著提升蛋鸡产蛋性能及血清抗氧化性。     

不同饲养方式对蛋鸡生产性能、鸡蛋品质及经济效益的影响

文章旨在评估不同饲养方式对蛋鸡生产性能、蛋品质和血清生化指标的影响。试验选择产蛋性能接近的22周龄海兰褐壳蛋鸡540只,随机分为3组,每组5个重复,每个重复36只。笼养组蛋鸡采用三层阶梯饲养（0.6 m2/只）,网上平养组蛋鸡在金属网丝上饲养（1.5 m2/只）,垫料平养组在平铺20 cm稻壳的水泥地板上平养（1.8 m2/只）。试验共开展28周,包括2周的适应期。结果：网上平养和垫料平养组24～36 w和24～29 w蛋鸡平均日采食量较笼养组蛋鸡分别显著提高5.71%、6.22%和4.81%、4.48%（P＜0.05）。此外,垫料平养组24～36 w和24～49 w蛋鸡的料重比较笼养组分别显著提高7.31%和4.09%（P＜0.05）。在36 w时,垫料平养组鸡蛋的蛋壳强度最高,脏蛋率最低（P＜0.05）。在49 w时,笼养组鸡蛋的蛋壳厚度最低（P＜0.05）,脏蛋率最高（P＜0.05）。笼养组蛋鸡血清葡萄糖、甘油三酯、总蛋白和胆固醇浓度均最高（P＜0.05）,但高密度脂蛋白浓度最低（P＜0.05）。结论：网上平养和垫料平养可以提高蛋鸡采食量,但笼养蛋鸡的饲料效率表现最佳。此外,垫料平养提高了鸡蛋的蛋壳强度和蛋壳厚度,降低了破蛋率。     

The effect of changing the excreta moisture of caged laying hens on the excreta and microbial contamination of their egg shells

1. An experiment that included 1440 caged laying hens in 24 experimental units was conducted to determine the effect of differences in excreta moisture on the proportion of dirty eggs and the microbial contamination of eggs that were ostensibly uncontaminated by excreta. Excreta moisture contents were changed by giving the hens diets that contained 4 different concentrations of sodium. 2. Diets containing 1.6, 5, 10 or 15 g/kg dietary sodium were fed ad libitum to 1140 laying hens for a 12-week feeding period. A sample of excreta was collected from each experimental unit each week and its moisture content determined. All eggs produced were classified as clean or dirty according to the European Community Egg Marketing Regulations. A sample of eggs were collected from each experimental unit on 4 separate occasions in the last 4 weeks of the feeding period and the total bacterial numbers on ostensibly clean egg shells were determined. 3. Increasing dietary sodium concentration gave linear (P<0.01) increases in excreta moisture. Each 100 g/kg increase in excreta moisture increased (P<0.001) dirty egg numbers by 0.52% of the total eggs produced. Increasing excreta moisture gave a linear increase (P<0.001) in the (log-transformed) numbers of microorganisms that contaminated ostensibly clean egg shells.     

Rare earth element‐enriched yeast improved egg production and egg quality in laying hens in the late period of peak egg production

The objective of this study was to determine the effects of rare earth element‐enriched yeast (RY) on egg production, coefficient of total tract apparent digestibility (CTTAD), egg quality, excreta gas emission and excreta microbiota of laying hens. A total of 216 ISA brown laying hens of 52 weeks of age were used in a 5‐week feeding trial and data were collected every week. Birds were randomly allotted to three dietary treatments each with six replicates and 12 hens per replicate. Each cage (38 cm width × 50 cm length × 40 cm height) contained one hen. Treatments consisted of corn–soya bean meal‐based diet supplemented with 0, 500 or 1000 mg/kg of RY. From weeks 55 to 56, inclusion of RY linearly increased (p < 0.05) egg production. The CTTAD of nitrogen was increased (linear, p < 0.05) with increasing dietary level of RY. In week 55, yolk height and Haugh units were increased linearly (p < 0.05) with increasing dietary RY content. However, no significant effects were observed in terms of excreta emissions and excreta microbiota in laying hens. In conclusion, dietary supplementation with RY improved egg production and CTTAD of nitrogen and slightly improved egg quality in laying hens of the late period of peak egg production.