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.     

Strain Response of Laying Hens to Varying Dietary Energy Levels With and Without Avizyme Supplementation

The response of 4 strains of laying hens fed diets varying in ME with and without Avizyme 1500 (AVI) supplementation was evaluated in a factorial arrangement study. The strains of laying hens (Hy-Line W-36, Hy-Line Brown, Babcock B300, and Shaver White) were fed 3 diets: moderate ME (2,900 kcal/kg), low ME (2,810 kcal/kg), and low ME with AVI for 28 wk commencing at 22 wk of age. No significant effects of diet, strain, or their interaction on feed intake and BW change were observed. Lack of an effect on feed intake was surprising given the different levels of ME. It is hypothesized that the reduced dietary ME was not low enough to elicit a response. Of course, dietary level of ME did change caloric intake among hens, with hens fed moderate ME consuming more calories than those fed low ME with or without AVI. There was an interesting dietary ME × strain interaction effect on egg production (EP). Babcock B300 hens fed moderate ME and low ME with AVI had greater EP compared with the B300 hens fed low ME, whereas the Shaver White hens had a greater EP when fed a low-ME diet compared with feeding a moderate-ME diet or low-ME diet with AVI. Egg weight and egg mass were significantly affected by strain but not by diet ME. Hy-Line Brown and Babcock B300 hens laid eggs with greater weight and mass in contrast to Hy-Line W-36 or Shaver White. Hy-Line Brown eggs were the largest, whereas Shaver White had greatest egg-specific gravity. Strain significantly affected proportions of albumen vs. yolk in the egg. Across all strains, Hy-Line Brown had more albumen percentage, whereas Hy-Line W-36 had higher wet yolk and yolk solids percentages. The low-ME level fed to laying hens may have been too high to evoke an enzyme response to improve energy utilization by birds. This is important, because to obtain an economic benefit, producers would need to know the proper ME level to feed with the supplemental enzymes.     

Effects of stocking density and group size on the performance of white and brown Hyline layers in semi-arid conditions

The effect of housing two Hyline strains of commercial laying hens White Hyline (W-98) and Brown Hyline (Hyline Brown) at densities of 2, 3 or 4 per cage (1100, 733 or 550 cm²/hen, respectively) was investigated over 3 months. Hyline Brown layers gained more weight, laid more but lighter eggs, utilized feed more efficiently and had a lower mortality than W-98 layers. Housing birds 2 or 3 per cage resulted in greater body weight gain, higher egg production, heavier eggs, better feed conversion ratio and a lower mortality than housing them 4 per cage. There were significant interactions between strain and stocking density for egg production, egg weight, egg output and mortality. It is suggested that for egg production in semi-arid areas Hyline Brown hens could be used and housed at a density of 733 cm²/hen.     

Differential Effects of Heat Stress in Three Strains of Laying Hens

Hy-Line Brown, W36, and W98 hens were housed for 2 wk at 22°C, exposed to 35°C heat stress (HS) for 2 wk, and had 2 wk of recovery at 22°C. Production parameters (egg production, feed intake, egg quality measures, and mortality), acid-base status (pH, pCO₂, HCO₃⁻, pO₂), intestinal calcium uptake, and expression of hepatic heat shock protein-70 were measured. All production parameters except mortality were reduced by HS in all 3 strains. There were strain × temperature interactions for egg production, feed intake, shell thickness, specific gravity, and yolk weight, with the least severe reduction in W98 hens. The W36 hens were intermediate for egg production and feed intake, and the Brown and W36 hens were equivalent for shell thickness, specific gravity, and yolk weight. There were no interactions for egg, albumen, and shell weights, Haugh units, and intestinal calcium uptake, and all were reduced by HS. Blood pH and pCO₂ were reduced by HS, and hepatic heat shock protein-70 was increased, with no differences among strains. Mortality rates during HS were 16, 8, and 4% for the Brown, W98, and W36 hens, respectively, but were not subjected to statistical analysis. The results suggest a mechanism in the W98 bird that appears to confer an advantage during HS with regard to egg production.     

Effect of dietary energy,protein, and a versatile enzyme on hen performance,egg solids,egg composition,and egg quality of Hy-Line W-36 hens during second cycle,phase two

This study was conducted to evaluate the effect of Rovabio, dietary energy, and protein on performance, egg composition, egg solids, and egg quality of commercial Leghorns in phase 2, second cycle. A 4 × 2 × 2 factorial arrangement of treatments comprising 4 dietary energy levels (2,791, 2,857, 2,923, and 2,989 kcal of ME/kg) and 2 protein levels (15.5 and 16.1%) with and without Rovabio was used. Hy-Line W-36 hens (n = 1,920, 87 wk old) were randomly divided into 16 dietary treatments (8 replicates of 15 hens per treatment). The trial lasted 12 wk. Dietary protein significantly increased feed consumption but decreased yolk color. As dietary energy increased from 2,791 to 2,989 kcal of ME/kg, feed consumption decreased from 98.0 to 94.9 g per hen daily, and yolk color increased from 5.27 to 5.56. There was a significant interaction among dietary protein, energy, and Rovabio on egg production, BW, egg mass, feed conversion, and yolk solids. Egg weight of hens fed the diets supplemented with Rovabio was significantly greater than that of hens fed the diets without Rovabio during wk 3 and 4. However, Rovabio did not significantly influence average egg weight (87 to 98 wk of age). Rovabio supplementation significantly increased BW of hens. These results suggest Rovabio had a small but significant influence on nutrient utilization of commercial Leghorns during phase 2 of the second cycle.     

The influence of different beak trimming age on performance, H-L ratio and antibody production to SRBC in laying hens

The objectives of this study were to examine the effects of beak trimming age on performance criteria, H-L ratio, antibody production, the percentage of spleen and liver and external appearance. The chicks (Barred Rock) were randomly divided into 4 beak-trimming groups (non-trimmed (control), a trim at 1 d (1D), at 10 d (10D) and at 10 wk (10W)), each of 132 chicks. There were 6 replicate cages at beak trimming groups at rearing period. At 18 wk of age a total of 144 pullets were transferred to the layer house, and the pullets were housed at 323 and 646 cm²/hen with 8 and 4 birds per cage in three-deck layer cages. There were a total of 24 replications with 12 replications equally divided between the high and low density cages, and the beak trimmed treatments were randomly and equally divided within each density. As a result of this experiment differences among groups in body weight in rearing phase were disappear in the laying phase. Low feather condition was found in untrimmed hens. H-L ratio in both pullet and laying phase was higher in hens of untrimmed groups. Cage area affected all examined parameters except that body weight, mortality rate, cracked, broken and unshell egg rates, shell breaking, shape index, shell thickness, meat-blood spot rates, spleen and liver percentages, throat injures and antibody production to SRBC.     

Egg production, egg weight, eggshell strength, and mortality in three strains of commercial layers vaccinated with F strain Mycoplasma gallisepticum

Three strains of commercial leghorns vaccinated at 17 to 22 weeks of age with F strain Mycoplasma gallisepticum (MG) were maintained through 117 weeks of age. The three strains differed in both mortality and percent egg production per hen housed; however, the strains did not differ in egg weight (EW), eggshell strength (ESS), or percent daily egg production. Results of this study indicate EW and ESS for F strain MG-vaccinated hens follow patterns previously reported for uninfected layers. Further, mortality may account, in part, for differences in percent egg production per hen housed between strains of F strain MG-vaccinated hens.     

益生菌-中草药复方制剂对海兰褐蛋鸡输卵管组织、生产性能及蛋品质的影响

试验旨在研究益生菌-中草药复方制剂对蛋鸡输卵管组织、生产性能及蛋品质的影响。选取体质优良的45周龄的海兰褐蛋鸡720只,随机分成4组,每组3个重复,每个重复60只。对照组饲喂不含抗生素的基础日粮,Ⅰ、Ⅱ和Ⅲ组为试验组,分别在基础日粮中添加1.0‰中草药组方一(败酱草、蒲公英、板蓝根、连翘等)、1.0‰中草药组方二(金银花、黄芪、淫羊藿、益母草等)和1.0‰中草药组方三(大青叶、黄柏、黄芩、栀子等),且各试验组均添加1.5‰复合益生菌。预试期7 d,正试期28 d。结果表明:①益生菌-中草药复方制剂能修复蛋鸡受损的输卵管组织,减少输卵管与周围组织的黏连,使输卵管保持通畅性,降低蛋鸡输卵管组织中肿瘤坏死因子-α(TNF-α)和表皮生长因子受体(EGFR)含量,尤以Ⅱ组效果最好,分别较对照组降低40.85%和17.79%,差异显著(P<0.05);②与对照组相比,Ⅱ组可显著提高蛋鸡产蛋率(P<0.05),显著降低料蛋比和软破蛋率(P<0.05);③与对照组相比,Ⅱ组可显著提高48和50周龄蛋鸡的蛋形指数和蛋黄比率(P<0.05)。由此可知,日粮中添加益生菌-中草药复方制剂能在一定程度上减轻蛋鸡输卵管炎症反应,提高产蛋率,改善蛋品质,其中以Ⅱ组益生菌和金银花、黄芪、淫羊藿、益母草等中草药联合使用效果最好。     

Perch Arrangements in Small-Group Furnished Cages for Laying Hens

In 2 trials, including 2,768 birds in total, 3 different perch arrangements were evaluated in furnished 8-hen cages for laying hens. The hybrids used were Lohmann Selected Leghorn and Lohmann Brown in trial 1 and Hy-Line White and Hy-Line Brown in trial 2. The furnished cages were identical in all other respects than the arrangement of perches. A perch was either fitted across the cage, providing 12 cm of perch per hen, or 2 perches were installed in a cross, implying 15 cm per hen. Although the perches arranged in a cross provided more perch per hen than the single perch fitted across the cage, perch use at night by the birds was similar or lower as compared with the single perch. Hence, the way perches are arranged in the cage may be as important as perch length itself to achieve a high use at night. Perch arrangement did not affect production, mortality, or egg quality. Compared with a conventional battery cage, also included in the trials, hygiene was inferior in the furnished cages, but there was no difference in proportions of dirty eggs. Differences in proportions of cracked eggs were found between furnished and conventional cages in 1 of the trials. However, on the whole, production, mortality, and egg quality were at similar levels in all cage models. Genotype differences were found in production traits, egg quality, hygiene, and in the use of perches and nests.     

发酵饲料对海兰褐蛋鸡生产性能及蛋品质的影响

旨在研究发酵饲料对海兰褐蛋鸡生产性能及蛋品质的影响。以玉米和豆粕为发酵底物,利用乳酸菌和酿酒酵母菌进行发酵。选取336日龄的海兰褐蛋鸡600只,随机分为4组,每组150只,3个重复,每个重复50只。试验Ⅰ、Ⅱ、Ⅲ组的基础日粮中分别添加3%、5%、8%的发酵饲料,对照组基础日粮中不添加发酵饲料。饲喂试验周期为4周,期间测定各组蛋鸡的生产性能及蛋品质相关指标。结果表明,基础日粮中添加不同比例的发酵饲料,均可在一定程度上改善蛋鸡的生产性能和蛋品质,其中：饲喂发酵饲料第2周,试验Ⅱ组的产蛋数与对照组相比显著（P<0.05）增加;饲喂发酵饲料第3周,试验Ⅱ组的产蛋数和总蛋重与对照组相比均显著（P<0.05）提高;饲喂发酵饲料4周后,试验Ⅱ组的产蛋数、总蛋重、产蛋率与对照组相比均显著（P<0.05）提高,并且料蛋比显著（P<0.05）下降;试验Ⅱ组的蛋壳强度显著（P<0.05）高于对照组;试验Ⅱ组和Ⅲ组的哈氏单位显著（P<0.05）高于对照组。综上提示,在基础日粮中添加不同比例的发酵饲料,可在一定程度上提高海兰褐蛋鸡的生产性能及蛋品质,其中,5%添加水平的效果最佳。     

海兰褐蛋鸡和京粉2号蛋鸡的生长发育规律及初产蛋品质比较研究

[目的]研究相同饲养条件下海兰褐蛋鸡苗和京粉2号蛋鸡苗的生长发育规律,评价其初产蛋品质.[方法]选取1日龄海兰褐蛋鸡苗和京粉2号蛋鸡苗各500只,在相同条件下饲养,每周随机挑选60只个体测量体重,直到13周龄试验结束.采用Logistic、Gompertz和Von Bertalanffy 3种曲线模型对2种鸡苗的生长发...     

Comparative Pigmentation Efficiency of High Dietary Levels of Apo-Ester and Marigold Extract on Quality Traits of Whole Liquid Egg of Two Strains of Laying Hens

This trial was carried out to compare the effect of the dietary supplementation of high doses of either synthetic pigment ethyl ester of β-apo-8′-carotenoic acid (apo-ester) or natural pigments, mainly lutein and zeaxanthin, extracted from Tagetes erecta, on egg quality of hens laying brown shell eggs (ISA Brown) and white shell eggs (Hy-Line White W-36). The hens of each strain were divided into 6 groups and fed a corn-soybean basal diet supplemented either with 40, 60, and 80 ppm of apo-ester (APO) or with 120, 180, and 240 ppm of marigold extract (MAR). Egg pigmentation rose linearly and significantly (P < 0.01) as the dietary levels of apo-ester increased, but this did not occur when MAR supplementation was used. The amount of β-carotene equivalents in whole liquid egg of MAR treatments was almost constant with varying pigment dietary dose and was significantly lower (P < 0.01) than in APO treatments. In both hen strains, whole liquid egg redness (a*) and yellowness (b*) were higher with APO supplementation. The egg component weights were highly affected (P < 0.01) by the hen strain, with yolk:egg ratio higher in the Hy-Line. The trial confirms that in spite of the higher level of MAR supplementation, APO has a better efficiency in whole liquid egg pigmentation. The ISA Brown hens showed a better ability to absorb dietary carotenoids than did the Hy-Line White.     

枯草芽孢杆菌CGMCC 1.921对蛋鸡生产性能、血常规指标、血清生化指标及免疫球蛋白含量的影响

本试验旨在研究枯草芽孢杆菌CGMCC 1.921对蛋鸡生产性能、血常规指标、血清生化指标及免疫球蛋白含量的影响。选用27周龄健康的海兰褐壳蛋鸡360只,随机分为5个组,每个组6个重复,每个重复12只鸡。对照组(1组)饲喂基础饲粮,试验组(2~5组)分别在基础饲粮中添加1.0×105、1.0×106、1.0×107和1.0×108CFU/g枯草芽孢杆菌CGMCC 1.921。试验期24周。结果表明:各组产蛋率、采食量、蛋重、只产蛋量及死淘率均无显著差异(P0.05),但试验2、4、5组料蛋比显著低于对照组(P0.05);饲粮添加枯草芽孢杆菌CGMCC 1.921显著升高了血清葡萄糖含量(第2、3、12、16、20周)(P0.05),显著降低了血清尿素含量(第2、3、8、12周)(P0.05);饲粮添加枯草芽孢杆菌CGMCC 1.921显著提高了血液白细胞(第1、3、4、8、12、16、20、24周)和淋巴细胞数目(第2、3、4、8、12、16、20、24周)(P0.05),显著升高了血清免疫球蛋白G(第1、4周)和免疫球蛋白M含量(第2、4、8、16周)(P0.05)。综上所述,饲粮中添加枯草芽孢杆菌CGMCC 1.921降低了料蛋比,对血清葡萄糖、尿素含量和血常规指标指标有一定改善作用,且在一定程度上促进了蛋鸡免疫力的提升。     

Effect of Energy and Protein on Performance,Egg Components,Egg Solids,Egg Quality,and Profits in Molted Hy-Line W-36 Hens

An experiment was conducted to determine the influence of dietary energy on performance, egg composition, egg solids, egg quality, and profits of Hy-Line W-36 hens fed different protein levels. The experiment was designed as a 4 × 3 factorial arrangement with 4 added dietary energy levels (0, 79, 158, and 238 kcal of ME/kg) and 3 protein levels (14.89, 16.06, and 17.38%). The basal diets of 17.38, 16.06, and 14.89% protein contained 2,751, 2,784, and 2,815 kcal of ME/kg, respectively. This study lasted 12 wk. Molted Hy-Line W-36 hens (n = 1,440) in phase 1 (70 wk of age) were randomly divided into 12 treatments (8 replicates of 15 hens per treatment). Protein had a significant effect on egg production, egg mass, feed intake, feed conversion, egg weight, percentage of egg shell components, yolk color, and yolk and albumen weight. As dietary energy increased from 0 to 238 kcal of ME/kg by addition of poultry oil, feed intake linearly decreased. Increasing dietary energy also significantly increased BW and egg yolk color. As dietary energy increased, percentage yolk solids increased at the 2 greater dietary protein levels, whereas egg-specific gravity linearly decreased at the 17.38% protein level. Increasing dietary energy and protein significantly improved feed conversion. Increasing protein intake significantly increased albumen and yolk weight but had no influence on yolk, albumen, or whole egg solids. Because feed ingredient and egg prices vary, there can be no fixed ideal dietary energy level for optimal profits during molt phase 1 (70 to 81 wk).     

Feed formulation using phytase in laying hen diets

Lohmann LSL-Lite and Classic Brown laying pullets were reared and caged at the Agassiz Research Centre following recommendations of the management guides. At 30 wk of age, these hens were fed 1 of 5 diets per strain following the Lohmann nutrient recommendations. In addition to a control treatment, diets were formulated to contain 300 or 600 U/kg of phytase, with or without enzyme inclusion, where the phytase was assumed to cause the release of P, Ca, energy, and protein. Diets were changed at 45 wk to follow a phase-feeding program, but treatments remained the same. These dietary changes did not result in major changes in measures associated with P deficiency, likely because the management guides suggest P levels that largely exceed the requirements of the birds. Rather than adding high levels of inorganic P to layer feeds, the safety margin currently included in recommended dietary specifications could be provided by the addition of phytase. This would reduce the negative environmental effects of intensive poultry production that are associated with P excretion.     

30～38周龄产蛋鸡理想氨基酸模式的研究

本试验旨在通过4个剂量-反应试验,研究30～38周龄产蛋鸡对赖氨酸(Lys)、蛋氨酸(Met)、色氨酸(Trp)和苏氨酸(Thr)4种必需氨基酸(AA)的需要量及其比例.每个试验均采用360只海兰灰产蛋鸡,设5个处理,分别采食5个AA梯度水平的试验饲粮,每个处理6个重复,每个重复12只鸡.采用蛋公鸡回肠食糜法测定饲料原料的标准回肠可消化(SID)值.试验预试期14 d,正试期56 d.结果表明:海兰灰产蛋鸡的产蛋率、蛋重、日产蛋量和料蛋比与SIDLys、SID Met、SID Trp和SID Thr的摄入水平均有较好的折线回归关系;以日产蛋量为自变量(x),AA摄入水平为依变量(Y)分别建立的回归方程为:YSID Lys=51.60-0.041 6(682.5-x),R2=0.96;YsID Met=51.43-0.085(314.1-x),R2 =0.95;YSID Trp =51.17-0.155 4(163.0-x),R2=0.97;YsID Thr=52.85-0.057 6(499.5-x),R2=0.93.在饲粮粗蛋白质12.8％的条件下,以日产蛋量为参照指标确定的30 ～ 38周龄产蛋鸡的SID Lys、SID Met、SID Trp和SID Thr需要量分别为684、313、171和506 mg/(只·d).以日产蛋量为指标建立的30～38周龄产蛋鸡理想SID AA模式为:Lys:Met:Trp:Thr=100∶46∶24∶73.     

饲粮添加酵母寡聚糖对高密度养殖条件下蛋鸡生产性能、蛋品质、血清生化指标和肠道健康的影响

本试验旨在研究饲粮中添加酵母寡聚糖(YOS)对高密度养殖条件下蛋鸡生产性能、蛋品质、肠道黏膜形态结构及微生物区系分布、血清生化指标和肠道功能相关基因表达的影响。选取864只12周龄海兰褐蛋鸡,随机分为6个组,每组12个重复,每重复3个笼子,每个笼子3只(低密度)或5只(高密度)。对照组饲喂基础饲粮,试验组饲喂在基础饲粮中分别添加250和500 g/t YOS的饲粮,试验期18周。结果表明:1)饲粮添加YOS能显著提高蛋壳颜色的均匀度(P0.05)。2)饲粮添加YOS增加了蛋鸡肠道绒毛高度/隐窝深度值(P=0.059),其中250 g/t YOS组显著高于对照组(P0.05)。3)饲粮添加YOS使得蛋鸡空肠乳酸杆菌数量显著增加(P0.05),大肠杆菌数量显著减少(P0.05),其中250 g/t YOS组菌群变化较为明显。4)饲粮添加YOS显著降低了蛋鸡血清中内毒素含量(P0.05),提高了免疫球蛋白A含量(P=0.090),且250 g/t YOS组较对照组显著提高(P0.05)。由此可见,饲粮中添加YOS能够改善高密度养殖条件下蛋鸡肠道功能,添加剂量以250 g/t的综合效果较佳。     

粪肠球菌对产蛋后期蛋鸡生产性能、蛋品质及肠道组织形态的影响

试验旨在研究添加不同剂量的粪肠球菌对产蛋后期蛋鸡生产性能、蛋品质及肠道形态结构的影响。选取70周龄产蛋率相近的海兰褐蛋鸡270只,随机分为3个处理,每个处理6个重复,每个重复15只鸡。试验设对照组（饲喂基础日粮）、试验Ⅰ组（基础日粮+3.75 mg/kg粪肠球菌）和试验Ⅱ组（基础日粮+7.5 mg/kg粪肠球菌）,预试期7 d,正试期50 d。结果表明,与对照组相比,试验Ⅰ、Ⅱ组产蛋后期蛋鸡产蛋率、产蛋量极显著提高（P<0.01）,料蛋比极显著降低（P<0.01）;与对照组相比,试验Ⅰ、Ⅱ组蛋鸡的蛋壳厚度、蛋壳强度、蛋形指数、蛋白高度、哈夫单位、蛋黄相对重、蛋壳相对重均无显著变化（P>0.05）;与对照组相比,试验Ⅰ、Ⅱ组产蛋后期蛋鸡十二指肠、回肠的黏膜厚度极显著增加（P<0.01）,回肠绒毛高度显著提高（P<0.05）。综上所述,在产蛋后期蛋鸡日粮中添加适宜剂量的粪肠球菌可提高蛋鸡生产性能,改善肠道形态结构。     

Feed particle selection and nutrient intake altered by pecking stone consumption and beak length in free-range laying hens

The present study investigated the effects of pecking stones on feeding behaviour of hens from 16 to 46 weeks of age. Eighteen flocks of Hy-Line Brown hens were housed in 2 commercial free-range housing systems. Farm A housed 10 flocks of beak trimmed (infrared beak treatment) hens in fixed sheds. Farm B housed 8 flocks of hens with intact beaks in mobile sheds. On each farm, flocks were equally assigned to control groups (no access to pecking stones) and treatment groups (access to pecking stones). Data were evaluated every 10 weeks. At each time point, 10 hens per flock were housed in individual pens, and each hen was provided with 250 g of mash diet and ad libitum water for 24 h. After 24 h, feed samples were collected and used to determine 24-h feed intake. Nutrient and particle selection was measured by subtracting nutrients and particles present in the leftover feed from the vaules obtained in the offered feed and expressed the change (Δ). In addition, pecking stone consumption was recorded for each flock. Data were analysed separately for each farm using fixed effects of pecking stone availability and hen age. Spearman's rho correlation coefficients and linear regression models were constructed to evaluate the relationship of beak length and pecking stone usage, discrete mean particle size (dMEAN) consumption (Δ dMEAN), and Δ nutrient intake. Hens with access to pecking stones consumed significantly lower quantities of large feed particles (>2.8 mm) on farm A (P = 0.029) and selected significantly more fine particles, on farm B (P = 0.013). Overall, positive relationships (P = 0.001) between beak length and pecking stone consumption, Δ dMEAN, and Δ phosphorus consumption were observed. In conclusion, pecking stone consumption resulted in reduced selection and consumption of feed particles in hens housed on both farms. Further research is warranted to investigate the effect of pecking stones on sensory innervation of the beak.     

Evaluation of feeding spray-dried bovine plasma protein on production performance of laying hens exposed to high ambient temperatures

The purpose of this study was to evaluate feeding 2 levels of spray-dried bovine plasma protein (SDP) on production performance of laying hens subjected to high ambient temperatures. Two groups of 96 Hy-Line W-98 hens (38 wk of age) were housed in each of 2 environmentally controlled chambers. At 40 wk of age, all hens were fed 3 diet treatments consisting of (1) a control diet (0% SDP); (2) the control diet supplemented with 0.75% SDP; and (3) the control diet supplemented with 1.50% SDP. Hens in each chamber (8 cages of 4 hens per cage) were ad libitum fed 1 of each diet for 5 wk. The heat stress (HS) chamber was maintained at 21°C (wk 1), 29°C (wk 2), and 35°C (wk 3 to 5). The thermoneutral chamber was maintained at 21°C during wk 1 to 5. A significant main effect of week was observed for hens maintained in the HS chamber for egg production, egg weight, egg mass, and feed consumption, which resulted in acute heat stress causing a reduction in these parameters. Hens fed the 1.50% SDP diet in the HS chamber produced greater (P < 0.05) egg mass on average than hens fed the control or 0.75% SDP diet (wk 1 to 5). During the second week of acute HS (wk 4), hens fed the control and 1.50% SDP diets had greater (P < 0.05) egg production than those fed the 0.75% SDP diet. During wk 5, hens in the HS chamber that were fed the 1.50% SDP diet produced more (P < 0.05) eggs than those fed the control diet. Therefore, based on the results of this study, acute HS negatively affected short-term production performance. In addition, feeding hens an SDP-supplemented diet may have a slight positive effect on production performance when maintained in acute HS conditions.