外源促性腺激素处理后鸡产蛋及孵化研究

目的:探讨促卵泡素(FSH)对低产期肉用种母鸡在产蛋数量和孵化的影响,寻求较佳的用于提高低产期母鸡产蛋的激素剂量。方法:本试验采用同种激素不同剂量的处理方式,比较实验组和对照组产蛋量和孵化情况。结果:注射不同剂量的激素对鸡的产蛋有一定的影响,实验组一的平均产蛋数与对照组接近,其它四组均显著低于对照组(P<0.05),孵化率与健雏率与对照组无显著差异(P>0.05)。结论:小剂量激素处理对鸡产蛋量没有太大的影响,但大剂量会引起鸡生殖系统萎缩,激素处理对受精卵孵化及雏鸡生长并无负面影响。     

外源促性腺激素处理后鸡产蛋及孵化研究

目的：探讨促卵泡素（FSH）对低产期肉用种母鸡在产蛋数量和孵化的影响,寻求较佳的用于提高低产期母鸡产蛋的激素剂量。方法：本试验采用同种激素不同剂量的处理方式,比较实验组和对照组产蛋量和孵化情况。结果：注射不同剂量的激素对鸡的产蛋有一定的影响,实验组一的平均产蛋数与对照组接近,其它四组均显著低于对照组（P〈0．05）,孵化率与健雏率与对照组无显著差异（P〉0．05）。结论：小荆量激素处理对鸡产蛋量没有太大的影响,但大剂量会引起鸡生殖系统萎缩,激素处理对受精卵孵化及雏鸡生长并无负面影响。     

鸡持续高尿酸血症模型的制备方法研究

目的 探讨制备鸡持续高尿酸血症动物模型的方法,以及成模动物高尿酸血症与痛风性关节炎的关系.方法 随机将28日龄岭南黄健康雄性鸡分为4组,造模组3组分别用高嘌呤饲料(A)、普通饲料(B)、高蛋白质高钙饲料(C)饲喂并限水;另设1组为空白对照组(D),普通饲料饲喂不限水.成模后继续饲喂至出现关节肿胀畸形等改变.结果 血尿酸值增加速度和幅度依次为C组>A组>B组>D组,C组和A组达到高尿酸(>476.57 μmol·L-1)的时间分别为1周和3周,与空白对照组比较差异显著(P<0.05).C组1只160日龄鸡出现右膝关节肿胀,处死后病检观察证实为痛风性关节炎改变.结论 鸡持续高尿酸血症模型可用70日龄以下雏鸡成功制备;高蛋白质高钙饲料和限水是造模成功的重要因素;高蛋白质高钙饲料致雏鸡高尿酸血症时伴有体重的快速增长;高尿酸血症持续3周后鸡跗踝周径明显增大;痛风性关节炎的发生与高尿酸血症持续的时间有关.     

促排卵周期中未破裂黄素化卵泡综合征与性激素的关系探讨

目的:对未破裂黄素化卵泡综合征(LUFS)周期及正常排卵周期患者在不同时间性激素进行测定与比较,探讨LUFS的发生与性激素的关系。方法:对自然周期有排卵障碍的患者使用克罗米芬+HCG促排,分别在月经周期的第3天(C3)、第10天(C10)、卵泡成熟日(CM)(卵泡直径≥18mm)、尿LH阳性或注射HCG后48小时(CL)进行性激素测定,根据患者是否有排卵分为:正常排卵组(A组);未排卵出现LUFS组(B组)。选择同期自然周期正常排卵者为对照组(C组),同上法进行性激素测定。对A、B、C组患者不同时间的血清性激素进行比较。结果:1、FSH:在CM日A、B两组的促卵泡成熟激素(FSH)均低于C组(P<0.01)。2、LH:在C3、C10、CL日测定的A、B组LH值均高于C组(P<0.01),在CM日测定的A、B组LH值低于C组(P<0.01)。3、P:在CM日A、B两组的孕酮值低于C组(P<0.01);4、E2:在C3日测定的B组E2值低于C组(P<0.01),在CL日测定的B组E2值高于C组(P<0.01);5、PRL:在不同时间各组的PRL值均无显著性差异(P>0.05)。6、T:在不同时间各组的T值均无显著性差异(P>0.05)。结论:性激素在LUFS的发生中起重要作用,但以C3日E2值与LUFS的发生的关系最大,E2值低者易发生LUFS。     

菠菜和芫荽对雄性大鼠性功能的影响与植物雌激素样作用研究

目的:研究菠菜、芫荽对雄性大鼠性功能的影响,探讨植物雌激素样作用机制。方法:60只正常雄性SD大鼠,随机分为正常组(N组)、大豆对照组(A组)、菠菜组(B组)、芫荽组(C组)和菠菜+芫荽组(D组),每组12只,不同饲料干预20周后,进行性行为学试验并取材。采用放免法检测各组外周血清中T、E2、LH、FSH和PRL等性腺轴激素含量,HE染色观察睾丸组织形态学变化,IHC和western blot法检测大鼠睾丸中ERα,ERβ蛋白表达。结果:(1)性行为学检测结果:C和D组插入、射精潜伏期较N组显著延长(P0.05),爬背、插入,射精次数较N组显著减少(P0.05);D组插入潜伏期较A组显著延长(P0.05)(2)性激素水平检测结果:D组T水平较N组显著降低(P0.05);C组E_2水平较A组显著升高(P0.05),D组E_2水平较N、A组显著升高(P0.05);C和D组LH水平较N组显著降低(P0.05),同时C组LH水平亦较A组显著降低(P0.05);FSH水平在各组之间无显著差异(P0.05);D组PRL水平较N组显著降低(P0.05)。(3)睾丸HE染色结果:光镜下N组睾丸组织结构完整,B、C和D组睾丸组织形态结构发生明显变化,生精小管间连接疏松,间质细胞减少,生精细胞减少。(4)ERα和ERβ的表达结果:ERα和ERβ分别在睾丸中精原细胞和间质细胞中表达,其中ERα在B、C和D组表达较N组显著增多(P0.05),ERβ在各组间无显著差异(P0.05)。结论:芫荽及菠菜和芫荽联合干预可延长大鼠爬背、插入、射精潜伏期和减少其爬背、插入和射精次数,导致大鼠性功能障碍;具体机制可能与发挥雌激素样作用,升高血清中E_2水平,使ERα在睾丸间质中的表达增多,进而降低T水平有关。芫荽与大豆相比具有更强的雌激素样作用,而菠菜与大豆雌激素样作用接近,菠菜和芫荽联合干预出现累加效应。     

丙氨酰谷氨酰胺对体外循环瓣膜置换术患者的肺保护作用

目的:探讨丙氨酰谷氨酰胺对体外循环瓣膜置换术患者肺屏障功能的影响。方法:择期体外循环(cardiopulmonary bypass,CPB)下行心脏瓣膜置换术患者60例,随机分为3组,每组20例,分别为生理盐水组(C组)、复方氨基酸注射液组(A组)和Ala-GLn组(G组)。G组泵注丙氨酰谷氨酰胺0.4 g/(kg·d),A组和C组分别泵注等量的复方氨基酸注射液和生理盐水,三组均持续输注24 h。分别于:麻醉后(T_0)、开胸后CPB前(T_1)、主动脉开放30 min(T_2)、关胸(T_3)、术后5 h(T_4)、术后24 h(T_5)、术后48 h(T6),经静脉采血3 m L,检测血浆IL-6、TNF-α和SP-A的含量;采动脉血进行血气分析;观察ICU机械通气时间。结果:与T_0比较,三组患者在T_2、T_3、T_4、T_5时间点的血清TNF-α和IL-6含量均显著升高(P0.05);G组患者血清TNF-α和IL-6的浓度显著低于C组和A组(P0.05);与T_0比较,三组患者在T_2~T_5各时间点的SP-A水平显著升高(P0.05),G组患者血清SP-A含量显著低于C组和A组(P0.05);与T_0比较,三组患者在T_2~T_5时的RI值显著升高(P0.05),G组患者RI值显著低于C组和A组(P0.05);G组的机械通气时间比C组和A组显著缩短(P0.05)。结论:丙氨酰谷氨酰胺能降低体外循环瓣膜置换术患者的炎症反应,保护肺泡屏障功能,具有一定的肺保护作用。     

三种不同手术方案对子宫内膜异位囊肿伴不孕症患者卵巢功能的影响

目的:观察和比较开腹剥除术、腹腔镜剥除术及超声引导穿刺术对子宫内膜异位囊肿伴不孕症患者卵巢功能的影响。方法:选取2011年1月-2013年6月我院收治的子宫内膜异位囊肿伴不孕症患者168例,根据患者手术治疗方案分为A、B、C三组,A组患者应用开腹剥除术,B组患者行腹腔镜剥除术,C组给予超声引导穿刺术治疗,对比三组患者手术前后促卵泡成熟激素(FSH)、黄体生成激素(LH)、雌二醇(E2)及窦卵泡数目(AFC)等卵巢储备功能指标水平的变化、临床妊娠数、流产情况及术后复发率。结果:治疗后,三组患者AFC数量均较治疗前显著下降(P0.05),且C组AFC显著高于B、A两组(P0.05);三组患者治疗后血清FSH、E2、FSH/LH水平均较治疗前显著提高,A组血清FSH、E2、FSH/LH水平明显高于B、C组,而C组血清FSH、E2、FSH/LH水平明显高于B组(P0.05)。术后1、2、3年,A组妊娠率均显著低于B、C组(P0.05),且自然流产率显著高于B、C两组(P0.05),而B、C组妊娠率和自然流产率相比差异均无统计学意义(P0.05)。结论:应用超声引导穿刺术及腹腔镜剥除术治疗子宫内膜异位囊肿伴不孕症患者对其卵巢储备功能影响均较小,且妊娠情况较好,临床可根据患者情况选择恰当手术方式,以提高治疗效果。     

鸡Leptin基因正确性的免疫验证

①取20只240日龄的粤黄鸡种母鸡平分为处理组和对照组,分别在第3、31、63和84d对之接种鸡Leptin重组融合蛋白(处理组)或BSA(对照组)1mL/羽。每天记录产蛋率,每10天测定采食量,每两周称重,在试验的第1、31、53、78和91d采血。结果表明Leptin处理组的血浆抗Leptin抗体水平和Leptin水平在免疫后显著高于对照组(P<0.01);第3和4次免疫后处理组产蛋率比对照组显著低约50%(P<0.05);在第98d试验结束时,处理组腹脂量为(115.60±15.07)g,显著高于对照组[(77.98±5.70)g,P<0.05];试验期间处理组的采食量略低于对照组,增重则略高于对照组,但两者差异均不显著(P>0.05);处理组血浆总T3和总T4水平与对照组差异不显著(P>0.05)。②取12只50日龄的粤黄鸡后备小母鸡,平分成处理组和对照组,分别肌注含抗Leptin抗体的卵黄提取液和生理盐水6mL/只,处理组在2、4、6h的累积采食量显著高于对照组(P<0.05),但在8h的累积采食量与对照组差异不显著(P>0.05)。两个试验通过免疫重组鸡Lep tin融合蛋白,使鸡表现出Leptin功能的丧失,证明目前所克隆的鸡Leptin基因在家鸡中的确存在和其正确性。     

不同浓度的右美托咪定对脊柱手术老年患者免疫功能和术后认知功能的影响

探讨不同浓度的右美托咪定在老年脊柱手术患者中应用对免疫功能和认知功能水平的影响。2015 年1 月至 2017 年 1 月,选取我院手术治疗的 90 例拟实施脊柱手术治疗的老年患者,采用随机数字表法将患者分为对照组、实验组 A (麻醉诱导期及维持期给予右美托咪定 1.0 μg/kg)、实验组 B (麻醉诱导期及维持期给予右美托咪定 2.0 μg/kg)各 30 例;对比两组患者的免疫功能、认知功能指标。结果显示,T_0时刻,3 组患者的血清补体 C3、补体 C4、CD3~+、CD4~+、CD8~+、CD4~+/CD8~+比较,差异均不具有统计学意义(p0.05);在 T_1、T_2时刻,实验组 A、实验组 B 的补体 C3、补体 C4 水平均显著低于空白组(p0.05);在 T_1、T_2时刻,实验组 A、实验组 B的 CD3~+、CD4~+、CD4~+/CD8~+均显著高于空白组(p0.05);术前 1 d,三组患者的 MMSE 评分、血清 S100β蛋白水平比较,差异均不具有统计学意义(p0.05);术后第 1 天,空白组和实验组 A 的 MMSE 评分显著低于实验组 B (p0.05);在术后第 1 天、第 4 天、第 7 天,空白组和实验组 A 的血清 S100β蛋白水平显著低于实验组 B(p0.05)。实施脊柱手术治疗的老年患者麻醉诱导期及维持期给予右美托咪定 1.0 μg/kg,有利于减轻患者的免疫功能损害,同时不会影响患者的认知功能水平。     

不同组分中草药添加剂对三穗鸭血清生化指标的影响

本研究旨在探讨不同营养成分的中草药添加剂对三穗鸭的血清中生化指标的影响。本研究选择健康1日龄三穗鸭300只,随机分为5组,每组60只鸭。对照空白组饲喂普通日粮,试验组分别饲喂普通日粮+1%中草药组分1,普通日粮+1.5%中草药组分1,普通日粮+1%中草药组分2,普通日粮+1.5%中草药组分2。结果表明:对甘油三酯的影响,60日龄和120日龄时试验组C对对照组差异显著(p0.05);对总胆固醇的影响,60日龄和120日龄时实验组C和实验组D对对照组差异显著(p0.05),但相比之下试验组C更显著;对低密度脂蛋白胆固醇的影响,试验组对对照组的差异不显著(p0.05);对高密度脂蛋白胆固醇的影响,60日龄和120日龄时试验组A和试验B对对照组差异显著(p0.05),但相比之下试验组B更为显著。     

Effects of light-emitting diode light v. fluorescent light on growing performance,activity levels and well-being of non-beak-trimmed W-36 pullets

More energy-efficient, readily dimmable, long-lasting and more affordable light-emitting diode (LED) lights are increasingly finding applications in poultry production facilities. Despite anecdotal evidence about the benefits of such lighting on bird performance and behavior, concrete research data were lacking. In this study, a commercial poultry-specific LED light (dim-to-blue, controllable correlated color temperature (CCT) from 4500 to 5300 K) and a typical compact fluorescent light (CFL) (soft white, CCT=2700 K) were compared with regards to their effects on growing performance, activity levels, and feather and comb conditions of non-beak-trimmed W-36 pullets during a 14-week rearing period. A total of 1280-day-old pullets in two successive batches, 640 birds each, were used in the study. For each batch, pullets were randomly assigned to four identical litter-floor rooms equipped with perches, two rooms per light regimen, 160 birds per room. Body weight, BW uniformity (BWU), BW gain (BWG) and cumulative mortality rate (CMR) of the pullets were determined every 2 weeks from day-old to 14 weeks of age (WOA). Activity levels of the pullets at 5 to 14 WOA were delineated by movement index. Results revealed that pullets under the LED and CFL lights had comparable BW (1140±5 g v. 1135±5 g, P=0.41), BWU (90.8±1.0% v. 91.9±1.0%, P=0.48) and CMR (1.3±0.6% v. 2.7±0.6%, P=0.18) at 14 WOA despite some varying BWG during the rearing. Circadian activity levels of the pullets were higher under the LED light than under the CFL light, possibly resulting from differences in spectrum and/or perceived light intensity between the two lights. No feather damage or comb wound was apparent in either light regimen at the end of the rearing period. The results contribute to understanding the impact of emerging LED lights on pullets rearing which is a critical component of egg production.     

Pathogenicity of Eimeria lettyae Ruff, 1985 in the northern bobwhite (Colinus virginianus L.)

Sporulated oocysts of Eimeria lettyae were administered orally to 5-day-old or 18-day-old northern bobwhites (Colinus virginianus, L.). Five-day-old bobwhites were more susceptible based on higher mortality and reduced weight gain. A dose of 5 X 10(5) oocysts produced 25-43% mortality in 5-day-old bobwhites, but none in 18-day-old bobwhites. A dose of 1 X 10(6) oocysts/bobwhite produced 83-100% mortality in 5-day-old bobwhites, and 17-83% mortality in 18-day-old bobwhites. Body weight gain was reduced significantly with a dose of 1 X 10(5) oocysts or greater in 5-day-old bobwhites and with a dose of 5 X 10(5) oocysts or greater in 18-day-old bobwhites. Infection in all age groups reduced concentrations of plasma pigment and plasma protein, but did not affect packed cell volumes. No grossly visible lesions were present in the intestine although there was a shortening of the villi in the duodenum. In mature bobwhites, infection with E. lettyae did not cause mortality, but did reduce egg production and fertility.     

Stimulation with monochromatic green light during incubation alters satellite cell mitotic activity and gene expression in relation to embryonic and posthatch muscle growth of broiler chickens

Previous studies showed that monochromatic green light stimuli during embryogenesis accelerated posthatch body weight (BW) and pectoral muscle growth of broilers. In this experiment, we further investigated the morphological and molecular basis of this phenomenon. Fertile broiler eggs (Arbor Acres, n=880) were pre-weighed and randomly assigned to 1 of the 2 incubation treatment groups: (1) dark condition (control group), and (2) monochromatic green light group (560 nm). The monochromatic lighting systems sourced from light-emitting diode lamps and were equalized at the intensity of 15 lx at eggshell level. The dark condition was set as a commercial control from day 1 until hatching. After hatch, 120 male 1-day-old chicks from each group were housed under incandescent white light with an intensity of 30 lx at bird-head level. No effects of light stimuli during embryogenesis on hatching time, hatchability, hatching weight and bird mortality during the feeding trial period were observed in the present study. Compared with the dark condition, the BW, pectoral muscle weight and myofiber cross-sectional areas were significantly greater on 7-day-old chicks incubated under green light. Green light also increased the satellite cell mitotic activity of pectoral muscle on 1- and 3-day-old birds. In addition, green light upregulated MyoD, myogenin and myostatin mRNA expression in late embryos and/ or newly hatched chicks. These data suggest that stimulation with monochromatic green light during incubation promote muscle growth by enhancing proliferation and differentiation of satellite cells in late embryonic and newly hatched stages. Higher expression of myostatin may ultimately help prevent excessive proliferation and differentiation of satellite cells in birds incubated under green light.     

Modulation of plasma biotin in the fowl (Gallus domesticus) by oestrogen and ambient temperature.

1. Exposure of laying hens to elevated ambient temperatures (30-40 degrees C) resulted in a significant increase in the biotin concentrations in plasma and egg yolk. 2. Exogenous oestrogen administration to immature pullets increased plasma biotin three-fold. The increase was six-fold when the birds were simultaneously exposed to an ambient temperature of 35 degrees C. 3. It is proposed that ambient temperature affects the balance between thyroid and ovarian hormones resulting in increased circulating levels of biotin and deposition of the vitamin in egg yolk.     

A note on light preference in layer pullets reared in incandescent or natural light

The effect of early exposure of pullets to natural light may have an effect on the later preference for light type and on the behaviour of birds after being transferred to laying facilities. Our aim was to study the light-type preference of 14-week pullets reared in either incandescent or natural light. From day-old, a total of 84 LSL chicks were subjected to two light treatments with six groups of seven birds each: 8 h incandescent light + 16 h darkness (I8), and 8 h natural light + 16 h darkness (N8). At the age of 14 weeks, the birds’ light-type preference was tested. Behaviour was recorded at the group level and analysed by a linear mixed model. Predicted mean proportion of birds that chose natural light was 0.36 in N8 and 0.13 in I8 groups. I8 groups showed a preference for incandescent light, in contrast to N8. These results support the notion that pullets for organic egg production shall be reared with access to natural light.     

The effect of light wavelength on the production and quality of eggs of the domestic hen

The effect of light color on egg-laying and on egg quality during the first 50 wk of egg production and during a second cycle of 19 wk following molting was examined. Hens were exposed to one of the following six sources of light: blue (B), green (G), red (R), tungsten (T), cool-white (C) fluorescent or simulated-sunlight (V) fluorescent tubes. Light intensity was equalized at photon output. Total egg production per hen was significantly influenced by the color of light with the most eggs being procuced in R light and the fewest in B light. Hens were more sensitive to light color in response to egg production during the second cycle than during the first cycle. Hens in C light produced significantly fewer eggs than those under V light in both laying cycles. Eggs laid under B or G light were consistently larger than those under R light. Egg weights of hens in V light were heavier than those for the C or T light groups. In the first cycle, shell quality was significantly better in G light than in B or R light. Percent of yolk increased and percent of albumen decreased with age during the first cycle in all treatments and the rate of change was directly related to light color (wavelength). In the second cycle, shell quality, percent of shell, yolk and albumen did not change significantly with age in any of the light treatments. It can be concluded that the wavelength of light may influence egg production, egg components and shell quality of the domestic laying hen.     

Frequency of headshaking in White Leghorn chickens in response to hormonal and environmental changes

Frequency of headshaking in chickens from two selected lines (HA and LA) known to differ in this trait was observed at various ages, during hormonal fluctuations and in different environmental surroundings. Neither hormonal changes concomitant with the initial onset of lay nor ingestion of corticosterone (which stopped egg production in 240-day-old pullets) altered headshaking frequency. When pullets reared in flocks on litter were moved at 77 days of age to individual battery cages, headshaking frequency was dramatically increased in one flock but did not change in another flock. Moving 252-day-old birds from individual cages to floor pens decreased headshaking frequency in males but not in females; returning the birds to cages did not significantly alter levels of headshaking. In older birds (252 days of age), headshaking frequency in all birds in line HA and in males of line LA were considerably greater than in LA females.     

Transitory disturbances in growing lactating rabbits after transient doe-litter separation

To determine the effect of a transient doe-litter separation (48 h) on milk production and feed intake from 1 to 21 days post-partum, a control group (C) in which litters had free access to nursing, and a biostimulated group (B) in which litters were separated from their does from d 9 to d 11 post-partum were used. Total milk production was higher in (C) than in (B) does (5090+/-1.1 g vs. 4593+/-150 g, P < 0.05). On days 12, 13, 14 and 15 of the lactation period, milk production was 40% (P < 0.0001), 18% (P < 0.05), 15% (P < 0.05), and 15% (P < 0.01) higher in (C) than in (B), respectively. No significant differences were observed in feed intake during the period studied (7961+/-352 g in (C) does, and 7834+/-329 g in (B) does). After fasting, 11-day-old kits showed lower gut weight, body weight, empty stomach relative weight (RW), stomach content RW and small intestine RW (P < 0.05), but the differences disappeared at 21 days of age. A reduction in villous height (P < 0.065) was observed in separated kits at 11 days old compared to 9- and 11 -day-old control kits (579.0+/-28.4 vs. 664.64+/-27.6, and 724.33+/-24.1 microm, respectively), but no differences were observed at either 16 or 21 days of age. Specific jejunal lactase activity increased significantly in 11-day-old separated kits (P < 0.05). A significant increase in sucrase activity at 21 days in both groups (P < 0.05) was detected. In conclusion, a fasting period of 48 h at 9 days of age does not compromise the subsequent development of certain digestive parameters of young rabbits.     

Early rearing enrichments influenced nest use and egg quality in free-range laying hens

In Australia, free-range egg production pullets are typically reared indoors, but adult layers get outdoor access. This new environment may be challenging to adapt to, which could impair egg production and/or egg quality. Adaptation might be enhanced through rearing enrichments. We reared 1386 Hy-Line Brown® chicks indoors with three treatments across 16 weeks: (1) a control group with standard litter housing conditions, (2) a novelty group providing novel objects that changed weekly, and (3) a structural enrichment group with custom-designed structures to partially impair visibility across the pen and allow for vertical movement. Pullets were transferred to a free-range system at 16 weeks of age with daily outdoor access provided from 25 until 64 weeks. Daily egg production at different laying locations (large nests, small nests and floor), weekly egg weights and egg abnormalities were recorded from 18 to 64 weeks old. External and internal egg quality parameters of egg weight, shell reflectivity, albumen height, haugh unit, yolk colour score, shell weight and shell thickness were measured at 44, 52, 60 and 64 weeks. There was a significant interaction between rearing treatment and nest box use on hen-day production from weeks 18 to 25 (P < 0.0001) with the novelty hens laying the most eggs and the control hens the fewest eggs in the nest box. Similarly, from 26 to 64 weeks, the novelty hens laid more eggs in the large nest boxes and fewer eggs on the floor than both the structural and control hens (P < 0.0001). Egg weight and abnormalities increased with age (P < 0.0001), but rearing treatment had no effect on either measure (both P ≥ 0.19). Rearing treatment affected shell reflectivity and yolk colour with the control hens showing paler colours across time relative to the changes observed in the eggs from enriched hens. The novelty hens may have established nest box laying patterns as they were more accustomed to exploring new environments. The differences in egg quality could be related to stress adaptability or ranging behaviour. This study shows that enriching environments during rearing can have some impacts on production parameters in free-range hens.     

Intestinal Function and Reproductive Capacity of Tegel pullets in Response to Exogenous Oestrogen

The effects of varying levels of exogenous oestrogen (E₂) (0, 10 or 100µg E₂/kg BW) on the development of 18-week old pullets were tested over a 28-day period. The hormone had no significant effects on feed intake, body growth, feed conversion ratio or weight of the oviduct. Similarly, there were no significant effects of the hormone on egg production and egg weight but eggshell thickness and weight of shell per unit area were increased (P <0.05) at a lower level of administration (10µg E₂/kg BW), compared to the control and the highest level of hormone. The morphometry of the jejunal mucosa and some enzymes associated with Ca transport were similar between the three groups. Oestrogen treatment, however, intensely enhanced the expression of calbindin D_22K, although this was not quantified.