Changes in collagen fiber content and hepatic stellate cell distribution in the liver of chick embryos and growing chickens

The content of collagen and the distribution of hepatic stellate cells (HSCs) were studied to elucidate the occurrence of sex‐dependent variations in the liver of developing embryos and growing chickens. Chick embryos from embryonic days (e) 12 to e20 and chicks at 1, 4 and 8 weeks were analyzed. Liver tissue was processed using NaOH maceration and freeze‐dried to obtain the collagen fiber specimens. HSCs were identified by double fluorescent immunohistochemistry for desmin and vimentin. There were no sex‐dependent variations in the percentage of collagen fiber per liver weight and HSC area during embryonic stages. However, the content of collagen fiber increased during embryonic development in both sexes. On the other hand, the area of HSCs significantly increased in growing males but did not show any change in females. Importantly, sex differences were observed in both collagen fiber content and HSC area in the liver at 8 weeks. These results indicate that the occurrence of collagen content variations takes place at 8 weeks in chicken liver, suggesting that a sex‐dependent hormone may play an important role on the collagen production of HSCs in the growing chicken liver.     

Estradiol inhibits hepatic stellate cell area and collagen synthesis in the chicken liver

Hepatic stellate cells (HSCs) are the main collagen‐producing cells in the liver. The HSC area and amount of collagen fibers are different between male and female chickens. This study was performed to confirm the effect of estradiol on collagen synthesis in the growing chicken liver. Blood estradiol levels in chicks were compared at 4 and 8 weeks of age, and the collagen fibril network in liver tissue was observed at 8 weeks by scanning electron microscopy. Intraperitoneal administrations of estradiol and tamoxifen to male and female chicks, respectively, were performed daily from 5 to 8 weeks of age. The areas of HSCs and collagen contents were measured in the liver tissue. The blood estradiol level was higher in females than in males, and the collagen fibril network was denser in males than in females at 8 weeks of age. Estradiol administration in males induced decreases in the HSC area and collagen content of the liver. Conversely, tamoxifen administration in females induced an increase in the HSC area but did not facilitate collagen synthesis. Based on these results, estradiol inhibits the area and collagen synthesis of HSCs in the growing chicken liver under normal physiological conditions.     

Collagen content and architecture of the pectoralis muscle in male chicks and broilers reared under various nutritional conditions

Varying chicken growth rates were induced with different nutritional regimes, and the collagen content and architecture of M. pectoralis (PT) were compared among 21‐day‐old chicks and broilers at 80 or 95 days of age. The percentage of muscle weight to live weight was higher in rapid growing chicks (8.4%) than slow growing chicks (6.3%). The 80‐day‐old broilers engaged in compensatory growth after the early slow growth period producing PT muscle at 11% of live weight. The 80‐ and 95‐day‐old chicks with restricted late growth after an early rapid growth period showed PT weight at 8% and 9% of live weight, respectively. Collagen content of the PT muscle markedly decreased from the chicks to the broilers. The collagen concentration was higher in the late‐growth restricted broilers (1.67–1.88 mg/g) than the compensatory growth broilers (1.01–1.10 mg/g). Collagen concentration did not differ between the rapid and slow growing chicks (2.72 and 2.94 mg/g). Scanning electron micrographs showed thick and thin perimysia, and honeycomb endomysia. In the perimysia, a stack layer of collagen platelets and a reticular layer of collagen fiber cords were distinguished and collagen baskets of adipocytes were observed. The perimysial collagen fibers became thicker during growth of the chicks to broilers. However, in the late‐growth restricted broilers, the perimysial collagen fibers seemed to have retarded development compared with the compensatory growth birds. The PT muscle of chickens develops optimally when body growth is enhanced. The PT muscle of the compensatory growth broilers had improved collagen architecture regardless of the marked decrease in collagen content.     

不同羽色儋州鸡生长曲线拟合与分析研究

为研究儋州鸡生长发育规律和各阶段的生长速度,本试验采用Gompertz、Logistic和Bertalanffy 3种非线性模型对黑色羽系和麻花色羽系儋州鸡0~18周龄体重生长数据进行拟合和分析,选取黑色羽系、麻花色羽系儋州鸡各200只（公、母各半）,分别于0、2、4、6、8、10、12、14、16和18周龄晨饲前空腹称重并记录,并利用3种非线性模型对儋州鸡生长曲线进行拟合比较分析。结果显示,2种羽色儋州鸡实测生长曲线基本一致,接近于"S"型,符合正常生长发育规律,2种不同羽色儋州鸡母鸡0~18周龄的体重实测值差异不显著（P>0.05）,公鸡0~16周龄的体重实测值差异不显著（P>0.05）,而16~18周龄麻花色羽系公鸡体重显著高于黑色羽系公鸡（P<0.05）。3种非曲线模型拟合度（R²）均在0.992以上,均能较好地拟合2个羽系儋州鸡的生长曲线,且模型的预测曲线与实际观测曲线基本吻合,但Gompertz模型曲线吻合度高于Logistic和Bertalanffy模型曲线,且母鸡比公鸡拟合效果好。本研究结果初步揭示了儋州鸡的生长发育规律和各阶段的生长特征,可为儋州鸡选育、生产和产业化发展提供科学依据。     

麒麟鸡（卷羽鸡）体尺性状与屠宰性能的测定及相关性分析

为了研究抗热应激品种麒麟鸡（卷羽鸡）的肉用开发价值,试验对12周龄麒麟鸡体尺性状和屠宰性能进行测定及相关性分析,并构建简单回归方程。结果表明,12周龄麒麟公鸡龙骨长和胫长显著高于母鸡（P<0.05）;12周龄麒麟公鸡活重、屠体重、半净膛重、全净膛重和腿肌重显著高于母鸡（P<0.05）,腹脂重和皮脂厚显著低于母鸡（P<0.05）,其余指标公、母差异不显著（P＞0.05）;麒麟鸡屠宰性能与体尺性状绝大多数存在显著或极显著相关性,并建立了主要屠宰性状的回归模型,为通过麒麟鸡活体的体尺测量结果预测屠宰性能指标提供一定理论依据,同时加速了麒麟鸡的遗传育种进程。     

Carcase Composition of Taiwan Simulated Native Chickens

This study investigated the carcase composition of Taiwan simulated native chickens at different stages of growth. The results indicated that the carcases of male chickens exhibited significantly larger protein mass and water mass than those of females during weeks 7 to 20; as was the ash mass during weeks 8 to 20. However, the fat mass of the carcases of female chickens was larger than that of males during weeks 14 to 20. Separate regression equations were derived for the relationship between protein mass, fat mass, ash mass and water mass and both carcase weight and age of both male and female chickens.     

雉鸡、吉林本地三黄鸡和肉鸡的肉品质分析研究

为了研究雉鸡、吉林本地三黄鸡和肉鸡之间的肉品质差异,每个品种各选取20只鸡,雌雄各半,在同等条件下进行饲养至出栏日龄。采用常规方法测定不同品种肉鸡的肉品质性状指标,以及肌肉蛋白含量和肌内脂肪含量,利用统计学方法对各品种肉鸡的相关测定指标进行比较分析。结果表明,雄性雉鸡的肌肉系水力最高,与肉鸡、吉林本地三黄鸡差异显著（P<0.05）;雌性雉鸡和肉鸡的肌肉系水力显著（P<0.05）高于吉林本地三黄鸡。雄性和雌性肉鸡的滴水损失率、水浴损失率均显著（P<0.05）高于相应性别的雉鸡和吉林本地三黄鸡。同性别的3个品种鸡的肌肉pH_{24 h}值未表现出品种差异（P>0.05）。同性别的3个品种鸡的肌纤维直径指标表现出显著的品种差异（P<0.05）。雄性雉鸡的肌纤维密度最大,与肉鸡、吉林本地三黄鸡差异显著（P<0.05）;3个品种雌性鸡的肌纤维密度存在显著的种间差异显著（P<0.05）。在肌肉剪切力指标上,雄性吉林本地三黄鸡剪切力最大,与雉鸡、肉鸡差异显著（P<0.05）;雌性雉鸡剪切力最小,三黄鸡剪切力最大,3个品种的雌性鸡剪切力表现出显著的品种差异（P<0.05）。雌性和雄性雉鸡、吉林本地三黄鸡的肌肉蛋白含量显著（P<0.05）高于相应性别的肉鸡。相同性别的3个品种鸡,其肌内脂肪含量之间差异均显著（P<0.05）。综上所述,3个品种鸡的肉品质指标以及肌肉蛋白含量和肌内脂肪含量存在差异,雉鸡、吉林本地三黄鸡肉品质优于肉鸡,可作为本地饲养的首选品种。     

如皋鸡生长发育规律和体尺性状研究

本试验对0～12周龄如皋鸡的体重生长规律及12周龄体尺性状进行了研究。结果表明：①1～12周龄公母鸡间体重存在极显著差异（P<0.01），公鸡的体重整齐度较差；②Gompertz模型能很好地描述鸡体重生长模式（R2＞0.996）,其生长拐点在6～7周龄，如皋鸡成熟体重和生长高峰体重的遗传力均为0.09，初生重估计值、平均生长速率、生长高峰周龄的遗传力分别为0.21、0.32、0.37；③用全同胞和半同胞2种遗传模型估计的体重方差组分及遗传力结果有明显差异。用全同胞遗传模型计算的公鸡体重遗传力明显高于母鸡（都是高遗传力），体重遗传力总体上随饲养周龄的增长呈下降趋势，随周龄增加母本效应越来越小，并且公鸡受母本效应的影响明显大于母鸡，用半同胞遗传模型计算的公鸡体重遗传力7周龄前小于母鸡，8～9周龄等于母鸡，10～12周龄大于母鸡；④12周龄体尺性状中除胸角性别间差异不显著（P>0.05）、公鸡胫色显著黄于母鸡（P<0.05）外，其他性状均为公鸡极显著大于（红于）母鸡（P<0.01）；⑤12周龄胸角与其它体尺性状表型相关都不显著（P>0.05），其余绝大部分性状间存在显著（P<0.05）或极显著（P<0.01）相关。⑥活重、体斜长、龙骨长、胫长、胫围、冠长、冠高、冠色、胫色、胸角、胸宽的遗传力分别为0.53、0.11、0.64、0.92、0.42、0.16、0.15、0.52、0.25、0.16、0.40。     

持续高温对不同性别北京油鸡脂肪代谢及血液脂肪细胞因子水平的影响

本研究旨在考察持续高温对不同性别北京油鸡脂肪代谢及血液脂肪细胞因子水平的影响.选择健康、体重相近的49日龄北京油鸡公母各72只[公鸡平均体重(608.58±13.07)g;母鸡平均体重(518.50±8.33)g],随机分在2个处理中:高温组,(35.00±0.37)℃;适温组,(25.00±0.38)℃,每个处理设6个重复,每个重复6只鸡.试验持续23 d.测定试验第12、23天时的血液生化指标、血液脂肪细胞因子水平及脂肪组织脂蛋白酯酶活性.结果表明:1)对公鸡而言:持续高温12 d时血清胰岛素水平显著升高(P＜0.01),血浆甘油三酯含量显著降低(P＜0.01).持续高温23 d时血清胰岛素水平和血浆甘油三酯含量显著降低(P＜0.01),血浆葡萄糖含量显著升高(P＜0.01);对母鸡而言:持续高温12 d时血浆甘油三酯、游离脂肪酸含量显著降低(P＜0.05).持续高温23 d时血浆甘油三酯、游离脂肪酸含量无显著变化(P＞0.05),血浆极低密度脂蛋白含量有增加趋势(P =0.065),血浆葡萄糖含量显著升高(P＜0.01).2)持续高温12 d时公母鸡的肌间脂肪脂蛋白酯酶活性都显著降低(P＜0.05),持续高温23 d时公鸡的肌间脂肪脂蛋白酯酶活性显著降低(P＜0.05),而母鸡的无显著变化(P＞0.05).3)公母鸡血浆脂联素、抵抗素水平在高温下都无显著变化(P＞0.05);持续高温12 d时公鸡血浆瘦素水平显著降低(P＜0.01),母鸡的显著升高(P＜0.05).由此可知,随着持续高温时间的延长,母鸡血浆游离脂肪酸、甘油三酯含量及肌间脂肪组织脂蛋白酯酶活性受高温影响下降程度减小,公鸡血浆甘油三酯含量及脂肪组织脂蛋白酯酶活性下降程度加大.     

贵州黄鸡慢羽系生长曲线拟合研究

试验旨在揭示贵州黄鸡慢羽系生长发育规律。选择100只贵州黄鸡慢羽系（公母鸡各50只），于0、2、4、6、8、10、12、14周龄末称重，分别采用Bertalanffy、Logistic、Gompertz 3种非线性生长曲线模型对贵州黄鸡慢羽系0~14周龄体重变化进行拟合分析。结果表明：3种模型均能很好地拟合其生长曲线，拟合度均在0.99以上，其中Logistic模型在贵州黄鸡慢羽系公鸡、母鸡生长曲线中拟合最好，拟合结果最接近实测体重情况，其公鸡拐点体重为1 550.81 g，拐点周龄为10.42，母鸡拐点体重为976.67 g，拐点周龄为9.14。试验结果初步揭示了贵州黄鸡慢羽系的生长发育规律和各阶段的生长特征，为贵州黄鸡慢羽系选育生产和产业化发展提供了科学依据。     

饲养密度和高蛋白质饲粮代谢能水平对公母分饲肉鸡生长性能和腿部健康的影响

本试验旨在研究饲养密度与高蛋白质(前期23%,后期21%)饲粮代谢能水平对公母分饲肉鸡生长性能和腿部健康的影响。试验采用2(性别)×2(饲养密度)×3(饲粮代谢能水平)三因子完全随机设计,选用1日龄罗斯308(Ross 308)肉鸡公雏1 872只和母雏2 160只,随机分成12个组,每组8个重复。试验设高、低2个饲养密度,以出栏体重计,分别为42[高饲养密度(HSD),16公/m2或18母/m2]和26 kg/m2[低饲养密度(LSD),10公/m2或12母/m2]。试验饲粮分前期(1~21日龄)和后期(22~35日龄)2个阶段配制,饲粮代谢能设高、中、低3个水平,其中,高代谢能(HME)水平饲粮前期和后期的代谢能水平分别为12.81和13.23 MJ/kg,中代谢能(MME)水平饲粮前期和后期的代谢能水平分别为12.18和12.60 MJ/kg,低代谢能(HME)水平饲粮前期和后期的代谢能水平分别为11.55和11.97 MJ/kg。结果表明:1)饲养密度与饲粮代谢能水平对肉鸡的平均日增重和料重比有显著交互作用(P0.05)。1~21日龄时,随着饲粮代谢能水平增加,HSD组平均日增重的增加幅度和料重比的降低幅度均小于LSD组;22~35日龄时结果正好相反。性别与饲养密度对肉鸡的平均日采食量有显著交互作用(P0.05)。随着饲养密度增加,公鸡平均日采食量的降低幅度大于母鸡。2)HSD极显著降低肉鸡的胸肌率(P0.01),母鸡的胸肌率和腹脂率显著高于公鸡(P0.05)。饲粮代谢能水平和饲养密度对肉鸡的腿肌率有显著交互作用(P0.05)。随着饲粮代谢能水平增加,LSD组肉鸡的腿肌率降低,而HSD组基本不变。3)高饲粮代谢能水平极显著降低肉鸡的脚垫损伤评分(P0.01),公鸡的步态评分和脚垫损伤评分显著高于母鸡(P0.05),垫料水分含量显著低于母鸡(P0.05)。饲粮代谢能水平与饲养密度对肉鸡的脚垫损伤评分有显著交互作用(P0.05)。随着饲粮代谢能水平增加,HSD组脚垫损伤评分的降低幅度大于LSD组。以上结果表明,高饲养密度降低肉鸡的平均日增重,增加料重比;35日龄前,公鸡比母鸡的空间需求更高;提高高蛋白质饲粮的代谢能水平可以缓解HSD对肉鸡生长性能和脚垫健康的不利影响。     

无量山乌骨鸡体重和体尺测定及相关性分析

目的 研究不同性别无量山乌骨鸡体重、屠体重和体尺的相关性。方法 以18周龄无量山乌骨鸡为研究对象,测定公母各30只鸡体重、屠体重以及体斜长、龙骨长、胫长、胫围、髋宽、胸宽和胸深,应用独立样本t检验进行比较,采用Pearson分析法进行相关性分析。结果 无量山乌骨鸡公鸡体重、屠体重、体斜长、龙骨长、胫长、胫围、髋宽、胸宽和胸深极显著（P<0.01）高于母鸡。公鸡体重与屠体重、龙骨长和胫围极显著（P<0.01）正相关。母鸡体重与屠体重极显著（P<0.01）正相关,与胫围显著（P<0.05）正相关。结论 公鸡体重和体尺显著高于母鸡;体重与屠体重和胫围显著正相关;骨骼发育相关的龙骨长、胫长和胫围等体尺指标存在相关性。     

拜城油鸡与良凤花鸡杂交后代(F3A型)屠宰性能及肉品质分析

利用拜城油鸡公鸡与良凤花母鸡杂交一代(F_1),再利用拜城油鸡的公鸡与F_1中的青脚母鸡级进杂交,得到F_2代,选取F_2代的青脚母鸡与F_2代的高脚公鸡进行横交,得到油麻鸡F_3A型,测定其公、母鸡的屠宰性能与肉品质指标。结果表明:F_3A型公、母鸡的屠宰率、半净膛率、全净膛率分别比拜城油鸡公、母鸡提高6.73%(P<0.01)、5.8%(P<0.05)、2.82%(P>0.05)和4.42%(P<0.05)、4.22%(P<0.05)、1.65%(P>0.05);公、母鸡胸肌肉色分别比良凤花鸡提高7.31和11.08,公、母鸡腿肌肉色比良凤花鸡提高21.23和16.88;公、母鸡胸肌滴水损失分别比良凤花鸡提高1.26%(P<0.01)和4.73%(P<0.01)。拜城油鸡与良凤花鸡杂交后,杂交后代的屠宰性能有明显改善,肉品质指标亦有相应变化。     

不同杂交组合优质冷鲜鸡屠宰性能和肉品质比较

培育适合屠宰加工的早熟、青脚、优质肉鸡新品系,通过比较63日龄ABC、ABD和AEB杂交组合鸡群的屠宰性能和肉品质,初步筛选最优杂交组合。结果表明:3个杂交组合63日龄母鸡体重均超过1.8 kg,公鸡体重均超过2.2 kg;公母鸡的屠宰率均超过86%,全净膛率均超过68%;ABC母鸡的全净膛率、胸肌率均显著高于其他杂交组合(P0.05);ABC组合母鸡的腹脂率显著低于其他2个组合(P0.05);ABC和ABD组合公母鸡胸肌肌苷酸含量显著高于AEB母鸡肌苷酸含量(P0.05);ABC公母鸡肌内脂肪含量显著高于ABD母鸡、AEB公鸡(P0.05);3个杂交组合组合间、组合内及公母间屠宰性能(失水率、剪切力和p H)均差异不显著。ABC公母鸡胸肌肉色L值显著高于其他2个杂交组合(P0.05);ABC母鸡肉色a值显著低于AEB(P0.05)。通过对3个杂交组合屠宰性能和肉品质的比较,发现ABC组合的屠宰率、全净膛率、胸肌率、肌苷酸含量、肌内脂肪含量和肉色相对较好,初步确定ABC组合最佳,为下一步优质冷鲜鸡的新品系培育奠定基础。     

Dynamics of yolk sac resorption and post-hatching development of the gastrointestinal tract in chickens, ducks and geese

Under similar environmental conditions, 100 male Shaver-Starbro hybrid chickens, 100 male Mulard cross-line ducklings and 100 male Landaise goslings kept in 30 metabolic cages from the first day of life (10 birds of each species separately per cage) were chosen for the study. The animals were fed semi ad libitum diets with crude protein content and energy density similar to that used for poultry species, avoiding feed residues. During the first 21 days of life they received starter diets and from day 22 to 42 grower diets. Maize accounted for 23-40% and barley constituted 10-18%. Wheat accounted for 20.0% in starter diets and 10-18% in grower diets. Resorption of yolk sac residues, performance, development of the intestinal tract in young chickens, ducklings and goslings were assessed. During the first 5 days of life intensive absorption of yolk sac ingredients was observed. On day 7, residues of the yolk sac were found in more than 30% of chickens compared with approximately 10% in geese. In ducklings residues of the yolk sac were not found. On day 16 unabsorbed yolk sacs were found in approximately 10% of chickens. Liver and pancreas weighed the highest in geese and in ducks; in chickens the weight of these organs was significantly lower (p < 0.01). The relative values calculated to 100 g of metabolic body weight show that the average small intestine in chickens was significantly longer (p < 0.01) than in ducks or geese. The intestinal tract developed earlier in the chicken than in the water fowl.     

抗菌肽制剂对芦花鸡胸肌肉质性状、游离氨基酸及微量元素含量的影响

本文旨在探讨抗菌肽制剂对芦花鸡胸肌肉质性状、游离氨基酸及微量元素含量的影响.试验采用单因子设计方案,选取1日龄健康芦花鸡450只,随机分为3组,每组3个重复,每个重复50只鸡(公母各占1/2).Ⅰ组(对照组)饲喂基础饲粮,Ⅱ、Ⅲ组分别饲喂在基础饲粮中添加抗菌肽及抗菌肽+酵母菌制剂的试验饲粮,试验期90 d.结果表明:1)Ⅱ、Ⅲ组芦花鸡胸肌滴水损失较Ⅰ组有降低趋势,但差异不显著(P＞0.05),肌纤维直径均较Ⅰ组极显著降低(P＜0.01).Ⅱ组肌纤维密度较Ⅰ组显著提高(P＜0.05),Ⅲ组较Ⅰ组极显著提高(P＜0.01).2)Ⅱ、Ⅲ组胸肌必需氨基酸含量和游离氨基酸总量与对照组无显著差异(P＞0.05).3)Ⅱ、Ⅲ组胸肌硒含量均较Ⅰ组有极显著的提高(P＜0.01),Ⅲ组亦显著提高了锰含量(P＜0.05),对其他微量元素含量无显著影响(P＞0.05).综上所述,抗菌肽+酵母菌制剂对芦花鸡胸肌肉质性状、游离氨基酸及微量元素含量的作用效果较好,且优于单独使用抗菌肽.     

Immunohistochemical and ultrastructural study of ito cells (fat-storing cells) in response to extrahepatic bile duct ligation in broiler chickens.

The Ito cell (fat-storing cell) lies in perisinusoidal space of liver and has a variety of functions. We investigated the immunohistochemistry and ultrastructure of Ito cells in normal and cholestatic livers of broiler chickens. Immunohistochemistry demonstrated that Ito cells expressed HHF35 muscle actin, vimentin, desmin, glial fibrillary acidic protein (GFAP), neuron-specific enolase (NSE), chromogranin A and cytokeratins in normal livers. These cells were diffusely scattered throughout the lobules. Livers treated with extrahepatic bile duct ligation (BDL) showed cholestasis, fibrosis, proliferation of biliary ductules and Ito cells. The Ito cells were frequently found in fibrotic areas and were larger in size with more extensive immunoreactivity than those of normal livers. Ultrastructural study demonstrated that Ito cells were closely associated with the production of collagen fibers in BDL livers. These findings suggest that Ito cells actively react against hepatocytic injuries and play a major role in the hepatic fibrogenesis of cholestatic livers of chickens.     

Effects of Estradiol on Expression of Estrogen Receptor and Collagen mRNAs in Chick Skin

Skin thickness and strength differ between male and female chickens. This study aimed to clarify the effects of estradiol on the expression of estrogen receptors and collagen mRNA in chicken skin. Estradiol was administered to male chicks for 3 weeks, then cryosections of skin collected from the cervical, thoracic, dorsal, and pelvic limb regions were stained with hematoxylin and eosin, and dermal thickness was measured. Estrogen receptor and collagen mRNA expression was assessed using real-time RT-PCR, and collagen contents were determined. Estradiol did not alter dermal thickness or the collagen content of the skin from any tested region. Among the estrogen receptors, significantly more ESR1 mRNA was expressed in the thoracic skin of chicks administered with estradiol compared with vehicle (control), and in the thoracic skin compared with skin from other regions within each group. Estradiol did not affect ESR2, GPER, and COL1A1 mRNA expression. These results suggested that estradiol stimulates ESR1 expression in thoracic skin, but does not affect collagen synthesis in skin from any other region of male chicks.     

去势对鸡肉品质及风味的影响

通过比较不同鸡品种去势及未去势鸡肉pH值、剪切力及肉品风味,研究去势对鸡肉肉质和风味的影响。试验结果表明,无论是白来航还是寿光鸡,去势鸡肉质感官综合评定结果均优于未去势鸡。这表明去势改善了鸡肉风味,使之更加鲜嫩多汁,富有口感。     

Gender,caponization and exogenous estrogen effects on lipids,bone and blood characteristics in Taiwan country chickens

This study investigated gender, caponization and exogenous estrogen effects on lipids, bone and blood characteristics in Taiwan country chickens. Thirty male chickens were caponized at 8 weeks (capons); 15 capons were injected with estrogen (5 mg/bird estradiol 3‐benzoate) every 2 weeks from 8 to 28 weeks, and 15 sham‐operated male (shams) chickens and 15 females were selected for this trial. The results showed that the shams had lower relative abdominal and chest subcutaneous fat than females (P < 0.05). The estrogen‐treated capons had greater relative abdominal and chest subcutaneous fat than shams and capons (P < 0.05), which might result from higher blood very low‐density lipoproteins and triacylglycerol concentrations (P < 0.05). Caponization could dramatically increase relative abdominal fat (506%; P < 0.05). The shams had higher tibia weight and biomechanical properties, such as maximum bone strength and bending moment values than the capons (P < 0.05). Tibia biomechanical properties were reduced by estrogen treatment (P < 0.05). The females obtained the lowest biomechanical value in all treatments (P < 0.05). Histological examination revealed cavity formation in the cortical bone of estrogen‐treated capons and female chickens, which suggested that estrogen reduced bone biomechanical properties by destroying its structural integrity.