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.     

Effects of caponization on fat metabolism–related biochemical characteristics of broilers

A two‐trial experiment was conducted to evaluate the effects of caponization on fat metabolism‐related biochemical characteristics of broilers. Male Redbro broilers were purchased, caponized at 3 weeks and reared until either the 18th (Trial 1) or the 24th (Trial 2) week. In Trial 1, five slaughters were performed at 6, 9, 12, 15 and 18 weeks of age while in Trial 2 one slaughter at the end of the experiment (24 weeks). In each slaughter, the abdominal adipose tissue cellularity, the NADP dehydrogenase activity in the liver and some serum lipoproteins concentrations were assessed. Caponization had a marked effect on the adipocyte volume and NADP‐malate dehydrogenase activity in the liver at 24 weeks but it did not affect adipocyte number or the activity of NADP‐isocitrate dehydrogenase activity at any age (p < 0.05). Regarding the lipoproteins, cholesterol and HDL‐cholesterol were elevated in capon serum at 18 weeks of age while no difference was detected in the triglyceride concentration at any age. In conclusion, a relationship between fat deposition at the phenotypic level and the level of lipogenic enzymes and lipoproteins capons was established but not as pronounced as expected as some parameters displayed a constant increasing pattern while others did not.     

促黄体素释放激素（LRH）抗原对公雏免疫去势效果的研究

制备促黄体素释放激素（ＬＲＮ）抗原乳剂，给１０日龄公雏注射后，每周称体重，测鸡冠厚、高、长度，第２０周屠宰，称们体重及睾丸重。试验结果表明，ＬＲＨ抗原无论加入弗氏佐剂或氢氧（也铝佐剂，只要达到一定注射剂量（首次量１０μｇ／只，二次量加倍），就可产生明显的免疫去势效果，即鸡冠及睾九生长变慢，试验组与对照组比较差异十分显著（Ｐ＜０．０１）；体重增长加快，试验组与对照组比较，在第４、８、２０周平均体重和宰后胴体重差异十分显著（Ｐ＜０．０１）或显著（Ｐ＜０．０５）。而ＬＲＨ首次注射剂量为５μｇ／只的试验组与对照组比较，上述各项指标均无显著差异（Ｐ＞０．０５）。