本研究旨在考察持续高温对不同性别北京油鸡生长性能、肉质性状及脂肪沉积的影响.选择健康、体况相近的49日龄北京油鸡公母各72只(公鸡平均体质量(608.58±13.07)g;母鸡平均体质量(518.50±8.33)g)随机分在2个处理中:(1)高温组,(35±0.37)℃;(2)适温组,(25±0.38)℃,分别在2个人工环境气候舱中饲养.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1～11、12～22和1～22天的生产性能指标及第12和23天时的胴体性状、肉质性状及脂肪沉积率.结果表明；1)热暴露1～11 d,公母鸡的日增体质量都显著降低(P＜0.01),料重比无明显变化(P＞0.05).热暴露12～22 d,公鸡的日增体质量显著降低(P＜0.01),而母鸡无明显变化(P＞0.05),同时,公鸡的料重比显著提高(P＜0.01);2)与适温组相比,高温组各性别北京油鸡的肉质性状均无明显变化(P＞0.05)；3)对公鸡而言,热暴露12 d时腹脂、肌间脂肪和皮下脂肪沉积率及胴体率、腿比率与适温组相比均无显著差异(P＞0.05).热暴露23 d时各部位脂肪沉积率均显著降低(P＜0.01),而胴体率和腿比率显著提高(P＜0.05)；对母鸡而言,热暴露12d时腹脂、肌间脂肪沉积率显著降低(P＜0.05),热暴露23 d时皮下脂肪率显著降低(P＜0.05),腹脂、肌间脂肪沉积率及胴体率、腿比率与适温组相比均无显著差异(P＞0.05).结果提示,热暴露12 d,各性别油鸡的日增体质量均显著降低,随着热暴露进一步延续,公鸡日增体质量的降低幅度加大,而母鸡的已无明显变化；随着热暴露时间的延长,公鸡的脂肪沉积逐渐下降,而母鸡的脂肪沉积下降程度有所缓解.%The current study was conducted to investigate the effects of chronic heat exposure on growth performance, meat quality and fat deposition in Beijing-You (BJY) chickens. One hundred and forty-four 49-day-old healthy BJY chickens (72 males and 72 females) with similar body weight (male (608. 58± 13. 07)g, female (518. 50±8. 33)g) were randomly assigned into two treatments(high-temperature group(35±0. 37)℃ .optimal-temperature group(25±0. 38)℃) with 6 replicates in each treatment and 6 birds in each replicate. The experiment lasted for 23 d. The growth performance (1-11,12-22 and 1-22 d) and the carcass traits, meat quality and fat deposition on 12 and 23 d of BJY chickens were assayed. The result showed as followed) 1) During 1-11 d, male and female weight gain was significantly decreased by heat exposure (P<0. 01), but the ratio of feed to gain was not affected (P>0. 05). During 12-22 d, heat exposure depressed weight gain of male (P<0. 01), and ratio of feed to gain of males increased by heat exposure (P< 0. 01); 2) Meat quality of males and females were not affected by heat treatment (P>0. 05); 3) For males, abdominal, intramuscular and subcutaneous fat deposition, carcass proportion, and leg weight proportion were not affected by heat exposure on 12 d (P>0. 05). Whereas, on 23 d, abdominal, intramuscular and subcutaneous fat deposition markedly decreased by heat exposure (P<0. 01), but carcass proportion and leg weight proportion increased (P<0. 05). For females, abdominal and intramuscular fat deposition decreased by heat exposure on 12 d (P<0. 05). On 23 d, heat exposure decreased subcutaneous fat deposition (P<0. 05), and abdominal and intramuscular fat deposition, carcass proportion, and leg weight proportion were not affected by heat treatment (P>0. 05). These results suggest that 12 d heat exposure significantly depressed male and female weight gain. With the prolonged exposure time, weight gain of males decreased more severely, but females were not significantly affected, and fat deposition of males gradually decreased, but decreasing degree in females were relieved.
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