Fanatico A C, Pillai P B, Emmert J L, Owens C M
Center for Excellence in Poultry Science, University of Arkansas, Fayetteville 72701, USA.
Poult Sci. 2007 Oct;86(10):2245-55. doi: 10.1093/ps/86.10.2245.
Consumer interest in free-range and organic poultry is growing. Two concurrent experiments were conducted to assess 1) the impact of alternative genotype and production system and 2) the impact of genotype and diet on meat quality of chickens for specialty markets. Specifically, a slow-growing genotype (slow) and a fast-growing genotype (fast) were raised for 91 and 63 d (females), respectively, or 84 and 56 d in the case of the second trial (males). In each trial, the slow birds were placed before the fast birds to achieve a similar final BW at processing. Each genotype was assigned to 4 pens of 20 birds each and raised in indoor floor pens in a conventional poultry research facility; each genotype was also assigned to 4 floor pens in a small facility with outdoor access. A low-nutrient diet was used, formulated for a slower rate of production. Birds were commercially processed and deboned at 4 h postmortem. In the second trial, the diets compared were a conventional diet that met NRC requirements or the low-nutrient diet, and all birds were raised indoors. There was an interaction between genotype and production system for the color (b*; P < 0.05). The meat and skin of the slow birds became more yellow when the birds had outdoor access; however, this did not occur when the fast birds had outdoor access. The breast meat of the slow birds had more protein and alpha-tocopherol (P < 0.05) than the fast birds and half the amount of fat (P < 0.05). In addition, the meat of the outdoor birds had more protein than the indoor birds (P < 0.05). The slow birds had poorer water-holding capacity but were more tender than the fast birds (P < 0.05). The type of diet had little impact on meat quality. These data indicate that meat quality differences exist between genotypes with different growth rates and raised in alternative production systems.
消费者对散养和有机家禽的兴趣日益增长。进行了两项并行实验,以评估:1)替代基因型和生产系统的影响;2)基因型和日粮对特种市场鸡肉肉质的影响。具体而言,慢速生长基因型(慢型)和快速生长基因型(快型)的鸡分别饲养91天(雌性)和63天,或在第二项试验中(雄性)饲养84天和56天。在每项试验中,慢型鸡比快型鸡先入栏,以便在屠宰时达到相似的最终体重。每种基因型被分配到4个栏舍,每个栏舍饲养20只鸡,在传统家禽研究设施的室内地面栏舍中饲养;每种基因型还被分配到一个有户外通道的小型设施中的4个地面栏舍。使用了一种低营养日粮,其配方旨在实现较慢的生产速度。鸡在屠宰后4小时进行商业加工并去骨。在第二项试验中,比较的日粮是符合美国国家研究委员会(NRC)要求的常规日粮或低营养日粮,所有鸡均在室内饲养。颜色(b*;P<0.05)方面,基因型和生产系统之间存在交互作用。当慢型鸡有户外通道时,其肉和皮肤会变得更黄;然而,当快型鸡有户外通道时,情况并非如此。慢型鸡的胸肉比快型鸡含有更多的蛋白质和α-生育酚(P<0.05),脂肪含量只有快型鸡的一半(P<0.05)。此外,户外饲养的鸡的肉比室内饲养的鸡含有更多的蛋白质(P<0.05)。慢型鸡的保水能力较差,但比快型鸡更嫩(P<0.05)。日粮类型对肉质影响不大。这些数据表明,不同生长速度的基因型以及在不同生产系统中饲养的鸡之间存在肉质差异。