Departamento de Produção Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista, Botucatu, SP, Brazil.
Animal. 2013 Mar;7(3):518-23. doi: 10.1017/S1751731112001838. Epub 2012 Oct 1.
Rabbits are very sensitive to heat stress because they have difficulty eliminating excess body heat. The objective of the current study was to evaluate the effects of heat stress on slaughter weight, dressing percentage and carcass and meat quality traits of rabbits from two genetic groups. Ninety-six weaned rabbits were used: half were from the Botucatu genetic group and half were crossbreds between New Zealand White sires and Botucatu does. They were assigned to a completely randomized design in a 2 × 3 factorial arrangement (two genetic groups and three ambient temperatures: 18°C, 25°C and 30°C) and kept under controlled conditions in three environmental chambers from 5 to 10 weeks of age. Slaughter took place at 10 weeks, on 2 consecutive days. Meat quality measurements were made in the longissimus muscle. Actual average ambient temperature and relative humidity in the three chambers were 18.4°C and 63.9%, 24.4°C and 80.2% and 29.6°C and 75.9%, respectively. Purebred rabbits were heavier at slaughter and had heavier commercial and reference carcasses than crossbreds at 30°C; however, no differences between genetic groups for these traits were found at lower temperatures. No genetic group × ambient temperature interaction was detected for any other carcass or meat quality traits. The percentages of distal parts of legs, skin and carcass forepart were higher in crossbred rabbits, indicating a lower degree of maturity at slaughter in this group. The percentage of thoracic viscera was higher in the purebreds. Lightness of the longissimus muscle was higher in the purebreds, whereas redness was higher in the crossbreds. Slaughter, commercial and reference carcass weights and the percentages of thoracic viscera, liver and kidneys were negatively related with ambient temperature. Commercial and reference carcass yields, and the percentage of distal parts of legs, on the other hand, had a positive linear relationship with ambient temperature. Meat redness and yellowness diminished as ambient temperature increased, whereas cooking loss was linearly elevated with ambient temperature. Meat color traits revealed paler meat in the purebreds, but no differences in instrumental texture properties and water-holding capacity between genetic groups. Purebred rabbits were less susceptible to heat stress than the crossbreds. Heat stress resulted in lower slaughter and carcass weights and proportional reductions of organ weights, which contributed to a higher carcass yield. Moreover, it exerted a small, but negative, effect on meat quality traits.
兔子对热应激非常敏感，因为它们很难消除多余的体热。本研究的目的是评估热应激对来自两个遗传群体的兔子的屠宰体重、屠宰率和胴体及肉质特性的影响。使用了 96 只断奶兔：一半来自博图卡图遗传群体，另一半是新西兰白兔公兔与博图卡图母兔的杂交后代。它们被分配到一个完全随机的设计，在 2 × 3 因子安排（两个遗传群体和三个环境温度：18°C、25°C 和 30°C）中，并在三个环境室中从 5 到 10 周龄保持在受控条件下。在 10 周龄时进行屠宰，连续两天进行。在背最长肌中进行肉质测量。三个室中的实际平均环境温度和相对湿度分别为 18.4°C 和 63.9%、24.4°C 和 80.2%以及 29.6°C 和 75.9%。在 30°C 时，纯种兔的屠宰体重较重，商业和参考胴体较重，而在较低温度下，两个遗传群体之间的这些性状没有差异。对于任何其他胴体或肉质特性，未检测到遗传群体×环境温度的互作。杂交后代的腿部远端部分、皮肤和胴体前部的比例较高，表明该组在屠宰时成熟度较低。纯种的胸腔脏器比例较高。背最长肌的亮度在纯种中较高，而杂交后代的红色度较高。背最长肌的亮度在纯种中较高，而杂交后代的红色度较高。屠宰、商业和参考胴体重量以及胸腔脏器、肝脏和肾脏的百分比与环境温度呈负相关。商业和参考胴体产率以及腿部远端部分、的比例与环境温度呈正线性关系。随着环境温度的升高，肉的红色度和黄色度降低，而烹饪损失则随环境温度线性升高。肉色性状显示纯种的肉色较浅，但遗传群体之间的仪器质地特性和持水性没有差异。纯种兔比杂交后代对热应激的敏感性较低。热应激导致屠宰体重和胴体重量降低，以及器官重量的比例降低，从而提高胴体产率。此外，它对肉质特性产生了较小的负面影响。
