Faculty of Agricultural and Environmental Sciences, Kaposvár University, Guba S. Str.,40, H-7400 Kaposvár, Hungary.
Faculty of Agricultural and Environmental Sciences, Kaposvár University, Guba S. Str.,40, H-7400 Kaposvár, Hungary.
Animal. 2021 Feb;15(2):100096. doi: 10.1016/j.animal.2020.100096. Epub 2020 Dec 23.
Rabbits are particularly sensitive to heat stress which can affect productive performance, with rabbit breed/line possibly playing a role on the response to this condition. The study aimed at evaluating the effect of different ambient temperatures on the live performance and carcass traits of growing rabbits divergently selected for total body fat content. The two genetic lines (Lean and Fat) were selected based on the total body fat content estimated by computer tomography during five generations. From birth to slaughter (13 weeks of age), the rabbits were housed in two rooms where the temperature was controlled with air conditioners: in the control room the average ambient temperature was 20 °C and in the high temperature room it was 28 °C. After weaning (35 d), 60 Lean and 60 Fat rabbits/room were housed by two in wire-mesh cages and fed ad libitum with commercial pellets. The BW and feed intake (FI) were measured at 5, 7, 9, 11 and 13 weeks of age to calculate the daily weight gain (DWG) and feed conversion ratio (FCR). Mortality was recorded daily. At the end of the experiment, rabbits were slaughtered and carcass traits were measured. Mortality was independent of temperature and line. The temperature significantly influenced the FI, DWG, BW and the fat deposits: they were lower at higher ambient temperature. The effect of temperature differed according to the rabbits' total body fat content. At control temperature, the FI (165 vs 155 g/day; P < 0.05) and FCR (4.67 vs 4.31; P < 0.05) were higher in Fat rabbits, which also had more perirenal (36.2 vs 23.1 g; P < 0.05) and scapular fat (10.8 vs 7.1 g; P < 0.05). At high temperature, no differences in fat depots (14.5 vs 9.8 g; 5.3 vs 3.5 g) were found between the two lines. It can be concluded that temperature × genetic line interaction had an important role in productive and carcass traits, as the effect of temperature differs between Lean and Fat rabbits.
兔子对热应激特别敏感，这会影响生产性能，而兔子品种/系可能在对这种情况的反应中发挥作用。本研究旨在评估不同环境温度对通过计算机断层扫描（CT）在五个世代中估计的总体脂肪含量进行差异选择的生长兔的活体性能和胴体性状的影响。根据总体脂肪含量，从出生到屠宰（13 周龄），通过计算机断层扫描（CT）在两个房间中饲养这两个遗传系（瘦系和胖系）：在对照房间中，环境温度平均为 20°C，在高温房间中，环境温度为 28°C。断奶后（35 天），每个房间中饲养 60 只瘦系和 60 只胖系兔子，每两只兔子放在一个金属丝笼中饲养，并自由采食商业颗粒饲料。在 5、7、9、11 和 13 周龄时测量体重和饲料摄入量（FI），以计算日增重（DWG）和饲料转化率（FCR）。每天记录死亡率。实验结束时，屠宰兔子并测量胴体性状。死亡率与温度和系别无关。温度显著影响 FI、DWG、BW 和脂肪沉积：在较高的环境温度下，FI、DWG、BW 和脂肪沉积较低。温度的影响根据兔子的总体脂肪含量而不同。在对照温度下，胖系兔子的 FI（165 比 155g/天；P<0.05）和 FCR（4.67 比 4.31；P<0.05）更高，肾周脂肪（36.2 比 23.1g；P<0.05）和肩胛部脂肪（10.8 比 7.1g；P<0.05）也更多。在高温下，两个系之间的脂肪沉积（14.5 比 9.8g；5.3 比 3.5g）没有差异。可以得出结论，温度×遗传系互作对生产性能和胴体性状有重要作用，因为温度对瘦系和胖系兔子的影响不同。
