Department of Animal Wealth Development, Faculty of Veterinary Medicine, Zagazig University, El-Zeraa str. 114, Zagazig, 44511, Sharkia, Egypt.
Biological Applications Department, Radioisotopes Applications Division, NRC, Atomic Energy Authority, Inshas, Cairo, Egypt.
Trop Anim Health Prod. 2021 Jul 9;53(3):393. doi: 10.1007/s11250-021-02842-9.
The objective of this work was to elucidate the impact of cage density on growth efficiency, carcass yield, and muscle amino acid profile of fattening rabbits. In total, 96 weaned rabbits were assigned into three cage densities: low cage density (LCD) = 1425 cm/rabbit; medium cage density (MCD) = 850 cm/rabbit; high cage density (HCD) = 625 cm/rabbit. Compared with the HCD, the body gain and feed conversion ratio were better in the LCD and MCD groups (P = 0.003 and 0.004, respectively). The MCD and HCD groups had lower hot carcass weight (P = 0.012) and dressing percentage (P = 0.022) than the LCD group. Compared with the HCD group, the LCD and MCD groups exhibited greater serum GSH (P = 0.029) and SOD (P = 0.032), but significantly lower levels of serum cortisol and cholesterol (P = 0.001 and 0.026, respectively). Regarding the amino acid profile of longissimus dorsi and leg muscles, the LCD group had significantly higher levels of muscle lysine and threonine than the HCD and MCD groups (P˂0.05). The current study indicates that the MCD (850 cm/rabbit) could maintain an acceptable growth performance, carcass traits, and welfare-related parameters. Furthermore, only the low cage density (1425 cm/rabbit) may preserve the levels of essential (lysine, isoleucine, and threonine) and nonessential (histidine, proline, and glysein) amino acids in the longissimus dorsi and leg muscles of growing rabbits.
本研究旨在阐明笼位密度对育肥兔生长效率、胴体产量和肌肉氨基酸谱的影响。总计 96 只断奶兔被分配到三个笼位密度组：低密度笼位（LCD）=1425 cm/只；中密度笼位（MCD）=850 cm/只；高密度笼位（HCD）=625 cm/只。与 HCD 相比，LCD 和 MCD 组的体增重和饲料转化率更好（P=0.003 和 0.004）。MCD 和 HCD 组的热胴体重（P=0.012）和屠宰率（P=0.022）均低于 LCD 组。与 HCD 组相比，LCD 和 MCD 组的血清 GSH（P=0.029）和 SOD（P=0.032）水平更高，但血清皮质醇和胆固醇水平显著降低（P=0.001 和 0.026）。就背最长肌和腿肌的氨基酸谱而言，LCD 组肌肉赖氨酸和苏氨酸水平显著高于 HCD 和 MCD 组（P˂0.05）。本研究表明，MCD（850 cm/只）可维持可接受的生长性能、胴体性状和福利相关参数。此外，只有低密度笼位（1425 cm/只）可维持生长兔背最长肌和腿肌中必需（赖氨酸、异亮氨酸和苏氨酸）和非必需（组氨酸、脯氨酸和甘氨酸）氨基酸的水平。
