INRAE, Université de Tours, BOA, 37380 Nouzilly, France; Ondokuz Mayıs University, Agricultural Faculty, Department of Animal Science, 55139 Samsun, Turkey.
INRAE, Université de Tours, BOA, 37380 Nouzilly, France.
Poult Sci. 2022 Nov;101(11):102142. doi: 10.1016/j.psj.2022.102142. Epub 2022 Aug 27.
Two divergently selected broiler lines were created by selection for low (pHu-) or high (pHu+) Pectoralis major ultimate pH (pHu) in order to better understand the molecular mechanisms underlying meat quality traits in broilers and are also unique genetic resources reflecting low and high glycogen levels in chicken muscle. The present study aimed to reveal the correlated phenotypical changes of egg quality traits in broiler breeders from the 2 divergent lines at the 14th generation. Birds were reared on littered floor system until 18 wk of age and in individual cages up to 42 wk. Individual egg production was recorded daily from age at first egg to 42 wk. External (egg weight: EW and shape index: SI), internal (albumen height: AH, Haugh unit: HU, yolk index: YI, and yolk color: YC), and shell (shell percentage: ESP, thickness: EST and strength: ESS) characteristics of eggs in pHu- and pHu+ lines were measured in all eggs for 4 consecutive days at 26, 27, 28, 30, 31, 32, 41, and 42 wk of age. The pHu- line had significantly higher egg percentage than pHu+ (55.9 and 49.1%, respectively). The EW in pHu- line (57.2 g) was significantly lower than in pHu+ (59.0 g) and increased with age in both lines. The mean ESP, EST and ESS were lower in the pHu+ eggs compared to the pHu- line. ESP and EST decreased mainly from 26 to 27 wk of age and they had a stable trend with advancing age in the remaining weeks. AH and YI were lower in pHu- line eggs than in pHu+. YC was more intense and HU higher in pHu+ eggs than pHu- in pre-peak and peak laying period. In conclusion, these results showed that a divergent selection for muscle energy metabolism has led to correlated responses on internal and external egg quality traits and suggest that the production of good-quality eggs may be impaired in broiler breeders with low energy reserves.
为了更好地了解肉鸡肉质性状的分子机制，我们选择了两条具有不同方向的肉鸡品系，一条是选择低（pHu-）胸肌最终 pH 值（pHu），另一条是选择高（pHu+）胸肌最终 pH 值。这两条品系也是反映鸡肌肉中低和高糖原水平的独特遗传资源。本研究旨在揭示第 14 代两个不同方向的肉鸡选育系中种鸡产蛋质量性状的相关表型变化。鸡在 18 周龄前在垫料地板系统中饲养，18 周龄后在单个笼子中饲养，直到 42 周龄。从第 1 个产蛋日到 42 周龄，每天记录个体产蛋量。在 26、27、28、30、31、32、41 和 42 周龄时，在 pHu-和 pHu+品系的所有鸡蛋中连续 4 天测量鸡蛋的外部（蛋重：EW 和形状指数：SI）、内部（蛋白高度：AH、哈夫单位：HU、蛋黄指数：YI 和蛋黄颜色：YC）和蛋壳（蛋壳百分比：ESP、蛋壳厚度：EST 和蛋壳强度：ESS）特征。pHu-系的蛋比例显著高于 pHu+系（分别为 55.9%和 49.1%）。pHu-系的 EW（57.2 g）显著低于 pHu+系（59.0 g），并且在两条系中随年龄增长而增加。与 pHu-系相比，pHu+系的平均 ESP、EST 和 ESS 较低。ESP 和 EST 主要从 26 到 27 周龄下降，并且在剩余周龄中随着年龄的增长呈现稳定趋势。pHu-系的 AH 和 YI 低于 pHu+系。在预产蛋高峰期和高峰期，pHu+系的 YC 颜色更深，HU 更高。总之，这些结果表明，对肌肉能量代谢的分歧选择导致了内部和外部鸡蛋质量性状的相关反应，并表明能量储备低的肉鸡种鸡可能会生产出质量较差的鸡蛋。
