Wu Hanxiao, Li Hu, Hou Yuanyuan, Huang Lin, Hu Jianing, Lu Yangqing, Liu Xingting
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Animal Science and Technology, Guangxi University, Nanning, China.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Animal Science and Technology, Guangxi University, Nanning, China.
Theriogenology. 2022 May;184:13-25. doi: 10.1016/j.theriogenology.2022.02.020. Epub 2022 Feb 24.
Egg yolk formation and deposition are quite vital for oocyte maturation and egg production in hens. There are great differences in egg production and number of preovulatory follicles among individuals in Guangxi Ma chickens at the same or various ages, however, the causes of this phenomenon remain unclear. This study aimed to elucidate the differences in yolk precursors formation among Guangxi Ma hens at the same or various ages with dissimilar egg laying rate via comparing the synthesis and transportation of yolk precursors, serum estradiol (E) levels, as well as the antioxidant capacity of the liver and serum from hens of 32-week-old (32W), 50-week-old with higher laying rate (50WH), 50-week-old with lower laying rate (50WL), 72-week-old with higher laying rate (72WH), and 72-week-old with lower laying rate (72WL). The results showed that the contents of triglyceride (TG), total cholesterol (T-CHO), high density lipoprotein cholesterol (HDL-C) and very low density lipoprotein cholesterol (VLDL-C) in the liver, serum and ovarian stroma, serum E levels, expression levels of proteins and genes related to yolk precursors formation, and the antioxidant capacity of liver and serum decreased significantly during aging process. TG, HDL-C and VLDL-C contents in serum and ovarian stroma, as well as HDL-C and VLDL-C levels in liver tissues of hens in 50WL and 72WL were significantly lower compared to hens in 50WH and 72WH, respectively. Meanwhile, expression levels of estrogen receptor ɑ and transcription levels of genes related to lipid transportation in liver tissues, and the antioxidant capacity of livers were remarkably lower in hens in 50WL and 72WL than those in 50WH and 72WH, respectively. However, no significant difference was detected in liver TG levels, serum E levels, genes related to fatty acids synthesis and serum antioxidant capacity between hens in 50WL and 50WH. In conclusion, the age-related decline of egg production in Guangxi Ma chicken maybe related to the age-related decreases in the synthesis and transportation of liver yolk precursor as well as the antioxidant capacity of liver and hens. And the non-age related decline of egg production may mainly attribute to the decreases in yolk precursors transportation ability and hepatic antioxidant capacity.
蛋黄的形成和沉积对于母鸡的卵母细胞成熟和产蛋至关重要。广西麻鸡在相同或不同年龄时，个体间的产蛋量和排卵前卵泡数量存在很大差异，然而，这种现象的原因尚不清楚。本研究旨在通过比较32周龄（32W）、产蛋率较高的50周龄（50WH）、产蛋率较低的50周龄（50WL）、产蛋率较高的72周龄（72WH）和产蛋率较低的72周龄（72WL）母鸡的卵黄前体合成与转运、血清雌二醇（E）水平以及肝脏和血清的抗氧化能力，阐明相同或不同年龄、产蛋率不同的广西麻母鸡在卵黄前体形成方面的差异。结果表明，在衰老过程中，肝脏、血清和卵巢基质中的甘油三酯（TG）、总胆固醇（T-CHO）、高密度脂蛋白胆固醇（HDL-C）和极低密度脂蛋白胆固醇（VLDL-C）含量、血清E水平、与卵黄前体形成相关的蛋白质和基因表达水平以及肝脏和血清的抗氧化能力均显著下降。与50WH和72WH母鸡相比，50WL和72WL母鸡血清和卵巢基质中的TG、HDL-C和VLDL-C含量以及肝脏组织中的HDL-C和VLDL-C水平分别显著降低。同时，50WL和72WL母鸡肝脏组织中雌激素受体ɑ的表达水平和与脂质转运相关基因的转录水平以及肝脏的抗氧化能力分别显著低于50WH和72WH母鸡。然而，50WL和50WH母鸡之间的肝脏TG水平、血清E水平、与脂肪酸合成相关的基因及血清抗氧化能力未检测到显著差异。总之，广西麻鸡产蛋量与年龄相关的下降可能与肝脏卵黄前体合成和转运以及肝脏和母鸡抗氧化能力随年龄增长而降低有关。而产蛋量与年龄无关的下降可能主要归因于卵黄前体转运能力和肝脏抗氧化能力的降低。
