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.Copyright © 2022 Elsevier Inc. All rights reserved.
About The Expert