Effects of choline on reproductive performance, egg quality, and ovarian morphological development in laying geese

Abstract

We aimed to explore appropriate dietary choline concentrations in laying geese based on the evaluation of it’s effect on reproductive performance, egg quality, ovarian morphology, ovarian development, serum hormone concentrations, and gene expression of reproductive hormone-related receptors in laying geese. 94-week-old Yangzhou geese (n = 648) were randomly allocated into six groups, each with six replicates of 18 birds, corresponding to a choline supplementation of 0 (control), 200 (C200), 400 (C400), 600 (C600), 800 (C800), and 1000 (C1000) mg/kg, with choline concentrations at 328, 510, 755, 955, 1149, and 1314 mg/kg in the feed for 56 days, respectively. The average daily feed intake (ADFI) and the feed conversion ratio (FCR) were decreased, whereas the egg production rates (EPR), total number of eggs, total weight of eggs, albumen height, yolk color, geese’s serum testosterone (T), estradiol (E₂) and progesterone (P₄) were increased in C400 and C600 compared to the control (P < 0.05). The number of small white follicles (SWF) was more in C600 compared to the control and C400 (P < 0.05). The total weight of graded follicles (GF) was increased in C400 compared to the other groups (P < 0.05). The estrogen receptor 1 (ESR1) mRNA expression levels were higher in C600, C800, and C1000 than in control (P < 0.05). However, the mRNA expression levels of estrogen receptor 2 (ESR2) were lower in C200 to C1000 than in control (P < 0.05). The ADFI, FCR, EPR, total number of eggs, total weight of eggs, total weight of GF, and geese serum T, E₂, P₄ showed significant quadratic fitting within the choline concentration range of 784–913 mg/kg. A range of 784–913 mg/kg choline is recommended to improve the reproductive performance of laying geese via promoting the synthesis and secretion of sex hormones.