Comparison of the broody behavior characteristics of different breeds of geese

A low laying performance in goose is one of the key factors preventing the industrial development, and the laying performance is related to broody behavior. However, the characteristics of broody behavior in geese remain unclear. In this study, the total 144 geese (300 day old), including Zhedong geese (Anser cygnoides), Sichuan geese (Anser cygnoides), and Carlos geese (Anser anser) were selected and assigned to 1 of 3 groups/breed (including 4♂+12♀). Laying and broody behaviors were recorded using the infrared video cameras from 2016 November 11 to 2017 June 15. The broody behavior was detected in 19.4% of Carlos geese, 33.3% of Sichuan geese, and 100% of Zhedong geese. Different goose breeds showed similar behavior characteristics. The low frequency of feeding, drinking, and low body weight were observed in the middle of broodiness. As the brooding progressed, the body temperature showed a downward trend and then recovered, whereas no difference was observed in Carlos goose. In addition, the plasma hormone concentration from different breeds and stages of broodiness were compared. The contents of FSH (follicle-stimulating hormone) and LH (luteinizing hormone) in geese were greater in the laying stage than that in the broody stage. Fewer FSH and LH were detected in Zhedong geese and Carlos geese, more in Sichuan geese. In broody goose, the PRL (prolactin) concentrations of the 3 goose breeds peaked in the middle of broodiness, and greater PRL was detected in Sichuan geese than those in Carlos geese and Zhedong geese. Finally, we compared egg production between the broody and non-broody geese in the observation period. The egg production of broody Carlos geese was 27, which was significantly higher than non-broody geese (14 eggs), while in Sichuan geese there was no significant difference between broody (24 eggs) and non-broody geese (26 eggs). Finally, the higher egg production was found with the more broody times in Zhedong geese. Taken together, although the different goose breeds showed similar broody behavior characteristics, the broody rate and hormone secretion were dissimilar, and the Zhedong geese exhibited strong broody feature.

Age-related changes of yolk precursor formation in the liver of laying hens

A rapid decline in egg production of laying hens begins after 480 d of age. Such a rapid decrease results predominantly from the ovarian aging, accompanied by endocrine changes, decreased yolk synthesis and accumulation, and the reduction in follicles selected into the preovulatory hierarchy. In this study, hens at 90, 150, 280, and 580 d old (D90, D150, D280, and D580, respectively) were compared for yolk precursor formation in the liver to elucidate effects of aging on laying performance. The results showed that liver lipid synthesis increased remarkably in hens from D90 to D150, but decreased sharply at D580 as indicated by the changes in triglyceride (TG) levels. This result was consistent with the age-related changes of the laying performance. The levels of liver antioxidants and total antioxidant capacity decreased significantly in D580 hens and the methane dicarboxylic aldehyde in D580 hens was much higher than that at other stages. The serum 17β-estradiol level increased from D90 to D280, but decreased at D580 (P<0.05). The expression of estrogen receptor α and β mRNAs in the liver displayed similar changes to the serum 17β-estradiol in D580 hens. Expressions of the genes related to yolk precursor formation and enzymes responsible for fat acid synthesis were all decreased in D580 hens. These results indicated that decreased yolk precursor formation in the liver of the aged hens resulted from concomitant decreases of serum 17β-estradiol level, transcription levels of estrogen receptors and critical genes involved in yolk precursor synthesis, and liver antioxidant status.