Comparative study on the uropygial glands of three goose breeds: a histomorphological and transcriptomic perspective

The uropygial gland is a gland peculiar to birds, and it is widely recognized that its secretion confers water-repellent properties on the feather coat and maintains the suppleness of the feathers. The aim of this study was to reveal differences in the developmental patterns and the regulatory mechanisms of the uropygial glands among different goose breeds (Sichuan White goose, SW; Landes goose, LD; and Gang goose, GE) through comparative analysis of their uropygial gland histomorphological parameters and transcriptomic data during the period from week 0 to week 30 post-hatching. Morphologically, our results showed that the uropygial gland weight of LD was significantly lower than that of SW (P < 0.01) and GE (P < 0.05) at week 10 but was significantly higher than that of SW and GE at week 30 (P < 0.01). Histologically, the tubular area of zone I, the interlobular septum, luminal area, and epithelial thickness of zone II, and the luminal area of zone III increased with age in the uropygial glands among almost all three goose breeds. Moreover, these histological parameters differed most significantly at week 30, when the luminal area and epithelial thickness of zone II were significantly greater in SW than in LD (P < 0.05) but the luminal area of zone III was significantly greater in LD than in SW (P < 0.05). Comparative analysis of the uropygial gland transcriptomes of LD and SW at week 10 and 30 further identified several key genes, signaling pathways, and interactions networks that are involved in regulating the breed- and age-related goose uropygial gland development. The uropygial glands of LD might have a stronger capacity of lipid synthesis and secretion when approaching the age of sexual maturity. GPAT3, LPIN2, EP300, and MGMT involves breed-related uropygial gland development. LCAT, PLPP3, TIMP2, and MFAP5A involves age-related uropygial gland development. Besides, the glycerophospholipid metabolism pathway may be the main regulatory pathway for lipid metabolism in the uropygial gland of LD.