Effects of granular feed on reproductive metabolism of breeding pigeons, intestinal development and microbiota of squab pigeons–A double-edged sword

Pigeons like to eat raw grains, but meat pigeon enterprises often use compound feeds instead of raw grains to feed breeding pigeons to increase economic efficiency, which may change the pigeon's dietary behavior, and consequently lead to health and welfare problems. The purpose of this study was to investigate the effect of granular feeds on the health of high-yielding breeding pigeons and squabs in lactation. The results showed that, compared with raw grain group, the provision of granular feed resulted in lower total feed intake without affecting the weight of lactating breeding pigeons. Meanwhile, reproductive metabolism was improved and no oxidative stress was observed, which indicated that granular feeds had a positive effect on breeding pigeon's health. However, granular feed adversely affected jejunum development in squabs, compare wtih raw grain group, the growth rate of squab was reduced. Sequencing of the 16 s rRNA gene revealed that granular feed induced intestinal microbiota dysbiosis in the squabs. The use of granular feed reduced the relative abundance of gut microorganisms in functional categories related to lipid and energy metabolism, resulting in a decrease in the relative abundance of beneficial bacteria such as Bifidobacterium, Ligilactobacillus, Atopobium, and an increase in that of inflammation-related Limosilactobacillus, which likely inhibited squab intestinal development and growth. Although the use of granular feed can improve breeder metabolism, it affect the composition of the microbial community and gut development of squabs. Therefore, the use of granular feed in production should be more careful to avoid causing growth obstruction of squab.