摘要Nutritional stimulation of the developing small intestine of chick embryos can be conducted by in-ovo feeding(IOF).We hypothesized that IOF of glutamine and leucine can enhance small intestinal devel-opment by promoting proliferation and differentiation of multipotent small intestinal epithelial cells.Broiler embryos(n=128)were subject to IOF of glutamine(IOF-Gln),leucine(IOF-Leu),NaCl(IOF-NaCl)or no injection(control)at embryonic d 17(E 17).Multipotent,progenitor and differentiated cells were located and quantified in the small intestinal epithelium between E 17 and d 7 after hatch(D 7)in all treatment groups by immunofluorescence of SRY-box transcription factor 9(Sox9)and proliferating cell nuclear antigen(PCNA),in-situ hybridization of leucine-rich repeat containing G-protein coupled receptor 5(Lgr5)and peptide transporter 1(PepT1)and histochemical goblet cell staining.The effects of IOF treatments at E 19(48 h post-IOF),in comparison to control embryos,were as follows:total cell counts increased by 40％,33％and 19％,and multipotent cell counts increased by 52％,50％and 38％,in IOF-Gln,IOF-Leu and IOF-NaCl embryos,respectively.Only IOF-Gln embryos exhibited a significance,36％in-crease in progenitor cell counts.All IOF treatments shifted Lgr5+stem cell localizations to villus bottoms.The differentiated,PepT1+region of the villi was 1.9 and 1.3-fold longer in IOF-Gln and IOF-Leu embryos,respectively,while goblet cell densities decreased by 20％in IOF-Gln embryos.Post-hatch,crypt and villi epithelial cell counts were significantly higher IOF-Gln chicks,compared to control chicks(P＜0.05).We conclude IOF of glutamine stimulates small intestinal maturation and functionality during the peri-hatch period by promoting multipotent cell proliferation and differentiation,resulting in enhanced compart-mentalization of multipotent and differentiated cell niches and expansions of the absorptive surface area.