It’s All About Timing: Early Feeding Promotes Intestinal Maturation by Shifting the Ratios of Specialized Epithelial Cells in Chicks

Abstract

The small intestine (SI) of chicks (Gallus gallus) matures rapidly during the initial post-hatch period and acquires digestive, absorptive, and secretive capabilities. The effects of the timing of first feeding on the quantities and distribution of specialized epithelial cells, which generate and maintain SI morphology and functionality, have not yet been examined. In this study, we identified specialized SI epithelial cell sub-types, including stem, progenitor, proliferating, and differentiated cells within crypts and villi of chicks during the first 10 days post-hatch, by in situ hybridization (ISH), immunofluorescence (IF), and histochemical staining. We then examined their quantities and ratios between day of hatch and d10 in chicks that were fed upon hatch [early feeding (EF)], compared to chicks that were fed 24 h post-hatch [delayed feeding (DF)]. Results showed that EF increased total cell quantities in the crypts and villi at days 1, 3, 7, and 10, compared to DF (p < 0.0001). At d3, EF, in comparison to DF, decreased crypt stem cell proportions (p < 0.0001), increased crypt proliferating (p < 0.01) and differentiated (p < 0.05) cell proportions, and increased villus enterocyte proportions (p < 0.01). By d10, EF increased both the quantities and proportions of villus enterocytes and goblet cells, compared to DF. We conclude that feeding upon hatch, compared to 24 h-delayed feeding, enhanced SI maturation and functionality by increasing the quantities and proportions of proliferating and differentiated cells, thus expanding the digestive, absorptive, and secretive cell populations throughout the initial post-hatch period.

Nutritional Stimulation by In-ovo Feeding Modulates Cellular Proliferation and Differentiation in the Small Intestinal Epithelium of Chicks

“…Nevertheless, since the post-Hatch SI epithelium in all groups portrayed similar stem, proliferating and differentiated cell localizations, which were in accordance with previous studies (6,11,36,39,50), the expanded post-Hatch SI epithelium in IOF-Gln chicks was made up of a larger PepT1-expressing surface area, indicating a greater absorptive capacity, compared to Control chicks.…”

“…In contrast, IOF of leucine and NaCl only increased villi cell counts at D1. Increased villus cell counts at D1 were previously found to be a result of primary feeding (11), therefore the combination of IOF and primary exogenous feeding may have elicited a prominent effect within the rst 24h post-hatch. Furthermore, general decreases in the percentages of crypt MP cells and villus proliferating cells were observed during the rst week post-hatch, in accordance with previous studies (5,11), and were inconsistently affected by IOF, indicating that the effects of IOF on cellular proliferation and differentiation is most prominent pre-hatch.…”

“…In chicken embryos (Gallus gallus), villi formation occurs at the 15th day of embryonic development (E15), and crypts develop at E21 (day of hatch, DOH) (5)(6)(7). Post-hatch, initial feeding stimulates the completion of SI maturation through expansions of the crypt and villus epithelium, mediation of cellular proliferation and differentiation and activation of nutrient transporters, digestive enzymes and mucin secretion (5,6,(8)(9)(10)(11).…”

Intra-Amniotic Administration of l-Glutamine Promotes Intestinal Maturation And Enteroendocrine Stimulation In Chick Embryos

“…Taken together, intra-amniotic administration of Gln enhanced intestinal developmental dynamics by promoting enterocyte growth, nutrient transporter expression and tight junction formation, thus improving post-hatch nutrient absorption and intestinal integrity. These effects were restricted to the rst week post-hatch, after which the small intestinal epithelium reaches maturity [4,10].…”

“…During this period, the small intestinal mucosa gains functionality through cellular growth, proliferation and differentiation of enterocytes [4,5], as well as expansion of enterocyte brush border surface areas through microvilli assembly [6,7]. Initial post-hatch feeding is a key stimulatory factor for these processes [8,9,10,11], yet nutritional stimulation of the small intestine begins in-ovo, from embryonic day 17 (E17), when the embryo starts ingesting its amniotic uid [1,2,12,13]. A method developed for enriching the amniotic uid with nutrients has been widely used for examining the effects of pre-hatch nutritional stimulation on development of the small intestine [13].…”