Effect of delayed feeding post-hatch on expression of tight junction– and gut barrier–related genes in the small intestine of broiler chickens during neonatal development

Abstract

The gut not only plays a key role in digestion and absorption of nutrients but also forms a physical barrier and first line of defense between the host and the luminal environment. A functional gut barrier (mucus and epithelial cells with tight junctions [ TJ ]) is essential for optimal health and efficient production in poultry. In current broiler system, chicks are deprived of food and water up to 72 h due to uneven hatching, hatchery procedures, and transportation. Post-hatch feed delay results in lower BW, higher FCR and mortality, and delayed post-hatch gut development. Little is known about the effects of early neonatal development and delayed feeding immediately post-hatch on gut barrier function in chickens. Therefore, the aim of the present study was to characterize the expression pattern of gut barrier–related and TJ-related genes in the small intestine of broiler chickens during early development and delay in access to feed. Newly hatched chicks received feed and water immediately after hatch or were subjected to 48 h delayed access to feed to mimic commercial hatchery setting and operations. Birds were sampled (n = 6) at −48, 0, 4, 24, 48, 72, 96, 144, 192, 240, 288, and 336 h post-hatch. Jejunum and ileum were collected, cleaned of digesta, and snap-frozen in liquid nitrogen or fixed in paraformaldehyde. The relative mRNA levels of gut barrier- and TJ-related protein genes were measured by quantitative PCR and analyzed by 2-way ANOVA. In both tissues, changes ( P < 0.05) in gene expression pattern of gut barrier–related and TJ-related genes were detected due to delayed access to feed post-hatch and/or development. In general, expression of TJ-related genes was downregulated while mRNA levels of gut barrier-related genes were upregulated during development. Histological differences and changes in mucin staining due to age and treatment were observed. These results suggest that delayed access to feed post-hatch may affect TJ structure and/or function and therefore gut barrier function and overall health of the chicken small intestine.

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

“…Since the gut microbiota affects SI structure and function (Dobrowolski et al, 2019), the timing of microbial introduction by external feed may also play a critical role in shaping the SI epithelium. Although previous studies have demonstrated the effect of the timing of first feeding of chicks on growth, nutrient utilization, metabolic pathways, gut integrity, and immunity (Bigot et al, 2003;Bar Shira et al, 2005;de Jong et al, 2017;Hicks et al, 2019;Payne et al, 2019;Proszkowiec-weglarz et al, 2020), no study has shown the effects on crypt and villi epithelial cell sub-types, involved in cellular turnover and intestinal functionality. Our study is the first to show the effect of the timing of first feeding on the quantities and proportions of stem, progenitor, proliferating, and differentiated SI epithelial cells, through immunofluorescence and histochemical of specific cell sub-type markers.…”

“…Research shows that delayed first feeding in chicks disrupts SI development by limiting crypt depths and villus heights, altering epithelial proliferation patterns, dysregulating differentiation-associated genes, and disrupting mucin dynamics (Geyra et al, 2001(Geyra et al, , 2002Uni et al, 2003a, de Jong et al, 2017. Long-term systematic effects of delayed first feeding include impaired nutrient utilization, altered regulation of metabolic pathways, disrupted barrier functions, and impaired gut immunity, all of which jeopardize animal welfare, impair performance in increase mortality rates (Bigot et al, 2003;Bar Shira et al, 2005;de Jong et al, 2017;Hicks et al, 2019;Payne et al, 2019;Proszkowiec-weglarz et al, 2020). In this study, we aimed to evaluate how the timing of first feeding of chicks influences the quantities and distribution of specialized SI epithelial cell sub-types during the initial 10 days post-hatch.…”

Establishment of a novel probe-based RT-qPCR approach for detection and quantification of tight junctions reveals age-related changes in the gut barriers of broiler chickens

“…It is well known that age as well as environmental factors do influence the gut barrier in chicken [ 25 , 43 , 44 ]. In broiler chicken, the commencement of feed intake after hatch promotes intestinal development [ 24 , 45 ]. Especially in the small intestine, epithelial surface is constantly increasing due to villi enlargement and epithelial cell proliferation [ 46 ].The present study revealed a highly significant increase in the mRNA expression of the potentially pore-forming claudins 7 and 10 as well as of OCLN, MD2 and ZO1 in jejunum during that period.…”

“…Similar results were obtained for CLDN1, CLDN5, ZO1 and OCLN in a recent study of Proszkowiec-Weglarz et al . 2020, in which expressional changes of different intestinal developmental markers were observed in the small intestine of broiler chicks fed immediately after hatch or deprived from food for 48h [ 24 ].…”

“…In poultry, expression patterns of a large number of claudins has been analyzed during chick embryogenesis [ 20 – 22 ]. Developmental analysis of the chickens small intestine after hatching has been performed for CLDN1, CLDN3, CLDN4, CLDN5, CLDN16 as well as the TJ proteins OCLN and ZO-1 and ZO-2 [ 23 , 24 ]. Recently, it was revealed in many studies that the integrity of the chickens intestine has been disrupted by alteration in the mRNA expression of ZO-1, ZO-2, OCLN, CLDN1, CLDN3, CLDN4 and CLDN5 [ 25 – 28 ].…”