Proliferation dynamics of enterocytes: Implications for intestinal barrier function, performance, health, and welfare in broiler chickens.

Intestinal health is a central determinant of growth, performance, health and welfare in modern broiler chickens. Enterocytes, the primary functional cells of the intestinal epithelium, play a pivotal role in nutrient digestion, absorption, barrier integrity and host defense. Continuous proliferation, differentiation, migration and exfoliation of enterocytes along the crypt-villus axis maintain epithelial homeostasis and intestinal efficiency. Disruption of these tightly regulated processes can compromise barrier function, reduce nutrient utilization, impair growth performance and increase susceptibility to enteric disorders. This review critically examines the current understanding of enterocyte proliferation dynamics in broilers and their implications for intestinal barrier function, efficiency, performance, health and welfare. Key cellular and molecular mechanisms regulating enterocyte proliferation are discussed, including major signaling pathways, nutrient sensing systems and stem cell interactions. Nutritional regulation, microbiota-derived modulation and early-life programming of the intestinal epithelium are highlighted as major factors influencing proliferation. The relationships between enterocyte turnover, barrier integrity, digestive capacity and feed efficiency are explored with relevance to production systems. Furthermore, enterocyte proliferation responses to physiological stress, immune challenges and enteric diseases are evaluated, emphasizing their role in recovery and resilience. Methodological approaches, including histomorphometry, immunohistochemical markers and molecular techniques, are discussed with consideration of their limitations and standardization challenges. Critical knowledge gaps are identified, and future research directions are proposed to support precision nutrition and management strategies aimed at optimizing intestinal barrier function, growth performance, metabolic efficiency, health and welfare of the broiler chickens.