Comparative Intestinal Histological Features Observed in 1940 Leghorn vs. 2016 Leghorn-Based Commercial Laying Hens Fed Representative Diets

Nutrient absorption is essential for all stages of life and production in Leghorn hens. The selection for production traits, specifically linked to promoting digestive utilization of feed, has resulted in improved feed efficiency and ultimately increased egg production. Digestion of ingested feed and nutrient absorption takes place within the small intestine by the crypts and villi of the absorptive epithelium, specifically in the crypts and microvilli. Understanding the absorptive epithelium and its structural changes, related to genetic selection and improved feed efficiency, is important for continued efforts to improve egg production. The objective of this study was to determine and compare the histological changes in the duodenum, jejunum, and ileum of the 1940 Leghorn vs. the 2016 Leghornbased commercial laying hens fed diets representative of those fed by the industry during the respective years of production.