The Evaluation of UPro as a New Nutrient on High-Quality Egg Production From the Perspective of Egg Properties, Intestinal Histomorphology, and Oviduct Function of Laying Hens

This study was to investigate the effects of UPro as a new nutritive fortifier on high-quality egg production from the perspective of egg properties, intestinal histomorphology, and oviduct function of laying hens. Four hundred thirty-two Hy-Line Brown laying hens aged 56 weeks were allocated to four groups. Layers were given a basal diet or supplemented with different levels of small peptides (0.2, 0.4, and 0.8%) to replace soybean meal. After 1-week adaptation period, the feeding trial was conducted for 12 weeks. The results showed that UPro addition significantly decreased (P < 0.05) the hardness, stickiness, and chewiness of albumen of layers on weeks 12. A linear elevation (P < 0.05) in the albumen height, Haugh unit (HU), and crude protein content of albumen of layers were noted on week 12 along with dietary UPro addition increasing, and the villus height (VH) and villus height-to-crypt depth radio (VCR) of jejunum also linearly increasing (P < 0.05). In addition, there were linear elevations (P < 0.05) in the relative mRNA expression of Sec23 homolog A (Sec23A) and protein-O-mannosyltransferase1 (POMT1) in layers as dietary UPro addition increased. In conclusion, dietary UPro addition could improve intestinal health, increase the absorption of nutrients, and improve egg quality of laying hens. The possible mechanism underlying UPro improving the quality and processing characteristics of albumen is up-regulating Sec23A and POMT1 expression of magnum. These findings will promote the application of UPro as a new nutritional additive in the production of high-quality eggs.