Silky Fowl (Gallus gallus domesticus) Dietary Supplementation with Dried Red Pepper (Capsicum annuum): Effects on Egg Quality, Blood Biochemical Parameters, and Egg Storage Stability

Egg yolk coloration influences consumer perceptions of table eggs. Red pepper (Capsicum annuum) is a known dietary source of carotenoids, which enhances yolk pigmentation, but its effects in silky fowl (SF) remain unexplored. We examined how dried red pepper flakes influence blood biochemical parameters and egg quality in SF hens. Sixty hens were divided into three groups: basal ration (control), low supplementation (3.5 mg/100 g), and high supplementation (7.0 mg/100 g). During a 35-day feeding period, eggs collected in the final week were maintained at 4 or 25 °C for quality evaluations. Haugh units and the yolk index were decreased significantly in eggs maintained at 25 °C compared with those in the day 0 and 4 °C samples, whereas the yolk carotenoid content decreased with the storage duration, particularly in the high-supplementation group. CIELAB parameters (L*, a*, a/b), except for b*, were more strongly associated with the ZEN-NOH Yolk Color Chart Score than the DSM Yolk Color Fan Score, particularly in the high-supplementation group. In addition, serum high-density lipoprotein cholesterol was increased, and triglyceride levels were decreased in the high-supplementation group. In conclusion, dietary red pepper flakes enhance yolk pigmentation and lipid metabolism in SF hens. Moreover, ZEN-NOH YCCS provides a reliable indicator of the yolk color after dietary carotenoid supplementation.