Influence of Extract Mixture from Scutellaria baicalensis and Lonicera japonica on Egg Production, Nutrient Digestibility, Blood Profiles and Egg Quality in Laying Hens Reared in Hot Humid Season

摘要

Heat stress is a demanding issue that results in substantial economic losses for the hens' husbandry industry. A 8-wk feeding trial was conducted to evaluate the dietary herbal extract mixture (Scutellaria baicalensis and Lonicera japonica, HEM) supplementation as a means of ameliorative strategy against the adverse effects of seasonal heat stress on performance of laying hens. In total, 288 ISA Brown 25-wk-old layers were divided into three treatments: CON, basal diet; T1, basal diet with 0.025% HEM; T2, basal diet with 0.05% HEM. There were no differences (P > 0.05) in egg production and nutrient digestibility among treatments throughout the experimental period. The HEM supplementation increased (P < 0.05) eggshell thickness and eggshell strength during 4th and 8th wk, respectively. Compared with CON, yolk height was increased (P < 0.01) in response to HEM treatments during the 8th wk. The Haugh unit was improved (P < 0.01) by the addition of HEM in 4th wk and 8th wk. Additionally, there was a significant reduction (P < 0.05) in serum cortisol concentration upon dietary supplementation of 0.05% HEM. In conclusion, precised HEM supplementation could improve eggshell strength and shelf life in laying hens when reared under hot climatic conditions.