The effects of dietary electrolyte balance on performance and eggshell quality of laying hens exposed to high temperature and thermoneutral condition in late laying period

This study was conducted to evaluate the effects of different dietary electrolyte balance on performance and egg quality in late period of egg production under high temperature and thermoneutral conditions. This experiment was designed by using hens that were in late of egg production period. 256 Hy- line W-36 laying hens from 55 to 65 weeks of age placed in two separated experimental room under high temperature and thermoneutral conditions. Each experiment was carried out in a completely randomized design. Diets were formulated with inclusions of NaCl, NaHCO3, KHCO3 and NH4Cl to give different dietary electrolyte balance (DEB) as 0, 120, 240 and 360 mEq/kg and fed to laying hens for 10 weeks. Results of the experiments showed that performance of laying hens were not significantly affected by diets of various DEB in both high temperature and thermoneutral conditions. Eggshell quality was significantly affected by DEB (p<0.05). Under high temperature, egg specific gravity, eggshell weight, eggshell thickness and egg weight/surfaces and under thermoneutral condition, eggshell weight and eggshell thickness were significantly affected by DEB and improved by increasing dietary electrolyte balance from 120 to 360 mEq/kg in many cases. In conclusion, increasing DEB to 360 mEq/kg in late period of egg production in high temperature and thermoneutral conditions can improve eggshell quality.