The effects of dietary electrolyte balance on performance and eggshell quality of laying hens exposed to heat stress and thermo neutral condition in early laying period.

This study was conducted to evaluate the effects of different dietary electrolyte balance on performance and egg quality in early period of egg production under heat stress and thermo neutral condition. This experiment was done on hens that were in early of egg production period. Number of 56 Hy- line W-6 laying hens from 4 to 4 weeks of age were placed in two separated experimental room under heat stress and thermo neutral condition. Each experiment was carried out in a completely randomized design. Diets were formulated with inclusions of NaCl, NaHCO, KHCO and NH4Cl to give different dietary electrolyte balances (DEB) as 0, 0, 40 and 60 mEq/kg and were fed to laying hens for 0 weeks. Results of these experiments showed that performance of laying hens were not significantly affected by diets of various DEB in both heat stress and thermo neutral conditions. Eggshell quality were significantly affected by DEB (p<0.05). Under heat stress, eggshell weight and egg weight/surfaces and under thermo neutral condition, egg specific gravity, eggshell weight, eggshell thickness, eggshell ash and egg weight/surfaces were significantly affected by DEB and improved by increasing dietary electrolyte balance from 0 to 60 mEq/kg in many cases. In conclusion, increasing DEB to 60 mEq/kg in early period of egg production in heat stress and thermo neutral condition can improve eggshell quality.