Acid-Base Balance in Laying Hens and Its Relationship with Diet Electrolytes at Cyclic Heat Stress

This experiment was conducted to determine the effects of different levels of anion-cation (67, 117, 167, 217, 267, 317, 367, 417 mEq/kg diet and drinking water) on eggshell quality as well as performance in laying hens at cyclic heat stresses (19-36?C). A total of one hundered and sixty white leghorn laying hens, strain Hy-line W-36 at 63 of weeks age were randomly allotted to 8 dietary treatments Five hens each in 4 replicates were considered in each cage. The experimental period lasted for 60 days. Variation in levels of anion-cation basal diet (Na+ + K+ - Cl-) were obtained by use of supplements sodium bicarbonate (NaHCO3) and calcium chloride (CaCl2). Egg weight, egg production, feed conversion ratio and egg output significantly differed (P<0.05) among treatments. Improvement in all the mentioned traits except in feed consumption were observed as a result of supplementing control diet (167mEq/kg) with 0.42% NaHCO3 (167mEq/kg). Levels of anion-cation did not affect shell thickness, shell percentage, eggshell strength and Haugh unit. All the measured factors were significantly differed (P<0.05) among duration times but did not have any effect on Haugh unit.