Effects of formic acid administration in the drinking water on production performance, egg quality and immune system in layers during hot season

The objective of this study was to determine the effects of formic acid on egg production, egg weight, feed conversion ratio, egg quality and immunity in commercial layer reared during the hot season. In this study, 360 Hy-Line W-98 commercial White Leghorn, 68-week old hens were randomly assigned into four groups. The first group (control) continued receiving normal drinking water and other three groups consumed drinking water containing formic acid at levels of 0.5, 1.0 and 1.5 mL L-1. The results showed that the laying hens that consumed drinking water with formic acid had greater egg production, egg weight and egg mass than the control. Similarly, feed conversion improved with the administration of formic acid in water. Haugh units, egg shell thickness and egg grading from hens consuming acidified water containing 1.0 or 1.5 mL L-1 were significantly greater than those from the control group. Formic acid had no effect on yolk colour. In addition, the geometric means HI titres against Newcastle disease of birds consuming water containing formic acid were higher on all sampling days than those consuming water without acid. This study showed that formic acid at levels of 1.0 or 1.5 mL L-1 positively influences egg production, egg weight, shell quality, egg grading and enhances the immunity in older commercial layers during the hot season.