effect of lemon juice on the egg shell quality of layers subjected to heat stress

heat stress is an effective factor on immune responses, body weight, egg production and egg quality of chickens. the major effect of heat stress is due to decreased food intake and alteration in acid-base balance. during the recent years, efforts to improve laying performance at high temperatures have been relatively successful. supplementation of the diet or drinking water with special nutrient has been proposed as a means to reduce the effects of heat on the layer hens. there is scantly information about the effects of natural compounds on the heat-stressed hens. in this regard, the aim of the present study was to determine the effect of lemon juice on egg shell quality in layers subjected to hot climate. 50-week-old commercial layer chickens were divided into 2 equal treatment groups of 2400 birds each. each treatment has three replicates. the experimental groups were fed as follows: in the control and test groups (groups a and b), birds were fed a standard diet. in the test group (group b), 5 ml/l of lemon juice was added to the drinking water for 30 days. at the end of each week, eggs with broken and fragile shellwere recorded. our results showed that the addition of lemon juice in drinking water was significantly reduced eggs with broken and fragile shells during heat stress (p