Preventing of heat stress with different feeding methods in laying hens

63 6.SUMMARY The objective of this study was to determine the effects of different density diets and different feeding methods on feed and water consumption, body weight change, egg production and egg quality, blood acid-base balance, hematocrit value and nutrient digestibility of laying hens at heat stress. 16 week old hens (Ross Brown) were divided into 6 group of 30 hens each and study was conducted in 3x2 factorial experiment design. Experimental diets were a normal nutrient density, Diet N ( %15 HP, 2700 kcal/kg ME ) or high nutrient density, Diet Y ( % 18 HP, 3025 kcal/kg ME).The diets were given to animals with three methods during heat stress. According to this feeding methods were as follows: Both of the diets were given to hens through traditional ways Control Group: On the hottest hours of days, feed withdrawal was conducted and the darkening was excluded, Withdrawal Group: and house was darkened by black curtains between 1400-18 00 p.m. and feed withdrawal was not done, Darkening Group. At the end of study, average daily feed intake were 112.48, 100.50, 118.01, 105.74, 123.82, and 1 1 1.82 in control N, control Y, feed withdrawal N, feed withdrawal Y, darkening N, darkening Y groups, respectively. Diets and feeding methods had significant effects on feed intake (P<0.01). The highest water intake was in control group, this group followed by feed withdrawal and darkening group (p<0.0l). During the treatment, the highest body weight was determined in darkening group, this group followed by feed withdrawal and control gr{>up. The differences among feeding methods were significant in groups (PO.01). The average egg production in groups were 57. 1 1, 59.43, 64.43, 65.62, 69.79, and 73.68 and egg weights were 53.05, 53.40, 54.35, 54.64, 55.19 and 55.30, respectively. The highest egg shell thickness, egg weight, egg specific gravity was found darkening group, this group followed by was withdrawal and control groups. Feeding methods had significant effects on egg shell thickness, egg weight, egg specific gravity, egg formation, egg yolk formation, haughunit(P<0.01). During the treatment, feeding methods had influence on blood pH, pCC>2, pHCCb concentration and hematocrit value (P<0.01).64 Digestibility of nutrient value were higher in darkening group, this group followed by withdrawal and control group with the particular consideration of feeding methods. The differences were significant statistically (PO.01). This results of investigation indicate that the darkening house between H00-^00 p.m. at heat stress had an increase in performance, egg production and quality and nutrient digestibility of laying hens.