Effect of a gradual increase in the intensity of lighting on the physiological performance of broilers

Birds are exposed when the light is turned on by using the gradual increase of the light system. This study used 224 chicks (Ross 308) at one day old. Those chicks were randomly distributed into four treatments with four replicates for each treatment, i.e. (14 chicks/replicate). The treatments include the following: T1 the lighting program according to the guide for 308 ROSS company (Control Treatment), T2 the lighting program according to the guide with a gradual increase of lighting intensity every 20 minutes, T3 used the same method with an increase of lighting intensity every 40 minutes, T4 used lighting program with a gradual increase of lighting intensity every 60 minutes. The blood biochemical and hematological characteristics of 22 and 37 days of the age of chicks were studied. The results showed that females of T2 and T3 were significantly superior in blood sugar levels over the females of T1 and T4. Besides, it was observed that there was a significant decrease in the value of ALP enzyme in the blood of chicks males of all treatments compared with the control treatment. The H/L stress indicator was significantly decreased in T2, T3 and T4 compared with the control treatment. At the same time, there were no significant differences in other blood characteristics among all treatments. Finally, at the age of 37 days, it was noted that there was no significant difference among all blood characteristics at this age. It can be concluded that there were no significant effects of the gradual lighting intensity on the physiological performance of broilers. Still, at the period of 22 days, there was a reduction in stress levels, particularly H/L and very low-density lipoproteins. This experiment was conducted in the College of Agriculture, the University of Anbar's poultry fields for (37 days) the period from 18/10/2021 to 21/11/2021. the research was undertaken to reduce the effect of stress resulting from the sudden and high light intensity that birds are exposed to when the light is turned on by using the gradual increase of the light system. This study used 224 chicks (Ross 308) at one day old. Those chicks were randomly distributed into four treatments with four replicates for each treatment, i.e. (14 chicks/replicate). The treatments include the following: T1 the lighting program according to the guide for 308 ROSS company (Control Treatment), T2 the lighting program according to the guide with a gradual increase of lighting intensity every 20 minutes, T3 used the same method with an increase of lighting intensity every 40 minutes, T4 used lighting program with a gradual increase of lighting intensity every 60 minutes The blood biochemical of 22 and 37 days of the age of chicks were studied. The results showed that females of T2 and T3 were significantly superior in blood sugar levels over the females of T1 and T4. Besides, it was observed that there was a significant decrease in the value of ALP enzyme in the blood of chicks males of all treatments compared with the control treatment. The H/L ratio stress indicator was significantly decreased in T2, T3 and T4 compared with the control treatment.
 
In comparison, there were no significant differences in other blood characteristics among all treatments. Finally, at the age of 37 days, it was noted that there was no significant difference among all blood characteristics at this age. It can be concluded that there were no significant effects of the gradual lighting intensity on the physiological performance of broilers. Still, at 22 days, there was a reduction in stress levels, particularly H/L ratio and very low-density lipoproteins.
 
Keywords: Broiler ; ROSS 308 ; Light Intensity ; Lux; Blood characteristics