EFFECT OF INTERMITTENT LIGHTING ON THE CARCASS CHARACTERISTICS, INTERNAL ORGANS, RELATIVE WEIGHT AND PH VALUE OF THE DIGESTIVE SYSTEM, AND SOME OF THE IMMUNOLOGICAL TRAITS OF BROILER CHICKEN

Abstract

This study was conducted at the field of poultry farm of the Department of Animal Production / College of Agriculture Engineering Sciences / University of Baghdad / Abu Ghraib during the period from 22/9-10/11/2019 (for a period of 49 days). This study aims to demonstrate the effect of different systems of lighting on production performance, leg abnormalities, total mortality rate and some microbial traits in broiler chickens. 300 unsexed Ross308 chicks were used in the study at one day age with an average initial weight of 37.5 g. They were randomly distributed to five experimental treatments with three replicates for each treatment. Chicks were fed on starter diet for the first three weeks of age, and finisher diets for the fourth, fifth, sixth and seventh weeks of bird age. All birds switched to continuous lighting (24 hours light) during the first week of age. On the eighth day, the experiment was divided into five treatment ,The first program was Tc (control) 24 hours of light, the second T1:18 hours of light: 6 hours of darkness, and the third T2: 19 hours of light: 2 hours of darkness: 1 hour of light: 2 hours of darkness and the fourth T3:17 hours of light: 3 hours of darkness :1 hour of light: 3 hours of darkness, 5 hours of darkness, T4: 15 hours of light: 4 hours of darkness: 1 hour of light: 4 hours of darkness. (Up to the age of 6 weeks) and at the seventh week, all birds were exposed to continuous lighting for 24 hours of light. The results indicated that there were no significant differences in dressing yield with out and with edible organs at 6,7 weeks. While significant differences (P <0.05) were observed in the relative weight of the thighs and wings parts in the treatment T3 compared with the control Tc treatment at the seventh week of age and a high significant superiority (P <0.01) for the treatment T3 in the relative weight of neck cutter for the same age, Whereas, the control Tc treatment was significantly superior (P <0.05) in the relative weight of the liver compared to the T1 treatment at the sixth week of age. Treatment T2 (P<0.01 and P <0.05) was significantly compared with all trial treatments in pH value in crop, duodenum and ileum at 7 weeks of age. A significant increase (P <0.05) was observed in the T2 treatment compared to the control treatment in the relative weight of thymus gland at the seventh week of age, and highly significant (P <0.01) in the T3 treatment compared to the control treatment in the antibodies directed against Newcastle disease. Conclusion: It is concluded from this study that intermittent lighting programs Improved immune system function and reinforcement Production of antibodies against Newcastle disease and improved pH value of the digestive system. Keyword: intermittent light, carcass characteristics, pH value, digestive system, immune system