Rearing broiler chickens under monochromatic blue light improve performance and reduce fear and stress during pre-slaughter handling and transportation
The aim of this study was to evaluate the effect of monochromatic light on broiler performance, fear and stress response during pre-slaughter handling and transportation. Two thousand unsexed one-day old Cobb broiler chicks were used. At day 34, two hundreds broilers of similar live body weight were selected and divided into two equal groups (2 group x 5 replicates). Broilers were reared under white light (WL) from 0-34 day. From 35 to 49 day, the first group was reared under WL and the second group under blue light (BL). Final body weight (FBW), tonic immobility reactions (TI), respiratory rate (RR), heterophils to lymphocytes (H/L) ratio and interlukien-1β (IL-1β) were estimated at day 49 before and after transportation. After transportation, weight of internal organs (liver, spleen, heart and bursa of fabricius) as a percentage of FBW was calculated. Results showed that there was a significant (P < 0.05) increase in FBW and reduced weight loss due to transportation in broilers reared under BL. In broilers reared under BL: TI duration, RR, H/L ratio, IL-1β and weight of internal organs (except the heart) were significantly (P < 0.05) lower. The interaction effect of light and transportation on TI duration, RR, lymphocytes, H/L ratio and IL-1β were significant (P < 0.05). Therefore, it is suggested that BL may be a good tool for improving welfare and mitigating stress not only in pre-slaughter handling but also during transportation of broilers
