MOLECULAR CHARACTERIZATION AND GASTROINTESTINAL TRACT ECOLOGY OF COMMENSAL HUMAN FOOD-BORNE BACTERIAL PATHOGENS IN THE CHICKEN
Location: Poultry Microbiological Safety Research
Title: Photoperiod effects on broiler behavior
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2008
Publication Date: July 20, 2008
Citation: Brown, A., Webster, A.B., Fairchild, B.D., Buhr, R.J. 2008. Photoperiod effects on broiler behavior. Poultry Science Association Meeting Abstract. 87:(Supp. 1) 191, P61.
This study evaluated the effects of 3 photoperiod regimes on behavior of commercial broilers. The photoperiods were 23h for all treatments from 1-6d. Treatments 1 and 2, 20L:4D and 18L:6D respectively, were applied from 7-36d and increased to 23L:1D at 37d. Treatment 3 was a step-down/step-up program where photoperiod was changed to 18h at 7d and decreased by 3h at 10 and 13d to achieve 12L:12D. Photoperiod was then increased to 18h by 1h increments between 22-27d followed by another increase to 23h by 1h increments between 37-41d. Light intensity was maintained at 20 lux using incandescent bulbs. Two trials were conducted with each light treatment applied to 2 rooms per trial and 6 pens per room. Video recordings were taken of 2 pens in each room at 9, 15, 22, 29, and 43d to observe: standing, walking, feeding, drinking, wing flapping, preening, non-nutritive pecking, and inactivity. In addition, heterophil to lymphocyte ratios were recorded at 38d in both trials and gait scores were observed during week 6 of trial 2. Broiler management protocols followed the breeder company recommended guidelines with water and a standard series of broiler diets provided ad libitum and stocking density = 0.7 sqft/bird.
At 22d, birds in treatments 2 and 3 were significantly more inactive over the 24h period than birds in treatment 1. No other significant differences were evident for behaviors averaged over the 24h period. During the dark period, however, broilers in treatment 3 performed significantly more standing and walking at 22d. Feeding was significantly higher at 28d in treatments 2 and 3 during the light period compared to treatment 1. There were no significant differences in heterophil to lymphocyte ratios, suggesting that the birds were not stressed from the light treatments, or gait scores among the treatments. Therefore, long photoperiods allow broilers to apportion their time to behaviors other than feeding and short photoperiods may cause birds to be more active during dark periods due to lack of time to be active during light hours.