Pekin duck productivity, physiological stress, immune response and behavior under 20L:4D and 16L:8D photoperiods

As duck production becomes more prevalent on a global scale, modern duck housing systems must utilize artificial lighting photoperiods to maximize production and welfare; however, limited research has examined the manipulation of photoperiods on Pekin ducks. The objective of this study was therefore to determine the effects of two photoperiods-20 h of light (L): 4 h of darkness (D) and 16 L:8D - on the growth, stress, and fear responses of 384 Pekin ducks during the grow-out period. The 20L:4D ducks had a more efficient feed conversion ratio (P < 0.02). The 20L:4D ducks were less stressed, as indicated by reduced plasma corticosterone concentration, heterophil to lymphocyte ratio, and composite asymmetry score (P < 0.02), and elevated humoral immune response to a Newcastle Disease Virus vaccine (P = 0.035) compared to 16L:8D ducks. These results indicated ducks reared under the 20L:4D photoperiod had more efficient nutrient metabolism and stronger humoral immune response to a Newcastle Disease Virus vaccine due to improved FCR and decreased stress and the effects of stress compared to the 16L:8D photoperiod group. Fear response data from this study was considered inconclusive, and future investigation is still required to elucidate how various photoperiod schedules influence the fear response of Pekin ducks. The results of this study emphasize the need for appropriate, species-specific artificial photoperiods in modern grow-out facilities to maximize the production of Pekin ducks while also reducing stress.