Age-related effect of high frequency LED lighting in laying hens Part 1: Blood Physiological Variables

Authors: Olanrewaju, Hammed; Purswell, Joseph - Jody; Evans, Jeffrey - Jeff; Collier, Stephanie; BRANTON, SCOTT - Retired ARS Employee

Submitted to: Canadian Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2023
Publication Date: 4/6/2023
Citation: Olanrewaju, H.A., Purswell, J.L., Evans, J.D., Collier, S.D., Branton, S.L. 2023. Age-related effect of high frequency LED lighting in laying hens Part 1: Blood Physiological Variables. Canadian Journal of Animal Science. https://doi.org/10.1139/cjas-2022-0119.
DOI: https://doi.org/10.1139/cjas-2022-0119

Interpretive Summary: The poultry industry is quickly increasing the efficiency of producing animal proteins which are commonly consumed by humans including eggs and meats. Advances include improved genetics and nutrition as well as changes in environmental management. In the past five decades, consumption of poultry eggs and meat has increased significantly, and this trend is expected to continue in the future due to the relative price-competitiveness compared to other animal protein products. However, concern among the public regarding animal well-being in food production systems continues to grow. There is a public perception that increased production efficiency takes a toll on the well-being of the animal. As the demand for animal protein products rises, increasing poultry production and production efficiencies will be critical to the continued viability of the U.S. poultry and livestock industries. To date, high frequency photostimulation has only been evaluated in laying hens through proprietary testing by the manufacturers. No evaluation has been conducted by independent scientists. Therefore, this study investigated the whole blood physiological parameters of laying hens reared under conventional lights and a novel high-frequency photostimulation system developed to improve growth and maximize egg production without compromising the welfare of laying hens. Most of these blood parameters in this study are indicators of health and systemic homeostasis. In each trial of 2 trials, we evaluated the age-related effect of high frequency LED lighting on physiological response in laying hens to evaluate effects on health and welfare. Results showed that lighting treatments had minor effects, but age was the most significant factor in bird response. All effects on physiological response remained within the normal range for chickens; no physiological indicators of stress (corticosterone) were elevated indicating that the high-frequency LED system did not affect hen welfare. These results contribute to our knowledge of the applicability of LED lighting systems for commercial poultry.

Technical Abstract: Light is a crucial environmental factor affecting hen development, welfare, and egg production. A novel lighting system using high frequency LED, developed to improve productivity in layer chickens, was assessed for commercial application. This study investigated the blood physiological variables of laying hens to high-frequency differential photostimulation. The study was a completely randomized design. In each of the 2 trials, a total of 320-layer pullets were obtained from a commercial farm at approximately 10 weeks of age (woa) and randomly allocated to 16 groups of 20 birds per group. Birds were weighed and randomly assigned to each of four cage banks in each 4 rooms with 80 birds per room. Treatments included the prototype LED lighting system and conventional 2700K LED bulbs. The prototype LED lighting system were installed in two rooms, and the conventional lighting system were employed in the remaining two rooms. Photoperiod for the prototype system was 24L:0D per the manufacturer’s recommendations and photoperiod for the conventional system followed the HyLine Management Guide. Blood samples (3 ml) were collected from the brachial wing vein into heparinized syringes within 45 s after birds were caught from 8 randomly selected birds per room for a total of 32 birds at each blood sampling day of placement (10 woa), prior to point of lay (15 woa), and at the end of the study (30 woa) for a total of 96 birds, which were then analyzed immediately for blood physiological variables. The remaining blood samples were centrifuged for plasma that was used for T3, T4, and CORT analysis. Results show that only a few physiological variables were affected by treatments, but woa had significant effects on most examined variables. Plasma corticosterone was not affected by treatments and woa, indicating absence of physiological stress. The results contribute to our knowledge of prototype LED light on blood physiological variables in layer hens, which does not negatively affect layer hens’ welfare.