March 21, 2018

Interpretive Summary: Artificial Light and Biological Responses of Broiler Chickens: Dose-Response

Interpretive Summary: Artificial light and biological responses of broiler chickens: dose-response.

By: Jackie Walling

Living a productive life is all about balance and that is what the authors Yang et al , (2018) concluded about managing artificial light intensity in a broiler chicken environment from their study titled “Artificial light and biological responses of broiler chickens: dose-response.”  The researchers looked at how the intensity of artificial light affected the health of broiler chickens by evaluating five specific measures: body weight (BW), feed intake (FI), feed conversion ratio (FCR), mortality, and uniformity.

Research regarding effects of light intensity on the environment of broiler chickens is conflicting.  To evaluate, researchers performed meta-analysis (statistical review of many studies) to review and further analyze the available data.  

Specifically, researchers examined three levels of light intensity; low (less than 5 lux), moderate (10-30 lux), and high (greater than 30 lux) and evaluated the responses of the chickens.

The percentage of change from the ideal body weight gain did not significantly change when chickens were raised in environments with at least 1 lux of light intensity present.  Anything below 1 lux saw significant negative effects on the change in percentage for body weight.

Feed intake measures the amount of food eaten by the chickens.  A moderate level of intensity projected on the chickens showed a decreasing change in the FI while a high level of intensity caused the FI to increase significantly.  Similar to the FI, the Feed Conversion Ratio describes the amount of feed needed per kilogram of bodyweight gain and should be kept to a minimum in order to run an efficient business.  The three groups of light intensity had no significant effects, but a minimal quadratic relationship was observed within the high intensity level in the range of 50-180 lux.

Mortality measures the amount of death sustained in a flock.  Both moderate and high levels of light intensity significantly increased mortality. 

Uniformity proves to be an important factor when raising broiler chickens.  When a flock lacks uniformity, it requires more maintenance to manage the chickens growing at different rates.  A moderate level of light intensity increased uniformity while a high level depressed uniformity.

Several other factors such as processing characteristics, metabolic characteristics, and welfare problems were assessed and found to have varying results which are located in the full article found here.

Looking at the results as a whole picture, the key to creating a positive living environment for maximum broiler chicken growth is developed through identifying the correct artificial light intensity levels.  If one looks at the effects of the high group alone, the level of intensity has a significant impact on a flock because it causes an increase in mortality and a decrease in uniformity.  Therefore, the living conditions should stay below 30 lux.  Looking further, it was found that body weight was affected when intensity slunk below 1 lux.  Welfare problems also appeared below 5 lux.  With that information, the authors suggest that maintaining a minimum of 5 lux is the ideal living environment and adjustments higher should be made by monitoring the health of the chickens.  To read the full description of the results, go to the Journal of Animal Science.