The impact of early-life cecal microbiota transplantation on social stress and injurious behaviors in egg-laying chickens

Authors: FU, YUECHI - Purdue University; HU, JIAYING - Purdue University; ZHANG, HUANMIN - US Department Of Agriculture (USDA); ERASMUS, MARISA - Purdue University; JOHNSON, TIMOTHY - Purdue University; Cheng, Heng-Wei

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2024
Publication Date: 2/26/2024
Citation: Fu, Y., Hu, J., Zhang, H., Erasmus, M.A., Johnson, T.A., Cheng, H. 2024. The impact of early-life cecal microbiota transplantation on social stress and injurious behaviors in egg-laying chickens. International Journal of Molecular Sciences. https://doi.org/10.3390/microorganisms12030471.
DOI: https://doi.org/10.3390/microorganisms12030471

Interpretive Summary: A plethora of studies have evidenced that the gut microbiota profoundly influences host brain function and behavioral characteristics in humans and various animals. In laying hens, it has been reported that injurious behaviors (such as aggressive pecking, feather pecking, and cannibalism) are associated with dysfunction of the gut-brain axis. This study further investigated the effects of early-life transplantation of different cecal contents on aggressiveness and related behaviors in chickens. Cecal bacterial profiles of two divergently selected inbred genetic lines (donors) were analyzed, then orally transferred separately into newly hatched male chicks of a commercial layer strain (recipients). Effects of cecal microbiota transplantation on growth, physiology, and behavior were examined in the recipient birds. This study first evidenced that social stress and related behaviors in chickens can be reduced by modification of gut microbiota composition and brain function. The results provide new insights for understanding the cellular mechanisms of the microbiota in regulating social stress and stress-induced abnormal behavior and provide a novel strategy for reducing injurious behaviors and improving welfare in egg-laying chickens.

Technical Abstract: Injurious behaviors (i.e., aggressive pecking, feather pecking, and cannibalism) in laying hens are a critical issue facing the egg industry due to increased social stress and related welfare issues as well as economic losses. In humans, stress-induced dysbiosis increases gut permeability, causing neuroinflammation and related neuropsychiatric disorders via the microbiota-gut-brain axis, consequently increasing the frequency and intensity of aggression and related violent behaviors. Restoration of imbalanced gut microbial composition has become a novel treatment strategy for mental illnesses, such as depression, anxiety, bipolar disorder, schizophrenia, impulsivity, and compulsivity. A similar function of modulating gut microbial composition following stress challenge may present in laying hens. The avian cecum, as a multi-purpose organ, has the greatest bacterial biodiversity (bacterial diversity, richness, and species composition) along the gastrointestinal tract, with vitally important functions in maintaining physiological and behavioral homeostasis, especially during periods of stress. To identify the effects of the gut microbiome on injurious behaviors in egg-laying chickens, we have designed and tested the effects of transferring cecal contents from two divergently selected inbred chicken lines on social stress and stress-related injurious behaviors in recipient birds of a commercial layer strain. This article reports the outcomes from a multi-year study: modification of gut microbiota composition to reduce injurious behaviors in egg-laying chickens. An important discovery of this corpus of experiments is that injurious behaviors in egg-laying chickens can be reduced or inhibited through modifying the gut microbiota composition and brain serotonergic activities via the microbiota-gut-brain axis, without donor-recipient genetic effects.