Gestational Tryptophan Fluctuation Altering Neuroembryogenesis and Psychosocial Development in chickens

Authors: HUANG, XIAOHONG - Purdue University; FENG, ZHENDONG - Qingdao University; Cheng, Heng-Wei

Submitted to: Cells
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2022
Publication Date: 4/8/2022
Citation: Huang, X., Feng, Z., Cheng, H. 2022. Gestational Tryptophan Fluctuation Altering Neuroembryogenesis and Psychosocial Development in chickens. Cells. https://doi.org/10.3390/cells11081270.
DOI: https://doi.org/10.3390/cells11081270

Interpretive Summary: Chickens show aggression towards conspecifics for establishing social dominance rank within a flock. As a socially transmitted learning behavior, aggression can become bullying when a chicken or multiple chickens peck repetitively to others. This perspective article addresses current knowledge about excess tryptophan supply during pregnancy and how it affects the sociometric status in bullying via modifying the gut microbiota and brain function. The current findings indicate that administration of tryptophan reduces aggressiveness in chickens before and during adolescence. These results may provide insights for animal scientists to develop management strategies to reduce injurious behaviors in farm animals.

Technical Abstract: Tryptophan (Trp), as the sole precursor of serotonin, mainly derived from diets, is essential for neurodevelopment and immunomodulation. Gestational tryptophan fluctuation may account for the maternal-fetal transmission in determining neuroembryogenesis with long-lasting effects on psychological development. However, it is not clear how the fluctuation in mother-child transmission regulates the neuroendocrine development and gut microbiota composition in progeny. Tryptophan metabolism in pregnant women is affected by multiple factors, such as diets (Trp-enriched or -depleted diet), emotional mental stages (anxiety, depression), health status (hypertension, diabetes), and social support as well as stress level and management skills. Recently, we have developed a non-mammal model to rationalize those discrepancies without maternal effects. This perspective article outlines the possibility and verified the hypothesis in bully-victim research with this novel model: 1). Summarizes the effects of the maternal tryptophan administration on the neuroendocrine and microbial development in their offspring; 2). Highlights the inconsistency and limitations in studying the relationship between the gestational tryptophan exposure and psychosocial development in humans and viviparous animals; and 3). Shows that embryonic exposure to tryptophan and its metabolite modify bullying interactions in the chicken model. With the current research on the biomechanisms underlying the bully-victim interaction, the perspective article provides novel insights for developing appropriate intervention strategies to prevent psychological disorders among individuals, especially those who experienced prenatal stress, by controlling dietary tryptophan and medication therapy during pregnancy.