Mitigating feather pecking behavior in laying poultry production through tryptophan supplementation

Abstract

Feather pecking behavior is regarded as the most serious welfare concern in poultry layer production. The cause of feather pecking is partly due to the nutrient-deficient diets that further depletes the tryptophan levels in the animal’s system. Tryptophan is an essential amino acid and thus, cannot be synthesized in the body of animals, including poultry. This amino acid can be metabolized through three pathways. Tryptophan metabolism produces important metabolites: serotonin and melatonin. Tryptophan affects hormone secretion in poultry. Thus, it affects poultry’s psychological status, which eventually leads to feathers’ pecking. The application of tryptophan as a feed additive can improve poultry performance and alleviate feather pecking behavior or stress response in poultry production. This is achieved through indole pathways and mostly through the Tryptophan-Kynurenine pathway. This review paper aims to provide detailed information regarding the performance of tryptophan on feather pecking behavior, particularly in laying poultry animals.