Effect of Tryptophan Supplementation Levels on the Cecal Microbial Composition, Growth Performance, Immune Function...

Area of Science:

• Animal Nutrition and Metabolism
• Gut Microbiome Research
• Poultry Science

Background:

• Tryptophan (Trp) is an essential amino acid for poultry, impacting growth, immunity, and gut health.
• Gut microbes metabolize Trp, influencing host physiology, but effects of excessive Trp are understudied.

Purpose of the Study:

• To investigate the impact of varying dietary Trp levels on broiler chicken performance, immunity, and antioxidant status.
• To correlate host responses with cecal microbiota composition and function.

Main Methods:

• Broiler chickens were fed diets with 0.23%, 0.29%, or 0.35% Trp.
• Production performance, immune indices (thymus), and antioxidant levels (serum SOD) were measured.
• Cecal microbiota was analyzed using metagenomic sequencing and correlated with host parameters.

Main Results:

• 0.35% Trp impaired weight gain and feed intake; 0.29% Trp increased thymus index and SOD without affecting growth.
• Trp supplementation modulated gut microbiota, decreasing harmful bacteria and increasing beneficial and Trp-metabolizing microbes.
• Trp levels correlated with body weight, thymus index, and SOD, linked to specific Trp-utilizing microorganisms and their metabolic pathways.

Conclusions:

• A moderate Trp level (0.29%) enhances metabolic markers and immunity without compromising broiler performance.
• These benefits are likely mediated by beneficial gut microbes and their Trp metabolic pathways.