# Effects of Trimethylamine Concentrations in Hatching Eggs on Chick Quality in Dwarf Hens

## TL;DR

Increasing trimethylamine in hatching eggs improves chick quality and survival by reducing bacterial risks without chemicals.

## Contribution

A novel dietary method to boost trimethylamine in eggs, enhancing chick quality and hatchability in dwarf hens.

## Key findings

- Higher yolk TMA concentrations improved hatchability and reduced chick abnormalities.
- Chicks from high-TMA eggs had lower early-life mortality rates.
- TMA content of ≥4 µg/g correlated with better Pasgar scores and yolk sac absorption.

## Abstract

Ensuring the successful hatching of healthy chicks and improving chick quality is crucial for the poultry industry. Chemical disinfectants have been traditionally used to protect hatching eggs from bacterial infection; however, these methods can harm the developing embryos and pollute the environment. In this study, we explored a safer and more natural approach of increasing the concentration of trimethylamine (TMA), which has antibacterial properties in eggs. We fed dwarf hens a specific dietary supplement to increase TMA concentrations in egg yolk and studied the effects on hatching eggs. The results show that eggs with a higher TMA had improved hatching rates and produced stronger, healthier chicks with fewer physical defects. Furthermore, these chicks exhibited lower mortality rates in early life. Our method offers a promising new approach by enhancing the antibacterial components inside hatching eggs, thereby improving chick survival and quality while potentially reducing reliance on external chemical treatments.

Microbial contamination of hatching eggs often leads to reduced hatchability and poor chick quality. As trimethylamine (TMA), a metabolite derived from dietary choline, has antimicrobial properties, increasing yolk TMA contents may increase bacterial resistance to eggs; however, the effects of TMA concentrations on chick quality remain unknown. Hence, this study was conducted to determine the effects of yolk TMA concentrations on the hatchability and chick quality of dwarf hens with different FMO3 genotypes. Hens (n = 140) were divided into control and experimental groups; the latter received choline chloride (2800 mg/kg) to elevate their yolk TMA concentrations. The TMA content, Pasgar score, hatchability, and post-hatching performance were evaluated. The results showed that choline supplementation significantly increased TMA concentrations in hens with AT and TT genotypes. Higher yolk TMA concentrations (≥4 µg/g) correlated with improved Pasgar scores and reduced abnormalities in vitality, navel, and yolk sac absorption. Hatchability peaked at 6.49 µg/g TMA, suggesting a threshold effect. Although the growth rate remained unaffected, chick mortality decreased in the high-TMA group. Therefore, moderate TMA concentrations can enhance egg antimicrobial defenses and improve reproductive performance. This strategy provides a biologically grounded alternative to traditional chemical disinfection in hatcheries.