# Molecular response in the pectoral muscles and livers of broiler chickens to mitochondrial stimulation by in ovo administration of prebiotics

## TL;DR

This study explores how giving prebiotics to chicken embryos affects mitochondrial activity in their muscles and livers, potentially improving growth and health.

## Contribution

The study introduces in ovo prebiotic administration as a novel strategy to modulate mitochondrial function in broiler chickens.

## Key findings

- In ovo prebiotic administration altered gene expression in pectoral muscles and livers of chickens.
- XOS4 group showed significantly greater water loss in pectoral muscles.
- Mitochondrial gene expression changes were tissue-specific depending on prebiotic type.

## Abstract

Mitochondria are the primary sites for adenosine triphosphate production through oxidative phosphorylation, thus supporting the high metabolic demands of avian physiology. By administering prebiotics in ovo, the aim was to analyse how an early host-supporting strategy can modulate mitochondrial activity and affect the physicochemical composition of the pectoral muscles of chickens.

Three hundred incubated Ross 308 broiler eggs were injected: 60 with 0.2 mL of 0.2 mmol/L physiological saline (control group), and 60 each with 0.5 mg of xylotriose (XOS3 group), xylotetraose (XOS4 group), mannotriose (MOS3 group) or mannotetraose (MOS4 group) carried in 0.2 mL of physiological saline. On day 42 after hatching, the liver and pectoral muscle were collected from eight individuals from each group after sacrifice, and the muscle was evaluated physicochemically. Relative mitochondrial DNA (mtDNA) copy numbers were analysed in a real-time quantitative PCR (qPCR). Gene expression was determined by a reverse-transcription qPCR (RT-qPCR) for a mitochondrial gene panel.

The experimental factor was not shown to affect pectoral muscle weight. Water loss was significantly greater in the XOS4 group’s muscles. The overall mtDNA copy number was stable in both tissues. The XOS3 and MOS4 groups’ gene expression was significantly changed in pectoral muscle. Contrastingly, the XOS4 and MOS3 groups’ gene expression was more altered in the liver. Statistically significantly different expression was detected of the CS, EPX, CYCS, TFAM and NRF1 genes in pectoral muscles and of all tested genes in livers.

The potential of in ovo prebiotic administration is indicated as a strategic approach to optimise mitochondrial function, ultimately contributing to better growth rates and enhanced health in broiler chickens.