Selection strategies for body weight and reduced ascites susceptibility in broilers

Area of Science:

• Animal Science
• Genetics
• Poultry Science

Background:

• Ascites syndrome is a metabolic disorder in broilers causing significant economic losses and welfare issues.
• Genetic factors contribute to broiler susceptibility to ascites, presenting opportunities for genetic selection.
• Current breeding practices focused solely on body weight (BW) may exacerbate ascites susceptibility.

Purpose of the Study:

• To evaluate alternative selection strategies for improving BW and ascites resistance in broilers.
• To compare the outcomes of current selection practices with strategies incorporating ascites-related traits and genetic information.
• To quantify the impact of different breeding schemes on BW gain, ascites susceptibility, and inbreeding rates.

Main Methods:

• Utilized deterministic simulation to model five different breeding schemes.
• Investigated selection strategies including BW, ascites-related traits (hematocrit value (HCT) and right ventricle to total ventricular weight ratio (RV:TV)), and quantitative trait loci (QTL) information.
• Assessed trait measurements under normal and cold environmental conditions.

Main Results:

• Selection for BW alone resulted in a 130 g gain but increased ascites susceptibility.
• A strategy involving testing 50% of birds under cold conditions and including HCT and RV:TV data achieved 111.4 g BW gain with zero genetic response in ascites susceptibility.
• Scenarios incorporating QTL information demonstrated high effectiveness in controlling ascites susceptibility.

Conclusions:

• Breeding goals must integrate ascites resistance alongside growth traits to mitigate economic and welfare impacts.
• Environmental stress (cold conditions) can be utilized to identify susceptible birds for selection.
• Marker-assisted selection (MAS) using QTL information offers a powerful tool for managing ascites syndrome in broiler breeding programs.