Two mouse lines selected for large litter size display different lifetime fecundities

Area of Science:

• Animal Science
• Reproductive Biology
• Genetics

Background:

• Lifetime fecundity is crucial for livestock productivity, with mouse models offering insights.
• Previous studies established mouse lines selected for large first litter size.

Purpose of the Study:

• To compare lifetime reproductive performance of mouse lines selected for large first litter size (FL1, FL2) against control (ctrl) and lines selected for high body weight (DU6) or protein mass (DU6P).
• To test if selection for large first litter size enhances overall lifetime fecundity.

Main Methods:

• Comparative study of five mouse lines: FL1, FL2, ctrl, DU6, and DU6P.
• Evaluation of lifetime litter counts, average litter size, and total offspring per female.
• Assessment of general health in high-fertility lines.

Main Results:

• FL1 and FL2 mouse lines showed significantly higher lifetime reproductive output than DU6 and DU6P lines.
• FL1 females produced the highest number of pups per lifetime (85.7/female).
• FL2 exhibited large litter sizes initially but a reduced number of litters; litter size declined post-first litters in most lines.

Conclusions:

• Selection for large first litter size in mice leads to varied lifetime reproductive fitness.
• FL1 and FL2 mouse lines serve as valuable models for studying lifetime productivity and longevity in agriculturally important species.