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Published on: December 16, 2022
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Selection for efficiency of feed utilization in growing mice.
E Yüksel1, W G Hill, R C Roberts
1Institute of Animal Genetics, West Mains Road, Edinburgh, Scotland.
Summary
Selecting mice for better feed efficiency improved their growth and fatness. This occurred regardless of whether mice were fed freely or a restricted amount, showing consistent genetic responses in feed efficiency.
Area of Science:
- Animal Science
- Genetics
- Animal Nutrition
Background:
- Feed efficiency is a key trait in animal production.
- Understanding genetic selection responses under different feeding regimes is crucial for optimizing livestock.
- Previous studies have explored feed efficiency but rarely compared fixed intake versus ad libitum selection.
Purpose of the Study:
- To investigate the effects of selection for feed efficiency on mice under two distinct feeding regimes: ad libitum and fixed intake.
- To determine the realized heritability of feed efficiency.
- To analyze the impact of selection on growth, appetite, and carcass composition.
Main Methods:
- Mice were selectively bred for feed efficiency over 7-8 generations.
- Two feeding regimes were used: ad libitum and a fixed intake (10% below ad libitum).
- Mice were tested on both regimes in terminal generations, and carcasses were analyzed.
Main Results:
- Realized heritability for feed efficiency averaged 13%.
- Significant improvements in feed efficiency were observed in both selection lines (E and L), with the fixed intake line showing a larger response.
- Selection for efficiency increased fatness in mice under both feeding regimes.
Conclusions:
- Selection for feed efficiency is effective under both ad libitum and fixed intake conditions.
- Selection for feed efficiency leads to increased fatness, irrespective of the feeding regime.
- The genetic basis for improved feed efficiency appears consistent across different feeding strategies.
