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Fasting metabolic rate in hens. 2. Strain differences and heritability estimates
Poultry Science
|April 1, 1986
Summary
Rhode Island Red and Light Sussex hens show distinct fasting metabolic rates (FMR), with breed differences persisting after accounting for body weight and activity. Genetic factors significantly influence FMR in chickens.
Area of Science:
- Animal Science
- Poultry Genetics
- Metabolic Physiology
Background:
- Fasting metabolic rate (FMR) is a key indicator of energy expenditure in poultry.
- Understanding breed-specific FMR is crucial for optimizing feed efficiency and production in chickens.
- Previous research has not fully elucidated the genetic basis and breed variations in chicken FMR.
Purpose of the Study:
- To compare the fasting metabolic rate (FMR) between Rhode Island Red (RIR) and Light Sussex (SS) chicken breeds and their reciprocal crosses.
- To investigate the influence of body weight, feather loss, and activity on FMR.
- To estimate the heritability of FMR and assess the genetic component within these breeds.
Main Methods:
- Short-term measurements of FMR were conducted on RIR, SS, and their crosses between 40 and 60 weeks of age.
- FMR was analyzed considering body weight, feather loss, and activity levels.
- Heritability estimates for FMR were calculated using within-stock analyses.
Main Results:
- Significant differences in FMR were observed between RIR and SS breeds, with RIR exhibiting higher rates.
- FMR in reciprocal crosses fell between the parental means, indicating no significant heterosis effect on metabolic rate.
- Heritability estimates for FMR were moderately high, with a persistent genetic component even after adjustments for environmental factors.
Conclusions:
- Breed differences in FMR exist in chickens and are influenced by genetic factors.
- Adjustments for body weight, feather loss, and activity reduce heritability estimates but do not eliminate the genetic basis of FMR.
- The findings provide insights into the metabolic physiology and genetic architecture of FMR in poultry breeds.
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