Improving uniformity of growth by mating and selection strategies in rainbow trout

Abstract Text: Minimal variation in fish growth increases profit of fish farming and improves fish welfare. Uniformity can be increased by reducing additive genetic and residual variation. We first present a mating strategy to create a production stock that has only 38% of the original genetic variance, and assuming heritability of 0.26 for body weight of rainbow trout, 84% of the original phenotypic variance. An experimental test confirmed that phenotypic variance can be indeed reduced to 80% of the variation in the original breeding programme. Secondly, genetic CV for residual variation in body weight was notable (37%). Hence, one generation of sib selection for reduced residual variation is expected to reduce phenotypic variance to 87-89% of the original phenotypic variance. Both methods aid to produce more uniform populations for on-growing, while simultaneously maintaining genetic variation in the nucleus.

Keywords:

additive genetic variance

heterogeneity of residual variance

relationships

rainbow trout