Genotype by environment interactions in feed efficiency of Pacific abalone (Haliotis discus hannai) reared at different water temperatures

Genetic improvement of feed efficiency (FE) in Pacific abalone (Haliotis discus hannai) can improve farming efficiency and reduce costs. Temperature has important effects on the feeding and growth of abalone, and genotype by environment (G x E) interactions should be considered in selecting breeding programs for genetic gain. To improve the selection strategy, FE performance, genetic parameters, and G x E interactions of abalone were measured and evaluated at 17 degrees C, 21 degrees C, and 27 degrees C. The feed efficiency ratio (FER) showed a similar degree of phenotypic variation at all three temperatures, with the best phenotypic performance at 17 degrees C. The heritability of FER was high (0.55-0.72) and relatively stable at different temperatures, while the heritability of residual feed intake (RFI) changed with temperature and was 0.21 at 27 degrees C. The FER had a high positive genetic correlation (0.68-0.75) with specific growth rates (SGRs) and a genetic correlation ranging from 0.32 to 0.81 with food intake (FI). RFI had a low genetic correlation with growth (-0.43 to 0.03) and a high genetic correlation (0.42-0.82) with FI. The between-environment genetic correlations for FI, weight gain (WG), and FER were high (0.78-0.94). However, the RFI showed significant G x E interactions at different temperatures. By combining the performance results, genetic parameters, and G x E interactions, it was found that FER was the most suitable trait for improving abalone FE at variable temperatures in breeding programs. This study provides guidance on selective breeding strategies to improve abalone FE.