Genotype by environment interaction for adult body weights of shrimp Penaeus vannamei when grown at low and high densitie

Abstract

-Shrimp is one of few marine species cultured worldwide for which several selective breeding programs are being conducted. One environmental factor that can affect the response to selection in breeding programs is the density at which the shrimp are cultured (low-medium-high). Phenotypic plasticity in the growth response to different densities might be accompanied by a significant genotype by environment interaction, evidenced by a change in heritabilities between environments and by a genetic correlation less than one for a unique trait between environments. Our goal was to understand whether different growth densities affect estimates of those genetic parameters for adult body weight (BW) in the Pacific white shrimp (Penaeus vannamei). BW heritabilities were significantly different between environments, with the largest at high density. These differences resulted from both an increased additive genetic variance and a decreased environmental variance when grown at high density. The genetic correlation between BWs at the two environmental conditions was significantly less than one. Whereas these results might be suggestive for carrying out shrimp selective breeding for BW under high density conditions, further understanding of genetic correlations between growth and reproductive traits within a given environment is necessary, as there are indications of reduced reproductive fitness for shrimp grown at high densities.Litopenaeus / heritability / body weight / density / genotype by environment interaction

Family growth response to different laboratory culture environments shows genotype-environment interaction in the sea urchin Strongylocentrotus intermedius

“…These suggest that culture environments would not conceal or exaggerate the variation of body weight in the family population. Similar results can be calculated from the results of studies on several aquatic animals such as gilthead seabream Sparus auratus (Navarro, Zamorano, Hildebrandt, Ginés, Aguilera & Afonso ), European whitefish Coregonus larvaretus (Quinton, Kause, Koskela & Ritola ) and shrimp Penaeus vannamei (Ibarra & Famula ). Therefore, the phenotypic variation change of sea urchins by Kelly () and Lawrence et al .…”

Interactive effects of family and stocking density on survival and growth of the sea urchin Strongylocentrotus intermedius

“…Actually, the p value (0.062) for body weight growth was almost significant. This result is consistent with those of Coman et al () ( P. japonicus families tested in densities of 48 and 144 individuals m −2 ) and Ibarra and Famula () ( P. vannamei families tested in densities of 5.9 and 400 individuals m −2 ). However, Tan et al () did not find a significant genotype by density (80 and 160 individuals m −2 ) interaction in growth of the shrimp L. vannamei .…”

Effect of the data family structure, tank replication and the statistical model, on the estimation of genetic parameters for body weight at 28 days of age in the Pacific white shrimp (Penaeus (Litopenaeus) vannamei Boone, 1931)

“…Many high heritability values found for growth in penaeid shrimp (>0.50) were obtained from designs/analyses that either ignored these maternal and common environmental effects (see e.g. Ibarra & Famula ) or have nil or few half‐sib families (see e.g. Benzie, Kenway & Trott ; Argue, Arce, Lotz & Moss ; Kenway, Macbeth, Salmon, McPhee, Benzie, Wilson & Knibb ), and hence dam and sire variance components may not be adequately separated.…”