Relationships between growth and disease resistance in rainbow trout, Oncorhynchus mykiss (Walbaum)

Abstract

Rainbow trout from 23 families were evaluated for growth and resistance to the bacterial coldwater disease (BCWD) caused by Flavobacterium psychrophilum and infectious haematopoietic necrosis (IHN) caused by IHN virus. Average family weights were between 161 and 263 g with an average of 225 g at 213 days post-fertilization with specific growth rates ranging from 2.37 to 2.88. Per cent survival of fish challenged with F. psychrophilum was between 18% and 100%, while for those challenged with IHNV, the range was between 12% and 93%. Significant positive correlations were found for end body weight and resistance to IHN (P < 0.05) and for early body weight and resistance to BCWD (P < 0.1). However, no significant correlations were detected between resistance to both pathogens or disease resistance and overall genetic diversity or diversity within the major histocompatibility locus.

Genetic variation underlying resistance to infectious hematopoietic necrosis virus in a steelhead trout (Oncorhynchus mykiss) population

“…However, it is unclear whether there is a relationship between fish length at a specific age and IHNV resistance. Overturf et al (2010) examined the phenotypic correlation between size and resistance to IHNV in rainbow trout and only found a positive correlation for older fish (213 d post-fertilization, 224.7 g), but not for younger fish. Additionally, Barroso et al (2008) determined that the 2 traits were genetically independent in rainbow × Yellowstone cutthroat trout crosses.…”

Analysis of host genetic diversity and viral entry as sources of between-host variation in viral load

“…Host genetic diversity and stochasticity in the viral entry process are often hypothesized as the main factors driving variation in viral burdens between hosts (Brault et al, 2010; Capparelli et al, 2009; Fellay et al, 2007; Howey et al, 2009; Kaslow et al, 2005; Matthews et al, 2006; Overturf et al, 2010; Pelak et al, 2010). However, many systems are limited in their ability to explicitly quantify the role of these factors in regulating viral load variation.…”

Differential resistance to edwardsiellosis in rohu (Labeo rohita) families selected previously for higher growth and/or aeromoniasis-resistance

“…The survival range of 0 to 94.74% against edwardsiellosis observed in rohu families in the present study also indicated a wide variation in their susceptibilities to the disease. Similar observations were also made in Atlantic salmon (Salmo salar) challenged with A. salmonicida (Marsden et al 1996;Odegard et al 2006), rohu challenged with A. hydrophila (Sahoo et al 2004) psychrophilum in rainbow trout (Silverstein et al 2009;Overturf et al 2010). Disease resistance can be evaluated through different traits/tests obtained from a controlled challenge study.…”