Publication details
Immunocompetence and parasite infection in hybrids of roach (Rutilus rutilus) and common bream (Abramis brama)
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| Year of publication | 2016 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Hybrid heterosis may underlie the success of the hybrid vigour (measured for example as hybrid resistance against parasites). Nevertheless, hybridization may also disrupt the system of host-parasite gene co-adaptation. As the result, different parasite load in parental species and hybrids is expected. Hybrids with features inherited from both parental species may express different physiology and immunity when compared to those of their parental species. Consequently, it also affects parasite infection and the composition of parasite communities in the hybrid fish hosts. For this study, all metazoan parasites were collected from common bream (Abramis brama), roach (Rutilus rutilus) and their respective hybrids during spring and autumn 2011, 2012 and 2013. All fish specimens were identified using morphological traits and molecular markers (partial mitochondrial cyt b gene and 12 microsatellite loci). Basic physiological indexes were calculated to measure fish condition, vigour and immunocompetence. The aim of this study was to compare the physiological indexes, hematological parameters and selected measures of immunity between parental species and their hybrids and to search for the potential associations between host physiology (and immunity) and parasite load. Spleen-somatic (SSI) and gonado-somatic (GSI) indexes were significantly affected by hybridization. We found that total parasite infection correlated negatively with the SSI in hybrid females and males of common bream. The positive relationship between SSI and the hepato-somatic index (HSI) was found for common bream. The positive relationship between HSI and total parasite infection in males of roach was found, but this relationship was not evidenced in common bream and hybrids. GSI and lysozyme activity were positively correlated to total parasite infection in males of common bream, nevertheless, both HSI and SSI were negatively correlated to total parasite load in this fish group. In addition, lysozyme activity was also positively correlated to parasite infection in females of common bream. The positive correlation between lysozyme activity and condition factor, and negative correlation between SSI and total parasite infection were also found in hybrid females. Interestingly, oxidative burst activity correlates negatively with endoparasites in hybrid fish males. |
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