Differences in susceptibility to Mycobacterium chelonae in zebrafish (Danio rerio) lines commonly used in scientific research

Abstract

Mycobacteriosis is one of the most common diseases encountered in laboratory zebrafish. These infections can present a problem to researchers using zebrafish because they may introduce unknown experimental variables. Whilst differences in severity of infections between species of Mycobacterium infecting zebrafish have been well documented, little is known about differences in susceptibility between zebrafish lines. Previous surveys have found higher prevalence in the TU zebrafish line relative to other lines, suggesting that there may be underlying genetic differences in susceptibility. This study investigates Mycobacterium chelonae H1E2‐GFP infections in four different zebrafish lines commonly used in research (AB, 5D, casper and TU). Fish were exposed to a labelled (green‐fluorescent protein (GFP)) strain of M. chelonae by intraperitoneal injection, and infection status was evaluated after 10 weeks. Visualization of GFP in euthanized fish and histology were used as endpoints. In GFP images, severity was assessed by image analysis, and in histological sections, counts of granulomas containing acid‐fast bacteria were used. Results indicated differences in severity of infections between lines, but no significant differences in prevalence.

Fluoxetine and Curcumin Prevent the Alterations in Locomotor and Exploratory Activities and Social Interaction Elicited by Immunoinflammatory Activation in Zebrafish: Involvement of BDNF and Proinflammatory Cytokines

“…Males and females exhibit characteristic biological differences that include phenotypic traits. Differences between males and females cause changes in biochemical processes, disease susceptibility, and behavior. , In line with these observations, studies with zebrafish demonstrate that there are sex differences in behavioral, physiological, and neuropharmacological responses, evidencing, mainly, that there is a greater sensitivity of females in response to different experimental protocols used. , Female rats injected with the proinflammatory cytokine IL1b stopped mating with male rats to avoid a litter with reduced chances of survival to reproductive age. , Also, female zebrafish are more sensitive to the inflammatory response after infection due to the development of ovarian granulomes, which may reduce fecundity and/or contaminate the offspring when the eggs are released . Therefore, the decreased social preference of female fish found in our study might be related to reproductive aspects, such as the concern for contamination of the offspring and the protection of the shoal.…”

“…35,40 Also, female zebrafish are more sensitive to the inflammatory response after infection due to the development of ovarian granulomes, which may reduce fecundity and/or contaminate the offspring when the eggs are released. 41 Therefore, the decreased social preference of female fish found in our study might be related to reproductive aspects, such as the concern for contamination of the offspring and the protection of the shoal. However, this hypothesis deserves further investigation.…”

Identification of Mycobacterium chelonae from Lined Seahorse Hippocampus erectus and Histopathological Analysis

“…Therefore, future work needs to investigate the relationship between the pathological features seen in seahorses inoculated with different concentrations of M. chelonae. In addition to the liver, kidney, and intestine, ovarian lesions were also observed in diseased seahorses, which means that M. chelonae could affect the reproductive rate of seahorses; similar results were also observed in zebrafish [32].…”

“…Atlantic salmon Salmo salar, Yellow perch Perca flavescens, Yellow stingray Urobatis jamaicensis, and Russian sturgeon Acipenser gueldenstaedtii [25][26][27][28][29][30][31]. Although many fish species can be infected with M. chelonae, studies have shown that there are differences in susceptibility to M. chelonae among different species and even different lines of the same species [32]. Yellow groupers Epinephelus awoara are also reared in seahorse farms but do not become infected with M. chelonae.…”