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The aim of this study is to report the occurrence of Lymphocystivirusin Brazilian ornamental fish. From 25 ornamental fish species submitted for molecular diagnosis, only one sample (Pomacanthus imperator) was positive, and its viral nucleotide sequence obtained clustered with sequences of genotype VII. To our knowledge, this is the first report on the genetic characterization of Lymphocystivirusin Brazil.

Cyprinid herpesvirus 3has a worldwide distribution and presents high mortality rates in species of Cyprinus carpio, causing serious economic loss to the global aquaculture industry. The description of this infection in other ornamental fish species is still limited. For this purpose, 100 ornamental fish from 24 different species were tested by PCR for Cyprinid hespesvirus 3and the positive samples represented 6% of the tested samples. Phylogenetic reconstruction, based on the Thymidine Kinase gene, revealed the existence of two distinct clades. One clade grouped a Brazilian sample with European and Asian genotypes of CyHV-3 and a second clade, containing only Brazilian sequences described in this study. All of the Brazilian sequences showed identity values greater than 97.7% when compared to each other. This is the first report of the occurrence of Cyprinid herpesvirus 3in ornamental fish species in Brazil. These results in association with further studies of viral isolation and characterization can help in establishing effective surveillance and disease control program.

Triploid fish are becoming increasingly popular in commercial aquaculture due to their sterility, which results in improved meat quality and better growth rates as a result of the lack of sexual maturation. However, triploid fish are generally perceived as being more susceptible to diseases and less able to cope with suboptimal environmental conditions. The present study aimed to evaluate the effects of triploidy on the expression of C-type and G-type lysozymes (LysC and LysG) in lambaris (Astyanax lacustris) that were challenged with a pathogenic strain of Aeromonas jandaei. The animals were induced to triploidy as described in the literature. We infected 10 diploid and 10 triploid fish with 104CFU of A. jandaeiin 0.1 mL of PBS by intraperitoneal injection, a dose capable of triggering an immune response in the animals. Fish from the control groups were inoculated with 0.1 mL of sterile PBS. Molecular cloning of Lysozyme C and Lysozyme G was performed to characterize these genes, and the analysis of gene expression for LysC and LysG of A. lacustrisdiploids and triploids was conducted using qPCR. The collected data revealed that there were no significant differences in basal expression between diploid and triploid uninfected fish. However, the challenged fish of both ploidies exhibited an increase in expression compared to the control group. The results of study indicate that infected diploid fish exhibit significantly higher lysozyme expression in the spleen compared to infected triploid fish. While basal lysozyme expression levels between diploid and triploid fish remain unaffected, our findings suggest that triploidy may lower lysozyme expression in response to infection, with diploid fish exhibiting higher levels of expression.