Abstract: Lymphocystis disease caused by the lymphocystis disease virus (LCDV) infects numerous fish species including wild and farmed fish from several families. The LCDV is a DNA virus belonging to the family Iridoviridae. The virus usually causes benign, chronic infection characterized by macroscopic nodules located on the body, fins, and gills of fish, although other tissues may be infected occasionally. The disease normally does not cause significant mortalities, but massive infections leading to substantial mortalities have been reported in some aquacultured species such as sea bream (Sparus aurata), Olive flounder (Paralichthys olivaceus), Japanese seabass (Lateolabrax japonicus), and rockfish (Sebastes schlegeli). In this study, nodules from the fins of a largemouth bass (Micropterus salmoides) were subjected to pathological examination. Microscopic analysis of the wet mount and the histological analysis revealed the pathological alterations caused by the lymphocystis disease virus. Histopathological analysis indicated that the nodules contained encapsulated hypertrophic cells typical of the viral infection. The inoculum from the fin nodules produced cytopathic effects (CPEs) on Bluegill Fry (BF-2) cells, while no CPEs were observed in the Epithelioma Papulosum Cyprini (EPC) and Fathead Minnow (FHM) cell lines. These findings suggest that the causative agent of the fin infection in the largemouth bass is lymphocystis disease virus.Abstract: Lymphocystis disease caused by the lymphocystis disease virus (LCDV) infects numerous fish species including wild and farmed fish from several families. The LCDV is a DNA virus belonging to the family Iridoviridae. The virus usually causes benign, chronic infection characterized by macroscopic nodules located on the body, fins, and gills of fish, a...Show More
Abstract: In Ethiopia soil fertility and productivity has been decline due to excessive use of chemical fertilizer, top soil erosion and organic matter depletion. This laboratory and greenhouse study was conducted to isolate effective rhizobium strain and vermicompost rate to improve the crop yield and soil properties. It was carried out using Dosha variety in 2020 to 2021. The factorial combination of three rhizobium strains (non-inoculated, RS-17 and RS-1035) and four rates of vermicompost (0, 5, 10 and 15 ton ha-1) treatments were arranged in complete randomized design (CRD) with three replications. The result showed that rhizobium strains and vermicompost rate had brought significant (p<0.05) influence on the biological and chemical properties of soils. Sole application of maximum rate of vermicompost (15 ton ha-1) and rhizobium strain with RS-17 and RS-1035 significantly improve total number of microbial community. The crop inoculated by RS-17 responded the maximum number of rhizobium bacteria. Sole and combined application of 15 ton ha-1vermicompost with RS-1035 or RS-17 strains produced large sized, deep red and fast growing rhizobium bacteria. On the other hand, the treatment that received combined RS-17and 15 ton ha-1vermicompost was significantly improved soil’s pH by 6.2%, organic carbon (37.5%), available P (13.2%) and total N (1.5%) as compared with the control treatment. Moreover, it had the maximum microbial population (1.33×108cfu/g) and out of this 7.6×105cfu/g rhizobia population. However, to forward a compressive recommendation the experiment should be supported by field studies on different area soils.
Abstract: In Ethiopia soil fertility and productivity has been decline due to excessive use of chemical fertilizer, top soil erosion and organic matter depletion. This laboratory and greenhouse study was conducted to isolate effective rhizobium strain and vermicompost rate to improve the crop yield and soil properties. It was carried out using Dosha variety ...Show More