Nervous necrosis virus (NNV) is the causative agent of viral nervous necrosis in freshwater and marine fishes. In this study, NNV circulating among wild and farmed Nile tilapia (Oreochromis niloticus) was genetically and morphologically characterized using reverse transcription polymerase chain reaction (RT-PCR), sequencing analysis, and transmission electron microscopy (TEM). Brain, eye, and other organ (spleen, kidney, heart, and liver) specimens were collected from 87 wild (66) and farmed (21) Nile tilapia fish during their adult or juvenile stage at different localities in Qena and Sohag governorates in southern Egypt. Among them, 57/87 fish showed suspected NNV clinical signs, and 30/87 were healthy. The results revealed that NNV was detected in 66 out of 87 fish (58.62% in the wild and 17.24% in farmed Nile tilapia by RT-PCR), and the prevalence was higher among diseased (55.17%) than in healthy (20.69%) fish. NNV was detected in the brain, eye, and other organs. Using TEM, virion size variations based on the infected organs were observed. Nucleotide sequence similarity indicated that NNVs had a divergence of 75% from other fish nodaviruses sequenced in Egypt and worldwide. Phylogenetic analysis distinguished them from other NNV genotypes, revealing the emergence of a new NNV genotype in southern Egypt. In conclusion, NNV is circulating among diseased and healthy Nile tilapia, and a new NNV genotype has emerged in southern Egypt.
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http://dx.doi.org/10.1007/s10123-023-00406-5 | DOI Listing |
Aquat Toxicol
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Department of Biology, Concordia University, 7141 Sherbrooke St. West, Montreal, Québec H4B 1R6, Canada.
Microplastics, particles between 0.001 and 5 mm in diameter, are ubiquitous in the environment and their consumption by aquatic organisms is known to lead to a variety of adverse effects. However, studies on the effects of microplastics on prey fish have not shown consistent trends, with results varying across species and plastic type used.
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January 2025
Buginyanya Zonal Agricultural Research and Development Institute, National Agricultural Research Organization (NARO), Mbale P.O. Box 1356, Uganda.
() aquaculture continues to significantly contribute to the growth of the aquaculture sector in Uganda. However, its production is beset by erratic and unreliable seed supply. Also, most hatcheries practice inbreeding of broodstock, resulting in inferior seed characterized by low growth rates.
View Article and Find Full Text PDFAntioxidants (Basel)
January 2025
School of Animal Technology and Innovation, Institute of Agricultural Technology, Suranaree University of Technology, 111 University Avenue, Muang, Nakhon Ratchasima 30000, Thailand.
Due to its lack of the L-gulonolactone oxidase () enzyme, Nile tilapia is unable to synthesize vitamin C; thus, it requires an adequate level of exogenous vitamin C in its diet. To enhance antioxidant properties and vitamin C-related effects, we employed recombinant technology to integrate the -encoding gene into the chromosome. In this study, fish were divided into four groups: those fed with a basal diet (CON), a basal diet + vitamin C (VC), a basal diet + wild-type (BS), and a basal diet + recombinant (BS+GULO).
View Article and Find Full Text PDFVet Sci
January 2025
Graduate Program in Animal Science, Federal University of Paraná, 1540 Rua dos Funcionários, Cabral, Curitiba 80035-050, PR, Brazil.
Corn and soybeans are commodities and ingredients of global interest, whose prices fluctuate based on global demands. In this sense, this study aimed to assess ora-pro-nóbis ( leaf meal (OLM) as an alternative to be included in the diets of Nile tilapia (). The optimal inclusion level of OLM in tilapia diets is investigated herein, aiming to improve their growth performance and health.
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Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai 201306, China; Marine Biomedical Science and Technology Innovation Platform of Lin-gang Special Area, Shanghai 201306, China. Electronic address:
Temperature fluctuations challenge ectothermic species, particularly tropical fish dependent on external temperatures for physiological regulation. However, the molecular mechanisms through which low-temperature stress impacts immune responses in these species, especially in relation to chromatin accessibility and epigenetic regulation, remain poorly understood. In this study, we investigate chromatin and transcriptional changes in the head kidney and thymus tissues of Nile tilapia (Oreochromis niloticus), a tropical fish of significant economic importance, under cold stress.
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