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•Hg concentration in fish was below the maximum residual limit (MRL)•Hg levels in fish found in the following order: pelagic > benthic > demersal.•Both Se and Hg levels biomagnified ...in the food web along the Gulf of Mannar coast.•Se: Hg molar ratio was > 1, suggesting a protective effect of Se on Hg toxicity.•Health risk analysis (THQ/HI < 1) indicates fish collected from this region was safe.•Se-HBV and HBVse showed fishes were the surplus source of Se and mitigating Hg toxicity.
This study aimed to explore the concentrations of Se and Hg in marine fish along the Gulf of Mannar (southeast coast of India) and to assess related risks and risk-based consumption limits for children, pregnant women, and adults. Se concentrations in pelagic and benthic fish ranged from 0.278 to 0.470 mg/kg and 0.203 to 0.294 mg/kg, respectively, whereas Hg concentrations ranged from 0.028 to 0.106 mg/kg and 0.026 to 0.097 mg/kg, respectively. Se and Hg contents in demersal fish (Nemipterus japonicus) were 0.282 and 0.039 mg/kg, respectively. The lowest and highest Hg concentrations in pelagic fish were found in Scomberomorus commersoni and Euthynnus affinis whereas the lowest and highest Se concentrations in benthic fish were found in Scarus ghobban and Siganus javus. Se concentrations in marine fishes were found in the following order: pelagic > demersal > benthic whereas Hg concentrations were found in the following order: pelagic > benthic > demersal. The presence of Se in fish was positively correlated with trophic level (TL) and size whereas that of Hg was weakly correlated with TL and habitat and negatively correlated with size. Se risk–benefit analysis, the AI/RDI (actual intake/recommended daily intake) ratio was > 100 % and the AI/UL (upper limit) ratio was < 100 %, indicating that all fish have sufficient levels of Se to meet daily requirements without exceeding the UL. Hg level was below the maximum residual limit (MRL) of 0.5 mg/kg for most fish but it was 1 mg/kg in E. affinis and Lethrinus lentjan. The target hazard quotient (THQ < 1) and hazard index (HI < 1) imply that the consumption of fish poses no noncarcinogenic health risks. However, all examined fish had a mean Se/Hg molar ratio > 1, indicating that human intake of fishwas rather safe relative to Hg content. Health benefit indexes (Se-HBV and HBVse) with high positive values in all fish supported the protective effect of Se against Hg toxicity, suggesting the overall safety of fish consumption. The high Se/Hg ratio in fish could be attributed to the replacement of Se bound to Hg, thereby suppressing Hg toxicity and maintaining normal selenoprotein synthesis. This insight is useful for a better understanding of food safety analysis.
Myxozoan parasites pose huge threat to wild and cultured fishes and reported to cause heavy mortality, retarded growth and post-harvest quality degradation. It is one of the highly divergent groups ...of parasites which infects skin, gill, muscle, cartilage and internal organs of host fish and the severity of pathology varies depending on the water temperature, species of fish, site of tissue infection and immune resistance of the individual host. Most infections are difficult to treat, as they can easily evade host cellular and humoral defence mechanisms by proliferating or migrating through immune compromised sites of the host and forming large plasmodia encapsulated by the host cellular elements. This spore-forming parasite is harmless to humans but often detected in faecal samples of immunosuppressed humans. The incidences are mostly associated with the consumption of infected fish having a high concentration of spores which causes diarrhea and stomach pain. Currently, there are no immunostimulants or vaccines available for controlling these parasites, however, fumagillin is the drug of choice in fish for controlling this parasitic infection. Excessive usage of fumagillin causes tissue damage and retarded growth in fish, hence feed incorporation of this antibiotic in proper dose is essential for effective treatment. In this review detailed information on the diseases caused by myxozoan parasites in fishes and their zoonotic potential is discussed.
Recombination activating genes (RAGs) mediates the process of rearrangement and somatic recombination (V(D)J) to generate different antibody repertoire. Studies on the expression pattern of adaptive ...immune genes during ontogenic development are crucial for the formulation of fish immunization strategy. In the present study, Nile tilapia was taken to explore the relative expression profile of RAG genes during their developmental stages. The developmental stages of Nile tilapia, i.e., unfertilized egg, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28 and 30 days post-hatch (dph) and kidney, blood, gill, liver and spleen tissues from adult fish were collected and the cDNA synthesis was carried out. Gene specific primers for RAG-1 and RAG-2 of Nile tilapia were designed and their annealing temperature (Tm) was optimized by gradient PCR. Consequently, PCR was performed to confirm the specific amplification of RAG-1 and RAG-2 genes. Quantitative real-time PCR (qRT-PCR) gene expression of RAG-1 and RAG-2 were noticed in all the developmental stages; however, a significant increase was observed after 12 dph and peaked at 24 dph, followed by a gradual decrease until 30 dph. Tissue-specific gene expression profiling revealed that the highest expression of RAG-1 and RAG-2 was observed in the kidney, followed by spleen, gill, liver and blood. The findings of the study explored the suitable timing of lymphoid maturation that could be technically used for the adoption of strategies to improve disease resistance of fish larvae for mitigating larval mortality.
•The expression of RAG-1 and RAG-2 starts from the twelve days post hatch.•Kidney shows the abundance of RAG-1 mRNA.•The expression of RAG-1 is higher than RAG-2 across the tissues.
Meenatchi, S.; Iburahim, S.A.; Nayak, B.B.; Rathinam, R.B.; Paul, T.N.; Seenivasan, P.; Ramteke, K.; Ramanan, S.S.; and Anantharaja, K., 2024. A meta-analysis of artemia global research over seven ...decades (1949–2021).Brine shrimp are little planktonic crustaceans found all over the world in hypersaline habitats. Brine shrimp populations are found in numerous inland salt lakes and coastal salterns across the world. Scientometrics is a branch of statistics concerned with measuring and analyzing scholarly publications. The current study used a Web of Science database to thoroughly analyze and document the Artemia research output over the last seven decades. For this study, 9738 papers were examined using R software to evaluate the scientific productivity in this specified topic area. The global publishing share, rank, and evolution in terms of research and bibliometric indices, such as total citations, h index, and average number of citations per paper, were analyzed. The United States ranks first among the most productive nations in terms of total publications, accounting for 18.895%. India came in sixth place, accounting for 5.812% of total publications. The findings of the current study revealed the trend of artemia-related research studies published between 1949 and 2021. This study also highlighted the focal areas on this issue, about which future topics of research can be chosen for conservation and sustainable utilization of these vital resources.
Aeromonas
spp are the most common devastating fish bacterial pathogens associated with a wide range of cultured freshwater fish resulting in mass mortality. The present study plots the
Aeromonas
...research output in fish during 1998–2020 by means of the Web of Science (WoS) database. A total of 1944 publications were used for this investigation to evaluate the scientific productivity in this selected subject area. Global publication share, rank, and its development in terms of research and bibliometric indices such as overall citations, h-index, and average citation per paper were also analysed. China ranked first in terms of total publications among the most productive countries and accounted for 26.18% of the total publications. The network visualisation map revealed that the lead collaborating country was China; however, the collaboration between countries was found to be very less. Lokta’s law was noticed not to be valid for
Aeromonas
research. The study showed that the funding granted to the research investigations and their research productivity in terms of total publications were correlated positively. The results of the current study displayed the trend of “
Aeromonas
infection in fish” related research investigations published during 1998–2020. This study also highlighted the focused research areas on this topic on which the future areas of research can be determined by fellow researchers in this specific field. This study also suggests enhancing the research efforts on this bacterial pathogen which has the potential to implicate huge economic loss to the fish farming population in the world.
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