In the last three decades, the aquaculture sector has experienced a 527% growth, producing 82 million tons for a first sale value estimated at 250 billion USD. Infectious diseases caused by bacteria, viruses, or parasites are the major causes of mortality and economic losses in commercial aquaculture. Some pathologies, especially those of bacterial origin, can be treated with commercially available drugs, while others are poorly managed. In fact, despite having been recognized as a useful preventive measure, no effective vaccination against many economically relevant diseases exist yet, such as for viral and parasitic infections. The objective of the present review is to provide the reader with an updated perspective on the most significant and innovative vaccine research on three key aquaculture commodities. European sea bass (Dicentrarchus labrax), Nile tilapia (Oreochromis niloticus), and Atlantic salmon (Salmo salar) were chosen because of their economic relevance, geographical distinctiveness, and representativeness of different culture systems. Scientific papers about vaccines against bacterial, viral, and parasitic diseases will be objectively presented; their results critically discussed and compared; and suggestions for future directions given.

The increasing use of magnetic iron oxide nanoparticles (NPs) in biomedical applications has prompted extensive investigation of their interactions with biological systems also through animal models. A variety of toxic effects have been detected in NP-exposed fish and fish embryos, including oxidative stress and associated changes, such as lipid oxidation, apoptosis, and gene expression alterations. The main exposure route for fish is through food and the food web. This study was devised to investigate the effects of silica-coated NP administration through food in zebrafish (ZF, Danio rerio). Silica-coated magnetic NPs were administered to ZF through feed (zooplankton) from day 1 to 15 posthatching (ph). Larvae were examined 6 and 15 days ph and adults 3 and 6 months ph. A multidisciplinary approach, including morphometric examination; light, transmission electron, and confocal microscopy; inductively coupled plasma emission spectrometry; and real-time polymerase chain reaction, was applied to detect NP accumulation, structural and ultrastructural damage, and activation of detoxification processes in larvae and adults. Our findings document that the silica-coated NPs: (1) do not induce toxicity in ZF, (2) are excreted through feces, and (3) do not activate detoxification processes or promote tissue/cell injury.

Background/Aims: Probiotic strains have been recognized to exert important roles in many biological systems, including immune response, growth, development and reproduction. However, to date, no studies have focused either on the relation among probiotics and maternal factors or on probiotics' ability to qualitatively and/or quantitatively modulate maternal transcripts. Methods: In this study, the effects of Lactobacillusrhamnosus administered to parental fish on the control of maternal factors involved in autophagic, apoptotic and dorsalizing processes during zebrafish embryo development were assessed through q-PCRs, WMISH and TUNEL assay. Results: The results we obtained show that probiotic induced significant changes in both maternal and zygotic mRNA levels involved in embryo development. The maternal autophagy-regulating genes herein investigated -ambra1a, ambra1b, beclin, lc3-, as well as those involved in the apoptotic process -caspase3, bcl2, bax- were modulated in disfavor and favor of the treated group, respectively. Also, the key transcripts ruling the dorsalizing process -goosecoid and chordin- were subject to a significant regulation of their gene expression. Conclusion: The results we acquired demonstrated that parentally administered Lactobacillusrhamnosus is able to modulate important physiological processes involved in zebrafish embryo development.

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Using measurements of respiration and dissolved organic carbon (DOC) excretion from the subarctic Northeast Pacific Ocean (August 2018), we explore the efficacy of pre-existing allometric relationships to predict metabolic rates of diel vertically migrating zooplankton, and to test taxon-specific influences on these calculations at our study site. Non-taxon-specific allometric equations were associated with our best predictive model, and they underestimated measured respiratory values by ~10%. The best prediction of DOC release from estimates of biomass used taxon-specific coefficients and overestimated DOC production by 12%. There is a distinct allometric relationship for DOC excretion that varies between taxa, and slightly higher DOC production in more carnivorous groups. This study provides uncertainty estimates for zooplankton active flux analyses in the region, and identifies important research directions for allometry in biogeochemical studies.

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