Kvalitet jaja morskih riba u akvakulturi, pregled tehnika i rezultata

Background: Despite most of marine teleosts can produce large quantities of viable eggs in captivity, the quantity and quality of the larvae are low and variable, being the initial quality of the eggs one of the main causes of the variability. Considering that commercial hatcheries rely on good larval quality, the establishment of a series of criteria for egg quality is of paramount importance. Objectives: This review presents an overview on some of recent researches carried out in IRTA and University of Salzburg (2004‒2010) to address this bottleneck through correlating egg biochemical contents (BC) to embryo/larva success in a marine teleost considered as new species for Mediterranean aquaculture. Target species: Besides production cost reduction and market enlargement, species diversification is one of the main strategies to ensure future expansion of aquaculture industry. A series of biological and commercial characteristics make the common dentex, Dentex dentex, a highly suitable species to enter mariculture systems as a new species to supplement the intensive sparids production and to increase diversification. Applied methodologies: (i) Viable eggs were obtained from natural spawning of broodfish in captivity. (ii) Egg biometrical parameters (i.e., wet mass, dry mass, and water content) were recorded. (iii) Embryo/larva viability parameters (VPs, i.e., floating rate, hatching rate, and survival rate) were determined. (iv) Egg biochemical parameters (i.e., carbohydrate metabolites/enzymes, vitellogenin-derived proteins [VDP], non-Vtg-derived protein [non-VDP], free amino acid [FAA], proteinic amino acids [PAA], lipid classes [LC], fatty acids [FA], and morphological characteristics of lipid vesicle [LV]) were characterized and quantified. (v) A variety of statistical analyses were used to define the relationships existing between the egg BCs (as egg quality indicators) and the VPs (as criteria for embryo/larva success) that are currently used in mariculture systems. Results: Although a combination of statistical methods were used to correlate the egg BCs to embryo/larva success in common dentex, the current review was prepared based on the results of regression models. Carbohydrate (CH) metabolite contents and enzyme activity of the egg together with VDP, non-VDP, FAA, PAA, LC , and FA contents for one side and lipid vesicle (LV) morphological characteristics on the other were significantly and strongly correlated to embryo/larva success through almost 350 simple regression model (11 [r2=0.184‒0.490] for CHs and enzymes, 16 [r2=0.095‒0.634] for VDPs, 55 [r2=0.079–0.637] for non-VDPs, 49 [r2=0.605–0.875] for FAAs, 19 [r2=0.919−0.991] for PAAs, 5 [r2=0.459–0.739] for LCs, 201 [r2=0.640–0.948] for FAs, and 10 [r2=0.293–0.480] for LV). Conclusions: (i) Under a biological/physiological perspective the significant relationships found between egg BCs and embryo/larva success in common dentex highlight the importance of egg composition during the initial events of embryonic/larval development. The results obtained present a series of new relationships (either in agreement or against previous findings) that deserve further investigation to define their physiological ground. (ii) Under a more applied perspective these relationships indicate a potential use of egg BCs, as bio-markers, to predict egg quality in aquaculture. These markers can also be used as molecular probes to assess the improvements in broodstock management

Imatinib Mesylate Effects on Zebrafish Reproductive Success: Gonadal Development, Gamete Quality, Fertility, Embryo-Larvae Viability and Development, and Related Genes

Imatinib (IM) is a tyrosine kinase (TK) inhibitor (TKI) used to treat chronic myeloid leukemia. Clinical case reports and a few laboratory mammal studies provide inconclusive evidence about its deleterious effects on reproduction. The aim of the current study was to evaluate the potential of zebrafish to characterize IM-induced effects on reproduction and clarify IM effects on reproductive success. To this end, we exposed adult zebrafish to four concentrations of IM for 30 days followed by a 30-day depuration period. IM exposure caused a concentration-dependent, irreversible, suppression of folliculogenesis, reversible decrease in sperm density and motility, decreased fecundity and fertility, but no significant change in atretic follicle abundance. We also observed IM-induced premature hatching, but no significant change in embryo-larvae survivability. However, we found significant IM-induced morphometric malformations. IM decreased expression of vegfaa and igf2a (two reproductive-, angiogenic-, and growth-related genes) in testes and ovaries. The results demonstrate IM can induce significant changes in critical reproductive endpoints and zebrafish as a suitable model organism to show effects of IM on reproduction. The findings suggest that TKI effects on reproductive success should be considered

Morphometric Characteristics and Time to Hatch as Efficacious Indicators for Potential Nanotoxicity Assay in Zebrafish

Although the effects of nano-sized titania (nTiO2) on hatching events (change in hatching time and total hatching) in zebrafish have been reported, additional consequences of nTiO2 exposure (i.e., the effects of nTiO2-induced changes in hatching events and morphometric parameters on embryo-larvae development and survivability) have not been reported. To address this knowledge gap, embryos 4 h postfertilization were exposed to nTiO2 (0, 0.01, 10, and 1000 μg/mL) for 220 h. Hatching rate (58, 82, and 106 h postexposure [hpe]), survival rate (8 times from 34 to 202 hpe), and 21 morphometric characteristics (8 times from 34 to 202 hpe) were recorded. Total hatching (rate at 106 hpe) was significantly and positively correlated to survival rate, but there was no direct association between nTiO2-induced change in hatching time (hatching rate at 58 and 82 hpe) and survival rate. At 58, 82, and 106 hpe, morphometric characteristics were significantly correlated to hatching rate, suggesting that the nTiO2-induced change in hatching time can affect larval development. The morphometric characteristics that were associated with change in hatching time were also significantly correlated to survival rate, suggesting an indirect significant influence of the nTiO2-induced change in hatching time on survivability. These results show a significant influence of nTiO2-induced change in hatching events on zebrafish embryo-larvae development and survivability. They also show that morphometric maldevelopments can predict later-in-life consequences (survivability) of an embryonic exposure to nTiO2. This suggests that zebrafish can be sensitive biological predictors of nTiO2 acute toxicity

Zebrafish as a Model to Screen the Potential of Fatty Acids in Reproduction

Sperm quality is an important topic in general health, chemotherapy, and gamete preservation technology. Fatty acid (FA) composition of membranes, which is influenced by the diet, plays key roles in sperm biology and quality. Dietary supplementation with natural products can be used as a technique to screen potential agents to protect, modify, and recover sperm quality. In this study, zebrafish (male [♂-ZF] and female [♀-ZF]) were fed a single cultivar olive oil (OO) bioencapsulated in Artemia. OO-treated ♂-ZF had higher (p < 0.05) sperm density and motility compared to the Artemia nauplii (AN). A significant difference was also observed in follicle abundance at different stages of gametogenesis, and a nonsignificant increase in total fecundity between OO-treated ♀-ZF and the AN, although in OO-treated ♀-ZF, mature follicles had a smaller diameter. A higher fertility rate (FR) was observed in OO-treated pairs compared to the other groups. Hatching in the OO-treated fish was accelerated, although no significant differences could be found in terms of hatching rate (HR) and embryo/larval survival rate (SR). These findings in FR, HR, and SR were also confirmed in male and female replacement mating trials. Taken together, this study shows that altering the FA ratios in the diet has a clear impact on several reproductive parameters in the zebrafish, adding new information about the nutritional requirement of this model species.info:eu-repo/semantics/acceptedVersio

Laser Irradiation as a Novel Alternative to Detach Intact Particulate Matter Collected on Air Filters

Airborne particulate matter (PM) is collected on specific filters. For subsequent testing, the PM should be detached intact from the filter. Liquid extraction (LE), the standard method to detach PM from air filter surfaces, is challenging and can be tedious. Laser irradiation has been used to characterize PM on filters, but not to detach PM from filters for subsequent testing. A feasibility study was conducted to assess the potential of laser irradiation to detach PM from air filters. Laser-detached PM was deposited on a pre-weighed glass plate. PM detachment and collection were conducted in a single step. PM-coated air filters were subjected to visual inspection, gravimetric assessment of captured PM, and spectroscopic scanning (ATR-FTIR, SEM-EDS, and XRD) before and after laser irradiation. Laser irradiation PM detachment efficiency was up to 78 %. Functional groups, elements, and minerals of PM collected on filter surfaces disappeared or significantly decreased after irradiation, demonstrating detachment, without suffering a change in their nature. No evidence of filter fragments was found in the detached PM. Laser irradiation was i) an easy, ii) rapid, and iii) single step procedure that iv) detached PM, v) didn\u27t detach filter fragments, vi) didn\u27t change PM composition, and vii) is amenable to automation and high throughput. Laser irradiation to detach PM from air filters as an alternative to LE is worthy of further study and development

An Endeavor to Find Starter Feed Alternatives and Techniques for Zebrafish First-Feeding Larvae: The Effects on Viability, Morphometric Traits, Digestive Enzymes, and Expression of Growth-Related Genes

Low and variable growth and survival rates (SR) of 6–10 days postfertilization zebrafish larvae are a problem. This problem seems to be linked to starter feed characteristics. This study is an attempt to find alternatives to address these requests. For this, larvae were fed fresh and lyophilized microalgae (Chlorella, Scenedesmus, and Haematococcus), egg yolk (YOLK), lyophilized Artemia nauplii (LAN), and a combination of them. The lowest SR was observed in algae-fed larvae. All died on day 11 showing an emaciated appearance, similar to starved larvae. The highest SR was observed in YOLK- and LAN-fed larvae, which also showed an elongated anterior part of the body. Negative correlations of SR with vegfaa (vascular endothelial growth factor) and morphometric traits with igf2a (insulin-like growth factor) were also found and supported by changes at the molecular level. The presence of algae in the digestive tract of the larvae and the observation of fecal droppings indicate that the algae have an appropriate size and are palatable. The increase in the digestive enzyme activity shows the larval effort to digest the algae. The fact that the algae-fed larvae died even before the larvae were kept in starvation indicates the dramatic amount of energy that the larvae spent in microalgae digestion. Although both YOLK- and LAN-fed larvae had the highest SR, LAN group started to feed on Artemia nauplii sooner. This can be linked to the delayed growth in YOLK-fed larvae and an accelerated growth in the case of LAN-fed group. LAN is an expensive feed with negative effects on water quality, whereas YOLK is a cheap and nutritionally balanced feed with fine granular texture that contributes to a larval SR similar to LAN without affecting water quality. In conclusion, microalgae cannot be considered a suitable starter food for zebrafish, whereas LAN and YOLK can be considered good starter feeds.info:eu-repo/semantics/acceptedVersio