Effect of Microplastics on the Accumulation of POPs in Fish

Microplastic are ubiquitous in aquatic habitats and commonly found in the gut contents of fish yet relatively little is known about the retention of microplastic particles by fish. Microplastics also contribute to an anthropogenic organic phase in the environment capable of absorbing hydrophobic organic compounds including persistent organic pollutants (POPs). Relatively little is known about the potential interactions between microplastics and persistent organic pollutant (POP) exposures to fish. In order to determine how microplastic particles affect the accumulation of POPs in fish, I first determined the gut retention of two types of microplastic particles (microbeads and microfibers) in goldfish. Although a small number of microplastic particles were retained in fish GI-tracts after 6 days (0-3 particles/50), the retention of microplastics was generally similar to the retention of bulk digesta contents. According to a breakpoint regression model fitted to digesta contents and microplastic particles, the 50% and 90% evacuation times were 10 h and 33.4 h, respectively. The results of this study indicate that neither microbeads nor microfibers are likely to accumulate within the gut contents of fish over successive meals. In Chapter 3 of this thesis, I applied a duel-tracer design to quantify polychlorinated biphenyl (PCB) dietary assimilation efficiencies (AE) in goldfish to compare microplastic-associated PCB AEs with diet matrix-associated PCB AEs. Microplastic-associated PCBs showed a 13.36% (12.27-14.49%) assimilation efficiency in goldfish while food matrix-associated PCBs showed 51.64% (48.97-54.32%) assimilation efficiency; which is 3.9 fold higher than measured for microplastic-associated PCBs. The joint findings from this thesis indicate that microplastic particles, and POPs associated with them, are unlikely to significantly enhance POPs bioaccumulation by fish

Volatile compounds of some popular Mediterranean seafood species

The volatile compounds of highly commercialised fresh Mediterranean seafood species, including seven fish (sand-smelt Atherina boyeri, picarel Spicara smaris, hake Merluccius merluccius, pilchard Sardina pilchardus, bogue Boobps boops, anchovy Engraulis encrasicolus and striped-mullet Mullus barbatus), squid (Loligo vulgaris), shrimp (Parapenaeus longirostris) and mussel (Mytilus galloprovincialis), were evaluated by simultaneous steam distillation-extraction and subsequent GC-MS analysis. A total of 298 volatile compounds were detected. The mussels contained the highest total concentration of volatile compounds, while pilchard among fish species contained the highest number and concentrations of volatile compounds. Individual patterns of volatile compounds have been distinguished. The fish species when compared to the shellfish species studied, contained 6 to 30 times more 1-penten-3-ol, higher quantities of 2-ethylfuran, and 2,3-pentanedione, which was absent from the shellfish species. Pilchard is characterized by a high concentration of alcohols, shrimps by the high presence of amines and S-compounds, while mussels by high amounts of aldehydes, furans, and N-containing compounds (pyridine, pyrazines and pyrrols). The fatty acid-originating carbonyl compounds in fish seem to be related to the species’ fat content

Determination of the gut retention of plastic microbeads and microfibers in goldfish 1 (Carassius auratus)

Microplastics are ubiquitous pollutants in aquatic habitats and commonly found in the gut contents of fish yet relatively little is known about the retention of these particles by fish. In this study, goldfish were fed a commercial fish food pellet amended with 50 particles of one of two microplastics types, microbeads and microfibers. Microbeads were obtained from a commercial facial cleanser while microfibers were obtained from washed synthetic textile. Following consumption of the amended pellet, fish were allowed to feed to satiation on non-amended food followed by fasting for periods ranging from 1.5 h to 6 days. Fish sacrificed at different time points were dissected to remove gut contents and the digesta contents retention and microplastic retention was determined. Although a small number of microplastic particles were retained in fish GI-tracts after 6 days (0–3 particles/50), the retention of microplastics was generally similar to the retention of bulk digesta contents. According to a breakpoint regression model fitted to digesta contents and microplastic particles, the 50% and 90% evacuation times were 10 h and 33.4 h, respectively. The results of this study indicate that neither microbeads nor microfibers are likely to accumulate within the gut contents of fish over successive meals

Polyphenolic burden and in vitro antioxidant properties of Moringa oleifera root extracts

ntroduction: Moringa oleifera is a small tree with very significant nutritional but alsopharmacological properties and various preparations from almost all parts of the plant (leaves,fruit, stems, bark, roots) are used in folk medicine for treating several ailments. This study aimedto investigating the polyphenolic burden and in vitro antioxidant properties of M. oleifera rootextracts, obtained with solvents covering a range of polarities.Methods: Lyophilised Moringa oleifera roots were extracted with solvents of increasing polarity,including ethyl acetate, butanol, methanol and water. The generated extracts were screened forpolyphenolic load and antioxidant activities, by determining the total polyphenol, total f lavonoid,total f lavanol, antiradical activity and reducing power. Liquid chromatography-mass spectrometrywas also employed to obtain some evidence regarding the nature of the main constituents.Results: The results indicated that both aqueous and methanolic extracts were the richestin total polyphenols, but the aqueous extract also exhibited high reducing power. The liquidchromatography-diode array-mass spectrometry analysis also revealed that the major substancesoccurring in the aqueous extract were relatively polar molecules, but the mass spectral data wereambiguous to assign tentative structures.Conclusion: Polar solvents, such as water, may be effectively used to recover high amounts of M.oleifera root phenolics, which possess important antioxidant properties.&nbsp

Season and size effects: changes in the quality of gilthead sea bream (Sparus aurata L.)

The aim of this study was to investigate the potential effects of the harvesting season and fish size on the final quality of cage farmed gilthead sea bream (Sparus aurata). Morphometric analysis, fat stores estimation, fillet composition analysis, fillet fatty acids profile determination and sensory analysis were carried out on a commercially-sized cage farmed gilthead sea bream (Sparus aurata L.) population in April, June, July and November. Both season and size had a significant effect in morphometric characteristics. The most pronounced size effect was the change of fish shape, becoming rounder with fish growth, the increase of filleting yield and condition index. An increase of both peritoneal and perivisceral fat was observed in summer months. In general size had little effect on muscle composition. A significant size effect was observed in the fillet lipid content, which increased with it. Fillet lipid content was unexpected lower in the warm period (June-July). This can be possibly attributed to feeding restrictions that may have occurred, due to anoxic incidents related to high temperatures.Slight seasonal differentiations occurred in the muscle fatty acids. No significant differences were found in the organoleptic characteristics of the two size groups compared

Nondestructive Semistatic Testing Methodology for Assessing Fish Textural Characteristics via Closed-Form Mathematical Expressions

This paper presents a novel methodology based on semistatic nondestructive testing of fish for the analytical computation of its textural characteristics via closed-form mathematical expressions. The novelty is that, unlike alternatives, explicit values for both stiffness and viscoelastic textural attributes may be computed, even if fish of different size/weight are tested. Furthermore, the testing procedure may be adapted to the specifications (sampling rate and accuracy) of the available equipment. The experimental testing involves a fish placed on the pan of a digital weigh scale, which is subsequently tested with a ramp-like load profile in a custom-made installation. The ramp slope is (to some extent) adjustable according to the specification (sampling rate and accuracy) of the equipment. The scale’s reaction to fish loading, namely, the reactive force, is collected throughout time and is shown to depend on the fish textural attributes according to a closed-form mathematical formula. The latter is subsequently used along with collected data in order to compute these attributes rapidly and effectively. Four whole raw sea bass (Dicentrarchus labrax) of various sizes and textures were tested. Changes in texture, related to different viscoelastic characteristics among the four fish, were correctly detected and quantified using the proposed methodology

Small cell carcinoma of the urinary tract: a case report

Neuroendocrine small cell carcinoma of the urinary tract is rarely encountered and very few cases have been reported in the literature. Herein we describe a case of small cell malignancy located contemporarily in the ureter and the bladder

Uticaj različitih termalnih uslova na hemijski sastav mesa kalifornijske pastrmke sa dve farme u severozapadnoj Grčkoj

Rainbow trout from two fish farms were reared under different thermal regimes, Farm Awas located by a river in a mountain region of Epirus and farm B was located in a lowland location at the coast of Preveza. Lower temperature prevailed in farm A (10-11 oC vs. 16-16,6 in farm B). Proximate composition analysis indicated that the different thermal conditions resulted in significant differences in the filleting yield and the proximate composition of rainbow trout axial musculature. The fish from the farm B exhibited higher growth rate and fillet lipid contents. This research has been co-financed by the European Union (European Social Fund – ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: ARCHIMEDES III. Investing in knowledge society through the European Social Fund.Kalifornijske pastrmke su gajene u različitim termalnim režimima. Jedna farma (A) se nalazila pored reke u planinskom regionu Epira, a druga (B) se nalazila u nizijskom delu, na obalskom delu Preveza. Na farmi A su preovlađivale niže temperature (10-11 oC prema 16-16.6 na farmi B). Analiza hemijskog sastava ukazuje da su različiti temperaturni režimi doveli do značajnih razlika u kvalitetu fileta I cele aksijalne muskulature. Ruba sa farme B je imala veću stopu rasta I sadržaj lipida u filetima. Ovo istraživanje je ko finansirano od strane Evropske Unije (Evropski socijalni fond, European Social Fund – ESF) i Grčkih nacionalnih fondova kroz Operativni program «Obrazovanja i celoživotno učenje - Education and Lifelong Learning «Nacionalnog Strateškog referentnog okvira (NSRF) – Program finansiranja istraživanja ARCHIMEDES III – Investiranje u društvo znanja kroz Evropski socijalni fond

Sustainability vs. Quality in gilthead seabream (Sparusaurata L.) farming: are trade-offs inevitable?

European aquaculture industry should be at the forefront of sustainable development, providing healthy and safe food of the highest quality to the consumer, through an environmentally sound approach. The purpose of this review was to explore in what way the current drive for sustainability has affected what the consumer perceives as quality in fish, specifically in gilthead seabream, one of the most important farmed species in the Mediterranean. It focuses on nutritional aspects such as fish meal and fish oil replacement, quality tailoring through finishing strategies, the influence of different farming systems and the effect of slaughter stress on seabream quality. In general, fish meal and fish oil replacement with vegetable ingredients will result in changes in the fatty acid profile of the fillets, and consequently the potential health benefits seabream offers to the consumer. While organoleptic properties suffer little change, the impact of these ingredients on welfare has not been fully investigated. Further studies are also needed to evaluate the effect of land animal ingredients on seabream quality. In either case, although finishing strategies to restore essential fatty acids are not completely effective, seabream can still retain a high nutritional value. Information on the use of dietary supplements as finishing strategies is still extremely scarce. Regarding fish welfare, the high densities practised in intensive production systems pose concerns which warrant further research in this area. Furthermore, new alternatives for common harvesting and slaughter methods are needed to improve welfare, as traditional methods are clearly stressful.FCT, Portugal [SFRH/BD/40886/2007, SFRH/BD/41392/2007]info:eu-repo/semantics/publishedVersio