Liver histopathology and biochemical biomarkers in Gobius niger and Zosterisessor ophiocephalus from polluted and non-polluted Tunisian lagoons (Southern Mediterranean Sea)

Histological biomarkers and microbiological parameters of an estuarine fish from the Brazilian Amazon coast as potential indicators of risk to human health

This study aimed to isolate and identify pathogenic bacteria in the intestinal tract, skin, and muscles of Sciades herzbergii; detect histopathological changes in the gill and liver; and use these biomarkers for the assessment of potential risks to human health. Fish were sampled during the rainy and dry seasons at two points in São Marcos Bay, Maranhão, Brazil: Ilha dos Caranguejos (IC) and Porto Grande (PG). Isolation and quantification were carried out using COLItest®. Colonies were subjected to identification and phenotypic investigation of antimicrobial resistance using Vitek®. Gill and liver samples were subjected to routine histological examination. The results indicated the presence of Klebsiella pneumoniae and Escherichia coli, the latter of which showed phenotypic resistance to norfloxacin and gentamicin. Fish caught at PG exhibited more extensive gill and liver damage than fish caught at IC. The findings suggest that histological changes in target organs of S. herzbergii may be influenced by infection with pathogenic bacteria.

Multiple biomarkers in pufferfish as a proxy of environmental health in brazilian marine protected areas

Marine Protected Areas (MPAs) are designed to conserve biodiversity and vulnerable ecosystems. This study aimed to assess the environmental quality of three Brazilian MPAs, based on the integrated analysis of biomarkers in pufferfish. The MPAs are differentiated by the degree of anthropogenic influences. The Barra do Una Estuary sustainable reserve (JUR) is a reference area due to its low levels of contamination and species diversity. The Cananéia Estuarine System (CAN) has been recognized as a biosphere reserve by UNESCO, as well as a Ramsar wetland. This MPA was influenced by upstream mining activities, resulting in the introduction of metals in the estuarine waters and the discharge of untreated urban sewage. The São Vicente estuary (SSV) lacks proper sanitation infrastructure. All collections were conducted during winter season, and, after collection, the animals were euthanized, their soft tissues were removed, and multiple biomarkers were analyzed in the gills and liver, as biometric, genotoxic, biochemical, and morphological. A one-factor multivariate analysis was applied to evaluate the differences between the data sets, and the matrices were analyzed using PERMANOVA to evaluate the "estuary" factor. The results were integrated using PCA with a 0.4 cut value and an Enhanced Integrated Biomarker Response (EIBR) was calculated. PCA was correlated with biochemical, genotoxic, and morphological biomarkers. In general, SVV differed from CAN and JUR as shown by both univariate and multivariate analyses. SVV also showed the highest EIBR, followed by CAN. Organisms from SSV showed greater gill pathology, elevated AChE activity and lipoperoxidation (LPO), and micronuclei frequency. CAN present intermediate EIBR, with severe pathologies in the liver. CAN seems to present an intermediate environmental quality between SSV and JUR indicating the importance of the existence of MPAs for environmental conservation and the need to monitor such areas, to maintain their suitable environmental quality.

Lingering Effects of Legacy Industrial Pollution on Yellow Perch of the Detroit River

We used yellow perch (Perca flavescens) captured at four sites differing in legacy industrial pollution in the Lake St. Clair-Detroit River system to evaluate the lingering sublethal effects of industrial pollution. We emphasized bioindicators of direct (toxicity) and indirect (chronic stress, impoverished food web) effects on somatic and organ-specific growth (brain, gut, liver, heart ventricle, gonad). Our results show that higher sediment levels of industrial contaminants at the most downstream Detroit River site (Trenton Channel) are associated with increased perch liver detoxification activity and liver size, reduced brain size, and reduced scale cortisol content. Trenton Channel also displayed food web disruption, where adult perch occupied lower trophic positions than forage fish. Somatic growth and relative gut size were lower in perch sampled at the reference site in Lake St. Clair (Mitchell's Bay), possibly because of increased competition for resources. Models used to determine the factors contributing to site differences in organ growth suggest that the lingering effects of industrial pollution are best explained by trophic disruption. Thus, bioindicators of fish trophic ecology may prove advantageous to assess the health of aquatic ecosystems. Environ Toxicol Chem 2023;42:2158-2170. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Univariate or multivariate approaches for histopathological biomarkers in the context of environmental quality assessments?

Although the simplification of multivariate histopathological data into univariate indices can be useful for the assessment of environmental quality, this implies a great loss of information. The objective of the present study was to evaluate the effectiveness, in the context of environmental quality assessment, of an approach that integrates individual histopathological responses in a discriminated manner with the results of contaminants by means of multivariate analyses. This analysis was compared to the diagnosis of environmental quality provided by the use of the univariate Bernet histopathological index. Contaminant loads (sediments and fish) and the liver histopathology of Cathorops spixii were integrated through multivariate analysis. Integrated individual histopathological responses allowed classifying environmental quality from more to less impacted sites, while the univariate index showed some inconsistencies with chemical loads and allowed identifying only the most impacted site.

Mechanistic revealing of reproductive behavior impairment in male guppy (Poecilia reticulata) induced by environmentally realistic 2,2'-dithiobis-pyridine exposure

Although (PS)₂, the primary degradation product of emerging antifouling biocides metal pyrithiones (MePTs), can disrupt the reproductive behavior of fish at an environmentally relevant ng/L level, the underlying mechanism is still largely unknown. This study exposed sexually mature male guppy (Poecilia reticulata) to 20, 200, and 2000 ng/L (PS)₂ to explore the compromised effect of (PS)₂ on reproductive behavior through a realistic competing scenario. The results showed that (PS)₂ suppressed male guppies' sexual interest to stimulus females, reduced their competitive behavior frequencies toward rival males, and decreased their mating time and frequency. (PS)₂ exposure did not affect male guppies' secondary sexual characteristics or induce estrogenic activity. Whole-brain transcriptome sequencing identified 1070 differentially expressed genes (DEGs) with 872 up-regulated genes, which were functionally enriched into Gene Ontology terms pertaining to extracellular matrix (ECM) and extracellular region. KEGG enrichment for the DEGs uncovered that the activations of ECM-receptor interaction and focal adhesion pathways could be the underlying molecular mechanism implicated in the (PS)₂ induced reproductive behavior impairment. This work would deliver a substantial contribution to the understanding of the ecological safety of MePTs biocides.

Bioaccumulation of polycyclic aromatic hydrocarbons in Solea solea from Bizerte and Ghar El Melh Lagoons (Tunisia) and human health risk assessment

The present study objective was to assess polycyclic aromatic hydrocarbons in Bizerte and Ghar El Melh Lagoons Solea solea and to assess the potential risk to human health from its consumption. To reach these objectives twenty fish samples from each site were collected and 15 priority polycyclic aromatic hydrocarbons (PAHs) were analyzed in their muscles using high-performance liquid chromatography with a fluorescence detector. Total PAH sole concentrations from Bizerte and Ghar El Melh Lagoons were similar or lower to those recorded in other species from other regions across the world. In the studied fish species, the 2 and 3 ring PAHs are the dominated compounds that enter to the composition of PAHs which indicates that PAHs could be principally derived from a petrogenic origin for the both studied lagoons. The human health risk by sole consumption was evaluated and revealed to exhibit no hazard to the local population health concerning PAH intakes. The findings of this biomonitoring study will help in the implementation of sustainable environmental policies for effective water pollution control and the two investigated lagoons management.

Whole-genome sequencing reveals sex determination and liver high-fat storage mechanisms of yellowstripe goby (Mugilogobius chulae)

As a promising novel marine fish model for future research on marine ecotoxicology as well as an animal model of human disease, the genome information of yellowstripe goby (Mugilogobius chulae) remains unknown. Here we report the first annotated chromosome-level reference genome assembly for yellowstripe goby. A 20.67-cM sex determination region was discovered on chromosome 5 and seven potential sex-determining genes were identified. Based on combined genome and transcriptome data, we identified three key lipid metabolic pathways for high-fat accumulation in the liver of yellowstripe goby. The changes in the expression patterns of MGLL and CPT1 at different development stage of the liver, and the expansion of the ABCA1 gene, innate immune gene TLR23, and TRIM family genes may help in balancing high-fat storage in hepatocytes and steatohepatitis. These results may provide insights into understanding the molecular mechanisms of sex determination and high-fat storage in the liver of marine fishes.

Antioxidant system status in threatened native fish Barbus meridionalis from the Osor River (Iberian Peninsula): I. Characterization and II. In vitro Zn assays

The evaluation of antioxidant system capacity is important in aquatic toxicology. It was aimed to characterize the liver antioxidant enzymes (SOD, CAT, GPX, GR, and GST) and to test the in vitro Zn effect (200 and 400 ZnSO₄ μg/L) in native fish Barbus meridionalis obtained from the Osor River (NE, Spain) influenced by Zn contamination. The maximal enzyme activities were at pH 7.0-7.5 and 100 mM phosphate buffer. Barbel showed high catalytic activity (high Vmax and low Km) indicating the efficient antioxidant detoxification ability. Direct Zn effect caused an antioxidant system imbalance. Mostly upon lower Zn concentration, GPX activity decreased (95-100 %) though CAT, GR, and GST increased (36-1543 %). GSH values either stimulated (290 %) or inhibited (85-93 %) due to tissue differences. The first record of barbel antioxidant enzyme characterization and in vitro data presenting an unbalanced antioxidant pattern could be significant to evaluate the metal pollution in the Osor River for further in vivo studies.

Metal body burden and tissue oxidative status in the bivalve Venerupis decussata from Tunisian coastal lagoons

Coastal transitional waters are exposed to many anthropogenic threats. This study aims to assess the trace metals' pollution status of transitional waters by evaluating its biological effects in the clam Venerupis decussata. Among the studied sites along the Tunisian littoral, South Tunis and Boughrara were the most impacted, since clams from these two lagoons presented significant differences in: (i) trace metal contents, (ii) in-cell hydrogen peroxide, (iii) enzymatic and non-enzymatic defenses, (iv) damage to lipids and proteins, and (v) protein post-translational modifications. These changes related to evident histopathological traits. PCA showed a clear separation between the digestive gland and gills tissues and illustrated an impact gradient in Tunisian coastal lagoons. Water temperature was revealed as an added natural stressor that, when concurring with high pollution, may jeopardize an ecosystem's health and contribute to the accumulation of hazardous metals in organisms.

Growth, serum biochemical, and histopathological responses of broilers administered with silver nanoparticles as a drinking water disinfectant

The supplementation of 50 ppm dosed silver nanoparticles (AgNPs) as a disinfectant in broilers drinking water was investigated to examine their growth performance, blood serum biochemistry, and organ histology in the case group, compared to the control. The growth performance parameters, such as water intake, feed intake, and body weight were recorded 6 times, each in an interval of 7 days, over a period of 42 days. At the end of each 42 days, the blood and major organs of the 1 case boiler out of 75 and 1 control broiler out of 75 were collected in random. The procedure was repeated 3 sets one after another, each consisting 42 day intervening period. The liver enzyme, lipid profile, glucose level, organ histology, and concentration of AgNPs in liver, spleen, heart, and small intestine were determined. The obtained results show that the growth performance of the case broilers was significantly higher than the control section (p < 0.05). However, in all the three sets the changes in lipid profile, liver enzyme, and glucose level of the case broilers were not statistically significantly different compared to the control (p > 0.05). The histology of liver, kidney, heart, spleen, and small intestine of broilers has not shown any damages to the cells as compared to the control samples. In the case samples, the highest concentration of AgNPs was observed in the small intestine (5.44 µg/g) followed by liver (4.32 µg/g), kidney (3.94 µg/g), heart (3.82 µg/g), and spleen (3.49 µg/g). The present study concludes that the administering 50 ppm AgNPs of average 15 nm size in the poultry drinking water was found safe for consumption as well as for growth enhancing, due to better bird comfort.

Assessment of the biochemical and nutritional values of Venerupis decussata from Tunisian lagoons submitted to different anthropogenic ranks

The present study aimed to evaluate the biochemical status of Venerupis decussata collected seasonally from two Tunisian coastline lagoons (Ghar El Melh and Boughrara) submitted to different anthropogenic levels. Trace elements were significantly higher in clams from Boughrara, especially during the warm season. Fatty acids, proximate compositions, and nutritional value of both clam populations were higher, appearing to be the best for human consumption principally during the spring season. The principal component analysis was determined, including phospholipids and reserve lipids, revealing a great variation with the exogenous and endogenous factors. Generally, clams from Boughrara had a significant alteration in biochemical composition principally due to the anthropogenic levels and physicochemical fluctuation of this lagoon. Our results reflected the healthy benefit of clam consumption and the use of energy reserves and essential fatty acids as a great biomarker to assess ecological risk in lagoons and other coastal ecosystems.