Effect of acute exposure to settleable atmospheric particulate matter emitted by the steel industry on hematology and innate immunity of fat snook (Centropomus parallelus).

The steel industry is a significant worldwide source of atmospheric particulate matter (PM). Part of PM may settle (SePM) and deposit metal/metalloid and metallic nanoparticles in aquatic ecosystems. However, such an air-to-water cross-contamination is not observed by most monitoring agencies. The region of Vitoria City is the main location of iron processing for exports in Brazil, and it has rivers, estuaries, and coastal areas affected by SePM. We have evaluated the effects of SePM on a local representative fish species, the fat snook, Centropomus parallelus. After acclimation, 48 fishes (61.67 ± 27.83 g) were individually exposed for 96 h to diverse levels of SePM (0.0, 0.01, 0.1 and 1 g/L-1). The presence of metals in the blood and several blood biomarkers were analyzed to evaluate the impact of SePM on stress signaling, blood oxygen transport capacity, and innate immune activity. Metal bioaccumulation was measured from blood in two separately analyzed compartments: intracellular (erythrocytes plus white blood cells) and extracellular (plasma). The major metals present at all contamination levels in both compartments were Fe and Zn, followed by Al and Cu, plus traces of 'Emerging metals': Ba, Ce, La, Rb, Se, Sr, and Ti. Emerging metals refer to those that have recently been identified in water as contaminants, encompassing rare earth elements and critical technology elements, as documented in previous studies (See REEs and TCEs in Cobelo-García et al., 2015; Batley et al., 2022). Multivariate analysis revealed that SePM had strong, dose-dependent correlations with all biomarker groups and indicated that blood oxygen-carrying capacity had the highest contamination responsiveness. Metal contamination also increased cortisol and blood glucose levels, attesting to increased stress signaling, and had a negative effect on innate immune activity. Knowledge of the risks related to SePM contamination remains rudimentary. However, the fact that there was metal bioaccumulation, causing impairment of fundamental physiological and cellular processes in this ecologically relevant fish species, consumed by the local human population, highlights the pressing need for further monitoring and eventual control of SePM contamination.

Metalliferous atmospheric settleable particulate matter action on the fat snook fish (Centropomus parallelus): Metal bioaccumulation, antioxidant responses and histological changes in gills, hepatopancreas and kidneys.

Metallic smoke released by steel industries is constitute by a mixture of fine and gross particles containing metals, including the emerging ones, which sedimentation contaminates soil and aquatic ecosystems and put in risk the resident biota. This study determined the metal/metalloids in the atmospheric settleable particulate matter (SePM, particles >10 µm) from a metallurgical industrial area and evaluated metal bioconcentration, antioxidant responses, oxidative stress, and the histopathology in the gills, hepatopancreas and kidneys of fat snook fish (Centropomus parallelus) exposed to different concentrations of SePM (0.0, 0.01, 0.1 and 1.0 g L-1), for 96 h. From the 27 metals (Al, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Y, Zr, Nb, Mo, Ag, Cd, Sn, Ba, La, Ce, W, Hg, Pb, Bi) analyzed, 18 were quantified in SePM and dissolved in seawater. Metal bioconcentrations differed among organs; Fe and Zn were the metals most bioconcentrated in all organs, Fe was higher in hepatopancreas and Zn > Fe > Sr > Al was higher in kidneys. The activity of superoxide dismutase (SOD) decreased in the gills; SOD, catalase (CAT) decreased, and glutathione peroxidase (GPx) increased in hepatopancreas and, CAT, glutathione-S-transferase (GST) and the level of glutathione (GSH) increased in kidneys. The unchanged levels of lipid peroxidation and oxidized protein in any organ indicate that the antioxidant responses were efficient to avoid oxidative stress. Organ lesion indices were higher in the gills > kidneys > hepatopancreas, being higher in fish exposed to 0.01 g L-1 SePM. All changes indicate a tissue-specific metal/metalloids bioconcentration, antioxidant and morphological responses that all together compromise fish health. Regulatory normative are needed to control the emission of these metalliferous PM to preserve the environment and biota.

Settleable atmospheric particulate matter induces stress and affects the oxygen-carrying capacity and innate immunity in Nile tilapia (Oreochromis niloticus).

Steel industry emissions of atmospheric particulate matter are responsible for air to water cross-contamination, which deposits metal/metalloid contaminants in aquatic ecosystems. This source of contamination has not been considered in most of the environmental monitoring protocols. Settleable atmospheric particulate matter (SePM) collected in an area of steel industry influence was used to analyze the sublethal effects on the hematological and innate immunological variables in Nile tilapia (Oreochromis niloticus) after short-term exposure (96 h). Blood samples were analyzed to evaluate the oxygen-carrying transport capacity, innate immune activity and stress biomarkers after exposure to ecologically relevant concentration of SePM. The exposure reduced blood oxygen-carrying capacity by lessening hematocrit, hemoglobin, erythrocyte, and mean corpuscular hemoglobin concentration. Compensatory increments in mean corpuscular volume and mean corpuscular hemoglobin have also been observed. The contaminant impacted the immune system by reducing the number of leukocytes, thrombocytes, and monocytes, total plasma protein, leukocyte respiratory activity, and by increasing lysozyme concentration. Furthermore, the contaminant caused endocrine stress response, raising plasma cortisol and glucose. Therefore, the alterations caused by SePM threatened the capacity of sustaining aerobic metabolism, impaired the immune system, and changed the energy allocation due to both stress response and immune effect. This may have important implications for the impact of SePM on aquatic ecosystems. Future investigations should assess SePM impact on general physiology and aerobic performance, especially to face common ecological challenges such as hypoxia and sustained swimming. These results point out the need to develop proper protocols to address the air-to-water cross-contamination risks by iron ore processing industries.

Bioconcentration and toxicological impacts of fipronil and 2,4-D commercial formulations (single and in mixture) in the tropical fish, Danio rerio.

The insecticide fipronil and the herbicide 2,4-D are the most applied pesticides in sugarcane crops leading to aquatic contamination. The whole-body bioconcentration of fipronil and 2,4-D, single and in mixture, was evaluated in Danio rerio after 96-h exposure. The activities of catalase (CAT) and glutathione S-transferase(GST) in whole body and in the gills and the acetylcholinesterase (AChE) in muscle were determined. The gill histopathology and the morphology of the pavement (PVC) and the mitochondria-rich(MRC) cells at gill surface were analyzed. Bioconcentration occurred after exposure to fipronil (2.69 L kg-1) and 2,4-D (1.73 L kg-1) single and in mixture of fipronil (3.10 L kg-1) and 2,4-D (1.27 L kg-1). Whole-body CAT activity was unchanged, and its activity decreased in the gills after exposure to fipronil and increased after exposure to 2,4-D and mixture. GST and AChE increased after single exposure to each pesticide and mixture of both. Fish exposed to mixture increased the MRC fractional area (MRCFA) which suggested possible ionic regulation disturbance and reduced the microridge of the PVC surface. Synergistic interactions occurred in the CAT activity and MRCFA after exposure to mixture of pesticides. The results indicate that the recommended application dose of fipronil and 2,4-D, single or in mixture, for sugarcane crops affects this fish species altering its homeostasis.

Phytobiotics blend as a dietary supplement for Nile tilapia health improvement.

Functional additives of natural origin included as dietary supplements have become an alternative to synthetic antibiotics to improve health and resistance to ecologically correct pathogenic diseases in fish farming. We tested whether incorporating a mixture of phytobiotics such as volatile oils of thyme, red thyme and pepper rosemary into the diet improves growth performance, oxidative stress, immune and hematological responses and resistance of juvenile Nile tilapia when subjected to a challenge with Aeromonas hydrophila compared to a synthetic antibiotic (enrofloxacin). The experimental design was completely randomized with three experimental groups: control diet, diets containing a mixture of thyme phytobiotic essential oils, red thyme and pepper rosemary (FTB) and the synthetic antibiotic enrofloxacin (ATB), with four replicates (14 fish per repetition/experimental unit). Plasma glucose levels, leukocyte respiratory activity, serum lysozyme levels, number of circulating erythrocytes and leukocytes, levels of lipid peroxidation (LPO), catalase (CAT) and glutathione S-transferase (GST) activity at the end of 20 days of feeding (phase) were evaluated and 24 h after exposure to bacteria (phase II). The supplementation of FTB and ATB did not change the performance parameters, but it was sufficient to increase lysozyme, leukocytes, neutrophils and monocytes after the bacterial challenge, reduction of CAT and LPO activity and the highest GST activity (P < 0.05). The results of the present study suggest that FTB as a dietary supplement has benefits and can replace synthetic ATB, including supplementation with FTB for 20 days to provide greater antioxidant protection in Nile tilapia, mitigate the impacts of stressors and modulate immunity, providing to fish greater resistance and protection against diseases.

Evaluation of health and environmental risks for juvenile tilapia (Oreochromis niloticus) exposed to florfenicol.

Intensive fish cultivation has a high incidence of infection, which is often controlled by administering antibiotics. Florfenicol (FF) is one of the two antimicrobial drugs permitted for aquaculture in Brazil. Due to their intensive use, potentially harmful effects on aquatic organisms are of great concern. In this sense, we investigated whether the presence of FF in cultivation water could change the health parameters of Nile tilapia. For this, we evaluated hemoglobin, hematocrit, mean corpuscular hemoglobin (MCHC) concentration, mean corpuscular volume (MCV), total plasma protein (TPP), number of circulating red blood cells and leukocytes, as lipid peroxidation levels, catalase activity and glutathione S-transferase activity of fish exposed to 11.72 mg L-1 of FF in water for 48 h. The fish were divided into two groups: Nile tilapia in water with FF or without FF (control). Exposure to FF in cultivation water for a short period didn't change the hematological variables analyzed, but caused changes in liver ROS (Reactive oxygen species) markers of the Nile tilapia, which was revealed by lipid peroxidation levels, catalase activity, and glutathione S-transferase. The 48h exposure period was enough to induce oxidative stress in hepatocytes, causing cellular oxidative damage. Therefore, the antibiotic florfenicol may cause toxicity to organisms and aquatic ecosystems, even at a sublethal concentrations near 1/100 LC50-48h for fish species.

Effects of Artemisia annua alcohol extract on physiological and innate immunity of Nile tilapia (Oreochromis niloticus) to improve health status.

Plants are a potential source of active molecules and are environmentally safer and cheaper than synthetic antibiotics. Bioactive compounds of Artemisia annua have shown pharmacological activities and are used globally as a supplement. The present study tested whether dietary supplementation with alcohol extract of the plant A. annua (ae-Aa; patent BR10201902707) improves the health status of juvenile Nile tilapia and increases resistance to diseases when fish are challenged with the bacteria Aeromonas hydrophila. The experimental design was completely randomized with four experimental groups (0.0, 0.1, 0.25, and 0.5% ae-Aa in the diets) with five repetitions (12 fish per repetition/experimental unit). We assessed serum glucose and cortisol levels in plasma, leukocyte respiratory activity, total plasma protein, serum lysozyme levels, as well as the number of circulating red blood cells and fish leukocytes at the end of the 30 days of feeding (phase I) and 24h after exposure to bacteria (phase II). The levels of lipid peroxidation, catalase activity and glutathione S-transferase of fish were also analyzed. The supplementation of 0.5% of ae-Aa was sufficient to increase the respiratory burst of leukocyte and lysozyme activity, total plasma protein, blood thrombocytes, neutrophils and monocytes after bacterial challenge (P < 0.05), and minimized stress response with decreases in plasmatic glucose and cortisol, and reduction in lipid peroxidation levels (P < 0.05). Results of the present study suggest that ae-Aa as a dietary supplement has benefits, including supplementation with 0.5% A. annua extract for 30 days to minimize the stress response and modulate innate immunity in Nile tilapia, providing fish with greater resistance and disease protection.

Glucan-MOS® improved growth and innate immunity in pacu stressed and experimentally infected with Aeromonas hydrophila.

We tested the efficacy of a commercial product (Glucan-MOS®) derived from yeast Saccharomyces cerevisiae, containing two combined products, ß-1,3-1,6 glucans and mannans on the growth, feed efficiency, stress and innate immune responses of juvenile pacu (Piaractus mesopotamicus) after a stressful handling and bacterial inoculation. For this, we evaluated the serum cortisol and plasma glucose levels, the respiratory activity of leukocytes, the serum lysozyme levels, as well as the number of circulating erythrocytes and leukocytes of fish fed during 30 days with diets containing increased levels of Glucan-MOS (0.0, 0.1, 0.2, 0.4 and 0.8%). The supplementation of 0.1% improved weight gain, feed conversion and the protein efficiency ratio compared to a control diet. The 0.2 and 0.4% Glucan-MOS® diets were sufficient to increase the respiratory burst of leukocytes and lysozyme activity, the number of thrombocytes, neutrophils and monocytes in the blood after a stressful handling and bacterial challenge, and minimized stress response as shown by decreased cortisol and glucose levels when compared to the control. The results of this work reinforce the benefits of the adoption of feeding strategies including combination of both ß-1,3-1,6 glucans and mannans as a dietary supplement in periods prior to intensive management. The 30-day period was sufficient to stimulate growth performance, improve nutrient utilization, minimize stress response and modulate innate immunity responses.

Diet of two sit-and-wait lizards, Phyllopezus pollicaris (Spix, 1825) (Phyllodactylidae) and Hemidactylus mabouia (Moreau de Jonnès, 1818) (Gekkonidae) in a perianthropic area of Mato Grosso do Sul, western Brazil

The dietary compositions of two sit-and-wait lizard species, Hemidactylus mabouia and Phyllopezus pollicaris, which co-occur over rocky substrate and vertical rock walls in a perianthropic area of western Brazil, were described. Both species showed a generalist feeding pattern, feeding mainly on insects. The most frequent prey items in the diet of P. pollicaris were Coleoptera, Araneae and Homoptera whereas the most important were Coleoptera and Homoptera, respectively. For H. mabouia the most frequent prey items were Araneae followed by Coleopterae and Hemiptera, whereas the most important items were H. mabouia followed by Formicidae and Hemiptera. Our identification into broader prey-types categories (i.e., order or family-level) suggests that some degree of food resource partitioning may occur, possibly through the occupation of different temporal niches.

A composição da dieta de duas espécies de lagartos senta-e-espera, Hemidactylus mabouia e Phyllopezus pollicaris, que coocorrem sobre substratos rochosos e paredões rochosos em uma área periantrópica no oeste do Brasil, foi descrita. Ambas as espécies demonstraram um padrão de alimentação generalista, alimentando-se principalmente de insetos. As presas mais frequentes na dieta de P. pollicaris foram Coleoptera, Araneae e Homoptera enquanto que os itens mais importantes foram Coleoptera e Homoptera, respectivamente. Para H. mabouia as presas mais frequentes foram Araneae seguido de Coleoptera e Hemiptera, enquanto que os itens mais importantes foram H. mabouia seguido de Formicidae e Hemiptera. Nossas identificações de presas em categorias mais amplas (i.e., nível de ordem ou família) sugerem que certo grau de partição de recursos alimentares pode ocorrer, possivelmente através da ocupação de nichos temporais diferentes.