Effect of 17α-ethinylestradiol (EE2) as a reproductive endocrine disruptor in the fish Aequidens metae

El 17α-etinilestradiol (EE2) es un esteroide sintético que interfiere en el sistema endócrino reproductivo de los peces. En este estudio se evaluó el efecto del EE2 como posible perturbador endócrino en hembras y en machos adultos de Aequidens metae expuestos a 0.5, 5, 50 y 250 ng/L por 21 días. Se incluyó un testigo negativo (C) y un testigo con solvente (etanol) (CE). Finalizada la exposición al EE2, la sangre fue colectada para determinar calcio y fósforo plasmático y en las gónadas e hígado se evaluaron los índices somáticos y las alteraciones histológicas. Los índices gonadosomático y hepatosomático no presentaron diferencias significativas. A nivel histológico, en los ovarios se encontró congestión, fibrosis intersticial, apoptosis, atresia y material vitelogénico. A nivel testicular, se observó acumulación de material de melanomacrófagos, degeneración testicular, fibrosis intersticial, atrofia y engrosamiento de la pared intersticial. Y en hígado, en ambos sexos, se observó mayor picnosis degenerativa, activación de macrófagos, apoptosis, infiltraciones, dilatación y congestión, en comparación con los grupos testigo. Las hembras no presentaron diferencias significativas en calcio y fósforo plasmático. Los machos expuestos a las tres concentraciones más altas tuvieron valores significativamente mayores en el calcio plasmático en comparación con el grupo testigo. Con respecto al fósforo plasmático, en los machos expuestos a 250 ng/L se presentaron diferencias en comparación con el grupo testigo. Estos resultados permiten inferir que esta especie es sensible a los efectos de la perturbación endocrina generados por el EE2, y que la determinación de parámetros bioquímicos como los iones de calcio y fósforo pueden ser usados como biomarcadores adicionales del estado de salud de los peces expuestos a xenobióticos.The 17α-ethinylestradiol (EE2) is a synthetic steroid that interferes with the reproductive endocrine system of fish. This study evaluated the effect of EE2 as a possible endocrine disruptor in adult Aequidens metae females and males exposed to 0.5, 5, 50, and 250 ng/L for 21 days. Negative control and solvent control (ethanol) were included. After exposure, blood was collected to determine plasma calcium and phosphorus, and somatic indices and histology changes were evaluated in the gonads and liver. The gonadosomatic and hepatosomatic indices did not present significant differences. At histological level, congestion, interstitial fibrosis, apoptosis, atresia, and vitellogenic material were found in the ovary. At the testicular level, accumulation of melanomacrophage material, testicular degeneration, interstitial fibrosis, atrophy and thickening of the interstitial wall were observed. In the liver, in both sexes, was observed greater degenerative pyknosis, activation of macrophages, apoptosis, infiltrations, dilatation and congestion compared with the control groups. Females did not show significant differences in plasma calcium and phosphorus between treatments. The males exposed to the three highest EE2 concentrations had significantly higher values in plasma calcium compared to control group. Regarding plasma phosphorus, in males exposed to 250 ng/L there were differences compared to control groups. The results allow inferring that this species is sensitive to endocrine disruption effects generated by EE2 and that the determination of biochemical parameters such as plasma calcium and phosphorus ions can be used as additional biomarkers of the health status of fish exposed to xenobiotics.Fil: Pahí Rosero, Ana María. Universidad de Los Llanos; Colombia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Velasco Santamaría, Yohana María. Universidad de Los Llanos; Colombi

Evaluación del efecto del hidrocarburo fenantreno sobre el crecimiento de chlorella vulgaris (chlorellaceae)

Se evaluó el efecto del hidrocarburo policíclico aromático fenantreno sobre el crecimiento de la microalga Chlorella vulgaris  bajo condiciones de laboratorio. Las microalgas fueron expuestas a diferentes concentraciones de fenantreno (0, 1, 10, 100, 1000 y 10000 μg/l). El tiempo de exposición fue de 72 h, determinándose diariamente la densidad algal mediante recuento en cámara de Neubauer. Se determinó la tasa promedio de crecimiento, la biomasa total y el porcentaje de inhibición de la biomasa. También se evaluó el contenido de clorofila a, al inicio y final del experimento. Los ensayos fueron realizados en recipientes de vidrio de 0,4 l, utilizando como medio de cultivo fertilizante inorgánico del complejo NPK (REMITAL® m – 17-6-18) a razón de 1 g/l. Los resultados mostraron que el fenantreno inhibió progresivamente el crecimiento de la microalga, observándose el menor crecimiento celular en el medio con la mayor concentración de fenantreno, el cual alcanzó un porcentaje de inhibición del crecimiento del 59 %. Las tasas de crecimiento diario se mantuvieron relativamente constantes en los demás tratamientos. La concentración de clorofila a, medida mediante espectrofotometría, no se afectó por las diferentes concentraciones del hidrocarburo. En conclusión, el crecimiento de la microalga C. vulgaris  puede afectarse negativamente por la exposición a concentraciones nominales superiores a 1 μg/l de fenantreno

Seroprevalence of exposure to SARS-CoV-2 in domestic dogs and cats and its relationship with COVID-19 cases in the city of Villavicencio, Colombia [version 3; peer review: 2 approved]

Background: Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak, different animal species have been implicated as possible intermediate hosts that could facilitate the transmission of the virus between species. The detection of these hosts has intensified, reporting wild, zoo, farm, and pet animals. The goal of this study was to determine the seroprevalence of anti-SARS-CoV-2 immunoglobulins (IgG) in domestic dogs and cats and its epidemiological association with the frequency of coronavirus disease 2019 (COVID-19) patients in Villavicencio, Colombia. Methods: 300 dogs and 135 cats were randomly selected in a two-stage distribution by clusters according to COVID-19 cases (positive RT-qPCR for SARS-CoV-2) within the human population distributed within the eight communes of Villavicencio. Indirect enzyme-linked immunosorbent assay (ELISA) technique was applied in order to determine anti-SARS-CoV-2 IgG in sera samples. Kernel density estimation was used to compare the prevalence of COVID-19 cases with the seropositivity of dogs and cats. Results: The overall seroprevalence of anti-SARS-CoV-2 IgG was 4.6% (95% CI=3.2-7.4). In canines, 3.67% (95% CI=2.1-6.4) and felines 6.67% (95% CI=3.6-12.18). Kernel density estimation indicated that seropositive cases were concentrated in the southwest region of the city. There was a positive association between SARS-CoV-2 seropositivity in pet animals and their habitat in Commune 2 (adjusted OR=5.84; 95% CI=1.1-30.88). Spearman's correlation coefficients were weakly positive (p=0.32) between the ratio of COVID-19 cases in November 2020 and the results for domestic dogs and cats from the eight communes of Villavicencio. Conclusions: In the present research cats were more susceptible to SARS-CoV-2 infection than dogs. This study provides the first positive results of anti-SARS-CoV-2 ELISA serological tests in domestic dogs and cats in Colombia with information about the virus transmission dynamics in Latin America during the COVID-19 pandemic

SUBLETHAL EFFECTS OF ENDOSULFAN ON HEALTH AND REPRODUCTION OF ADULT ZEBRAFISH (Danio rerio)

In order to evaluate the sublethal effects of endosulfan on zebrafish (Dan/o rerio), adult were exposed for 28 d to 0, 0.16 and 0.48 pg.l"^ and sampling at 0, 14 and 28 days. Blood cell count, ion concentrations, total protein, TBARS, Na*K*-ATPase and vitellogenin were determined in whole-fish. Likewise, liver and gills histology were determined. Fifteen days after the end of endosulfan exposure, reproduction was stimulated. Fertilization and total fecundity, heart beat frequency (Hf), notochordal length, volume of the yolk sac (Vys) and abnormalities in larvae were determined. During the first 14 d of exposure, fish exposed to 0.16 pg.l showed a significantly lower red blood cell (1.48 x 10"^ cells.pl'^) and white blood cell counts (7.3 x 10"^ cells.pr^) than fish exposed to 0.48 pg.|-^ (2.65 x 10"^ cells.pr^ and 11.3 x 10^^ c e l l s . p l\ respectively) (p < 0.05). The Na* concentration of fish exposed to 0.16 pg.l'^ was significantly higher (p < 0.05) than the control group. Fish exposed to 0.16 pg.l"^ showed a significant increase (p < 0.05) in T B A R S concentration (41.3 ± 2.1 nmol.mg protein"^) than control group (34.2 ± 1.5 nmol.mg protein"^). Fish exposed to 0.16 and 0.48 pg.l"' showed an increase of the Na*K*-ATPase activity (4.12 ± 1.05 and 4.56 ± 1.09 pmol Pi.mg protein'\h"\ respectively) than fish of the control group (1.02 ± 0.26 pmol Pi.mg protein"\h"^). On day 14 the number of hepatocytes in fish exposed to 0.16 and 0.48 pg.l"^ was significantly lower (p < 0.05) than the control group. The hepatocyte diameter in fish of the control group was significantly lower (p < 0.05) than those exposed to endosulfan at 14 and 28 d of exposure. The severity of lamellar hyperplasia increased with the endosulfan concentration. IVIales exposed to the low concentration had similar values of V TG as females. There were no treatment-dependent effects on fertility and GSI (p > 0.05); nevertheless, fish exposed to 0.16 pg.l"^ showed high HSI (6.1 ± 2.3 %) and a significant decrease (p < 0.05) in both total fecundity (214 ± 35) and Hf (120 ± 3 beats.min'^). Severe lordosis and ascitis were observed in larvae from the fish exposed to 0.16 and 0.48 pg.l"\ Vys was higher (p < 0.05) in larvae of fish exposed to 0.48 (124.8 ± 4 pm^) and 0.16 pg.l"^ (95.6 ± 6 pm^) than in the respective control group (102.1 ± 5 pm^ and 75.5 ± 5 pm^). These findings show that sublethal concentrations of endosulfan produce haematological and biochemical effects in Danio rerio. Likewise, endosulfan affects reproduction and larval development of zebrafish, with potential impacts on the perpetuation of this species. Keywords: blood cells, fish, insecticide, larvae, oxidative stress, reproduction.Faculty of Science

Características morfológicas, morfométricas, merísticas y manejo de la primera alimentación de larvas de escalar altum (Pterophyllum altum) (Pellegrin, 1903)

The altum angelfish is a representative species of the South American ichthyofauna due to it`s wide acceptability in the aquarium`s market, making it a species with great productive potential. In this study, a morphological description, detail of meristic parameters during its first life stages and aspects of first feeding were evaluated. Ten broodstock couples were kept in 50 L aquariums with aeration and constant temperature. After the breeding, 15 larvae/h were collected every hour until 75 hours post-hatching (HPH) and fixed in 4% buffered formalin for the analysis of the meristic and morphological characteristics. Likewise, different diets with Artemia salina nauplii (T1), capsulated Artemia salina cyst (T2) and wild zooplankton (T3) were offered to the larvae to determine some productive aspects. The P. altum larvae has cylindrical and rounded body, elongated tail and an ovoid yolk sac which is evident until it`s development as post-larvae. Regarding its morphometric characteristics, the larvae had a total length of 4.64±0.5 mm, standard length of 3.8±0.2 mm, eye diameter of 0.49±0.2 mm, head length of 0.71±0.8 mm and body height of 0.76±0.6 mm at 75 HPH. No significant differences between treatments were observed in the final weight (P>0.05); however, differences in the specific growth rate and in the survival were observed (P 0,05) nos pesos finais. No entanto, diferenças significativas (P 0.05), en los pesos finales. Sin embargo, se observaron diferencias (P<0.05) en la tasa de crecimiento especifico y en la sobrevivencia. Como conclusión, las larvas de P. altum presentan un crecimiento acelerado hasta el segundo día de vida, debido a la disminución de la relación entre las características morfométricas. Por otro lado, el mejor desempeño productivo se observó en los individuos alimentados con nauplios de artemia, constituyéndose en una importante alternativa como fuente de alimento durante la larvicultura de esta especie

Morphological, morphometric and meristic characteristics of larvae of altum angelfish (Pterophyllum altum) (Pellegrin, 1903) and management of its first feeding

El escalar altum ha sido una especie representativa de la ictiofauna suramericana por su amplia aceptación en el mercado de la acuariofilia, lo que lo convierte en una especie con gran potencial productivo. En el presente estudio se realizó una descripción morfológica, detalle de algunos parámetros merísticos de los primeros estadios de vida de larvas de P. altum y aspectos de su primera alimentación. Se utilizaron diez parejas de reproductores mantenidas en acuarios de 50 L, con aireación y temperatura constante. Luego del proceso de reproducción se tomaron 15 larvas/h hasta las 75 horas poseclosión, (HPE) estas fueron fijadas en formol bufferado al 4% para posterior descripción de las características merísticas y morfométricas. Así mismo, se suministraron diferentes dietas luego de la reabsorción del saco vitelino, así: (T1) larvas alimentadas con nauplios de Artemia salina, (T2) cistos de Artemia salina decapsulados, y (T3) zooplancton silvestre para determinar algunos parámetros productivos. Morfológicamente, las larvas de P. altum tienen un cuerpo cilíndrico, redondeado, cola alargada y saco vitelino ovoide evidente hasta su desarrollo en postlarva. En cuanto a sus características morfométricas, presentaron una longitud total promedio de 4.64±0.5 mm, una longitud estándar de 3.8±0.2 mm, el diámetro del ojo de 0.49±0.2 mm, así como una longitud de de cabeza 0.71±0.8 mm y la altura del cuerpo de 0.76±0.6 mm a las 75 HPE. Con el suministro de las diferentes dietas no se observaron diferencias estadísticas significativas (P&amp;gt;0.05), en los pesos finales. Sin embargo, se observaron diferencias (P&amp;lt;0.05) en la tasa de crecimiento especifico y en la sobrevivencia. Como conclusión, las larvas de P. altum presentan un crecimiento acelerado hasta el segundo día de vida, debido a la disminución de la relación entre las características morfométricas. Por otro lado, el mejor desempeño productivo se observó en los individuos alimentados con nauplios de artemia, constituyéndose en una importante alternativa como fuente de alimento durante la larvicultura de esta especieThe altum angelfish is a representative species of the South American ichthyofauna due to it`s wide acceptability in the aquarium`s market, making it a species with great productive potential. In this study, a morphological description, detail of meristic parameters during its first life stages and aspects of first feeding were evaluated. Ten broodstock couples were kept in 50 L aquariums with aeration and constant temperature. After the breeding, 15 larvae/h were collected every hour until 75 hours post-hatching (HPH) and fixed in 4% buffered formalin for the analysis of the meristic and morphological characteristics. Likewise, different diets with Artemia salina nauplii (T1), capsulated Artemia salina cyst (T2) and wild zooplankton (T3) were offered to the larvae to determine some productive aspects. The P. altum larvae has cylindrical and rounded body, elongated tail and an ovoid yolk sac which is evident until it`s development as post-larvae. Regarding its morphometric characteristics, the larvae had a total length of 4.64±0.5 mm, standard length of 3.8±0.2 mm, eye diameter of 0.49±0.2 mm, head length of 0.71±0.8 mm and body height of 0.76±0.6 mm at 75 HPH. No significant differences between treatments were observed in the final weight (P&amp;gt;0.05); however, differences in the specific growth rate and in the survival were observed (P&amp;lt;0.05). The best productive performance was observed in individuals fed with Artemia nauplii. As a conclusion, P. altum larvae exhibit rapid growth until the second day of life, due to the decreased in the relationship between the morphometric characteristics. In the other hand, the best productive performance was observed in animal’s brine shrimp nauplii individuals, becoming an important alternative food source during the larval rearing of this species