Identification of reference genes for expression studies in the liver and spleen of laying hens housed in cage and cage-free systems.

Background: The liver and spleen play a pivotal role in metabolism and immune response. During stress, neuroendocrine response induces changes in gene expression, and its assessment demands the validation of the stability of the reference genes to perform relative gene expression experiments. Aim: The objective of this study was to determine the expression stability of four reference genes (GAPDH, ACTB, RNA18S, and HMBS) in the liver and spleen tissues from laying hens housed in a conventional cage (CC) and cage-free (CF) egg production systems. Methods: Liver and spleen from Hy-Line Brown hens housed in CC and CF egg production systems were used. mRNA transcript levels were determined by quantitative polymerase chain reaction (qPCR), and the gene expression stability was evaluated using geNorm, BestKeeper, and NormFinder algorithms. Results: The most stable gene from liver tissue was ACTB in CC, CF, and CC-CF groups (overall data). In the spleen, the most stable genes were GAPDH (CC), HMBS (CF), and ACTB (CC-CF). Conclusion: The ACTB gene was the most stable gene in the liver, and GAPDH and HMBS genes were stable in spleen tissues that could be used for the normalization in qPCR experiments performed in liver and spleen tissues of laying hens housed CC and CF production systems.

Thermoprotective molecules: Effect of insulin-like growth factor type I (IGF-1) in cattle oocytes exposed to high temperatures.

The adverse effects of heat stress (HS) on the welfare and productivity of cattle are the result of the associated hyperthermia and the physiological and behavioral mechanisms performed by the animal to regulate body temperature. The negative effects of HS on in vitro oocyte maturation and in vitro bovine embryo production have been reported; being one of the major concerns due to economic and productive losses, and several mechanisms have been implemented to reduce its impact. These mechanisms include supplementation of the medium with hormones, adjuvants, identification of protective genes, among others. This review aims to explore the cellular and molecular mechanisms of insulin-like growth factor-1 (IGF-1) during in vitro and in vivo maturation of bovine oocytes and its thermoprotective effect under HS. Although the supplementation of the culture medium during oocyte maturation with IGF-1 has been implemented during the last years, there are still controversial results, however, supplementation with low concentration showed a positive effect on maturation and thermoprotection of oocytes exposed to higher temperatures. Additionally, IGF-1 is involved in multiple cellular pathways, and it may regulate cell apoptosis in cases of HS and protect oocyte competence under in vitro conditions.

Diversity and distribution of macrofungi (Ascomycota and Basidiomycota) in Tolima, a Department of the Colombian Andes: an annotated checklist.

Background: Macrofungi are classified in the phylum Ascomycota and Basidiomycota and they are very important from an ecological and economic point of view. Most studies of fungi in Colombia have been carried out mainly in the Andean Region, especially in the Departments of Antioquia, Valle del Cauca and Cundinamarca. However, other Departments in the Andean Region, like Tolima, located in the Cordillera Central, are well documented for plants (4,797 species) and animals (2,983 species), but very poorly documented in terms of knowledge of fungal diversity. New information: This study provides a compiled and annotated checklist of all known macrofungi in the Department of Tolima, based on published literature and on the identification of new specimens collected from five localities of the Department. All records were updated taxonomically and we include detailed information on the localities in which they are distributed in the Department. The list includes 164 taxa distributed in 15 orders (Agaricales, Polyporales, Russulales, Boletales, Hymenochaetales, Xylariales, Auriculariales, Thelephorales, Cantharellales, Hypocreales, Pezizales, Gloeophyllales, Phallales, Tremellales, Dacrymycetales) and eighteen records in a doubtful taxa section. We present 26 new reports, 19 for Tolima and nine for Colombia. We also provide genetic and phylogenetic evidence of the occurrence of Gloeoporustelephoroides and Podoscyphavenustula in Colombia. This checklist provides the basis for future studies on species diversity and taxonomy in Tolima, by identifying the least studied taxa and ecosystems and conservation priorities.

First study on response of astrocytes in alevines of red-bellied pacu (Piaractus brachypomus) to subchronic exposure to chlorpyrifos and trichlorfon.

Background and Aim: Organophosphate pesticides (OPs) used in agricultural production pose environmental and public health risks whenever non-target organisms are exposed to them. Oxon-type OPs, such as trichlorfon (TCF) and chlorpyrifos (CPF), are frequently used in Colombia and have been detected in water bodies in the vicinity of croplands; however, their effect on aquatic organisms, especially fish, is largely unknown. The neurotoxicity of OPs includes inhibition of esterase enzymes, neuronal damage, and increased glial reactivity. This study aimed to assess the astrocytic response in the brain tissue of juvenile red-bellied pacu (Piaractus brachypomus) exposed to TCF and CPF. Materials and Methods: A 25-day subchronic assay was conducted in which juvenile red-bellied pacu were exposed to CPF and TCF. After 25 days of exposure, the fish were killed and brain samples were collected and processed for immunohistochemistry to assess the morphology and reactivity of astrocytes; glial acidic fibrillary protein was used as a biomarker. Results: The brain samples from animals under subchronic exposure to OPs for 25 days showed higher cellular density as well as changes in astrocyte phenotype characterized by shortening of cytoplasmic projections, hypertrophy, and ameboid morphology compared to those from nonexposed animals. Similarly, astrocyte hyperreactivity was detected in the optic tectum and medial longitudinal fasciculus of the exposed group. Conclusion: Immunoreactivity of brain glial cells under subchronic exposure to OPs measured through immunohistochemical tests as well as OPs-induced neuropathology may be useful as a biomarker for monitoring environmental pollution. The results also indicate that P. brachypomus is a suitable biomonitoring model for studying neurotoxicological and neurodegenerative diseases.

Survey of porcine circovirus type 2 and parvovirus in swine breeding herds of Colombia.

BACKGROUND: One of the consequences of the presentation of reproductive failures in sows is the economic losses in production because it alters the estimated values of the volume of production, decreasing the productivity of the farm. Porcine circovirosis by porcine circovirus 2 (PCV2) has been associated with reproductive disorders, and porcine parvovirus (PVP) is one of the pathological agents most related to the presentation of reproductive failure in pigs. In Colombia, there are reports of the presence of PCV2 through molecular techniques, and PVP through serum tests; however, in the department of Tolima, the prevalence of these two viruses is unknown. OBJECTIVE: In this study, the aim was to establish a report of the prevalence of viruses in five municipalities of the department of Tolima-Colombia. METHODS: Blood samples from 150 breeding sows of five municipalities in Tolima, Colombia, were obtained. Quantitative polymerase chain reaction (qPCR) was used to detect the PCV2 and PVP virus in the blood samples followed by PCR and sequencing of 16 PCR products of the amplification of the cap gene of PCV2. A phylogenetic tree was constructed to identify the genotype of the PCV2 virus. RESULTS: The presence of PCV2d in sows was detected in 135 samples (90%), as well as the identification of PVP in 2.6% of the samples. In addition, the phylogenetic analysis showed that 16 isolates were the PCV2d2 genotype. CONCLUSION: PCV2d and PVP were found to coinfect the females, and the identification of variability in regions in the predicted amino acid sequence of the PCV2 capsid may be associated with virus pathogenicity.

Gene Expression of Aquaporins (AQPs) in Cumulus Oocytes Complex and Embryo of Cattle.

Aquaporins (AQPs) are proteins with various functions related to proper cell function and early development in mammals. The aim of this study was to evaluate the presence of AQPs and determine their mRNA levels in the cumulus oocyte complex (COC) of four bovine breeds and in blastocysts of five bovine crosses. Grade I, II and III COCs were collected by ovum pick up from non-lactating heifers of the Brahaman, Holstein, Gir and Romosinuano breeds. Embryos were produced in vitro up to the blastocyst stage of the bovine ♀Gir × â™‚Holstein, ♀Holstein × â™‚Gir, ♀Brahman × â™‚Holstein, ♀Holstein × â™‚Brahman, and ♀Romosinuano × â™‚Holstein crosses. mRNA expression of AQP1-AQP12b was estimated in COC and embryos by real-time-PCR. The presence of the twelve AQPs in the COCs and bovine embryos was established. Additionally, significant differences were determined in the expression of AQP6 and AQP12b in COCs, as well as in transcripts levels of AQP4, AQP8 and AQP9 from bovine embryos. Gene expression of AQPs in COCs and bovine embryos is consistent with the previously described biological functions. This is the first report of AQPs in COC of Gir, Brahman, Holstein and Romosinuano and embryos of five crossbreeds between Bos indicus and B. taurus.

Identification of Reference Genes for Expression Studies in the Whole-Blood from Three Cattle Breeds under Two States of Livestock Weather Safety.

Real-time PCR is widely used to study the relative abundance of mRNA due to its specificity, sensitivity, and repeatability quantification. However, relative quantification requires a reference gene, which should be stable in its expression, showing lower variation by experimental conditions or tissues. The aim of this study was to evaluate the stability of the expression of five commonly used reference genes (actb, ywhaz, b2m, sdha, and 18s rRNA) at different physiological stages (alert and emergency) in three different cattle breeds. In this study, five genes (actb, ywhaz, b2m, sdha, and 18s rRNA) were selected as candidate reference genes for expression studies in the whole blood from three cattle breeds (Romosinuano, Gyr, and Brahman) under heat stress conditions. The transcription stability of the candidate reference genes was evaluated using geNorm and NormFinder. The results showed that actb, 18SrRNA, and b2m expression were the most stable reference genes for whole blood of Gyr and Brahman breeds under two states of livestock weather safety (alert and emergency). Meanwhile, actb, b2m, and ywhaz were the most stable reference genes for the Romosinuano breed.

Identification of reliable reference genes for expression studies in the magnum of laying hens housed in cage and cage-free systems.

Stress factors during poultry production can evoke changes in gene transcription and protein synthesis in the hen oviduct and could affect the internal and external egg quality. Studies of relative gene expression require the identification of the most stable reference genes for the quantitative polymerase chain reaction (qPCR) to investigate the reproductive tissues' response in laying hens kept in different production systems. The objective of this study was to determine the most stable reference genes of the magnum tissues of laying hens housed in two different production systems. Hy-Line Brown hens were reared under the same sanitary conditions until 15 weeks of age. Later on, they were transferred into two different production systems, conventional cage (CC) and cage free (CF), up to 82 weeks of age. At 50 and 60 weeks, a total of six hens from each production system were euthanized, and magnum samples were collected. The qPCR was used to determine the RNA transcription level of five reference genes, ACTB, 18S, GAPDH, MSX2 and HMBS. These genes were evaluated for transcript expression in magnum tissues by NormFinder, BestKeeper, geNorm and RefFinder software. The results indicated that the most stable gene in the CF housing system was HMBS in three of the algorithms and in the CC housing system was the 18S, and the best combination of reference genes was HMBS/GAPDH in CF and 18S/HMBS in CC. In conclusion, HMBS, 18S and GAPDH genes could be used together as reference genes for the normalization of the magnum tissues transcript expression of hens in CF and CC housing systems.

Characterization of Salmonella species from pork meat in Tolima, Colombia / Caracterización de las especies de Salmonella en carne porcina en Tolima, Colombia / Caracterização de espécies de Salmonella a partir de carne de porco em Tolima, Colômbia

Background: Salmonella is a Gram-negative bacterium and the principal cause of human gastroenteritis that originates from the consumption of animal products.Objective: to determine serotype and antibiotic resistance of Salmonella spp. isolated from pork meat and environmental samples in 6 slaughterhouses and 14 butcheries in Tolima, Colombia. Methods: slaughterhouses and butcheries were selected depending on their slaughter capacity and compliance with good manufacturing practices. Samples (n = 507) were taken from carcasses, the environment, and fomites (i.e., surfaces of knives, hooks, floor, siphons, work surfaces, and transport trucks), then cultured in Salmonella selective media. Following this, the isolated Salmonella spp. was identified using a conventional biochemical test and genus antiserum (Poli A + Vi). The Kauffman-Whyte scheme was used for serotyping and the agar diffusion method (Kirby-Bauer) was used to determine antibiotic sensitivity. Results:Manhattan, Derby, Typhimurium, Javiana, Muenster, Hvittingfoss, Sinsfort, Kattbus, and Saint Paul serotypes of Salmonella were isolated from both pork meat and environmental samples, being Derby the most common serotype. Salmonella isolates showed antibiotic multiresistance mainly to tetracycline, lincomycin and nalidixic acid. Conclusion: several Salmonella serotypes are present in slaughterhouses and meat samples from butcheries, and they show similar antibiotic resistance patterns. This work represents the first report on Salmonella serotypes in slaughterhouses and pork meat from butcheries in Tolima, Colombia.

Antecedentes: Salmonella es una bacteria Gram-negativa y la principal causa de gastroenteritis en humanos transmitida por consumo de alimentos de origen animal.Objective: determinar el serotipo y la resistencia antibiótica de Salmonella spp. aisladas de carne porcina y muestras ambientales en 6 plantas de beneficio y 14 expendios en Tolima, Colombia. Métodos:las plantas de beneficio y los expendios fueron seleccionados dependiendo del volumen de animales sacrificados y el establecimiento de las buenas prácticas de manufactura. Las muestras (n = 507) fueron tomadas de las carcasas, ambiente y fómites (i.e. superficie de cuchillos, ganchos, piso, sifones, mesones y camiones de transporte), cultivadas en medios de cultivo selectivos para Salmonella. Las Salmonella spp., aisladas fueron identificadas mediante purnas bioquímicas convencionales y antisuero de género (Poli A + Vi). La sero-tipificación fue llevada a cabo a través del esquema Kauffman-Whyte y la sensibilidad antibiótica a través del método de difusión en agar (Kirby-Bauer).. Resultados: fueron aislados los serotipos de Salmonella Manhattan, Derby, Typhimurium, Javiana, Muenster, Hvittingfoss, Sinsfort, Kattbus y Saint Paul tanto de carne porcina como muestras ambientales, siendo el serotipo Derby el más frecuente. Los aislamientos mostraron patrones de multi-resistencia antibiótica, principalmente a tetraciclina, lincomicina y ácido nalidíxico. Conclusión: diversos serotipos de Salmonella fueron aislados de muestras de plantas de beneficio y expendios de carne porcina y estos demostraron patrones similares de resistencia antibiótica. Este trabajo representa el primer reporte de serotipos de Salmonella en plantas de beneficio y expendios de carne porcina en Tolima, Colombia.

Antecedentes: a Salmonella é uma bactéria Gram-negativa e causa principal de gastroenterite humana transmitida por consumo de produtos de origem animal. Objetivo: determinar o serotipo e de resistência a antibióticos de Salmonella spp. isolada a partir de carne de porco e amostras ambientais em 6 frigoríficos e lojas 14 açougues em Tolima, Colômbia. Métodos: abatedouros e açougues foram selecionados de acordo com o volume de animais sacrificados eo estabelecimento de boas práticas de manufatura. As amostras (n = 507) foram retirados de cadáveres, meio ambiente e fômites (ou seja, superfícies de facas, ganchos, piso, sifões, mésons e caminhões de transporte), cultivadas em meios de cultura de Salmonella seletiva e a isolada Salmonella spp., foram identificados usando e anti-soro de teste género bioquímica convencional (Poli A + Vi). A sorotipagem foi realizada utilizando esquema de Kauffman-Whyte e teste de sensibilidade aos antibióticos foi feito pelo método de difusão em ágar (Kirby-Bauer). Resultados: ''o'' sorotipos de Salmonella de Manhattan,= o surotipos de Salmonella Derby, Typhimurium, Javiana, Muenster, Hvittingfoss, Sinsfort, Kattbus e Saint Paul foram isolados de ambas as carnes de porco e amostras ambientais, sendo o sorotipo Derby o mais frequente. Os isolados de Salmonella apresentaram padrões de multirresistência aos antibióticos, principalmente para tetraciclina, lincomicina e ácido nalidíxico. Conclusão: vários sorotipos de Salmonella estão presentes em matadouros e lojas amostras de carne de porco de talho e mostram padrões similares de resistência a antibióticos. Este trabalho representa o primeiro relato de sorotipos de Salmonella em abatedouros e açougues de carne de porco em Tolima, Colômbia.

Efectos inmunotoxicológicos e histopatológicos de la exposición a concentraciones subletales de cloruro de mercurio (HgCl2) en cachama blanca (Piaractus brachypomus) / Immunotoxicological and histopathological effects of exposure to sublethal concentrations of mercuric chloride (HgCl2) in red-bellied pacu (Piaractus brachypomus) / Avaliação imunotoxicológica e histopatológica da exposição a concentrações subletais de cloreto de mercúrio (HgCl2) em Pirapitinga branca (Piaractus brachypomus)

Resumen El mercurio es un contaminante xenobiótico encontrado frecuentemente en ecosistemas naturales, representando un aspecto relevante en salud pública y ambiental debido a los niveles encontrados en fuentes de agua en correlación con la bioacumulación en organismos vivos. El objetivo fue evaluar los efectos inmunotoxicológicos e histopatológicos de la exposición a concentraciones subletales de Cloruro de Mercurio (HgCl2) en cachama blanca (Piaractus brachypomus). Se utilizaron alevinos de cachama blanca, con un peso de 10 ± 2,1 g, distribuidos en acuarios con aireación constante, sin filtro. El periodo experimental fue de 18 días, utilizando 4 concentraciones basadas en la décima parte de la CL50 descrita para cachama, así como un grupo control. Se realizaron seis muestreos (días 1, 2, 4, 7, 12 y 18) en los cuales se tomaron muestras de sangre para la evaluación de la explosión respiratoria y la capacidad bactericida del plasma. Se calculó el índice hepatosomático y se tomaron muestras para procesamiento histopatológico. Se evidenció una elevación del nivel de explosión respiratoria (estrés oxidativo) en animales expuestos a HgCl2 de una manera dependiente de la concentración, siendo más marcado este efecto al día 12 de exposición. No se encontraron diferencias significativas en los valores de índice hepatosomático (IHS). En la actividad bactericida del plasma se halló una actividad menor en animales expuestos a HgCl2. En el análisis histopatológico se encontraron cambios como hiperplasia, aneurismas y sinequias en branquias; inclusiones hialinas en hígado y centros melanomacrófagos en riñón. Los alevinos de cachama blanca expuestos a dosis subletales de HgCl2, muestran un incremento significativo en la explosión respiratoria (estrés oxidativo), así como cambios en la actividad bactericida del plasma, además de cambios anatomopatológicos a nivel branquial, hepático y renal.

Mercury is a xenobiotic contaminant often found in natural ecosystems. It is relevant for public and environmental health because of the existing correlation between its content in water sources and mercury bioaccumulation in living organisms. This work assessed the immune and histopathological effects of exposure to sublethal concentrations of mercury chloride (HgCl2) in Pacu (Piaractus brachypomus). Pacu fingerlings weighing 10 ± 2.1 g were distributed in constantly aerated tanks with no filter. The experimental period was 18 days. A negative control group and four Hg levels were used based on the tenth of LC50 for Pacu. Six blood samples were taken on days 1, 2, 4, 7, 12 and 18 to measure respiratory burst and bactericidal activity of the plasma. The hepatosomatic index was calculated and samples were taken for histopathological examination. Increased respiratory burst (oxidative stress) was observed in animals exposed to HgCl2 in a concentration-dependent manner. This effect was more pronounced at day 12 of exposure. Hepatosomatic index (HSI) values showed no significant differences. Animals exposed to HgCl2 showed low bactericidal activity of plasma. Histopathological changes such as hyperplasia, aneurysms and synechiae were found in gills, while hyaline inclusions were observed in liver and melanomacrophage centers in kidney. Pacu fingerlings exposed to sublethal doses of HgCl2 had a significant increase in oxidative stress and changes in plasma bactericidal activity in addition to pathological changes in the gills, hepatic and renal tissues.

O mercúrio é um contaminante xenobiótico encontrado frequentemente nos ecossistemas naturais, o qual representa um aspecto muito importante na saúde pública e ambiental devido aos níveis encontrados nas fontes de agua, as quais além, tem correlação com a bioacumulação em organismos vivos. O objetivo desta pesquisa foi avaliar os efeitos imunotoxicológicos e histopatológicos da exposição a concentrações subletais de Cloreto de Mercúrio (HgCl2) em Pirapitinga branca (Piaractus brachypomus). Utilizaram-se alevinos de Pirapitinga branca com um peso médio de 10 ± 2,1 g, distribuídos em aquários com tanques de aireação constante sem filtro. O período experimental foi de 18 dias, utilizando quatro concentrações baseadas na decima parte da CL50 descrita para Pirapitinga branca assim como no grupo controle. Realizaram-se seis amostragens (dias 1, 2, 4, 7, 12 e 18) nos quais tomaram-se amostras de sangue para a avaliação da explosão respiratória e a capacidade bactericida do plasma. Calculou-se o índice hepatosomático e pegaram-se amostras para processamento histopatológico. Evidenciou-se uma elevação do nível de explosão respiratória (estresse oxidativo) em animais expostos ao HgCl2 de uma maneira dependente da concentração, sendo mais marcado este efeito ao dia 12 da exposição. Não se encontraram diferenças significativas nos valores do índice hepatosomático (IHS). Na atividade bactericida do plasma achou-se uma atividade menor em animais expostos ao HgCl2. Na análise histopatológica encontraram-se mudanças como hiperplasia, aneurisma e sinéquias em brânquias, inclusões hialinas no fígado e centros melanomacrófagos nos rins. Os alevinos de Pirapitinga branca expostos a doses sub-letais de HgCl2, amostraram um incremento significativo na explosão respiratória (estresse oxidativo) assim como mudanças na atividade bactericida do plasma, além de mudanças anatomopatológicas no nível branquial, hepático e renal.

Acute toxicity and histopathological alterations of Roundup® herbicide on "cachama blanca" (Piaractus brachypomus) / Toxicidade aguda e alterações histopatológicas induzidas pelo herbicida Roundup® em pirapitinga (Piaractus brachypomus)

Acute toxicity of the glyphosate -N (phosphonomethyl) glycine- herbicide, Roundup®, in juveniles of cachama blanca, (Piaractus brachypomus), was evaluated and the histopathological lesions were assessed. The 96 h lethal concentration 50 was 97.47mg.L-1 (P<0.05). In the gill, necrotic and proliferative lesions were detected. In the liver, congestion, degenerative foci, hyaline droplets and lipidic vacuolization of the hepatocytes were observed. In the stomach mild hyperplasia of mucous cells was detected, which was also observed in the skin. In this latter tissue, a large increase in the thickness of the epidermis with necrotic lesions, infiltration of leukocytes and melanin pigment were observed. In the brain, degenerative foci of neuronal bodies in the telencephalon associated with gliosis and infiltration of eosinophilic granule cells/mast cells were shown. In conclusion, gills, liver, skin and brain are susceptible to Roundup®. Moreover, effects on the central nervous system could affect olfaction as well as individual and group behavior, the reproductive performance of the fish and hence have repercussions at the population level.

Este estudo avaliou a toxicidade aguda e as alterações histopatológicas induzidas pelo glifosato -N (fosfometil) glicina, na formulação Roundup® em juvenis de pirapitinga (Piaractus brachypomus) expostos durante 96 horas. A concentração letal 50 foi de 97.47mg.L-1 (P<0.05). Nas brânquias foram achadas lesões proliferativas e necróticas. No fígado foi observada congestão, processos degenerativos, gotas hialinas e presença de vacúolos lipídicos nos hepatócitos. No estomago e na pele foi detectada hiperplasia ligeira das células de moco. Nesta ultima, adicionalmente foi observado engrossamento da epidermes com lesões necróticas, infiltração de células leucocitárias e acumulação de melanina. No cérebro foram observados focos de degeneração de somas neurais na região do telencéfalo junto com gliose e infiltração de células granulais eosinofilicas/células mast. Concluindo, as brânquias, o fígado, a pele e o cérebro são órgãos suscetíveis ao Roundup®. Adicionalmente, os efeitos sobre o sistema nervoso central poderiam reduzir a olfação nos peixes, tanto como o comportamento grupal e individual, a performance reprodutivo e desta forma, repercutir no nível populacional.

Evaluación de los efectos tóxicos y concentración letal 50 del surfactante Cosmoflux® 411F sobre juveniles de cachama blanca (Piaractus brachypomus) / Assessment of toxic effects and lethal concentration 50 of surfactant Cosmoflux® 411F on juveniles of cachama blanca (Piaractus brachypomus)

En Colombia, el surfactante Cosmoflux® 411F es usado en fumigaciones de cultivos ilícitos para mejorar la efectividad del glifosato. El uso del Cosmoflux® 411F no está soportado por estudios toxicológicos. Los objetivos del presente trabajo fueron determinar las lesiones anatomopatológicas derivadas de la exposición al Cosmoflux® 411F y establecer la concentración letal 50 (CL50) a 96 horas en cachama blanca (Piaractus brachypomus). Se utilizaron juveniles de cachama blanca (40 g) en dos experimentos: 1) toxicidad subletal (n =126) y, 2) determinación de la CL50 (n =84). Las concentraciones del ensayo de toxicidad subletal fueron: 0 mg/l (Tratamiento 0), 0.17 mg/l (Tratamiento 1), 0.34 mg/l (Tratamiento 2), 0.68 mg/l (Tratamiento 3), 1.36 mg/l (Tratamiento 4), y 2.72 mg/l (Tratamiento 5), en sistema semiestático. Para determinar la CL50 las dosis fueron: 3000, 3450, 3900, 4350 y 4800 mg/l de Cosmoflux® 411F. La CL50 obtenida fue de 4417.99 mg/l. En los peces se evidenció leve disminución de la actividad de nado. A la necropsia se halló palidez del hígado y acumulación de material mucoso en las branquias. Por histopatología se halló: vacuolización de hepatocitos, hiperplasia de células epiteliales, de cloro y caliciformes branquiales, vacuolización de enterocitos, aumento de centros melanomacrófagos renales, gliosis, degeneración neuronal e infiltración de células granulares eosinofílicas/células mastocitos en telencéfalo. Los hallazgos concuerdan con lo reportado en peces expuestos a surfactantes, exceptuando las lesiones del sistema nervioso central que pueden tener consecuencias sobre interacciones sociales, de alimentación y reproducción de la especie; siendo necesario profundizar la investigación sobre dicho efecto. El hígado, branquias y piel constituyen órganos blanco de la acción tóxica. La CL50 hallada (4417.99 mg/l) es alta comparada con lo reportado en surfactantes no-iónicos.

In Colombia, surfactant Cosmoflux® 411F is used for the fumigation of illicit crops in order to improve the glyphosate herbicide activity. The use of Cosmoflux® 411F is not supported by toxicological surveys. The aims of this study were to determinate the anatomopathological lesions due to the exposure to Cosmoflux® 411F and to establish lethal concentration 50 (LC50) to 96 hours in cachama blanca (Piaractus brachypomus). Juveniles of cachama blanca (40 g) in two assays were used: 1) sublethal toxicity (n= 126) and 2) determination of LC50 (n=84). Sublethal toxicity assay concentrations were: 0 mg/l (Treatment 0) 0.17 mg/l (Treatment 1), 0.34 mg/l (Treatment 2), 0.68 mg/l (Treatment 3), 1.36 mg/l (Treatment 4), and 2.72 mg/l (Treatment 5); through semi-static system. For the determination of LC50 of Cosmoflux® 411F 3000, 3450, 3900, 4350 y 4800 mg/l concentrations were used. LC50 was 4417.99 mg/l. Animals showed slight decrease in swimming activity. At necropsy examination were found paleness in liver and whitish material accumulation in top of gill filament. Histopathologically, it was found fatty degeneration and hepatocyte vacuolization, epithelial cells, chloride cells and mucous cells hyperplasia, enterocyte vacuolization, increase in the expression of melanomacrophage centres in kidney, gliosis, neuronal degeneration and infiltration of eosinophilic granule cells/mast cells in telencephalon. With exception of central nervous system lesions, the findings are according to the reported in literature about surfactant exposure in fish. Central nervous system effects can have consequences on feeding, reproductive and social interactions, due to close telencephalon/olfactory system relationship, being necessary to deep in research to these processes. In same way, liver, gills and skin are target organs of toxic action of this xenobiotic. LC50 is high (4417.99 mg/l) compared with that reported for other nonionic surfactants.