<b>The use of biomarkers for assessing effects of pollutant stress on fish species from a tropical river in Southeastern Brazil

Abstract

ABSTRACT. Biomarkers are measurements within an organism that respond to environmental effects and are used as tools in bioassessment programs since they reflect physiological changes induced by exposure to pollutants. The hepatosomatic index (HSI) and the condition factor (CF) in three fish species Geophagus brasiliensis, Hypostomus affinis and Hypostomus auroguttatus were used to assess effects of pollutant stress in a tropical river during two seasons (dry and wet). Fish from the least disturbed sites had the lowest condition factor (CF) and the lowest HSI, whereas those from sites near pollutant discharges had the highest CF and HSI. Higher HSI and lower CF occurred during the dry season. It is suggested that species adapted to stressful conditions take advantage on food availability from organic loads or unoccupied niches by lesser tolerant species, increasing CF. We concluded that higher HSI values were directly associated with environmental stress whereas the higher CF values are related to availability of food resources derived from organic loads or other sources. CF and HSI are simple and cost-effective, thus suitable as routine screening tools in pollution monitoring, but caution should be taken in relating changes in physiological measurements and any specific pollutant to prevent misinterpretation.Keywords: condition factor, hepatosomatic index, fishes, monitoring, rivers.O uso de biomarcadores para avaliar efeitos de estresses de poluentes sobre espécies de peixes em um rio tropical no sudeste do Brasil RESUMO. Biomarcadores são medidas dentro de um organismo que respondem a efeitos ambientais e são utilizadas em programas de bioavaliação, já que refletem alterações fisiológicas induzidas pela exposição a poluentes. O índice hepatossomático (IHS) e o fator de condição (FC) das espécies Geophagus brasiliensis, Hypostomus affinis e Hypostomus auroguttatus foram calculados em um rio tropical durante duas estações (seca e cheia). Peixes de locais menos alterados apresentaram menores FC e IHS, enquanto os de locais próximos de descargas de poluentes apresentaram maiores FC e IHS. Maiores IHS e menores FC ocorreram durante a estação seca, comparados com a estação chuvosa. É sugerido que espécies adaptadas às condições estressantes levam vantagem da disponibilidade de alimentos próxima às descargas orgânicas ou nichos não ocupados por espécies menos tolerantes, aumentado o FC. Os valores mais elevados do IHS foram diretamente associados ao estresse ambiental, enquanto os valores mais elevados FC estão relacionados com a disponibilidade de recursos alimentares derivados de descargas orgânicas ou outras fontes. FC e IHS são simples e de baixo custo, portanto, adequados como ferramentas no controle da poluição, mas cuidados devem ser tomados ao relacionar suas mudanças às medições fisiológicas ou a qualquer poluente específico para evitar efeitos de interferência.Palavras-chave: fator de condição, índice hepatossomático, peixes, monitoramento, rios.

Fish Diseases Analysis Used as Bioindicators for Water Quality and its Importance for Environmental Monitoring

“…Several analysis methods were considered as reliable to evaluate the biological response towards environmental risk so that preventive measures can be taken (Dalzochio et al, 2016). Gharred et al (2015) and Morado et al (2017) stated that biomarkers are measurements within an organism that respond to environmental effects and are used as tools in bio-assessment programs since they reflect physiological changes induced by exposure to pollutants. Studies on fish biomarkers are of great significance as they can help to evaluate organ alterations, enzymatic responses, and histological changes when exposed to polluted aquatic environment (Bassey, 2019).…”

“…According to Thophon et al (2003), Jenkins (2004), Gharred et al (2015) and Morado et al (2017), a biomarker has the advantage to elucidate the stress level through bioassay on the organism at various stages from biomolecular and histological to physiological alterations induced by environmental stressors.…”

Acetylcholinesterase inhibitory potential and lack of toxicity of Psychotria carthagenensis infusions

“…Likewise, the hepatosomatic index (HSI) of livers exposed to fresh and dry leaf extracts of P. carthagenensis did not show significant differences in relation to the control. The HSI is expressed as the relative weight of the liver as percent of the total body mass and is a usual biomarker to detect possible effects and injuries caused by environmental stressors (Morado, Araújo, & Gomes, 2017;Narra, 2016). The liver is a detoxifying organ and, when performing its function, it is more affected when under the action of some toxic substance, which may result in alteration in HSI.…”

Multibiomarker Responses to Polycyclic Aromatic Hydrocarbons and Microplastics in Thumbprint Emperor Lethrinus Harak from a South Pacific Locally Managed Marine Area

“…For example, fish health can be evaluated with Fulton's condition factor 38 and the hepatosomatic index, which are relative indications of general nutritional status and stored energy, respectively 39,40 . Both the condition factor and the hepatosomatic index of marine fishes are influenced by pollution exposure [41][42][43] . At the systemic level, there are biomarkers used to measure the activity of biotransformation enzymes.…”