Metabolic responses to trophic habits of Ramnogaster arcuata

BLASINA G.E.; RONDA A.C.; MOLINA J.M.; LOPEZ CAZORLA A.C.

Mar del Plata

Congreso; XVIII Congreso Latinoamericano de Ciencias del Mar-COLACMAR; 2019

Trophic habits of fish condition their wellbeing and different types of diets can produce different effects on their metabolic responses. Under hypothesis that different metabolic responses will be found according to the trophic habits, we aim to determine the possible effects of diet variations on the metabolism of the clupeid Ramnogaster arcuata. To cover the environments where the specie inhabiting, two sites were selected in Bahía Blanca Estuary (BBE) and in the adjacent coastal zone (ACZ). A total of 142 individuals were caught in BBE and 35 in the ACZ. Fish, between 1 and 2 years old, were chosen and analyzed according to its total length (Lopez Cazorla and Sidorkewicj, 2009). Fulton´s condition index (K) and the diet composition were determined. The liver was extracted and lipid peroxidation, according to the thiobarbituric acid reactive substances (TBARs) method, protein content, and metabolic enzymes activities (Aspartate aminotransferase?AST and Alanine aminotransferase?ALT) were determined. We performed correlation analyses between parameters that presented variation among sites. Condition index, trophic ecology (including feeding activity and diet composition) and liver metabolism (ALT/AST activity and TBARSlevels) were significantly different between BBE and ACZ. Consumption of mysids was positively correlated with ALT and negatively correlated with TBARs; whileconsumption of ostracods showed a negative correlation with ALT. Activities of ALT and AST correlated positively each other, indicating that if one of these enzymes is activated or inhibited, the other shows the same pattern. Moreover, ALT/AST activities positively correlated with K while a negative correlation between K and TBARs was observed (Figure). Our results indicate that diet composition has a strong influence in body condition metrics, as well as in the enzymatic activity. Biologic and metabolic responses observed in R. arcuata would change according to different food quality or food availability consumed in BBE and ACZ.