Antinutritional effect of lectin from faveira (Parkia platycephala) seeds in tambatinga (Colossoma macropomum x Piaractus brachypomus)

This study investigated the possible antinutritional effects of Parkia platycephala lectin (0, 20, 40, or 60 mg kg-1 of diet) on tambatinga feeding for 60 days as well as methods of inactivating this protein. Weight gain, specific growth rate, and relative weight gain decreased, and the feed conversion rate increased with the increase in dietary lectin. The hepatic glycogen levels of fish fed 60 mg kg-1 were higher than those of fish fed 20 and 40 mg kg-1. Diets containing 40 and 60 mg kg-1 increased muscle glucose levels compared to the control group. Fish-fed diets containing lectin showed reduced muscle glycogen compared to those receiving the control diet. Fish fed 60 mg kg-1 presented lower muscle protein levels than those fed 20 mg kg-1. In vitro tests showed that the hemagglutination activity of lectin was inhibited by d-mannose, d-glucose, and α-methyl-d-mannopyranoside. Thermal treatment at 50–60°C was sufficient to reduce the action of lectin, as well as a pH below and above the 6–7 range. Therefore, the use of P. platycephala meals as a dietary ingredient for tambatinga with no lectin inactivation is not recommended as it can negatively affect the fish’s biochemical parameters and growth. Acid or alkaline solutions can be an alternative for inactivating the protein and improving its use by fish and other animals.