Evaluation of Soy Protein Concentrate as a Substitute for Fish Meal in Diets of Juvenile Miragaia (Pogonias courbina)
Author: Anne Karolayne dos Santos Ferreira Gomes (Currículo Lattes)
Advisor: Dr. Marcelo Borges Tesser
Abstract
Fishmeal (FM) plays a crucial role in the nutrition of aquatic organisms, serving as a traditional protein source. However, excessive use results in pressure on fishing, highlighting the need for sustainable alternatives, such as the utilization of plant-based proteins. This study aimed to evaluate the increasing dietary replacement of fishmeal by soy protein concentrate (SPC) in juvenile miragaia, at five levels: 0% (S0), 25% (S25), 50% (S50), 75% (S75), 100% (S100). The fish (11.58 ± 0.83 g) were housed in 15 tanks (volume of 300 L; 12 fish/tank) and fed three times a day until apparent satiety for 60 days. Zootechnical performance, plasma biochemical indices, intestinal, and liver morphology were analyzed. Fish fed diets containing partial replacement (up to 50%) of FM by SPC showed similar results to the control group (S0). Fish fed S100 showed a reduction in final weight and shortening of intestinal folds, suggesting a decrease in nutrient absorption capacity. Increased infiltration of eosinophilic granule cells (EGCs) suggests an inflammatory response in the intestine. The fish showed a reduction in transaminase enzymes, indicating possible liver damage resulting from the presence of antinutritional factors (ANFs) present in SPC. Furthermore, the fish presented hepatic steatosis, associated with the presence of ANFs in SPC, such as saponins and lectins. In conclusion, replacing FM with SPC can be done partially, up to 25%, in diets for juvenile miragaia, without compromising their growth and health.