PHYSIOLOGICAL RESPONSES OF PACU (Piaractus mesopotamicus), FED CASSAVA (Manihot esculenta) FOLIAGE IN DIETS

Abstract

Brazil is the largest world producer of cassava. Leafs and stem of cassava can be a alternative source of protein for omnivorous fish. However, the potential use is limited by the presence of high level of cyanide acid. The present study evaluated physiological responses of juvenile pacu submitted to increasing levels of the final third of the cassava foliage meal in diets. A completely randomized design was used in factorial scheme 4x2, four levels, 0, 12, 24 and 36 % of cassava foliage meal (CFM), and 2 levels of crude protein (CP), 24 % and 30 %, with three replicates. Three hundred twelve fish (55.33±6.19 g) were distributed into 24 ponds of 13 m2. Results indicated that the levels of CFM inclusion affected the hemoglobin values (P<0.01), as well as the CP level (P<0.05), with interaction of these factors (P<0.01). Significant interaction among the CFM levels and CP was also observed for hematocrit, plasma protein (P<0.01) and plasma lipid (P<0.05). In the 24 % CP level was observed higher values of Hb in control and 36 % of CFM (3.51 g/dl and 3.25 g/dl respectively) while with 30 % CP the control diet and 36 % CFM presented the smallest values (3.29 g/dl and 2.78 g/dl respectively). The higher level of CFM tested, inside of any protein level, had low influence on the pacu metabolism.

KEY WORDS: Cassava leaf and stem fish metabolism, pacu, P. Mesopotamicus.