EVALUATION OF DIFFERENT LEVELS OF Moringa oleifera LEAF MEAL TO IMPROVE THE RESPONSE TO STRESS OF WHITE CACHAMA JUVENILE Piaractus brachypomus

The intensification of aquaculture production systems is responsible for the increase in stressful conditions, which induce adaptive responses in fish. These responses are the result of the animal's need to maintain their body homeostasis. However, the maintenance of these long-term responses, mainly due to hormonal action (cortisol) can compromise the fish health status. The aim of this work was to evaluate the effect of dietary supplementation with moringa leaf meal, on some productive and hematological parameters of white cachama juvenile subject to hypoxia. Forty-five white cachama juvenile (132,05 ± 29,48g) were kept in 15 aquariums and fed ad libitum three times a day during 60 days with an isocaloric (4000 Kcal/Kg) and isoproteic (36% protein) experimental diet, composed of five inclusion levels of moringa leaf meal which constituted the following treatments: T1: Control; T2: 10%; T3: 20%; T4: 30% and T5: 40%. Once the feeding phase was finalized, the animals were subject to hypoxia (taken out of the water) during two minutes and returned to water. After one-hour fish were anesthetized with MS-222 (100mg/L) and blood samples were collected by puncture of the caudal vessel with syringes containing heparin, to measure hematocrit, hemoglobin, total protein, glucose, lactate, sodium, chlorine, potassium and cortisol. Additionally, weight gain (WG), specific growth rate (SGR) and hepatosomatic index (HI) were established. The data were subject to an analysis of variance (ANOVA) and the means were compared through the Tukey test (5%). There were no significant differences in WG, SGR, HI, hemoglobin and total protein. Conversely, significant differences were found for hematocrit, cortisol, glucose and lactate, which highest values were found in T1 (table 1), while lower values of these parameters corresponded to T3, T4 and T5. However, T2 and T3 did not show significant differences for cortisol. Animals of T1 showed a decrease of the plasmatic levels of sodium and chlorine and presented significant differences in comparison with the other treatments (table 1). The results suggest that the use of moringa leaf meal can improve the response to stress and maintain the homeostasis of cachama juvenile subject to hypoxia, due to its potent antioxidant effect (high concentrations of phenols and flavonoids) that could enhance the resistance against to unfavorable conditions.