Effect of passion fruit (Passiflora incarnata L. 1753) on the welfare of the Nile tilapia (Oreochromis niloticus L. 1759) / Efeito do maracujá (Passiflora incarnata L. 1753) sobre o bem-estar da tilápia do Nilo (Oreochromis niloticus L. 1759)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The effects of daily administration of passion fruit (Passiflora incarnata) dry extract, on welfare, social behavior and performance of juvenile Nile tilapia, Oreochromis niloticus were studied. Juvenile males of this species (86.02 ± 5.72g) were maintained under chemical, thermal and visual isolation in glass aquariums (30L) during seven days for acclimatization. Blood samples were collected by puncture of the caudal vein, and used for determination of basal plasma levels of glucose (enzymatic method) and cortisol (immunoenzimatic method). After this period, the fish received commercial ration (32% PB) containing dry extract of passion fruit in sodium alginate (5%) as carrier in doses of 0, 50, 100 and 200 mg/kg, offered twice a day (9:00h and 16:00h) in the proportion of 2% of the biomass. Weekly, the fish were submitted to the reflection of their own image in a mirror for 30 minutes, registering during the first 10 minutes the coloration of the eyes and of the body and agonistic behavior (frequencies of threats, front and lateral confrontations). After 30 minutes they were captured and anesthetized for biometric measures (standard length and weight) for calculation of weight gain, specific growth rate and condition factor, with blood samples collected again for determination of plasma levels of glucose (at 7, 14, 21 and 28 days) and cortisol (at 14 and 28 days). The data of behavior were analyzed by the Kruskal-Wallis non parametric (p=0.05) test and Dunn’s multiple comparison test. The other parameters were submitted to ANOVA, using procmixed of the SAS (p=0.05). No significant differences were observed for the parameters analyzed for any treatment. All the fish grew and, although effects of the different treatments were not detected, cortisol levels reduced and glucose levels increased significantly in relation to basal levels. It is concluded that the fish were maintained under appropriate conditions that preserved their welfare, that the stressor agent and the way it was imposed did not promote social stress, that the passion fruit extract did not contribute to the increase in welfare of the Nile tilapia and that the form of administration did not affect the palatability of the ration nor fish growth. It is suggested, however, that the passion fruit extract interferes in the expression of agonistic behaviors in Nile tilapia.

ASSUNTO(S)

estresse stress welfare oreochromis niloticus palatabilidade passiflora incarnata passiflora incarnata bem-estar palatability oreochromis niloticus

ACESSO AO ARTIGO

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