The effects of serotonin and of the monoablation of eyestalk on the induction of gonadal development of Penaeus penicillatus (red tail shrimp) were investigated. Immature females with an average weight of 20 g were selected and ramdonly distributed into four groups of 5 animals as follows: initial control group (IC), sacrificed at the 1st day of the experiment; parallel control group (CG), injected with 0.05 ml of saline solution; monoablated group (AG), submitted to monoablation at day 0 and injected with 0.05ml of saline immediatelly after the monoablation and on the 5th day; serotonin group (SG), injected with 0.05 ml of serotonin, dissolved in saline solution, both on day 0 on the 5th day, in a total dose of 15 mug per gram of animal's weight (7,74 x 10 -7 mol). Animals were sacrificed on day 0 for the initial control group (IC), and on the 5th, 10th and 15th days for the other groups. A fragment from the front lobe of the animal's gonad was fixed in aqueous Bouin and processed with the usual optic microscopy techniques. Analyses consisted of a morphological description of cells and measurements of the diameter of oocytes, which gave evidence to the stimulating role of serotonin and of monoablation on gonad maturation. The statistical analysis (Anova -SNK, P < 0.05) of the diameter values of oocytes showed monoablation to be more effective in inducing ovary maturation than serotonin at the concentration used (7,74 x 10-7 mol).
Penaeus sp.; serotonin; 5-HT; reproduction; ovary maturation
