Effect of sexual interaction of Jundiá (Rhamdia quelen) on gonadal development and gamete quality
The jundiá (Rhamdia quelen) is a species of siluriform, fresh water, native, with high economic potential, mainly in the southern region. The gonadal development of fish can be influenced, through stimuli by chemical signaling and physical contact between breeders. In captivity, the matrices of non-migratory species are traditionally separated by sex to maintain reproductive control. Jundiá, despite being a lateral migrator, breeders are induced with exogenous hormones in order to enhance captive reproduction. The objective of this work was to analyze the possible effects of the interaction between fish of the same sex and of the opposite sex related to the quality and gonadal development. 129 males (575.50 ± 25.15 g and 38.29 ± 3.59 cm) and 129 females (1035.49 ± 57.37 g and 45.34 ± 2.92 cm) were used,divided into three groups: males and females (MF), only males (M) and only females (F). In males, semen was collected and motility, vigor, mobile cells, spermatocrit and total semen volume were evaluated. In the females, the diameter of the oocyte diameters was collected and measured. The total volume of semen increased in the third collection (October) in group M in relation to MF (10.7 ± 5.6 and 2.37 ± 1.1 mL, respectively). Spermatocrit was higher in the MF group (55.92 ± 9.69%) compared to M (49.30 ± 5.88%) in the third collection. The diameter of the oocytes in the MF group was greater than the M group in the third collection. The rest of the parameters showed no significant difference between treatments. The results demonstrate that the joint maintenance of male and female jundiá, raised in captivity, stimulates the oocyte development, reduces the volume,increases sperm concentration and promotes spontaneous reproductive attitude.