Effect of photoperiod on ovarian maturation in Cheirodon interruptus (Teleostei: Characidae).
Garcia, I. D., Plaul, S. E., Torres, D., Del Fresno, P. S., Miranda, L. A. and Colautti, D. C.
Laboratorio de Ecologia de Peces, Instituto de Limnologia "Dr. Raul A. Ringuelet" - ILPLA/ CONICET-UNLP, Boulevard 120 y 62, 1460, CP 1900, CC 712, La Plata, Buenos Aires, Argentina.
Laboratorio de Histologia y Embriologia Descriptiva, Experimental y Comparada, Facultad de Ciencias Veterinarias - UNLP, Av. 60 y 118, La Plata, Buenos Aires, Argentina.
Ministerio de Agroindustria, Subsecretaria de Pesca y Acuicultura de la Nacion, Direccion de Pesca Continental, Paseo Colon 982, 1073, Buenos Aires, Argentina.
Laboratorio de Ictiofisiologia y Acuicultura, Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico de Chascomus "Dr. Raul Alfonsin" - IIB-INTECH/ CONICET-UNSAM, Intendente Marino, Km 8.200 (B7130IWA), Chascomus, Buenos Aires, Argentina.
Cheirodon interruptus is a ubiquitous small characid that inhabits the Pampean region and commonly used as bait. Its vast market is supplied from the wild population causing a significant environmental impact. In this study, we assess the effect of photoperiod on ovarian maturation in order to evaluate its potential as a tool to manipulate reproduction under artificial conditions. Four treatments in triplicate (light: dark, L: D) were tested: 24L: 0D, 12L: 12D, 0L: 24D and a progressive photoperiod corresponding to the daily photoperiod increments in wild during winter-spring transition, accelerated three times. The experiment was conducted for 45 days. Gonadosomatic index (GSI), oocyte mean diameter, vitellogenic oocyte proportions, plasma estradiol concentrations (E2), condition factor (Kn) and standard length were estimated. Values of mean GSI, oocyte diameter, vitellogenic oocyte proportions and E2 concentration were maximum in the progressive treatment indicating vitellogenesis stimulation. In turn the same parameters were minimum in the 24L: 0D, revealing the vitellogenesis inhibition. This study showed that photoperiodic regime play an important role in the onset of ovarian maturation in C. interruptus.
Brazilian Journal of Biology 79(4): 669-677 (2019)