Efectos de la restricción calórica sobre el inicio de la pubertad y la calidad del esperma en la lubina europea (Dicentrarchus labrax)

Abstract

This study reports the effects induced by a long fasting protocol on the reproductive performance of male sea bass during the first reproductive season. Two different treatments of food deprivation were carried out from July to March, one feed 1/4 and another feed 1/8 of the ration given to the control group (1/4C, 1/8C and C). Both restricted feed regimes resulted in a deep impact over the weight, length and growth rate indexes. Also, the fat visceral index decreased dramatically in November in both feed restricted groups (1/4C and 1/8C). Interestingly, both restricted and controls had similar gonadosomatic index values in November (IGS= 0.4-0.7%). Moreover, the histological analysis revealed the presence of a high number of death cell bodies in testis of those animals kept under both restricted feed regimes. Furthermore, we evaluated the sperm quality along the reproductive season (December-March) and it was shown that a long-term fasting affects sperm quality parameters of pubertal male sea bass such as, density (nº spz cells/ml) and quantity (ml/kg wt), although no differences were observed in motility (µm/seg). Additionally, no statically differences in 11KT plasma levels were observed among experimental groups. Our study evidences that a shortage on energy store is not enough to abolish partially or totally the puberty onset of prepubertal male sea bass.