Successive seminal collections from Piaractus mesopotamicus in biofloc technology during the reproductive period

This study aimed to evaluate the sperm characteristics of pacu (Piaractus mesopotamicus) maintained in biofloc technology (BFT) in comparison partial water renewal system (PWR). Twenty-five males in two production systems were used: 12 in BFT and 13 in PWR. The fish were induced to reproduce in two moments: before the distribution in the experimental units of both systems; and after maintenance of the breeders for 42 days in the systems. After 42 days, only 23 % of PWR fish released semen, compared to 75 % of those kept in BFT. This improvement in the reproduction of pacu broodstock kept in BFT can be corroborated by the higher (P < 0.05) gonadosomatic index of broodstock kept in BFT (0.387) compared to those kept in PWR (0.135), and also due to more advanced germ cell stages (spermatocytes, spermatids, spermatozoa) in broodstock testes maintained in BFT at 42 days. Despite a decrease in sperm concentration in BFT from the first to the second collection, the total number of spermatozoa did not differ significantly. Plasma membrane integrity associated with mitochondrial potential was worse for broodstock kept in PWR compared to those kept in BFT. The total amount of spermatozoa produced per liter of water used in BFT was 46,406, surpassing 304 of PWR's system. Maintaining pacu breeders in BFT for 42 days is more efficient for induced reproduction in situations of successive semen collections compared to the PWR system, with improved water optimization.