Cryopreservation of sperm in Brazilian migratory fish conservation

Abstract

Simple, effective protocols for cryopreserving milt of five Brazilian migratory characids (Brycon orbignyanus, Prochilodus lineatus, Piaractus mesopotamicus, Salminus maxillosus and Leporinus elongatus) and one Brazilian migratory catfish (Pseudoplatystoma corruscans) are described. Milt was frozen and stored in dry shippers immediately after collection, making the procedure practical for use in the field. A diluent of 5% glucose, 10% dimethyl sulphoxide and 10% egg yolk was effective for all of the characid species, and a diluent of 10% methanol and 15% powdered milk was effective for P. corruscans. Milt was thawed in an ambient temperature water bath (28–30° C). Activation of thawed milt was effective with either saline (0·9 or 0·45% NaCl) or bicarbonate (1% NaHCO3). Fertilization rates with frozen milt varied between 49 and 300% of the control. Application of the technology for increasing genetic diversity in hatchery programmes for enhancement, mitigation or conservation breeding is discussed, as is its application in aquaculture. Inappropriate use of the technology can threaten wild biodiversity and appropriate legislation and education may be required for its responsible use.

Sucesso do resfriamento e congelamento de sêmen de pirapitinga Brycon nattereri

“…O sêmen de piabanha Brycon insignis foi resfriado com sucesso por até 6 h (Shimoda, 2004), e os de matrinxã Brycon lundii e piracanjuba Brycon orbignyanus por até 14 h (Marques, 2001). Em outro estudo, o sêmen de piracanjuba foi resfriado por até sete dias apresentando taxas de motilidade acima de 37% (Maria et al, 2006 (Carolsfeld et al, 2003;Murgas et al, 2004;Maria et al, 2006) e de piabanha (Shimoda, 2004). Após extensa revisão de literatura, não foi possível encontrar relatos de um protocolo para o congelamento do sêmen de pirapitinga.…”

Cryopreserved sperm for oocyte fertilization of dourado Salminus brasiliensis

“…The control sample of fresh semen was considered 100% and the cryopreserved semen samples were corrected by the control rate (CAROLSFELD et al, 2003).…”

“…The extender solution used was a general formula developed for South American migratory fish, consisting of 10% (15mL) DMSO (dimethylsulfoxide), 5% (7.5g) of glucose, one hen's egg yolk and 135mL of distilled water (CAROLSFELD et al, 2003). The semen and extender solution were mixed at a ratio of one part sperm to four parts extender solution.…”

“…After, the urogenital regions were dried using paper towels, semen was removed by applying abdominal pressure and these samples were subsequently cryopreserved. It was only used sperm that exhibited motility time upper than 40 seconds and more that 80% of motility classified in the score 5 according CAROLSFELD et al (2003).…”

“…indicated that the ideal test for determining the quality of cryopreserved semen was via the egg fertilization rate. According to CAROLSFELD et al (2003), the fertilization rate using cryopreserved semen may vary with the milt volume used, the activating solution and also with the time of contact between the gametes.…”