Assessment of spermatogenesis and plasma sex steroids in a seasonal breeding teleost: a comparative study in an area of influence of a tributary, downstream from a hydroelectric power dam, Brazil.
River damming and building of hydroelectric power plants interrupt the reproductive migration routes and change the major physicochemical parameters of water quality, with drastic consequences for populations of migratory fishes. The goal of this study was to evaluate proliferation and cell death during spermatogenesis and serum profiles of sex steroids in Prochilodus argenteus, from the São Francisco River, downstream from the Três Marias Dam. A total of 257 adult males were caught quarterly during a reproductive cycle in two sites: the first 34 km of the river after the dam (site 1) and the second 34-54 km after the dam (site 2), after the confluence with a tributary, the Abaeté River. Seasonal changes in the testicular activity associated with morphometric analyses of germ cells as well as proliferation and testicular apoptosis support a more active spermatogenesis in fish from site 2, where higher levels of sex steroids and gonadosomatic index (GSI) were also found. In site 1, fish presented low serum levels of testosterone, 17β-estradiol and 17α-hydroxyprogesterone and a low GSI during gonadal maturation. Spermatogonial proliferation (PCNA) and apoptosis (TUNEL) were more elevated in fish from site 1, but spermatocytes were mainly labelled in fish from site 2. Overall, these data demonstrate changes in testicular activity and plasma sex steroids in a neotropical teleost fish living downstream from a hydroelectric dam, supplying new data on fish reproduction in regulated rivers. Moreover, morphometric analyses associated with sex steroids profiles provide reliable tools to assess fish spermatogenesis under environmental stress conditions.
Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), C. P.486, Belo Horizonte, MG, 30161-970, Brasil.
Fabricio F T
FFT
Domingos
Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), C. P.486, Belo Horizonte, MG, 30161-970, Brasil.
Ralph G
RG
Thomé
Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), C. P.486, Belo Horizonte, MG, 30161-970, Brasil.|Programa de Pós-Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais (PUC Minas), Belo Horizonte, MG, Brasil.
Fabio P
FP
Arantes
Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), C. P.486, Belo Horizonte, MG, 30161-970, Brasil.
Antonio Carlos S
ACS
Castro
Estação de Hidrobiologia e Piscicultura de Três Marias, Companhia de Desenvolvimento dos Vales do São Francisco e Parnaíba (CODEVASF), Três Marias, MG, Brasil.
Yoshimi
Y
Sato
Programa de Pós-Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais (PUC Minas), Belo Horizonte, MG, Brasil.
Nilo
N
Bazzoli
Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), C. P.486, Belo Horizonte, MG, 30161-970, Brasil. ictio@icb.ufmg.br.
Elizete
E
Rizzo
D000818:Animals; D001938:Brazil; D004958:Estradiol / Q000097:blood; D005399:Fishes / Q000097:blood / Q000502:physiology*; D006908:Hydroxyprogesterones / Q000097:blood; D008297:Male; D011210:Power Plants; D012098:Reproduction / Q000502:physiology*; D045483:Rivers; D012621:Seasons; D013091:Spermatogenesis / Q000502:physiology*; D013256:Steroids / Q000097:blood*; D013739:Testosterone / Q000097:blood
D006908:Hydroxyprogesterones; D013256:Steroids; D013739:Testosterone; D004958:Estradiol