Comparative study on ultrastructure and motility parameters of spermatozoa of tetraploid and hexaploid Siberian sturgeon Acipenser baerii

Abstract

Siberian sturgeon Acipenser baerii is supposed to by species of functionally tetraploidy (4n). Large-scale screening of ploidy levels of various sturgeon stocks revealed one hexaploid (6n) male specimen producing triploid spermatozoa. Spermatozoa of three tetraploid individuals were compared with those of the hexaploid specimen in terms of ultrastructure and motility features. All evaluated morphometrical characteristics of the acrosome, the head, the midpiece and the flagellum showed significantly higher values in spermatozoa of 6n in comparison with 4n Siberian sturgeon males. Mean values of velocities at the beginning of activation differed highly significant between spermatozoa of 6n (155.19 and 158.22 lm s )1 ) and 4n males (181.05 and 179.21 lm s )1 ) in time 15 and 30 s post activation. Nevertheless their velocities did not show significant differences between spermatozoa of 6n (149.35 and 154.16 lm s )1 ) and 4n (158.00 and 152.66 lm s )1 ) in 30 and 45 s post activation. It was supposed that the bigger head of 6n male spermatozoa inhibited motility at the beginning of activation, but later the longer flagellum and bigger midpiece with higher number of mitochondria can partially balance the increased sizes of heads in spermatozoa movement of male with higher ploidy level.

Fertility of a spontaneous hexaploid male Siberian sturgeon, Acipenser baerii

“…High rates of spermatozoa motility indicated high quality of sperm and corresponded with high viability. The initiation of spermatozoa velocity (in 15 sec) of the hexaploid A. baerii was lower than reported for males of normal ploidy level, as also observed by Pšenička et al [42]. The authors considered the higher relative DNA content and larger size of heads of the hexaploid A. baerii spermatozoa to be the cause of the difference.…”

Comparison of spermatozoa parameters, fine structures, and energy‐related factors among tetraploid, hyper‐tetraploid, and hyper‐triploid loaches (Misgurnus anguillicaudatus)

“…Spermatozoa produced by tetraploid male oysters (Dong et al, ) and mussels (Komaru et al, ) have been shown to possess more mitochondria than those produced by diploid males. Presence of higher numbers of mitochondria was reported in spermatozoa of hexaploid male Siberian sturgeon Acipenser baeri compared with tetraploid males (Pšenička et al, ). Our previous work also reported a significantly higher mitochondrial mass per cell and ATP content in diploid sperms of neo‐tetraploid male loaches (Zhao et al, ).…”

Retracted : Study of testis histology and sperm morphology in the Bunnei, Barbus sharpeyi (Gunther, 1874) induced by luteinizing hormone-releasing hormone analogue and carp pituitary extract

“…Pooled‐sperm samples ( n = 20 sperm cells) were used for the study of the morphology of spermatozoa from B. sharpeyi . Semen samples were fixed in a combination (1:1) of 2.5% glutaraldehyde and 0.2 N cacodylate buffer at pH 7.4 (Psenicka, Kaspar, Rodina, Gela, Hulak & Flajshans ). After 2 h of fixation, samples were washed three times for 1 h in fresh 0.2 N cacodylate buffer, then washed repeatedly for 1 h at 4°C in a 1:1 mixture of 1% osmium tetroxide (Gopalakrishnan, Ponniah & Lal ; Alavi et al .…”