ACTIVITY OF MALATE-ASPARTATE SHUTTLE ENZYMES OF BULLS AND BOARS REPRODUCTIVE ORGANS AND EPIDIDIMAL SPERMATOZOA

Abstract

The activity of malate-aspartate shuttle enzymes in the reproductive organs and epididimal sperm of bulls and boars was studied.
 The research was conducted on bulls of the Ukrainian black-spotted dairy breed (n = 5; aged 14 - 16 months) and boars of the Great White breed (n = 3; aged 10 - 12 months). After slaughter, the testes and testicular appendages were removed and the spermatozoa were washed with 0.9% sodium chloride solution. Testicular and epididimal tissues were homogenized and centrifuged. Aspartate aminotransferase (AST), malate dehydrogenase (MDG) and protein concentration were determined in the supernatant and epididimal sperm.
 The specie and tissue specificity of aspartate aminotransferase and malate dehydrogenase activity have been established. In particular, in bulls, the activity of AST in the tissues of the testis, head and body of the epididymis of bulls is almost the same (116.5 - 118.3 nmol/min×mg of protein) and on 18.5 - 19.7% (р<0,05) higher in the tail of the appendix. In this case, MDG activity in the reproductive organs shows wavy changes: in the testicular tissue is high (1.96 ± 0.15 nmol / min × mg of protein), and in the epididymis: in the head is reduced (3.5 times ; p <0,001), increased in the body (p <0,05) and decreased again in the tail. In the sperm of bulls, the activity of AST from the head of the appendix - 69.3 ± 8.06 nmol / min × mg of protein, from the body - increased (p <0.05) and again (p <0.001) decreased from the tail of the appendix. MDG activity in sperm from the head of the epididymis was 0.50 ± 0.04 nmol/min×mg of protein, lower by 38.0% (p <0.05) from the body and 50.0% (p <0.001) higher in the tail.
 In boars, the activity of AST in testicular tissue - 20.3 ± 5.22 nmol / min × mg of protein and higher in the appendix: 45.6% - in the head, 59.0% - in the body and 64.0 % - in the tail. Similarly, the activity of MDG in testicular tissue was 0.22 ± 0.02 nmol / min × mg of protein, increases by 40.6% in the head and remained at the same level in the body of the appendix, and in the tail tissue above 2, 5 - 2.7 times (p <0.001). In bovine germ cells, the activity of AST and MDG from the body of the appendix was, respectively, 102.3 ± 6.1 and 13.20 ± 0.15 nmol / min × mg of protein, lowered twice (p <0,001) and 10.7 % in the head and more than four times (p <0,001) and 61,2% (p <0,001) in the tail of the appendix.