[Enzyme activity of the seminal fluid of bulls after deep freezing and incubation at 39 degrees C]. / Aktivnost na niakoi enzimi v semenna technost ot bik sled dulboko zamraziavane i inkubatsiia pri 39 gradusa C.

The study of bull semen revealed that the activity of alkaline phosphatase in the semen plasma and spermatozoa did not change, however, upon incubation at 39 degrees C for at least 5 hours the activity of the enzyme dropped nearly 10 times. The activity of GOT in both plasma and spermatozoa rose after deep freezing, but the difference recorded were statistically insignificant. Upon incubation of semen at 39 degrees C in the course of five hours the activity of this enzyme decreased, although insignificantly. The differences were likewise insignificant with the drop of GPT following deep freezing. It was concluded that the changes with all three enzymes cannot be used as reliable markers of the injury of spermatozoa following deep freezing.

[Effect of sugars on the biological properties of bull spermatozoa after cryopreservation]. / Vliianie na niakoi zakhari vurkhu biologichnite kachestva na spermatozoidi ot bik sled kriokonservatsiia.

An investigation was carried out on the protective qualities of some type of sugars as ingredients of the g X22l diluent with regard to bull spermatozoa upon freezing after the granule technology. It was ascertained that sugars varied in effect. On the base of the results obtained a new diluent was developed under the conditional name of g X22A, with better cryoprotective qualities than those of the currently used diluents. The optimum effect of semen dilution with the granule technology of freezing of g X22A proved within the range of 1 + 4 to 1 + 8.

[Effect of biologically active substances on the alkaline phosphatase activity, viability and fertility of bull spermatozoa]. / Vliianie na niakoi biologichno aktivni veshtestva vurkhu aktivnostta na alkalnata fosfataza, zhiznesposobnostta i oploditelnata sposobnost na spermatozoidi ot bik.

Studied was the effect of beta-glucuronidase, hydrocortisone, and mercaptoethanol in bull semen on the activity of the alkaline phosphatase and the viability and fertilizing capacity of spermatozoa. It was found that the beta-glucuronidase enzyme in conc. of 270 UI per cu. cm of semen enhanced the activity of one of the forms of AP in agar electrophoresis (AP-1) with the simultaneous enhancement of the thermal resistance of spermatozoa at 46 degrees C and their fertilizing capacity by 9.6 per cent at first insemination. At minimum concentration hydrocortisone (1 X 10(-6) M) lowered the heat resistance of spermatozoa at 39 degrees C. Mercaptoethanol was found to lower by 3 per cent the activity of semen alkaline phosphatase. It is suggested to use the beta-glucuronidase enzyme in the practice of artificial insemination out of all other biologically active agents studied.