engleski

Study on serum paraoxonase (PON1) and platelet-activating factor acetylhydrolase (PAF-AH) activities in subfertile cows

The aim of the study was to determine the PON1 and PAF-AH activities as well as the related metabolic parameters in the serum of infertile cows in order to get a better insight in the involvement of these enzymes in the fertility of cows. The study was carried out on 46 non-pregnant Holstein-Frisian cows divided into three groups. The first group included clinically healthy cows in the mid-lactation period between 30-60 days (n=16), the second group included clinically healthy cows in the mid-lactation period between 61-120 days (n=11) and third group comprised subfertile cows in the lactation longer than 150 days with repeated unsuccessful artificial insemination (n=19). A statistically significant lower PON1 activity was found in subfertile cows (208 U/L) compared to cows in the period between 30-120 days of lactation (329 U/L). The serum glucose concentration was significantly lower in subfertile cows than in cows during their 61-120 day of lactation, while the total cholesterol and HDL-cholesterol concentrations were significantly higher in subfertile cows (4.4 and 2.7 mmol/L, respectively) than in cows in the lactation between 30 – 60 days (3.5 and 2.3 mmol/L, respectively). However, there was no significant difference in C-reactive protein concentration between the investigated groups. PON1/HDL-cholesterol ratio in subfertile cows (80 U/mmol) was significantly lower compared to cows in the lactation between both 30-60 days (114 U/mmol) and 61-120 days (110 U/mmol). The PAF-AH activity was significantly higher in subfertile cows (233 U/L) than in cows in the lactation between 30-60 days (182 U/L). Our study demonstrates that energy deficit causing reproductive disorders is related to PON1 and PAF-AH activities. A lower PON1 activity in subfertile cows can decrease the antioxidant activity in cows with reproductive disorders, thus making them more susceptible to oxidative stress. Furthermore, a higher PAF-AH activity in subfertile cows indicates a potential involvement of this enzyme in reproduction processes of cows since PAF-AH hydrolyses the platelet-activating factor that plays a crucial role in processes of ovulation, conception and implantation.

paraoxonase; PAF-AH; subfertile cows

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