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Vreme oko partusa kod mlečnih krava smatra se najosetljivijim periodom sa više aspekata, među kojima se posebno ističu prestrojavanje metabolizma u pravcu laktacije i posledično povećanje oksidativnog stresa organizma. Osim toga, indukcija porođaja uz pomoć PGF2α dodatno povećava učestalost retencije posteljice. U sistem odbrane od oksidativnog stresa ukljuceni su neenzimski molekuli (vitamini C i E i glutation) i enzimi: superoksid dismutaza, katalaza i glutation peroksidaza. Selenoenzim glutation peroksidaza redukuje nastale hidroperokside masnih kiselina, čime prekida lančanu reakciju oštećenja lipida ćelijske membrane. malondialdehid (MDA), nastao neenzimskim cepanjem lipidnih hidroperoksida, može ukankrsno da se veže za druge biološke molekule, čime dovodi do citotoksičnosti i mutagenosti. Koncentracija MDA u krvnoj plazmi predstavlja dobar indikator stepena oksidativnog oštećenja lipida u organizmu. Cilj našeg rada je bio da ustanovimo promene koncentracije MDA u krvnoj plazmi tokom teljenja i u peripartalnom periodu, 12 sati pre i nakon partusa, kao i uspešnost izbacivanja posteljice kod krava čiji je porođaj indukovan prostaglandinom. Ogled je izvršen na kravama Holštajn-frizijske rase podeljenim u tri grupe: 1) nesumplementirana kontrolna grupa (n=9), 2) grupa tretirana sa 20 ml (n=11) i 3) sa 40 ml (n=13) Promtselena® 30 dana pre partusa. Koncentracija MDA u krvi je određivana spektrofotometrijski. Koncentracije MDA u plazmi krava suplementiranih sa 20 ml Promtselena 12 časova pre porođaja (4,59 ± 1,20), tokom porođaja (4,44 ± 0,68) i 12 časova nakon porođaja (4,67 ± 0,80), bile su značajno niže u odnosu na kontrolnu grupu. Grupa tretirana sa 40 ml Promtselena je od svih posmatranih životinja imala najizrazitije smanjene vrednosti MDA u plazmi 12 sati pre partusa. Tretmani sa 20 ml i 40 ml Promtselena® rezultirali su značajnim smanjenjem učestalosti retencije posteljice (38,2% i 30,8%) u odnosu na netretiranu grupu (66,67%). Možemo zaključiti da aplikacija 20 ml i 40 ml Promtselena 30 dana pre indukcije porođaja rezultira statistički značajnim smanjenjem MDA u plazmi tokom peripartalnog perioda, kao i značajnim smanjenjem učestalosti zaostajanja posteljice. The time close to calving in dairy cows is considered as the most sensitive period from more aspects, among which most relevant are the metabolic shift due to lactation and subsequently increased oxidative stress. Besides, PGF2 induction of delivery additionally increases the incidence of retained placenta. The oxidative stress defense mechanisms consist of nonenzymatic molecules (vitamins C and E, glutathione) and enzymes: superoxide dismutase, catalase and glutathione peroxidase. The selenoenzyme glutathione peroxidase reduces the formed fatty acids hydroperoxides, thus interruptting the chain reaction of damage to the cell membrane lipids. Malondialdehyde (MDA), formed by nonenzymatic fission can cross link to other biological molecules which results in cytotoxicity and mutations. The concentration of MDA in blood plasma is a good indicator of the degree of oxidative damage in the organism. The aim of this study was to determine changes in MDA concentration in the blood plasma during calving and in the peripartal period, 12h before and after calving, as well as the success rate in the expulsion of the placenta in cows with prostaglandin induced delivery. The experiment was done on dairy Holstein Friesian cows allotted into 3 groups: 1) not supplemented control group (n=9), 2) group treated with 20 mL (n=11) and 3) with 40 mL (n=13) Promtselen® 30 days before calving. MDA plasma concentration was measured spectrophotometrically. Plasma MDA concentrations in cows supplemented with 20 mL Promtselen® 12h before calving were (4.59 ± 1.20), at calving (4.44 ± 0.68) and 12h after delivery (4.67 ± 0.80), were significantly lower compared to the control group. The group treated with 40 mL Promtselen® had the lowest MDA results of all groups at 12h after calving. Treatments with 20 mL and 40 mL Promtselen® resulted in a significant decrease in placenta retention (38.2% and 30.8%) compared with the control group (66.67%). It can be concluded that application of 20 and 40 mL Promtselen® 30 days before induction of calving resulted in a statistically significant reduction of plasma MDA concentrations during the peripartal period, as well as with a significant reduction in retained placenta. |
