Vpliv oksidativnega, metabolnega in vročinskega stresa na reprodukcijske parametre goveda

Šmigoc, Jernej (author), Mrkun, Janko (mentor)

Namen doktorske naloge je bil preveriti, ali bo imelo preventivno dodajanje vitaminov AD3E oz. kombinacije vitamina E (vit. E) in selena (Se) kravam molznicam v obporodnem obdobju pozitivne učinke na zmanjševanje metabolnega, oksidativnega in vročinskega stresa ter njegovih posledic na zdravje in reprodukcijske parametre. Določili smo koncentracijo vit. E in Se, aktivnosti superoksid dismutaze (SOD) in glutation peroksidaze (GPX) ter vrednosti skupne antioksidativne kapacitete (TAS), neesterificiranih maščobnih kislin (NEFA) in beta-hidroksibutirata (BHB) v krvni plazmi pri tretirani skupini molznic (N=16) in kontrolni skupini (N=18) v štirih zaporednih merjenjih v razponu od enega tedna pred porodom do štirih tednov po porodu. Rezultati kažejo, da je bil dodatek vit. E in Se za krave ob porodu učinkovit, saj smo v tretirani skupini zabeležili vzdrževanje želene ravni vitaminov v času telitve ter zmanjšanje upada v začetku laktacije. Pri kontrolni skupini smo z napredovanjem laktacije opazili postopno upadanje antioksidativne aktivnosti oz. parametra TAS; pri tretirani skupini upad ni bil tako izrazit. Dodajanje Se in vit. E je povečalo učinkovitost odziva antioksidativne zaščite; aktivnost encimov SOD in GPX se je v tretirani skupini v preiskovanem obdobju postopoma povečevala. Najvišjo povprečno vsebnost NEFA in BHB v krvni plazmi smo v obeh skupinah zabeležili dva tedna po porodu, vendar je bila pri tretirani skupini koncentracija NEFA in BHB pomembno nižja. Pri tretirani skupini molznic smo po porodu diagnosticirali pomembno manj primerov zaostale posteljice, endometritisa in ovarialnih cist; čas, potreben za involucijo maternice, je bil pomembno krajši; boljša je bila uspešnosti prve osemenitve ter dolžina servisnega intervala. V drugem delu raziskave smo nadalje preverjali, ali se preventivno dodajanje vit. E in Se povezuje tudi z uspešnostjo embriotransferja pri kravah. Primerjava števila uspelih implantacij zarodkov med kontrolno in tretirano skupino kaže v prid slednje, saj je v tej skupini 64,7 % telic ostalo brejih po transferu zarodka ter donosilo zdrava teleta. V kontrolni skupini je bila implantacija uspešna v 41,2 %. V raziskavi smo uspeli dokazati, da lahko s preventivnimi ukrepi blažimo učinke oksidativnega stresa in krepimo sposobnost organizma za boljše odstranjevanje reaktivnih kisikovih zvrsti (ROS) in izboljšujemo energijski status goveda.

• Language: Slovenian
• Keywords: reprodukcija, oksidativni stres – učinki zdravil, toplotni stres – učinki zdravil, metabolni stres – učinki zdravil, vitamin E – farmakologija – terapevtska raba – kri, selen – farmakologija – terapevtska raba – kri, antioksidanti – metabolizem
• Work type: Doctoral dissertation
• Organization: VF - Veterinary Faculty
• Year: 2023
• PID: 20.500.12556/RUL-152992
• Publication date in RUL: 14.12.2023

Secondary language

• Language: English
• Title: The impact of oxidative, metabolic and heat stress on reproductive parameters of cattle

Abstract

The purpose of the doctoral thesis was to verify whether preventive supplementation of vitamins AD3E or a combination of vitamin E and selenium to dairy cows during the peripartum period would have a positive impact on reducing metabolic, oxidative, and heat stress and its effects on health and reproductive parameters. We determined the concentration of vit. E and Se, SOD and GPX activity and TAS, NEFA in BHB values in blood plasma in the treated group of dairy cows (N=16) and the control group (N=18) in four consecutive measurements, ranging from one week before parturition to four weeks after parturition. Supplementation of vit. E and Se was effective for cows at parturition since the measurements show that the desired levels of vitamins were maintained during calving and there was a reduction of decline at the beginning of lactation. In the case of the control group, the progressive deterioration of the antioxidant activity, or the TAS parameter, was observed with the development of lactation. Supplementation of Se and vit. E. increased the efficiency of the antioxidant protection response, and the activity of SOD and GPX enzymes gradually increased in the treated group throughout the monitored period. The highest average content of NEFA and BHB in blood plasma was recorded in both groups two weeks after delivery. However, the concentration of NEFA and BHB was significantly lower in the treated group. In the treated group of dairy cows, significantly fewer cases of retained placenta, endometritis, and ovarian cysts were diagnosed after delivery. The required time for uterine involution was significantly shorter in the treated group. There was also a difference in the success rate of the initial insemination and the length of the service interval. In the second part of the research, we further examined whether the preventive supplementation of vit. E and Se can also be associated with the success rate of embryo transfer in cows. The number of successful embryo implantations was higher in the treated group. In this group, 64.7% of heifers remained pregnant and gave birth to healthy calves. In the control group, the implantation success rate was 41.2%. In our study, we were able to demonstrate that preventive measures can hinder the effects of oxidative stress and strengthen the ability of the organism to remove ROS and improve the energy status of cattle better.

• Keywords: reproduction, oxidative stress – drug effects, heat stress – drug effects, metabolic stress – drug effects, vitamin E – pharmacology – therapeutic use – blood, selenium – pharmacology – therapeutic use – blood, antioxidants – metabolism