175 ABSTRACT Original Scientific Article Mac Vet Rev 2016; 39 (2): 175-183 Available online at www.macvetrev.mk Macedonian Veterinary Review The objectives of the present study were to examine the fatty acid (FA) profiles in serum and in the follicular fluid (FF) and the association between polyunsaturated fatty acid level (PUFA) and follicular growth dynamics following induced luteolysis in dairy cows. A total of 29 dairy cows (CL>25mm, follicle≈15mm) at d0 (start of the experiment) were submitted to ultrasound guided transvaginal follicular aspiration for FF collection from the largest follicle and were injected with 500 μg of cloprostenol. The cows were subdivided into Group A1 (n=11) and Group A2 (n=8) resuming follicular growth either from a secondary follicle less than or larger than 8.5mm, respectively, present at the moment of aspiration and Group A0 (n=10) not resuming follicular growth. Follicular development was monitored daily by ultrasonography until the next dominant follicle reached ≈15mm and was subsequently punctured in Group A1 and A2 (d1). Serum and FF samples for FA determination were taken at d0 from all cows and at d1 in Group A1 and A2. No differences were observed between the FA profile in serum nor in FF between sampling days. Regarding the PUFA levels, the serum linoleic acid (C18:2n6) levels at d0 and d1 were significantly higher than in FF, while alpha linolenic acid (C18:3n3) was lower in the serum than in FF, both at d0 and d1. At d0, a tendency for negative correlation between serum and the FF C18:2n6 with subsequent daily follicular growth rate was observed, while, at d1 there was a strong negative correlation between the serum C18:2n6 and daily growth rate (r=-0.71; p=0.0006). The present study revealed similarities of the FA profiles in the serum and in the FF and association between serum and FF PUFA content with the follicular dynamics after induced luteolysis. Key words: polyunsaturated fatty acids, ultrasound guided transvaginal follicular aspiration, cows, follicular growth Corresponding author: Prof. Toni Dovenski, PhD E-mail address: dovenski@fvm.ukim.edu.mk Present address: Institute of Reproduction and Biomedicine, Faculty of Veterinary Medicine, Ss. Cyril and Methodius University in Skopje Lazar Pop Trajkov 5/7, 1000 Skopje, R. of Macedonia Phone: +389 2 3240712 Copyright: © 2016 Atanasov B. This is an open-access article published under the terms of the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Competing Interests: The authors have declared that no competing interests exist. Available Online First: 5 May 2016 Published on: 15 October 2016 http://dx.doi.org/10.1515/macvetrev-2016-0083 INTRODUCTION In the last decades, an intensive genetic selection for higher milk production has inevitably contributed to declining fertility in dairy cows (1). Several studies have shown a strong negative relationship between high milk production and fertility (2, 3) COMPARISON OF PUFA PROFILES IN THE BLOOD AND IN FOLLICULAR FLUID AND ITS ASSOCIATION WITH FOLLICULAR DYNAMICS AFTER PGF 2α INDUCED LUTEOLYSIS IN DAIRY COWS Branko Atanasov 1 , Miel Hostens 2 , Zehra Hajrulai-Musliu 1 , Risto Uzunov 1 , Nikola Adamov 1 , Filip Davkov 3 , Romel Velev 1 , Geert Opsomer 2 , Toni Dovenski 1 1 Faculty of Veterinary Medicine - Skopje, Ss. Cyril and Methodius University in Skopje, R. Macedonia 2 Faculty of Veterinary Medicine – Gent, Gent University, Belgium 3 Dairy farm ZK “Pelagonija”- Bitola, R. Macedonia Received 22 January 2016; Received in revised form 25 April 2016; Accepted 30 April 2016 particularly during the period of negative energy balance. The latter occurs in the early postpartum period due to the incapability of the cows to meet their energy needs (4). Implementation of dietary fats in the daily ration in an effort to ameliorate negative energy balance could increase (at least part of) cow’s energy demands, leading to enhanced reproductive performance (5, 6). However, it was suggested that specific fatty acids (FA), independent of energy status, might be involved and could affect follicle diameter (7) corpus luteum (CL) function (8), oocyte and embryo quality (9), steroidogenesis (10) and prostaglandin synthesis (11). In this respect, the two main families of polyunsaturated fatty acids (PUFA), omega-3 (n-3, linolenic acid, C18:3n3) and omega-6 (n-6, linoleic acid, C18:2n6) were reported to affect fertility (12), although there Brought to you by | Ghent University Library Authenticated Download Date | 3/30/17 4:05 PM