Original Research
Effects of Omega-3 Long Chain Polyunsaturated Fatty Acid Supplementation on Equine Synovial Fluid Fatty Acid Composition and Prostaglandin E2☆

https://doi.org/10.1016/j.jevs.2014.01.014Get rights and content

Abstract

To determine if supplementation of omega-3 long chain polyunsaturated fatty acid (

-3 LCPUFA) alters synovial fluid fatty acid composition and prostaglandin E2 (PGE2) concentration of mature, healthy horses. Twenty, nonpregnant light breed mares were assigned into one of three daily dietary treatments. Group 1 (MARINE) received 38 g total of the
-3 LCPUFA alpha-linolenic acid (ALA, 2 g), eicosapentaenoic acid (EPA, 7.6 g), and docosahexaenoic acid (DHA, 26.6 g) via a marine-derived supplement; group 2 (FLAX) received 38 g of
-3 ALA via a flaxseed supplement; and group 3 (CONT) did not receive additional
-3 LCPUFA. Blood was taken at baseline, 30, 60, and 90 days of supplementation and plasma separated. After 90 days of supplementation, 3 mL of synovial fluid was obtained through arthrocentesis. Plasma and synovial fluid were analyzed to identify fatty acid profiles and determine PGE2 concentration. MARINE synovial fluid fatty acids contained higher of EPA and DHA compared with the CONT group and higher DHA levels compared with FLAX group. Eicosapentaenoic acid was not detected in synovial fluid from the FLAX group. Prostaglandin E2 did not differ (P > .05) among horses; however, the MARINE group tended (P = .10) to have lower synovial PGE2 concentration compared with CONT horses. The presence of EPA and DHA only in MARINE synovial fluid and plasma suggests that direct supplementation of EPA and DHA is needed to modify fatty acid composition. A tendency for lower synovial PGE2 in healthy horses receiving oral EPA and/or DHA merits further investigation in the
-3 supplementation effect on prostaglandin production.

Introduction

The investigation of dietary long chain polyunsaturated fatty acids (LCPUFA) in nutritional research has grown in popularity, with particular interest in the role of the omega 3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in modifying inflammation. It is well documented that these essential fatty acids offer a variety of health-related benefits such as cardio-protective properties, antithrombosis, and modifying inflammatory responses in multiple species.

Lipid-derived metabolites play valuable roles in the inflammatory process, primarily those derived from the long chain fatty acid arachidonic acid (ARA). Of particular interest are eicosanoids; short-lived, potent signaling biomolecules that are instrumental in regulating a variety of cellular functions during both physiological (normal) and pathophysiological (inflammatory) events. Of these active eicosanoids, prostaglandin E2 (PGE2) plays an important role in the inflammatory response and is exclusively derived from ARA. As part of its inflammatory functions, PGE2 stimulates vasodilation (causing swelling and redness), increased permeability (joint effusion), and a hyperalgesic response; an increase in sensitivity, particularly to pain [1]. Elevated synovial PGE2 concentrations are reflective of an inflammatory state [1] and are regarded as a therapeutic target for alleviating clinical signs of joint disease. Synovial PGE2 levels have been positively correlated to the presence of arthritis in humans [2], degree of lameness in dogs [3], and are considered a good indicator of joint disease in the horse [4].

Dietary supplementation of the omega 3 (

-3) fatty acids, alpha-linolenic acid (ALA), and its long chain fatty acid derivatives, eicosapentanoic acid (EPA) and docosahexenoic acid (DHA) have a potential beneficial therapeutic effect in inflammatory arthritides [5]. Elevating these fatty acids in mammalian diets may alter inflammatory processes in the joint [6], and oral administration of EPA and DHA has been shown to reduce joint tenderness in rheumatoid arthritis patients [7]. Additionally,
-3 fatty acid supplementation has modified the production of inflammatory mediators in arthritic horses [8] and dogs [9]. The application of dietary
-3 fatty acids is often a suggested treatment for rheumatoid arthritis in humans [10]. Research suggests that
-3 LCPUFA supplementation may be more efficacious than other dietary therapies in modifying clinical signs of osteoarthritis in dogs [11]. Several
-3 supplementation studies have been completed in horses; however, little to no information exists regarding oral
-3 supplementation and its influence on fatty acid composition of synovial fluid in the horse. Therefore, the goal of this study was to (1) determine if synovial fluid fatty acid profiles differ among horses receiving varying dietary
-3 LCPUFA compared with a nonsupplemented group and (2) determine if oral supplementation altered synovial PGE2 concentrations under normal, healthy conditions. Our hypothesis was that horses supplemented with
-3 LCPUFA, specifically EPA and DHA would lead to increases in synovial fluid concentration of these fatty acids and will have lower PGE2 levels.

Section snippets

Animals and Dietary Treatments

Twenty, mature, idle, nonpregnant light breed mares with no history of joint disease and free of lameness were selected for trial. Mares were housed in dry lot facilities with no forced exercise and managed under protocols approved by the Colorado State University's Animal Care and Use Committee. For 30 days before beginning the trial period, all mares were fed a basal diet of free-choice alfalfa-grass mix hay. Mares were then blocked by age (average, standard error [SE]: 9 ± 2 years), weight

Feed Intake and Other Biological Samples

Animal body weights, body condition scores, feed intake data, plasma, red blood cell, and muscle cell fatty acid results have been previously reported [12]. Synovial fluid was easily collected from each horse, and arthrocentesis procedures did not result in any animal morbidity. Synovial fluid color, clarity, viscosity, and total protein concentrations (Table 3) were all within normal parameters and did not differ (P > .05) among dietary groups.

Plasma Fatty Acid Composition

Plasma fatty acid incorporation at day 90 of

Discussion and Conclusions

To the best of our knowledge, this is the first report of synovial fluid fatty acid evaluation in the horse after dietary supplementation of

-3 LCPUFAs. A 90-day supplementation of an oral
-3 LCPUFA supplement resulted in differences between dietary treatments for synovial fluid fatty acid composition. Synovial fluid ARA was not different among treatments, despite the diet not containing ARA, may indicate an increased conversion of LA to ARA because of a biological need of that LCPUFA. Higher

Acknowledgments

The authors thank the staff at the Gail Holmes Equine Orthopedic Research Center for their technical assistance with laboratory analysis, the undergraduate student volunteers for assisting with data collection and horse care, and Dr Jim zumBrunnen for his statistical assistance. None of the authors have conflicts of interest related to the manuscript. This is the first author's version of work accepted for partial requirements of a PhD degree at Colorado State University in November 2012.

References (22)

  • S.M. Proudman et al.

    Dietary omega-3 fats for treatment of inflammatory joint disease: efficacy and utility

    Rheum Dis Clin N Am

    (2008)

    • Cited by (0)

    ☆

    This is the first author's version of work accepted for partial requirements of a Ph.D. degree at Colorado State University in November 2012.

    View full text
    Copyright © 2014 Elsevier Inc. All rights reserved.