Effects of Feeding an Omega-3 Rich Supplement on the Fatty Acid Composition and Motion Characteristics of Stallion Spermatozoa
Source: M. A. Harris, C. R. Anderson, S. K. Webel, R. Godbee, S. R. Sanders, W. A. Schurg, L. H. Baumgard, and M. J. Arns
Study objectives were to characterize the effects of feeding a protected fatty acid from marine sources (PFA; United Feeds, Inc., Sheridan, IN, USA) on fatty acid composition of stallion spermatozoa and to relate changes in fatty acid profiles to semen characteristics. Six stallions were paired by semen characteristics and allocated to one of two diets (three stallions per diet). The diets fed for 90 d, consisted of a basal diet that was either unsupplemented (n=3) or supplemented (n=3) with 550g/d PFA containing 29.1 g/d of long chain n-3 PUFA. Blood samples were harvested via jugular venipuncture on d 0, 19, 30, 45, 60, 75, and 90 and total plasma lipids analyzed for fatty acid composition. Seminal fluid and spermatozoa samples were collected on the same days as blood and analyzed for fatty acid composition and spermatozoal parameters (motility and viability). Prior to diet initiation and following 90 d supplementation, ejaculates were collected and processed by industry standard procedures for cold-storage (24 and 48 h) and cryopreservation. Data were analyzed as a repeated measures design using PROC MIXED procedure of SAS. Lipid plasma concentrations of long chain n-3 PUFA in PFA-supplemented animals increased (P < .05) by d 19 and increased (P < .05) further on d 30 and remained elevated (P<.05) through d 90. Protected fatty acid supplementation resulted in increased (46%; P < .05) daily spermatozoa output (DSO), whereas control stallion DSO did not change. There was a stallion x treatment x day interaction for spermatozoa membrane fatty acid composition. The proportion of sperm membrane long chain n-3 PUFA increased over 90 d of supplementation and was tightly dependent on day and stallion. Despite changes in fatty acid profiles, sperm motion characteristics did not differ. The number of motile sperm was similar following cold-storage and cryopreservation from stallions fed either PFA-supplemented or control diets. Data suggests supplementing a PFA can be used to manipulate sperm membrane lipid composition, however the effect on spermatozoal function remains unclear.
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