PSIV-9 Salmate Dha+ Fish Oil Supplement Fed to Boars and Impact on Sperm Production and Spermatogenesis

Abstract

Abstract Previous studies have found omega-3 fatty acid supplementation increased sperm production in boars, but the mechanism has not been demonstrated. The current study was undertaken to determine if the increase in sperm production was due to a reduction in germ cell apoptosis during spermatogenesis. Mature Duroc boars (438 to 686 days of age) were fed either a control diet of corn, soybean meal, 5% fiber, plus vitamins and minerals per NRC requirements or the control diet plus a proprietary blend of fish oil, Salmate DHA+ supplemented diet with 1.83 gm DHA (Docosahexaenoic Acid, c22:6 omega3) from 26 gm Salmate DHA+ (The Ballard Group, Inc. and Feedworks USA, LTD.) ∙animal-1∙day-1 added to the control diet. The control diet was fed to all boars (n = 10) for 62 days and then Salmate DHA+ was added to the diet of 5 of the boars while the other 5 continued the control diet for another 62 days. At the end of the experiment all boars were slaughtered, the testes collected, slices removed, fixed with Karnovsky’s fixative, post-fixed with 70% ethanol, embedded with acrylic resin, 2-micron sections taken, and sections stained with Toluidine Blue. During the control and Salmate DHA+ feeding, boars were on routine semen collection. The boar stud provided the date of collection, total sperm collected, and age of individual boars. To confirm the impact on sperm production, semen data was evaluated for all boars on the first 62 days of the control diet (before period) and then for control and Salmate DHA+ boars from day 22 to 62 after Salmate DHA+ feeding started (after period). A total of 107 ejaculates were evaluated in the study. Total sperm per ejaculate (X 109) of the control boars was 105.7 ± 7.3 vs. 110.9 ± 10.4 in the before vs. after period (P >0.05). The total sperm per ejaculate (X 109) in the Salmate DHA+ boarswas 103.4 ± 5 vs. 122.8 ± 7 in the before vs. after period (P < 0.05). To examine apoptosis via histology, the number of round spermatids (RS) and Sertoli cells (SC) were counted in 10 stage 1 seminiferous tubules for each boar with adjustments made for cell nucleoli or nuclei size and thickness of the histology section. The ratio of RS/SC or Sertoli Cell Index was then determined to estimate how many RS survived apoptosis in spermatogenesis. The Sertoli Cell index was 9.46 ± 0.84 vs. 15.03 ± 0.97, respectively, for Control and Salmate DHA+ boars (P < 0.01). The number of RS/SC increased 1.59-fold due to Salmate DHA+ treatment and may explain the increased sperm per ejaculate after Salmate DHA+treatment. The exact mechanism of how apoptosis was reduced however awaits further research. Work was supported by The Ballard Group, Inc and Feedworks USA, LTD.