Selenium and reproductive function in boars fed a low selenium diet.

Abstract

A study was conducted with 24 crossbred boars (77.5 +/- 2.8 days of age) to determine the effects of low Se status on various spermatozoal characteristics and on Se concentration in semen, serum and primary and accessory reproductive tissues. All boars were fed a low Se diet (cornstarch and Torula yeast) ad libitum. Twelve boars were injected every 14 +/- 1 days with sodium selenite (.33 mg Se/kg body weight) and 12 served as saline-treated controls (low Se status). At 210 +/- 5 days of age, six boars in each group were slaughtered, and serum and various tissues were collected and assayed for Se. Treated boars had higher concentrations of Se in the serum (P less than .001), kidney (P less than .001), liver (P less than .001), heart (P less than .001), skeletal muscle (P less than .01), testis (P less than .01), epididymis (P less than .05), seminal vesicle (P less than .01), bulbourethral gland (P less than .001) and prostate (P less than .001) tissues. Starting at 230 +/- 4 days of age, semen samples were collected from the remaining boars at 4- to 6-day intervals until a total of four ejaculates had been obtained from all but two boars. There were no significant treatment differences in semen volume, percentage normal spermatozoa, percentage viability or spermatozoa concentration/milliliter; however, for combined semen Se data, treated boars had more Se than control boars in the whole semen (.165 vs .07 ppm, respectively), spermatozoa (.418 vs .199 micrograms/10(9) spermatozoa, respectively) and seminal plasma (.03 vs .007 ppm, respectively). The boars were castrated around 250 days of age, and no differences in testis length, diameter, weight and spermatozoal concentration were found between groups. Additionally, there were no apparent differences in daily gain, daily feed consumed and the feed to gain ratio between control and treated boars. Although concentrations of Se in serum, semen and reproductive tissues were much lower in control boars than in treated boars, no apparent impairment of sperm morphology or viability resulted from low Se status.