Elevated seminal plasma protein: a characteristic of Yellow turkey semen

Semen volume, seminal plasma color, protein concentration, and subfractions from 8 white semen (WS) and 8 yellow semen (YS) Large White turkeys were measured for 15 weeks. Average volume was .29 +/- .01 ml for WS and .32 +/- .02 ml for YS males. Plasma from WS was white and averaged 1.84 +/- .07 g/100 ml protein, whereas YS seminal plasma was yellow with 7.03 +/- .5 g/100 ml protein. Protein subfractions in WS and YS seminal plasma were qualitatively similar and consisted of prealbumin, albumin, alpha-1 and -2, beta-1, -2, and -3, and postbeta (gamma). The alpha proteins were more frequently seen in YS seminal plasma. The elevated protein of YS seminal plasma was due to an increased concentration of all proteins, with the possible exception of beta-3, with albumin contributing the most. Except for prealbumin and beta-3, the seminal proteins had the same electrophoretic mobility as counterpart blood proteins. Blood and seminal plasma protein concentrations were poorly correlated (+ .039; P less than or equal to .75). Blood protein concentrations from 68 toms ranged from 3.3 to 5.7 g/100 ml and averaged 4.2 g/100 ml; seminal plasma protein concentrations ranged from .93 to 12.8 g/100 ml. Nineteen percent of the males had YS with seminal plasma protein greater than 4.0 g/100 ml. The high correlation between intensity of the yellow color in YS seminal plasma and protein concentration (+ .76; P less than or equal to .01) indicates that semen quality of turkey breeders could be improved by selection on the basis of low seminal plasma protein concentration.