Summary: | The objective of this research was to clarify the basis
of subfertility in Delaware roosters. It was anticipated
that a sensitive method would be needed to compare seminal
plasma protein composition between subfertile and fertile
roosters. Consequently, the applicability of two-dimensional
electrophoresis was tested as a tool for the
analysis of chicken seminal plasma proteins. Two-dimensional
electrophoresis resolved 95 ± 4.4 derivative
polypeptides from seminal plasma proteins of fertile
roosters, whereas one-dimensional electrophoresis resolved
only 23 ± 0.4. Thus, two-dimensional electrophoresis was
found to be a useful tool for seminal plasma protein
analysis. Seminal plasma composition was compared between
subfertile Delaware and fertile roosters. Seminal plasma
from subfertile roosters was characterized by an imbalance
of proteins, electrolytes, and amino acids (P<0.05).
Neither type of seminal plasma contained proteolytic
activity. No difference (P>0.05) was observed in seminal
plasma osmolality. Differences in seminal plasma
composition were attributed to a dysfunction of the
excurrent ducts of the testis. This realization lead to
experiments designed to modulate subfertility.
Hemicastration exacerbated (P<0.001) subfertility, whereas
supplementation of spermatozoa with seminal plasma proteins
from fertile roosters ameliorated (P<0.001) subfertility.
Addition of seminal plasma proteins from subfertile roosters
to spermatozoa from fertile roosters had no effect (P>0.05)
on fertility. Therefore, subfertility was attributed to
protein deficiency in seminal plasma rather than the
presence of some agent that induces subfertility. The study
of subfertile Delaware roosters has helped establish a link
between seminal plasma proteins and fertility in the
domestic fowl. === Graduation date: 1992
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