The overall objective of this research was to define the cellular basis underlying
heritable subfertility in roosters homozygous for the rose comb allele (R/R). Fertilization
in the hen is preceded by the ascension of motile sperm through the vagina and sperm
sequestration within sperm storage tubules (SST). The objective of the first set of
experiments was to determine if reduced sperm sequestration could account for subfertility.
Sperm sequestration differed between genotypes following intravaginal insemination (p<0.0001). However, sperm sequestration did not differ between genotypes when sperm
were incubated with SST in vitro (p>0.05). Therefore, subfertility was attributed to
reduced sperm transport within the vagina. To test this hypothesis, an assay was developed
to evaluate fowl sperm motility in vitro. Based upon this assay, ejaculates from subfertile
males contained smaller subpopulations of highly motile sperm than the ejaculates from
controls (p<0.001).
The objective of the next set of experiments was to characterize the motility of
individual sperm and to identify a mechanism that could account for the genotypic
difference in sperm cell motility. Computer-assisted sperm motion analysis evaluation
revealed that ejaculates from controls contained 91% motile sperm whereas ejaculates from
subfertile males contained 62% motile sperm (p<0.001). The ATP concentration in sperm
from subfertile males was 63% less than that of sperm from controls (p<0.001). A link
between sperm ATP concentration and immotility was investigated. First, sperm
metabolism was evaluated using motility as an endpoint. The genotypic difference in sperm
motility persisted when ATP synthesis was limited to glycolysis (p<0.001). Consequently,
mitochondrial respiration could not account for the genotypic difference in sperm motility.
In contrast, sperm uptake of [1,2-��H] 2-deoxy-D-glucose did differ between genotypes (p<0.001). The activity of key glycolytic enzymes, creatine kinase, and dynein ATPase did
not differ between genotypes (p>0.05). Therefore reduced sperm motility did not appear
to be due to ATP synthesis, allocation of high energy phosphate bonds along the axoneme,
or ATP consumption (p>0.05). In conclusion, subfertility of roosters homozygous for the
rose comb allele was attributed to decreased spermatozoal glucose transport. / Graduation date: 1997
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/34390 |
| Date | 08 May 1997 |
| Creators | McLean, Derek J. |
| Contributors | Froman, David P. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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