Date of Award
Master of Science - Agriculture
After mating, birds have the ability to store semen within the female reproductive tract. The sperm storage tubules will store and subsequently release semen to travel up the oviduct. Sperm cells that make the trek up the oviduct have a chance to fertilize the ovum. These sperm cells will bind to the perivitelline layer of the ovum and hydrolyze a hole in the perivitelline layer, where it has the possibility to fertilize the female sex cell. Analyzing the number of penetration points on the perivitelline layer is an effective way to analyze reproductive efficiency. Many environmental factor has its effect on reproductive efficiency, however, only a few research trials have been done that analyze how environmental variables affect sperm penetration in itself. A population of 120 twelve week old random bred Japanese coturnix quail was separated into breeding ratios of three hens per cock making 30 pens with four birds in each. Treatments of optimal nutrition, suboptimal nutrition, and mild heat stress 75-80°F were utilized. These treatments were compared to a control group, where the males were not removed from the pen after 14 days. Males were left in the breeding pens for 14 days and then taken out, except for the control group where the males resided for the entire duration of the study. Sperm penetration assays were taken and analyzed every other day until no fertile eggs were laid. On every other consecutive day, eggs were collected and set to incubate until hatch. After hatch, percent hatchability was calculated. It was observed according to
Davis’ Correlation coefficients that day of the trial has a substantial negative correlation on sperm penetration and percent hatch by (-0.65871) and (-0.5058) respectfully. Sperm penetration and percent hatch show a very strong positive correlation of (0.76404). This population of quail was observed to store semen in sufficient quantities to maintain at »30 sperm penetration points (SPP) for 3 days before dropping significantly in SPP (p < 0.0001). Where this same population could lay hatchable eggs for 8 days before dropping in hatching percentage, (P < 0.0024). Additionally, it was observed that proper nutrition had a more significantly greater effect by increasing SPP and slightly increasing percent hatch than the effects of heat stress. Overall, it appears that similar trials that observe the longevity of fertility could be used to model the environmental effects on SPP, transversely affecting hatchability.
Ashabranner, Garret G. and Bray, Joey L., "Analyzing the Longevity of Sperm Within the Female Japanese Quail by Assessing Sperm Penetration of the Perivitelline Layer Under Optimal and Suboptimal Conditions." (2020). Electronic Theses and Dissertations. 342.
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