The aim of the study was to characterize and evaluate the quality of fresh semen of 4 breeds
of chicken and the susceptibility of cockerel semen to a cryopreservation protocol, assessed
microscopically for sperm motility and morphology and ultimately fertilizing ability
following AI. The differences between breeds were determined by comparing the fertilizing
ability and hatchability of fresh and frozen-thawed semen. The study was carried out at Glen
Agricultural Development Institute and at the University of the Free State. Four chicken
breeds, namely the Rhode Island Red, Potchefstroom Koekoek, New Hampshire and White Leghorn, were used. Qualitative characterization of the semen was performed in 28 cockerels
(7 per breed). Semen was collected using the massage technique twice a week in the first
trial. The eosin-nigrosin staining technique was used to microscopically evaluate the
morphology of the sperm from the different breeds. The fresh semen parameters evaluated
were ejaculate volume, semen colour, semen pH, sperm concentration, the percentage live
and dead sperm, sperm motility and the abnormalities of the sperm. The percentage live and
dead sperm, sperm motility and abnormalities were also evaluated for the frozen-thawed
cockerel semen.
During the second phase of the study, semen was collected 3 times per week from the same
cockerels. Semen was frozen using a fastâfreezing procedure on dry ice, with 10% DMSO as
the cryoprotectant. AI was performed on 4 different breeds of hens (20 hens per breed)
(Rhode Island Red, Potchefstroom Koekoek, New Hampshire and White Leghorn), using
fresh semen (control) and frozen-thawed semen. During AI of each breed, 10 hens were
inseminated with fresh and the remaining 10 hens with frozen-thawed semen.
The sperm characteristics of the semen samples of the 4 breeds recorded were ejaculate
volume, ranging from 0.3±0.1 to 0.4±0.1ml, semen pH of 7.6±0.4 to 7.7±0.3, sperm motility
(scale of 0-5) 2.8±0.8 to 3.1±0.9, estimated sperm motility 58.8±12.5 to 63.8±13.6%,
ejaculate concentration (x109 sperm/ml) of 320.4±286.5 to 748.5±475.3, percentage live
sperm 75.6±29.1 to 81.5±26.8%, and the percentage dead sperm 18.6±26.8 to 24.4±29.1%
respectively, with the percentage normal sperm ranging between 77.3±17.1 and 84.8±9.0%.
Head, mid-piece, tail and other sperm abnormalities of the fresh semen of the 4 breeds ranged
from 2.9±3.3 to 7.7±9.6%, 7.9±5.2 to 11.0±7.0%, 0.4±0.8 to 1.9±3.0% and 0.6±0.9 to
1.5±1.9%, respectively. Semen samples were frozen in pellet form on a block of dry ice, by
pipetting into the indentations on the surface of the ice. The frozen cockerel pellets were thawed following cryopreservation, by being placed into a test tube in a water bath (60°C),
and the tube shaken continuously until complete thawing of the pellet. During the time of
semen cryopreservation, a decrease in the number of live, morphologically normal sperm,
and increase in the percentage dead sperm and sperm with abnormalities were recorded. The
freeze-thawing process caused a significant (P<0.05) decrease in the percentage live sperm
and the sperm motility, ranging between 37.4±10.4 and 42.3±12.1% and 3.6±0.5 and 3.9±0.3
respectively. A consequent increase in the percentage of dead sperm (between 57.7±12.1 and
62.4±10.8%) was also recorded. The sperm abnormalities regarding sperm head
abnormalities ranged between 17.3±3.8 to 22.5±10.3%, the mid-piece abnormalities 7.9±3.8
to 10.4±2.0% and the tail abnormalities between 0.5±0.9 to 2.0±2.4% respectively for the
thawed semen. Frozen-thawed semen was thawed in a water-bath 60°C and hens were
inseminated twice per week using the frozen-thawed semen, and once a week with fresh
semen for a total period of two weeks. Data for the two trials were analyzed using the
ANOVA and the Tukeyâs Studentized Range (HSD) test for repeated measures (SAS system
General Linear Models Procedure).
A total of 973 eggs, from all breeds of chicken namely the Rhode Island Red, Potchefstroom
Koekoek, New Hampshire and White Leghorn were collected following AI with fresh and
frozen semen from individually caged hens. Eggs were collected, incubated and hatched to
check if fertile and normal chicks could be produced from frozen-thawed cockerel semen.
The difference in fertility and hatchability of the hens of the different breeds were compared
and found to be highest in Rhode Island Red, White Leghorn, and Potchefstroom Koekoek
respectively and lowest in New Hampshire using fresh semen. When using frozen-thawed
semen, the sequence of fertility performance was the White Leghorn, Rhode Island Red,
Potchefstroom Koekoek and New Hampshire, respectively. The effect of the numbers of sperm per AI dose on fertility, age at embryonic death, and hatchability of fertile eggs were
also evaluated. Low numbers of sperm per AI in the hens resulted in a decrease in the total
number of chicks hatched. The lowest fertility rate recorded was in the New Hampshire
(2.7%), when using frozen-thawed semen to inseminate the hens. This may be attributed to
the low numbers of sperm inseminated per AI dose. Egg hatchability of the fertile eggs was
high in the White Leghorn (13.6%), Rhode Island Red (12.8 %), Potchefstroom Koekoek (9.7
%) and low in New Hampshire (2.7%) respectively, which could possibly be attributed to the
egg size. Medium sized eggs were preferable for setting, in order to obtain an acceptable
hatch, as they generally hatch better than the larger eggs. The results recorded for fertility and
hatchability in the control group (fresh semen), was similar to the results recorded by other
researchers, showing that the AI method used was acceptable. There still exists a necessity to
develop an ideal cryopreservation method (diluent and freezing procedure), which would
allow for acceptable long term storage of cockerel semen in liquid nitrogen (-196°C) for
future use and export with minimum loss regarding sperm viability and fertilizing capacity.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-09202010-121432 |
| Date | 20 September 2010 |
| Creators | Mosenene, Thatohatsi Madaniel Bernice |
| Contributors | Dr LMJ Schwalbach, Prof JPC Greyling |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-09202010-121432/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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