Comparison of sperm freezability and fertility among Hmong Black-Bone, Barred Plymouth Rock and Thai Native (Pradu Hang Dam) chickens

Abstract

Semen cryopreservation is the most useful method for the long-term storage of chicken genetic resources. The
objective of this study was to compare post- thaw semen quality of Hmong Black- Bone to Barred Plymouth Rock and
Thai native ( Pradu Hang Dam) chickens in terms of sperm motility, viability and fertility. A total of 9 males of each
breed were used; semen collected from each cock was subsequently evaluated under a microscope. Semen samples
were diluted with Schramm diluent, cooled down from 20– 25oC to 5oC and diluent plus DMF ( dimethylformamide)
was added (6% DMF of final volume when the sperm concentration was 1,200 × 106/mL). Semen was loaded into 0.5
mL straws, frozen at -35oC for 12 mins and at -135oC for 5 min in nitrogen vapor, and then plunged into liquid nitrogen.
After thawing the straws in cold water (5oC), sperm motility characteristics were analyzed by computer-assisted sperm
analysis and viability was assessed by staining with SYBR-14 and propidium iodide and observing under a fluorescent
microscope (400×). Fertility tests of frozen semen were carried out by artificial insemination of layer hens. There was
no significant difference in motility and viability between breeds. The fertility rates for frozen semen of Hmong BlackBone, Barred Plymouth Rock and Thai native (Pradu Hang Dam) chickens were 74.96, 69.75 and 80.59%, respectively,
which showed no significant difference between breeds ( P>0. 05) . The results show that semen cryopreservation in
Hmong Black-Bone chickens achieved acceptable freezing ability and fertility for use in ex situ conservation.