Discriminant Analysis of Sperm Cryotolerance Among Different Breeds of Chickens in Hot Humid Tropical Environment

Abstract

Cryopreservation is a viable reproductive technique but still have detrimental consequences on sperm quality and fertility. This study compared the sperm cryotolerance among different breeds of chickens in hot humid environments. Semen samples were collected from thirty (30) cocks comprising 10 Funaab alpha normal feathers, Arbo acre and dominant black. The semen was analyzed for acrosome integrity, membrane integrity, seminal leukocyte, Live/dead, sperm abnormality, MDA concentration and sperm motility. Breed differences (p < 0.01) were observed in Acrosome integrity, seminal leukocyte, live/dead ratio, sperm abnormal midpiece and sperm abnormal tail. The stepwise discriminant analysis revealed that live/dead, MDA, Abnormal midpiece, Leukocyte, Acrosome, Abnormal head and sperm motility are discriminant variables that can effectively differentiate the three breeds of chickens with Live/dead, MDA and Leukocyte having highly significant (P < 0.0001) discriminatory power. The study obtained two canonical variables accounting for 66.94% and 33.06% of the total variation respectively. The three breeds of chicken were differentiated by linear discriminant functions. 56.67% of Funaab Alpha chicken, 67.78% of Arbo acre and 47.78% of Dominant black chicken were accurately assigned into their breeds while the longest Mahalanobis distance was found between Arbor Acre and Funaab Alpha chicken. The discriminant functions obtained in this study could help differentiate these three breeds of chicken that are suitable for artificial insemination in humid tropics using their post-thaw semen quality.