Effect of Season on Semen Quality, Testicular Morphometry, and Sperm Production, Semen Extension and the effect of Artificial Insemination on Guinea Fowl (Numida Meleagris) Reproductive Performance.

Abstract

Guinea fowls are an important poultry species in Ghana. Reproductive performance in the indigenous Guinea fowls has been described as low. The objectives of this study were therefore to investigate the effect of the season of the year on semen quality, testicular morphometry, and sperm production in adult Guinea cocks, the use of saline solutions and coconut water as extenders for storing Guinea Cock semen, and the effect of artificial insemination on Guinea fowl reproductive performance. The experiments were conducted from May 2019 to December 2021. A total of five hundred (500) unsexed day-old keets were purchased from Akate farms. The purchased day-old Guinea keets were brooded and reared at the poultry unit of the university farm. After attaining sexual maturity, these birds served as foundation stock for the study. Forty adult Guinea cocks of the pearl variety were randomly selected from the experimental birds and trained for semen collection. Semen was collected from selected semen donors by the dorso-abdominal massage method, pooled, and evaluated for semen quality parameters. For the second experiment, thirty (30) adult Guinea cocks (GCs) were randomly selected from the experimental birds and housed in five (5) cages. Five (5) GCs were randomly selected during each season of the year, weighed, and then euthanized. The Guinea cock carcasses were anatomically dissected and the left and right testis were harvested and used for determining the testicular morphometric parameters, sperm reserves, and sperm production. For the third experiment, semen was collected once weekly from semen donors. The collected semen was pooled and divided into portions and then diluted with normal saline, dextrose saline, Ringer’s lactate solutions, and coconut water at the ratio of 1:3 v/v and stored at room temperature. Aliquots were taken from the preserved samples at hourly intervals and evaluated for the motility, morphology, and viability of spermatozoa. The fourth experiment investigated the effect of artificial insemination on Guinea fowl reproductive performance. The first treatment group consisted of Guinea fowls (GFs) naturally mated in a ratio of one (1) male to four females (4) in six replicates, while the second and third treatment groups consisted of twenty- four (24) Guinea hens, artificially inseminated with 0.03 ml fresh undiluted GC semen and 0. l ml GC semen diluted with Ringer’s lactate solution. After artificial insemination, eggs were collected from the treatment groups from day two (2) to day seven (7), processed, and then incubated. The eggs were sent for incubation once every week for six consecutive weeks. At the end of incubation, the number of keets hatched per treatment group was counted and the unhatched eggs were broken open to determine infertile eggs and embryonic mortality. The volume of the ejaculate, spermatozoa count per ejaculate, percent morphologically normal spermatozoa, percent dead spermatozoa, and sperm quality factor were significantly (P<0.05) highest in the rainy seasons and lowest in the dry season, while the spermatozoa concentration, percent spermatozoa motility, and morphologically abnormal spermatozoa were similar. The body weight of Guinea cocks, gross testicular morphometric parameters, Johnsen’s score, sperm reserves, and daily sperm production were significantly (P<0.05) higher in the rainy seasons than in the dry season. Coconut water was a more effective extender than Ringer’s lactate, dextrose saline, and normal saline in preserving spermatozoa motility, morphology, and viability in Guinea cock semen stored at room temperature. Artificial insemination significantly improved the fertility (%), fertile hatchability (%), and total hatchability (%) rates compared to natural mating. It is concluded that the season of the year influences semen quality parameters, gross testicular morphometry, sperm reserves, and sperm production. Coconut water can preserve Guinea fowl semen during short- term storage at room temperature. The use of artificial insemination improved reproductive performance in indigenous Guinea fowls.