Effect of collection frequency on semen quality and the frequency of abnormal forms of spermatozoa in the emu

Abstract

Animal Production in Australia 1998 Vol. 22 EFFECT OF COLLECTION FREQUENCY ON SEMEN QUALITY AND THE FREQUENCY OF ABNORMAL FORMS OF SPERMATOZOA IN THE EMU I.A. MALECKI A, J.M. CUMMINSB, G.B. MARTINA and D.R. LINDSAY A B A Faculty of Agriculture, The University of Western Australia, Nedlands, WA 6907 Division of Veterinary & Biomedical Science, Murdoch University, Murdoch, WA 6150 The rate of production of spermatozoa and their quality are important indicators of the breeding potential of males. In emus, collection frequency affects the total output of semen and spermatozoa (Malecki et al. 1997b), and this study addresses the effect of collection frequency on sperm quality. Semen was collected by artificial cloaca (Malecki et al. 1997a) from nine emus in two experiments, in a Latin square design, every fourth day, every second day, or daily (Experiment 1), and daily, twice daily and three times per day (Experiment 2). Semen quality was evaluated by counting the number of live and abnormal spermatozoa using nigrosine-eosin preparations (Lake and Stewart 1978). Spermatozoa were counted in three random fields of each slide (100 sperm per field). The percentages of live, dead, normal and abnormal spermatozoa were calculated. Within experiments, collection frequency did not affect the frequency of live and normal sperm (Table 1). The number of live sperm was higher (P<0.05) in Experiment 2 than in Experiment 1. Table 1. Mean (� s.e.), range and coef ficient of variation (c.v. %) of live/dead, normal/abnormal and occurrence of abnormal spermatozoa in emus Forms of spermatozoa (%) Live Experiment 1 Mean 85.1 � 1.1 Range 73 - 95 c.v. 6 Experiment 2 Mean 90.0 � 0.6 Range 84 - 95 c.v. 3 Dead 14.9 � 1.1 6 - 27 36 10.0 � 0.6 5 - 16 30 Normal 98.1 � 0.2 96 - 99 1 97.4 � 0.2 95 - 99 1 Abnormal 1.9 � 0.2 1-4 46 2.6 � 0.2 1-5 38 Bent 8.6 � 1.4 0 - 30 82 Type of abnormality (% of total abnormal cells) Giant 37.5 � 2.9 8 - 71 40 Broken 9.0 � 2.5 0 - 67 142 0.2 � 0.1 0-2 289 Droplet 39.7 � 3.1 0 - 67 40 24.6 � 2.1 5 - 44 44 Distorted 5.2 � 1.5 0 - 25 143 8.0 � 1.3 0 - 24 84 22.2 �2.6 44.7 � 2.3 3 - 47 22 - 71 61 26 Emu semen is characterised by a high number of live and normal spermatozoa. Increasing the frequency of collection yields greater numbers of live spermatozoa but does not affect their morphology. The low numbers of live sperm in Experiment 1 may have been due to longer rest periods between ejaculations, as avian spermatozoa age in the testis and the excurrent ducts (Lake 1981). Low numbers of abnormal spermatozoa cannot rule out their interference with fertility. Giant (presumably diploid) sperm in mammals are thought to be responsible for embryo death through triploidy but can still compete for fertilisation (Mortimer 1977). The cytoplasmic droplets, recently reported in the ostrich (Soley et al. 1996), could indicate delayed maturation (Lin and Jones 1993), but whether their occurrence is related to age, genotype or other factors needs to be further investigated. The quality of artificially collected semen from emus appears to compare well with that from domestic birds and therefore should be suitable for artificial insemination. LAKE, P.E. and STEWART, J.M. (1978). Artificial Insemination in Poultry, Ministry of Agriculture Fisheries and Food, Bulletin 213. (Her Majestys Stationery Office: London). LAKE, P.E. (1981). In Form and Function in Birds, Vol. 2. (Eds A.S. King and J. McLelland) pp. 1-61. (Academic Press: London). LIN, M. and JONES, R.C. (1993). J. Anat. 183, 525-35. MALECKI, I.A., MARTIN, G.B. and LINDSAY, D.R. (1997a). Poultry Sci. 76, 615-21. MALECKI, I.A., MARTIN, G.B. and LINDSAY, D.R. (1997b). Poultry Sci. 76, 622-6. MORTIMER, D. (1977). J. Reprod. Fert. 51, 99-104. SOLEY, J.T., BERTSCHINGER, H.J., ELS, H.J. and BURGER, W.P. (1996). In Improving our understanding of ratites in a farming environment. (Ed D.C. Deeming) pp. 16-18. (Ratite Conference: Oxford). 406