Social dominance does not affect semen quality in African wild dogs (Lycaon pictus)

Van den Berghe, F., Paris, M.C.J., Sarnyai, Z., Briggs, M.B., Millar, R., Ganswindt, A., and Paris, D.B.B.P. (2018) Social dominance does not affect semen quality in African wild dogs (Lycaon pictus). Reproduction, Fertility and Development, 30 (1). 97. p. 188.

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Abstract

Sperm banking and artificial insemination could benefit conservation of endangered African wild dogs (AWD). However, it is not clear whether their strict dominance hierarchy causes subfertility in subdominant males that typically do not breed. Our study investigated the effect of dominance on male reproductive parameters including: faecal glucocorticoids (fGCMs) and androgens (fAMs), testis and prostate volume, preputial gland size, semen collection success, and the number, motility, morphology, viability, acrosome integrity (PSA-FITC), and DNA integrity (TUNEL) of spermatozoa collected by electroejaculation. Samples were obtained from n=12 captive AWDs (4 US packs) in the pre-breeding season and n=28 captive AWDs (n=11 from 4 US packs; n=17 from 3 Namibian packs) in the breeding season. Male hierarchy was clearly determined by behavioural observations in all but 1 Namibian pack. Data were grouped by dominance status and means compared by ANOVA or t-test. P≤0.05 was significant.

In the pre-breeding season, there was no significant difference in body weight, fGCMs, fAMs, or prostate and testis volume between dominance groups. Semen was successfully collected from all alphas but only half the subdominants; with urine contamination negatively associated with dominance. Sperm quality was low (17.3 ± 10.2% total motility, 12.8 ± 8.5% progressive motility, 27.4 ± 11.5 x 106 ejaculated spermatozoa, 40.6 ± 9.8% normal morphology, 63.1 ± 5.1% viability, 72.6 ± 5.2% acrosome integrity) with no difference observed in any parameter except progressive motility and normal sperm morphology; which were significantly lower in subdominants (27.7 ± 16.8% vs. 0.0 ± 0.0% and 59.8 ± 13.0% vs. 21.4 ± 5.7%). From pre-breeding to breeding season, testis and prostate volume increased significantly; particularly in beta and gamma males respectively. Prostate volume was higher in alpha than beta males (16.0 ± 6.4 cm3 vs. 5.7 ± 1.4 cm3), but testis volume, body weight, fAMs and fGCMs did not differ between dominance groups (12.0 ± 0.9 cm3, 28.5 ± 0.8 kg, 0.51 ± 0.07 µg/g dry weight - DW, 30.6 ± 2.3 ng/g DW). Semen was successfully collected from 75% of males; with reduced urine contamination. Collection success, urine contamination and preputial gland size were not associated with dominance. Sperm quality improved with significantly greater number, viability, and total motility. However, sperm quality did not differ between dominance groups (47.4 ± 6.7% total motility, 30.5 ± 5.8% progressive motility, 32.3 ± 9.2 x 106 ejaculated spermatozoa, 50.9 ± 5.2% normal morphology, 74.4 ± 4.2% viability, 85.6 ± 3.0% acrosome integrity, 99.7 ± 0.1% DNA integrity).

In conclusion, subdominant males are at higher risk of urine contamination and have lower sperm motility and normal morphology when semen is collected in the pre-breeding season. However, their semen is of similar quality to dominant males in the breeding season, indicating that reproductive suppression of subdominant males is only behavioural. Thus, AWD males of all social ranks in the breeding season are suitable candidates for sperm banking.

Item ID: 54249
Item Type: Article (Abstract)
ISSN: 1448-5990
Keywords: artificial insemination, behaviour, cortisol, testosterone, endocrinology, faeces, physiology, semen, sperm, testis, prostate gland
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Presented at the Annual Conference of the International Embryo Technology Society, 13-16 January 2018, Bangkok, Thailand.

A version of this publication was included as Chapter 2 of the following PhD thesis: Van den Berghe, Femke (2018) A conservation management toolkit: developing assisted breeding and behavioural management tools for the African wild dog (Lycaon pictus). PhD thesis, James Cook University, which is available Open Access in ResearchOnline@JCU. Please see the Related URLs for access.

Date Deposited: 17 Jul 2018 03:24
FoR Codes: 06 BIOLOGICAL SCIENCES > 0608 Zoology > 060803 Animal Developmental and Reproductive Biology @ 70%
05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity @ 30%
SEO Codes: 96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960899 Flora, Fauna and Biodiversity of Environments not elsewhere classified @ 50%
97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 25%
97 EXPANDING KNOWLEDGE > 970107 Expanding Knowledge in the Agricultural and Veterinary Sciences @ 25%
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