Evaluation of Mitochondrial Activity and Acrosome Integrity in Black Howler Monkey (Alouatta caraya) Semen
The black howler monkey (Alouatta caraya) is listed as least concern,1 and thus may be used as model for threatened species of the same genus. There are previous reports of semen analysis in Alouatta caraya3,6 but, to our knowledge, evaluation of acrosome integrity and mitochondrial activity has never been reported for this species. Eighteen semen samples were collected by rectal probe electroejaculation6 from six adult captive individuals housed in pairs, trios, or individually. After pH analysis, semen was diluted in Ringer lactate solution6 for other analyses. Results were (mean±SD): volume 69.44±37.52 µl; pH 7.48±0.27; concentration 628.00±614.00x106 spermatozoa/ml; total motility 51±29%; linear progressive motility 39±28%; plasma membrane integrity5,6 45±17%; acrosome integrity (simple acrosome stain)4,5 51±16%; and mitochondrial activity (3,3’ diaminobenzidine stain)2,5 9±8% class I, 52±17% class II, 31±16% class III, 8±7% class IV. ANOVA and Tukey’s test were used to determine whether variables differed between animals and collections. The only significant differences (p<0.05) were semen concentration for animal one was higher than for animals three and five, acrosome integrity in the third collection was higher than first and second, and mitochondrial activity in the first collection was significantly higher than second and third. This report presents new information on semen characteristics of this species which may be used as an aid for further studies on reproductive technologies in this and other neotropical primate species.
The authors would like to thank the São Paulo Research Foundation (FAPESP), the Andrology Lab at the School of Veterinary Medicine and Animal Science, University of São Paulo (FMVZ, USP), and the National Primate Center (CENP), Ministry of Health for their technical and/or financial support.
1. Fernandez-Duque E, Wallace RB, Rylands AB. Alouatta caraya. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. www.iucnredlist.org. Accessed 19 April 2011.
2. Hrudka F. Cytochemical and ultracytochemical demonstration of cytochrome c oxidase in spermatozoa and dynamics of its changes accompanying ageing or induced by stress. Int J Andrology. 1987;10(6):809–828.
3. Moreland RB, Richardson ME, Lamberski N, Long JA. Characterizing the reproductive physiology of the male southern black howler monkey, Alouatta caraya. J Androl. 2001;22(3):395–403.
4. Pope CE, Zhang YZ, Dresser BL. A simple staining method for evaluating acrosomal status of cat spermatozoa. J Zoo Wildl Med. 1991;22(1):87–95.
5. Valle RR, Valle CMR, Nichi M, Muniz JAPC, Nayudu PL, Guimarães MABV. Validation of non-fluorescent methods to reliably detect acrosomal and plasma membrane integrity of common marmoset (Callithrix jacchus) sperm. Theriogenology. 2008;70:115–120.
6. Valle RR, Guimarães MABV, Muniz JAPC, Barnabe RC, Vale WG. Collection and evaluation of semen from captive howler monkeys (Alouatta caraya). Theriogenology. 2004;62:131–138.