title: Influence of ejaculation frequency on semen characteristics in chimpanzees (Pan troglodytes).
abstract: Semen samples were obtained by masturbation from 6 chimpanzees and the spontaneously liquefied fraction and the remaining coagulum were studied separately. When semen was collected once or twice a week, large intra-individual variations were observed for all measures. The liquefied fraction represented 26.5 +/- 3.2% (weighted mean +/- s.d.) of the total ejaculate but contained 51.3 +/- 3.8% of all emitted spermatozoa. Fructose concentration was higher in the coagulum than in the liquefied fraction (29.3 +/- 3.0 mumol/ml vs 12.0 +/- 2.7 mumol/ml, P less than 0.001) whereas acid phosphatase was less concentrated in the coagulum than in the liquefied fraction (3.5 +/- 0.3 x 10(3) IU/ml vs 13.0 +/- 0.9 x 10(3) IU/ml, P less than 0.001). L-Carnitine and citrate concentrations did not differ between the two fractions of the ejaculate. When semen collection was repeated every hour for 5 h, the ejaculate volume increased from 2.6 +/- 0.7 to 4.7 +/- 0.6 ml (P less than 0.001), whereas total sperm count decreased from 1278 +/- 872 x 10(6) to 587 +/- 329 x 10(6) (P less than 0.05) between the 1st and the 6th ejaculate. In the spontaneously liquefied fraction, the sperm count decreased from 984 to 369 x 10(6). The 6 successive ejaculates gave a total of 20.2 +/- 7.6 ml and 4278 +/- 2884 x 10(6) spermatozoa. The increase of the ejaculate volume was essentially due to an increase of the volume of the coagulum which closely correlated with total amount of fructose (from seminal vesicles) (r = 0.913, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Centre International de Recherches Médicales de Franceville, Gabon, France.
authors.forename: J
authors.initials: J
authors.lastname: Marson
authors.forename: D
authors.initials: D
authors.lastname: Gervais
authors.forename: S
authors.initials: S
authors.lastname: Meuris
authors.forename: R W
authors.initials: RW
authors.lastname: Cooper
authors.forename: P
authors.initials: P
authors.lastname: Jouannet
mesh_terms: D000818:Animals; D004542:Ejaculation; D008297:Male; D008418:Masturbation; D002679:Pan troglodytes / Q000502:physiology*; D012661:Semen / Q000166:cytology*; D012669:Seminal Vesicles / Q000502:physiology; D013076:Sperm Count