Comparative activities of semicarbazide-sensitive amine oxidase (SSAO) in five domestic species

Semicarbazide-sensitive amine oxidase (SSAO) activity was measured spectrophotometrically using benzylamine as a substrate, in the serum of healthy males and females of horses, camels, cattle, sheep and goats. The animals were born and raised in the same area, and the blood collection was made on the same day to avoid variations. Also the concentrations of protein and copper were measured in the same samples. There were no significant gender-related differences in SSAO activity between the tested animals regardless of species. Activities of SSAO in either male or female of horse were significantly different (p < 0.05) from the remaining tested animals. The highest activities (expressed as micromole of benzaldehyde production/mg protein/hr) were found in horses (9.592 and 9.458), followed by camels (3.226 and 2.407), cattle (1.014 and 1.648), goat (0.750 and 0.572) and sheep (0.435 and 0.244). Insignificant higher activities of SSAO were noted in all males of the tested animals compared to that in females except in cattle. The results suggest that horses are endowed with a very high activity of this enzyme amounting to 3-21 times higher than that found in large and small ruminants. There were no significant differences between the levels of protein and copper in either sex of all the tested species.