3.1. Sperm plasma membrane integrity (PMI,
SYBR-14/propidium iodide assay)
A characteristic dot plot on SCC vs FSC which
classified as sperm are indicated is shown in Fig. 1a,
whereas region of analysis between SYBR-14 versus PI
is depicted in Fig. 1b. The percentage of spermatozoa
with intact plasma membrane (alive, SYBR-14+/PI)
was significantly (P < 0.001) higher in winter (54.6%)
than in the rainy season (43.5%) or summer (46.7%)
(Table 3). The average percentage of moribund
spermatozoa (SYBR-14+/PI+) differed significantly
(P < 0.01) only between winter and summer. Consequently,
the average of dead spermatozoa (SYBR-14/
PI+) was significantly (P < 0.01) lower in winter
(37.5%) than in the rainy season (47.6%) or summer
(43.6%). The average percentage of PMI (SYBR-14+/
PI) and dead spermatozoa (SYBR-14/PI+) was
affected by the year of semen collection/processing
(P < 0.01).