Abstract :
The purpose of the present trial was to compare the percentages of necrotic and apoptotic
polymorphonuclear leukocytes (PMNL) in goat milk with low and high somatic cell count
(SCC). Twenty eight milk samples were collected from 20 lactating goats, determined to be
negative in bacteriological examination, and divided in three groups, according to their SCC:
samples with SCC lower than 500 × 103 cells/mL; between 500 and 1500 × 103 cells/mL; and
higher than 1500 × 103 cells/mL. SCC was performed in an automatic somatic cell counter.
Apoptosis and necrosis were quantified using dual-color flow cytometry with fluorescein
labeled annexin-V and propidium iodide (PI). Results of the present study showed a significant
positive correlation between the percentage of the viable PMNL and milk SCC (r = 0.495,
P = 0.008), as well as a significant negative correlation between apoptotic PMNL and milk
SCC (r = −0.486, P = 0.009). Results also pointed out lower PMNL viability rates due to higher
apoptosis rates in milk samples with SCC lower than 5 × 105 cells/mL.
