Table 2.

Matrix of the fractional factorial design (2^4-1) for the 4 supplements.

	Basal SFM supplemented with:
SFM	A	B	C	D = ABC
	Phosphatidyl choline (5 mg/l)	Polyamine supplement (1×)	Antioxidant supplement (1×)	Cholesterol (4 mg/l)
#1	-	-	-	-
#2	+	-	-	+
#3	-	+	-	+
#4	+	+	-	-
#5	-	-	+	+
#6	+	-	+	-
#7	-	+	+	-
#8	+	+	+	+

(-) no addition; (+) addition of the indicated amount of additives.