Table 3. Hotelling’s T-test P-values (above diagonal) and Mahalanobis’s distances (below diagonal) between diets, calculated on the expression of a set of 12 genes selected because differentially expressed in the ANOVA analysis.

	D1	D2	D3	D4
D1	-	0.004	0.004	0.19
D2	3.21	-	0.99	0.01
D3	3.21	0.24	-	0.01
D4	1.45	3.03	2.93	-

D1 = standard diet for growing-finishing pigs; D2 = standard diet supplemented with linseed (source of n-3 PUFA); D3 = standard diet supplemented with linseed, vitamin E and selenium (250 and 0.31 mg per kg of feed respectively; D4 = standard diet supplemented with linseed and plant extracts from grape-skin (3 g per kg of feed) and oregano (2 g per kg of feed) as source of polyphenols (total polyphenols added 37.6 mg per kg of feed).