2586 CAROPRESE ET AL.
Table 4. Least squares means ± SEM of desaturase and nutritional indices of milk from cows fed the
experimental diets1
Item
Treatment
CT FO FS SEM Effect, P-value
Desaturase indices2
C14:1 cis-9 0.052 0.053 0.053 0.0018 NS
C16:1 cis-9 0.045 0.047 0.043 0.0023 NS
C18:1 cis-9 0.69a 0.68ab 0.67b 0.0052 NS
Conjugated linoleic acid 0.170c 0.187b 0.294a 0.0043 ***
Nutritional indices3
Atherogenic index 2.119a 2.093b 1.859c 0.62 *
Thrombogenic index 2.50a 2.41ab 2.31b 0.046 *
a–cMeans in the same row with different superscripts differ (P < 0.05).
1CT = control group with no fat supplementation; FO = fat supplementation based on fish oil (Orovital Cod,
Ascor Chimici srl, Capocolle di Bertinoro, Italy); FS = fat supplementation based on flaxseed (Lin Tech,
Tecnozoo srl, Torreselle di Piombino Dese, Italy).
2Desaturase indices are ratio of the Δ9-desaturase product divided by the sum of the Δ9-desaturase product
and substrate as described by Kelsey et al. (2003). For example, the desaturase index for C14:1 cis-9 would be
(C14:1 cis-9)/(C14:1 cis-9 + C14:0).
3Atherogenic and thrombogenic indexes were calculated using Ulbricht and Southgate’s (1991) formulas:
atherogenic index = (C12:0 + 4 × C14:0 + C16:0)/[ Σ monounsaturated fatty acids + Σ polyunsaturated fatty
acids (n-6) + (n-3)]; thrombogenic index = (C14:0 + C16:0 + C18:0)/[5.0 × Σ monounsaturated fatty acids +
0.5 × Σ polyunsaturated fatty acids (n-6) + 3 × Σ polyunsaturated fatty acids (n-3) + (n-3)/(n-6)].
*P < 0.05; ***P < 0.001.