A commonly used rumen-protected conjugated linoleic acid supplement marginally affects fatty acid distribution of body tissues and gene expression of mammary gland in heifers during early lactation

Table 2 Selected milk lipid fatty acids during period 2 (>42 until 105 DIM)

Fatty acid [g/day]	Treatment¹		SEM	P-value
	CON	CLA		Trt	Trt x WL²
4:0	37.3	33.5	1.9	0.186	0.470
6:0	29.8	23.3*	1.6	0.016	0.767
8:0	16.6	11.8*	1.2	0.011	0.824
10:0	41.1	27.5*	3.2	0.015	0.888
12:0	47.1	30.4*	3.8	0.013	0.931
14:0	129	104	8.1	0.059	0.858
c 9-14:1	11.0	6x.9	1.3	0.052	0.977
15:0	14.8	10.2	1.5	0.055	0.430
16:0	364	267*	19.7	0.009	0.346
c 9-16:1	15.2	12.8	1.3	0.240	0.800
17:0	5.8	5.0	0.4	0.182	0.410
18:0	72.3	72.9	4.5	0.927	0.261
t 6/t 7/t 8-18:1	1.2	1.6	0.15	0.075	0.250
t 9-18:1	1.7	2.1	0.14	0.078	0.484
t 10-18:1	2.6	4.3	0.62	0.080	0.708
t 11-18:1	5.0	6.1	0.38	0.073	0.364
t 12-18:1	2.1	2.6	0.20	0.121	0.220
t 13/t 14-18:1	2.5	2.7	0.21	0.590	0.033
c 9-18:1	139	150	8.5	0.375	0.388
c 11-18:1	6.0	6.4	0.67	0.671	0.624
c 12-18:1	1.9	2.4	0.19	0.075	0.253
c 13-18:1	0.7	0.8	0.06	0.664	0.911
18:2 n-6	13.3	14.5	0.97	0.384	0.924
18:3 n-3	0.31	0.24	0.02	0.069	0.253
CLA
c 9,t 11-CLA	3.4	4.3	0.34	0.093	0.767
t 10,c 12-CLA	0.00	0.37*	0.04	0.000	0.030
Other CLA	0.73	0.91	0.07	0.078	0.211
Summations
∑ SFA	781	608*	39.9	0.014	0.582
∑ MUFA	199	208	11.5	0.626	0.444
∑ PUFA	24.5	26.8	1.7	0.374	0.762
∑ trans-18:1	19.7	24.7	1.9	0.103	0.254
∑ BCFA³	17.1	16.0	0.81	0.347	0.346
∑ C16⁴	380	280*	20.9	0.010	0.366
∑ de novo⁵	345	261*	21.4	0.021	0.947
∑ preformed⁶	282	301	13.9	0.358	0.291
Ratio
c 9-14:1/14:0	0.86	0.55	0.10	0.060	1.000

¹Treatment (Trt): cows in the control (CON) group (n = 10) received a control fat supplement, in which the CLA were substituted with stearic acid. Cows in the conjugated linoleic acid (CLA) group (n = 10) consumed 6 g/d each of trans-10,cis-12 CLA and cis-9,trans-11 CLA.
²Week of lactation; ³BCFA branched-chain fatty acids; ⁴C16 Sum of 16:0 and c 9-16:1.
⁵de novo: fatty acids <16 carbon atoms; ⁶preformed: fatty acids >16 carbon atoms.
*Estimated mariginal means (EMMeans) are defined as significant (P < 0.05).

ISSN: 1476-511X