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 1 Selected milk lipid fatty acids during period 1 (1 until 42 DIM)

Fatty acid [g/day]	Treatment¹		SEM	P-value
	CON	CLA		Trt	Trt x WL²
4:0	37.5	37.0	2.6	0.906	0.528
6:0	27.2	22.9	1.5	0.051	0.496
8:0	15.4	12.1*	0.74	0.005	0.809
10:0	36.9	26.8*	1.6	0.000	0.987
12:0	39.3	27.8*	1.7	0.000	0.926
14:0	11.5	92.4*	4.2	0.005	0.992
c 9-14:1	6.3	4.5*	0.36	0.002	0.561
15:0	12.0	10.1*	0.59	0.035	0.991
16:0	301	237*	11.8	0.001	0.199
c 9-16:1	12.2	12.3	0.84	0.924	0.436
17:0	6.1	6.0	0.35	0.728	0.658
18:0	97.8	92.1	8.4	0.633	0.402
t 6/t 7/t 8-18:1	1.6	2.1	0.17	0.063	0.663
t 9-18:1	2.0	2.3	0.12	0.088	0.414
t 10-18:1	4.2	6.8	1.1	0.096	0.822
t 11-18:1	7.3	8.7	0.77	0.215	0.240
t 12-18:1	2.1	2.6*	0.15	0.030	0.352
t 13/t 14-18:1	2.3	2.6	0.16	0.227	0.993
c 9-18:1	172	183	16.0	0.633	0.336
c 11-18:1	8.1	8.5	0.63	0.602	0.649
c 12-18:1	1.7	2.1*	0.14	0.032	0.605
c 13-18:1	0.91	1.0	0.08	0.662	0.249
18:2 n-6	14	14.8	0.95	0.571	0.016
18:3 n-3	0.23	0.2	0.01	0.104	0.857
CLA
c 9,t 11-CLA	3.5	4.4*	0.30	0.039	0.787
t 10,c 12-CLA	0.01	0.42*	0.02	0.000	0.125
Other CLA	0.74	0.97*	0.07	0.022	0.787
Summations
∑ SFA	708	585*	29.5	0.008	0.617
∑ MUFA	230	246	18.9	0.563	0.394
∑ PUFA	25.3	27.8	1.8	0.335	0.143
∑ trans-18:1	24.3	30.7	2.18	0.054	0.998
∑ BCFA³	16.4	15.7	0.74	0.520	0.567
∑ C16⁴	314	249*	12.4	0.002	0.191
∑ de novo⁵	300	246*	11.7	0.003	0.950
∑ preformed⁶	350	365	28.2	0.716	0.262
Ratio
c 9-14:1/14:0	0.54	0.41*	0.03	0.006	0.434

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