Effects of conjugated linoleic acids (CLA) on tissue response to homeostatic signals and plasma variables associated with lipid metabolism in lactating dairy cows (original) (raw)
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The Journal of nutrition, 2001
Conjugated linoleic acid (CLA) supplements containing a variety of isomers reduce milk fat yield. We have recently identified trans-10, cis-12 CLA as the isomer responsible for inhibiting milk fat synthesis in dairy cows. Our objectives were to determine milk fat yield and fatty acid composition responses to different doses of trans-10, cis-12 CLA. Multiparous Holstein cows (n = 4) were used in a 4 x 4 Latin square design. Treatments consisted of a 5-d abomasal infusion of four doses of trans-10, cis-12 CLA, i.e., 0.0, 3.5, 7.0 and 14.0 g/d. Milk fat yield was decreased 25, 33, and 50%, and milk fat concentration was reduced 24, 37 and 46% when cows received 3.5, 7.0 and 14.0 g/d of trans-10, cis-12 CLA, respectively. Feed intake, milk yield, and milk protein content and yield were unaffected by treatment. Milk fatty acid composition revealed that de novo synthesized fatty acids (short and medium chain) were extensively reduced when cows received the two highest doses, but at the lo...
2021
The aim of the present study was to determine the effect of CLA supplementation on milk yield and composition, blood metabolites and reproductive parameters in dairy cows. Twenty lactating Holstein dairy cows were randomly assigned to one of two dietary treatments: 1) 110 g/day of fat supplement (control) 2) 120 g/day of rumen-protected CLA supplement. The experimental diets were formulated as isocaloric and isonitrogenous. The experimental period started 21 d precalving and continued until 60 day in milk (DIM). Dry matter intake (DMI), body weight (BW) and body condition score (BCS) were not affected by dietary treatments. Supplementation with CLA increased milk yield (3.04 kg/d, P < 0.001) and milk lactose concentration (P < 0.048), but decreased concentration of milk fat (P < 0.001) and short and medium chain fatty acids (P < 0.05). Milk protein concentration, milk energy output and net energy balance were unaffected by CLA supplementation. In cows supplemented with C...
Journal of dairy science, 2006
Trans-10, cis-12 conjugated linoleic acid (CLA) is a potent inhibitor of milk fat synthesis, and the magnitude of milk fat depression is often correlated with the fat content of this isomer. However, the trans-10, cis-12 CLA content does not always correspond to the extent of milk fat depression, and in some instances, an increase in the milk fat content of trans-10, trans-12 CLA has been observed. We synthesized trans-10, trans-12 CLA (>90% purity) and investigated its effect on milk fat synthesis and incorporation into plasma lipids. Three rumen-fistulated Holstein cows were randomly assigned in a 3 x 3 Latin square experiment. Treatments were a 4-d abomasal infusion of 1) ethanol (control), 2) a trans-10, cis-12 CLA supplement (positive control), and 3) a trans-10, trans-12 CLA supplement; 5 g/d of the CLA isomer of interest was provided. Milk yield, dry matter intake, and milk protein were unaffected by treatment. Treatment with trans-10, trans-12 CLA had no effect on milk fa...
Trans-9, cis-11 conjugated linoleic acid reduces milk fat synthesis in lactating dairy cows
Journal of dairy science, 2007
Under certain dietary situations, rumen biohydrogenation results in the production of unique fatty acids that inhibit milk fat synthesis. The first of these to be identified was trans-10, cis-12 conjugated linoleic acid (CLA), but others are postulated to contribute to diet-induced milk fat depression (MFD). Our objective was to examine the potential role of trans-9, cis-11 CLA in the regulation of milk fat. In a preliminary study, we used gas-liquid and high-performance liquid chromatography techniques to examine milk fat samples from a diet-induced MFD study and found that an increase in trans-9, cis-11 CLA corresponded to the decrease in milk fat yield. We investigated this further using a CLA enrichment of 9, 11 isomers to examine the biological effect of trans-9, cis-11 CLA on milk fat synthesis. Four rumen-fistulated Holstein cows were randomly assigned in a 4 x 4 Latin square experiment involving 5-d treatment periods and abomasal infusion of 1) ethanol (control), 2) a 9, 11 ...