Novel Calcium Salt Effect of MUFA on Fatty Acid CompositionMonday, April 30, 2012
Calcium salt preparations of dietary cis-monounsaturated fatty acids reduce milk saturated fatty acid concentrations, and increase milk cis- monounsaturated fatty acid concentrations, according to a study by the University of Reading.
A calcium salt (CS) preparation of cis-monounsaturated fatty acids (MUFA) was effective at reducing milk saturated fatty acid (SFA) concentration and increasing beneficial cis-MUFA concentrations, without incurring any negative effects on milk and milk component yields. Some good news from researchers at the University of Reading, who carried out a study to measure the effect of feeding incremental amounts of a novel calcium salt (CS) of cis-MUFA on feed intake, milk yield and milk fatty acid composition of dairy cows.
“We also found that the CS reduced milk fat and protein concentrations, together with increases in milk trans fatty acid and other biohydrogenation intermediate concentrations suggesting at least partial dissociation of the CS within the rumen, which isn’t so good,” Kirsty Kliem told delegates at this year’s British Society of Animal Science annual conference.
Research has demonstrated that cardiovascular disease risk factors can be improved by the isoenergetic replacement of SFA with cis-MUFA in the human diet. And studies at the University of Reading have demonstrated that including milled rapeseed in the dairy cow diet can decrease SFA and enhance cis-MUFA concentration in milk fat.
“However, this was accompanied by a significant increase in trans fatty acid concentrations, which are the consequence of rumen biohydrogenation of dietary unsaturated fatty acids. Feeding rumen-protected sources of cis-MUFA such as calcium salts could minimise the appearance of trans-monoenes in milk fat, but results of previous research have been inconsistent, possibly due to dissociation of calcium salts in the rumen,” said Ms Kliem, explaining the rationale behind her team’s work.
Four Holstein Friesian cows were randomly allocated to one of four dietary treatments. These were a control diet (control) containing no supplemental fat, or the same basal diet with a novel CS of cis-MUFA fed at incremental rates of 20, 40 and 60 g/kg diet dry matter (DM; CS2, CS4 and CS6, respectively).
The diet was a TMR comprising 50:50 forage:concentrate (DM basis), and the forage proportion consisting of 75:25 maize silage:grass silage.
DM intakes and milk yields were recorded daily throughout the experiment. Milk composition was analysed during the final three days of each experimental period for fat, protein, lactose and full fatty acid profile.
“And we found that with increasing inclusion of the CS of cis-MUFA, diet nutrient content tended to decrease due to the dilution effect of the supplement,” said Ms Kliem. “Ca-salt supplementation resulted in a linear reduction in DM intake, but no effect was observed on calculated metabolisable energy intake.
“The CS preparation reduced milk SFA concentration and increased cis¬-MUFA concentration, had no effect on milk yield and milk constituent yields, and linearly reduced milk fat and protein concentrations with increasing supplement level,” she added.
Full details: Kliem KE, Reynolds CK, Humphries DJ, Kirkland R and Givens DI: “Incremental effect of a novel calcium salt of cis-monounsaturated fatty acids product on milk fatty acid composition.” Presented to the British Society of Animal Science Annual Conference, April 4 - 5, 2011, University of Nottingham, UK.