Protection of dietary polyunsaturated fatty acids against microbial hydrogenation in ruminants

Abstract

Polyunsaturated fatty acids are normally hydrogenated by microorganisms in the rumen. Because of this hydrogenation ruminant triglycerides contain very low proportions of polyunsaturated fatty acids. A new process is described whereby polyunsaturated oil droplets are protected from ruminal hydrogenation by encapsulation with formaldehyde-treated protein. The formaldehyde-treated protein resists breakdown in the rumen thereby protecting the fatty acids against microbial hydrogenation. When these protected oils are fed to ruminants the formaldehydeprotein complex is hydrolyzed in the acidic conditions of the abomasum and the fatty acids are absorbed from the small intestine. This results in substantial changes in the triglycerides of plasma, milk and depot fats, in which the proportion of polyunsaturated fatty acids is increased from 2-5% to 20-30%. These effects are observed in the plasma and milk within 24-48 hr of feeding while a longer period is necessary to alter the composition of sheep depot fat. The implications of these findings are discussed in relation to human and ruminant nutrition.

Effect of Feefing Protected Lipid on the Uptake of Precursors of Milk Fat by the Bovine Mammary Gland

“…The esterified fatty acid content of each fraction was determined by the method of Stern and Shapiro (1953).…”

“…Following the earlier discovery that formalin treatment prevents microbial degradation of protein in the rumen (Ferguson et al 1967), it has been demonstrated recently that the feeding of large quantities of polyunsaturat ed oil particles coated with formalin-treat ed casein (protected lipid) gives rise to marked increases in the polyunsaturat ed composition of milk (Scott et al 1971). These particles appear to be inert in the rumen and therefore relatively large amounts can be ingested without risk of inducing the ruminal stasis commonly observed when large quantities of unprotected lipid are fed to cows .…”

Effects of Different Fat Sources on Fermentative Characteristics and Microbial Efficiency in the Rumen, and Nutrients Digestibility of Dairy Cows

“…A commercial salt of fatty acids(MEG) was used in the control diet(MEG) to make all diets iso-energetic and iso-oil. Concentration of formaldehyde in whole linseed reached 4% on a protein basis, which meets the minimum recommendation of 2% made by Scott et al(1971). Treatment of linseed was carried out by adding 300g of formalin per kg of whole linseeds to create pH reversible methylene bridges within the seed.…”

“…Reductions have been demonstrated in fibre and organic matter digestion, methanogenesis, ammonia concentrations and acetate:propionate value (Devendra and Lewis, 1974;Palmquist and Jenkins, 1980). Therefore, various methods such as formaldehyde-treated emulsions of fat in proteins (Scott et al, 1971), calcium soaps (Jenkins and Palmquist, 1982), heat treatment (Tice et al, 1994), fatty acyl amides (Fotouhi and Jenkins, 1992), the crystalline hydrogenated fat (Elliott et al, 1994) and feeding whole oilseeds (Scollan et al, 2001) for protecting fat sources from rumen metabolism, which offers the possibility that fat sources fed in such a form may interfere less with rumen metabolism.…”

Long-Term Effects of Feeding Protected Sunflower Seed Supplement on the Composition of Body Fat in Growing Sheep

“…The feeding of polyunsaturated lipid supplements protected from ruminal degradation (Scott et al 1971;Cook et al 1972b) results in ruminant adipose tissue and milk fat containing an increased proportion of polyunsaturated fatty acids particularly linoleic acid but little is known about the effects of prolonged supplementation on such changes or about changes after the supplement has been withdrawn. Accordingly, the present experiment was conducted to monitor changes in total body fat and in the proportion of linoleic acid during and after feeding a polyunsaturated supplement to sheep.…”