Influence of Phospholipids on Ruminal Fermentation in Vitro and on Nutrient Digestion and Serum Lipids in Sheep

Abstract

Phospholipid supplements were incubated in vitro or fed to sheep to determine how they affected ruminal fermentation, nutrient digestion and serum lipid concentration. In vitro, deoiled soybean lecithin added to hay increased (P less than .05) total VFA concentration but had no effect on fiber digestion in four of five trials. Purified phospholipid (synthetic phosphatidylethanolamine), however, had little effect on in vitro hay fermentation when tested at four levels (0, 10, 20 or 30 mg) in three separate trials. Deoiled soybean lecithin disappeared in vitro at two rates, 12.9 and .66%/h for the fast- and slow-degrading fractions, respectively. Compared with 2.4% corn oil supplements, 5.2% soybean lecithin added to sheep diets (56% concentrate) reduced (P less than .05) energy, fiber and nitrogen digestibilities. Crude lecithin reduced (P less than .05) energy digestibility more than deoiled lecithin. Both types of lecithin increased (P less than .05) serum nonesterified fatty acid concentrations but had no effect on serum glucose, cholesterol or triglyceride concentrations compared with the corn oil diet. In summary, phospholipids had different effects on ruminal fermentation, depending on their source. None had a beneficial effect on fiber digestion. Phospholipids are degraded in the rumen and inhibit digestion in a manner similar to that of the commercial fats and oils.

Effect of lecithins partly replacing rumen-protected fat on fatty acid digestion and composition of cow milk

“…Lecithins are considered to be less susceptible to microbial modification because they are not so easily hydrolysed in the rumen [24] and so might keep their unsaturated characteristics better than oils until reaching the small intestine. Furthermore, lecithins could particularly enhance fatty acid absorption by their dispersing and emulsifying properties.…”

Effects of canola and soya lecithins compared with canola oil and seed on performance, carcass quality and body fat composition of growing bulls

“…Rumen fluid propionate concentration with deoiled soya lecithin (10.7 mmol/1) was, however, even slightly higher than with the canola lecithins. Though not significant, the rumen fluid ammonia concentration showed the same trend towards reduced values with lecithins as had been found in vitro (Wettstein et al, 2000), an effect which might be due to the amphiphatic properties of lecithins (Jenkins et al, 1989). These allow the formation of complexes of lecithin and protein, thus possibly reducing protein degradation in the rumen.…”

“…Such products were shown in vitro to be particularly promising in terms of reduced perturbation of rumen fermentation (Wettstein et al, 2000). Using canola lecithins instead of oil as the only lipid supplement was furthermore found to reduce the in vitro ruminal degradation of feed protein (Wettstein et al, 2000), possibly due to the amphiphatic (i.e., polar -apolar) properties of the lecithins (Jenkins et al, 1989). This might increase the amount of absorbable protein entering the duodenum.…”

“…The FA composition of lecithins is quite variable and substantially differs when the lecithins originate from different plants. Until now, most investigations on lecithins in ruminant nutrition focussed on soya lecithins (e.g., Yoon et al, 1986;Jenkins et al, 1989;Jenkins and Fotouhi, 1990;Lough et al, 1991Lough et al, , 1992. Nowadays, considerable amounts of canola lecithins are also available as potential feedstuffs, but data on the actual feeding value of any type of canola lecithin for growing ruminants are still lacking.…”

“…The term 'lecithins', as used for these by-products, covers complex mixtures mainly of different phospholipids but also of other polar substances and, if not further processed, residual triglycerides (Pardun, 1988). In contrast to oils, lecithins are dispersible in water (Pardun, 1988) and contain a fraction that slowly disappears in the rumen (Jenkins et al, 1989) presumably because different enzymes are necessary to hydrolyze phospholipids and triglycerides (Harfoot, 1981). Consequently, attachment of plant lecithins to feed particles or rumen microbes might be less pronounced than with oils and the release of the fatty acids (FA) could be slower from lecithins, both resulting in less adverse effects on rumen fermentation than with corresponding oils as was shown in vitro (Wettstein et al, 2000).…”