Enhancement of oleic acid and vitamin E concentrations of bovine milk using dietary supplements of whole rapeseed and vitamin E

Abstract

-With the aim of reducing the degree of saturation and increasing the C18:1 cis fatty acid content of milk fat, the effects of feeding high levels of whole cracked rapeseed to dairy cows was investigated together with the effect of increasing dietary intake of vitamin E on the vitamin E content of milk. Using a 3 × 3 factorial design, 90 Holstein dairy cows were fed one of three levels of whole cracked rapeseed (0 (ZR), 134 (MR) and 270 g·kg -1 diet dry matter (DM) (HR)) in combination with one of three intakes of supplementary vitamin E (0 (ZE), 2 (ME) and 4 g·cow -1 ·d -1 (HE)). Supplementing with up to almost 2 kg·d -1 of rapeseed oil (diet HR) significantly (P < 0.001) increased C18:1cis in milk fat, from 181 (ZR) to over 400 g·kg -1 (HR) of total milk fatty acids. Concentrations of C18:0, C18:2 and C18:3 fatty acids were also increased (P < 0.001) but by a much lesser degree, and the saturated fatty acids C4:0 to C16:0 decreased substantially. Vitamin E supplementation increased (P < 0.01) milk vitamin E concentrations from 1.29 (ZE) to 1.68 mg·kg -1 whole milk (HE). Thus substantial changes in milk fat composition with potentially beneficial effects on human health were achieved and without any adverse effects on milk taste. However, these improvements must be offset against the substantial reductions (P < 0.001) observed in voluntary feed DM consumption (ZR, 20.6; HR, 15.2 kg DM·d -1 ), milk yield (ZR, 22.9; HR, 13.2 kg·d -1 ) and milk fat concentration (ZR, 42.1; HR, 33.4 g·kg -1 ) which would not be commercially sustainable unless a considerable premium was paid for this modified milk. It seems likely that the optimum dose of dietary rapeseed is lower than used in this study. Résumé -Augmentation de la concentration en acide oléique et en vitamine E du lait de bovin en incorporant dans la ration des graines de colza entières et de la vitamine E. Afin de réduire le degré de saturation des acides gras et d'augmenter la teneur en C18:1 cis du lait, les effets d'une alimentation avec des niveaux élevés de graines de colza concassées entières ont été étudiés chez des vaches laitières, en relation avec les effets de l'augmentation de l'ingestion de la vitamine E sur la teneur en vitamine E du lait. Au total, 90 vaches laitières de race Holstein ont été alimentées selon un schéma factoriel 3 × 3 avec trois niveaux de graines de colza concassées (0 (ZR), 134 (MR) et 270 g·kg -1 de matière sèche (HR)) et trois teneurs en vitamine E (0 (ZE), 2 (ME) et 4 g·vache -1 ·j -1 (HE)). La supplé-mentation avec près de 2 kg·j -1 d'huile de graines de colza (régime HR) a augmenté significativement (P < 0,001) la concentration du C18:1 cis du lait, de 181 (ZR) à plus de 400 g·kg -1 d'acides gras totaux du lait (HR). Les concentrations en C18:0, C18:2 et C18:3 ont été également augmentées (P < 0,001), mais dans des proportions moindres. Dans le même temps, la concentration des acides gras saturés C4:0 à C16:0 a diminué sensiblement. La supplémentation en vitamine E a augmenté les concentrations en vitamine E du lait ...

Changes in fatty acid profile and iodine content in milk as influenced by the inclusion of extruded rapeseed cake in the diet of dairy cows

“…Milk yield in R was significantly decreased in comparison with S. This is in agreement with e.g. Givens et al (2003) or Solomon et al (2000). On the other hand, Kudrna and Marounek (2006) did not find a difference in milk yield between cows receiving rapeseed cake and extruded soybeans.…”

Fatty acid content in milk of dairy cows on a diet with high fat content derived from rapeseed

“…On the other hand, the percentage of nutritionally favourable monounsaturated oleic acid (C18:1; OA) increased (P < 0.05) in milk produced using Energol in the diet in comparison with control milk by more than 10 percentage units in each of the recorded stages of lactation (Table 6). These figures correspond with the data of DePeters et al (2001; increase in OA from 15 to 21 g/100 g of milk fat of dairy cows fed the diet with canola oil) or of Loor et al (2002; increase in OA in a similar experiment with canola oil from 16% to 26%), and data of Givens et al (2003), who found an increase in OA content from 18.1% (control) to 40% of the sum of total determined fatty acids in milk of dairy cows fed the diet with whole cracked rapeseed. Rapeseed oil content in the cow's daily ration was nearly 2 kg in the experiment of Givens et al (2003); however, it was only a half of this amount in the present experiment (0.3 kg from Energol and 0.65 kg from 5 kg of the experimental production mixture).…”

Effect of replacing calcium salts of palm oil distillate with rapeseed oil, milled or whole rapeseeds on milk fatty-acid composition in cows fed maize silage-based diets

“…Replacing CPO with whole and milled rapeseeds (WR and MR) in the diet had little effect on DM intake, but rapeseed oil reduced (P , 0.05) intake. Givens et al (2003) recorded substantial DM intake reductions in cows fed cracked whole rapeseeds, providing greater amounts of rapeseed oil (1.21 kg/cow per day) than in the present study. A lower intake with diets containing rapeseed oil may reflect the negative effects of unsaturated fatty acids on rumen function (Palmquist, 1994), and if so, suggests that both the WR and MR treatments provided some degree of rumen protection to the constituent oil.…”