Characterization of 18:1 and 18:2 isomers produced during microbial biohydrogenation of unsaturated fatty acids from canola and soya bean oil in the rumen of lactating cows

Abstract

Ruminal production of biohydrogenation intermediates in response to unsaturated oils was assessed using 24 Jersey cows fed a control diet or the control diet supplemented at 35 g/kg dry matter (DM) with canola, soya bean, or a mixture of equal amounts of canola plus soya bean oil for 4-weeks. Total fatty acid content averaged 63 or 35 g/kg DM for oil-supplemented diets or control. Oleic acid accounted for 6, 29, 21 or 12 g/kg DM in the control, canola, mixture, or soya bean oil diet, respectively. Linoleic acid averaged 17, 19, 26, or 33 g/kg DM and linolenic acid 5, 5, 6 or 8 g/kg DM for control, canola, mixture, or soya bean oil. Concentrations of cis12-, trans11-, trans13+14, and trans15-18:1 were 0.81, 2.99, 2.24, and 0.73 mg/g rumen fluid, respectively, in response to soya bean oil and were 126, 90, 45, and 38% greater compared with other diets. Trans11cis15-, cis9trans11- and cis9 cis11-18:2 also were greater when soya bean oil (0.30, 0.34 and 0.01 mg/g, respectively) was fed compared with other treatments (0.12, 0.21 and 0.004 mg/g, respectively). Feeding canola oil resulted in greater concentrations of trans4-, trans5-, trans6+7+8-, trans9- and trans10-18:1 (0.20, 0.25, 0.87, 0.39 and 0.70 mg/g, respectively) compared with other diets (0.09, 0.15, 0.36, 0.20 and 0.46 mg/g, respectively). Trans10cis12-18:2 concentration did not differ as a result of diet and averaged 0.002 mg/g rumen contents. The pattern of 18:1 and 18:2 isomers formed during ruminal biohydrogenation depends greatly on dietary profile of unsaturated fatty acids.

<i>In vitro</i> ruminal fermentation and fatty acid production by various oil seeds

“…The vessel with FS contained a higher amount of linoleic acid (C 18:2, n-6 ) compared with the CD (P <0.01) and RS diets (P <0.05) and a higher amount of linolenic acid (C 18:3, n-3 ) compared with the CD (P <0.05) and SS diets (P <0.01). Loor et al (2002) have shown that C 18:1 , C 18:2, n-6 and C 18:3, n-3 from dietary rapeseed and soybean oils are converted primarily to C 18:0 and trans-C 18:1 isomers in ruminal fluid as a result of PUFA biohydrogenation by rumen microbes. The amounts of trans-vaccenic acid (C 18:1, n-11t ) and c-9, t-11 CLA were not influenced by the addition of oilseeds; only the amount of t-10, c-12 CLA was decreased by the addition of SS and FS (P  0.001) compared with the CD and RS diet.…”

Effect of oils rich in linoleic acid on <i>in vitro</i> rumen fermentation parameters of sheep, goats and dairy cows

“…The effect of fat on rumen fermentation depends on the type of fat, mostly on fatty acid saturation. The occurrence of C18:1 and C18:2 isomers depends on the dietary unsaturated fatty acid profile (Loor et al, 2002). In the case of the performed experiments, the origin of the rumen fluid rather than the type of fatty acids supplemented in the diet determined the concentration of long-chain fatty acids after fermentation.…”

Conjugated linolenic acid (CLnA), conjugated linoleic acid (CLA) and other biohydrogenation intermediates in plasma and milk fat of cows fed raw or extruded linseed

“…In our experiment, with diet C, the trans-13 1 14 18:1 proportion was 66% and 55% of that of trans-10 1 11 18:1 in plasma and milk, respectively, and proportions of trans-12 18:1, trans-15 18:1, and trans-16 18:1 were all around 10% of the total trans-18:1 in plasma and milk. Trans-12 18:1, trans-15 18:1, and trans-16 18:1 have already been suggested to be produced during cis-9, cis-12 18:2 BH (Loor et al, 2002), in addition to their production during cis-9 18:1 (Mosley et al, 2002) and cis-9, cis-12, cis-15 18:3 BH, and Piperova et al (2002) published a distribution of trans-18:1 isomers close to ours in the milk from cows fed a diet without added fat, and where cis-9, cis-12, cis-15 18:3 represented 10.8% of the total dietary FA. On the contrary, Loor et al (2005) found, with a diet without added fat but where cis-9, cis-12, cis-15 18:3 represented 25.8% of the total dietary FA, that trans-13 1 14 18:1 proportion was only 24% of that of trans-10 1 11 18:1 in milk, but 61% in plasma.…”

“…The samples were injected in 0.5 ml of hexane. Initial temperature of the oven was 708C, held for 1 min, increased by 58C/min to 1008C, held at 1008C for 2 min, increased by 108C/min to 1758C, held at 1758C for 40 min, increased by 58C/min to a final temperature of 2258C and maintained at 2258C for 15 min, as described by Loor et al (2002). Trans-10 18:1 and trans-11 18:1 were not completely separated with this method, and were considered together and designated as trans-10 1 11 18:1.…”