Effects of preconditioning and extrusion of linseed on the ruminal biohydrogenation of fatty acids. 1. In vivo studies

Abstract

-The extent and intermediates of ruminal biohydrogenation (BH) of fatty acids (FA) from a blend of linseed and wheat bran (70:30) were investigated in the rumen fluid, rumen particle phase and duodenal flow. The blend was ground through a 3 mm screen and used raw or extruded, or was ground through a 6 mm screen and preconditioned. Three dry Holstein cows fitted with ruminal and duodenal cannulas were used in a 3 × 3 Latin square design, with 18 days adaptation. The diet contained 20% (DM basis) of the linseed based blend. Twelve samples taken over 3 days were composited for analysis of rumen fluid, rumen particle phase and duodenal flow. The BH of FA from linseed resulted in the appearance of a great number of C18:1 intermediates, among which trans-10+11 to trans-16C18:1 were the most abundant. The proportion of cis-9,trans-11C18:2 was low. Preconditioning coarsely ground linseed resulted in a lower extent of C18:2 and C18:3 BH, and lower proportions of trans-12 to trans-16C18:1 intermediates than extrusion or a lack of processing of finely ground linseed. On the contrary, extrusion did not affect the extent of BH and had no significant effect on the proportions of trans-C18:1 intermediates, but increased the proportion of cis-9,trans-11C18:2 in both rumen phases. Different digesta types resulted in different estimates of BH. The extent of BH and the proportions of trans-C18:1 intermediates were lower in the rumen particle phase and higher in the rumen fluid than in the duodenum. Moreover, interactions between digesta type and treatment of linseed were observed. était broyé à la grille de 3 mm et utilisé cru ou extrudé, ou broyé à la grille de 6 mm et précon-ditionné. Trois vaches Holstein taries, équipées de canules ruminale et duodénale, ont été utilisées dans un protocole en carré latin 3 × 3, avec 18 jours d'adaptation par période. La ration contenait 20 % (par rapport à la matière sèche) de mélange à base de lin. Douze échantillons de phases solide et liquide du rumen et de contenu duodénal, ont été prélevés sur 3 jours et mélangés avant analyse. La BH des acides gras du lin a conduit à l'apparition d'un grand nombre d'intermédiaires C18:1trans, parmi lesquels les trans-10+11 à trans-16 étaient les plus abondants. La proportion de C18:2cis-9,trans-11 était faible. Le préconditionnement du mélange grossièrement broyé a conduit à une BH de C18:2 et C18:3 et des proportions de C18:1trans-12 à trans-16 plus faibles que l'extrusion ou l'absence de traitement de mélange finement broyé. Au contraire, l'extrusion n'a pas modifié l'importance de la BH ou les proportions de C18:1trans, mais a augmenté la proportion de C18:2cis-9,trans-11 dans le rumen. Les différents types de prélèvement ont conduit à différentes estimations de la BH. L'importance de la BH et les proportions d'intermédiaires trans-C18:1 étaient plus faibles dans la phase solide et plus élevées dans la phase liquide du rumen que dans le contenu duodénal. En outre, des interactions entre type de digesta et traitement du lin ont été observées.b...

Effects of the heating process of soybean oil and seeds on fatty acid biohydrogenation in vitro

“…Nevertheless, in the study of Privé et al (2010), increasing duration and temperature of oil heating increased trans-10 isomers and decreased trans-11 isomers, contrary to in vivo or in situ observations with roasted or extruded oilseeds (Gonthier et al, 2005;Akraim et al, 2006;TroegelerMeynadier et al, 2006b).…”

“…In the dairy cow diet, fat is usually carried out by oilseeds, which are often heated; for example, by roasting or extrusion. These processes have been shown to have variable effects on BH among studies, which need to be specified and Effects of the heating process of soybean oil and seeds on fatty acid biohydrogenation in vitro explained: heated oilseeds often induced a decrease in cis-9,cis-12 C18:2 and cis-9,cis-12,cis-15 C18:3 BH in vivo (Gonthier et al, 2005), in situ (Chouinard et al, 1997b;Troegeler-Meynadier et al, 2006b), and in vitro (Reddy et al, 1994); however, this partial protection of PUFA against BH was not always noticed (Akraim et al, 2006;Neves et al, 2007;Abdi et al, 2013). Moreover, in most of these studies, heat treatments resulted in an accumulation of BH intermediates, particularly cis-9,trans-11 CLA or trans-11 C18:1, or both.…”

Feeding Extruded Linseed to Dairy Ewes Under Extensive Grazing Conditions

“…In addition, no differences in milk fat content were reported by Gomez-Cortés et al (2009) when ewes were fed extruded linseed (12% DM). Usually, the dietary lipids in ruminant rations contributed significantly to the energy density of the diet, which is reflected in an increased milk yield (Akraim et al, 2006). The supplementation of TEL affected some of the physical characteristics of milk, and despite the increase in milk pH, this value is within the physiological range reported for sheep milk (Park et al, 2007).…”

Effects of preconditioning and extrusion of linseed on the ruminal biohydrogenation of fatty acids. 2. In vitro and in situ studies

“…In vivo studies have shown BH extents over 80% for both PUFA [3,10,19], which suggests an underestimation of BH extent with the former investigation methods. The slow in vitro FA disappearance could be due to the accumulation of intermediates and end-products of fermentation or BH in the flasks during incubation.…”

“…One part of FA methyl esters of each sample was fractionated by argentation TLC (plates 20 × 20 cm, Silica gel 60, Merk KGaA, Germany) as described by Le Doux et al [17], Total and trans-C18:1 FA were analysed by GLC (Agilent 6890N, equipped with a model 7683 auto injector, Network GC System, Palo alto, California, USA) as previously described [3].…”