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Oat hulls, an agricultural byproduct, contain a relatively high amount of ferulic acid (FA; 4-hydroxy-3-methoxycinnamic acid), which is believed to be inhibitory to oat hull biodegradability by rumen microorganisms. In this paper, Aspergillus ferulic acid esterase (FAE) was investigated for its ability to release FA from oat hulls. The objectives were to determine the effects of particle size of oat hulls (ground to pass through 1 mm and 250 microm screens and a 100 microm sieve) on release of FA by FAE both in the presence and in the absence of Trichoderma xylanase. The results show that the release of FA by FAE was dependent upon the particle size of oat hulls (< or = 250 microm). In the absence of Trichoderma xylanase, little FA was released by FAE. In the presence of Trichoderma xylanase, there was a significant release of FA by FAE, indicating a synergistic interaction between FAE and Trichoderma xylanase on release of FA from oat hulls. These results indicate that FAE is able to break the ester linkage between FA and the attached sugar, releasing FA from oat hulls. This may leave the remainder of the polysaccharides open for further hydrolytic attack by rumen microorganisms. It is likely that removing FA from oat hulls could improve rumen biodegradability, thus improving the nutritional value of oat hulls.

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Hydroxycinnamic acids, mainly ferulic and p-coumaric acids, are believed to be inhibitory to ruminal biodegradability of complex cell wall materials such as oat hulls. Previous studies have shown that a novel enzyme, Aspergillus ferulic acid esterase, and Trichoderma xylanase act synergistically to break the ester linkage between ferulic acid and the attached sugar of feruloyl polysaccharides, releasing ferulic acid from oat hulls. In this paper, we examined the enzymic release of reducing sugars from oat hulls by the actions of individual enzymes (Aspergillus ferulic acid esterase at 13 mU, 6.4 U, and 4678.4 U/assay; cellulase at 20 levels, ranging from 7.8 mU to 2772.7 U/assay; Trichoderma xylanase at 20 levels, ranging from 7.8 mU to 4096 U/assay) and by the combined action of cellulase at six levels (62.5 mU, 2 U, 16 U, 128 U, 1024 U, and 2772.7 U/assay), Aspergillus ferulic acid esterase at 13 mU/assay, and Trichoderma xylanase at two levels (1 U and 256 U/assay). The amount of total acid-extractable reducing sugars in the oat hulls used in this study was 793.8 +/- 8.0 microg/mg. The results show that after a 24-h incubation with Aspergillus ferulic acid esterase alone, no reducing sugars were observed to be released from oat hulls. With cellulase as the sole enzyme, as the concentration increased from 7.8 mU to 2772.7 U/assay, the release of reducing sugars increased (P < 0.01) from 0 to 39% of the total present, with the highest release at 512 U/assay. With Trichoderma xylanase alone, as the concentration increased from 7.8 mU to 4096 U/assay, the release of reducing sugars increased (P < 0.01) from 4.9 to 33%, with the highest release at 2048 U/assay. When incubated together with Trichoderma xylanase (1 U or 256 U/assay) and Aspergillus ferulic acid esterase (13 mU/assay), cellulase at all six levels (62.5 mU, 2 U, 16 U, 128 U, 1024 U and 2772.7 U/assay) significantly increased the release of reducing sugars (P < 0.01) from 8 to 69%. These results indicate that the synergistic interaction between Aspergillus ferulic acid esterase and Trichoderma xylanase on the release of ferulic acid from feruloyl polysaccharides of oat hulls makes the remainder of the polysaccharides open for further hydrolytic attack and facilitates the accessibility of the main chain of polysaccharides to cellulase. This action extends the cell wall hydrolysis, thus releasing a higher yield of reducing sugars. Such enzymic pretreatment of oat hulls may provide a unique advantage to rumen microorganisms for the biodegradation of the complex cell walls of byproduct feeds such as oat hulls.

p-Coumaric acid (4-hydroxycinnamic) and ferulic acid (4-hydroxy-3-methoxycinnamic), two major hydroxycinnamic acids found in the complex cell walls of oat hulls, act as cross-linking agents between lignin and polysaccharides or between polysaccharides. As such, they are inhibitory to the biodegradation of cell walls by microorganisms. A previous study showed that Aspergillus feruloyl esterase with Trichoderma xylanase was able to break the ester linkage between ferulic acid and the attached sugar, releasing ferulic acid from the cell wall. The objective of this study was to investigate the specificity and the ability of Aspergillus feruloyl esterase to release p-coumaric acid from oat hulls. The results show there was no extensive release of p-coumaric acid in both the absence and presence of Trichoderma xylanase by Aspergillus feruloyl esterase. This indicates a specificity of Aspergillus feruloyl esterase, which is more active only on esters of certain hydroxycinnamic acids; in this case, Aspergillus feruloyl esterase will only sufficiently break the ester-linked feruloyl group but not the p-coumaroyl group in the complex cell walls of oat hulls.

. 2000. The feeding value of grain screenings for ruminants: Chemical composition and nutrient utilization. Can. J. Anim. Sci. 80: 673-680. The objectives of this study were to determine the chemical and nutrient utilization characteristics of grain screening pellets (GSP) for ruminants. One ruminally fistulated cow was used to determine ruminal nutrient degradability characteristics of GSP relative to barley grain. Twentyone growing lambs were used to determine voluntary intake and total tract nutrient digestibility coefficients for GSP relative to regular and thin barley. Seven diets were formulated with different levels of GSP, and thin or regular barley at ratios of 100:0; 75:25; 50:50; 25:75. On a dry matter (DM) basis, GSP contained 337 ± 17.4 g kg -1 neutral detergent fiber (NDF), 209 ± 21.1 g kg -1 acid detergent fiber (ADF), 151 ± 11.1 g kg -1 crude protein (CP), and 262 ± 61.5 g kg -1 starch. Ruminal degradability of DM and NDF of GSP was lower (P < 0.05) while that for CP was higher (P < 0.05) than barley grain. Effective ruminal degradability of starch for GSP and barley exceeded 900 g kg -1 . Results of the sheep trial showed that as the level of GSP increased, voluntary intake increased (P < 0.05) and total tract digestibility coefficients of DM, NDF, and gross energy (GE) decreased (P < 0.05). The digestibility coefficients of DM, NDF, and GE for GSP were 666 g kg -1 , 294 g kg -1 , and 698 J kJ -1 , respectively. The digestible energy (DE) content of GSP (13.8 MJ kg -1 ) was similar to that of thin barley and 11% lower (P < 0.5) than that of regular barley. It was concluded that while GSP exhibited reduced ruminal and total tract nutrient utilization relative to regular barley, this feed product is a good source of energy and protein for growing ruminants. La dégradabilité ruminale réelle de l'amidon des deux ingrédients dépassait 900 g kg -1 . Les essais conduits sur les moutons révèlent qu'à mesure qu'on augmente la proportion d'a.c.c., la prise alimentaire libre s'accroît (P < 0,05), tandis que les coefficients de digestibilité globale de m.s., FDN et EB (énergie brute) diminuent (P < 0,05). Les coefficients de digestibilité de m.s., FDN et EB étaient, dans l'ordre, de 666 g kg -1 , 294 g kg -1 et 698 J kJ -1 . Le contenu en ED des a.c.c. (13,8 MJ kg -1 ) était du même ordre que celui de l'orge maigre et 11 % plus bas (P < 0,05) que celui de l'orge du commerce. Il découle de ces observations que, malgré une digestibilité ruminale globale moindre que celle de l'orge standard, les a.c.c constituent une bonne source d'énergie et de protéine pour les ruminants en croissance.

. 2002. The interactive effects of enriched sources of Aspergillus ferulic acid esterase and Trichoderma xylanase on the quantitative release of hydroxycinnamic acids from oat hulls. Can. J. Anim. Sci. 82: 251-257. Oat hulls contain relatively high amounts of hydroxycinnamic acids, mainly ferulic (4-hydroxy-3-methoxycinnamic) and p-coumaric acids (4-hydroxy-cinnamic), which are inhibitory to cell wall biodegradability by rumen microorganisms. In this paper, a study of the interactive effects of enriched sources of Aspergillus ferulic acid esterase (A-FAE) and Trichoderma xylanase (T-XYL) at different levels on the quantitative release of ferulic acid and p-coumaric acid from oat hulls was carried out. The results show that relative to A-FAE alone, the combined action of A-FAE and T-XYL was superior in causing the release of ferulic acid [up to 41.0% (± 2.1%)], indicating that T-XYL is important in acting with A-FAE in the degradation of feruloyl-polysaccharides of oat hulls. There was no effect of A-FAE alone, but a significant effect of A-FAE in combination with T-XYL on the release of p-coumaric acid from oat hulls. However, there was no extensive release of p-coumaric acid [(maximum release of 9.0% (± 0.7%)] by A-FAE in the presence of T-XYL, indicating a specificity of A-FAE for feruloyl groups, which only efficiently releases ferulic acid and not p-coumaric acid from oat hulls. This study suggests that A-FAE with T-XYL has an interactive effect to be able to break the ester linkage between ferulic acid and the attached sugar, releasing a significant proportion of the ferulic acid from oat hulls. This action, which causes disruption of crosslinks, has the potential to improve hydrolysis of the remaining polysaccharides by rumen microorganisms, which, in turn, would improve rumen degradability of oat hulls. ] que l'A-FAE seule, signe que le T-XYL joue un rôle important en intervenant avec l'A-FAE dans la dégradation des féruloyl-polysaccharides présents dans la bale d'avoine. Si l'A-FAE seule n'agit pas sur la libéra-tion de l'acide p-coumarique par la bale d'avoine, son action est importante une fois combinée au T-XYL. En présence de T-XYL, l'A-FAE n'entraîne toutefois pas la libération d'une grande quantité d'acide p-coumarique (maximum de 9,0 (± 0,7) %). On en déduit que l'A-FAE agit spécifiquement sur les groupes féruloyle, qui permettent la libération d'acide férulique mais pas d'acide p-coumarique dans la bale. Les résultats donnent à penser qu'en interagissant avec le T-XYL, l'A-FAE réussit à briser le pont ester qui fixe l'acide férulique à son sucre, libérant ainsi une quantité importante de cet acide dans la bale d'avoine. Cette action perturbe les ponts intercaténaires, ce qui pourrait améliorer l'hydrolyse des autres polysaccharides par les microorganismes du rumen, donc aboutir à une meilleure dégradation de la bale d'avoine.Mots clés: Estérase de l'acide férulique, bale d'avoine, acides hydroxycinnamiques, biodégradation 251Oat hulls comprise 26 to 31% of the weight of the oat seed, and are an a...

Thacker, P. A., Racz, V. J. and Soita, H. W. 2004. Performance and carcass characteristics of growing-finishing pigs fed barley-based diets supplemented with Linpro (extruded whole flaxseed and peas) or soybean meal Can. J. Anim. Sci. 84: 681-688. The objective of this experiment was to determine the effects of feeding graded levels of Linpro (a 50:50 combination of extruded full-fat flax seed and peas) on pig performance and carcass traits, particularly the fatty acid composition of backfat. Eighty crossbred pigs (Camborough 15 Line female × Canabred sire, Pig Improvement Canada Ltd., Airdrie, AB) weighing an average of 22.7 ± 2.2 kg were assigned on the basis of sex, weight and litter to one of five dietary treatments in a 5 × 2 factorial arrangement (treatment × sex). The experimental diets were based on barley and soybean meal and contained 0, 7.5, 15, 22.5 or 30% Linpro during the growing period (22.7-69.7 kg) and 0, 6, 12, 18 or 24% Linpro during the finishing period (69.7-111.1 kg). Digestibility coefficients for dry matter were not significantly affected by incorporation of Linpro in the diet. Digestibility coefficients for crude protein (P = 0.01) and gross energy (P = 0.04) exhibited a cubic effect due to Linpro incorporation with the highest digestibility coefficients observed for pigs fed 7.5% Linpro. Over the entire experimental period (22.7-111.1 kg), daily gain was affected both linearly (P = 0.02) and quadratically (P = 0.04) by Linpro inclusion. The most rapid gains were obtained by pigs fed 7.5% Linpro (6% in finisher), while pigs fed 30% Linpro (24% in finisher) gained weight the slowest. Feed intake was not significantly affected by Linpro inclusion, while feed conversion exhibited a quadratic effect (P = 0.02) with pigs fed the highest and lowest levels of Linpro showing the poorest feed conversion. Linpro inclusion, had no significant effects on carcass traits including slaughter weight, carcass weight, dressing percent, carcass value index, lean yield, loin fat or loin lean. Inclusion of 30% Linpro (24% in finisher) significantly (P < 0.05) increased the levels of linolenic acid in backfat and this increase could provide significant health benefits for consumers of pork. Linpro would appear to be an acceptable alternative to soybean meal as a protein supplement for use in growing-finishing swine diets and can be incorporated at levels as high as 22.5% in the grower period and 18% in the finisher period without detrimental affects on pig performance. Sci. 84: 681-688. L'expérience devait établir les conséquences de l'ingestion d'une quantité établie de Linpro (mélange à parts égales de graines de lin entières extrudées et de pois) sur le rendement des porcs et sur les paramètres de la carcasse, en particulier la teneur du gras dorsal en acides gras. Quatre-vingts sujets hybrides (femelles Camborough de lignée 15 × mâles Canabred, Pig Improvement Canada Ltd, Airdrie, Alberta) pesant en moyenne 22,7 ± 2,2 kg ont été répartis en fonction du sexe, du poids et de la portée entre cinq régimes dan...