BackgroundThe filamentous fungus Talaromyces versatilis is known to improve the metabolizable energy of wheat-based poultry diets thanks to its ability to produce a pool of CAZymes and particularly endo-β(1,4)-xylanases. In order to appreciate their in vivo mode of action, the supplementation effect of two of its xylanases, XynD and XynB from families GH10 and GH11 respectively, have been evaluated on two different wheat cultivars Caphorn and Isengrain, which were chosen amongst 6 varieties for their difference in non starch polysaccharides content and arabinoxylan composition.ResultsPolysaccharides digestion was followed during 6 h along the digestive tract using the TNO gastrointestinal model-1, to mimic monogastric metabolism. Polysaccharide degradation appeared to occur mainly at the jejunal level and was higher with Isengrain than with Caphorn. For both cultivars, XynD and XynB supplementation increased notably the amount of reducing end sugars into the jejuno-ileal dialysates, which has been confirmed by a valuable increase of the soluble glucose into the jejunal dialysates.ConclusionsThe amounts of arabinose and xylose into the dialysates and ileal deliveries increased consequently mainly for Caphorn, suggesting that XynD and XynB supplementation in wheat-based diet could alleviate the anti-nutritional effects of arabinoxylans by limiting the physical entrapment of starch and could increase the available metabolizable energy.

The digestion of polysaccharides from the wheat cultivars Caphorn and Isengrain was investigated, and the efficiency of an enzyme preparation was tested using the TNO gastrointestinal model (TIM-1). The apparent digestibility (AD) of carbohydrates was determined based on the measurement of organic matter (OM), total monosaccharides, reducing ends (RE) and end products (EP: glucose, maltose and xylobiose). The AD of the OM from Caphorn and Isengrain measured using caecectomised cockerels did not differ from that measured using TIM-1: 72.0 (SD 2.6) v. 70.6 (SD 0.6) % for Caphorn (P = 0.580) and 73.0 (SD 2.3) v. 71.1 (SD 1.9) % for Isengrain (P = 0.252). After the 6 h TIM-1 digestion, 41.4-58.9 % of the OM, RE and EP were recovered from the jejunal compartment and 18.3-27.1 % from the ileal compartment, while ileal deliveries and digestive residues constituted the remainder. A commercial enzyme cocktail tested at 0.2 μl/g of wheat improved TIM-1 digestibility of Caphorn and Isengrain polysaccharides: 3.9 % (P = 0.0203) and 3.4 % (P = 0.0058) based on the OM; 9.7 % (P < 0.0001) and 3.1 % (P = 0.031) based on the total glucose; 47.2 % (P < 0.0001) and 14.2 % (P = 0.0004) based on the RE, respectively. The enzyme cocktail improved the release of the EP for Caphorn (3.8 %, P = 0.008) but not for Isengrain ( − 0.8 %, P = 0.561). The higher efficiency of the enzyme supplementation on the digestion of Caphorn polysaccharides compared with Isengrain seems to be linked to the higher soluble carbohydrate contents and/or less ramified arabinoxylan of Caphorn.

Edited by Laszlo Nagy Keywords:Bile salt dependent lipase activators Kinetic constants Taurocholate (Lyso)phosphatidic acid Platelet activating factor a b s t r a c tThe activity of breast milk BSDL was assayed with or without phospholipids as extra-intestinal effector candidates. Phosphatidic acid, lysophosphatidic acid and platelet activating factor but not phosphatidylcholine and lysophosphatidylcholine stimulated BSDL activity at least as efficiently as taurocholate. The apparent dissociation constants of PA and LPA at saturating concentrations of three different substrates were between 0.1 and 13.4 lM and that of PAF was below or equal to 200 pM. Kinetic data suggested the existence of at least one binding site for each of these effectors. PA, LPA and PAF are likely extra-intestinal modulators of BSDL activity.

Rumen protected forms of methionine have been developed to facilitate rationing of dairy cows in term of digestible methionine. It is essential for rumen protected products that the proportion of the amino acid that resists ruminal degradation as well as the proportion available in the intestine is known. Methods based on the concentration of amino acid in blood have been developed to provide fast and effective assessment of protection / release coefficients. The objective of this trial was to test the efficiency with which four different sources of methionine could deliver methionine to the blood of dairy cows.Two multiparous Friesian Holstein cows fitted with rumen and duodenal canulae and in their 10th week of lactation were used. They received a ration composed of corn silage ad libitum, soybean meal (2.5 kg/head/day) and concentrate (6.5 kg/head/day).

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