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1. The effects of 3 commercial enzyme products on the nutritive value of 2 lupin species were investigated with the emphasis on changes in composition of non-starch polysaccharides (NSPs) along the digestive tract. Enzyme A contained primarily cellulase, beta-glucanase and xylanase activities, enzyme B primarily hemicellulase, pentosanase and xylanase activities, and enzyme C primarily hemicellulase, pectinase and beta-glucanase activities. 2. The enzymes were added to semi-purified diets based on sorghum and casein containing 35% whole seed lupins (Lupinus angustifolius cv Gungurru or Lupinus albus cv Kiev mutant). Control diets contained no lupins. 3. Food conversion ratio (FCR), excreta moisture content and apparent metabolisable energy (AME) were affected by lupin species but not by enzyme supplementation. 4. In diets with L. angustifolius, enzyme C significantly increased digesta viscosity and increased the concentration of soluble NSPs in all sections of the intestine. 5. Digestibility of protein and NSPs in the ileum and microbial fermentation in the ileum and caeca were not affected by adding enzymes to diets containing L. angustifolius. 6. Enzyme addition to diets with L. albus did not affect digesta viscosity nor concentration of soluble NSPs but caused a significantly (P<0.05) reduced concentration of insoluble NSP in the ileum. 7. Enzyme addition to L. albus significantly (P<0.05) increased NSP digestibility in the ileum but had no effects on protein digestibility and fermentation in the ileum and caeca. 相似文献
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Mueller CA Broz P Müller SA Ringler P Erne-Brand F Sorg I Kuhn M Engel A Cornelis GR 《Science (New York, N.Y.)》2005,310(5748):674-676
Many pathogenic bacteria use injectisomes to deliver effector proteins into host cells through type III secretion. Injectisomes consist of a basal body embedded in the bacterial membranes and a needle. In Yersinia, translocation of effectors requires the YopB and YopD proteins, which form a pore in the target cell membrane, and the LcrV protein, which assists the assembly of the pore. Here we report that LcrV forms a distinct structure at the tip of the needle, the tip complex. This unique localization of LcrV may explain its crucial role in the translocation process and its efficacy as the main protective antigen against plague. 相似文献
3.
Size determination represents a fundamental requirement for multicomponent biological structures. Some pathogenic bacteria possess a weapon derived from the flagellum. Like the flagellum, this type-III secretion apparatus, called the injectisome, has a transmembrane basal body, but the external component is a needle-like structure instead of a hook and a filament. Here, we provide evidence that the length of this needle is determined by the size of a protein, YscP, acting as a molecular ruler. 相似文献
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Generalized subcutaneous emphysema in a dog 总被引：2，自引：0，他引：2
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J. Broz P. Oldale A.‐H. Perrin‐Voltz G. Rychen J. Schulze C. Simoes Nunes 《British poultry science》1994,35(2):273-280
1. Three experiments were conducted to evaluate the effects of the dietary addition of fungal phytase (derived from Aspergillus niger) on the performance and phosphorus utilisation in broiler chickens receiving low phosphorus diets without additional inorganic phosphates.
2. Graded amounts of supplemental phytase (125, 250, or 500 PU/kg diet) resulted in significant increases in both growth rate and food intake. However, only moderate improvements in food conversion were noted.
3. The enhancement of chick performance was related to an improved utilisation of dietary phosphorus, as confirmed by significantly elevated plasma concentrations of inorganic phosphorus and increased tibia ash percentages in birds receiving phytase‐treated diets. The apparent availability of phosphorus was markedly improved and its concentration in excreta was reduced (experiment 1, P<0.05).
4. It was concluded that an inclusion of phytase into practical broiler diet will allow the reduction or omission of additional dietary inorganic phosphorus. 相似文献
6.
The effects of feeding benzoic acid on weanling pig performance and on the ecology of their gastrointestinal microbiota were evaluated. One hundred and forty-four piglets (4 weeks of age) were used. Half of the piglets were fed a control diet and half were fed the same diet with 0.5% benzoic acid, and their performance was measured for 28 days. At the end of the trial, twelve piglets from each treatment were euthanised and samples of ileal and caecal digesta were collected. The digesta samples were cultured to quantify Lactobacillus spp., Escherichia coli,Enterococcus spp. and Clostridium perfringens and they were also studied by restriction fragment length polymorphism to evaluate the biodiversity degree and the similarity between the profiles of the microbiota. Benzoic acid improved piglets’ performance, and this was associated with a greater ileal microbiota biodiversity. 相似文献
7.
1. Two trials were conducted to evaluate the effects of a mono-component thermostable endo-1,4-β-xylanase derived from Thermomyces lanuginosus on the nutritive value of wheat-based broiler diets. In a 5-week growth trial, the efficacy of xylanase supplementation at 0, 100, 150, 200, 400 and 4000 FXU/kg diet was evaluated. A short-term balance trial was carried out according to a 4?×?2 factorial arrangement of treatments, involving 4 wheat cultivars and endo-xylanase at 0 or 200 FXU/kg. 2. In the growth trial, enzyme supplementation from 0 to 400 FXU/kg reduced feed intake and improved feed conversion linearly. Digesta viscosity was significantly reduced by all enzyme inclusion levels by 49·6–56·9%, in a quadratic manner. 3. In the balance trial, xylanase supplementation resulted in a significant improvement of protein, lipid and dry matter apparent digestibility coefficients of diets, accompanied by improved dietary AME N values. There was a significant wheat?×?enzyme interaction on AME N and lipid digestibility. There was a significant effect of wheat cultivar on dry matter digestibility. 相似文献
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1. The effects of two enzyme products on the nutritive value of soyabean meal (SBM) were investigated with the emphasis on changes in composition of non-starch polysaccharides (NSP) along the digestive tract. Enzyme A was a commercially available product containing mainly hemicellulase, pectinase, beta-glucanase and some protease activities and Enzyme B was an experimental product with mainly beta-galactanase activity. 2. Enzymes were added at the recommended dosage (normal) and at 5 times the recommended dosage (high) to a semi-purified diet based on maize with SBM as the sole protein source. 3. The enzymes had no effect on digesta viscosity in the jejunum or ileum. 4. Enzyme A at the high dosage significantly (P<0.05) improved AMEN, reduced excreta moisture content and improved ileal protein digestibility. The addition of the same enzyme at the recommended dosage had no effect on any of the above parameters. 5. Analysis of the monosaccharide composition revealed that Enzyme A tended to reduce the amounts of rhamnose and galactose in the soluble and insoluble NSP fractions in thejejunal and ileal digesta. The reduction was significant (P<0.05) when the same enzyme was added at the high dosage. 6. Enzyme B significantly (P<0.05) improved AMEN of the diet but not the growth or the feed conversion ratio (FCR) of the birds. Enzyme B at the high dosage significantly reduced (P<0.05) ileal protein digestibility. 7. Enzyme B significantly (P<0.05) increased the amount of free sugars in thejejunum and reduced (P<0.05) the concentration of soluble NSP in the ileum. 8. Analysis of the monosaccharide composition in the jejunal and ileal digesta showed that this enzyme was highly effective in releasing galactose from both the soluble and insoluble NSP fractions. 9. It is concluded that glycanases with galactanase and pectinase activities supplemented at appropriate dosages can improve the digestibility of the NSP in SBM and increase the metabolisable energy content of the diet containing high levels of SBM. 10. Furthermore, the addition of Enzyme B at the high dosage significantly (P<0.05) reduced protein digestibility without any measurable reduction in growth performance. 相似文献
10.
In order to investigate the effects of benzoic acid on growth performance, nutrient digestibility, nitrogen balance and gastrointestinal microflora of piglets, we conducted a performance experiment and a separate balance study. The performance experiment involved four different dietary treatments: (1) basal diet (negative control); (2) basal diet supplemented with benzoic acid at 5 g/kg; (3) basal diet supplemented with benzoic acid at 10 g/kg; (4) basal diet supplemented with potassium diformate at 12 g/kg. Each dietary treatment was assigned to nine replicate groups, each consisting of two piglets. Live weight, daily weight gain, feed intake and feed conversion ratio were monitored as performance parameters over a 35-day period. Supplementation of the diet with benzoic acid resulted in a dose-dependent increase in feed intake and body weight gain and an improved feed conversion ratio. Piglets fed the diet supplemented with benzoic acid at 10 g/kg outperformed the control piglets in mean feed intake, body weight gain and feed conversion ratio by 9%, 15% and 6% respectively. Growth performance of the piglets fed the diet with benzoic acid at 10 g/kg was similar to that of piglets fed the diet supplemented with potassium diformate. In the balance experiment three groups of six piglets each were fed either a control diet or diets supplemented with benzoic acid at 5 or 10 g/kg respectively. Benzoic acid did not significantly affect nutrient digestibility but increased nitrogen retention. Piglets fed the diets supplemented with benzoic acid at 5 or 10 g/kg retained 5% and 6% more nitrogen, respectively, than control piglets. Supplementation of benzoic acid did not influence the pH value or the concentration of ammonia in the gastrointestinal tract but reduced the number of bacteria in the digesta. In the stomach the number of total aerobic, total anaerobic, lactic acid forming and gram-negative bacteria was reduced; in the duodenum the presence of benzoic acid reduced the number of gram-negative bacteria and in the ileum the number of total aerobic bacteria in a dose-dependent manner. Benzoic acid also considerably reduced the concentration of acetic acid in the duodenum. In conclusion, the data of this study suggest that benzoic acid exerts strong antimicrobial effects in the gastrointestinal tract of piglets and therefore enhances growth performance and nitrogen retention. 相似文献