| 1 | Development of an in vitro protein digestibility assay mimicking the chicken digestive tract显示文摘It is difficult to obtain in vivo digestion kinetics data of high protein ingredients using chickens. Collecting kinetics data requires repeated sampling of digesta from the small intestine during the digestion process,which is not easily accomplished due to the anatomical structure of chicken digestive tract. An in vitro technique is proposed for measuring the digestion kinetics of protein sources fed to chickens. The method has a 30 min gastric and 3 h intestinal phase. Five hundred milligram crude protein(CP)equivalent of each meal sample(CP = % N × 6.25) was digested with pepsin(28,260 units) in 50 m L polyethylene centrifuge tubes for 30 min in a shaking water bath(150 strokes/min; 30 mm stroke length)at 41C. The 6.5 mL pancreatin was selected as the enzyme concentration for the intestinal phase, during which time 500 m L aliquots were collected at 0, 15, 30, 45, 60, 90, 120, 150, 180 and 240 min. Samples were diluted 1:820 with HCl and sodium acetate buffer, and then mixed with ninhydrin reagent(2:1) at100 ± 2C for 15 min and spectrometric readings taken at 568 nm. To validate the assay, 5 replications of soybean meal(SBM), corn gluten meal(CGM), corn distillers dried grains with solubles(CDDGS), porcine meal(PCM), fish meal(FM) and casein(CA) were digested. The digestion data were modeled with PROC NLIN procedure, and the intra coefficient of variation(CV) assessed using PROC MEANS of SAS 9.4. The digestion values at 180 min were SBM 95 ± 4, FM 93 ± 3, PCM 68 ± 4, CGM 82 ± 3 and CDDGS 70 ± 2.Intra CV for SBM, CGM, CDDGS, PCM and FM were 5%, 5%, 12%, 10% and 2%, respectively. The estimated fractional digestion rates for SBM, CGM, CDDGS, FM and PCM were 0.023, 0.013, 0.009, 0.024 and 0.013,respectively. In conclusion, the proposed in vitro technique estimated the rate and extent of the digestion of CP for the meals with low intra CV. | Dervan D.S.L.Bryan Dawn A.Abbott Henry L.Classen | 2018 | Animal Nutrition2018，，4： | 6 |
| 2 | Diet medication and beta-glucanase affect ileal digesta soluble betaglucan molecular weight,carbohydrate fermentation,and performance of coccidiosis vaccinated broiler chickens given wheatbased diets显示文摘Exogenous enzymes as alternatives to feed antibiotics in poultry has become an emerging research area with the emergence of antibiotic resistance.The objective was to evaluate the effects of diet medication(antibiotics)andβ-glucanase(BGase)on digesta solubleβ-glucan depolymerization,carbohydrate fermentation,and performance of coccidiosis-vaccinated broiler chickens fed wheat-based diets.A total of 1,782 broilers were raised on litter floor pens,and each treatment was assigned to 1 pen in each of the9 rooms.The 3 dietary treatments were based on wheat as the sole grain(control,control+medication and control+0.1%BGase),and the birds were fed the respective treatments ad libitum from 0 to 33 d.Treatments were arranged in a randomized complete block design and analyzed as a one-way ANOVA.Beta-glucanase reduced the peak molecular weight,weight average molecular weight(Mw)and maximum molecular weight for the smallest 10%β-glucan molecules(MW-10%)in ileal digesta at d 11and 33,whereas diet medication reduced Mw and MW-10%at d 33 compared to the control(P<0.01).Beta-glucanase and medication reduced the ileal viscosity at d 11 compared to the control(P=0.010).Ileal propionic acid concentration at d 11 and caecal total SCFA,acetic,and butyric acid concentrations at d 33 were lower in the BGase-supplemented diet than in the control(P<0.05).The BGase-added diet had higher duodenal p H compared to the control at d 33(P=0.026).The effect of medication on carbohydrate fermentation was minimal.Diet medication increased weight gain after d 11,whereas BGase increased the gain for the total trial period compared to the control(P<0.001).Feed intake was not affected by the dietary treatment.Medication and BGase improved feed efficiency after d 11 compared to the control(P<0.001).The response to diet medication was larger than BGase,considering weight gain and feed efficiency after d 11(P<0.001).In conclusion,diet medication and BGase depolymerized high molecular weight ileal solubleβ-glucan and increased overall bird performance.Dietary BGase may benefit bird health in broilers fed wheat-based diets without medication. | Namalika D.Karunaratne Henry L.Classen Andrew Gvan Kessel Michael R.Bedford Nancy P.Ames Rex W.Newkirk | 2023 | Animal Nutrition2023，，4： | 0 |
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