| The study was conducted to determine optimum ratio activity of the xylanase which hydrolyzed the wheat-based diet instead of corn-based diet in varying levels using digestion device in vitro to imitate nutrients digestion in broiler. Under the condition of wheat-based diet instead of corn-based diet in different degrees in the broiler diet, research the effect of xylanase which are the best level provided by in vitro addition in wheat-based diet on production performance, nutrient metabolic rate, digestion enzyme activity, serum biochemical parameters immune function, intestinal microflora digestive tract weight and structure in broilers.Experiment.1 Study on Screening of Xylanase Hydrolyzed Wheat-based Diet in Vitro in broilersThis study was conducted to test the effects of xylanase through measuring the levels of the net reducing sugar production quantity in five levels of the xylanase which hydrolyzed the wheat-based diet instead of corn-based diet in varying levels applying digestion device in vitro to imitate nutrients digestion in broiler, in order to establish the quantitive relationship between xylanase level and wheat-based diet. The results showed that : the appropriate dietary xylanase levels for wheat-level one (the wheat content is 18.6% in the dietary),wheat-level two (the wheat content is 37.2% in the dietary) and wheat-level three (the wheat content is 55.8% in the dietary)were27.08247U/g,40.69318U/g和48.61111U/g based on the net reducing sugar production quantity. Because of the enzyme activities of the xylanase provided by the green Kang Mu company is 25,000U/g, obtained the optimal adding percentage of xylanase offered by green KangMu company under different wheat replacement level, wheat-level one is: 0.1%, the wheat-level two is: 0.16% and the wheat-level three is: 0.20%, the animal experiments followed this scheme.Experiment.2 Effects of Xylanase Supplementation on Performance, Blood Parameters and Immune FunctionA total of 288, 1 day-old straight-run broiler chickens (Arbor Acres, AA) were purchased from a commercial hatchery, then randomly divided into four treatments, each treatment has six replicates and twelve chicks in each replicate. A corn-soybean meal diet was formulated as control, 33.33%, 66.67% and 100% wheat instead of corn with optimal levels of xylanases in three groups as experimental ones. The results were as follows: 1) during 1 to 6 week, the broilers'ADG were raised in all experimental groups, and feed transformation efficiency was not remarkable (P>0.05),achieved and even more than the conventional corn-soybean's effect; 2) Nutritional factors (diet quantity and composition) also affect intermediary metabolism, resulting in the changes of plasma metabolite levels in broiler, this in turn was responsible for an enhanced rate of metabolism and accelerated growth in certain extent after the xylanase was added in broilers'wheat diet.Experiment.3 Effect of Xylanase Addition in Wheat-based Diet on Feed Apparent Utilization and Digestion Enzyme ActivityTwenty 6-week-old Avain roosters(average weight is 2.00±0.20 kg) were randomly divided into four groups, each group of five chickens, A corn-soybean meal diet was formulated as control, 33.33%, 66.67% and 100% wheat instead of corn with optimal levels of xylanases in three groups as experimental ones.In order to study the effect of xylanase addition in wheat-based diet on feed apparent utilization and digestion enzyme activity. The results were as follows: The effects of exogenous enzyme in the wheat-based diets on broiler was the digestibility of CP was tended to be lower (P>0.05) and apparent energy digestibility improved over the unsupplemented control, there was significant difference between the treament two and the control group (P>0.05); in treament 1 and treament 2, apparent calcium digestibility is better than the control; treament 2 is higher than the control with apparent Phosphorus digestibility (P>0.05); enzyme supplementation to wheat-based diets apparent fat digestibility was tended to be lower fed with enzyme supplement than that of the control, there was no significant difference between them(P>0.05).In all, NSP-hydrolyzing enzyme preparations (xylanase) when added to wheatbased diets can improve nutrient metabolic rate such as apparent energy digestibility and so on in broiler chickens,and increased the activity of amylase and trypsin in a certain extent.Experiment.4 The effects of xylanase supplementation on gut microflora and digestive organs in broilers fed on wheat-based dietsThe aim of this study was to investigate the effects of xylanase suppleentation on gut microflora, relative weight of digestive organs, pH of gastrointestinal tract digesta and characteristics of the gastrointestinal tract in broilers fed on different nutrition level of wheat-based diets. Two hundred and eighty-eight one-day-old Arbor Acre broilers were randomly divided into four treatments, each treatment has six replicates and twelve chicks in each replicate. A corn-soybean meal diet was formulated as control, 33.33%, 66.67% and 100% wheat instead of corn with 0.1%,0.16% and 0.2% levels of xylanases in three groups as experimental ones. The results were as follows:1) The counts of lactobacillus and anaerobic tended to be higher and the counts of aerobic coliform bacteria tended to be lower (P>0.05) in caecum contents of birds fed with enzyme supplement than that of the control.2) The results showed that the addition of enzyme to a wheat-based diet reduced the relative weights of the proventriculus, gizzard and ileum, the relative weights of jejunum, ileum, caecum and pancreas were no significant difference between the experimental groups and the control group (P>0.05).3) The digesta pH and the gastrointestinal tissue morphology was altered in certain extent after the xylanase was added in broilers'wheat diet. |
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