柠檬酸对肉鸡肠道pH值与微生物数量的影响

通过饲喂添加0．1％、0．2％、0．3％柠檬酸的日粮,研究其对肉鸡肠道pH值及肠道微生物的影响。试验结果发现,日粮中添加柠檬酸,能降低十二指肠、盲肠pH值,抑制十二指肠、盲肠大肠杆菌生长,促进乳酸杆菌增殖。     

五味子提取物对肉仔鸡肠道微生物的影响

研究在肉仔鸡饲养中以五味子提取物作为添加剂对鸡肠道主要微生物的影响。试验选用1日龄的健康肉仔鸡120只,随机分为2个处理组,每组设4个重复,每个重复15只。采用单因子试验设计,于5日龄进行新生期五味子提取物的调控试验,五味子提取物添加量是0.125%。试验结果表明,日粮中添加五味子提取物能降低盲肠中大肠杆菌的数量(P<0.05),且有利于盲肠中乳酸杆菌的增殖。     

青贮玉米籽实对肉仔鸡生长性能、肠道菌群和肠道pH值的影响

试验旨在探讨青贮玉米籽实对肉仔鸡生长性能、肠道菌群和肠道pH值的影响,试验选用体质健康的1日龄AA肉鸡280羽,随机分成4组(空白对照组、试验1组、试验2组、试验3组),每组5个重复。分别饲喂添加了0、1.5%、2.5%、3.5%青贮玉米籽实的日粮,试验期42 d,试验结果表明:与空白对照组相比,2.5%青贮玉米籽实组42日龄重、日均采食量、平均日增重都显著提高(P<0.05),3.5%青贮玉米籽实组42日龄重、平均日增重显著提高(P<0.05),1.5%青贮玉米籽实组空肠中大肠杆菌显著降低,2.5%和3.5%青贮玉米籽实组空肠和盲肠中大肠杆菌显著降低(P<0.05),空肠和盲肠中乳酸杆菌显著提高(P<0.05),试验各组空肠和盲肠中pH值有下降的趋势,其中3.5%青贮玉米籽实组下降最显著(P<0.05)。试验表明饲料中添加青贮玉米籽实可提高肉仔鸡的生长性能,改善肠道内环境,综合考虑,日粮中添加2.5%青贮玉米籽实组效果较理想。     

酸化剂对肉仔鸡肠道微生物区系的影响

延胡索酸、柠檬酸是工业化养禽业中主要应用的饲料酸化剂.但酸化剂作为一种生长促进剂,其促进动物生长、提高畜禽饲料转化效率的作用机理至今尚未完全明了.一般认为,饲料酸化剂的作用机理与改善动物消化道微生物区系有关.此次研究旨在通过比较日粮中添加延胡索酸、柠檬酸对肉仔鸡肠道微生物区系的影响,探讨延胡索酸、柠檬酸促进肉仔鸡生长的作用机理.     

大豆寡糖对肉仔鸡肠道pH值和盲肠短链脂肪酸的影响

在玉米-大豆浓缩蛋白型低寡糖基础日粮中分别添加0、0.50%、1.00%或2.00%的大豆寡糖,研究了不同添加量大豆寡糖对肉仔鸡肠道pH值和盲肠短链脂肪酸的影响。选用192只1日龄AA肉公鸡,随机分成4个处理组,每个处理设6个笼(重复),每笼8只鸡。结果表明:大豆寡糖对18、36日龄肉仔鸡十二指肠和空肠食糜pH值的影响无明显规律,各处理组之间无显著性差异(P0.05);随着大豆寡糖水平的增加,盲肠食糜pH值呈下降的趋势(P0.05),1.00%大豆寡糖添加组18、36日龄肉仔鸡盲肠食糜pH值为最低水平,且显著低于对照组(P0.05)。低寡糖日粮中添加不同剂量大豆寡糖,大幅度增加肉仔鸡盲肠食糜中乙酸和短链脂肪酸总量的浓度(P0.05);添加1.00%或2.00%大豆寡糖,显著增加18日龄肉仔鸡盲肠食糜中丁酸占短链脂肪酸总量的摩尔百分比(P0.05)。     

柠檬酸对肉仔鸡屠宰性能的影响

试验选择180只1日龄健康AA+肉仔鸡,按日粮中柠檬酸添加剂量的不同(0%、0.75%、1.5%)分为3个日粮处理组,每个处理组6个重复,每个重复10只鸡,进行为期42d的饲养试验,旨在研究日粮中添加不同梯度的柠檬酸对肉仔鸡屠宰性能的影响。试验结果表明:添加0.75%柠檬酸可显著提高21日龄肉仔鸡的屠宰率(P0.05),极显著提高腿肌率(P0.01),胸肌率和全净膛率却显著降低于对照组(P0.05);添加1.5%柠檬酸可使21日龄肉仔鸡的全净膛率显著降低(P0.05),对其他屠宰性能指标无显著影响。     

酵母饲料对肉仔鸡肠道菌群及免疫机能的影响

用150只1日龄AA肉仔鸡，研究不同添加水平的酵母饲料对肉仔鸡肠道主要微生物及免疫机能的影响。试验结果表明，酵母饲料具有增强免疫机能，维持肠道微生态平衡，提高肉仔鸡体增生的效果。     

延胡索酸对肉仔鸡生产性能及肠道微生物区系的影响

延胡索酸是广泛应用于工业化养禽业中的一种饲料酸化剂，其促进动物生长，提高畜禽体重的作用机理至今尚未完全明了。一般认为饲料酸化剂的作用机理与改善动物消化道微生物区系有关。本研究旨在通过研究日粮中添加延胡索酸对肉仔鸡肠道微生物区系的影响，探讨延胡索酸促进肉仔鸡生长的作用机理。     

植酸酶对肉仔鸡生产性能、免疫功能及肠道微生物的影响

比较在营养水平相同的情况下,使用植酸酶日粮与普通日粮的鸡群在各阶段生产性能、淋巴细胞比率、免疫器官指数及盲肠内容物中大肠杆菌数量的变化。结果显示,添加植酸酶后,试验组较对照组平均日增重提高12%,其中雌性试验组与雌性对照组相比出栏体重增加396 g,平均日增重提高22.6%,差异极显著(P<0.01);植酸酶的使用能够有效降低盲肠大肠杆菌数量,雄性植酸酶组与雄性对照组相比在27,34,41日龄大肠杆菌数量降幅分别达到23%,34%和50%,而雌性植酸酶组与雌性对照组相比除34日龄外平均降幅达到50%。添加植酸酶后肉鸡巨噬细胞吞噬指数、免疫器官指数均出现不同程度下降。     

木聚糖酶对肉仔鸡后肠道微生物的影响

主要研究了小麦基础口粮添加木聚糖酶对肉仔鸡后肠道微生物的影响.将120只7日龄肉仔鸡分成2组,日粮分别添加0,0.1%木聚糖酶,饲喂至21日龄,研究木聚糖酶对肉仔鸡后肠道菌群数量变化的影响.结果表明,加酶未使同肠和盲肠乳酸杆菌、双歧杆菌和大肠杆菌数量发生显著变化.利用变性梯度凝胶电泳技术研究了木聚糖酶对肉仔鸡后肠细菌群体的影响.结果表明,加酶组回肠和盲肠的图谱比对照组条带相对较多,但差异不显著;组内个体间的图谱相似性比组问的相似性相对较大.木聚糖酶影响肉仔鸡后肠微生物数量和种群的作用效果不明显.     

Effects of citric acid and microbial phytase on amino acid digestibility in broiler chickens

1. Two experiments with growing chickens were carried out to study the effects of the inclusion of a microbial phytase (Natuphos 5000) and citric acid (CA) in maize-soybean-based diets on the performance and apparent ileal digestibility (AID) of crude protein (CP) and amino acids (AA). In both experiments the diets were formulated to contain the same amounts of energy and protein. 2. In the first experiment, data were analysed as a 2 x 2 factorial arrangement with two concentrations of available phosphorus (AP) from one day to 3 weeks of age (3.5 and 2.2 g/kg) and for 3 to 6 weeks (2.7 and 1.4 g/kg), and two inclusions of commercial phytase (0 and 500 FTU/kg) in each period. The AID of CP and dispensable and indispensable AA were not modified by the AP content of the diet. Addition of phytase improved the AID of CP and dispensable and indispensable AA only at low AP levels. 3. In the second experiment, data were analysed as a 3 x 2 factorial arrangement with three concentrations of citric acid (0, 20 and 50 g/kg) and two inclusions of commercial phytase (0 and 750 FTU/kg). Diets were formulated with deficient contents of AP (2.5 g/kg). Performance was not affected by commercial phytase addition. The addition of CA reduced the weight gain but did not modify the feed intake and gain:feed. In general, the AID of CP and dispensable and indispensable AA were not affected by CA addition. Commercial phytase increased the apparent ileal digestibility of crude protein but had no effect on AID of dispensable and indispensable AA. 4. In conclusion, the present work showed that microbial phytase enhanced AA digestibility in maize-soy-based diet only at very low AP concentrations, and that CA had no affect on the AID of CP and dispensable and indispensable AA. No synergism between CA and microbial phytase was detected.     

Effect of dietary citric acid on the performance and mineral metabolism of broiler

The objective of this study was to investigate the effect of dietary citric acid (CA) on the performance and mineral metabolism of broiler chicks. A total of 1720 Ross PM3 broiler chicks (days old) were randomly assigned to four groups (430 in each) and reared for a period of 35 days. The diets of groups 1, 2, 3 and 4 were supplemented with 0%, 0.25%, 0.75% or 1.25% CA by weight respectively. Feed and faeces samples were collected weekly and analysed for acid insoluble ash, calcium (Ca), phosphorus (P) and magnesium (Mg). The pH was measured in feed and faeces. At the age of 28 days, 10 birds from each group were slaughtered; tibiae were collected from each bird for the determination of bone mineral density, total ash, Ca, P, Mg and bone‐breaking strength, and blood was collected for the measurement of osteocalcin, serum CrossLaps^®, Ca, P, Mg and 1,25(OH)₂Vit‐D in serum. After finishing the trial on day 37, all chicks were slaughtered by using the approved procedure. Birds that were fed CA diets were heavier (average body weights of 2030, 2079 and 2086 g in the 0.25%, 0.75% and 1.25% CA groups, respectively, relative to the control birds (1986 g). Feed conversion efficiency (weight gain in g per kg of feed intake) was also higher in birds of the CA‐fed groups (582, 595 and 587 g/kg feed intake for 0.25%, 0.75% and 1.25% CA respectively), relative to the control birds (565 g/kg feed intake). The digestibility of Ca, P and Mg increased in the CA‐fed groups, especially for the diets supplemented with 0.25% and 0.75% CA. Support for finding was also indicated in the results of the analysis of the tibia. At slaughter, the birds had higher carcass weights and higher graded carcasses in the groups that were fed the CA diets. The estimated profit margin was highest for birds fed the diet containing 0.25% CA. Birds of the 0.75% CA group were found to have the second highest estimated profit margin. Addition of CA up to a level of 1.25% of the diet increased performance, feed conversion efficiency, carcass weight and carcass quality, but only in numerical terms. The addition of CA up to 0.75% significantly increased the digestibility of macro minerals, bone ash content, bone mineral density and bone strength of the broiler chicks. It may, therefore, be concluded that the addition of 0.75% CA in a standard diet is suitable for growth, carcass traits, macromineral digestibility and bone mineral density of broiler chicks.     

D-Xylose absorption capacity of broiler intestine in response to phytic acid

1?Dietary phytic acid (PA) reduces the apparent digestion and of dietary nutrients, increases the excretion of endogenous amino acids and minerals and reduces the concentration of blood glucose.

2?An experiment was conducted to examine the effect of phytic acid on the absorption capacity of the intestine in broiler chicken, using a D-xylose absorption test.

3?Three groups of ten 26-d-old apparently healthy broiler cockerels (Ross 308) were dosed with D-xylose solution (500 mg/kg BW, Group 1) or D-xylose solution + PA (330 or 660 mg/5 ml/bird, in groups 2 and 3), respectively. The plasma concentration of D-xylose was measured at 40-min intervals after ingestion of test materials, for a total of 160 min.

4?There was a quadratic correlation between the concentration of plasma D-xylose and time in all experimental groups (P < 0?001, R ²= 0?78, 0?80 and 0?81 for groups 1–3, respectively). Ingestion of PA at 660 mg reduced the concentration of plasma D-xylose by 21?6 and 10?5% at 40 and 80 min after ingestion of the test material, indicating a lower absorption of this sugar.

5?It was concluded that dietary phytates might affect the productive performance of chicken, at least partly, by disturbing the transport mechanisms involved in the absorption of nutrients.     

不同配比油脂对肉仔鸡小肠形态的影响

研究了日粮中添加不同配比油脂对肉仔鸡小肠形态的影响。试验选取324只1日龄AA肉鸡,随机分成6组,每组6个重复,每个重复9只。CON为对照组(饲喂基础日粮),SO组为正对照组(日粮添加豆油),LO组为负对照组(日粮添加猪油),COP、COC、COV组分别在日粮中添加以棕榈油为主的配比油脂、以椰子油为主的配比油脂和多种植物油配比的油脂,饲养至21日龄。结果:COP组的十二指肠和空肠的绒毛高度与隐窝深度的比值高于SO组(P<0.05),空肠的隐窝深度低于CON和SO组(P<0.05)。COC组的十二指肠绒毛宽度高于SO组和LO组(P<0.05),绒毛面积高于CON组、SO组和LO组(P<0.05);空肠的黏膜厚度高于LO组(P<0.05)。COV组的十二指肠绒毛高度高于CON组、SO组和LO组(P<0.05),十二指肠黏膜厚度高于CON组(P<0.05)。试验表明3种配比油脂均可从不同角度促进十二指肠和空肠的形态发育,且从提高绒毛表面积考虑,配比椰子油效果最好。     

谷氨酰胺对肉鸡肠道发育及小肠消化酶活性的影响

将180只1日龄AA肉仔鸡随机分成3组,设3个重复,每组60只,1组为对照组,2、3组为试验组,分别饲喂添加0%、0.2%、0.4%谷氨酰胺的基础日粮,试验期42 d,探讨了外源性谷氨酰胺对AA肉仔鸡小肠生长发育和消化道酶活性的影响.结果表明,在肉鸡饲料中添加外源性谷氨酰胺,能促进小肠的生长发育,显著增加肉鸡十二指肠、空肠和回肠重量、长度以及肠道指数(P＜0.05),提高小肠蛋白酶、脂肪酶、淀粉酶和胰蛋白酶活性(P＜0.05);谷氨酰胺的适宜添加剂量为0.2%.提示谷氨酰胺可作为肠道促生长添加剂在肉鸡饲料中使用,其适宜添加剂量为0.2%.     

添加柠檬酸对西门塔尔牛日粮养分消化率的影响

选用4头年龄4岁、体况良好、平均体重500k，装有永久性瘤胃瘘管的中国西门塔尔阉牛，采用4×4拉丁方设计，以混合精料和玉米秸秆为基础日粮．研究柠檬酸（0、100、200和300g／d）对日粮养分表观消化率的影响。结果表明：200g／d组精饲料干物质（DM）、粗脂肪（EE）、无氮浸出物（NFE）、中性洗涤纤维（NDF）和酸性洗涤纤维（ADF）较对照组显著提高（P〈0．05）。根据试验结果推断日粮中柠檬酸的适宜添加水平为200g/d。     

非淀粉多糖复合酶制剂对肉鸡肠道组织形态结构的影响

本试验旨在研究非淀粉多糖复合酶制剂对肉鸡肠道组织形态结构的影响。试验采用单因子随机分组试验设计,选取320只1日龄的科宝肉鸡商品代公雏,随机分到2个处理组,各处理组8个重复,每个重复20只鸡。处理1饲喂基础饲粮,处理2饲喂基础饲粮＋150mg/kgNSP复合酶制剂F。1~21d基础饲粮采用玉米-豆粕型饲粮,22~42d基础饲粮采用玉米-豆粕-DDGS型饲粮,低温制粒。试验结果为NSP复合酶制剂F对采食玉米-豆粕型饲粮的肉鸡21d肠道组织形态结构表现正负双面效应,能显著降低采食玉米-豆粕-DDGS型饲粮的肉鸡生长后期空肠肌层厚度,改善空肠的组织形态结构。     

Effect of Bacillus subtilis (DSM 17299) on performance,digestibility, intestine morphology,and pH in broiler chickens

This study investigated the effect of supplementation of a Bacillus subtilis strain DSM 17299 on broilers, including evaluation of performance, nutrient digestibility, intestinal morphology, and content pH. The treatments also were evaluated for economic value based on performance and dietary costs. Performance was improved for probiotic treated birds for wk one through 5 post hatch, and economic evaluation at wk 6 demonstrated that the addition of the probiotic reduced production costs. Total tract digestibility of dry matter (DM), crude protein (CP), and apparent metabolizable energy were improved in probiotic supplemented broiler chickens. Addition of the probiotic increased the pH of the intestinal content. The relative weight and relative length of the duodenum decreased by probiotic supplementation. Overall, B. subtilis DSM 17299 resulted in an improvement in performance and a decrease in production costs when fed to broiler chickens. The increases in nutrient digestibility of birds fed the B. subtilis DSM 17299 correlate well with the increased performance noted over the same growing periods.