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。     

早期限饲对肉仔鸡的影响

遗传育种选育和营养水平的改进,在使肉仔鸡生长速度不断提高的同时带来了一系列负面影响,如脂肪沉积、代谢性疾病、骨骼疾病、死亡率增加。早期限饲在改善这些问题上有一定的作用。本文综述了早期限饲对肉仔鸡的生产性能和健康状况等影响,并对早期限饲的进一步研究方向进行了展望。     

外源性脂肪乳化剂饲喂肉仔鸡的试验

选取360只21日龄的AA肉仔鸡,随机分为3组,每组设4个重复,每重复30只。对照组饲喂基础日粮,试验1组在基础饲粮中添加250mg/kg脂肪乳化剂,试验2组添加500mg/kg脂肪乳化剂。试验分2阶段进行,22～35日龄饲喂I期日粮,35～49日龄饲喂II期日粮,每期结束时进行生长性能统计,并于每期试验结束前2d收集鸡群粪便进行消化率测试。试验结果表明,外源性脂肪乳化剂能有效提高肉仔鸡生产性能和脂肪消化率,平均日增质量提高7.5%(P<0.05),料重比下降6.1%(P<0.05),脂肪利用率提高6.8%(P<0.05)。     

滇池凤眼莲饲喂肉仔鸡试验的研究

在肉仔鸡玉米－豆粕－鱼粉型饲粮中添加３％、５％、７％凤眼莲干粉替代部分饼粕和麸皮,用艾维茵肉仔鸡经过４０ｄ饲喂试验,结果平均每只增重,对照组２．０ｋｇ,３％凤眼莲组１．９９３ｋｇ,５％凤眼莲组１．９３４ｋｇ,７％凤眼莲组１．９０２ｋｇ,各组间增重差异不显著（Ｐ＞０．０５）。研究结果表明,在肉仔鸡饲粮中添加７％以内的凤眼莲是安全可行的。     

日粮中添加不同柠檬酸水平对肉仔鸡生长的影响

为研究日粮柠檬酸水平对肉仔鸡生产性能的影响,选280只麻黄商品肉仔鸡,随机分为4组,采用天康三黄肉鸡料（料号610s和613s）作为基础日粮,试验组各组柠檬酸添加水平分别是0、0.25%、0.5%、1%,试验期为5周。结果表明,0.5%的柠檬酸添加组,鸡增重最快,比对照组提高4%（P〉0.05）,添加0.25%、0.5%的柠檬酸鸡的饲料报酬最高,比对照组提高3.4%（P〉0.05）、4.1%（P〉0.05）。从试验结果,添加柠檬酸对日粮有机物质的消化率有影响,其中添加0.5%柠檬酸鸡的蛋白质消化率最高（P〈0.05）,Ca.P的消化率试验组显著高于对照组（P〈0.05）。结论,肉鸡日粮添加0.5%柠檬酸对其生长有一定促进作用。     

大豆脂肪酸钙代替油脂饲喂肉仔鸡的试验

脂肪酸钙是反刍动物日粮中常用的过瘤胃脂肪营养来源,由于其在瘤胃中不易被微生物降解,可避免脂肪对瘤胃微生物分解纤维素的干扰。大豆脂肪酸钙是由大豆油脂水解所得的脂肪酸经皂化反应制取的脂肪酸钙盐,它比用棕榈油或动物油制造的脂肪酸钙含有更丰富的必需脂肪酸,除了用于反刍动     

饲喂茶叶粉对肉仔鸡的影响研究

本试验通过添加1.5%和4.5%的茶叶粉对肉仔鸡的生产性能和抗病性的影响,结果表明：添加1.5%、4.5%的茶叶粉可显著提高肉仔鸡免疫器官的重量和指数,且作用效果随添加量的增多而加强;而试验组体重均较对照组偏低,三组鸡全期日增重差异均显著（P〈0.05）,对照组饲料转化率较理想,与其他两组差异不显著（P〉0.05）,试验组半净膛率、腹脂率与对照组比较差异显著（P〈0.05）,试验组间差异不显著,随添加量增多,胸、腿肉比率随之增大,试验组腹脂率明显低于对照组;Ⅱ组对营养物质的吸收代谢较好,而Ⅰ组对各营养物质的沉积效果较为理想。     

松萝酸对AA肉仔鸡生产性能与屠宰性能的影响

选择健康的1日龄AA肉仔鸡225只,随机分成5组,即阴性对照组(基础日粮)、抗生素组(基础日粮+0.3 g/kg那西肽和0.25 g/kg硫酸黏杆菌素预混剂)及0.003%松萝酸(USA)组(基础日粮+0.003%USA)、0.004%USA组(基础日粮+0.004%USA)、0.005%USA组(基础日粮+0.005%USA),每组45只肉仔鸡(每组设3个重复,每个重复15只),饲养周期为42d。分别在1、7、14、21、28、35、42日龄对各组肉仔鸡活体重、投料量、剩料等进行称量,用于生产性能测定;同时试验结束当天(即第42天清晨),从每个重复组随机抽取3只肉仔鸡进行屠宰用于测定其屠宰性能。结果表明:0.003%USA组平均活体重、平均日增重分别比阴性对照组、抗生素组、0.004%USA组、0.005%USA组高4.26%(P0.05)、2.03%(P0.05)、5.41%(P0.05)、12.43%(P0.05)和6.08%(P0.05)、0.75%(P0.05)、11.25%(P0.05)、14.02%(P0.05);从平均日采食量、料重比可以看出,0.003%USA组较阴性对照组、抗生素组、0.004%USA组、0.005%USA组分别降低了1.56%(P0.05)、3.92%(P0.05)、0.88%(P0.05)、0.90%(P0.05)和10.19%(P0.05)、2.08%(P0.05)、10.19%(P0.05)、12.96%(P0.05);添加松萝酸试验组的存活率显著高于阴性对照组。不同水平的松萝酸对肉仔鸡主要胴体指标的影响表明,0.003%USA组较抗生素组宰前活重、屠体重、半净膛重、全净膛重、腿肌重有一定程度的降低,但高于阴性对照组,差异不显著(P0.05),而0.004%USA组、0.005%USA组对肉仔鸡屠宰性能基本无改善作用,但0.003%USA组较抗生素组腹脂率下降了8.17%(P0.05)。说明添加0.003%松萝酸可在一定程度上促进肉仔鸡的生长发育,提高饲料转化率与屠宰率及一定程度上提高了肉仔鸡的存活率。     

采用肉仔鸡三阶段饲喂法效果好

随着育种工作的进展,商品肉仔鸡的生长速度每年以1％-1.5％快速递增。所以目前的肉仔鸡饲喂法已不能适应这种快速生长的特点,笔者根据自己的生产体会,把肉仔鸡的生长期分为三个阶段,     

柠檬酸对肉仔鸡肠道pH值及肠道微生物的影响

长期以来的大量研究证实,胃肠道微生物大多都是有益的并与动物存在着共生关系,这种共生关系表现在畜禽消化道为微生物提供适宜生长的环境,反过来微生物提供了动物所需要的某些营养物质。尽管对消化道微生物作用的认识还不全面,但已取得一些共识：消化道微生物参与机体物质代谢、营养转化和合成,影响营养物质的分解吸收（康白,１９８８）。同时饲料是影响消化道微生物区系建立的主要环境因素之一。本试验拟通过对肉仔鸡十二指肠、盲肠３种正常菌群的观察来研究柠檬酸对肠道正常微生物的影响。１材料与方法１．１试验设计和日粮试验采用…     

植酸酶和柠檬酸对肉鸡生产性能及钙、磷利用率的影响

植物籽实及谷物中60%～80%的磷以植酸磷的形式存在。家禽消化道缺乏水解植酸的酶对植酸磷的利用率很低。业已证明,添加植酸酶可提高植酸磷、Ca、蛋白质等养分的利用,减少粪磷对环境的污染。肉鸡日粮中添加450U/kg的植酸酶,可将日粮的CP水平降低一个百分点而不影响生长性能、胴体品质和AA的消化率,同时可使氮排出量减少10%(Kemme等,1995)。磷消化试验和长期饲养试验的结果表明,300FTU/kg的植酸酶相当于磷酸一钙中的1.0g磷。肉鸡日粮中添加300FTU/kg植酸酶,日粮磷(无论是TP或AP)含量应降低0.1%,Ca水平应减低0.1个百分点。近年来的研究…     

植酸酶、柠檬酸和碳酸化合物酶对肉鸡生长性能和养分利用率的影响

文章旨在研究低磷、低钙水平日粮添加植酸酶、柠檬酸和碳水化合物酶对1~21 d肉鸡生长性能及养分消化率的影响。试验选择1日龄肉仔鸡576只,随机分为6组,每组4个重复,每个重复24只鸡。试验共分为6种日粮,阳性对照组日粮(正常钙磷水平)、阴性对照日粮(低磷、低钙)、阴性对照日粮+600 IU/kg植酸酶,阴性对照日粮+600 IU/kg植酸酶+5 g/kg柠檬酸,阴性对照日粮+600 IU/kg植酸酶+500 mg/kg复合碳水化合物酶,阴性对照日粮+600 IU/kg植酸酶+5 g/kg柠檬酸+500 mg/kg复合碳水化合物酶。试验共开展21 d。结果显示:阳性对照组肉鸡日增重和采食量显著高于阴性对照组(P<0.05);植酸酶组添加碳水化合物酶较单独添加植酸酶组显著提高了肉鸡的日增重(P<0.05);植酸酶+碳水化合物酶较阴性对照组显著改善了料肉比(P<0.05)。阳性对照组较阴性对照组显著提高肉鸡胫骨灰分含量(P<0.05);植酸酶组显著提高了总磷、有效磷和植酸磷的回肠表观消化率(P<0.05),同时植酸酶组添加柠檬酸或碳水化合物酶进一步提高了总磷和植酸磷的回肠表观消化率(P<0.05)。阴性对照组添加植酸酶显著提高了表观代谢能及干物质、总能、氮和总磷的表观沉积量(P<0.05),而植酸酶组添加碳水化合物酶提高了干物质和总磷表观沉积量(P<0.05)。结论:在本试验条件下,低磷、低钙水平日粮添加植酸酶和碳水化合物酶改善了肉鸡生长性能、提高了营养物质的消化率和沉积量,而植酸酶日粮添加柠檬酸可以改善营养物质消化率和沉积量。     

植酸酶和柠檬酸对肉鸡生产性能及钙、磷利用率的影响

试验以正常营养水平饲粮为对照 ,研究在低营养水平饲粮中添加植酸酶 (0、 30 0g/t)、柠檬酸 (0、 0 5% )对肉鸡生产性能和钙、磷利用率的影响。试验用 2 2 5羽 1日龄黄羽肉鸡随机分为 5个处理 ,每处理 3个重复 ,每重复 1 5只鸡进行 6周试验。结果饲粮营养水平降低 6 %可导致肉鸡日增重 (ADG)和饲料利用率下降 (P <0 0 5) ;在低营养水平日粮中 ,添加 30 0g/t植酸酶、 0 5 %柠檬酸 ,ADG和料肉比 (F/G)与正常营养水平饲粮组差异不显著 (P >0 0 5) ;各处理组的血清Ca、P、AKP活性及胫骨Ca、P差异不显著 (P >0 0 5) ;腿病发生率各处理组差异不显著 (P >0 0 5)。添加 30 0g/t植酸酶、 0 5 %柠檬酸的处理组P排泄量显著低于对照组 (P <0 0 5)。植酸酶与柠檬酸合用能进一步提高生产性能和钙、磷利用率 ,能达到正常营养水平饲粮的效果。植酸酶与柠檬酸合用存在协同效应     

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.     

Effect of high-dose phytase and citric acid,alone or in combination,on growth performance of broilers given diets severely limited in available phosphorus

1. Two trials were conducted to evaluate the effect of high-dose phytase alone or in combination with citric acid (CA) in the diet severely limited in available phosphorus (P) on performance, plasma P and plasma Ca of broilers from 22 to 42 d of age.

2. In Trial 1, 297 21-d-old female chicks were placed into 27 pens and allocated to 9 maize-soybean meal-based dietary treatments, which were a positive control [PC, 4.23 g/kg non-phytate P (NPP)] and 8 negative control (NC, 1.35 g/kg NPP) groups consisting of two concentrations of CA (0 and 20 g/kg) and 4 concentrations of phytase (0, 1000, 2000 and 4000 U/kg) in a 2 × 4 factorial arrangement. In Trial 2, 192 21-d-old male chicks were placed into 24 pens and allocated to 6 wheat-canola meal-based dietary treatments, which were a PC (4.2 g/kg NPP), a NC (1.68 g/kg NPP) and 4 NC groups consisting of two concentrations of CA (0 and 20 g/kg) and two concentrations of phytase (2000 and 4000 U/kg) in a 2 × 2 factorial arrangement.

3. In both trials, birds fed on the PC had significantly higher average daily gain (ADG), average daily feed intake (ADFI), plasma P and lower feed conversion ratio (FCR) and plasma Ca than those of birds fed on the NC. CA supplementation significantly increased ADG and ADFI. There was a significant interaction between CA and phytase on plasma P where CA improved the effect of phytase on plasma P. In Trial 1, phytase addition improved ADG, ADFI, FCR and plasma Ca linearly.

4. Briefly, this research showed the interaction effect between CA and phytase on plasma P when broilers were fed on diets based on maize-soybean meal or wheat-canola meal. The results showed that CA supplementation lowered the concentration of phytase that is needed in low NPP diets to increase plasma P.     

Effect of citric acid and calcium on the bioavailability of orally-administered oxytetracycline in piglets

The bioavailability of orally given oxytetracycline in dependence on calcium (0.7% and 1.4% calcium, respectively) and citric acid content in feed was examined in piglets (9.9 +/- 0.9 kg body weight). In the first trial no citric acid was added to the two feeds, in the second trial 1.5% citric acid was added. In both trials each piglet received an i/v-injection of oxytetracycline (dosage 10 mg/kg body weight) and an oral dose of oxytetracycline (40 mg/kg body weight). The blood samples, taken in definite time intervals, were analysed by a microbiological assay. With these results the kinetic parameters and the bioavailability were calculated. The results of the i/v-trials were identical. The kinetic parameters C1 = 14.91 micrograms/ml, lambda 1 = 3.46 h-1, Cz = 7.49 micrograms/ml and lambda z = 0.19 h-1 describe the graph after i/v-application. The calcium content of the feed had no significant influence on the kinetic parameters after p/o-application, but the piglets receiving citric acid showed a significant higher maximum concentration (Cmax). The bioavailability of orally given oxytetracycline was significantly (26%) increased by the citric acid content. In spite of the citric acid the bioavailability only came to 4.9%.     

玉米赤霉烯酮对肉鸡血液生化指标、肝脏氧化损伤及毒素残留的影响

试验旨在研究玉米赤霉烯酮(ZEA)对肉鸡血清指标、肝脏氧化损伤及毒素残留的影响。将120只1日龄肉鸡随机分成2组,每组设6个重复,每个重复10只。对照组饲喂基础日粮,攻毒组在基础日粮中添加2 mg/kg的ZEA。结果表明,ZEA攻毒使肉鸡血清总蛋白和白蛋白显著降低,天冬氨酸转氨酶、丙氨酸转氨酶、碱性磷酸酶显著上升;ZEA对血清IgA、IgM、IgG及细胞因子IL-2、IL-5、TNF-α水平无显著影响;ZEA使肉鸡肝脏总超氧化物歧化酶和谷胱甘肽过氧化酶活性降低,还原性谷胱甘肽含量下降,丙二醛含量升高;ZEA攻毒组肉鸡肝脏的残留量显著上升。结果提示,ZEA可影响肉鸡血清代谢物水平,造成肝脏氧化损伤,提高肝脏中残留量。     

日粮中添加柠檬酸对雏鸡生长发育的影响

在雏鸡日粮中添加不同水平的柠檬酸,观察其对罗曼公雏生长发育的促进作用。结果表明,0．1％柠檬酸添加水平有提高生长速度和饲料转化率的作用。