1～21日龄黄羽肉鸡钠、氯的需要量

本试验旨在通过研究饲粮不同钠、氯水平对黄羽肉鸡生长性能、排泄物含水率、血清指标、肠道钠-葡萄糖共转运载体1(SGLT1)和钠/氢交换载体2(NHE2)mRNA表达量等的影响,探讨1~21日龄阶段黄羽肉鸡钠和氯的需要量及其作用机理。试验选用1日龄健康、发育良好的快大型岭南黄羽肉公鸡共1 200只,根据体重随机分成5个组,每组6个重复,每个重复40只鸡。对照组采用玉米-豆粕型基础饲粮(无额外钠、氯添加),其余各组都以钠、氯含量比1∶1设梯度,通过食盐与碳酸氢钠等量取代部分沸石粉使饲粮钠与氯含量均分别为0.1%、0.2%、0.3%和0.4%,试验期间试鸡自由采食和饮水。试验结果显示,饲粮补充钠、氯显著提高了平均日增重、平均日采食量、平均日饮水量和排泄物含水率(P0.05),显著降低了料重比和死亡率(P0.05),其中平均日增重随饲粮钠、氯水平的提高呈二次折线升高(R2=0.966,P=0.009),排泄物含水率随饲粮钠、氯水平的提高呈先升高后降低的二次曲线变化(R2=0.954,P=0.046);饲粮补充钠、氯显著提高了血清渗透压(P0.05),显著降低了血清尿酸、葡萄糖、总胆固醇和甘油三酯含量(P0.05),对血清胆囊收缩素、胃饥饿素和生长激素含量无显著影响(P0.05);饲粮钠、氯水平均为0.2%、0.4%组十二指肠NHE2 mRNA表达量和钠-钾ATP(Na+-K+-ATP)酶活性显著低于对照组(P0.05);饲粮钠、氯水平为0.2%组回肠SGLT1 mRNA表达量显著高于对照组和0.4%组(P0.05)。结果提示,本试验条件下,以生长性能为评定指标,根据方差分析和多重比较得到,1~21日龄阶段快大型黄羽肉鸡饲粮适宜钠、氯水平均为0.2%;通过非线性回归模型估测得到,饲粮适宜钠、氯水平均为0.14%。     

生长抑素抑制剂——半胱胺促进肉用仔鸡生长的研究

本研究室的工作已经证明,半胱胺(Cysteamine,CS)能加速大鼠、幼兔的生长。本试验进一步观察CS对红布罗肉用仔鸡生长的作用。21日龄仔鸡30只分为对照和CS实验两组,CS每周口服一次(剂量:100mg/kg体重)。40日后,CS组仔鸡增重比对照组提高5.3％(1299克对1368克)(P<0.05)。CS口服不改变仔鸡的采食量,但料肉比降低了5.7％;血清生长抑素水平明显降低(102.3对43.5pg/ml)(P<0.01),血脉氮含量也显著低于对照组(P<0.05)。 32日龄52只仔鸡进行重复试验,CS实验组每5天给药一次(80mg/kg体重)。58日龄时CS组仔鸡增重比对照组提高7.9％(913.7克对985.5克)(P<0.025),胴体重超过5.5％(P<0.05),腹脂/胴体重比值降低了20.5％。上述结果表明,CS能够抑制SS水平,促进仔鸡生长,并提高饲料转化率,减少体内脂肪含量,改善胴体品质,这些作用均具有一定的生产价值。     

Metabolizable and Net Energy Values of Expanded Cottonseed Meal for Laying Hens and Broiler Chickens

Three experiments were conducted to determine the metabolizable energy (ME) and net energy (NE) values of expanded cottonseed meal (ECSM) for broilers aged 14–16 days (Experiment 1), broilers aged 28–30 days (Experiment 2), and 45-week-old Hy-Line Brown hens (Experiment 3). Reference diets based on corn-soybean meal were used to meet the nutritional needs of the birds. The test diets contained ECSM as basis, which was used to replace 18.5% of the gross energy-yielding ingredients from the reference diet. The birds were fed a commercial feed before the experimental period. After the dietary adaptation period, six birds per replicate (Experiment 1) and two birds per replicate (Experiments 2 and 3) for each treatment group were placed in an individual open-circuit respiratory calorimetry chamber for 3 days. Daily O₂ consumption and CO₂ production were recorded, and excreta samples were collected. The ME and NE values of ECSM were determined using the substitution method. The apparent metabolizable energy (AME) values of ECSM for experiments 1, 2, and 3 were 2605.85, 2178.31, and 2782.60 kcal/kg of dry matter (DM), respectively. The NE values were 1655.23, 1196.64, and 1538.19 kcal/kg of DM, respectively. The NE:AME ratios of ECSM were 63.52%, 54.93%, and 55.29%, respectively. Our data showed that the ME and NE values of ECSM differed across various growth stages and types of chickens. These results demonstrate that the appropriate ME and NE should be used in the design of different feed formulas for specific growth stages and types of chickens.     

An evaluation of apramycin soluble powder for the treatment of naturally acquired Escherichia coli infections in broilers

During 1983, a series of trials was carried out in Greece, Italy and Jordan, to test the efficacy of the aminocyclitol antibiotic apramycin as a treatment for naturally acquired Escherichia coli infections in broilers. The trials involved a total of 40,389 broilers, 27-39 days of age, in twelve houses at eight different production sites. Three levels of apramycin medication were evaluated: 125, 250 and 500 mg activity/litre drinking water, administered for five consecutive days. Treatment was only initiated after disease had been confirmed by laboratory examination of dead birds. Not all treatments were evaluated in every house. However, each house contained a group of unmedicated birds as controls, while the remaining birds were allocated to one or more apramycin treatment groups. There was a reduction in mortality and an improvement in the final weight and the economic feed conversion ratio in all three treatment groups. The data presented provide support for the use of apramycin sulphate administered in the drinking water for the treatment of E. coli infections in broilers.     

炎热季节肉鸡生产使用湿帘降温系统效果评价

选取21日龄科宝(Cobb)肉鸡120只,随机均分成两组(每组一个重复,每重复30只),分别饲养于湿帘降温肉鸡舍(试验组)和半开放式普通肉鸡舍(对照组),研究炎热季节肉鸡生产使用湿帘降温系统的效果.结果表明,试验组比对照组日增重、采食量、饲料报酬分别提高24.69%,8.34%,12.89%(P＜0.05),利润增加147%;投资湿帘降温系统的损益平衡点为饲养量5829只.     

Effect of different non-chloride sodium sources on the performance of heat-stressed broiler chickens

1. One hundred and eighty 1-d-old broiler chicks were used to evaluate the effect upon broiler performance during severely hot summer months of three different sodium salts: sodium bicarbonate (NaHCO3), sodium carbonate (Na2CO3) and sodium sulphate (Na2SO4), in starter and finisher diets having an identical electrolyte balance (DEB) of 250 mEq/kg. 2. The non-chloride sodium salts were added to contribute the same amount of sodium and were substituted at the expense of builder's sand in the basal diets containing common salt (NaCl) as Na and Cl source. 3. Each diet was fed to three experimental units having 15 chicks each until 42 d of age. Severe heat-stress conditions, maintained in the rearing room, were indicated by high average weekly room temperature (minimum 29.3 degrees C; maximum 38.0 degrees C). 4. Diets containing sodium salts gave better body weight gain, feed intake and feed to gain ratio than the control diet. Sodium salts also enhanced water intake as well as water to feed intake ratio. This effect was more pronounced in broilers fed NaHCO3 supplement (with NaCl in the basal diets). 5. The increased water intake resulted in lower body temperature in heat-stressed birds fed NaHCO3 supplemented diet than in birds fed other sodium salts. A lower mortality rate was noted with NaHCO3 (15.15%), Na2CO3 (13.64%) and Na2SO4 (15.15%) supplements than with the control (33.33%) treatment. 6. Better carcase and parts yield were observed in sodium supplemented broilers. Sodium salts reduced the alkalotic pH and enhanced the blood sodium content, which ultimately improved the blood electrolyte balance and overall performance of heat-stressed broilers. 7. Supplementing broiler diets with sodium salts improved the live performance of heat-stressed broilers and better productive performance was noted with NaHCO3 than other sodium supplements.     

The detrimental effect of vaccinating parentally immune broilers with a modified liver virus vaccine for infectious bursal disease

The experiment involved 392,955 broilers from breeders vaccinated with a commercially available killed infectious bursal disease (KIBD) virus vaccine (Treatments 1 and 2) and 373,371 broilers from breeders not vaccinated with a KIBD virus vaccine (Treatment 2). The broilers from the KIBD-vaccinated breeders were divided into two treatment groups: Treatment 1 consisted of 209,457 broilers and Treatment 2 consisted of 183,498 broilers. Treatment 2 broilers were vaccinated at 10 days of age intraocularly with a commercially available modified liver infectious bursal disease virus (IBD-MLV) vaccine. Broilers in all three treatments were raised on commercially contracted farms serviced by the same company representative. Broiler performance was based on mortality, body weight, feed efficiency, condemnations, and how each farm ranked with respect to contract settlements. Compared with birds in Treatments 2 and 3 respectively, Treatment 1 broilers had 1.65% and 0.89% less mortality; 0.22 lbs. and 0.09 lbs. increased weight per bird; 0.03 and 0.03 increased feed efficiency; 0.09% and 0.32% fewer air sacculitis condemnations; and 0.57% and 0.83% fewer total condemnations. Treatment 1 broilers ranked in the top 37%; Treatment 2 ranked in the bottom 36%; and Treatment 3 ranked in the lower 57% of contract settlements for all broilers processed. The results clearly showed that Treatment 1 broilers outperformed Treatment 2 amd 3 birds and that the IBD-MLV vaccine had a detrimental effect on Treatment 2 broilers.     

饲喂发酵饲料对肉鸡生长性能、养分利用率、肠道健康和肉品质的影响

【目的】本试验旨在研究肉鸡生长前期(1～21日龄)饲喂发酵饲料对其生长性能、养分利用率、肠道健康和肉品质的影响。【方法】选用1日龄爱拔益加肉鸡公鸡240只,随机分入4个处理组,每组6个重复,每个重复10只鸡。4组肉鸡生长前期(1～21日龄)分别饲喂添加0、5%、10%、15%发酵饲料的试验饲粮,生长后期(22～42日龄)均饲喂不含发酵料的基础饲粮,试验期为42 d。试验第21和42天时,测定肉鸡的1～21日龄、22～42日龄和1～42日龄生长性能、19～21日龄和40～42日龄养分利用率、42日龄肠道菌的数量和42日龄肉品质等指标。【结果】与对照组相比,饲喂10%发酵饲料显著降低肉鸡1～21日龄料重比(P<0.05);饲喂15%发酵饲料显著提高肉鸡1～42日龄平均日增重和平均日采食量(P<0.05),显著提高19～21日龄肉鸡干物质利用率和能量代谢率(P<0.05)。前期饲喂发酵饲料对42日龄肉鸡的盲肠菌群数量影响不显著(P>0.05)。与对照组相比,饲喂发酵饲料显著降低42日龄肉鸡肌肉中胆固醇含量(P<0.05)。【结论】生长前期饲喂10%的发酵饲料显著...     

Quantitation of intestinal D-xylose absorption in normal broilers and in broilers with pale-bird syndrome

A micromethod was used in order to quantitate intestinal D-xylose absorption in young and extremely small birds. This test was performed in broilers collected from two farms from which birds were extremely uneven in body size and were passing poorly digested or undigested feed. A similar syndrome had been seen on all grow-outs during the 6 months before this investigation. Broilers were also collected and tested from three farms where no clinical signs of disease were seen. D-Xylose absorption peaks and curves for normal broilers closely resembled those observed in normal humans. Mean plasma D-xylose concentrations for virus-infected broilers and for broilers with pale-bird syndrome were consistently lower than concentrations for normal broilers (P = 0.009). Reoviruses, small coronavirus-like particles, small round virus particles, and abundant bacterial flagellar fragments were seen in fecal samples from broilers with pale-bird syndrome. Production performance was lowest on farms showing clinical signs of this syndrome.     

二次回归正交旋转组合设计优化21～42日龄肉仔鸡胆碱和蛋氨酸需要量

本试验以低胆碱、低蛋氨酸饲粮为基础饲粮,通过两因子二次回归正交旋转组合设计,对21～42日龄肉仔鸡胆碱和蛋氨酸需要量进行研究.试验选用21日龄爱拔益加(AA)肉仔鸡480只,随机分为12个组,其中1～8组为试验组,9～12组为中心组,每组4个重复,每个重复10只鸡,公母各占1/2.分别以胆碱和蛋氨酸为自变量,以反映肉仔鸡生长性能和屠宰性能的各项指标为因变量拟合回归方程,估计21 ～ 42日龄肉仔鸡胆碱和蛋氨酸的需要量.试验期21 d.结果表明:胆碱和蛋氨酸水平对21～42日龄肉仔鸡的平均日采食量、料重比、腹脂率和肝脂率有显著影响(P＜0.05).当胆碱水平在860～1 120mg/kg时,肉仔鸡平均日采食量随着蛋氨酸水平的增加而升高,蛋氨酸水平增至0.40％后,继续增加对平均日采食量的改善作用不明显;蛋氨酸水平在0.35％～0.42％,胆碱水平在860 ～1 120mg/kg时,肉仔鸡的料重比达到最低值;蛋氨酸水平在0.30％～0.47％时,随着胆碱水平的增加肉仔鸡腹脂率呈下降趋势;当蛋氨酸水平在0.30％ ～0.40％,胆碱水平在1 000 ～1 400mg/kg时,肉仔鸡肝脂率随着胆碱水平的增加和蛋氨酸水平的降低呈下降趋势.在本试验条件下,当胆碱水平为990 ～1 030mg/kg,蛋氨酸水平为0.40％ ～0.43％时,肉仔鸡可达到最佳生长性能;当胆碱水平为1 780～1 880 mg/kg,蛋氨酸水平为0.37％ ～0.38％时,肉仔鸡可达到最佳屠宰性能.     

Comparison of three different diets for organic broilers: effects on performance and body condition

1. The aim of this study was to assess the feasibility of 100% organic feed for organic broilers by comparing it with 80% organic feed (situation at the time of the experiment; 2004) and 95% organic feed (alternative). 2. Diets were optimised for nutritional value, allowing a maximum 10% increase in feed price when using 100% organic feedstuffs. This could only be achieved at the expense of the methionine content. 3. The birds were reared from 0 to 3 weeks of age in a broiler house in three groups of 500 broilers each on either an 80, a 95 or a 100% organic starter diet. At 3 weeks of age, they were transferred to 15 pens with an outdoor run. Each treatment group of 500 birds was divided into 5 groups of 95 and given an 80, a 95 or a 100% organic finisher diet. 4. Broilers receiving 100% organic feed reached a lower body weight and grew more slowly than those receiving 95% organic feed, mainly because of a lower feed intake. 5. Broilers on 95 or 100% organic feed had a higher incidence of breast blisters than broilers receiving 80% organic feed. 6. The cost price for meat from broilers that received 80% organic feed was euro1.83 per kg live weight. The cost prices for broilers that received 95 and 100% organic feed were euro1.84 (+0.8%) and euro1.93 (+5.4%) per kg live weight, respectively. 7. In conclusion, 95% organic feed led to a better performance than 100% organic feed in this study. Probably, the lower methionine content in the 100% organic feed negatively affected performance. The results for 95% organic feed were similar to 80% organic feed, except for a higher incidence of breast blisters.     

Comparison between a live, attenuated anticoccidial vaccine and an anticoccidial ionophore, on performance of broilers raised with or without a growth promoter, in an initially Eimeria-free environment.

An experiment was carried out to study the effects of vaccination with Paracox, a live, attenuated vaccine against avian coccidiosis, on broilers isolated from extraneous Eimeria parasites. The study involved 3200 broiler chickens raised in floor pens similar to commercial conditions, but in an initially Eimeria-free environment. Forty percent of the chickens were vaccinated at 3 days of age and given either a basal unmedicated feed or a feed supplemented with the feed antibiotic virginiamycin. Unvaccinated birds were given either the basal feed or feed supplemented either with virginiamycin or the anticoccidial ionophore narasin. At slaughter at 36 days of age vaccinated birds had a lower live weight than non-vaccinated birds. The difference was 4.6% in unmedicated, and 6.0% in virginiamycin medicated chickens. Feed conversion ratio at slaughter was 2.5% higher for unmedicated vaccinated birds, and 1.3% higher for virginiamycin medicated vaccinated birds, compared to respective non-vaccinated groups. There was no significant difference in overall performance of unvaccinated birds given narasin as compared to virginiamycin. At 10 days post vaccination vaccinated birds had a higher number of Clostridium perfringens in the caeca, but there was no difference thereafter. Throughout the experiment, caecal clostridial counts were considerably higher in vaccinated unmedicated birds than in unvaccinated birds given narasin. The number of oocysts shed in the vaccinated groups was very low, but during a subsequent challenge with E. maxima and E. tenella the birds' immunity was found to be satisfactory.     

1～21日龄雌性肉仔鸡表观回肠可消化色氨酸需要量评定

本试验旨在研究1～21日龄雌性肉仔鸡表观回肠可消化色氨酸需要量及饲粮色氨酸水平对肉仔鸡肉品质、抗氧化指标和免疫指标的影响。试验选取480只1日龄雌性商品代肉雏鸡,随机分成5个处理,每个处理8个重复,每个重复12只鸡。采用含0.170%色氨酸的玉米-豆粕-玉米蛋白粉型基础饲粮,分别在其中添加0、0.021%、0.042%、0.063%和0.084%晶体L-色氨酸,使饲粮色氨酸水平分别为0.170%、0.191%、0.213%、0.234%和0.248%。测定1～21日龄肉仔鸡生产性能、胸肌品质、抗氧化指标、免疫指标和21～25日龄肉仔鸡氨基酸表观消化率和表观回肠消化率。结果表明:饲粮色氨酸水平显著影响1～21日龄肉仔鸡采食量及增重(P<0.05),采食量及增重与饲粮表观回肠可消化色氨酸水平呈现二次曲线关系(P<0.05)。1～21日龄肉仔鸡获得最大增重的饲粮表观回肠可消化色氨酸水平为0.176%,表观回肠可消化色氨酸摄入量为68.15 mg/d。与饲粮色氨酸水平0.170%相比,饲粮色氨酸水平0.213%及0.248%可显著降低肉仔鸡胸肌丙二醛含量、肝脏总超氧化物歧化酶活性和血清谷丙转氨酶活性(P<0.05),饲粮色氨酸水平0.248%可显著提高肉仔鸡屠宰后45 min胸肌pH、肠道总分泌型免疫球蛋白A浓度及血清总免疫球蛋白A浓度(P<0.05)。由此可知,1～21日龄雌性肉仔鸡获得最大增重的表观回肠可消化色氨酸需要量为0.176%(68.15 mg/d)。提高饲粮色氨酸水平可减轻肉仔鸡组织细胞脂质过氧化损伤,降低屠宰后肉仔鸡胸肌酸度,改善肉仔鸡肠道黏膜免疫和体液免疫能力。     

颗粒饲料和粉状饲料饲养肉鸡比较试验

采用颗粒饲料和粉状饲料对400只AA肉鸡进行饲养试验,试验分为两组,每组各200只,设一个重复.试验结果表明饲喂颗粒饲料的平均日增重为54.65 g,比粉料组的平均日增重47.67 g高出14.6%.对各周龄雏鸡活重的比较表明,颗粒饲料组极显著优于粉料组(P《0.01).但两组的死亡率无显著差异.随着日龄的增加,料重比呈现增大的趋势.粉料组的总料重比为1.87较颗粒饲料组的1.76高出6.25%,颗粒料较粉料饲喂经济效益为好.     

日粮磷水平对22~42日龄肉仔鸡胴体性能及肌肉品质的影响

为研究日粮磷水平对22~42日龄肉仔鸡胴体性能和肉品质的影响,选用500只1日龄爱拔益加肉鸡公雏,于1~21日龄统一饲喂相同的玉米—豆粕型配合日粮(含非植酸磷实测值为0.39%),于22日龄从中选取360只鸡,按体重相近原则随机分成10个处理组,每个处理组6个重复笼,每个重复笼6只鸡,分别饲喂不添加无机磷的玉米—豆粕型日粮(对照组,含非植酸磷0.09%)及在基础日粮中分别添加0.05%、0.10%、0.15%、0.20%、0.25%、0.30%、0.35%、0.40%和0.45%无机磷(饲料级CaHPO₄),饲养21 d。结果表明,日粮添加适宜水平的无机磷可显著提高42日龄肉仔鸡屠宰率和全净膛率(P<0.1),但日粮磷水平对42日龄肉仔鸡肉品质各指标及其他胴体性能指标均无显著影响(P>0.1)。     

22～42日龄黄羽肉鸡钙需要量研究

本试验旨在研究不同饲粮钙水平对22～42日龄黄羽肉鸡生长性能、胫骨性能和血清生化指标的影响,探讨22～42日龄黄羽肉鸡的钙需要量。试验选用22日龄岭南黄羽肉公鸡1 200只,分为6个处理,每个处理5个重复,每个重复40只鸡。处理1(对照组)肉鸡饲喂玉米-豆粕型基础饲粮(钙水平为0.45%),处理2～6(试验组)肉鸡饲喂在基础饲粮中添加不同水平石粉的试验饲粮,饲粮钙水平分别为0.60%、0.75%、0.90%、1.05%和1.20%,其他营养水平各处理基本一致。试鸡自由采食与饮水。试验期21 d。结果表明:1)在基础饲粮中添加钙显著提高了试鸡42日龄体重和平均日增重(P<0.05),显著降低了料重比(P<0.05),0.75%、0.90%、1.05%和1.20%钙水平组平均日采食量显著低于对照组和0.60%钙水平组(P<0.05)。2)不同饲粮钙水平对试鸡胫骨鲜重无显著影响(P>0.05),而对胫骨折断力、脱脂胫骨干重、胫骨灰分含量、脱脂胫骨灰分含量、脱脂胫骨中钙和磷含量、胫骨灰分中钙和磷含量影响显著(P<0.05),0.90%和1.05%钙水平组胫骨性能指标均显著优于对照组(P<0.05)。3)不同饲粮钙水平对试鸡血清钙、磷含量无显著影响(P>0.05)。综合得出,以生长性能和胫骨性能为评定指标,22～42日龄黄羽肉鸡钙需要量分别为0.60%和0.90%。     

Liver mitochondrial oxygen consumption and proton leak kinetics in broilers supplemented with dietary copper or zinc following coccidiosis challenge

Mitochondrial respiration was assessed in sixteen 7‐day‐old broilers as a subset of a larger study assessing the effects of Cu and Zn supplementation above requirements with a coccidiosis challenge on gain/feed ratio. The birds were selected from four treatments (four birds/treatment): a control diet (Cu 15 mg/kg and Zn 60 mg/kg) + coccidiosis challenge (CC), a Cu diet with 245 mg/kg Cu from tribasic copper chloride (TBCC) + CC, a negative control diet (Cu 15 mg/kg and Zn 60 mg/kg) ‐ CC and a Zn diet with 2000 mg/kg Zn from ZnO. The diets were composed of 49% corn, 40% soybean meal, 6.2% vegetable oil (diet dry matter = 90.62%, crude protein = 21.37%, fat = 7.7%, metabolizable energy = 12.1 MJ/day) and were fed for 14 days. Birds were dissected, and approximately one gram of liver tissue was used for mitochondrial oxygen consumption and proton leak kinetics assays. Respiratory control ratio and mitochondrial proton leak assessed by calculating rates of oxygen consumption at 175mV membrane potential were greater for the negative control group, but there were no differences in average gain/feed among treatments. In summary, broilers that did not undergo coccidiosis challenge had lower proton leak and higher respiratory control ratio. However, the impact of supplementation of Cu and Zn above requirements did not appear to prevent changes in respiratory control ratio and proton leak kinetics with coccidiosis challenge.     

Body Weight,Carcass Yield,and Intestinal Contents of Broilers Having Sodium and Potassium Salts in the Drinking Water Twenty-Four Hours Before Processing

The purpose of this study was to investigate the effects of drinking water supplementation with graded increases of Na and K salts on the performance and gut contents of broilers before processing. Birds had no water, tap water, or water supplemented with sodium bicarbonate or potassium chloride in the concentrations of 0.15, 0.30, and 0.45% in the last 12 and 24 h before processing. The last 12 h coincided with preslaughter feed withdrawal. Cobb × Cobb 500 male broilers (46 d old) were set in a completely randomized experimental design with 8 treatments and 9 replications of 9 birds each. Birds were individually processed within a period of 12 h of feed withdrawal every 2 h. Individual weighing was followed with electrical stunning and removal of intestinal contents of the upper (crop through the gizzard) and lower segment (duodenum through cloaca). Water intake increased linearly with greater salt concentrations in the water (P < 0.05). Body weight loss increased linearly through the feed withdrawal; however, it was greater with birds without water access (P < 0.0001). There were no effects of treatments on the yields of carcass and cuts as well as on the intestinal contents at all evaluated times. Intestinal contents from upper and lower segments were decreased with time, but responses to the water treatments were not observed (P > 0.05). It is concluded that increasing water intake through the use of Na and K salts did not affect the rate of gut emptying before processing.     

肉仔鸡生长性能与饲粮营养水平关系模型的建立及应用

本试验旨在通过研究饲粮代谢能(metabolizable energy,ME)和粗蛋白质(crude protein,CP)水平对内仔鸡生长性能和屠宰指标的影响,建立生长性能与ME、CP的回归关系模型,并运用所建模型选择具有最佳效益的ME、CP水平.采用ME和CP 3×3随机交叉试验设计,将饲粮分为9个处理,3个ME水平分别为13.18、12.55、11.92MJ/kg,3个CP水平分别为21.50％、20.50％、19.50％.选取1日龄爱拔益加(AA)肉仔鸡1 080只,随机分为9组,每组3个重复,每个重复40只鸡,1 ～21日龄分别饲喂对应试验饲粮,22～42日龄饲喂相同的饲粮.结果表明:1)试验饲粮ME、CP水平对1～21日龄体重和耗料量有显著影响(P＜0.05),对42日龄体重也有显著影响(P＜0.05).2)随着饲粮ME水平的提高,21和42日龄肌胃指数显著降低(P＜0.05),42日龄腹脂率显著增加(P＜0.05).3)应用二元曲线逐步回归方法建立了体重、耗料量与饲粮ME、CP水平的回归关系模型.应用举例表明,建立的回归关系模型对确定肉仔鸡饲粮最佳效益的ME、CP水平有很强的实用性.     

Which source and level of dietary sodium is appropriate for broiler chickens reared in a high‐altitude area?

This study investigated effect of increasing level of dietary sodium using sodium bicarbonate or sodium chloride on growth performance, mortality, characteristics of carcass, organs and tibia, calcium and phosphorus of serum in broilers reared in a high‐altitude area (1,700 m above sea level). A total of 588 Ross 308 male broiler chicks were used in seven treatments, six replicates per treatment of 14 birds per each from 1 to 38 d of age. Seven dietary treatments consisted of a basal diet (with 0.16% sodium and 0.23% chloride), top‐dressed for six diets to give three supplementary levels of sodium (0.07%, 0.14% and 0.21%) from sodium bicarbonate (respectively by 0.26%, 0.52% and 0.78%) or sodium chloride (respectively by 0.18%, 0.36% and 0.54%), resulting in seven diets with total sodium and chloride levels of 0.16% and 0.23%, 0.23% and 0.23%, 0.30% and 0.23%, 0.37% and 0.23%, 0.23% and 0.33%, 0.30% and 0.44%, 0.37% and 0.55% respectively. Increasing sodium level improved feed conversion ratio (FCR) linearly and quadratically. However, when FCR was calculated without adjusting for feed intake of mortalities, the enhanced sodium level did not improve this parameter. Increasing sodium level via sodium chloride enhanced ascites mortality, total mortality, relative weight of heart and right ventricle linearly. Increasing sodium level reduced serum calcium and enhanced serum phosphorus linearly; however, there was a linear tendency to increase tibia ash when sodium level was enhanced by sodium bicarbonate (p = 0.08) or sodium chloride (p = 0.07). Increasing sodium level via sodium bicarbonate tended (p = 0.08) to reduce tibia strength linearly. In conclusion, a diet with 0.16% sodium and 0.23% chloride is enough for broiler chicken reared in a high‐altitude area, and increasing dietary sodium level via sodium chloride has detrimental effect on survivability of broiler in such condition.