Marginality and Needs of Dietary Valine for Broilers Fed Certain All-Vegetable Diets

Valine is likely the fourth limiting amino acid in most diets based on corn and soybean meal (C/SBM). However, the exact needs for Val are not well known, and information regarding it is sparse. A series of studies was conducted to validate the limitation of Val in all-vegetable diets fed to broilers, and subsequently to quantify an adequate ratio to Lys in high-yield late-developing broilers (Ross × Ross 708) from 21 to 42 d. A preliminary study was designed to evaluate the supplementation of different amino acids likely to be fourth limiting on a C/SBM-based diet, where Lys, TSAA, and Thr were supplemented but no other critical amino acids were given minimums in the formulation. Results obtained for BW gain, abdominal fat weight, and abdominal fat percentage showed that birds were more responsive (P < 0.05) to l-Val supplementation. A follow-up study using a corn-peanut meal (C/PM)-based diet formulated to be deficient in Val validated (P < 0.05) a Val deficiency based on poor growth performance and resulted in an immediate return to good performance when this amino acid was supplemented. Furthermore, the C/PM diet was compared with a nutritionally similar C/SBM diet, and no difference was observed in the performance of broilers fed these diets, thus validating the ability of the C/PM-based diet to support adequate growth of these broilers. This C/PM-based diet was used to feed gradual concentrations of Val, from levels that would be considered deficient (0.59% digestible) up to adequate (0.84% digestible Val). Results indicate that a ratio of Val to Lys of 78, or a minimum dietary value of 0.74% digestible Val (0.82% total Val), should be adequate for this high-yield broiler grown from 21 to 42 d of age.     

日粮锌水平对4~6周龄肉仔鸡生长性能、胴体性能及肉品质的影响

研究日粮锌水平对4~6周龄肉仔鸡生长性能、胴体性能和肉品质的影响。360只1日龄Arbor Acres(AA)肉公雏,0~3周龄统一饲喂同种日粮(含锌86.25 mg/kg),于22日龄从中选取288只鸡按体重随机分成8个处理,每个处理分6个重复笼饲养,每个重复笼6只鸡。分别饲喂不添加锌的玉米-豆粕型基础日粮(对照组,含锌27.66 mg/kg)和在基础日粮中分别添加20、40、60、80、100、120和140 mg/kg锌(试剂级硫酸锌)日粮。试验期21 d。研究结果表明,日粮锌水平对4~6周龄肉仔鸡生长和胴体性能均无显著影响(P>0.10),但日粮中添加适宜水平的锌可显著降低肉仔鸡胸肌、腿肌的滴水损失和胸肌丙二醛含量,提高胸肌L^*值(P<0.10)。     

Safety of Improved Milbond-TX When Fed to Laying Hens at Higher-Than-Recommended Levels

A corn-soybean meal diet was supplemented with 0, 1, or 2% Improved Milbond-TX (IMTX, a hydrated sodium calcium aluminosilicate) for Hy-Line W-36 laying hens selected for good or poor eggshell quality. Supplementing the diet with IMTX had no detrimental effects on egg weight, eggshell weight, albumen quality, feed consumption, or feed conversion during 5 consecutive 28-d periods. Increase in BW over the 5-mo experimental period was not influenced by the addition of IMTX. Results from this study show that an accidental oversupplementation of a laying hen diet with up to 8 times the recommended level of IMTX of the manufacturer, which may occur due to a feed mill mixing error, should not result in adverse performance of laying hens nor should it affect the concentration of moisture in the excreta.     

肉仔鸡体外消化模拟技术评定不同剂量植酸酶作用效果的研究

对肉仔鸡体外消化模拟技术评定不同剂量植酸酶在玉米-豆粕日粮中作用效果的可行性进行了检验.在体外条件下,分别测定了添加与不添加植酸酶的6种玉米-豆粕日粮磷体外消化率和无机磷释放量.结果表明：磷体外消化率和无机磷释放量随植酸酶添加水平的增加而增加（P＜0.01）,添加不同剂量的植酸酶日粮,磷体外消化率和无机磷释放量与肉仔鸡日增重、采食量、回肠磷消化率、胫骨灰分和磷的沉积以及胫骨灰分中磷的含量等指标均存在强相关（R^2=0.971,0.990,0.962,0.903,0.866,0.986和R^2=0.970,0.987,0.976,0.898,0.859,0.984）.利用肉仔鸡体外消化模拟技术,可以评定和预测玉米-豆粕日粮中添加不同剂量植酸酶对肉仔鸡生产性能和磷利用的影响.     

日粮中不同氟含量对AA肉鸡的影响

本研究对ＡＡ肉鸡在一月龄内饲喂不同氟含量日粮。日粮氟含量分别为２５０,５００,１０００ｍｇ／ｋｇ,比较其临床症状,、增重,主要脏器病理组织学变化,腿骨Ｘ光检查及胫骨氟含量测定。结果显示,高氟日粮使ＡＡ雏鸡生长发育受到不同程度的抑制,尤其对骨骼发育影响严重。日粮中２５０ｍｇ／ｋｇ的氟含量对ＡＡ雏鸡并不安全 。     

日粮硒水平对22~42日龄肉仔鸡生长性能及肉品质的影响

为研究日粮硒水平对22~42日龄肉仔鸡生长性能和肉品质的影响,试验选用380只1日龄Arbor Acres（AA）肉公雏,1~21日龄统一饲喂同种正常添加无机硒的玉米-豆粕型日粮（含硒0.47 mg/kg）,于22日龄从中选取体重接近的336只鸡,随机分成6个处理组,每组7个重复,每个重复8只鸡。分别饲喂不添加硒的玉米-豆粕型基础日粮（对照组,含硒0.015 mg/kg）和在基础日粮中分别添加0.10、0.20、0.30、0.40和0.50 mg/kg硒（以亚硒酸钠形式添加）的试验日粮,试验期21 d。结果表明,日粮中添加不同硒水平对22~42日龄肉仔鸡平均日增重、平均日采食量和料重比均无显著影响（P>0.05）;对42日龄肉仔鸡屠宰率、全净膛率、胸肌率、腿肌率和腹脂率均无显著影响（P>0.05）;日粮中添加不同硒水平对42日龄肉仔鸡腿肌剪切力和胸肌肉色L^*值有显著影响（P<0.05）,其中添加0.50 mg/kg硒处理组肉鸡的腿肌剪切力最低,添加0.20和0.50 mg/kg硒处理组肉鸡的胸肌肉色L^*值最低,但其他肉质性状指标在各组间均无显著差异（P>0.05）。综上所述,玉米-豆粕型基础日粮中添加不同水平硒对22~42日龄肉仔鸡生长性能与42日龄肉仔鸡胴体性状均无显著影响,但日粮中添加0.50 mg/kg硒降低了腿肌剪切力和胸肌L^*值,对肉品质有一定的改善作用。     

饲喂高亚麻籽日粮的蛋鸡生产性能恢复研究

选择167只经4个月高亚麻籽饲喂后的产蛋鸡,以玉米豆饼为基础的日粮饲喂80d,观察其生产性能恢复情况。结果表明：高亚麻籽组的蛋鸡体重始终低于正常,产蛋率和体重几乎不能恢复。     

Effects of Multiple-Enzyme Mixtures on Growth Performance of Broilers Fed Corn-Soybean Meal Diets

Two experiments were conducted under hot and cool seasons to investigate the effects of multiple-enzyme mixtures on the growth performance of broilers fed reduced energy corn-soybean meal diets. Broilers responded to enzyme supplementation with greater magnitude in the hot season (experiment 1) than in the cool season (experiment 2). Adding adequate activity levels of α-amylase, β-glucanase, and xylanase to broiler starter and grower corn-soybean diets with a 3% reduction in dietary ME allowed full restoration of growth performance of broilers comparable to those fed the adequate energy positive control diet regardless of season.     

Evaluation of Heat-Stable Phytases in Pelleted Diets Fed to Broilers from Day Zero to Thirty-Five During the Summer Months

Supplementing phytase to broiler diets has been shown to improve phytate P digestibility in commercial broilers. Broiler rations are typically pelleted to promote improved broiler performance, but high pelleting temperatures can inactivate phytase enzymes. Before the introduction of heat-stable phytase products, phytase enzymes were generally added postpelleting to limit the effect of pelleting temperature on phytase activity. Therefore, the objective of this study was to evaluate postpelleting phytase activity of 3 concentrations of 2 heat-stable phytase enzymes and their efficacy when fed to 0- to 35-d-old broilers. After pelleting the phytase-supplemented diets at 93.3°C, the retained phytase activities of the 2 enzymes were similar, suggesting equivalent heat stability. Supplementing phytase to deficient nonphytate P diets improved FCR by 3% (P ≤ 0.05) compared with the FCR of birds fed an unsupplemented deficient diet. No differences in tibia ash (TA) were detected between the 2 phytase sources; however, TA of birds fed supplemental phytase at the 2 greatest concentrations was improved (P ≤ 0.05) compared with the TA of birds fed nonphytate P-deficient diet. These results suggest that the prepelleting inclusion of heat-stable phytase enzymes may be a viable alternative to postpellet application of phytase for improving P utilization in broilers.     

Effects of a New Recombinant Phytase on the Performance and Mineral Utilization of Broilers Fed Phosphorus-Deficient Diets

An experiment was conducted with Arbor Acres broiler chickens that were fed 3 experimental diets—a control diet containing an adequate level of available phosphorus (AP) and 2 diets that were deficient in AP but supplemented with phytase at a level of either 500 or 750 phytase units/kg—to assess the effects of a novel microbial phytase supplement in broilers fed AP-deficient diets on growth performance and mineral utilization. Similar average daily gain, feed intake, and feed efficiency (P > 0.05) were obtained among broilers fed different diets. Compared with broilers fed the control diet, broilers fed diets with phytase had greater (P < 0.05) retention of Ca, P, and Zn. Moreover, the levels of Cu, Zn, Mg, and Mn in the tibia bone at 28 d of age, and Zn and Mn at 42 d of age in birds fed diets with phytase exceeded (P < 0.05) those of birds fed the control diet. Supplementation of phytase increased Zn and Mg contents in the plasma at 42 d of age. Birds responded similarly to phytase supplemented at a level of 500 or 750 phytase units/kg in terms of growth performance, mineral retention, and mineral content in the serum and bone. Therefore, with the supplementation of this novel phytase, it is possible to reduce the dietary levels of P and other minerals to below the recommended levels of the Feeding Standard of Chicken in P. R. China (ZB B 43005-86).     

日粮中添加外源核苷酸以AA肉鸡生产性能的影响

试验旨在探究日粮中添加外源核苷酸对从肉鸡生产性能的影响.100只1日龄AA肉鸡随机分成4组:对照组,低、中、高剂量外源核苷酸试验组,每组25R.对照组饲喂基础日粮;试验组于22日龄开始,在基础日粮中分别添加0.05%、0.10%和0.20%外源核苷酸,试验期42d.采集血清分析生化指标,结果表明,与对照组相比,添加外源核苷酸显著提高了AA肉鸡增重和饲料利用率,显著提高胸肌和腿肌重量,同时显著降低腹脂率.添加外源核苷酸对血清中的总胆固醇和甘油三酯含量无显著影响,但可显著降低非酯化脂肪酸含量.结果提示,日粮中添加外源核苷酸能在提高AA肉鸡增重和肌肉重量的同时降低脂肪的沉积,从而提高生产性能.     

Safety of Improved Milbond-TX When Fed in Broiler Diets Limiting in Available Phosphorus or Containing Variable Levels of Metabolizable Energy

Improved Milbond-TX (IMTX), a hydrated sodium calcium aluminosilicate, was added to broiler diets at 0, 1, or 2% in 2 experiments. In experiment 1, three concentrations of available P, 0.22, 0.32, and 0.42%, were combined with the IMTX in isocaloric and isonitrogenous corn-soybean meal-based diets and fed to male broilers for 21 d. In experiment 2, the IMTX was added to isonitrogenous broiler diets calculated to contain 2,940, 3,020, or 3,100 kcal of ME/kg and also fed for 21 d. Deficient dietary P reduced feed intake and BW at 7, 14, and 21 d of age, but IMTX had no effect even when fed at 8 times the amount recommended by the manufacturer (0.25%) to ameliorate the toxic effects of feed mycotoxins. Similarly, increasing the energy level of the diet resulted in improved BW and feed conversion, but IMTX fed at 8 times the amount recommended by the manufacturer had no detrimental effect on chick performance. There was no interaction found between IMTX and energy or available P for any performance measure. Addition of IMTX to the diet above the recommended concentration of the manufacturer also had no detrimental effect on percentage of toe ash or excreta moisture.     

Determination of Ileum Microbial Diversity of Broilers Fed Triticale- or Corn-Based Diets and Colonized by Salmonella

Diversity of the bacterial communities in the ileum of broilers was characterized using denaturing gradient gel electrophoresis. Denaturing gradient gel electrophoresis separation of polymerase chain reaction amplicons of the V2–V3 variable regions of the 16S rDNA is a common method to profile community diversity and has been used to assess the effects of diet and antibiotics on the ileal bacterial community of chickens. Broilers raised either on litter floor or in cage batteries were fed either a finely ground corn- (control), a finely ground triticale-, or a whole triticale-based diet from 0 to 42 d. Microbial DNA was extracted from the ileum content of 42-d-old broilers, and the 16S rDNA gene was amplified by polymerase chain reaction and the amplicons separated by denaturing gradient gel electrophoresis. Diversity indexes including richness, evenness, diversity, and pairwise similarity coefficients were calculated. Diversity indexes were related to the dietary treatments, housing designs, and to changes in Salmonella colonization of broiler ceca as characterized by the most probable number method. Higher microbial diversity indexes were observed among birds fed whole triticale-based diets and reared on litter floors. In contrast, finely ground grain treatments had lower diversity and higher Salmonella prevalence than the whole triticale treatment. The data indicated that combination of high dietary fiber content and increased coarseness of the diet by feeding whole triticale stimulated microbial community diversity and discouraged Salmonella colonization, perhaps through a competitive exclusion-type mechanism.     

不同能量蛋白水平日粮中添加磷脂和NSP酶制剂对肉仔鸡相关生理机能的影响

为了研究磷脂和NSP酶制剂对肉仔鸡消化力的影响,在不同能量蛋白日粮中分别添加磷脂、NSP酶制剂以及二者复合添加。结果表明：磷脂有提高21 d肉仔鸡的肝脏和胰腺器官指数的趋势;3个处理组的养分表观消化率总体上都表现一定降低的趋势;各组空肠消化酶活性多表现一定升高;复合添组提高了21 d空肠黏膜二糖酶活性。