Growth Performance,Meat Yield,and Economic Responses of Broilers Provided Diets Varying in Amino Acid Density from Thirty-Six to Fifty-Nine Days of Age

Providing broilers diets formulated to a high amino acid density early in life improves subsequent growth performance and meat yield. Diets formulated to high amino acid concentrations beyond 5 wk of age may increase breast meat yield but may not be economically justified. This study examined growth, meat yield, and economic responses of broilers provided diets varying in amino acid density from 36 to 59 d of age. Birds were given a 4-phase feeding program: starter (1 to 17 d), grower (18 to 35 d), withdrawal-1 (WD1; 36 to 47 d), and withdrawal-2 (WD2; 48 to 59 d of age). All birds were fed a common, high amino acid density diet to 35 d of age (HH). Broilers were provided diets characterized as being high (H), moderate (M), or low (L) in amino acid density for the WD1 and WD2 periods. Dietary treatments were HHHH, HHHM, HHHL, HHMM, HHML, and HHLL from d 1 to 59, with H, M, and L representing the diets fed during each of the 4 periods (starter, grower, WD1 and WD2).Cumulative feed conversion was improved when the HHHH feeding regimen was fed, whereas other final live performance measurements were not affected. Decreasing amino acid density (HHLL and HHHL) limited yields of breast fillets, tenders, and total white meat when compared with the HHHH regimen. As amino acid density decreased from HHHH to HHHM, HHMM, and HHML, carcass yield and breast meat yield were not affected. In general, providing the HHHH feeding regimen increased economic gross feeding margin compared with the other dietary treatments.     

Growth Performance,Meat Yield,and Economic Responses of Broilers Fed Diets Varying in Metabolizable Energy from Thirty to Fifty-Nine Days of Age

Two studies examined responses of broilers to diets varying in AME from 30 to 59 d of age. A 59-d termination allows for evaluation of energy needs applicable to “big bird” programs, because research on nutritional needs for such programs is warranted. Two experiments were conducted: experiment (exp.) 1 having low temperatures whereas exp. 2 used moderate temperatures. The treatments in exp. 1 and 2 were AME concentrations ranging from 3,175 to 3,310 kcal/kg with CP, TSAA, and Lys being identical across all treatments. In exp. 2, an additional treatment consisted of a diet containing 3,310 kcal of AME/kg with CP, TSAA, and Lys being increased by 4% of those specifications used in the other treatments so as to minimize differences in energy:CP ratio.In both experiments, feed consumption and conversion decreased linearly as dietary AME increased, but breast meat yield was reduced with the high AME diet and only increasing amino acids in exp. 2 ameliorated the negative effect. Live production costs and gross feeding margin (bird return over feed costs) were optimized in exp. 1 with 3,220 kcal of AME/kg of diet, but 3,310 kcal of AME/kg of diet and increased amino acids were needed in exp. 2 for improved monetary returns. In both experiments, broilers had similar caloric consumption indicating that these broilers can compensate to varying dietary AME concentrations within practical limits. These results demonstrated that the response to dietary AME was more pronounced under moderate ambient temperatures.     

Dietary Apparent Metabolizable Energy and Amino Acid Density Effects on Growth and Carcass Traits of Heavy Broilers

Two experiments (EXP) were conducted to evaluate the interactive effects of dietary AME and amino acid (AA) density (total basis) on broiler chickens from 42 to 56 d of age. In EXP 1, diets were formulated to contain low AME (3,140 kcal/kg) and moderate AME (3,240 kcal/kg) in combination with moderate AA (16.2% CP, 0.88% Lys, and 0.75% TSAA) and high AA (18.0% CP, 0.98% Lys, and 0.83% TSAA) and fed to male broilers. Dietary treatments in EXP 2 were diets formulated to contain moderate AME (3,220 kcal/kg) and high AME (3,310 kcal/kg) combined with moderate and high AA concentrations used in EXP 1 and fed to male and female broilers. In general, dietary AME and AA did not interact to influence growth and meat yield responses. Broilers provided the low AME diet in EXP 1 consumed more feed and had poorer feed conversion but had higher total breast meat yield than birds fed the moderate AME diet. In EXP 2, broilers fed the high AME diet from 42 to 56 d had increased BW gain, decreased feed consumption, and improved feed conversion. Feeding the high AA diets in both EXP decreased feed consumption, improved feed conversion, and increased total breast meat yield. Nutritionists establishing nutritional programs for heavy broilers late in development from 2.5 to 3.6 kg may need to consider increasing AA density to optimize breast meat yield. Increasing the AME content of the diet improves feed conversion but not breast meat yield.     

Dietary Amino Acid Responses of Mixed-Sex Broiler Chickens From Two to Four Kilograms

Two experiments were conducted to assess dietary amino acid density responses on mixed-sex broiler live performance, meat yields, and economics from 36 to 60 d. In experiment 1, broilers were fed a common feeding program to 35 d. Dietary treatments were high (H), moderate (M), and low (L) amino acid density from 36 to 47 d of age and H or L amino acid density from 48 to 60 d of age. Dietary treatments were high-high (HH), high-low (HL), moderate-low (ML), and low-low (LL) during a 60-d production period. In experiment 2, common diets were provided from 1 to 47 d of age. Dietary treatments were H, M, L, and suboptimum (S) amino acid density and fed from 48 to 60 d of age. In experiment 1, increasing dietary amino acid density to HH improved cumulative feed conversion (1 to 60 d) by 4 points over the ML- and LL-fed birds. Broilers provided the HH regimen had 0.6% more total breast meat yield than the LL-fed birds. In experiment 2, broilers fed the H feeding regimen lowered cumulative (1 to 60 d) feed conversion by 3, 5, and 6 points and reduced abdominal fat percentage by 0.28, 0.23, and 0.23%, respectively, compared with the M-, L-, and S-fed birds. Decreasing dietary amino acid density from H to S reduced total breast meat weight and yield by 47 g and 0.82%, respectively. In general, feeding HL (experiment 1) and H (experiment 2) diets increased gross feed margins over the other dietary treatments with diverse diet cost and meat price scenarios.     

The Effects of Photoperiod Length,Light Intensity,and Feed Energy on Growth Responses and Meat Yield of Broilers

A study was conducted to assess the effects of photoperiod length (constant 23L:1D vs. a photoperiod program going from decreasing to increasing quantity of light), light intensity (bright vs. a dim, reducing intensity), and feed ME levels (low vs. high) on performance and carcass characteristics of female broilers grown to 56 d. Use of a treatment with early decreasing photoperiod followed by an increasing photoperiod reduced feed consumption and subsequent BW early. However, growth compensation occurred and feed consumption and BW were similar across photoperiod treatments by study end. Likewise, reducing light intensity (from 1 to 0.25 fc) stimulated feed consumption and a subsequent BW improvement early, as compared with high-intensity (2 fc) lighting maintained at a constant level. However, the disparity in feed consumption and BW, as influenced by light intensity, did not persist throughout the growing period. Feed conversion was not noticeably affected by photoperiod or light intensity treatments. Minimal effects of lighting were observed for carcass or part yields; however, there appeared to be a subtle substitution effect between leg, wing, and breast yield influenced by lighting program. Birds exposed to the decreasing–increasing photoperiod and dim, reducing light treatments yielded more leg and wing at the expense of breast. Feeding a low ME diet resulted in increased feed consumption and feed conversion. However, birds consuming a low ME diet were more uniform. No effects of treatment on mortality were measured. These data indicate that a decreasing–increasing photoperiod can be used effectively to reduce early growth, yet allow birds to compensate as they approach market age. Low intensity lighting, however, appears to stimulate early feed consumption and growth, although this effect is transitory. Furthermore, the increased feed conversion of birds grown on the low energy diet may make its use less desirable.     

蛋氨酸螯合锌替代硫酸锌对肉鸡生产性能、肉品质及抗氧化指标的影响

本试验旨在研究蛋氨酸螯合锌替代硫酸锌对肉鸡生产性能、肉品质及抗氧化指标的影响。试验选用1日龄体重接近的健康爱拔益加（AA）肉公鸡200只,随机分为2个处理,每个处理5个重复,每个重复20只鸡。各处理组肉鸡均饲喂基础日粮且将Zn的添加水平定为40 mg/kg,其中处理1组以硫酸锌形式添加锌,处理2组以蛋氨酸螯合锌形式添加锌。试验期为42 d。结果表明,①与硫酸锌相比,蛋氨酸螯合锌显著降低了22~42 d和1~42 d肉鸡的料重比（P < 0.05）,但对各阶段肉鸡平均日采食量、平均日增重以及21和42 d肉鸡体重均无显著影响（P > 0.05）。②蛋氨酸螯合锌替代硫酸锌对42 d肉鸡宰前体重、屠体重、全净膛重、腿肌重、屠宰率、胸肌率和腿肌率均无显著影响（P > 0.05）,但显著降低了42 d肉鸡全净膛率（P < 0.05）,增加了42 d肉鸡胸肌重、腹脂重和腹脂率（P < 0.05）。③蛋氨酸螯合锌替代硫酸锌对42 d肉鸡胸肌肉色、滴水损失和蒸煮损失均无显著影响（P > 0.05）。④与硫酸锌相比,蛋氨酸螯合锌显著提高了21和42 d肉鸡血清铜锌—超氧化物歧化酶（CuZn-SOD）活力以及42 d肉鸡血清总抗氧化能力（T-AOC）（P < 0.05）,降低了21 d肉鸡血清丙二醛（MDA）含量（P < 0.05）,但对21和42 d肉鸡血清谷胱甘肽过氧化物酶（GSH-Px）活力无显著影响。由此可见,蛋氨酸螯合锌替代硫酸锌具有提高肉鸡生产性能和抗氧化功能的作用。     

饲粮赖氨酸和蛋氨酸水平对冬毛生长期银狐生长性能、营养物质消化率、血清生化指标及毛皮性状的影响

本试验旨在研究饲粮赖氨酸和蛋氨酸水平对冬毛生长期银狐生长性能、营养物质消化率、血清生化指标及毛皮性状的影响。选取70只120日龄、平均体重为(5 973±94)g的健康雄性银狐,随机分成7组,每组10个重复,每个重复1只银狐。采用二因子试验设计,赖氨酸添加水平分别为0、0.50%,蛋氨酸添加水平分别为0、0.25%、0.50%、0.75%,基础饲粮中赖氨酸含量为1.15%,蛋氨酸含量为0.66%。试验期51 d。结果表明:1)饲粮赖氨酸和蛋氨酸水平对冬毛期银狐生长性能无显著影响(P>0.05)。2)饲粮赖氨酸和蛋氨酸交互作用对营养物质采食量、排出量及消化率无显著影响(P>0.05);饲粮赖氨酸水平对营养物质采食量、蛋白质排出量及蛋白质消化率无显著影响(P>0.05),对干物质排出量、干物质消化率、脂肪排出量及脂肪消化率产生显著或极显著影响(P<0.05或P<0.01);饲粮蛋氨酸水平仅对干物质排出量产生显著影响(P<0.05)。3)饲粮赖氨酸和蛋氨酸交互作用对血清总氨基酸含量产生极显著影响(P<0.01),对血清总蛋白、白蛋白、尿素氮含量及丙氨酸氨基转移酶、天门冬氨酸氨基转移酶活性无显著影响(P>0.05);饲粮赖氨酸水平对血清总氨基酸含量产生极显著影响(P<0.01);饲粮赖氨酸水平对血清天门冬氨酸氨基转移酶活性产生极显著影响(P<0.01)。4)饲粮赖氨酸和蛋氨酸交互作用对毛皮性状影响不显著(P>0.05);饲粮赖氨酸或蛋氨酸水平对毛皮性状无显著影响(P>0.05)。从降低饲养成本和减少排放角度考虑,冬毛期银狐在基础饲粮中添加0.50%赖氨酸(实际含量1.65%)和0.25%蛋氨酸(实际含量0.91%)对银狐生产有利。     

Effect of Formic Acid and Plant Extracts on Growth,Nutrient Digestibility,Intestine Mucosa Morphology,and Meat Yield of Broilers

The effect of formic acid and 2 plant extracts on performance traits, apparent ileal digestibility (AID), intestine mucosa morphology, and meat yield of broilers was studied in a 49-d experiment. There were 6 treatments: a negative control diet without additives (control); 10 ppm of avilamycin; 5,000 of formic acid; 10,000 ppm of formic acid; 200 ppm of plant extract based on a blend of oregano, cinnamon, and pepper essential oil; and 5,000 ppm of hydroalcoholic plant extract from sage, thyme, and rosemary leaves. A total of 312 Ross chicks were distributed into 24 groups of 13 in each, comprising 4 replicates per treatment. The performance data revealed significantly better FCR in all the supplemented diets except for the 5,000 ppm of hydroalcoholic plant extract diet. All additives improved AID of nutrients. Both acidifier inclusion levels improved villus height, and the group fed the 10,000 ppm of formic acid diet also had the greatest crypt depth; however, villus surface area was not influenced. Meat yield was not affected. It was concluded that the diets with 5,000 and 10,000 ppm of formic acid, and with 200 ppm of plant extract based on a blend of oregano, cinnamon, and pepper essential oils were similar to avilamycin and were beneficial for improving growth traits and nutrient AID. Furthermore, a positive effect of formic acid on intestine mucosa was observed. This experiment involved a small sample, so the additives that showed beneficial effects should be further studied in commercial farms.     

饲粮蛋氨酸水平对高密度饲养肉鸡生长性能、抗氧化及抗应激能力的影响

【目的】探讨饲粮蛋氨酸对肉鸡高密度饲养下生长性能、抗氧化和应激反应的影响。【方法】选取1日龄爱拔益加(AA)肉鸡396只,1～21日龄统一饲喂,于21日龄末选取体重相近的肉鸡随机分为5个处理,每个处理6个重复。对照组肉鸡饲养密度为14只/m²,蛋氨酸水平为0.40%;4个试验组肉鸡饲养密度为20只/m²,饲粮蛋氨酸水平分别为0.35%、0.40%、0.45%和0.50%。试验期21 d,于42日龄采集血浆、肝脏样品,测定应激和抗氧化能力相关指标。【结果】(1)与正常密度组相比,高密度饲养显著降低了42日龄肉鸡体重(BW)、平均日采食量(ADFI)和平均日增重(ADG)(P<0.05),显著提高了肉鸡死亡率(P<0.05)。在高密度饲养情况下：料重比在蛋氨酸水平为0.35%时最高,随着日粮蛋氨酸水平的上升呈线性下降(P<0.05);与蛋氨酸水平0.35%组相比,0.45%和0.50%蛋氨酸组肉鸡死亡率显著降低(P<0.05)。(2)与正常密度组相比,高密度饲养组的血浆总抗氧化力(T-AOC)显著降低(P<0.05)...     

饲粮营养水平对黄羽肉鸡生长性能、肉品质和性成熟的影响

本试验旨在研究饲粮营养水平对黄羽肉鸡生长性能、肉品质和性成熟的影响。采用单因子完全随机设计,将432只1日龄商品代北京油鸡随机分配到高、中和低3种营养水平组,每组4个重复,每个重复36只鸡,自由采食、饮水。饲粮按中速黄羽肉鸡的饲养标准分为3个阶段(1~5周、6~9周和10~13周),每个阶段在保持蛋白质与能量比值不变的情况下分别设置高、中和低3种营养水平。结果表明,1~5周,低营养水平组肉鸡的平均日采食量和平均日增重极显著低于中、高营养水平组(P0.01);中营养水平组的平均日增重显著高于低营养水平组(P0.05),料重比显著低于低营养水平组(P0.05)。饲粮营养水平对肉品质未表现出显著影响(P0.05)。高营养水平组母鸡鸡冠重和鸡冠长度极显著高于中、低营养水平组(P0.01),鸡冠高度显著高于中、低营养水平组(P0.05),高营养水平组有促进卵巢重的趋势(P=0.08)。饲粮营养水平对公鸡性成熟指标未表现出显著影响(P0.05)。由此可见,对于中速型黄羽肉鸡,中营养水平的饲粮能获得较好的生长性能,高营养水平的饲粮能促进母鸡性成熟。     

母体日粮低能量对后代肉仔鸡生长性能、胴体品质和肉质的影响

本文旨在研究母体日粮低能量对后代肉仔鸡生长性能、胴体品质及肉质的影响.试验选用低脂系肉种鸡120羽,随机分成2组,每组60个重复,每个重复1羽,即单笼饲养.在肉种鸡产蛋期产蛋率达到5%进行试验处理,试验分试验组和对照组,试验组代谢能量为对照组的80%孵化后的肉仔鸡按照母体不同能量处理各挑选健康仔鸡,在相同的试验条件下进行饲养,试验期为56 d.结果表明:1)与对照组相比,母体日粮低能量有降低1日龄肉仔鸡体重的趋势,对全期日增重和料重比影响不显著(P＞0.05);2)与对照组相比,母体日粮低能量对后代肉仔鸡胸肌和腿肌的水分、脂肪和蛋白质含量,胸肌率和腹脂率均无显著影响(P＞0.05),但显著增加腿肌率(P＜0.05);3)与对照组相比,母体日粮低能量对后代肉仔鸡胸肌和腿肌的pH、红度、黄度、滴水损失和蒸煮损失均无显著影响(P＞0.05),但pH、红度和黄度值有升高趋势,滴水损失和蒸煮损失有降低趋势,胸肌和腿肌剪切力显著降低(P＜0.05);4)与对照组相比,母体日粮低能量显著提高后代肉仔鸡胸肌和腿肌肌纤维密度(P＜0.05),显著降低后代肉仔鸡胸肌和腿肌肌纤维直径(P＜0.05).本试验的研究结果表明:母体日粮低能量对后代肉仔鸡的胴体品质及肉质能产生一定的影响.     

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...     

Live Performance and Immune Responses of Straight-Run Broilers: Influences of Zinc Source in Broiler Breeder Hen and Progeny Diets and Ambient Temperature During the Broiler Production Period

Supplemental zinc in broiler diets has been reported to be more available to the chick when provided as a zinc-amino acid complex rather than an inorganic source. Previous work with broiler breeder and turkey hens has indicated that supplementing diets with zinc-amino acid complexes enhances immune status and livability of progeny. This study examined the effects of supplemental dietary zinc source [ZnSO₄ or Availa Zn 100 zinc-amino acid complex (ZnAA)] provided to broiler breeder hens and their progeny on live performance and immune status of broilers. Broiler breeder and progeny diets were supplemented with 160 and 140 ppm zinc, respectively. In addition to the dietary treatments, the broilers were subjected to either optimum or suboptimum temperatures during the first weeks of production. Supplementing broiler breeder hen and progeny diets with ZnAA and ZnAA + ZnSO₄, respectively, improved cumulative feed conversion (FC) of broilers. Providing diets supplemented with ZnSO₄ to hens or exposing broilers to optimum temperatures enhanced humoral immune response of progeny. Subjecting broilers to suboptimum brooding temperatures increased feed intake, but a higher incidence of mortality occurred primarily encompassing the first week of the growout. These data indicate that brooding temperature affected broiler performance, whereas the response to dietary zinc source was less pronounced.     

1～21日龄爱拔益加×罗曼肉杂鸡饲粮代谢能、粗蛋白质、蛋氨酸和赖氨酸适宜水平研究

本试验旨在研究1~21日龄爱拔益加(AA)×罗曼肉杂鸡饲粮代谢能、粗蛋白质、蛋氨酸和赖氨酸的适宜水平。采用L_9(3~4)正交试验设计,饲粮代谢能水平分别为11.70、12.12、12.54 M J/kg;粗蛋白质水平分别为19.00%、20.00%、21.00%;蛋氨酸水平分别为0.45%、0.50%、0.55%;赖氨酸水平分别为1.00%、1.10%、1.20%。选取1日龄AA×罗曼肉杂鸡864只,随机分为9组,每组6个重复,每个重复16只,试验期21 d。通过饲养试验、屠宰试验等方法检测不同营养水平饲粮的饲喂效果。结果表明:1)饲粮粗蛋白质、蛋氨酸和赖氨酸水平对试验鸡平均日增重有显著影响(P0.05),21.00%粗蛋白质水平组显著高于20.00%粗蛋白质水平组(P0.05),0.50%蛋氨酸水平组显著高于0.55%蛋氨酸水平组(P0.05),1.20%赖氨酸水平组显著高于1.10%赖氨酸水平组(P0.05)。2)饲粮代谢能水平对21日龄试验鸡活体总能含量有显著影响(P0.05),12.12 MJ/kg代谢能水平组显著高于12.54 MJ/kg代谢能水平组(P0.05);饲粮蛋氨酸水平对试验鸡活体粗脂肪含量有显著影响(P0.05),0.50%和0.55%蛋氨酸水平组显著高于0.45%蛋氨酸水平组(P0.05)。3)饲粮代谢能和粗蛋白质水平对21日龄试验鸡活体能量沉积率有显著影响(P0.05),11.70和12.12 MJ/kg代谢能水平组显著高于12.54 MJ/kg代谢能水平组(P0.05),21.00%粗蛋白质水平组显著高于20.00%和19.00%粗蛋白质水平组(P0.05);1.10%赖氨酸水平组的试验鸡活体赖氨酸沉积率显著高于1.20%赖氨酸水平组(P0.05)。4)饲粮赖氨酸水平对试验鸡血清葡萄糖、尿酸、尿素氮水平有显著影响(P0.05),1.00%赖氨酸水平组血清葡萄糖水平最高,显著高于1.20%赖氨酸水平组(P0.05),1.10%赖氨酸水平组血清尿酸水平最高,显著高于1.20%赖氨酸水平组(P0.05),1.20%赖氨酸水平组血清尿素氮水平最高,显著高于1.10%赖氨酸水平组(P0.05)。5)由回归分析得出1~21日龄AA×罗曼肉杂鸡饲粮代谢能、粗蛋白质、蛋氨酸和赖氨酸适宜水平的计算公式分别为ME=45.33W~(0.75)+183.84△W,CP=19.77 W~(0.75)+626.47△W,Met=1.44 W~(0.75)+10.31△W,Lys=3.01 W~(0.75)+21.28△W(M E为代谢能,W~(0.75)为代谢体重,△W为平均日增重,CP为粗蛋白质,Met为蛋氨酸,Lys为赖氨酸),根据公式计算得出饲粮代谢能、粗蛋白质、蛋氨酸和赖氨酸的适宜水平分别为11.90 MJ/kg、21.08%、0.51%和1.05%。     

乳酸菌对饲喂黄曲霉毒素B1日粮的肉鸡生长性能、养分消化率和屠宰性能的影响

本试验旨在研究黄曲霉毒素B₁(AFB₁)日粮添加乳酸菌(LAB)对肉鸡的生长性能、养分消化率及屠宰性能的影响。试验选用1日龄AA肉鸡公鸡240只,随机分为4个处理组,每个处理6个重复,每个重复10只鸡。正对照组:无AFB₁日粮;负对照组:1~21d:正对照组日粮＋40μg/kgAFB₁,22~42d:正对照组日粮＋80μg/kgAFB₁;LAB组:负对照组日粮＋1.5×10¹¹CFU/kgLAB;HSCAS组:负对照组日粮＋3g/kgHSCAS。试验期42d。试验结果显示,负对照组日粮显著降低了肉鸡平均日采食量和体增重(P<0.05),显著提高了料重比(P<0.05),添加LAB和HSCAS均明显改善了生产性能,且LAB组的效果优于HSCAS组。1~21d时,与负对照组相比,添加LAB干物质、能量、粗脂肪、钙和磷的表观消化率分别提高9.6%(P<0.05)、9.5%(P<0.05)、10.1%(P<0.05)、15.2%(P<0.05)和18.9%(P<0.05),添加HSCAS能将干物质、能量、粗脂肪和磷的表观消化率提高9.7%(P<0.05)、6.6%(P<0.05)、6.3%(P<0.05)和17.4%(P<0.05),且LAB组能量和钙的表观消化率显著高于HSCAS组(P<0.05)。LAB组的全净膛率和胸肌率也显著高于HSCAS组(P<0.05)。综上所述,在AFB₁污染日粮中添加LAB制剂,对肉鸡的生产性能、养分表观消化率和屠宰性能均具有显著的改善作用,其作用效果显著优于HSCAS脱霉剂。     

饲养密度和饲粮赖氨酸水平对公母分饲肉鸡生长性能、胴体组成和健康状态的影响

本试验旨在研究不同饲养密度和饲粮赖氨酸水平对公母分饲肉鸡生长性能、胴体组成和健康状态的影响.试验采用2×2×3三因子完全随机设计,选用罗斯308商品代肉仔鸡公雏1314只和母雏1530只,随机分成12个处理,每个处理6个重复(栏).试验设高、低2个饲养密度,分别为42(16公/m2或18母/m2)和26 kg/m2(1...     

糖化玉米秸秆对22～42日龄肉鸡生长性能、养分代谢率、屠宰性能及肉品质的影响

本试验旨在探讨糖化玉米秸秆(SCS)对22～42日龄肉鸡生长性能、养分代谢率、屠宰性能及肉品质的影响.选择22日龄健康的雌性爱拔益加(AA)肉鸡200只,随机分为4个组,每组5个重复,每个重复10只鸡.对照组饲喂基础饲粮,试验组分别在基础饲粮中添加4％(Ⅰ组)、8％(Ⅱ组)和12％(Ⅲ组)的SCS.试验期21 d.结果...     

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)。