0～35日龄肉用仔鹅日粮适宜粗纤维和粗蛋白水平的研究

采用3×3因子的析因设计,将189只1日龄健康的肉用仔鹅随机分成9组,每组设3个重复,每个重复7只鹅;将日粮的粗纤维和粗蛋白设低、中、高三个水平,配制9种日粮,构成9个处理,研究不同粗纤维和粗蛋白水平对0～35日龄肉鹅生长性能和营养物质利用率的影响。结果表明:0～35日龄肉鹅对日粮中粗纤维水平非常敏感,但对蛋白质水平要求不高。低纤维水平日粮组日增重、料重比明显好于中、高纤维组(P<0.01);日粮粗纤维和粗蛋白质水平极显著影响鹅对能量和蛋白质的利用率(P<0.01)。试验认为0～35日龄肉鹅饲粮粗纤维以3.5%,粗蛋白水平以17%～19%为宜。     

蚕沙对14～70日龄仔鹅生长性能、体尺性状、屠宰性能和脏器指数的影响

本试验旨在研究饲粮中添加不同水平蚕沙对14~70日龄仔鹅生长性能、体尺性状、屠宰性能和脏器指数的影响,以确定仔鹅饲粮中蚕沙的适宜添加水平。选取330只11日龄健康、体重相近的扬州鹅公鹅,随机分为5个组,每组6个重复,每个重复11只鹅。对照组饲喂基础饲粮,试验组分别饲喂添加3%、6%、9%、12%蚕沙的试验饲粮。试验期56 d。结果表明:1)与其他试验组相比,饲粮中添加9%和12%蚕沙显著降低了28、35、42、49、56、63和70日龄仔鹅体重(P<0.05),显著降低14~28日龄、29~70日龄和14~70日龄仔鹅平均日增重(P<0.05),显著提高了料重比(P<0.05)。2)与对照组相比,饲粮中添加9%和12%蚕沙显著降低了胫围、胸宽、胸深、体斜长和半潜水长(P<0.05)。3)饲粮添加蚕沙仅对仔鹅胸肌率有显著影响(P<0.05)。4)饲粮添加蚕沙显著影响了仔鹅十二指肠指数、空肠指数、回肠指数、盲肠指数和直肠指数(P<0.05)。由此可知,饲粮添加3%~6%蚕沙对仔鹅生长性能、体尺性状、屠宰性能、脏器指数没有不良影响,且对肠道的生长发育有一定的促进作用。在生产实践中仔鹅饲粮中蚕沙的添加水平不宜超过6%。     

饲粮中果胶对28～70日龄扬州鹅生长性能、体尺性状、屠宰性能及脏器指数的影响北大核心CSCD

本试验旨在研究饲粮中果胶对28~70日龄扬州鹅生长性能、体尺性状、屠宰性能及脏器指数的影响。选用180只体重相近、健康的28日龄扬州鹅公鹅,随机分为3个组,每组6个重复,每个重复10只鹅。试验Ⅰ组(对照组)饲喂基础饲粮,试验Ⅱ、Ⅲ组分别饲喂添加1.5%和3.0%果胶的试验饲粮。试验期为42 d。结果表明:1)与对照组相比,饲粮中添加1.5%和3.0%果胶显著降低了42、56、70日龄扬州鹅体重(P<0.05),显著降低28~70日龄仔鹅的平均日增重(P<0.05),显著提高了28~70日龄仔鹅的料重比(P<0.05)。2)与对照组相比,饲粮中添加3.0%果胶显著降低了70日龄仔鹅的胸深和胸宽(P<0.05)。3)与对照组相比,饲粮中添加1.5%果胶显著降低了70日龄仔鹅的胸肌率(P<0.05),饲粮中添加3.0%果胶显著降低了70日龄仔鹅的胸肌率和腹脂率(P<0.05)。4)与对照组相比,饲粮中添加3.0%果胶显著提高了70日龄仔鹅的脾脏指数和腺胃指数(P<0.05),显著降低了70日龄仔鹅的法氏囊指数和胸腺指数(P<0.05)。由此可知,饲粮中果胶对28~70日龄扬州鹅的生长性能、体尺性状、屠宰性能及脏器指数具有不良影响,这提示在生产实践中,对于一些富含果胶的饲料原料,应当注意其使用量。     

木薯渣对22～49日龄仔鹅生长性能、屠宰性能及内脏器官发育的影响

本试验旨在研究饲粮中添加不同水平木薯渣对22~49日龄仔鹅生长性能、屠宰性能及内脏器官发育的影响。选取300只19日龄健康、体重相近的扬州鹅公鹅,随机分为5组,每组6个重复,每个重复10只。对照组饲喂基础饲粮,试验组分别饲喂添加5%、10%、15%和20%木薯渣的试验饲粮,试验期28 d。结果表明:1)与对照组相比,饲粮中添加木薯渣显著提高22~28日龄、29~35日龄、22~49日龄仔鹅的平均日采食量和22~28日龄、22~49日龄仔鹅的平均日增重(P0.05),其中22~49日龄仔鹅的平均日增重与木薯渣添加水平呈二次曲线关系(P=0.017),达到最高平均日增重的木薯渣添加水平是12.4%。2)与对照组相比,饲粮中添加木薯渣显著降低仔鹅的肌胃指数和十二指肠的相对重量(P0.05)。3)对各组饲粮增重成本降低的百分比进行曲线模拟,结果呈现二次曲线关系(P0.05);当饲粮中木薯渣添加水平为17.9%时,增重成本降低百分比值最大。由此可见,饲粮中添加木薯渣可以促进22~49日龄仔鹅生长,降低饲料成本,对肌胃、十二指肠的发育有一定的影响。根据饲粮中添加木薯渣对平均日增重最高限量和饲料增重成本的最低限量,建议添加水平为12.4%~17.9%。     

木薯渣在50～70日龄仔鹅饲粮中的适宜添加量

本试验旨在研究木薯渣在50~70日龄仔鹅饲粮中的适宜添加量。选取200只50日龄健康、体重相近的扬州鹅公鹅,随机分为5组,每组4个重复,每个重复10只。对照组饲喂基础饲粮,试验组分别饲喂添加5%、10%、15%和20%木薯渣的试验饲粮,试验期21 d。结果表明:1)与对照组相比,饲粮中添加木薯渣显著降低了10周龄鹅饲粮能量的表观代谢率(P0.05);饲粮中添加10%、15%、20%木薯渣显著提高了64~70日龄和50~70日龄仔鹅平均日采食量(P0.05);饲粮中添加15%、20%木薯渣显著提高了50~56日龄仔鹅的平均日增重(P0.05);饲粮中添加20%木薯渣显著降低了仔鹅的腹脂率(P0.05),显著提高了肌肉中粗灰分的含量(P0.05)。2)饲粮中添加木薯渣对仔鹅其他屠宰性能、饲粮养分表观代谢率及肉品质、肌肉常规养分含量无显著影响(P0.05)。3)由饲料成本降低百分比和经济效益呈现的二次关系可知,当木薯渣添加量为21.4%时,饲料成本降低百分比值最大;当木薯渣添加量为20.9%时,经济效益最高。由此可见,饲粮中添加木薯渣可以促进仔鹅生长,对屠宰性能、饲粮养分表观代谢率、肉品质及肌肉常规养分含量无显著影响。综合仔鹅生长性能、屠宰性能、饲粮表观养分利用率及对经济效益的分析,50~70日龄仔鹅饲粮中木薯渣的适宜添加量为20%。     

饲粮粗纤维缺乏对57～84日龄扬州鹅生长性能、脏器指数和血清生化指标的影响

试验旨在研究饲粮粗纤维缺乏对57~84日龄扬州鹅生长性能、脏器指数和血清生化指标的影响,以研究粗纤维对鹅不可或缺的作用。选取20只56日龄体格健壮的扬州鹅公鹅,按照组间体重差异不显著(P0.05)的原则分为试验组和对照组,每组10只。试验组饲喂粗纤维水平为0%的纯合日粮,对照组饲喂粗纤维水平为6%的基础饲粮,试验期28 d。结果表明:(1)饲粮粗纤维缺乏显著降低了84日龄扬州鹅体重(P0.05),显著降低了57~84日龄扬州鹅的平均日增重(P0.05),显著提高了57~84日龄扬州鹅的料重比(P0.05);(2)饲粮粗纤维缺乏显著降低了57~84日龄扬州鹅血清淀粉酶活性(P0.05),而对其他血清生化指标没有显著影响(P0.05);(3)饲粮粗纤维缺乏显著降低了84日龄扬州鹅的肌胃指数(P0.05),而对心脏指数、肝脏指数、脾脏指数、胸腺指数、法氏囊指数和腺胃指数均没有显著影响(P0.05);(4)饲粮粗纤维缺乏会导致57~84日龄扬州鹅持续排稀便。综上所述,饲粮粗纤维缺乏通过抑制肌胃生长,降低血清淀粉酶活性,导致鹅的生长性能降低,鹅饲粮中需要添加适量水平的粗纤维才能保证正常的生长发育。     

肉仔鹅日粮能量蛋白和纤维水平的探讨

通过对９０只溆浦鹅与本地鹅的杂交后代进行了不同能量，蛋白和纤维水平间的饲养试验，得出以下结论：仔鹅在０～２８日龄期间，日粮粗纤维含量从５％增加到７％，粗蛋白从２４％降到２０％，代谢能从１１．７６ＭＪ／ｋｇ降到１１．３７ＭＪ／ｋｇ，对增重无影响，但代谢能降到１０．９３ＭＪ／ｋｇ时，仔鹅增重速度则极显著缓慢，在２９～５６日龄期间，日粮纤维含量从７％增加到９％，粗蛋白从２０％降到１８％，代谢能从１２．２     

饲粮粗纤维水平对1～28日龄仔鹅盲肠微生物区系的影响北大核心CSCD

本试验旨在研究饲粮粗纤维水平对1~28日龄仔鹅盲肠微生物区系的影响。选取健康、体重接近的1日龄扬州鹅公鹅468只,随机分为3组,每组6个重复,每个重复26只。对照组(Ⅰ组)饲喂基础饲粮,试验组在基础饲粮基础上分别添加1.86%(Ⅱ组)和3.72%(Ⅲ组)微晶纤维素,使Ⅰ、Ⅱ、Ⅲ组饲粮粗纤维水平分别达2.5%、4.3%和6.1%。试验期28 d。结果表明:1)与Ⅱ、Ⅲ组相比,Ⅰ组22~28日龄的平均日增重显著降低(P<0.05),而料重比显著升高(P<0.05)。2)PCR扩增片段变性梯度凝胶电泳(PCR-DGGE)指纹图谱分析结果显示,28日龄时,Ⅱ和Ⅲ组的仔鹅盲肠中的微生物条带数分别比Ⅰ组多18.2%和31.8%。3)Illumina MiSeq高通量测序结果显示,与Ⅱ、Ⅲ组相比,Ⅰ组盲肠微生物操作分类单元(OTU)总数、ACE指数、Chao1指数和Shannon指数下降,Simpson指数增加;拟杆菌门、厚壁菌门的相对丰度降低,变形菌门的相对丰度增加,拟杆菌属、巨单胞菌属、普雷沃菌属的相对丰度降低。4)实时荧光定量PCR结果显示,与Ⅱ、Ⅲ组相比,Ⅰ组盲肠微生物大肠杆菌相对丰度增加(P<0.05),梭菌Ⅳ、梭菌ⅩⅣ、乳酸菌、韦荣球菌、拟杆菌和双歧杆菌的相对丰度显著降低(P<0.05)。由此可见,通过添加纤维素提高饲粮粗纤维水平到4.3%和6.1%,可增加1~28日龄仔鹅盲肠微生物多样性和潜在有益菌的相对丰度,降低潜在有害菌的相对丰度,改善盲肠微生物平衡。     

铁对5～16周龄五龙鹅生长性能、屠宰性能、肉品质和营养物质利用率的影响

本试验旨在研究铁对5~16周龄五龙鹅生长性能、屠宰性能、肉品质和营养物质利用率的影响,以确定铁的适宜添加水平。试验选用5周龄五龙鹅360只,随机分为6个组,每个组6个重复,每个重复10只。Ⅰ组为对照组,饲喂基础饲粮,Ⅱ~Ⅵ组分别饲喂在基础饲粮中添加20、40、60、80、100 mg/kg铁的试验饲粮。试验期12周。结果表明:1)饲粮中添加适宜水平铁有助于五龙鹅的生长,添加40~60 mg/kg的铁能极显著提高5~16周龄鹅体重和平均日增重(P0.01),极显著降低料重比(P0.01);通过二次曲线拟合,当饲粮铁添加水平为62.5 mg/kg时平均日增重最大;铁添加水平过高,生长性能下降。2)饲粮中铁添加水平为40~60 mg/kg时,屠宰率、半净膛率显著高于对照组(P0.05);饲粮铁添加水平对腹脂率、胸肌率、腿肌率没有显著影响(P0.05)。3)饲粮铁添加水平对鹅肉色度无显著影响(P0.05),对鹅肉的剪切力、系水力、失水率和p H有增加趋势(P0.05)。4)饲粮中添加适宜水平铁能减少粪便中的氮,提高沉积氮,从而增加蛋白质的转化效率,并显著或极显著增加粗脂肪、粗纤维、中性洗涤纤维、酸性洗涤纤维的营养物质利用率(P0.05或P0.01)。由此可见,饲粮中添加适宜水平的铁对鹅生长性能、屠宰性能、肉品质和营养物质利用率有显著影响,建议5~16周龄五龙鹅饲粮中铁的适宜添加水平为52.7~62.5 mg/kg。     

高纤维饲粮中添加果胶酶和纤维素酶对五龙鹅生长性能、屠宰性能及肉品质的影响

本试验旨在研究高纤维饲粮中添加果胶酶和纤维素酶对五龙鹅生长性能、屠宰性能及肉品质的影响。选用1日龄五龙鹅216只,随机分为6组,每组3个重复,每个重复12只鹅。Ⅰ组为对照组,饲喂高纤维基础饲粮,Ⅱ、Ⅲ、Ⅳ组分别在基础饲粮中添加5 000、10 000、15 000 U/kg的果胶酶,Ⅴ组在基础饲粮中添加5 000 U/kg果胶酶和40 000 U/kg纤维素酶,Ⅵ组在饲粮中添加10 000 U/kg果胶酶和40 000 U/kg纤维素酶。试验分1~4周龄和5~16周龄2个阶段,试验期16周。结果表明:1)与对照组相比,Ⅲ组显著提高了1~4周龄鹅平均日采食量(P<0.05),极显著降低了5~16周龄鹅料重比(P<0.01);Ⅵ组极显著提高了1~4周龄和5~16周龄鹅平均日增重(P<0.01),极显著降低了1~4周龄和5~16周龄鹅平均日采食量和料重比(P<0.01)。2)与对照组相比,Ⅲ组极显著提高了4周龄鹅的半净膛率、全净膛率(P<0.01),Ⅴ、Ⅵ组极显著提高了4周龄鹅的屠宰率、半净膛率、全净膛率和腿肌率(P<0.01),Ⅵ组极显著提高了16周龄鹅的屠宰率、半净膛率、胸肌率和腿肌率(P<0.01)。3)与对照组相比,Ⅲ组显著降低了鹅肉的失水率(P<0.05),Ⅵ组显著提高了肉色亮度(P<0.05),Ⅴ、Ⅵ组极显著降低了鹅肉的失水率(P<0.01)。由此可见,高纤维饲粮中添加10 000 U/kg果胶酶能够提高五龙鹅的生长性能和屠宰性能,10 000 U/kg果胶酶与40 000 U/kg纤维素酶配合使用效果更佳。     

1～3周龄黑羽公番鸭代谢能和粗蛋白质需要量的研究

本试验旨在确定1～3周龄黑羽公番鸭代谢能和粗蛋白质的需要量.采用3×3双因子试验设计,设3个代谢能水平( 11.72、12.14、12.55 MJ/kg)和3个粗蛋白质水平(17％、19％、21％),配制9种试验饲粮.选取1日龄黑羽公番鸭378羽,随机分为9个处理,每处理设6个重复,每重复7只鸭,每组试鸭随机饲喂1种试...     

饲粮纤维来源对合浦鹅生产性能、血清生化指标和养分代谢的影响

选取体重相近、健壮的4周龄合浦鹅60羽,随机分为稻草粉组、玉米秸秆粉组和花生藤粉组,每组20羽,饲养42 d。于8周龄时从上述试验组中各选取5羽体重接近的鹅,测定其对3种纤维来源的饲粮养分的利用率。结果表明,(1)饲喂含粗蛋白质约为13.80%,粗纤维约为8.0%的饲粮,稻草粉、玉米秸秆、花生藤用作饲粮纤维来源,不影响合浦鹅的日增重、血清生化指标和屠宰性能(P>0.05)。(2)花生藤粉组饲粮的中性洗涤纤维、半纤维素和无氮浸出物的表观代谢率极显著高于其他2组(P<0.01);稻草粉组和花生藤粉组的饲粮粗蛋白质、能量的代谢率显著高于玉米秸秆粉组(P<0.05)。     

玉米干酒糟及其可溶物对仔鹅生长性能及肉品质的影响

本试验旨在研究饲粮中添加不同水平玉米干酒糟及其可溶物（ＤＤＧＳ）对仔鹅生长性能和肉品质的影响。选取 １６０只 ３周龄扬州鹅（母）,随机分为 ４个组,每个组 ４个重复,每个重复１０只鹅。对照组饲喂玉米 －豆粕型基础饲粮,试验Ⅰ、Ⅱ、Ⅲ组玉米 ＤＤＧＳ占饲粮的比例分别为 １０％、２０％、３０％。在试验期每周末称量禁食 １２ｈ后的仔鹅体重,以重复为单位记录周采食量,在仔鹅 １０周龄末屠宰采样,分离胸肌和腿肌,测定仔鹅肉品质。预试期 １周,正试期 ６周（４～１０周龄）。结果表明：饲粮中添加玉米 ＤＤＧＳ对试验组的平均日采食量、料重比无显著影响（Ｐ＞０．０５）;５周龄时,试验Ⅰ组的体重显著高于试验Ⅲ组（Ｐ＜０．０５）,８、９周龄时,试验Ⅱ组的体重显著高于对照组（Ｐ＜０．０５）,但在整个试验期间各组的平均日增重无显著差异（Ｐ＞０．０５）。试验组胸肌的 ｐＨ、肉色、剪切力、失水率与对照组无显著差异（Ｐ＞０．０５）。在脂质过氧化水平测试期第 １天,试验Ⅰ和Ⅱ组硫代巴比妥酸反应物含量显著高于对照组（Ｐ＜０．０５）,在第４、５天,３个试验组均显著高于对照组（Ｐ＜０．０５）,从整个测试期的每天测试结果看,各组间的硫代巴比妥酸反应物含量均有随着玉米 ＤＤＧＳ添加水平的增加呈先上升后下降的趋势。综上所述,在仔鹅的饲粮中添加至 ３０％的玉米 ＤＤＧＳ对仔鹅的生长和常规的肉品质指标无不利影响,但会提高仔鹅肌肉的脂质氧化水平,容易引起酸败。     

The effects of pharmacological levels of zinc,diet acidification,and dietary crude protein on growth performance in nursery pigs

This experiment was conducted to evaluate potential replacements for pharmacological levels of Zn (provided by Zn oxide), such as diet acidification (sodium diformate) and low dietary crude protein (CP: 21 vs 18%) on nursery pig performance and fecal dry matter (DM). A total of 360 weaned pigs (Line 200 × 400, DNA, Columbus, NE; initially 5.90 ± 0.014 kg) were used in a 42-d growth study. Pigs were weaned at approximately 21 d of age and randomly assigned to pens (five pigs per pen). Pens were then allotted to one of eight dietary treatments with nine pens per treatment. Experimental diets were fed in two phases: phase 1 from weaning to day 7 and phase 2 from days 7 to 21, with all pigs fed the same common diet from days 21 to 42. The eight treatment diets were arranged as a 2 × 2 × 2 factorial with main effects of Zn (110 mg/kg from days 0 to 21 or 3,000 mg/kg from days 0 to 7, and 2,000 mg/kg from days 7 to 21), diet acidification, (without or with 1.2% sodium diformate), and dietary CP (21% or 18%, 1.40% and 1.35% in phases 1 and 2 vs. 1.20% standardized ileal digestible Lys, respectively). Fecal samples were collected weekly from the same three pigs per pen to determine DM content. No 2- or 3-way interactions (P > 0.05) were observed throughout the 42-d study for growth performance; however, there was a Zn × acidifier × CP interaction (P < 0.05) for fecal DM on day 7 and for the overall average of the six collection periods. Reducing CP without acidification or pharmacological levels of Zn increased fecal DM, but CP had little effect when ZnO was present in the diet. From days 0 to 21, significant (P < 0.05) main effects were observed where average daily gain (ADG) and gain:feed (G:F) increased for pigs fed pharmacological levels of Zn, sodium diformate, or 21% CP (P < 0.065). In the subsequent period (days 21 to 42) after the experimental diets were fed, there was no evidence of difference in growth performance among treatments. Overall (days 0 to 42), main effect tendencies were observed (P < 0.066) for pigs fed added Zn or sodium diformate from days 0 to 21, whereas pigs fed 21% CP had greater G:F than those fed 18% CP. Pig weight on day 42 was increased by adding Zn (P < 0.05) or acidifier (P < 0.06) but not CP. In summary, none of the feed additives had a major influence on fecal DM, but dietary addition of pharmacological levels of Zn or sodium diformate independently improved nursery pig performance.     

Effect of dietary crude protein level on growth performance,blood characteristics,and indicators of intestinal health in weanling pigs

An experiment was conducted to test the hypothesis that reducing crude protein (CP) in starter diets for pigs reduces post-weaning diarrhea and improves intestinal health. In total, 180 weanling pigs were allotted to 3 diets containing 22, 19, or 16% CP. Fecal scores were visually assessed every other day. Blood samples were collected from 1 pig per pen on days 1, 6, 13, 20, and 27, and 1 pig per pen was euthanized on day 12. Results indicated that reducing dietary CP reduced (P < 0.01) overall average daily gain, gain to feed ratio, final body weight, and fecal scores of pigs. Pigs fed the 16% CP diet had reduced (P < 0.01) serum albumin compared with pigs fed other diets. Blood urea nitrogen, haptoglobin, interleukin-1β, and interleukin-6 concentrations in serum were greatest (P < 0.01) on day 13, whereas tumor necrosis factor-α and interleukin-10 concentrations were greatest (P < 0.01) on day 6. Villus height in the jejunum increased (P < 0.05) and crypt depth in the ileum was reduced (P < 0.01) if the 19% CP diet was fed to pigs compared with the 22% CP diet. A reduction (P < 0.05) in mRNA abundance of interferon-γ, chemokine ligand 10, occludin, trefoil factor-2, trefoil factor-3, and mucin 2 was observed when pigs were fed diets with 16% CP. In conclusion, reducing CP in diets for weanling pigs reduces fecal score and expression of genes associated with inflammation.     

Effects of two dietary crude protein levels on finishing performance,meat quality,and gene expression of market lambs

Seventeen crossbred lambs were assigned randomly to low-protein (LP; 8% crude protein [CP]; n = 9) and high-protein (HP; 13% CP; n = 8) diets for 9 weeks. The final body weight, average daily feed intake (ADFI), and average daily gain (ADG) of the HP lambs were significantly higher (P < 0.05) than the LP lambs; however, gain to feed ratio (G:F) for the LP lambs was significantly higher (P < 0.05) than the HP lambs. Hot carcass weight (HCW), adjusted fat thickness, and drip loss of longissimus dorsi (LD) muscle were significantly higher (P < 0.05) for the HP than LP lambs. In contrast, instrumental color values L*, a*, b*, C*, and hue angle (H) of meat from the LP lambs scored significantly higher (P < 0.05) than the HP lambs. The LD muscle from HP lambs had significantly greater CLA of cis-9 trans-11 isomer (P < 0.05) than the LP lambs. The gene expression of metabolism and meat quality-related genes of LP was significantly higher than HP (P < 0.05). These results suggest that a higher dietary CP level promotes growth performance for finishing lambs, whereas lower dietary CP level is beneficial for meat quality, especially when evaluating color characteristics in the final product.     

Evaluation of standardized ileal digestible lysine requirement for 8–20 kg pigs fed low crude protein diets

Two experiments were conducted to determine the standardized ileal digestible lysine (SID Lys) requirement for weaned pigs fed with low crude protein (CP) diet. In Experiment 1, 144 pigs were fed a normal CP (20%) diet with 12.3 g/kg SID Lys and five low CP (18.5%) diets providing SID Lys levels of 9.8, 11.1, 12.3, 13.5, and 14.8 g/kg, respectively, for 28 days. Reducing dietary CP from 20% to 18.5% enhanced (p < 0.05) the growth performance. The average daily gain (ADG) and gain to feed ratio (G:F) increased (linear and quadratic; p < 0.05), serum urea nitrogen (SUN) decreased (linear and quadratic; p < 0.05) as SID Lys increased. The SID Lys levels required to maximize ADG and optimize G:F were 12.8 and 13.1 g/kg using a curvilinear plateau model, and to minimize SUN was 13.4 g/kg using a two‐slope broken‐line model, which averaged 13.1 g/kg SID Lys. In Experiment 2, 18 pigs were used in a 12‐day N balance trial and received the same diets of Experiment 1. Total N excretion was decreased when dietary CP reduced and further decreased when SID Lys increased. Collectively, 1.5% dietary CP reduction improved the growth performance and decreased the N excretion; the optimal SID Lys requirement was at 13.1 g/kg of 8–20 kg pigs fed with 18.5% CP diet.     

Effects of feeding diets containing low crude protein and coarse wheat bran as alternatives to zinc oxide in nursery pig diets

Two experiments were conducted to determine the effects of crude protein (CP) level in diets containing coarse wheat bran (CWB) with or without pharmacological levels of Zn (provided by zinc oxide: ZnO) on growth performance and fecal DM of nursery pigs. In experiment 1, 360 barrows (Line 200 × 400, DNA, Columbus, NE, initially 5.6 kg) were allotted to 1 of 6 dietary treatments from d 0 to 21 after weaning with 5 pigs per pen and 12 pens per treatment. Treatments included a positive control diet (21% CP) with 3,000 mg/kg Zn in phase 1 and 2,000 mg/kg in phase 2; negative control (21% CP) with 110 mg/kg added Zn, and 4 diets containing 4% CWB and 110 mg/kg added Zn formulated to contain 21%, 19.5%, 18%, or 16.5% CP. The 2 control diets and 21% CP CWB diet contained 1.40% standardized ileal digestible (SID) Lys in phase 1 and 1.35% SID Lys in phase 2, while the 19.5%, 18%, and 16.5% CP diets contained 1.33, 1.25 and 1.20% Lys, respectively, in both phases. Pigs fed the positive control diet containing pharmacological ZnO had increased (P < 0.05) ADG and G:F compared with the negative control and the 21% CP CWB diet. Reducing CP (concurrently with SID Lys) in diets containing CWB decreased ADG and G:F (linear, P = 0.002); however, fecal DM increased (linear, P = 0.005). In experiment 2, two groups of 300 and 350 pigs, initially 7.0 and 6.2 kg, respectively, were used with 5 pigs per pen and 26 pens per treatment. The objective was to determine if adding back essential AA would improve growth performance of pigs fed the low CP diets. All dietary treatments were fed for 13 days, contained 4% CWB, and consisted of: (1) positive control with 2,000 mg/kg of Zn and 21% CP (1.35% SID Lys); (2) no ZnO and 21% CP; and 3 diets with no ZnO formulated to 18% CP and (3) 1.2% SID Lys; (4) 1.35% SID Lys by the addition of feed grade amino acids (AA), and (5) diet 4 with non-essential amino acids (NEAA; Gly and Glu). Pigs fed 21% CP with ZnO had increased (P = 0.001) ADG compared to those fed 18% CP (1.35% SID Lys) with high levels of feed grade amino acids or those fed the reduced SID Lys (1.2%) diet. Overall, G:F was improved (P < 0.001) for pigs fed 21% CP diets and those fed the 18% CP diet with NEAA compared to pigs fed 1.2% SID Lys and pigs fed high levels of feed grade amino acids. Fecal DM was increased for pigs fed the reduced SID Lys diet. In summary, pharmacological levels of Zn improve pig growth performance, but reducing CP (and subsequently SID Lys) decreased nursery pig growth performance.     

13～18周龄笼养蛋鸭适宜蛋白质和蛋氨酸水平的研究

用 32 4羽满 1 2周龄的金定鸭 ,通过饲养试验、代谢试验、屠宰试验和对试鸭产蛋期 (1 9～ 2 8周龄 )产蛋性能的观察 ,研究了在等能条件下(ME :1 1 51MJ/kg) ,不同蛋白质水平 (CP :1 3 %、 1 5 %、 1 7% )和蛋氨酸水平 (Met/CP :0 0 1 7、 0 0 2 2、 0 0 2 7)组成的 9种饲粮对 1 3～ 1 8周龄笼养蛋鸭的生长性能、养分利用、体成分沉积和产蛋期产蛋性能的影响。结果表明 :该阶段饲粮粗蛋白、蛋氨酸水平对体增重影响不显著 (P >0 0 5) ;体增重与蛋氨酸 (% )呈一定的正相关 (r=0 4574) ;CP为 1 3%、Met/CP为 0 0 2 7组采食量一直较稳定、较高 ,且饲料效率又好。代谢试验 :不同粗蛋白、蛋氨酸水平饲粮对试鸭氮存留率和能量的利用率影响显著(P <0 0 5或P<0 0 1 ) ,且它们随饲粮CP水平的升高而降低 ,随蛋氨酸水平升高而升高 ;磷的利用率也分别以CP为 1 3%的水平和Met/CP为 0 0 2 7的水平极显著地高于其他水平对磷利用率 (P <0 0 1 )。屠宰试验 :当Met/CP为 0 0 2 7时 ,体氮沉积量和体磷沉积量最佳。产蛋性能 :开产日龄和高峰日龄与 1 3～ 1 8周龄CP食入量呈弱的负相关 (r=- 0 1 83 3和r=- 0 0 984) ,与蛋氨酸食入量呈正相关 (r =0 5780和r =0 435 0 )。饲粮粗蛋白、蛋氨酸水平对 1 9～ 2 8周龄     

鹅饲用鸡肉骨粉的代谢能及常规营养成分代谢率研究

本文以鹅为试验动物,采用直接法和差量法研究鹅饲用鸡肉骨粉的营养价值.试验采用单因素完全随机设计,选取260日龄健康五龙鹅和青农灰鹅各42只(公),各设1个对照组和6个试验组,每组6个重复,试验鹅单笼饲养.对照组采用直接法,饲粮中不添加玉米淀粉;6个试验组采用差量法,分别在饲粮中添加15％、25％、45％、65％、75％、85％的玉米淀粉替代鸡肉骨粉.正试期3d,饲喂试验饲粮,然后排空24 h后,连续3d强饲无氮饲粮,每天强饲100 g,采用全收粪法.结果表明:1)五龙鹅和青农灰鹅品种内6个试验组的真代谢能(TME)及粗蛋白质(CP)、粗脂肪(EE)、部分氨基酸(AA)代谢率显著(P＜0.05)或极显著(P＜0.01)高于对照组;粗纤维(CF)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、钙(Ca)、磷(P)代谢率与对照组相比差异不显著(P＞0.05).2)差量法组间比较结果表明,75％玉米淀粉添加组五龙鹅和青农灰鹅的TME及CP、EE、部分AA代谢率均显著高于其他试验组(P＜0.05),85％玉米淀粉添加组的各项营养成分代谢率显著低于75％玉米淀粉添加组(P＜0.05).CF、NDF、ADF、Ca、P代谢率各组间差异不显著(P＞0.05).3)鸡肉骨粉对青农灰鹅TME及CP、部分AA代谢率显著(P＜0.05)或极显著(P＜0.01)高于五龙鹅;五龙鹅各组CF代谢率显著高于青农灰鹅(P＜0.05).试验表明,采用差量法测定鸡肉骨粉的鹅营养成分代谢率数据准确性较高,优于直接法,并且以75％玉米淀粉添加比例效果最好;鸡肉骨粉的鹅营养成分代谢率品种间存在一定的差异性.