大菱鲆幼鱼对玉米蛋白粉中营养物质的表观消化率及添加胆汁酸和酶制剂对其产生的影响

本试验旨在研究大菱鲆幼鱼对玉米蛋白粉中干物质、粗蛋白质、氨基酸和总能的表观消化率,以及在玉米蛋白粉中分别添加胆汁酸(纯度≥30%)和酶制剂[中性蛋白酶(1×105 U/g)和木瓜蛋白酶(4×105 U/g)组成的复合酶,二者活性比为2∶1]对其营养物质表观消化率的影响。首先配制基础饲料,试验饲料由70%的基础饲料和30%的待测蛋白质源[未进行任何处理的玉米蛋白粉(CGM)、添加胆汁酸的玉米蛋白粉(CGMB)和添加酶制剂的玉米蛋白粉(CGME)]组成。所有饲料均添加0.1%的三氧化二钇(Y2O3)为外源指示剂。将初始体重为(13.00±0.01)g大菱鲆幼鱼随机分为4组,每组3个重复,每个重复40尾鱼,分别投喂相应饲料2周后采用后肠挤压法收集粪便。养殖周期为10周。结果表明:3种不同处理形式的玉米蛋白粉中干物质、粗蛋白质、总氨基酸、总能的表观消化率分别为25.99%~43.34%、48.62%~60.72%、48.41%~67.67%、35.07%~52.34%,且总氨基酸与粗蛋白质表观消化率的变化趋势一致。其中,大菱鲆幼鱼对CGMB中各营养物质的表观消化率均最高,显著高于CGM和CGME(P0.05),且CGMB中干物质、粗蛋白质、总氨基酸、总能的表观消化率较CGM分别提高了17.35%、12.10%、19.26%、17.27%;大菱鲆幼鱼对CGME中各营养物质的表观消化率也得到改善,其干物质、粗蛋白质、氨基酸、总能的表观消化率较CGM分别提高了9.53%、4.37%、4.29%、12.25%,效果显著(P0.05)。由结果可知,添加胆汁酸和酶制剂均能够提高大菱鲆幼鱼对玉米蛋白粉中营养物质的表观消化率。     

吉富罗非鱼对5种蛋白源营养物质表观消化率的比较研究

试验旨在研究吉富罗非鱼(GIFT Tilapia,Oreochromis niloticus)幼鱼对鱼粉、豆粕、菜粕、棉粕、橡胶籽饼中干物质、粗蛋白质、粗脂肪、总磷、总能和氨基酸的表观消化率。试验饲料由70%基础饲料+30%待测原料组成,并以1.0%的三氧化二铬(Cr_2O_3)作为外源指示剂。选取平均体重为1.73 g/尾的吉富罗非鱼幼鱼,随机分为6组,每组3个重复,每个重复40尾鱼。投喂2周后通过虹吸法收集粪便。结果表明:(1)吉富罗非鱼幼鱼对饲料原料干物质、粗蛋白质、粗脂肪、总能、总磷和总氨基酸的表观消化率分别为:63.86%~73.66%、88.70%~93.15%、90.09%~94.27%、64.62%~73.47%、69.33%~86.46%和91.92%~94.80%;(2)5种饲料原料中鱼粉的干物质、粗蛋白质、总能和总磷的表观消化率最高,鱼粉、豆粕、菜粕中粗脂肪表观消化率高于棉籽粕和橡胶籽饼;(3)各饲料原料氨基酸的表观消化率基本维持在86.69%~96.81%之间,各原料氨基酸表观消化率的变化趋势与蛋白质表观消化率的趋势一致。由此可见,吉富罗非鱼幼鱼对鱼粉具有很好的利用效果,其次是菜粕、豆粕、棉籽粕、橡胶籽饼,且植物蛋白源之间的利用效率相当,可视为吉富罗非鱼幼鱼的优质植物蛋白源,在吉富罗非鱼幼鱼饲料中可适量添加,既有利于饲料的营养平衡,还可降低饲料成本。     

达氏鳇幼鱼对6种蛋白质原料中营养物质的表观消化率

为了解达氏鳇(Huso dauricus)幼鱼对不同蛋白质原料的消化能力,以0.4%的二氧化钛(TiO2)为指示剂,分别将鱼粉、鸡肉粉、肉骨粉、羽毛粉、双低菜粕和玉米蛋白粉这6种蛋白质原料与基础饲料按照3∶7的比例配制试验饲料,测定达氏鳇幼鱼对这6种蛋白质原料中干物质、粗蛋白质、粗脂肪、总能和总氨基酸的表观消化率。试验选取初始体质量为(66.79±2.18) g的达氏鳇幼鱼420尾,随机分为7组,每组3个重复,每个重复放鱼20尾。基础饲料投喂2周后,开始用试验饲料投喂,试验饲料投喂1周后采用捞网收集成形的粪便,共收集10 d。结果表明:达氏鳇幼鱼对鱼粉、鸡肉粉、肉骨粉、羽毛粉、双低菜粕和玉米蛋白粉这6种蛋白质原料中干物质、粗蛋白质、粗脂肪、总能和氨基酸的表观消化率分别为54.79%～88.07%、73.62%～89.47%、99.80%～100.74%、66.64%～89.24%、51.27%～98.62%。在6种蛋白质原料中,粗脂肪的表观消化率均在99%以上,而干物质、粗蛋白质和总能表观消化率则以鱼粉和鸡肉粉较高,玉米蛋白粉和双低菜籽粕次之,肉骨粉和羽毛粉较差。其中,鱼粉的粗蛋白质表观消化率最高,为89.47%,显著高于其他蛋白质原料(P0.05);鸡肉粉次之,为81.14%,与肉骨粉、双低菜籽粕和玉米蛋白粉差异不显著(P0.05);羽毛粉的粗蛋白质表观消化率最低,为73.62%,与肉骨粉差异不显著(P0.05),与其他蛋白质原料差异显著(P0.05)。各蛋白质原料中总氨基酸的表观消化率与粗蛋白质的表观消化率的变化趋势基本一致。由此可知,对于达氏鳇幼鱼饲料,鱼粉是最佳的蛋白质来源,鸡肉粉、玉米蛋白粉和双低菜籽粕亦可以作为其优质的蛋白质来源,而羽毛粉和肉骨粉作为蛋白质来源时,要控制其在饲料中的用量。     

鳙鱼对10种蛋白质饲料原料中营养物质的表观消化率

本试验旨在研究鳙鱼(Aristichthys nobilis)对鱼粉(国产)、干酒糟及其可溶物(DDGS)、菜籽粕、米糠、豆粕、酶解羽毛粉、棉籽粕、小麦麸、玉米蛋白粉和花生粕中干物质、粗蛋白质、粗脂肪、总能以及氨基酸的表观消化率。试验饲料按照基础饲料和待测饲料原料7∶3的比例构成,并添加0.5%的三氧化二钇(Y2O3)作为外源指示剂。挑选初体重为(290.02±2.82)g的鳙鱼,随机分成11组,每组3个重复,每个重复10尾鱼。随机选取1组作为对照组投喂基础饲料,剩余10组为试验组分别投喂试验饲料。投喂1周后通过虹吸法收集粪便。结果表明:1)10种饲料原料中干物质、粗蛋白质、粗脂肪和总能的表观消化率的范围分别为69.9%~85.7%、73.5%~88.3%、81.2%~91.1%和81.9%~86.3%。2)在10种饲料原料中,米糠总能的表观消化率最高,而鱼粉的干物质、粗蛋白质和粗脂肪的表观消化率最高;酶解羽毛粉的干物质、粗脂肪和总能的表观消化率最低,玉米蛋白粉的粗蛋白质的表观消化率最低。3)各饲料原料氨基酸的表观消化率基本维持在65.59%~99.17%,且都以小麦麸较低。由此可见,鳙鱼对鱼粉具有很好的利用效果,其次是豆粕和花生粕,而酶解羽毛粉中粗蛋白质的表观消化率最低,小麦麸各氨基酸的表观消化率均比较低。     

青鱼对8种饲料原料中营养物质的表观消化率

本试验旨在研究青鱼(Mylopharyngodon piceus)对国产鱼粉、蝇蛆粉、玉米蛋白粉、大豆粕、花生粕、棉籽粕、菜籽粕和米糠8种饲料原料干物质、粗蛋白质、氨基酸、粗脂肪、总磷和总能的表观消化率。试验饲料由70%基础饲料和30%待测饲料原料组成,并以0.1%的三氧化二钇(Y2O3)为外源指示剂。选取平均体重为(60.17±1.28)g的青鱼270尾,随机分成9组,每组3个重复,每个重复10尾鱼。对照组试验鱼饲喂基础饲料,试验组试验鱼分别饲喂1种试验饲料。饲喂1周后采用自排法收集粪便待测。结果表明:8种饲料原料的干物质、粗蛋白质、粗脂肪、总磷、总能以及总氨基酸的表观消化率的范围分别是62.17%～86.47%、83.34%～95.84%、78.93%～100.06%、37.33%～81.99%、66.75%～89.86%、86.33%～96.58%。在8种饲料原料中,玉米蛋白粉的干物质、总磷和总能的表观消化率最高,而大豆粕的粗蛋白质、粗脂肪和总氨基酸的表观消化率最高;棉籽粕的干物质和总能的表观消化率最低,米糠的粗脂肪和总磷的表观消化率最低。各饲料原料中总氨基酸表观消化率与粗蛋白质表观消化率的变化趋势一致,其中以蝇蛆粉最低。由此可见,大豆粕和玉米蛋白粉是青鱼的优质植物蛋白质源,可适量替代鱼粉;蝇蛆粉中粗蛋白质和氨基酸的消化率都较低,在青鱼饲料中的添加量不宜过高;花生粕、棉籽粕和菜籽粕也是较好的植物性蛋白质源,在青鱼饲料中适量添加既有利于饲料的营养平衡,还可降低饲料成本;米糠作为青鱼的能量原料必须保持新鲜,并控制其在饲料中的用量。     

建鲤对7种饲料原料中营养物质的表观消化率

本试验旨在研究建鲤(Cyprinus carpio var. Jian)对鱼粉、肉骨粉、豆粕、花生粕、棉籽粕、菜籽粕和玉米干酒糟及其可溶物(DDGS)7种常用饲料蛋白质原料中干物质、粗蛋白质、氨基酸、总磷和总能的表观消化率.营养物质表观消化率采用基础饲料(基础饲料Ⅰ、Ⅱ)和试验饲料(按基础饲料和待测原料7︰3的比例配制)测定,以0.5%的三氧化二铬(Cr2O3)为外源指示剂.选用平均体重为(200.0±4.7) g的建鲤240尾,随机分为8组,每组3个重复,每个重复10尾.从8组中随机选取1组为对照组,饲喂基础饲料;其余为试验组,饲喂试验饲料.试验分为2个阶段,第1阶段(1～4周)采用基础饲料Ⅰ,用于干物质、粗蛋白质、氨基酸和总能表观消化率的测定;第2阶段(5～8周)采用基础饲料Ⅱ,用于总磷表观消化率的测定.结果表明,各试验原料的干物质表观消化率在35.44%～71.10%之间,其中花生粕和豆粕的干物质表观消化率(分别为71.10%和65.15%)显著高于其他原料(P＜0.05).各试验原料的粗蛋白质表观消化率在60.31%～88.75%之间,其中豆粕的粗蛋白质表观消化率最高,而最低的为玉米DDGS,并且豆粕和花生粕的粗蛋白质表观消化率显著高于其他原料(P＜0.05).本研究中总磷的表观消化率相对较低,最高的为玉米DDGS(38.69%),最低的为肉骨粉(6.52%).从总体上来看,鱼粉、豆粕和花生粕的单个氨基酸及总氨基酸的表观消化率均处在较高水平,而肉骨粉和玉米DDGS的单个氨基酸及总氨基酸的表观消化率均处在较低水平.由此可知,对建鲤而言,豆粕和花生粕是较好的植物性蛋白质原料.     

吉富罗非鱼幼鱼对10种饲料原料表观消化率的研究

本试验以0.5%的三氧化二铬(Cr2O3)为指示剂研究吉富罗非鱼幼鱼对10种饲料原料的干物质、粗蛋白质、粗脂肪、磷、总能和氨基酸的表观消化率.10种饲料原料分别为玉米蛋白粉、玉米柠檬酸渣、玉米胚芽粕、普通豆粕、发酵豆粕、大豆浓缩蛋白、大豆分离蛋白、麦芽根、鱼粉和蚯蚓粉,试验日粮由70%的基础饲料和30%的试验饲料原料组成.选用初体重为(7.05±0.09)g的吉富罗非鱼苗495尾,随机分为11组,每组3重复,每个重复15尾鱼,其中对照组饲喂基础日粮,试验组分别饲喂1种试验日粮,收集的粪便样品待测.结果表明:10种饲料原料的干物质、粗蛋白质、粗脂肪、磷、总能和氨基酸的表观消化率范围分别为41.7%～98.9%、90.6%～99.6%、73.1%～98.8%、49.5%～99.6%、45.4%～99.7%和83.3%～100%.在10种饲料原料中,鱼粉、蚯蚓粉和大豆分离蛋白的干物质、粗蛋白质、总能表观消化率较高;玉米柠檬酸渣和蚯蚓粉的粗脂肪表观消化率较高;玉米胚芽粕和蚯蚓粉的磷表观消化率较高.蚯蚓粉的总能表观消化率最高,麦芽根的干物质、粗蛋白质、粗脂肪、总能表观消化率最低,大豆浓缩蛋白的磷的表观消化率最低.各原料氨基酸表观消化率的变化趋势与蛋白质表观消化率的趋势一致.由此可知,大豆分离蛋白、蚯蚓粉可视为鱼粉的优良动植物替代物,大豆浓缩蛋白、普通豆粕和发酵豆粕的营养价值略低于大豆分离蛋白、蚯蚓粉和鱼粉,麦芽根的营养价值最低.     

蓝狐对不同蛋白质来源日粮干物质和粗蛋白质表观消化率的比较研究

本试验测定了蓝狐对6种动物性蛋白(鸡肉粉、秘鲁鱼粉、鸡肠羽粉、肉骨粉、羽毛粉和猪肉粉)来源日粮和5种植物性蛋白(玉米蛋白粉、膨化大豆、豆粕、膨化玉米和玉米胚芽粕)来源日粮的干物质和粗蛋白质的表观消化率,比较了不同性别蓝狐对同一蛋白质来源日粮的干物质和粗蛋白质表观消化率差异.选取健康成年蓝狐公、母各110只,公、母狐分别随机分成11组,每组10个重复,每个重复1只.每组试验日粮的粗蛋白质由单一的试验饲料原料提供.预试期7 d,正试期3 d.结果表明,在6种动物性蛋白来源日粮中,羽毛粉日粮干物质表观消化率最高,但与鸡肉粉和秘鲁鱼粉日粮差异不显著(P>0.05);肉骨粉和猪肉粉日粮干物质表观消化率显著低于羽毛粉和鸡肉粉日粮(P<0.05).鸡肉粉日粮粗蛋白质表观消化率最高,但与秘鲁鱼粉、鸡肠羽粉和羽毛粉日粮差异不显著(P>0.05);猪肉粉和肉骨粉日粮粗蛋白质表观消化率显著低于鸡肉粉日粮(P<0.05).在5种植物性蛋白来源日粮中,膨化大豆日粮干物质表观消化率最高,但与豆粕日粮差异不显著(P>0.05);膨化玉米日粮的干物质表观消化率显著低于其他4种日粮(P<0.05).豆粕日粮的粗蛋白质表观消化率最高,但与膨化大豆和玉米蛋白粉日粮差异不显著(P>0.05);膨化玉米和玉米胚芽粕日粮的粗蛋白质表观消化率显著低于其他3种日粮(P<0.05).不同性别蓝狐对同一日粮的干物质和粗蛋白质表观消化率均差异不显著(P>0.05).由此得出,作为育成期蓝狐日粮的蛋白质来源,6种动物性蛋白原料中以鸡肉粉最佳,5种植物性蛋白原料中以豆粕最佳.不同性别蓝狐对同一日粮干物质和粗蛋白质表观消化率差异不显著.     

凡纳滨对虾对13种动物性饲料原料营养物质表观消化率的研究

本试验以三氧化二钇(Y2O3)为指示剂,由70%的基础饲料和30%的待测原料组成试验饲料,旨在研究凡纳滨对虾(Litopenaeus vannamei)对13种动物性饲料原料的营养物质表观消化率。13种动物性饲料原料分别为:白鱼粉(俄罗斯)、低温蒸汽红鱼粉(秘鲁)、国产直火干燥鱼粉、进口直火干燥鱼粉(秘鲁)、下杂鱼粉、血球蛋白粉、烘干血粉、鸡肉粉、肉骨粉、肉粉、酵解羽毛粉、水解羽毛粉和全虾粉。选取初始均重为(13.0±0.1)g的凡纳滨对虾1 260尾,随机分为14组,每组3个重复,每个重复30尾虾。各组对虾分别投喂相应试验饲料1周后,采用虹吸法收粪,测定干物质、粗蛋白质、粗脂肪、总能、总磷和氨基酸的表观消化率。结果表明:13种饲料原料的干物质、粗蛋白质、粗脂肪、总能、总磷和氨基酸的表观消化率范围分别为58.11%～76.91%、64.17%～93.57%、52.44%～95.62%、43.00%～95.21%、39.11%～76.47%和63.48%～94.06%。各饲料原料的氨基酸表观消化率与粗蛋白质表观消化率变化趋势基本一致。白鱼粉、低温蒸汽红鱼粉和进口直火干燥鱼粉的粗蛋白质表观消化率显著高于其他各饲料原料(P<0.05);酵解羽毛粉、水解羽毛粉和烘干血粉的粗脂肪表观消化率显著低于其他各饲料原料(P<0.05);白鱼粉和进口直火干燥鱼粉的总能表观消化率显著高于其他各饲料原料(P<0.05);白鱼粉、低温蒸汽红鱼粉、国产直火干燥鱼粉和进口直火干燥鱼粉的总磷表观消化率显著高于血球蛋白粉和烘干血粉(P<0.05)。13种动物性饲料原料中白鱼粉的干物质、总能和总磷的表观消化率最高,水解羽毛粉的干物质、粗蛋白质和总能的表观消化率最低,烘干血粉的粗脂肪和总磷的表观消化率最低。由此可见,不同来源和品质的鱼粉的营养物质表观消化率不同;鸡肉粉、肉骨粉、肉粉和全虾粉可作为凡纳滨对虾的优质蛋白质源,在实际生产中可部分替代鱼粉;羽毛粉和血粉由于所采用的加工工艺不同,其营养物质组成有所不同,导致表观消化率有一定的差异,在配制饲料前需对其进行营养价值的评定。     

中华鳖幼鳖对4种饲料原料中粗蛋白质和氨基酸的表观消化率

本试验旨在研究中华鳖(Trionyx sinensis)幼鳖对蚕蛹、发酵豆粕、肉骨粉和玉米蛋白粉4种饲料原料中粗蛋白质和氨基酸的表观消化率,以寻求中华鳖新型蛋白质饲料原料。试验饲料由70%的基础饲料和30%的待测饲料原料组成,并以0.5%的三氧化二铬(Cr2O3)作为外源指示剂。选取平均体重为(120.0±1.5)g的中华鳖幼鳖150只,随机分成5组(基础饲料组饲喂基础饲料,其他4组分别饲喂1种试验饲料),每组3个重复,每个重复10只,饲养1周后开始用虹吸法收集粪便,进行粗蛋白质和氨基酸表观消化率的测定。结果表明:1)中华鳖幼鳖对肉骨粉、发酵豆粕、蚕蛹中粗蛋白质的表观消化率分别为90.57%、86.34%、85.75%,显著高于玉米蛋白粉的75.98%(P<0.05)。2)动物性蛋白质源中,中华鳖幼鳖对蚕蛹中总氨基酸的表观消化率较高,为92.44%,对肉骨粉中总氨基酸的表观消化率较低,仅为82.48%;植物性蛋白质源中,中华鳖幼鳖对玉米蛋白粉中总氨基酸的表观消化率较高,为96.56%,对发酵豆粕中总氨基酸的表观消化率为87.90%。综合分析得出,蚕蛹可作为中华鳖幼鳖的优质动物性蛋白质源,发酵豆粕可作为中华鳖幼鳖较好的植物性蛋白质源。     

Milk yield and composition of lactating Comisana ewes fed total mixed rations containing nitrogen sources with different ruminal degradability

The objective of this study was to examine the effects of pelleted total mixed rations (PTMR) containing two crude protein (CP) levels and N sources with different ruminal degradability on milk yield and composition of lactating ewes. The experiment, which lasted 14 weeks, was conducted during the spring and summer of 2007 and used 80 multiparous Comisana ewes in mid-lactation, reared in permanent stabling. A 2 × 2 factorial design was used, with ewes receiving two levels of CP (low 15.5% CP and high 17.5% CP) and two type of N sources with different rumen degradable protein (low and high) for each dietary treatment: (1) high-degradable protein diet (17.5% CP) composed by soybean meal, sunflower meal and urea (HPHD), (2) low-degradable protein diet (17.5% CP) included only corn gluten meal (HPLD), (3) high-degradable protein diet (15.5% CP) composed by soybean meal, sunflower meal and urea (LPHD), and (4) low-degradable protein diet (15.5% CP) included only corn gluten meal (LPLD). In order to evaluate in vivo digestibility of PTMRs, four adult rams were placed in metabolic cages and their individual faeces and urine were collected. In the performance trial, ewe milk yield was recorded daily and Individual milk samples were analysed weekly for milk composition and to determine milk renneting parameters. The 17.5% CP diets led to better nutrient apparent digestibility coefficients and had positive effects on milk production than the 15.5% CP diets. Similar results were obtained for corn gluten meal diets, compared to diets containing soybean meal, sunflower meal and urea. Data showed that corn gluten meal diets have had a positive effects on milk fat (P < 0.05), but not on milk protein, lactose and renneting parameters. All ewes gained weight during the experimental period, but the body weight change was not significant among treatments. Our findings indicate that an increase in rumen undegradable protein (RUP) content does not negatively affect nutrient digestibility of sheep rations and milk yield and composition.     

Digestibility of amino acids in corn, corn coproducts, and bakery meal fed to growing pigs

The objectives of this experiment were to determine the apparent ileal digestibility and the standardized ileal digestibility (SID) of CP and AA in bakery meal, corn gluten meal, corn gluten feed, corn germ meal, and hominy feed and to compare these values with the apparent ileal digestibility and SID of CP and AA in corn and distillers dried grains with solubles (DDGS). Eight growing barrows (initial BW: 82.5 ± 5.5 kg) were randomly allotted to an 8 × 8 Latin square design with 8 diets and 8 periods. Diets contained corn, DDGS, bakery meal, corn gluten meal, corn gluten feed, corn germ meal, or hominy feed as the sole source of protein and AA. An N-free diet was used to measure basal endogenous losses of AA and protein. Pigs were fed experimental diets for eight 7-d periods, with ileal digesta being collected on d 6 and 7 of each period. Results indicated that the SID of Lys in corn gluten meal (78.7%) was greater (P < 0.01) than in DDGS, bakery meal, corn germ meal, and hominy feed (46.0, 48.4, 68.4, and 58.8%, respectively). The SID of all indispensable AA except Arg, Leu, and Met in bakery meal were not different from those in DDGS. The SID of Arg, His, Leu, and Met in corn gluten feed were less (P < 0.01) than in corn, but the SID of all other indispensable AA in corn gluten feed were not different from those in corn. However, for most indispensable AA, the SID in corn gluten feed was not different from the SID in DDGS. The SID of all indispensable AA in corn germ meal, except Arg, His, Leu, and Met, were not different from the SID in corn. Likewise, the SID of all indispensable AA in corn germ meal, except Arg and Leu, were not different from those in DDGS. The SID of Ile, Met, Phe, and Val in hominy feed were less (P < 0.01) than in corn, but the SID of the remaining indispensable AA in hominy feed were not different from the SID of indispensable AA in corn. All indispensable AA in hominy feed also had SID values that were not different from the SID values of AA in DDGS, except for Arg and Lys, which had greater (P < 0.01) SID than in DDGS. In conclusion, bakery meal had SID values of most AA that were less than in corn, but corn gluten meal had SID values for most AA that were greater than the SID of AA in corn, bakery meal, and corn coproducts.     

Chemical composition, protein quality, palatability, and digestibility of alternative protein sources for dogs

The chemical composition and protein quality of 11 alternative protein sources (chicken products, blood products, enzyme-hydrolyzed fish protein concentrate, soybean meal, and spray-dried pork liver) were determined, and an experiment was conducted to determine palatability and digestibility of processed red blood cell-containing diets. Chicken protein sources differed in concentrations of CP, acid-hydrolyzed fat, and total AA (TAA) by 20, 31, and 24%, respectively, and GE by 1.7 kcal/g. Blood protein sources varied little in acid-hydrolyzed fat and GE concentrations, but concentrations of CP and TAA differed by 11 and 8%, respectively. Protein solubility of chicken and blood protein source categories averaged 57 and 69%, respectively. Protein solubility of enzyme-hydrolyzed fish protein concentrate, soybean meal, and spray-dried pork liver was 53, 67, and 26%, respectively. Based on calculations from immobilized digestive enzyme assay values, lysine digestibility averaged approximately 80.4 and 81.7% for blood and chicken protein sources, respectively. Lysine digestibility values for soybean meal and spray-dried pork liver were 89 and 77%, respectively. A chick protein efficiency ratio (PER) assay showed that chicken protein sources had high protein quality values, as the PER ranged from 2.7 to 5.3, whereas blood protein sources had poor protein quality (PER values less than 1.5). Enzyme-hydrolyzed fish protein concentrate, spray-dried pork liver, and soybean meal had high protein quality (PER values greater than 2.8). In the dog palatability and digestibility experiments, a corn and chicken-based diet supplemented with either 0 or 3% processed red blood cells was tested. The palatability test showed that dogs consumed more of the diet that contained 0% vs. 3% processed red blood cells. The intake ratio for the 3% processed red blood cells diet was 0.34. Nutrient digestibilities did not differ, except for CP, where the digestibility was greater (P = 0.01) for dogs consuming the 0% processed red blood cells diet. These data suggest that chemical composition and quality of alternative protein sources differ greatly among ingredients within the same category. Palatability data suggest that a processed red blood cells-containing diet is not highly palatable but, when this diet was offered as only one food, dogs demonstrated no aversion response but some decrease in protein digestion.     

Nutritional value for swine of extruded corn and corn fractions obtained after dry milling

The experiment was designed to assess whether corn fractions or extrusion of corn can result in feed ingredients with a greater nutritional value than corn. Corn grain (8.0% CP, 0.21% P, 9.8% NDF) was processed by extrusion (82.8 degrees C, 345 kPa steam pressure for 12 s) or by dry milling to derive fractions rich in germ (13.1% CP, 1.19% P, 17.2% NDF), hulls (8.1% CP, 0.27% P, 32.6% NDF), and endosperm, namely tails (6.6% CP, 0.07% P, 3.6% NDF) and throughs (7.4% CP, 0.15% P, 4.5% NDF). Relative recovery in each fraction was 16, 20, 44, and 20%, respectively. Ileal digestibility of DM, P, and amino acids was determined using diets containing 7.0% CP from soybean meal and 5.3% CP from one of the test products. To allow for determination of standardized ingredient, ileal digestibility, basal endogenous AA losses were determined using a protein-free diet (74.6% cornstarch and 18.7% sucrose). Soybean meal ileal digestibility was determined using a diet (12.3% CP) based on soybean meal (23.3%). Eight barrows (27 +/- 2 kg) fitted with T-cannulas were fed 8 experimental diets (5-d adaptation and 2-d collection period) such that each diet was evaluated in at least 5 barrows. Relative to corn (77.9 +/- 1.2%), ileal digestibility of DM was greater for extruded corn (82.5%; P = 0.02), tails (85.9%; P < 0.01), and throughs (85.0%; P < 0.01), but it was lower for hulls (62.2%; P < 0.01) and germ (51.1%; P < 0.01). For P, corn (41.6 +/- 9.5%), throughs (47.2%), and hulls (57.3%) had similar ileal digestibility, but germ (7.9%) had lower ileal digestibility (P = 0.02) than corn; tails (27.6%) and extruded corn (23.5%) were not different from corn or germ but were lower than throughs and hulls. For total AA, corn (84.7 +/- 2.4%), throughs (84.3%), and hulls (85.8%) had similar ileal digestibility, but germ (76.6%) had lower ileal digestibility (P < 0.01) than corn; tails (82.0%) and extruded corn (81.7%) were intermediate. In conclusion, germ and hulls have a low ileal DM digestibility; germ also has low AA and P digestibility. Extrusion improved the ileal DM digestibility of corn. To maximize the ileal digestibility, removal of germ and hull from corn or extrusion of corn may thus be of interest.     

高植物蛋白质饲料中添加丁酸钠对大菱鲆幼鱼生长性能、营养物质表观消化率及肝脏抗氧化功能的影响

本试验旨在研究高植物蛋白质饲料中添加丁酸钠对大菱鲆幼鱼生长性能、营养物质表观消化率及肝脏抗氧化功能的影响,探索提高水产饲料中植物蛋白质替代鱼粉比例的可行性方法。以鱼粉、豆粕、玉米蛋白粉、谷朊粉、花生粕和啤酒酵母为蛋白质源,鱼油、椰子油和大豆卵磷脂为脂肪源,小麦粉为糖源,配制5种等氮等能的试验饲料。其中,以含60%鱼粉的基础饲料为阳性对照组(FM组),以复合植物蛋白质源替代基础饲料中50%鱼粉的替代饲料为阴性对照组(CON组),以在替代饲料中分别添加0.15%(D1组)、0.30%(D2组)和0.60%(D3组)丁酸钠的饲料为试验组。用上述5种试验饲料分别饲喂初始体重为(13.00±0.01)g的大菱鲆幼鱼58d,试验在室内养殖系统中进行,每种试验饲料投喂3个重复,每个重复30尾鱼。结果表明:1)随着丁酸钠添加水平的增加,大菱鲆幼鱼的增重率、特定生长率和饲料效率呈现先升高后降低的趋势,其中FM、D1和D2组增重率、饲料效率和特定生长率显著高于CON组(P0.05),而各组间摄食率无显著差异(P0.05);除D2组脏体比与FM组无显著差异(P0.05)外,其他各组的脏体比均显著低于FM组(P0.05);各组全鱼水分、粗蛋白质和粗脂肪含量无显著差异(P0.05)。2)D1组干物质表观消化率显著高于CON组(P0.05),与FM组无显著差异(P0.05);D1组蛋白质表观消化率显著高于CON、D2和D3组(P0.05),与FM组无显著差异(P0.05);D2和D3组之间干物质和蛋白质表观消化率差异不显著(P0.05)。3)D2组肝脏总抗氧化能力(T-AOC)和过氧化氢酶(CAT)活性显著高于CON组(P0.05),肝脏丙二醛(MDA)含量显著低于CON组(P0.05)。由此得出,在本试验条件下,高植物蛋白质饲料中添加0.15%的丁酸钠能够提高大菱鲆幼鱼的生长性能、营养物质表观消化率和肝脏抗氧化功能,过量添加丁酸钠会降低大菱鲆幼鱼的生长性能。     

肉牛常见饲料干物质和蛋白质瘤胃降解特性和小肠消化率研究

[方法]选用装有瘤胃瘘管和小肠瘘管的肉牛作为试验动物,尼龙袋法测定肉牛常见饲料干物质(DM)和粗蛋白(CP)的瘤胃降解特性和小肠消化率。[结果]结果表明,DM瘤胃有效降解率由高到低为玉米粉、麦麸、苜蓿干草、豆粕、菜籽粕、玉米青贮、醋糟、白酒糟;CP瘤胃有效降解率由高到低为苜蓿干草、麦麸、豆粕、醋糟、玉米粉、玉米青贮、菜籽粕、白酒糟;DM小肠消化率由高到低为豆粕、菜籽粕、玉米粉、白酒糟、醋糟、麦麸、苜蓿干草、玉米青贮;CP小肠消化率由高到低为豆粕、菜籽粕、玉米粉、苜蓿干草、麦麸、白酒糟、玉米青贮、醋糟。[结论]试验表明,不同饲料瘤胃降解特性不同,为小肠提供过瘤胃可消化蛋白的能力不同,且饲料的DM小肠消化率小于CP小肠消化率。     

Influence of dietary protein and carbohydrate sources on nitrogen metabolism and carbohydrate fermentation by ruminal microbes in continuous culture

Four diets containing 15% CP were formulated to study the effects of dietary carbohydrate and protein sources on N metabolism and carbohydrate fermentation by ruminal bacteria. Diets were supplied to eight dual-flow continuous culture fermenters during three experimental periods in a randomized complete block design. Six replications were obtained for each diet. Treatments were arranged as a 2 X 2 factorial with two carbohydrate and two protein sources. Carbohydrate sources were corn and barley and protein sources were soybean meal (SBM) and fish meal (FM). Approximately 40% of the dietary CP was derived from SBM or FM and corn or barley provided 39% of dietary DM. All diets contained 15% grass hay, 20% wheat straw, and 10.1 to 15.3% solka floc (DM basis). Interactions (P less than .05) were observed between dietary carbohydrate and protein sources, resulting in a depression of VFA production (moles/day) and digestion (percentage) of ADF and cellulose when the corn-FM diet was fed. True OM digestion (percentage) was higher (P less than .05) for SBM than for FM diets and for corn than for barley diets. Although dietary CP degradation (percentage) was higher (P less than .05) for SBM than for FM diets, non-NH3 N in the effluent (grams/day) was not different among diets due to a greater (P less than .05) bacterial N flow for SBM than for FM diets. Despite the lower amino acid (AA) intake (P less than .05) for corn than for barley diets and also for FM than for SBM diets, flows (grams/day) of total AA, essential AA (EAA), and nonessential AA (NEAA) were similar (P greater than .05) among diets. However, greater (P less than .05) total AA, EAA, and NEAA flows (percentage of AA intake) were found for corn than for barley diets and for FM than for SBM diets. It is concluded, therefore, that ruminal escape protein derived from corn or FM has a significant effect on manipulating AA leaving the ruminal fermentation.