加州鲈对15种饲料原料体外消化率的测定

采用"胃-肠"两步法测定了加州鲈(Micropterus salmoides)对15种饲料原料的体外消化率,并与银鲈(Bidyanus bidyanus)体内消化率数据进行了比较。结果表明:加州鲈对秘鲁鱼粉、喷干血粉、豆粕、花生麸、玉米蛋白粉、酵母膏、破壁酵母7种原料的体外消化率较高(干物质>45%,蛋白质>71%),对玉米、DDGS消化率较低(干物质<17%,蛋白质<61%),且大部分原料的体内、外消化率结果具有极显著的相关性(P<0.01)。体外消化率的结果可为加州鲈饲料原料的选择提供参考依据。     

梭鲈、河鲈和加州鲈的肌肉营养成分分析

对梭鲈、河鲈和加州鲈的肌肉营养成分进行分析与比较。结果表明,河鲈的水分含量略高于梭鲈和加州鲈;梭鲈、河鲈和加州鲈蛋白质(鲜质量比)分别为19.94%、18.73%和18.39%;3种鱼中,梭鲈的粗脂肪含量最少,而灰分含量差异不明显。肌肉中17种氨基酸的总含量由大到小的顺序依次是梭鲈(19.40%)>河鲈(18.09%)>加州鲈(17.99%),必需氨基酸(EAA)含量依次为梭鲈(7.08%)>加州鲈(6.58%)>河鲈(6.55%),鲜味氨基酸含量梭鲈(7.42%)>加州鲈(6.84%)>河鲈(6.83%)。可见,3种鱼是肉质鲜美、营养丰富而且经济性状好,是值得推广的养殖品种。     

混合植物蛋白质替代鱼粉对花鲈和西伯利亚鲟生长和肉质影响的比较研究

通过16周的生长试验,比较研究混合植物蛋白质替代鱼粉对花鲈(Lateolabrax japoni-cus)和西伯利亚鲟(Acipenser baeri Brandt)生长和肉质的影响。2种试验鱼的对照组饲料均以低温蒸汽干燥鱼粉(白鱼粉)作为唯一蛋白质源,花鲈对照组饲料含56.9%的白鱼粉,粗蛋白质含量为40%,命名为LJ-FM;西伯利亚鲟对照组饲料含51.0%的白鱼粉,粗蛋白质含量为36%,命名为AB-FM。以混合植物蛋白质(豆粕∶谷元粉为1.00∶1.67,粗蛋白质含量为64.84%)在等氮等能的基础上分别替代对照组饲料中25%、50%、75%、100%的鱼粉,并相应命名为LJ-PPB25、LJ-PPB50、LJ-PPB75、LJ-PPB100和AB-PPB25、AB-PPB50、AB-PPB75、AB-PPB100。花鲈的初始体重为(7.34±0.01)g,随机分为5组,每组设4个重复,每个重复30尾;西伯利亚鲟的初始体重为(49.48±1.00)g,随机分为5组,每组设4个重复,每个重复22尾。结果表明:混合植物蛋白质替代鱼粉后,花鲈的摄食率显著下降(P<0.05);末均重以LJ-PPB25组最高,显著高于LJ-PPB75和LJ-PPB100组(P<0.05);LJ-PPB100组的饲料系数显著高于其他4组(P<0.05);混合植物蛋白质替代鱼粉后,花鲈全鱼的水分和粗灰分含量显著升高(P<0.05),粗脂肪含量显著下降(P<0.05),粗蛋白质含量和总能无显著变化(P>0.05)。各组西伯利亚鲟的摄食率、末均重、饲料系数及体成分均无显著差异(P>0.05)。同一替代水平下,西伯利亚鲟肌肉中各个游离氨基酸含量均远高于花鲈。一定水平(≤75%)的混合植物蛋白质替代鱼粉能显著提高花鲈肌肉中总游离氨基酸和呈味氨基酸的含量以及西伯利亚鲟肌肉中总游离氨基酸和必需氨基酸的含量(P<0.05)。对于花鲈,摄食含混合植物蛋白质饲料后肌肉中游离组氨酸(生物胺的前体物)含量显著增加(P<0.05);而西伯利亚鲟肌肉中游离组氨酸含量却随混合植物蛋白质替代水平的上升呈先升高后降低的趋势,以AB-PPB100组最低,显著低于除AB-PPB75组外的其他各组(P<0.05)。随着混合植物蛋白质替代水平的上升,花鲈肌肉游离氨基酸中牛磺酸含量先升高后降低,以对照组最低,显著低于除LJ-PPB100组外的其他各组(P<0.05);但对西伯利亚鲟没有显著影响(P>0.05)。2种试验鱼鲜鱼片的质构特性差异较大,但熟鱼片差异较小。混合植物蛋白质替代鱼粉后对2种试验鱼鲜鱼片和熟鱼片质构特性的影响均不显著(P>0.05)。2种试验鱼鲜鱼片的剪切力差异较大,西伯利亚鲟要远高于花鲈,但二者均未随着混合植物蛋白质替代水平的上升而发生显著变化(P>0.05)。2种试验鱼鲜鱼片中胶原蛋白含量差异较小,且随着混合植物蛋白质替代水平的上升均呈现先上升后下降的趋势,并均在替代水平为25%时达到最高值。混合植物蛋白质替代鱼粉对花鲈鲜鱼片的滴水损失没有显著影响(P>0.05),但降低了西伯利亚鲟鲜鱼片的滴水损失,且在替代水平为50%和100%时差异达到显著水平(P<0.05)。LJ-PPB25组花鲈的肌纤维密度显著低于LJ-PPB100组(P<0.05),但AB-PPB25组与AB-PPB100组间西伯利亚鲟的肌纤维密度无显著差异(P>0.05)。根据生长及肉质结果,花鲈饲料中混合植物蛋白质替代鱼粉的水平不宜高于50%。混合植物蛋白质完全替代鱼粉不影响西伯利亚鲟的生长,但考虑肉质指标建议最高替代水平为75%。     

新型棉籽蛋白的氨基酸消化率测定

选用6头公猪,用简单T-型瘘管法,以普通棉粕为对照,测定了新型棉籽蛋白的氨基酸消化率。结果表明,同普通棉粕相比,新型棉籽蛋白的蛋白质含量提高,氨基酸含量也相应提高,粗纤维含量降低;新型棉籽蛋白的氨基酸和蛋白质消化率高于普通棉粕,脯氨酸、组氨酸、谷氨酸、总必需氨基酸、总氨基酸和粗蛋白的消化率显著提高(P<0.05),赖氨酸的消化率极显著提高(P<0.01)。     

35日龄断奶仔猪消化试验

本文利用 35日龄断奶仔猪对鱼粉、喷雾干燥血浆粉、浸出豆粕和经膨化后的浸出豆粕 4种蛋白质饲料进行了粗蛋白质和氨基酸的消化率测定。结果表明 :4种日粮的粗蛋白质表观消化率分别是81 .54%、86 .55%、76 .6 6 %和 79.86 % ;可消化粗蛋白含量分别是 1 4 .6 3%、1 5.53%、1 2 .2 7%和 1 4 .3% ;蛋白质净利用率分别是 6 6 .91 %、6 8%、6 1 .7%、6 4.4 0 % ;蛋白质生物学价值分别是 81 .4 2 %、78.51 %、73.2 2 %和 74 .87% ;4种日粮的赖氨酸表观消化率分别是 93.80 %、93.4 0 %、89.97%和 88.87%。通过本消化试验说明 ,该试验所用的血浆粉作为仔猪日粮的蛋白饲料原料与鱼粉效果相当 ,甚至优于鱼粉 ,为此在研制早期断奶仔猪全价日粮配方时可把血浆粉作为一种很好的蛋白饲料原料     

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。     

我国饲用鱼粉进口存在问题及解决途径

鱼粉是配合饲料中的一种优质动物性蛋白质原料,其蛋白质含量可达45～67%,蛋白质消化率在90%左右;鱼粉蛋白质中氨基酸品种较齐全,含量较高,尤其是赖氨酸、蛋氨酸、亮氨酸等比其它蛋白质原料丰富。由于鱼粉含有4～12%的脂肪酸,极易氧化变质发出热量,甚至会产生自燃现象,因而给仓储、运输带来一定困难。在世界鱼类捕获总量中,大约有三分之一(约8000万吨)不能为人类直接利用。这部分鱼类资源大部分被加工成鱼粉和鱼油。进入70年代后,世界每年渔获物加工成约500万吨的鱼粉和100     

南美白对虾对四种蛋白质原料的离体消化率和酶解动力学研究

采用离体消化法和茚三酮法研究了南美白对虾(Penaeus vannamei)的胃、肝胰脏及肠道粗酶液对鱼粉、豆粕、菜粕和花生粕的离体消化率和酶解动力学。结果表明:①在离体状态下,南美白对虾消化道不同部位对干物质消化率为:胃>肝胰脏>肠道,且鱼粉在胃部的消化率显著高于肝胰脏和肠道(P<0.01),花生粕在肠道的消化率极显著低于胃和肝胰脏(P<0.01);对蛋白质消化率为肝胰脏>胃>肠道,且菜粕和花生粕在肠道的消化率极显著低于胃和肝胰脏。鱼粉差异显著(P<0.05)。②粗酶液对4种原料干物质的总消化率高低依次为:豆粕50.78%、菜粕42.02%、花生粕39%、鱼粉36.50%;对粗蛋白总消化率高低依次为:花生粕60.40%、豆粕56.45%、鱼粉46.28%、菜粕43.28%。③粗酶液对4种蛋白原料酶解时所产生氨基酸的生成量随着酶解时间的变化具有一定的线性关系;在0～4h内在酶解过程中所产生氨基酸的总量为肝胰脏(96.72mg)>胃(31.28mg)>肠道(27.58mg);酶解时氨基酸生成总速度为花生粕(3.9154mg/h)>鱼粉(3.4774mg/h)>豆粕(2.8316mg/h)>菜粕(2.7404mg/h)。     

改进离体消化方法对四种鱼粉的质量鉴定和分析

采用改进的离体消化法研究草鱼(Ctenopharyngodonidellus)对俄罗斯鱼粉、国产鱼粉1、国产鱼粉2、罗非鱼鱼粉1和罗非鱼鱼粉2的消化能力,结果显示,2种国产鱼粉粗蛋白质含量(72.14%、68.26%)、蛋白质消化率(49.78%、49.41%)均显着高于俄罗斯鱼粉(65.41%、47.82%),且0h时水解液中氨基酸总量显着高于俄罗斯鱼粉;2种罗非鱼鱼粉虽然粗蛋白质含量(56.03%、52.69%)相对较低,但它们的氨基酸生成量与俄罗斯鱼粉相近。研究表明:两种国产鱼粉中掺入了可以溶解的高含氮物质;罗非鱼鱼粉可以作为饲料原料被较好的利用;此方法可以对鱼粉真伪和蛋白质有效利用效果进行鉴定。     

花鲈对6种饲料原料的表观消化率

采用Y2O3作为外源指示剂,以70%基础饲料和30%待测饲料原料配制试验饲料,测定初始体质量为(23.30±0.32)g的花鲈对鱼粉(FM)、豆粕(SBM)、花生粕(PNM)、棉粕(CSM)、菜籽粕(RSM)和玉米DDGS干物质、粗蛋白、粗脂肪、总能、磷和氨基酸的表观消化率。结果表明,花鲈对6种饲料原料干物质的表观消化率在33.85%~75.08%,其中PNM、CSM、RSM和DDGS与FM相比分别显著降低(P0.05)。对粗蛋白的表观消化率为88.10%~94.55%,其中FM显著高于CSM(P0.05)。对粗脂肪的表观消化率超过75%,CSM与FM相比显著降低(P0.05),SBM和DDGS显著低于其他各种饲料原料(P0.05)。对磷的表观消化率为29.03%~87.39%,其中SBM显著高于其他各饲料原料(P0.05)。花鲈对FM总能的表观消化率显著高于其他各饲料原料(P0.05),对CSM总能的表观消化率与其他原料相比显著降低(P0.05)。花鲈对氨基酸的表观消化率范围为47.27%~98.90%,其中对SBM和PNM氨基酸的表观消化率与FM最为接近。结果表明,花鲈对PNM和SBM的干物质、粗蛋白、磷、总能和氨基酸的表观消化率与FM比较接近,可以作为饲料中替代FM的植物蛋白源。     

去盲肠和未去盲肠公鸡测定饲料氨基酸消化率的比较研究

应用Sibbald“TME”方法,比较了去盲肠和未去盲肠公鸡对饲料氨基酸的消化率。试验测定了10种饲料的去盲肠和未去盲肠公鸡的氨基酸消化率。结果表明,未去盲肠鸡对10种饲料的氨基酸表观和真消化率均高于去盲肠鸡。轻度受热鱼粉、重度受热鱼粉、脱毒棉籽饼、未脱毒棉籽饼和豆饼的表观氨基酸消化率在去盲肠鸡和未去盲肠鸡之间存在显著差异(P<0.05),未受热鱼粉和芝麻饼的表观氨基酸消化率在去盲肠鸡和未去盲肠鸡之间不存在显著差异(P>0.05)。轻度受热鱼粉、重度受热鱼粉、豆饼的真氨基酸消化率在去盲肠鸡和未去盲肠鸡之间存在显著差异(P<0.05);未受热鱼粉、脱毒棉籽饼、未脱毒棉籽饼和芝麻粕的真氨基酸消化率在去盲肠鸡和未去盲肠鸡之间不存在显著差异(P>0.05)。去盲肠鸡内源氨基酸排出量显著高于未去盲肠鸡(P>0.05)。微生物对未消化食糜中的肽类、氨基酸具有降解作用。     

Comparative protein and amino acid digestibilities in growing pigs and sows.

An experiment was conducted to compare apparent total tract protein digestibilities and apparent ileal digestibilities of protein and amino acids in growing pigs and adult pregnant and lactating sows. Twelve growing pigs and 12 sows were used and surgically fitted with simple T-cannulas at the distal ileum. Six experimental diets based on corn, barley, wheat, soybean meal, canola meal, or meat and bone meal were formulated, and each diet was fed to growing pigs, gestating sows, and lactating sows for 7 d. Chromium oxide was included in all diets as an indigestible marker (.25%) for calculating nutrient digestibilities. Fecal material was collected on d 5 of each feeding period by grab sampling, and ileal samples were collected for 12 h/d during the last 2 d of each feeding period. Apparent fecal protein digestibilities for all feed ingredients were higher (P < .05) in gestating and lactating sows compared to growing pigs, but no differences between the two groups of sows were observed (P > .05). At the distal ileum, no differences (P > .05) in protein digestibilities were detected between sows and growing pigs regardless of feed ingredient. For all feed ingredients tested, lactating sows had apparent ileal digestibilities of most amino acids that were two to six percentage units higher than those obtained in growing pigs, but not all of the differences were significant. Gestating sows had digestibilities of most amino acids that were intermediate between those of growing pigs and lactating sows. The combined results from the six feed ingredients showed that lactating sows had higher (P < .05) digestibilities of all indispensable amino acids except arginine, and gestating sows had higher (P < .05) digestibilities of five of the indispensable amino acids than did growing pigs. The results of this experiment indicate that apparent fecal protein and apparent ileal amino acid digestibilities obtained in growing pigs are not always representative of digestibilities in either gestating or lactating sows.     

The effect of feed intake on ileal rate of passage and apparent amino acid digestibility determined with or without correction factors in pigs

The apparent ileal digestibilities of amino acids and rate of passage were evaluated in pigs (BW = 78.3 +/- 7.4 kg) fed a semipurified diet. The pigs were fed 1.82, 2.73, or 3.65 kg DMI/d. The highest level of feed intake was considered to be ad libitum feeding. The pigs were fed according to a 3 x 3 Latin square design and were allowed to adapt to each experimental diet for 5 d. This was followed by 1 d of continuous collection of ileal digesta and a 2nd d of continuous collection separated into six 2-h postprandial time blocks. Ytterbium chloride hexahydrate was used to determine rate of passage. The ileal digestibilities of amino acids and rate of passage were unaffected (P > 0.05) by level of feed intake. The use of correction factors to more accurately express amino acid concentrations in the diet and digesta affected (P < 0.05) the apparent ileal digestibility coefficients of some amino acids.     

鸡与鸭饲料氨基酸消化率测定值比较

本研究应用排空强饲法及石岐杂公鸡、樱桃谷公鸭分别测定定了5种饲料氨基酸表观消化率和真消化率。结果表明：除玉米氨基酸表观消化率外,其余饲料的大多数氨基酸消化率在鸡和鸭之间都存在着明显差异;在32小时收粪时间里,鸭的内源氨基酸排出量明显比鸡多;内源氨基酸对鸡和鸭的饲料氨基酸真消化率都有影响,影响大小随蛋白质含量高低而异,一般饲料蛋白质含量越低的饲料两者相差越大。而内源氨基酸排出量对鸭饲料,尤其对低蛋白含量饲料的氨基酸真消化率的影响比鸡更明显。     

Yttrium oxide (Y2O3) as an inert marker in digestibility studies with dogs, blue foxes and mink fed diets containing different protein sources

The study evaluated the use of yttrium oxide (Y(2)O(3)) as an inert marker in studies of apparent total tract digestibility in dogs, blue foxes and mink. Comparison was made with total faecal collection, and use of chromic oxide (Cr(2)O(3)) as marker respectively. Four experimental diets were added 0.1 g/kg yttrium oxide and 10 g/kg chromic oxide and fed to four animals of each species. Faecal recovery of yttrium oxide was 94.4% (SEM +/- 1.0), and of chromic oxide 105.8% (SEM +/- 1.5). The digestibilities of dry matter, crude protein, crude fat, starch and total carbohydrates obtained by total collection and yttrium oxide as marker showed close similarity, and in most cases not significant differences, independent of species and diets. In dogs, overall digestibilities of main nutrients with chromic oxide as marker were not significantly different from overall means obtained with yttrium oxide (p > 0.05). Overall digestibility of dry matter, crude protein and total carbohydrates in blue foxes and mink was significantly higher with chromic oxide than with yttrium oxide (p < 0.05). In dogs and blue foxes, digestibilities of individual amino acids determined by use of yttrium oxide were not different from values obtained using total collection of faeces, both within diets and for overall mean (p > 0.05). Overall amino acid digestibilities in dogs determined with chromic oxide as marker were similar to corresponding figures for yttrium oxide, whereas use of chromic oxide resulted in significantly higher digestibilites for a number of amino acids compared with yttrium oxide in foxes and mink (p < 0.05). The digestibilities of most main nutrients and amino acids revealed no interaction between diet and method (p > 0.05). The study showed that yttrium oxide can be used in low concentration in the feed, and allows high accuracy of analyses and thereby precise digestibility determination. It is concluded that yttrium oxide is an alternative inert marker to chromic oxide in the studied species.     

应用Sibbald“TME”方法测定鸡饲料氨基酸利用率的研究

饲料氨基酸利用率的测定是进行可利用氨基酸营养研究的一项基础性工作。本研究利用去盲肠公鸡,应用Sibbald“TME”方法,测定了玉米、次粉、高粱、菜籽饼、棉籽饼、棉仁粕、胡麻饼、豆饼、豆粕、鱼粉、豌豆蛋白粉、绿豆蛋白粉、蚕豆蛋白粉的氨基酸表观和真消化率。氨基酸平均真消化率超过90%的依次为豆粕、蚕豆蛋白粉、鱼粉、绿豆蛋白粉、豌豆蛋白粉。消化率低于85％、高于80％的依次为高粱、玉米、次粉,消化率低于80％的依次为棉仁粕、豆饼、菜籽饼、胡麻饼、棉籽饼。所测饲料各氨基酸的平均真消化率大于85％的依次为谷氨酸、异亮氨酸、精氨酸、门冬氨酸、亮氨酸、苯丙氨酸、酪氨酸;消化率在80％～85％之间的依次为丝氨酸、缬氨酸、蛋氨酸、丙氨酸;小于80％的依次为苏氨酸、赖氨酸和胱氨酸。研究结果表明,不同饲料和不同氨基酸之间消化率存在很大的差异。内源氨基酸排泄量对低蛋白饲料氨基酸利用率存在较大的影响。适当的加工处理对于提高饼粕类饲料的氨基酸消化率具有重要意义。     

Ileal digestibility of amino acids in pigs fed barleys differing in protein content

The apparent digestibility of nitrogen and amino acids was measured by the ileal and faecal methods in pigs fed nine barleys differing in nitrogen content (from 1.73 to 2.16 per cent/DM). A positive (r = 0.87) and significant relationship was found between the apparent nitrogen digestibility at the end of the ileum and the crude protein content of barley. Generally, the higher the protein of the grain, the higher the ileal digestibilities of the amino acids. For most amino acids the faecal values were greater than the ileal ones. This being specially so for threonine, tryptophan, histidine and cystine belonging to the nutritionally important amino acid group. When the relationship between the amino acid and nitrogen digestibilities at the level of ileum is considered, the values were found to be similar to that of nitrogen in the case of tryptophan, higher for isoleucine, valine (both 2-3 units), cystine, histidine, leucine, methionine (all 5-6 units) and phenylalanine (10 units) and lower only for lysine and threonine (7-8 dig. units).     

Substitution of milk protein with isolated soy protein in calf milk replacers

The influence of replacement of milk protein by isolated soy protein on digestion and pancreatic enzyme secretion was determined in nine Holstein male calves. Calves (average weight 47 kg) were fitted with permanent re-entrant pancreatic and a T-type cannula in the distal ileum at 6 to 10 d of age. Following a 2-wk recuperation period, the calves were fed three milk replacers in a triplicated 3 x 3 latin square. Experimental diets consisted of a control, in which 100% of the CP originated from spray-dried skim milk powder (SM), and the test diets, in which 50% (SM/ISP) or 100% (ISP) of the skim milk protein was replaced by isolated soy protein. Each experimental period lasted 2 wk. Replacement of SM protein by ISP decreased (P less than .05) the digestibilities of protein and most amino acids. Ileal digestibilities of total indispensable amino acids for SM, SM/ISP and ISP diets were 82.1, 75.8 and 61.8%, respectively, and total tract digestibilities of total indispensable amino acids were 90.0, 82.6 and 74.0%, respectively. Including ISP did not affect (P greater than .05) the volume of secretion of pancreatic juice, protein or chymotrypsin; however, the secretion of trypsin decreased (P less than .05). Reduction in trypsin secretion may be responsible, in part, for the lower amino acid digestibilities in milk replacers containing isolated soy protein.     

Effects of dietary protein levels on digestibility of nutrients and growth rate in young female mink (Mustela vison)

This study investigated digestibilities of nutrients and feed efficiency in female mink at the different dietary protein levels during the mink growth period. Effects of dietary protein on growth performance of minks were also measured. Sixty 45‐day‐old healthy female minks were randomly assigned to 6 treatment groups with 10 animals in each group. Animals were fed diets varying in protein levels: 28% (Group I), 30% (Group II), 32% (Group III), 34% (Group IV), 36% (Group V) and 38% (Group VI), respectively. The digestibilities of key nutrients were determined on Day 14 after initiating the experiment and the last 3 days. From the beginning of the study, body weight and feed intake were weighed and recorded every other week in order to calculate the average daily bodyweight gain and the feed efficiency. The trial had demonstrated that nitrogen intake was greatly significantly different, which was affected by dietary protein levels (p < 0.001). Growth performance of minks was impaired when dietary protein level was at 28%. When dietary protein level was at 34%, minks had the best daily gains, feed efficiency, and digestibilities of some key nutrients.