黑鲷幼鱼赖氨酸需求量的研究

选用初体重(9.13±0.09)g的黑鲷(Sparus macrocephalus)幼鱼360尾随机分为6组,每组3个重复,每个重复20尾,分别投饲赖氨酸水平实测值为2.08%、2.52%、2.88%、3.25%、3.68%和4.05%的等氮等能日粮.试验期为8周,观察日粮赖氨酸对黑鲷生长性能,体组成以及消化能力的影响,并确定其适宜的赖氨酸需求量.结果表明,当饲料中的赖氨酸水平从2.08%上升到3.25%,黑鲷的增重率和特定生长率随着饲料赖氨酸水平升高而升高(P<0.05),此后则出现降低的趋势.赖氨酸低水平组(2.08%和2.52%)饲料效率较其他组低(P<0.05),其余各组之间没有显著性差异(P>0.05).饲料赖氨酸水平从2.08%上升到3.25%,蛋白质沉积率有显著提高(P<0.05),此后趋于稳定.存活率与肝体比与赖氨酸水平无关.全鱼蛋白质含量随饲料赖氨酸水平增加而增加,脂肪含量则呈现下降趋势;各组间的灰分和水分含量没有显著性差异(P>0.05).肝脏总必需氨基酸和赖氨酸含量随着饲料赖氨酸水平升高而增加,但是在赖氨酸添加水平最高组这两个指标均有所降低(P<0.05).随着饲料赖氨酸含量增加,血清胆固醇含量、谷丙转氨酶(ALT)和谷草转氨酶(AST)活性呈下降趋势,赖氨酸含量为3.68%时均达最低值,而对血清甘油三酯含量没有显著性影响(P>0.05).赖氨酸含量为3.25%时,干物质和蛋白质的表观消化率最高,而脂肪消化率的最高值出现在3.68%赖氨酸的饲料组.试验结果还表明,黑鲷幼鱼胃、前肠和中肠的蛋白酶活性变化趋势基本一致.随着饲料中赖氨酸水平的增加而升高(P<0.05),过高的饲料赖氨酸水平则会降低蛋白酶活性,各组间的胃、前肠和中肠的脂肪酶活性先下降后升高(P<0.05),饲料赖氨酸水平对黑鲷幼鱼胃、前肠和中肠的淀粉酶活性没有显著影响(P>0.05).使用曲线模型,根据试验黑鲷幼鱼的增重率同饲料中赖氨酸水平的相关性得出其赖氨酸需要量为3.28%,占饲料蛋白质的8.63%.     

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。     

L-赖氨酸硫酸盐对南美白对虾生长和消化的影响

初始体质量为1.0g的南美白对虾按饲养试验要求分为3组。试验1组和试验2组分别在基础日粮中添加0.26%L-赖氨酸盐酸盐和0.39%L-赖氨酸硫酸盐,按产品中的赖氨酸含量计算,2组赖氨酸含量均为0.2%。结果表明,与基础日粮组相比,添加L-赖氨酸硫酸盐使虾的增重率、特定生长率、蛋白质效率、干物质和粗蛋白消化率分别提高了13.95%(P<0.05)、5.98%(P>0.05)、13.33%(P<0.05)、8.56%(P<0.05)和8.89%(P<0.05)。L-赖氨酸盐酸盐也有提高生长性能和饲料养分表观消化率的趋势,但差异不显著。     

不同蛋白质水平日粮对荣×大×杜生长猪生产性能和养分消化率的影响

试验选用90头25kg左右荣×大×杜杂交猪,随机分3个处理,每个处理6个重复,每个重复5头猪,分别饲喂可消化赖氨酸水平相同,蛋白质水平分别为16.0%、15.0%、14.0%的三种不同日粮(对照组、试验1组、试验2组),考察氨基酸平衡模式下不同蛋白质水平日粮对生长猪生产性能及养分消化率的影响及其经济效益分析。试验结果表明:(1)各组日采食量基本接近,试验1组日增重最高、料重比最低,日增重比对照组高44.2g/d,料重比较对照低4.3%,但未达到显著差异(P0.05),试验2组的日增重、料重比与对照组接近。(2)干物质表观消化率,试验2组比对照组高1.31%(P0.05),试验1组与对照组差异不显著(P0.05);粗蛋白质表观消化率,各组间基本接近,均未达到显著差异(P0.05);钙表观消化率,试验1、2组分别比对照组高13.7%(P0.05)、9.03%(P0.05);磷、粗灰分表观消化率,各组间基本接近,未达到显著差异。(3)试验1组和试验2组,单位增重饲料成本较对照组分别降低0.42元/kg、0.23元/kg。结果表明,按照猪理想蛋白氨基酸平衡模式来配制日粮,将荣×大×杜三元土杂猪的生长猪日粮蛋白质水平降低至15%或14%,不仅不影响其生产性能,还可降低单位增重饲料成本,提高了养猪经济效益。综合生产性能、养分消化率以及经济效益指标,日粮氨基酸平衡条件下,荣×大×杜生长猪的适宜蛋白质水平为15%。     

65%赖氨酸硫酸盐在肉鸡中消化率的测定

试验选用64羽平均体重为(3.73±0.10)kg健康爱拔益加成年肉公鸡,测定了赖氨酸硫酸盐和赖氨酸盐酸盐的赖氨酸消化率。将试验鸡随机分为4个处理,每个处理4个重复,每个重复4羽。处理1为绝食组;处理2为酪蛋白组;处理3为酪蛋白日粮添加赖氨酸硫酸盐组;处理4为酪蛋白日粮添加赖氨酸盐酸盐组。分别采用酪蛋白法和绝食法测定氨基酸的内源损失。结果表明:①利用酪蛋白法和绝食法测定的内源损失差异不显著(P>0.05);②赖氨酸硫酸盐的赖氨酸表观消化率为87.75%,利用酪蛋白法和绝食法测得的真消化率分别为99.34%和98.64%;③赖氨酸盐酸盐的赖氨酸表观消化率为87.81%,利用酪蛋白法和绝食法测得的真消化率分别为99.37%和98.67%。综上可得,采用酪蛋白法和绝食法测定的氨基酸内源损失无显著性差异;赖氨酸硫酸盐与赖氨酸盐酸盐的赖氨酸消化率差异不显著。     

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。     

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.     

饲料赖氨酸水平对鳜幼鱼生长、饲料利用及生化组成的影响

文章旨在研究饲料添加不同水平赖氨酸对鳜幼鱼生长、饲料利用及生化组成的影响。试验选取平均体重为（2.75±0.08）g的鳜幼鱼540尾,随机分为6组,每组3个重复,分别饲喂赖氨酸水平D1组（1.52）（%干重,下同）、D2组（1.88）、D3组（2.16）、D4组（2.58）、D5组（3.02）、D6组（3.49）的等氮等能饲料。结果表明,饲料添加不同水平的赖氨酸可提高鳜幼鱼的终末体重、日增重、增重率及特定生长率。在终末体重上,D4组显著高于D1组、D2组、D3组（P＜0.05）。日增重D4组显著高于D1组、D2组、D3组和D6组（P＜0.05）,D5组和D6组差异不显著（P＞0.05）。增重率和特定生长率D4组显著高于D1组、D2组、D3组（P＜0.05）。饲料系数D4组显著低于D1组、D2组、D3组差异显著（P＜0.05）。不同赖氨酸水平对鱼体蛋白质、脂肪、水分无显著影响（P＞0.05）,鱼体中灰分水平随各组赖氨酸水平增加有升高趋势,但各组差异不显著（P＞0.05）。综上所述,鳜幼鱼饲料中赖氨酸水平为2.90%,占饲料蛋白质的5.58%,生长和饲料利用效果较好。 [关键词]鳜幼鱼|赖氨酸|生长|饲料利用|生化组成     

饲料粒度和工艺对花鲈幼鱼生长性能、抗氧化能力、营养物质消化率及肠绒毛结构的影响

试验旨在研究饲料粉碎粒度和加工工艺对花鲈幼鱼生长性能、抗氧化能力、营养物质消化率和肠绒毛结构的影响。选择初始体重(10.14±0.12)g的健康花鲈(Lateolabrax japonicus)幼鱼420尾,随机分为4组。在56 d的饲养期间分别投喂4组不同粉碎粒度和加工工艺饲料,即60目制粒(Z60)、80目制粒(Z80)、60目膨化(P60)和80目膨化(P80)饲料。结果表明,各组间花鲈的末均重、增重率、特定生长率、成活率、日采食量、饲料系数、肥满度均无显著差异(P0.05)。P60和P80组花鲈蛋白质效率、脏体比和肝体比均高于Z60和Z80组(P0.05)。各组间花鲈全鱼体组成、血清生化、肝脏抗氧化指标均无显著差异(P0.05)。P60和P80组干物质表观消化率高于Z60和Z80组(P0.05),Z80组干物质表观消化率高于Z60组(P0.05)。P60和P80组粗蛋白质表观消化率高于Z60组(P0.05)。P60和P80组粗脂肪表观消化率高于Z60和Z80组(P0.05)。粗灰分表观消化率P80P60Z80Z60(P0.05)。P80和Z80分别较P60和Z60绒毛形态规则,P80绒毛长度和杯状细胞数显著高于Z60和Z80(P0.05)。综上所述,饲料粉碎粒度对花鲈生长性能和营养物质表观消化率无显著影响,饲料粒度越小,肠道绒毛形态越规则。膨化工艺提高了花鲈蛋白质效率、脏体比和肝体比,增加了饲料干物质与营养物质表观消化率,改善了花鲈幼鱼肠道绒毛形态结构。     

黄颡鱼幼鱼的赖氨酸需要量

为评估饲料中赖氨酸水平对黄颡鱼幼鱼生长性能、营养成分和血液指标的影响,进而确定黄颡鱼幼鱼的赖氨酸需要量,试验设计6种等氮等脂的饲料(粗蛋白质45.00%,粗脂肪7.00%),饲料中晶体赖氨酸的添加水平分别为0、0.30%、0.60%、0.90%、1.20%和1.50%,实测各饲料中赖氨酸水平分别为1.58%、1.89%、2.15%、2.41%、2.67%和2.90%。试验选取初始体重为2.00 g左右的黄颡鱼幼鱼360尾,随机分为6组,每组3个重复,每个重复20尾,进行为期12周的养殖试验。结果表明:1.58%组黄颡鱼幼鱼的成活率显著低于其他各组(P0.05)。黄颡鱼幼鱼的增重率和特定生长率随着赖氨酸水平的增加呈先升高后降低趋势,且在赖氨酸水平为2.41%时具有最大的增重率和特定生长率。饲料效率和蛋白质效率均以1.58%组最低,显著低于除2.15%组外的其他各组(P0.05)。饲料中赖氨酸水平对黄颡鱼幼鱼的肥满度、肝体比和内脏比无显著影响(P0.05)。饲料中赖氨酸水平对全鱼和肌肉干物质、粗脂肪含量以及肌肉粗蛋白质含量均无显著影响(P0.05),但显著影响全鱼和肌肉粗灰分含量以及全鱼粗蛋白质含量(P0.05),全鱼和肌肉粗灰分含量均以2.41%组最低,全鱼粗蛋白质含量以2.41%组最高。饲料中赖氨酸水平对黄颡鱼幼鱼全血中红细胞数、白细胞数、血红蛋白含量、红细胞压积无显著影响(P0.05),对血清中总胆固醇、葡萄糖含量及谷草转氨酶活性亦无显著影响(P0.05),但对血清中谷丙转氨酶活性和甘油三酯含量有显著影响(P0.05)。以增重率为评价指标,通过线性模型分析得出黄颡鱼幼鱼对饲料中赖氨酸的需要量为2.61%(相当于饲料蛋白质的5.80%)。     

Utilization of dipeptide/protein based diets in larval and juvenile Koi carp – post‐prandial free amino acid levels

We have shown previously that diets in which the nitrogen portion is based on synthetic dipeptides (PP) resulted in weight gain by rainbow trout alevins when free amino acid (FAA) based diets did not. However, the protein‐based diet used as a control in the previous study resulted in a significantly better performance of fish than peptide‐ or FAA based diet fed fish. Therefore, the objectives of our study were (i) to test how stomachless fish respond to peptide‐based diets, (ii) to evaluate PP and protein‐PP mixture diets and (iii) to examine if post‐prandial response to FAA concentrations in the fish body can be used as an indicator of the availability of dietary amino acid sources. The first experiment was conducted with a 4‐day old Koi carp (Cyprinus carpio) larvae and included groups fed a casein–gelatin (CG) based diet, a commercial diet and live Artemia nauplii. In the second experiment, fish fed live Artemia for 3 weeks (69 ± 12 mg) were placed in glass aquaria in triplicate per dietary treatment. Four diets provided equivalent amounts of nitrogen in the form of a CG, a PP, a 50% PP and 50% CG (PP50) mix and as FAA. Fish were fed at 1 and 3 h intervals, and the survival and growth were monitored during the second and third weeks of experiments 1 and 2 respectively. Following the completion of feeding, juvenile carp were sampled prior to feeding and 3 h after a meal. Whole body FAA analyses were carried out. We observed marginal suitability of the CG diet for larval Koi carp, as earlier indicated in common carp. Juvenile Koi carp fed the CG diet achieved 236 ± 19 mg, whereas PP50, PP and FAA diet fed fish grew to 140 ± 37, 70 ± 8 and 73 ± 5 mg respectively. Free amino acids in the fish body, and in particular indispensable amino acids (IDAA), were excellent indicators of dietary availability. The present experiment shows that a dietary 1:1 ratio of protein to synthetic PPs results in better growth, survival and whole body IDAA concentrations in relation to FAA‐ and PP‐based diets confirming earlier reports on the use of synthetic PP‐based diets, although this diet does not match the performance of complete protein, CG‐based diet.     

A Comparative Study of the Difference Method and the Enzyme-Hydrolyzed Casein Method for Determining True Amino Acid Digestibilities and Endogenous Amino Acid Losses in Duck Feed

In this study, we examined the variations between the difference method and the enzyme-hydrolyzed casein method for determining endogenous amino acid loss and the true amino acid digestibility in ducks fed normal protein-containing diets. These methods were compared to the nitrogen-free (N-free) diet method. The difference method was based on soybean meal as the only protein source, with the experimental diets containing crude protein levels at 15% and 20%. The enzyme-hydrolyzed casein method was based on enzyme-hydrolyzed casein meal as the protein source, with the experimental diet containing a crude protein level of 17.5%. The N-free diet was prepared with starches and paper fibers. In each method, 64 Tianfu meat drakes (7-weeks-old) with an average body weight of 2.77 ± 0.16 kg were used and divided into four groups, and fed four different diets. Each group contained four replicates of four drakes and they were force fed trial diets according to the Sirbald method for detecting their apparent amino acid digestibility, endogenous amino acid loss and true amino acid digestibility. The results demonstrated that using the difference, enzyme-hydrolyzed casein and N-free diet methods, endogenous amino acid losses were 0.9946, 1.2243 and 0.9297 mg/g dry matter intake (DMI), respectively. The true amino acid digestibility measured by the difference method was 88.93% ± 4.43%. Using the enzyme-hydrolyzed casein method with two dietary crude protein levels of 15% and 20%, the digestibility was 91.15% ± 4.33% and 91.97% ± 4.16%, respectively, and by the N-free diet methods with two dietary crude protein levels of 15% and 20%, it was 88.55% ± 4.29% and 88.82% ± 4.61%, respectively. The results suggested that when the dietary protein level was 15% to 20 %, the true amino acid digestibility and endogenous amino acid loss as determined by the difference method was more accurate than the values determined by the enzyme-hydrolyzed casein method.     

A Comparative Study of the Difference Method and the Enzyme-Hydrolyzed Casein Method for Determining True Amino Acid Digestibilities and Endogenous Amino Acid Losses in Duck Feed

In this study,we examined the variations between the difference method and the enzyme-hydrolyzed casein method for determining endogenous amino acid loss and the true amino acid digestibility in ducks fed normal protein-containing diets.These methods were compared to the nitrogen-free(N-free)diet method.The difference method was based on soybean meal as the only protein source,with the experimental diets containing crude protein levels at 15% and 20%.The enzyme-hydrolyzed casein method was based on enzyme-hydrolyzed casein meal as the protein source,with the experimental diet containing a crude protein level of 17.5%.The N-free diet was prepared with starches and paper fibers.In each method,64 Tianfu meat drakes(7-weeks-old)with an average body weight of 2.77±0.16 kg were used and divided into four groups,and fed four different diets.Each group contained four replicates of four drakes and they were force fed trial diets according to the Sirbald method for detecting their apparent amino acid digestibility,endogenous amino acid loss and true amino acid digestibility.The results demonstrated that using the difference,enzyme-hydrolyzed casein and N-free diet methods,endogenous amino acid losses were 0.9946,1.2243 and 0.9297 mg/g dry matter intake(DMI),respectively.The true amino acid digestibility measured by the difference method was 88.93%±4.43%.Using the enzyme-hydrolyzed casein method with two dietary crude protein levels of 15% and 20%,the digestibility was 91.15%±4.33% and 91.97%±4.16%,respectively,and by the N-free diet methods with two dietary crude protein levels of 15% and 20%,it was 88.55%±4.29% and 88.82%±4.61%,respectively.The results suggested that when the dietary protein level was 15% to 20 %,the true amino acid digestibility and endogenous amino acid loss as determined by the difference method was more accurate than the values determined by the enzyme-hydrolyzed casein method.     

Apparent and true amino acid digestibility of a crystalline amino acid mixture and of casein: comparison of values obtained with ileal-cannulated pigs and cecectomized cockerels.

Six ileal-cannulated pigs that averaged 100 kg BW and 16 adult cecectomized cockerels that averaged 2.35 kg BW were used to determine apparent and true digestibilities of amino acids (AA) in a complete crystalline AA mixture and in casein. A protein-free (PF) diet was included as a treatment to estimate endogenous AA losses. Fasted cockerels were compared to cockerels fed PF diets for calculation of true digestibility of AA in cockerels. For the AA diet, true digestibility of indispensable AA in the pig ranged from a low of 97.2% for leucine to a high of 100.5% for arginine (Arg). True digestibility of indispensable AA in casein ranged from a low of 93.5% for isoleucine (Ile) to a high of 99.9% for Arg. Correcting for endogenous losses increased digestibilities of lysine (Lys) and threonine (Thr) in pigs fed the AA diet by 2.4 and 7.1%, respectively, and increased Lys and Thr digestibility in pigs fed the casein diet by 1.8 and 6.1%, respectively. Feeding a PF diet to chickens to correct for endogenous losses resulted in higher true digestibility values for all AA with the exception of tryptophan, methionine, and Arg than those obtained using fasted animals. True digestibilities of Thr were 88.3 and 86.6% for AA and casein diets, respectively, using fasted controls but were 97.5 and 94.5% when the PF control was used. Proline digestibility was increased (P < .05) substantially in both pigs and cockerels when the PF control was used to correct for endogenous AA losses. Regardless of species, Ile in casein had a lower true digestibility value than any other indispensable AA. The results of this study indicated that true digestibilities of AA in a mixture of crystalline AA and in casein are essentially 100% in both pigs and cockerels.     

低蛋白质饲粮中苏氨酸水平对离乳前期梅花鹿仔鹿生长性能和营养物质表观消化率的影响

本试验旨在研究低蛋白质饲粮中苏氨酸水平对离乳前期梅花鹿仔鹿生长性能和营养物质表观消化率的影响。选择24只健康无病的3月龄雄性梅花鹿,随机分为4组,每组6只。4组仔鹿限量饲喂4种不同的饲粮,各组饲粮赖氨酸、蛋氨酸水平均分别为0.87%、0.28%。其中,高蛋白质饲粮对照组(Ⅰ组)仔鹿饲喂蛋白质水平为16%的高蛋白质饲粮,低蛋白质饲粮试验组(Ⅱ~Ⅳ组)仔鹿饲喂蛋白质水平为14%并添加不同水平苏氨酸的低蛋白质饲粮,各组饲粮中苏氨酸水平分别为0.54%(Ⅰ组)、0.46%(Ⅱ组)、0.59%(Ⅲ组)、0.72%(Ⅳ组)。预试期为15 d,正试期为30 d。结果表明:1)高蛋白质饲粮对照组的平均日增重(ADG)极显著高于Ⅱ组(P0.01),与Ⅲ、Ⅳ组差异不显著(P0.05);高蛋白质饲粮对照组的料重比(F/G)极显著高于Ⅲ、Ⅳ组(P0.01),极显著低于Ⅱ组(P0.01)。2)高蛋白质饲粮对照组的粗蛋白质表观消化率极显著低于Ⅲ和Ⅳ组(P0.01),极显著高于Ⅱ组(P0.01);高蛋白质饲粮对照组能量表观消化率极显著低于Ⅲ、Ⅳ组(P0.01),与Ⅱ组无显著差异(P0.05);Ⅲ组钙表观消化率极显著高于Ⅱ组(P0.01),与其他组差异不显著(P0.05)。3)高蛋白质饲粮对照组的组氨酸、天冬氨酸、谷氨酸、甘氨酸、半胱氨酸表观消化率显著高于Ⅱ组(P0.05),与Ⅱ组其他氨基酸表观消化率无显著差异(P0.05);高蛋白质饲粮对照组赖氨酸、蛋氨酸、苏氨酸、精氨酸、丙氨酸、酪氨酸表观消化率极显著低于Ⅲ组(P0.01),缬氨酸、亮氨酸、苯丙氨酸、丝氨酸表观消化率显著低于Ⅲ组(P0.05);高蛋白质饲粮对照组除丙氨酸的表观消化率极显著低于Ⅳ组(P0.01)以及赖氨酸、苏氨酸、缬氨酸、丙氨酸表观消化率显著低于Ⅳ组(P0.05)外,其他氨基酸的表观消化率与Ⅳ组无显著差异(P0.05)。由此得出,低蛋白质饲粮中适宜水平的苏氨酸对离乳前期梅花鹿仔鹿的生长性能和营养物质消化利用具有促进作用;当饲粮赖氨酸、蛋氨酸水平相同时,饲喂蛋白质水平为14%、苏氨酸水平为0.59%的低蛋白质饲粮的梅花鹿仔鹿的生长性能和营养物质表观消化率均优于饲喂蛋白质水平为16%的高蛋白质饲粮的梅花鹿仔鹿。     

低蛋白质日粮补充赖氨酸、蛋氨酸对离乳期梅花鹿氮代谢的影响

为研究低蛋白质日粮添加赖氨酸和蛋氨酸对仔鹿氮代谢的影响,采用4×4完全拉丁方试验,选取3月龄、健康、离乳梅花鹿仔鹿4只,体重为(30±0.12)kg(X?±SD),进行消化代谢试验。对照组(Ⅰ组)饲喂16.28%粗蛋白质的高蛋白质日粮,试验组饲喂13.40%粗蛋白质,添加0.23%赖氨酸,并分别添加0(Ⅱ组)、0.06%(Ⅲ组)、0.12%(Ⅳ组)蛋氨酸的低蛋白质日粮。结果表明:1)对照组蛋白质消化率显著高于Ⅱ组(P<0.01)、Ⅲ组和Ⅳ组(P<0.05),脂肪消化率显著低于Ⅱ组(P<0.01),其他营养物质消化率差异不显著(P>0.05)。2)对照组和Ⅳ组蛋氨酸消化率显著高于Ⅱ组和Ⅲ组(P<0.05),对照组其余氨基酸消化率(赖氨酸、胱氨酸除外)显著高于各试验组(P<0.05)。3)对照组吸收氮显著高于Ⅱ组(P<0.01)、Ⅲ组和Ⅳ组(P<0.05),尿氮排放量显著高于各试验组(P<0.05),氮利用率及氮生物学效价低于各试验组(P>0.05)。4)对照组尿嘌呤衍生物总排放量显著大于Ⅱ组(P<0.01)和Ⅲ组(P<0.05),尿囊素显著大于Ⅱ组(P<0.01)、Ⅲ组和Ⅳ组(P<0.05),对照组、Ⅲ组和Ⅳ组黄嘌呤和次黄嘌呤显著高于Ⅱ组(P<0.01)。补充赖氨酸、蛋氨酸可改善低蛋白质日粮仔鹿营养物质消化率利用率,除粗蛋白外其他营养物质消化率与常规蛋白质水平相近,甚至更好,提高氮沉积、氮利用率和生物学效价,改善氮平衡,减少氮排放,降低环境污染。     

豌豆分离蛋白和豌豆浓缩蛋白替代部分鱼粉对鲤鱼生长性能的影响

分别采用豌豆分离蛋白和豌豆浓缩蛋白替代饲料中33%、66%和100%鱼粉(对照组鱼粉10%)配制与对照组等氮、等能、等赖氨酸、等蛋氨酸和有效磷的试验饲料(其中豌豆分离蛋白用量3%、6%和9%,豌豆浓缩蛋白用量4.5%、9%和13.5%),饲养初始体重(18.53±0.35)g的建鲤75 d。结果表明:豌豆分离蛋白替代100%鱼粉组增重和特定生长率显著高于、饲料系数显著低于对照组(P<0.05),其余处理组与对照组间差异不显著(P>0.05)。两种豌豆蛋白替代鱼粉对成活率、肥满度和肠长指数无显著影响(P>0.05),但显著影响肝胰脏指数,其中豌豆分离蛋白替代100%鱼粉组和豌豆浓缩蛋白组显著低于对照组(P<0.05)。豌豆浓缩蛋白替代100%鱼粉组可观察到对适口性有不良影响。由上述结果可得出,豌豆分离蛋白和豌豆浓缩蛋白均可作为鲤鱼料的蛋白源,本试验条件下,以生长性能为标识结合适口性推荐豌豆分离蛋白可完全替代鱼粉,适宜用量9%;豌豆浓缩蛋白可替代33%鱼粉,适宜用量4.5%。     

草鱼幼鱼对缬氨酸需要量的研究

试验选用体重(9.5±0.3)g的草鱼幼鱼,随机分成6个组,每组3个重复,每个重复20尾;以花生仁粕、酪蛋白及明胶为蛋白质源,分别饲喂缬氨酸水平为7.3～22.3 g/kg的6组等氮半精制饲料(粗蛋白质含量为32%),经70 d的生长试验研究其日粮缬氨酸的最适需求量.试验结果表明:日粮缬氨酸水平对草幼鱼的增重率、特定生长率、蛋白质效率、肌肉RNA/DNA比率、鱼体常规成分组成、消化酶活性、肝胰脏谷草-谷丙转氨酶和谷氨酸脱氢酶活性以及血液学指标都有显著的影响(P<0.05).随日粮缬氨酸水平的增加,增重率,特定生长率、蛋白质效率及肌肉RNA/DNA比率均呈先升后降趋势,均在16.3 g/kg组达到最大值(P<0.05).以增重率、特定生长率、肌肉RNA/DNA比率为基础对饲料缬氨酸水平进行二次回归分析,确定草鱼幼鱼日粮(32%粗蛋白质)缬氨酸适宜需要量分别为15.6、15.1及16.0 g/kg(日粮基础)或48.8、47.2及50.0 g/kg(日粮蛋白质基础).     

蚯蚓粪营养组成及其对异育银鲫增重率的影响

本试验将120尾异育银鲫随机分成2组:对照组投喂基础日粮,试验组在基础日粮中添加5%蚯蚓粪。连续投喂60d后,测定蚯蚓粪营养成分、氨基酸含量及鱼体增重率。结果表明,蚯蚓粪中含水分22.6%、粗蛋白质12.44%、粗脂肪0.86%、灰分35.88%、碳水化合物27.74%、总氨基酸6.06%、必需氨基酸为2.48%(占总氨基酸的39.81%),其中可提高适口性的天门冬氨酸、谷氨酸、丙氨酸及甘氨酸等含量也相对较多。生长试验表明:与对照组相比,饲喂5%蚯蚓粪异育银鲫增重率比对照组显著提高29.75%(P<0.05)、饵料系数显著降低23.77%(P<0.05),并降低了死亡率。