猪用3种常规植物性饲料磷有效率的测定

本试验采用4×4拉丁方设计,用玉米、豆粕和麦麸替代低磷基础饲粮的方法配制待测饲粮,以平衡试验法测定了生长猪对3种饲料总磷的表观消化率和沉积率。结果表明以总磷和非植酸磷含量估测饲料有效磷并不准确。玉米、豆粕和麦麸总磷表观消化率分别为20.14%±1.97%、31.42%±3.32%、49.83%±2.50%,总磷沉积率分别为19.49%±1.91%、31.22%±3.30%、49.74%±2.46%。     

生长猪植物性饲料中可消化磷的评定

采用4×4拉丁方设计 ,用玉米淀粉—豆粕作为基础饲粮 ,运用替代基础饲粮的方法测定了生长猪对一些植物性饲料中磷的消化吸收情况 ,并分析了饲料的总磷、植酸磷含量和饲料植酸酶(E.C.3.1.3.26)活性的高低与饲料表观可消化磷的关系。试验结果表明 ,生长猪对以下几种饲料磷的表观消化率如下 :次粉 ,(54.43±3.41) % ;麦麸 ,(50.67±3.96) % ;小麦 ,(49.11±3.37) % ;大麦 ,(42.06±2.12) % ;豆粕 ,(30.83±3.66) % ;玉米 ,(18.99±4.11) % ;细米糠 ,(14.22±2.00) % ;统糠 ,(10.60±3.28) %。试验结果的分析表明 :饲料的总磷含量(X,g/kgDM)、植酸磷含量(Y,g/kgDM)、饲料天然植酸酶活性(Z,PU/g DM)对饲料的表观可消化磷含量(ADP ,g/kgDM)的影响极显著(P<0.01) ,并有极显著的回归关系 :ADP= -0.4155+0.7972X -0.7802Y +0.0013Z(R2=0.9767,P=0.001)。     

不同含磷矿物质饲料中磷相对生物学利用率的研究

以玉米—豆粕型日粮(表观代谢能12.21MJ/kg、粗蛋白质20 %、总钙1.0 %、非植酸磷0.21 %)为基础 ,采用斜率比法 ,以饲料级磷酸氢钙为参照物测定饲料级磷酸二氢钙、饲料级骨粉和自制脱氟磷酸钙的相对生物学利用率。选择新生AA品种肉用仔鸡(公母各半)和伊萨褐蛋用仔公鸡各192只 ,各随机等分为12个处理组 ,每处理组设4个重复 ,随机给饲由4种参试物分别配制成非植酸磷水平各自为0.21 %、0.31 %、0.41 %的12种试验日粮 ,试验日粮除总磷和非植酸磷水平外 ,其它各项指标与基础日粮保持一致。试验结果表明 ,含磷矿物质饲料种类影响其相对生物学利用率 ,4种参试物中磷的相对生物学利用率以饲料级磷酸二氢钙最高 ,其次是饲料级磷酸氢钙、骨粉 ,脱氟磷酸钙最低 ,分别约为饲料磷酸氢钙的101.9 %～139.0 %、100 % ,75.7 %～106.7 %和69.9 %～89.1 % ;试验鸡类型(肉仔鸡或蛋用仔公鸡)不影响含磷矿物质饲料相对生物学利用率的测值 ;衡量指标不同导致含磷矿物质饲料相对生物学利用率的测值不同 ,其中以体增重最高 ,胫骨灰分含量最低 ,趾骨灰分含量居中。     

磷的标准全肠道消化率和真消化率评定及其可加性研究

试验旨在比较使用磷的标准全肠道消化率(STTD)和真消化率(TPD)评定生长猪对玉米和豆粕中磷的利用效率及其是否具有可加性。选用56头平均体重为(30.5±0.8)kg的三元杂种去势公猪随机分为7个处理,每个处理8个重复,每个重复1头猪。对照组(无磷饲粮)用于测定猪的内源磷排泄量,6个试验饲粮按2×3因子试验设计,包含2个磷水平(低磷0.14%或高磷0.24%)和3种待测饲料原料(玉米、豆粕以及玉米豆粕混合物)。结果表明,随饲粮磷水平的提高,生长猪总磷日摄入量、粪磷日排泄量和日可消化磷均极显著增加(P0.01)。生长猪采食低磷饲粮和高磷饲粮测得玉米、豆粕以及玉米豆粕混合物中磷标准全肠道消化率(STTD)分别为42.06%和41.11%、48.73%和48.43%、44.38%和44.23%。低磷饲粮和高磷饲粮组玉米豆粕混合物中磷STTD计算值分别为44.28%和43.55%,与测定值44.38%和44.23%相比无显著差异(P0.05)。线性回归法测得玉米、豆粕以及玉米豆粕混合物磷的真消化率(TPD)为40.71%、49.83%和44.21%。玉米豆粕混合物TPD计算值为43.75%,与测定值44.21%相比差异不显著(P0.05)。由此可见,使用磷STTD和TPD用于生长猪玉米豆粕型饲粮配制时均具有较好的可加性。     

成年蛋鸡内源磷测定方法的研究

试验以豆粕为唯一磷源,配制一组梯度磷水平饲粮,总磷水平分别为0.74、1.55、2.30、3.10 g/kg DM,同时设无磷日粮作为对照。采用Sibbald强饲技术,利用无磷日粮法、线性回归法或差量法测定成年蛋公鸡内源磷排泄量。结果表明,在磷水平低于鸡的磷营养需要量的条件下,磷摄入量和排泄量间存在线性关系,线性回归法或差量法测得的鸡内源磷与无磷日粮法的测定结果一致;海兰父母代公鸡内源磷排泄量为204 mg/kg DMI,豆粕总磷的真利用率为53.60%。     

麦麸饲粮添加无机磷对生长猪生产性能和养分消化率的影响

选用长白×雅南杂交猪72头(体重(18.44±1.34)kg),考察了含15%麦麸的生长猪饲粮中以磷酸氢钙形式添加0、0.09%、0.18%、0.27%、0.36%无机磷(IP)和在玉米-豆粕对照饲粮中添加0.26%IP对生产性能、干物质(DM)、钙(Ca)、总磷(TP)表观消化率的影响。结果表明:与对照组相比,15%麦麸饲粮中添加不同水平的IP对平均日增重(ADG)、平均日采食量(ADFI)、饲料转化率(F/G)均无显著影响(P>0.05);DM、Ca、TP表观消化率随IP添加水平的提高而逐渐下降。15%麦麸不加无机磷组生产性能与对照组比较差异不显著(P>0.05),但DM、Ca、TP表观消化率分别提高5%、54.9%、32.4%(P<0.01)。回归分析表明:15%麦麸饲粮添加无机磷0.1%,生长猪生产性能最高。以生产性能为衡量指标,生长猪饲粮含15%麦麸可减少0.16%的无机磷。含麦麸的植物性饲粮具有节约无机磷的作用。     

肉鸭常用植物性饲料原料有效磷评定及可加性研究

本文旨在用强饲-排宅法研究肉鸭植物性饲料原料有效磷的可加性.选择体重相近的21日龄樱桃符雄性肉鸭84只,随机分为7组,每组6个重复,每个重复2只鸭.分别强饲70 g玉米、豆粕、棉籽粕、菜籽粕和等比例混合的玉米-豆粕、玉米-豆粕-棉籽粕、玉米-豆粕-棉籽粕-菜籽粕混合饲粮,集粪袋法收集48 h排泄物,测定磷的生物学效价.结果显示,肉鸭对3种组合混合饲粮中,玉米-豆粕-棉籽粕组合的总磷表观利用率、总磷真利用率、表观有效磷和真有效磷的实测值与计算值差异显著(P＜0.05),玉米-豆粕和玉米-豆粕-棉籽粕-菜籽粕2种混合饲粮实测值与计算值差异不显著(P＞0.05).由此得出如下结论;1)饲料原料真有效磷的可加性优于表观有效磷的可加性;2)不同饲料原料可加性优劣因原料组合不同而存在一定的差异.     

不同方法测定肉鸭内源磷排泄量的比较研究

本研究通过比较无磷饲粮法、梯度回归法和差量法测定肉鸭内源磷排泄量的差异,旨在确立合理的肉鸭内源磷排泄量测定方法.选取21日龄雄性樱桃谷肉鸭150只,随机分成5个处理,每个处理设6个重复,每个重复5只鸭.采用无磷原料配制无磷纯合饲粮,以豆粕为唯一含磷原料配制总磷水平分别为0.20%、0.35%、0.51%和0.55%的低...     

植酸酶提高肉鸡生长性能和磷利用率的研究

本研究在不同类型和有效磷水平日粮中添加植酸酶对肉用仔鸡进行生长性能和磷利用效果评定，结果表明：①不同有效磷水平日粮加植酸酶（２００～４００Ｐｕ／ｋｇ）均明显提高体增重、饲料利用率，在玉米—糠麸—菜、豆粕日粮中加植酸酶的反应受日粮有效磷水平的影响，低磷日粮加植酸酶有较大的应答；②肉鸡生长性能的改善与磷、钙、锌利用增高相关，饲喂添加植酸酶日粮的肉鸡血清磷、胫骨灰分、磷、钙、锌含量提高，植酸磷、总磷、钙的表观利用率增加；③添加植酸酶，玉米—豆粕型日粮对肉鸡增重和饲料效率未见明显改善，而玉米—糠麸—棉、豆粕型日粮对肉鸡生长性能有提高趋势；④含较高植酸磷的肉鸡日粮中添加植酸酶可减少或不添加无机磷酸盐     

非淀粉多糖酶和植酸酶对肉仔鸡生长性能和养分利用性的影响

以 8 8 8只艾维因肉仔鸡为试验动物 ,研究添加非淀粉多糖酶 (40 0mg/kg)和植酸酶 (30 0mg/kg)对肉仔鸡的生长性能和养分利用性的影响。试验结果表明 :玉米 -菜粕 -豆粕日粮中添加非淀粉多糖酶 (减少 1.4 %AME)和植酸酶(减少 0 .0 8%非植酸磷 ) ,甚至再减少 0 .0 1%赖氨酸 ,都不会显著影响肉仔鸡 4 2日龄体重 (P >0 .0 5 ) ,但饲料转化率得到改善 ,死亡率降低。添加非淀粉多糖酶可提高AME和TME(P >0 .0 5 )和氮沉积量和氮表观消化率 (P >0 .0 5 )。非淀粉多糖酶对总磷的消化率没有显著影响 (P >0 .0 5 ) ,但同时添加非淀粉多糖酶和植酸酶 (减少 0 .0 8%非植酸磷 ) ,可显著提高总磷的表观消化率和真消化率分别为 16和 16 .1个百分点 (P <0 .0 5 )。     

The effect of microbial phytase on ileal phosphorus and amino acid digestibility in the broiler chicken

1. The study aimed to assess the effect of a commercially available microbial phytase on phytate phosphorus and total phosphorus content at the terminal ileum as well as true ileal amino acid digestibility. 2. Five diets, each containing a different plant-based feedstuff, were supplemented with microbial phytase and fed, along with a non-supplemented corresponding diet, to 28-d-old broiler chickens, Chromic oxide was used as an indigestible marker. Ileal contents were collected and analysed, along with the diets, for total phosphorus, phytate phosphorus and amino acids. 3. Endogenous phosphorus determined at the terminal ileum was 272 +/- 108 mg/kg food dry matter (mean +/- SE). Endogenous ileal amino acid flows ranged from 58 +/- 10 mg/kg food dry matter for methionine to 568 +/- 47 mg/kg food dry matter for glutamic acid. 4. Supplementation with microbial phytase resulted in a significantly greater phytate P disappearance from the terminal ileum for rice bran (17% units), but not for soyabean meal, maize, wheat or rapeseed meal. Similarly total phosphorus digestibility was significantly (P < 0.05) higher when microbial phytase was added to the rice-bran-based diet but not for any of the other feedstuffs. 5. Amino acid digestibility was significantly greater in the presence of microbial phytase for all the amino acids examined in wheat, for several of the amino acids each in maize and rapeseed meal and for one amino acid in rice bran and soyabean meal. The average increase in amino acid digestibility for those amino acids affected, was 13, 6, 10, 7 and 12% units for wheat, maize, rapeseed meal, rice bran and soyabean meal, respectively. 6. It appears that microbial phytase improves phosphorus digestibility and amino acid digestibility for certain plant-based feedstuffs.     

鹅和鸡4种常用饲料原料的代谢能比较

本试验旨在比较鹅和鸡常用饲料原料的代谢能差异.选用体重为(3.76±0.23)kg的成年扬州鹅(公)和体重为(2.57±0.17)kg的成年新扬州鸡(公)各10只,采用Sibbald真代谢能法测定玉米、豆粕、稻谷、麦麸4种常用饲料原料的代谢能值,内源能测定采用饥饿法.结果表明:玉米、豆粕的表观代谢能(AME)鹅与鸡差异不显著(P＞0.05),真代谢能(TME)鹅显著低于鸡(P＜0.05);而稻谷、麦麸的AME鹅显著高于鸡(P＜0.05),TME鹅与鸡差异不显著(P＞0.05).每小时内源能排出量,除强饲豆粕条件下鹅略高于鸡但差异不显著外(P＞0.05),强饲其他3种饲料条件下,鹅均显著高于鸡(P＜0.05).由此表明,鹅的饲料代谢能与鸡的并不完全相同,部分饲料的代谢能鹅和鸡之间存在显著差异,并且鹅的内源能排出量高于鸡.     

The influence of caecectomy on amino acid availability of three feedstuffs for ganders

1. Experiments were conducted to assess the influence of caecectomy on amino acid availability (AAA) of three feedstuffs for goose. 2. Nine caecectomised and 9 intact Yangzhou ganders, 24 weeks old, were used in these experiments. Fish meal, soybean meal and cottonseed meal were used as the sole source of protein. The endogenous amino acid (AA) losses were evaluated by a nitrogen (N)-free diet method. The influence of caecectomy on apparent amino acid availability (AAAA) in fish meal, soybean meal and cottonseed meal was assessed in experiment 1 and true amino acid availability (TAAA) of three protein diets was determined in experiment 2. 3. Results showed that, in the soybean meal and cottonseed meal, the AAAA and TAAA of most AA determined by the intact ganders were higher than in the caecectomised ganders; in the fish meal, the AAAA and TAAA of most AA determined by the intact ganders were lower than in the caecectomised ganders. 4. Results of the present study suggest that the effect of caecectomy on AAA in geese was dependent on the feedstuff assayed, and it was better to use caecectomised poultry for AAA assessment.     

二元线性回归法测定生长猪内源磷排泄量及麦麸和豆粕磷的真消化率

本研究采用二元线性回归法测定生长猪内源磷排泄量及麦麸和豆粕磷的真消化率.选用6头健康大白×长白阉公猪为试验动物,平均体重为(34.42±0.64)kg.采用6×6拉丁方设计,设6个总磷水平(0.12%、0.25%、0.28%、0.35%、0.47%和0.54%),日粮以豆粕、葡萄糖、玉米淀粉等为基础原料,麦麸和豆粕为磷来源.日粮中添加0.1%TiO2作为外源指示剂.试验分6个试验期,每期6 d,4 d适应期,2 d收粪期.结果表明,生长猪粪磷的排出量与日粮磷的摄入量呈线性关系(y=0.515 7x-0.0133,R2=0.97,P<0.01),回归法测得生长猪内源磷的排泄量为0.933 0g/kg,麦麸和豆粕磷的真消化率分别为48.07%和47.50%.分析粪磷来源发现,内源磷排泄量基本不变(P>0.05),而粪磷随日粮磷含量的增加而极显著增加(P<0.01).由结果可知,线性回归法可用于测定猪内源磷排泄量及麦麸和豆粕磷的真消化率.     

Pre-cecal phosphorus digestibility for corn,wheat, soybean meal,and corn gluten meal in growing Japanese quails from 28 to 32 d of age

The optimization of dietary phosphorus (P) depends on precise details of the P availability in feed ingredients to avoid excess or deficient P in a mixed diet. This study was carried out to measure the apparent ileal digestibility of P for corn, wheat, soybean meal, and corn gluten meal in growing Japanese quails from 28 to 32 d posthatch. A total of 400 quail chicks were randomly distributed across 5 treatments with 4 replicates and 20 birds in each floor pen. The P-free diet (PFD) was formulated based on cornstarch to measure the basal endogenous P losses (EPL). Digestibility coefficients were determined by ileal digesta sampling using TiO₂ as an indigestible marker. The EPL was estimated at 384 mg/kg DMI. The apparent ileal P digestibility (AIPD) for corn, soybean meal, wheat, and corn gluten meal were determined to be 0.38, 0.53, 0.38, and 0.78, respectively. The corresponding values for true ileal P digestibility (TIPD) were 0.48, 0.61, 0.50, and 0.83, respectively. The t-test analysis showed that the difference of AIPD and TIPD values for corn (P = 0.031) and wheat (P = 0.015) were statistically significant, however, no significant differences were observed for corn gluten meal (P = 0.318) and soybean meal (P = 0.104). In conclusion, the correction of AIPD coefficients for EPL in low-P ingredients such as corn and wheat may be much more important than that in high-P feedstuffs such as corn gluten meal and soybean meal in growing quails.     

Ileal amino-acid digestibility of wheat, autoclaved wheat and spaghetti by-products for broiler chicks

An experiment was conducted to determine true and apparent ileal amino‐acid digestibility of a native cultivar of wheat (Mahdavi), autoclaved wheat (120°C for 30 min) and spaghetti by‐products available in Iran. One hundred 21‐day‐old broiler chickens were fed a standard corn–soybean meal starter diet from day 0 to 28 post hatch. At 28 days 80 chicks were distributed according to possessing very nearly the same average bodyweight to 20 wire cages. The experimental units were allocated at random to five dietary treatments with four replicates per treatment. The basal diet contained corn and soybean meal as the major ingredients. Three test diets were formulated containing wheat, autoclaved wheat and spaghetti by‐products as the sole source of dietary protein and each test diet was combined with a basal diet 50:50 on a weight basis to form three assay diets. The apparent and true digestibility of amino acid in the test ingredients were estimated from those in the assay diets basal/test diet mixtures, using the difference method. The apparent and true amino‐acid digestibility of the test ingredients were significantly different (P < 0.01). Autoclaving of wheat increase its amino‐acid digestibility (P < 0.01). Among the test ingredients, the average ileal amino‐acid digestibility of spaghetti by‐products was higher than wheat and autoclaved wheat but it was lower than values for the basal diet (P < 0.01).     

Influence of Temperature on the Arginine and Methionine Requirements of Young Broiler Chicks

Two experiments were conducted with Ross × Ross broiler chicks in battery brooders from 7 to 21 d of age to determine the Arg and Met requirements of young broiler chicks at control (25°C) and warm (35°C) temperatures. In both experiments, 1-d-old broiler chicks were fed a corn and soybean meal based starter diet for 7 d. Six replications (2 replicates in each of 3 rooms per temperature) with 8 chicks each were used for each treatment. In experiment 1, the basal diet was based on corn (34.52%), whey (26.96%), corn gluten meal (16.53%), soybean meal (11.74%), and poultry fat (23% of CP and 3.20 kcal/g of ME_n). Six levels of Arg (0, 0.1, 0.2, 0.3, 0.4, and 0.5%), supplementing the basal diet containing 0.95% Arg, were the dietary treatments. A broken-line linear model was used to estimate chick Arg requirements. Based on body gain and feed conversion ratio (FCR) data, respectively, the Arg requirements of young Ross × Ross broiler chicks raised at 35°C were 1.15 ± 0.03% and 1.13 ± 0.02%, whereas those of chicks at 25°C were 1.26 ± 0.03% and 1.27 ± 0.02%. In experiment 2, the influences of temperature and dietary Arg on the Met requirements of young broiler chicks were investigated. The basal diet was based on corn (53.45%), soybean meal (37.72%), and poultry fat (23% of CP and 3.20 kcal/g of ME). Experiment 2 had a 6 × 2 factorial arrangement, with the basal diet (0.35% Met and 1.52% Arg) supplemented with 6 levels of dietary Met (0, 0.05, 0.1, 0.15, 0.2, or 0.3%) and 2 levels of dietary Arg (0 and 1.0%). When chicks were fed a corn-soybean meal basal diet containing 1.52% Arg, the Met requirements of young Ross × Ross broiler chicks raised at 35°C were 0.43 ± 0.02% and 0.43 ± 0.03%, whereas those of chicks at 25°C was 0.43 ± 0.01% and 0.48 ± 0.03%, based on body gain and FCR data, respectively. When Arg levels were increased to 2.52%, the Met requirement of young Ross × Ross broiler chicks was greater at both temperatures (P < 0.05). The requirements of chicks raised at 35°C were 0.50 ± 0.02% and 0.49 ± 0.02% and at 25°C were 0.59 ± 0.03% and 0.57 ± 0.02%, based on body gain and FCR data, respectively. Temperature and amino acid balance may both affect the amino acid requirements of broilers.     

2015年山东省肉鸡饲料原料中重金属污染情况调查及风险评估

本试验旨在调查2015年山东省肉鸡饲料原料中砷、铅、镉、铬和汞元素的污染情况,评估饲料原料的污染风险。试验收集烟台市莱阳、威海市文登、青岛市莱西、潍坊市诸城、日照市莒县、临沂市沂水、德州市夏津等地不同饲料生产厂家使用的8种饲料原料,包括玉米、豆粕、麸皮、花生粕、棉籽粕、玉米蛋白粉、干酒糟及其可溶物( DDGS)和微量元素预混料,应用电感耦合等离子体原子发射光谱法( ICP-AES)检测镉、铅和铬元素的含量,应用原子荧光光谱法( AFS)检测砷和汞元素的含量,计算检出率、平均含量、超标率、最高含量与平均含量比值( HC/AC)和离散系数。结果表明：饲料原料中砷、铅、镉、铬和汞元素的检出率分别为32.29%、7.29%、12.50%、100.00%和100.00%;阳性样品中平均含量分别为0.21、1.27、2.12、3.48和0.02 mg/kg,超标率分别为0.00、1.04%、1.19%、54.76%和9.52%;微量元素预混料中砷、铅和镉元素,棉籽粕中铬元素及花生粕中汞元素的HC/AC最大,微量元素预混料中镉元素、花生粕中汞元素、豆粕中砷元素及棉籽粕中铅和铬元素离散系数最大。综上所述,肉鸡饲料原料中铬和汞元素污染严重;微量元素预混料中砷、镉、铬和铅元素、棉籽粕中铬和铅元素、花生粕和豆粕中汞元素易出现严重污染,因此建议制定预混料和饼粕类饲料中多种重金属元素的限量标准。     

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。     

Feed preference in pigs: effect of selected protein, fat, and fiber sources at different inclusion rates

Three double-choice feeding experiments were conducted to study the effect of different feedstuffs on feed preference in pigs. Fifteen protein sources, 6 fat sources, and 3 fiber sources were evaluated in Exp. 1, 2, and 3, respectively. Pigs were offered a series of double choices between a common reference diet and the diet with the ingredient under evaluation. The reference diet contained a soybean meal product with 56% CP (SBM-56), sunflower oil, and wheat bran, which were considered as the feedstuffs of reference for the protein, fat, and fiber sources, respectively. Preference, expressed as percentage of the tested diet to total feed intake, was affected by feedstuff nature and by its inclusion rate. In Exp. 1, feeds with fish meal at 50 and 100 g·kg?1, dried porcine hydrolyzed protein at 50 g·kg?1, and lupine, soybean meal with 44% CP, and dried skim milk at 100 g·kg?1 were preferred (P < 0.05) to the reference feed with SBM-56. On the contrary, relative to SBM-56, an avoidance (preference less than 50%) was observed for potato protein at all inclusion rates tested, rapeseed meal and acid milk whey at 100 and 200 g·kg?1, and dried porcine hydrolyzed protein, soybean protein concentrate, wheat gluten, and sunflower meal at 200 g·kg(-1). The storage of dried skim milk, soybean protein concentrate, and potato protein for 10 mo resulted in a reduction (P < 0.001) of their preference values. In Exp. 2, the feed with palm oil (at 30 g·kg?1) was preferred (P < 0.05), whereas feeds with linseed oil (at 30 and 100 g·kg?1) and soybean oil (at 100 g·kg?1) were avoided (P < 0.05) when contrasted with the reference feed with sunflower oil. Finally, in Exp. 3 diets with dehydrated alfalfa and sugar beet pulp at 130 g·kg?1 had a reduced (P < 0.05) preference compared with the reference diet with wheat bran. It is concluded that feedstuff nature, inclusion rate, and freshness affect feed preference in pigs. Feedstuff preferences should be taken into account during diet formulation, particularly at critical stages such as immediately after weaning.