酵母锌和硫酸锌对肉仔鸡微量元素沉积的影响

将140只1日龄艾维茵商品代肉仔鸡,随机分为7组。试验采用2×3因子设计,另设一个对照组,共7个处理,每个处理4个重复,每个重复5只鸡。在基础日粮中分别添加40、80和120mg/kgZn,分别来自酵母锌和硫酸锌。饲喂21d,取肝脏、肾脏、胫骨、胸肌,测定铁、铜、锌、锰浓度。试验结果表明:酵母锌组的胫骨锌(P<0.05)、肝脏铜(P<0.05)和肝脏铁浓度(P<0.01)明显高于硫酸锌组,说明酵母锌能明显提高胫骨锌浓度,对铜、铁吸收的抑制作用小于硫酸锌。     

酪蛋白磷酸肽(CPP)对肉仔鸡矿物质代谢的影响

采用2×3二因素随机试验设计,钙水平分别为0.5%和1.0%,酪蛋白磷酸肽(CPP)水平分别为0%、0.1%和0.5%.选用144只1日龄AA肉仔鸡,公母各半,随机分为6组,每组4个重复,每个重复6只鸡.试验期为4周.试验结果表明:①CPP对肉仔鸡日增重、日耗料量和料肉比影响不显著(P＞0.05).②CPP对肉仔鸡血液红细胞数、血红蛋白、红细胞压积、钙、磷、铁、铜、锌和锰含量的影响不显著(P＞0.05).③CPP能显著提高肉仔鸡胫骨中钙和铁的含量(P＜0.01),0.5%CPP显著提高胫骨灰分(P＜0.01)以及铜、锌和锰含量(P＜0.05),胫骨参数及磷含量差异不显著(P＞0.05).④CPP显著提高肝脏铁、锰(P＜0.05)以及锌含量(P＜0.01),但肝脏铜浓度差异不显著(P＞0.05).     

大蒜素对肉仔鸡脂肪代谢及相关基因表达的影响

探讨大蒜素对肉仔鸡脂类代谢及相关基因表达的影响,为揭示大蒜素调节动物脂肪沉积的机理作依据。试验选取体重相近、体格健壮的1日龄AA肉仔鸡(公)96只,随机分成4组,每组设4个重复,每个重复6只鸡。试验期为42d。在各组基础饲料中分别添加0、200、400、600mg/kg的大蒜素。结果表明,添加400和600mg/kg大蒜素的处理组与对照组比较,肉仔鸡腹脂率和肝脂率显著降低(P0.05);而添加200、400及600mg/kg大蒜素的处理组与对照组比,皮下脂肪厚度和肌间脂肪厚度没有显著的差异(P0.05),但有下降的趋势。400mg/kg组和600mg/kg组的甘油三酯、总胆固醇及低密度脂蛋白的含量显著下降(P0.05);而高密度脂蛋白水平则呈现出显著的提高(P0.05)。各浓度添加大蒜素组的游离脂肪酸的水平与对照组相比而言,有降低的趋势,但差异不显著(P0.05)。添加400mg/kg或600mg/kg大蒜素可显著降低AA肉仔鸡肝脏中的乙酰辅酶A羧化酶、脂肪酸合成酶的mRNA表达水平(P0.05);添加600mg/kg大蒜素组的肉仔鸡肝脏脂蛋白脂酶mRNA水平显著上调(P0.05)。添加600mg/kg大蒜素的肉仔鸡腹脂中乙酰辅酶A羧化酶mRNA表达水平显著低于对照组(P0.05),脂蛋白脂酶mRNA水平则显著上升(P0.05)。大蒜素对肉仔鸡腹脂脂肪酸合成酶mRNA水平无显著影响。     

复合吸附剂对饲料中有毒重金属的脱毒研究

选用1日龄健康的艾维茵肉鸡120只,随机分成4个组,每个组6个重复,每个重复5只鸡,分别喂以基础日粮(对照1)、重金属污染日粮(基础日粮+10 mg/kg铅+5 mg/kg镉+0.3 mg/kg汞(对照2)、重金属污染日粮+0.05%复合吸附剂(处理1)和重金属污染日粮+0.1%复合吸附剂(处理2),试验期为42天。结果表明:在肉鸡日粮中添加10 mg/kg铅+5 mg/kg镉+0.3 mg/kg汞,对肉仔鸡生产性能无明显影响,但造成血清和肝脏中超氧化无物歧化酶和谷光甘肽过氧化物酶活性降低,血清丙二醛含量显著升高,腿肌、胸肌、肝、肾中铅、镉、汞残留量显著增加(P0.05),并可影响微量元素铜、铁、锌在不同组织中的正常分布;在受重金属元素污染的饲料中添加由葡甘露聚糖与膨润土(4∶1)组成的复合吸附剂,可显著降低组织中有毒重金属元素含量,并使铜、铁、锌在组织中的异常分布得到恢复。     

半胱胺对肉仔鸡部分生理生化指标的影响

试验选择144只1日龄的AA肉仔鸡随机分为4个组(Ⅰ、Ⅱ、Ⅲ、Ⅳ组);预饲1周后分别在基础日粮中添加0、50、100、150 mg/kg的半胱胺,于添加半胱胺后第2、4和6周龄时颈静脉采血,测定血液中红细胞数、白细胞数、血红蛋白含量,血清中葡萄糖、钙、磷、钾、镁、铜浓度以及血清中碱性磷酸酶(ALP)、丙氨酸氨基转移酶(ALT)和门冬氨酸氨基转移酶(AST)活性,研究半胱胺对肉仔鸡部分生理生化指标的影响。结果表明:饲料中添加适量的半胱胺(50~100 mg/kg)能提高血液中红细胞数、白细胞数、血红蛋白含量和血清中钾、钙浓度,降低血清中镁、铜浓度,对肉仔鸡血清中磷、血糖浓度影响不明显。添加50~100 mg/kg的半胱胺对ALT、AST活性影响不明显;而ALP活性随着半胱胺添加量的增加而升高。说明肉仔鸡饲料中半胱胺的添加量以50~100 mg/kg为宜。     

植物甾醇对肉鸡血清胆固醇、蛋白质水平和抗氧化酶活性的影响

目的:研究植物甾醇对肉仔鸡生产性能、血液胆固醇、蛋白质水平和抗氧化酶活性的影响。方法:试验设6组,日粮中分别添加0、5、10、20、40和80mg/kg的植物甾醇,测定肉仔鸡生产性能及血液生化指标。结果:与对照组相比:植物甾醇可提高肉仔鸡的生产性能;20mg/kg植物甾醇添加组能显著降低肉仔鸡血清总胆固醇(TC)水平(P<0.05),极显著降低血清低密度脂蛋白胆固醇(LDL-C)水平(P<0.01),10、40和80mg/kg组均能显著降低LDL-C水平(P<0.05);40mg/kg组能显著提高血清白蛋白水平(P<0.05);80mg/kg组能显著提高肉鸡前期和后期血清总超氧化物歧化酶(T-SOD)活性(P<0.05)。结论:40mg/kg为植物甾醇在肉仔鸡日粮中的适宜添加水平。     

饲喂银杏叶超微粉对鸡蛋胆固醇含量的影响

实验旨在研究银杏叶超微粉对鸡蛋胆固醇含量的影响。选择健康55周龄的罗曼白商品蛋鸡192羽,随机分为对照组和实验组共4组,每组3个重复,每个重复16羽,对照组饲喂基础日粮,实验组在基础日粮中分别添加0.60%、0.80%、1.00%的银杏叶超微粉,预试期7d,正试期28d。结果表明:在第7、28d时,添加银杏叶超微粉对蛋重和蛋黄重、蛋黄相对重影响不显著(p>0.05);第14d时,0.60%、0.80%银杏叶超微粉添加组蛋黄重较对照组差异显著(p<0.05),蛋重和蛋黄相对重差异不显著(p>0.05);第21d时,0.80%、1.00%银杏叶超微粉添加组蛋黄重和蛋黄相对重较对照组差异显著(p<0.05),蛋重差异不显著(p>0.05)。整个实验期,蛋黄胆固醇含量和鸡蛋胆固醇含量较对照组差异显著(p<0.05),在第21d时,0.80%银杏叶超微粉添加组呈现极显著差异(p<0.01),实验至28d时,银杏叶超微粉对鸡蛋胆固醇含量的影响趋于平稳。本实验表明银杏叶超微粉对降低鸡蛋胆固醇具有一定的促进作用,且以0.80%添加量为效果最佳。     

壳聚糖对肉仔鸡生长性能及血清生化指标的影响

探讨在基础日粮中添加不同水平的壳聚糖替代抗生素对内仔鸡生长性能及脂类代谢的影响.结果表明:100 mg/kg壳聚糖组肉仔鸡平均日增重提高显著,料肉比降低显著;在血清生化指标方面,100 mg/kg壳聚糖组相比对照组降低了血清中总胆固醇(TC)、总甘油三酯(TG)含量(P<0.05),提高了总蛋白(TP)、类胰岛素生长因子(IGF-1)和生长激素(GH)含量(P<0.05),而对葡萄糖和尿酸含量无影响(P>0.05).壳聚糖的适宜添加水平为100 mg/kg.     

酵母硒对肉鸡组织硒含量及抗氧化能力的影响

试验选择108只1日龄健康AA肉仔鸡(公母混合),随机分为3组,每组3个重复,每重复12只鸡,对照组饲喂基础日粮,试验组A在对照组日粮基础上添加0.3mg/kg硒(亚硒酸钠),试验组B在对照组日粮基础上添加0.3mg/kg硒(酵母硒),饲养35d。通过检测试验鸡组织中硒含量和超氧化物酶活性及丙二醛含量,来研究酵母硒对肉鸡组织硒含量和抗氧化能力的影响。结果表明:酵母硒组鸡群的肌肉组织中硒含量显著高于对照组;与对照组相比,酵母硒和亚硒酸钠均可显著提高鸡群血液和组织中超氧化物歧化酶活性,显著降低丙二醛含量。     

大蒜素对AA肉仔鸡生长性能的影响

选择健康1日龄AA肉仔鸡1 080羽随机分成6个组,在各组基础日粮中分别添加0、100、200、300、400和500 mg/kg的大蒜素,饲喂7周。结果表明,日粮中添加大蒜素对不同生长阶段肉仔鸡的存活率、平均日增重及料肉比均有不同程度的改善作用,其中300 mg/kg的大蒜素对肉仔鸡生长性能的影响达到了显著(P<0.05)或极显著(P<0.01)水平。故本试验得出日粮中添加300 mg/kg的大蒜素是改善肉仔鸡生长性能的最适添加量。     

氨基酸微量元素螯合物替代无机微量元素对肉鸡饲养效果的影响

研究氨基酸微量元素螯合物替代饲粮中无机微量元素对肉鸡生产性能、饲粮养分代谢率和粪中微量元素含量的影响。1组为对照组饲喂基础饲粮,其Fe、Cu、Mn、Zn分别由硫酸亚铁、硫酸铜、硫酸锰和氧化锌提供,添加水平分别为Fe 100 mg/kg、Cu 20 mg/kg、Mn 120 mg/kg和Zn 120 mg/kg;2、3、4和5组分别用12.5%、25.0%、37.5%和50.0%的蛋氨酸螯合铁、铜、锰、锌替代基础饲粮各相应无机微量元素的25%、50%、75%和100%。63 d的试验结果表明:与对照组比较,用不同水平蛋氨酸螯合物(铁、铜、锌、锰)替代相应无机盐可一定程度提高肉鸡的生产性能,改善饲粮养分利用率,提高养殖效益,降低粪中微量元素的排泄量,尤以37.5%的蛋氨酸微量元素螯合物替代饲粮中75%的相应无机微量元素的效果良好。     

Short communication: Effects of supplementing diets of Holsteins with copper,zinc, and manganese on blood neutrophil function

The effects of supplementing diets with sulfate or glycinate Cu, Zn, and Mn on blood neutrophil function were examined in 27 late-lactation Holstein cows having a mean (± standard deviation) days in milk at time of neutrophil assays of 216 ± 31 d. Cows were assigned to 9 blocks of 3 and were grouped by parity, milk production, and days in milk. Cows within each block were randomly assigned to 1 of 3 treatments: (1) control diet devoid of supplemental Cu, Zn, and Mn; (2) diet supplemented with Cu, Zn, and Mn via sulfates; and (3) diet supplemented with Cu, Zn, and Mn via glycinate form. All cows were initially fed a control total mixed ration with basal mineral concentrations of 8 mg/kg of Cu, 35 mg/kg of Zn, and 35 mg/kg of Mn for 30 d. During the treatment period, cows fed diets with mineral supplementation via sulfates or glycinate forms had target total dry matter dietary concentrations of 18 mg/kg of Cu, 60 mg/kg of Zn, and 60 mg/kg of Mn for 30 d. Control cows were fed the control diet devoid of supplemental minerals for an additional 30 d. In vitro neutrophil functions were measured after 30 d on experimental or control diets. Percentage of neutrophils phagocytizing, intracellular kill, and phagocytic index did not differ among treatments. Serum concentrations of Cu, Zn, and Mn were also not affected by dietary treatment after 30 d. Results from this study demonstrated that dietary Cu, Zn, and Mn supplemented either as sulfates or glycinate form for 30 d had no effect on either in vitro blood neutrophil function or serum concentrations of Cu, Zn, and Mn in late-lactation Holstein cows.     

Effect of zinc source and dietary level on zinc metabolism in Holstein calves

Forty-eight Holstein male calves were stratified by origin and body weight and randomly assigned to one of 4 treatment groups. Dietary treatments were administered in 2 phases. In phase 1, treatment groups received the basal diet with no supplemental Zn (control), basal diet plus 20 mg of Zn/kg of DM as ZnSO4 or Zn proteinate (ZnProt), or basal diet plus 20 mg of Zn/kg of DM with 50% of the Zn supplied from each source (ZnM) for 98 d. In phase 2, calves continued to receive the same Zn source fed in phase 1; however, half of the calves in each treatment group were randomly selected to receive 500 mg of Zn/kg of DM (HiZnSO4, HiZnProt, HiZnM) for 14 d. Gain, feed intake, and feed efficiency of calves were not affected by treatment in either phase of the experiment. Treatment had no affect on plasma Zn concentration or alkaline phosphatase activity in phase 1, but liver Zn concentration was greater in calves fed ZnSO4 than those fed ZnProt. In phase 2, plasma Zn was greater in calves fed HiZnProt and HiZnM than in those fed HiZnSO4. Liver Zn was greater in calves fed HiZnProt than in those fed HiZnSO4. Duodenal Zn concentrations were greater in calves supplemented with HiZnProt and HiZnM than those supplemented with HiZnSO4. Liver metallothionein was greater in calves that received 500 mg of Zn/kg than in calves that received 20 mg of Zn/ kg, but was not affected by Zn source. Calves fed HiZnProt and HiZnM had greater kidney Zn concentrations than those fed HiZnSO4. Heart, spleen, testicular, and bone Zn concentrations were not affected by Zn source. Hoof wall samples contained nearly 3-fold greater Zn concentrations than hoof sole. Calves fed ZnSO4 had greater Zn concentration in hoof wall samples than those fed ZnM. Hoof sole Zn concentration was not affected by Zn source or concentration. Plasma and tissue Zn concentrations at harvest were generally similar in calves supplemented with 20 mg of Zn/kg from ZnSO4 or ZnProt. However, when supplemented at 500 mg of Zn/kg, ZnProt was absorbed to a greater extent than ZnSO4, based on higher plasma, liver, duodenal, and kidney Zn concentrations.     

Oxidative and lipolytic changes during ripening of Iberian hams as affected by feeding regime: extensive feeding and alpha-tocopheryl acetate supplementation

The effect of pig feeding in an extensive system based on acorn and pasture or in confinement with a control diet containing 5 mg α-tocopheryl acetate kg(-1) of feed and a 100 mg α-tocopheryl acetate kg(-1) enriched diet on evolution of lipid changes throughout ripening of dry-cured hams was investigated. Feeding regime significantly affected TBA-RS, peroxide value and hexanal content of Biceps femoris and Semimembranosus muscles. Muscles from pigs fed supplemented diet with α-tocopherol or fed extensively on acorn and grass showed significant lower (p<0.05) TBA-RS and peroxide value than ham muscles from pigs fed the basal diet at 210 days of processing. Both feedings reduced significantly (p<0.05) hexanal content at day 210 and day 700. Muscle slices from pigs fed on acorn showed significant higher scores (p<0.05) in aroma and flavour intensity, cured flavour and numerically lower rancid scores than those from control diet hams. ?     

Potential of Cultivated Ganoderma lucidum Mushrooms for the Production of Supplements Enriched with Essential Elements

Ganoderma lucidum is an important medicinal mushroom species and there is continuous interest in its bioactive properties. This study evaluated whether it may additionally serve as a nutritional supplement for the trace elements: selenium (Se), copper (Cu), and zinc (Zn). Mushrooms were cultivated on substrates enriched with 0.1 to 0.8 mM of inorganic Se alone or in combination with Zn and/or Cu. Supplementation increased accumulation of the elements in fruiting bodies regardless of the applied cultivation model. G. lucidum demonstrated the ability to accumulate significant amounts of organic Se, maximally amounting to (i) over 44 mg/kg when the substrate was supplemented only with Se, (ii) over 20 mg/kg in the Se+Cu model, (iii) over 25 mg/kg in the Se+Zn model, and (iv) 15 mg/kg in the Se+Cu+Zn model. The accumulation of Cu and Zn steadily increased with their initial substrate concentrations. Maximum concentrations found after supplementation with 0.8 mM amounted to over 55 mg/kg (Se+Zn) and 52 mg/kg (Se+Cu+Zn) of Zn, and 29 mg/kg (Se+Cu) and over 31 mg/kg (Se+Cu+Zn) of Cu. The greater the supplemented concentration and number of supplemented elements, the lower the biomass of G. lucidum fruiting bodies. Nevertheless, it still remained high when the substrate was supplemented up to 0.4 mM with each element. These results highlight that G. lucidum can easily incorporate elements from the substrate and that, when biofortified, its dried fruiting bodies may serve as a nutritional source of these essential elements.     

日粮不同氟水平对生长猪微量元素沉积的影响

96头杜长大三元杂交猪，随机分为4组，第1组为对照组，饲喂基础日粮（含氟量37．39mg／kg），第2、3和4组分别饲喂含氟（以NaF形式添加）量为100，150，200mg／kg的日粮，研究日粮中不同氟水平对猪生长性能以及不同组织器官铁、铜、锌和锰沉积的影响。实验结果表明，第3、4组生长猪日增重与对照组相比分别降低了6．25％（P〈0．05）和8．22％（P〈0．05），料重比分别升高了7．37％（P〈0．05）和8．07％（P〈0．05）。而第2组猪的生长性能与对照组相比均无显著差异（P〉0．05）。另一方面，实验结果表明第3、4组氟的添加与对照组相比除显著增加了生长猪肾锌的沉积外（P〈0．05），均显著降低了大多数组织器官铁、铜、锌和锰的沉积（P〈0．05）。而第2组氟的添加量对于各微量元素在组织器官中的沉积与对照组相比均无显著差异（P〉0．05）。     

Effects of dietary high-oleic acid sunflower oil, copper and vitamin E levels on the fatty acid composition and the quality of dry cured Parma ham

The effects of seven isoenergetic dietary treatments: (1) no sunflower oil, 35 mg/kg Cu, without α-tocopheryl-acetate added; (2) to (7) 6% high oleic acid sunflower oil (HOSO), 35 or 175 mg/kg Cu crossed with a 0, 100 or 200 mg/kg α-tocopherol addition, were tested on quality characteristics of dry cured Parma hams from a total 84 Large White gilts. No statistically significant effect was detected on parameters of early evaluation of seasoning loss of hams. The seasoning loss and intramuscular fat content of seasoned hams averaged 28.1 and 3.3%, respectively, with no effect of the diet composition. The CIE L*a*b* colour values taken on the surface of the lean from Parma ham were not affected by dietary oil inclusion, nor by copper levels and by α-tocopherol addition in the feed mixture, except for the 'a' value that increased in HOSO groups (P<0.01) and in groups with α-tocopherol addition (P<0.01). The TBARS values in lean were reduced by the inclusion of HOSO (P<0.05) and α-tocopherol supplementation (P<0.10). Compared to the no oil group, the Parma hams in the HOSO groups showed a higher oleic acid content in the covering fat, but not different in neutral and polar fractions from semimenbranosus muscle. The oil inclusion reduced the saturated fatty acid content in subcutaneous fat and neutral lipids fraction from muscle to 30-34% No effect of α-tocopherol and copper levels were observed on fatty acids profiles. From the subjects fed the HOSO diet softer Parma hams were produced than those fed the control diet (χ(2)<0.05), while α-tocopherol and Cu levels did not influence the sensorial evaluation of hams. The inclusion of an oleic acid rich source in heavy pig diet brought about an improved nutritional value, but also the possible need of a prolonged ageing time to achieve an ideal firmness of Parma ham. Dietary α-tocopherol supplementation improved the red colour slightly and the lipid stability in Parma ham, while the supplementation of Cu in the diet had no influence on the tested parameters.     

鼠李糖脂对肉鸡腿肌肉品质、常规化学成分和抗氧化功能的影响

本试验旨在研究日粮中添加鼠李糖脂（Rhamnolipid）对肉鸡腿肌肉品质、常规化学成分和抗氧化功能的影响。选取1日龄爱拔益加（AA）公肉仔鸡600只,随机分为5组,每组8个重复,每个重复15只,空白对照组饲喂基础饲粮,抗生素组饲喂基础饲粮中添加75 mg/kg金霉素,试验组饲喂基础饲粮中分别添加250、500、1000 mg/kg鼠李糖脂的试验饲粮,试验为期42 d。与空白对照组相比,日粮中添加250、500、1 000 mg/kg鼠李糖脂和抗生素提高了肉鸡腿肌重和腿肌GPx活性,增加了腿肌24 h的pH值,降低了腿肌24 h和48 h滴水损失和蒸煮损失,减少了腿肌MDA含量,上调了腿肌SOD1和GPx的基因表达水平（P＜0.05）;此外,日粮中添加250、500、1 000 mg/kg鼠李糖脂降低了肉鸡腿肌24 h亮度值（P＜0.05）;日粮中添加500、1 000 mg/kg鼠李糖脂提高了肉鸡腿肌45 min的pH值和粗脂肪含量,增加了腿肌T-SOD活性,上调了腿肌Nrf2和HO-1的基因表达水平（P＜0.05）;日粮中添加1 000 mg/kg鼠李糖脂上调了肉鸡腿肌SOD2的基因表达水平（P＜0.05）。鼠李糖脂组和抗生素组肉鸡腿肌重和腿肌肉品质、常规化学成分、抗氧化酶活性和抗氧化相关基因表达水平均无显著差异（P＞0.05）。综上所述,鼠李糖脂可作为抗生素替代品添加于肉鸡饲料中,提高肉鸡腿肌重,改善腿肌肉品质,增加腿肌粗脂肪含量,提高腿肌Nrf2信号通路相关抗氧化基因表达水平,提高腿肌抗氧化能力。     

Effect of source of trace minerals in either forage- or by-product–based diets fed to dairy cows: 2. Apparent absorption and retention of minerals

Eighteen multiparous cows were used in a split-plot replicated Latin square with two 28-d periods to evaluate the effects of source of supplemental Cu, Zn, and Mn (sulfates or hydroxy) on apparent absorption of minerals when fed in either a forage- or by-product–based diet. The by-product diets were formulated to have greater concentrations of NDF and lesser concentrations of starch, and specific ingredients were chosen because they were good sources of soluble fiber and β-glucans, which bind trace minerals in nonruminants. We hypothesized that hydroxy trace minerals would interact less with digesta and have greater apparent absorption compared with sulfate minerals, and the difference in apparent absorption would be greater for the by-product diet compared with the forage-based diet. During the 56-d experiment, cows remained on the same fiber treatment but source of supplemental trace mineral was different for each 28-d period; thus, all cows were exposed to both mineral treatments. During each period cows were fed no supplemental Cu, Zn, or Mn for 16 d, followed by 12 d of feeding supplemental minerals from either sulfate or hydroxy sources. Supplemental minerals for each of the mineral sources fed provided approximately 10, 35, and 32 mg/kg of supplemental Cu, Zn, and Mn, respectively, for both fiber treatments. Total Cu, Zn, and Mn dietary concentrations, respectively, were approximately 19, 65, and 70 mg/kg for the forage diets and 21, 85, and 79 for the by-product diets. Treatment had no effect on dry matter intake (24.2 kg/d) or milk production (34.9 kg/d). Cows consuming the by-product diets had greater Zn (1,863 vs. 1,453 mg/d) and Mn (1,790 vs. 1,588 mg/d) intake compared with cows fed forage diets, but apparent Zn absorption was similar between treatments. Manganese apparent absorption was greater for the by-product diets compared with the forage diets (16 vs. 11%). A fiber by mineral interaction was observed for Cu apparent absorption, as cows fed hydroxy minerals with forage diets had greater apparent absorption compared with cows fed sulfate minerals; however, the opposite was observed with the by-product diets. Source of supplemental trace minerals and type of fiber in diets affected availability of Cu and Mn and should be considered in ration formulation.