Digestibility, apparent mineral absorption, and voluntary intake by horses fed alfalfa, tall fescue, and caucasian bluestem

Alfalfa (Medicago sativa L.), low-endophyte (< 5%) tall fescue (Festuca arundinacea Schreb.), and caucasian bluestem (Bothriochloa caucasica [Trin.] C.E. Hubbard) were fed as chopped hay to six Arabian geldings (BW 441 kg; SE 2) in intake and digestibility experiments to determine nutritional value for horses at maintenance. Each experimental design was a replicated Latin square. Alfalfa was higher in DM and CP digestibility, IVDMD, apparent absorption of Ca, K, and S, and voluntary intake than the grasses (P < .05). Caucasian bluestem was higher in Zn but was lower in CP, TNC, Mg, P, K, S, and Cu concentrations than tall fescue. Crude protein digestibility and apparent absorption of Mg, K, and S were higher (P < .05) for tall fescue than for caucasian bluestem. Geldings fed alfalfa for ad libitum intake had higher serum concentrations of vitamin A, blood urea nitrogen, P, S, and Cu than geldings fed grass hays. Serum Zn was higher (P < .05), whole blood Se tended to be higher (P < .06), and BUN was lower (P < .05) in geldings fed caucasian bluestem than in those fed tall fescue. All forages met requirements for CP, Ca, Mg, K, and Fe when fed for ad libitum intake but were deficient in Cu for horses at maintenance. Caucasian bluestem was borderline in CP and was deficient in P but was the only forage that met the Zn requirement for the horses. Based on these results, caucasian bluestem could be a useful hay for horses but may require supplementation of CP and P.     

长期低剂量喂饮稀土Y对小鼠全血中微量元素含量及比值的影响

通过在饮水中加入稀土钇 (0 ,2 3.2 5 m g/ L ,2 32 5 .0 0 mg/ L )使小白鼠长期摄入稀土 ,7个月后用 ICP-MS以及原子荧光法测定 F1子代小鼠全血中微量元素 Ca、Mg、Cu、Zn、Fe、Se等的含量 ,并计算其比值。结果显示 ,F1子代小鼠全血中 Se含量与对照相比显著增加 (低浓度组 P<0 .0 1,高浓度组 P<0 .0 5 ) ;高浓度组小鼠全血中Ca/ Fe、Ca/ Fe比值发生显著变化 (P<0 .0 1)。提示稀土钇的长期摄入可影响小鼠体内某些微量元素之间的平衡 ,这种平衡的变化可能引致机体某些生理状态的变化。     

A multi-element isotopic tracer assessment of true fractional absorption of minerals from formula with additives of calcium, phosphorus, zinc, copper and iron in young piglets

True fractional absorption of minerals was measured to determine the bioavailability of Zn, Fe, Mn and Se from liquid formulas fortified with stepwise additions of Ca and P (as Ca glycerophosphate and carbonate, Ca*P), and Zn, Cu and Fe (as sulfate salts). Growth, deposition of tracers in organs and bone mineral content of femurs as assessed by single photon absorptiometry were measured. Four-day-old piglets (n = 36) were randomly assigned to groups fed a basal diet or additions of Ca*P (Ca = 25, P = 18 g/kg dry diet), Ca*P+Zn (Zn = 0.04 g/kg), Ca*P+Zn+Cu (Cu = 0.007 g/kg) or Ca*P+Zn+Cu+Fe (Fe = 0.008 g/kg). Oral and intravenous administration of extrinsic isotopes of 59Fe, 54Mn, 65Zn, 75Se and 47Ca was followed by fecal monitoring for 15 d and true absorption calculated after accounting for endogenous excretion. Addition of Ca*P+Zn reduced Zn absorption (P < 0.05) and Ca*P+Zn+Cu reduced Fe absorption (P < 0.01), but Mn and Se absorptions were not altered. Uptake of only Zn tracer into heart was significantly different (P < 0.05) among diet groups. Weight gain and linear growth were similar in all groups. Addition of Ca*P produced higher bone mineral density, but its effect on Zn absorption warrants further investigation.     

Fatty acid profile and physical properties of milk fat from cows fed calcium salts of fatty acids with varying unsaturation

Holstein cows (n = 24) averaging 42 d in milk were used in a randomized complete block design during a 4-wk trial. A control total mixed ration (TMR) was compared with TMR supplemented with Ca salts of fatty acids from canola oil, soybean oil, or linseed oil. The three vegetable oils were progressively more unsaturated; the dominant fatty acids were, respectively, cis-delta-9-C18:1, C18:2, and C18:3. Apparent total tract digestibility of dry matter, crude protein, ether extract, and neutral detergent fiber was higher for rations containing Ca salts than for the control ration. Milk yield increased linearly as the unsaturation of the dominant fatty acid in the Ca salts increased. Milk fat percentage was reduced when Ca salts were added to the rations. The addition of Ca salts to the ration decreased the proportions of saturated fatty acids that contained C6 to C16 and increased the proportions of C18:0, cis-delta-C18:1, and trans-delta-11-C18:1 in milk fat. Proportions of C18:2 and C18:3 increased linearly, and cis-delta-9-C18:1 decreased linearly, as the unsaturation of the dominant fatty acid in the Ca salts increased. The proportion of fat that was liquid at 5 degrees C was higher for butter from cows fed diets containing Ca salts, but the proportion of liquid fat at 20 degrees C was not affected. Calcium salts of unsaturated fatty acids added to the diets of dairy cows improved the thermal properties of milk fat.     

用P204和P507脱除含钴废料中的杂质生产高纯度氯化钴

采用硫酸溶解预先焙烧的钐钴粉 ,化学中和法除稀土、铁和钙镁后用P2 0 4萃取铜、锰、锌等杂质 ,再用P5 0 7萃取分离镍和钴 ,制得的氯化钴溶液用来制备高纯氯化钴。钴回收率大于 90 %。     

Effect of zinc deficiency and varying zinc supplements on resorption and retention in dairy cows

5 lactating cows were used in a trial to investigate the process of Zn absorption and Zn retention under conditions of Zn deficiency and variations in Zn supplementation. The apparent Zn absorption was found to be markedly increased if the animals were fed a Zn deficient semisynthetic diet containing 6 mg Zn per kg of dry matter during the depletion period. Apparent Zn absorption continued to rise with continuing Zn depletion. Over a period of 6 weeks of Zn depletion the mean rate of Zn absorption was 58% with increases from 51% to 64% between the 1st and 6th week of experiment. After 19 weeks of Zn depletion 75% of the supplemented zinc were absorbed. With a Zn supply of 22 ppm and 54 ppm the rate of apparent Zn absorption decreased to 51% and 44% while still higher Zn supplements, up to 436 ppm, produced only a slight further decline down to 40%. The absolute Zn balances were shown to be directly associated with the level of Zn supply, all the more so because a linear relationship was found to exist between the levels of alimentary zinc supplementation and absolute Zn retention. Under conditions of Zn deficiency the cows exhibited a negative Zn balance, where animals with the highest milk yields showed the most negative Zn balances and remained for the longest period in the negative phase. With increasing periods of Zn depletion a homeostatic mechanism of Zn regulation in the organism of the animals became more and more pronounced so that at advanced stages of Zn depletion Zn retention of some extent occurred.     

Effect of dietary neutral detergent fiber concentration and forage source on performance of lactating cows

'Mott' dwarf elephantgrass, forage sorghum, 'Tifton 81' bermudagrass, and whole corn plant were stored as silage and fed as the only forage source in diets formulated to 31, 35, and 39% NDF. The 12 diets were fed for ad libitum intake as a TMR to midlactation Holstein cows, primarily to determine the effect of NDF concentration and forage source on DMI and milk production. Increased dietary NDF concentration linearly decreased DMI (3.69 to 3.35%) and OM intake (3.39 to 3.06%) as a percentage of BW and linearly increased NDF intake as a percentage of BW (1.15 to 1.32%). Production of milk (23.0 to 21.7 kg/d) and 4% FCM (20.7 to 19.6 kg/d) and percentage of milk protein (3.16 to 3.07%) decreased linearly as dietary NDF concentration increased. Cows fed dwarf elephantgrass silage or corn silage, which were higher quality forage sources based on greater rates and extents of fiber digestion, consumed more DM and produced more milk than cows fed sorghum silage or bermudagrass silage. Cows fed diets containing sorghum silage had the lowest DMI and milk production. Apparent digestibility of NDF and ADF from corn silage and dwarf elephantgrass silage was greater than that of sorghum silage and bermudagrass silage. In addition to dietary NDF concentration, digestibility of dietary fiber influences DMI and milk production.     

电感耦合等离子发射光谱法测定锂制品中的Cu、Pb、Zn、Ni、Ca、Mg、Mn、Cd

实验采用电感耦合等离子发射光谱法来测定锂制品中的Cu、Pb、Zn、Ni、Ca、Mg、Mn、Cd等杂质元素量,确定了用硝酸（1＋1）10 mL分解样品以及选择锂浓度为5 mg/mL基体效应最小;选择了适合本实验分析用的波长（Zn：213.856 nm;Ca：396.847 nm;Cd：228.802 nm;Cu：324.754 nm;Mg：280.270 nm;Mn：259.373 nm;Ni：231.604 nm;Pb：220.353 nm）;仪器功率选择1000 W;通过实验得出加标回收率为92%-110%,相对标准偏差小于5%;并确定Mn、Cd、Ni 、Zn的测定范围为0.00005%-0.0080%,Ca、Cu、Mg 0.0001%-0.0080%,Pb为0.0002%-0.0080%.     

Dietary variety via sweetening and voluntary feed intake of lactating dairy cows

The effects of choice of diets on feed intake were studied using 12 lactating Holstein cows. A switchback design was used that had three periods and two sequential blocks. Diets were 1) a control total mixed ration (TMR), which consisted of alfalfa haylage, corn silage, and a concentrate mixture based on ground corn and soybean meal (25:25:50 on a dry matter basis) and 2) a sweetened TMR in which a brown sugar food product constituted 1.5% of the dietary dry matter. Treatments consisted of the control TMR fed on both sides of divided feed bunks, the sweetened TMR fed on both sides of divided feed bunks, or both TMR fed on alternating (daily) sides of divided feed bunks in tie stalls. Periods were 2 wk in duration, and cows averaged 67 and 53 d of lactation at the start of blocks 1 and 2, respectively. The dry matter intake, body weight, milk yield, and percentages of milk fat, protein, and solids not fat were similar when either TMR was fed alone. A choice of control TMR or sweetened TMR did not affect any of these variables. The dry matter intake, body weight, milk yield, and milk protein percentage were affected by block; however, these effects were probably caused by differences between the blocks in environment and stage of lactation. The results of this experiment might have been affected by the composition of the control TMR, its similarity to the sweetened TMR, availability of both diets simultaneously when a choice was offered, and use of a TMR instead of separate feeds or simpler mixtures.     

Effects of a supplemental liquid yeast product on feed intake, ruminal profiles, and yield, composition, and organoleptic characteristics of milk from lactating Holstein cows

A liquid yeast product (about 11% DM), produced as a by-product of riboflavin synthesis, was incorporated into a TMR at three concentrations to determine the maximal inclusion rate and acceptability as a feed supplement in diets of lactating cows. Twelve Holstein cows in midlactation were randomly assigned to TMR treatments containing (as-fed basis) 1) no yeast product (control), 2) 20% dietary yeast product, or 3) 40% dietary yeast product in a 3 x 3 Latin square design with 3-wk periods. Dietary DM contents were 90, 74.2, and 58.4% for the 0, 20, and 40% yeast product TMR, respectively. The control TMR was based on a 45:55 ratio (DM basis) of mixed concentrate and chopped alfalfa hay. The DMI decreased linearly with increasing percentages of dietary yeast product. Milk yield and milk protein percentage were not altered by inclusion of the dietary yeast product. Milk fat tended to respond quadratically to increases in the percentage of dietary yeast product in the TMR. The supplemental dietary yeast product had no effect on ruminal pH; however, the ratio of acetate to propionate decreased, and propionate percentage tended to increase, as supplementation of the yeast product increased. Addition of yeast product to the TMR had no adverse effect on milk flavor. Milk from cows fed yeast product had better flavor than milk from control cows. Results indicate that inclusion of this yeast product at 40% depressed feed intake.     

电解分离-电感耦合等离子体发射光谱法测定纯铜中杂质元素

以硫硝混酸为电解液,控制电解电流为2 A,建立了电解分离-电感耦合等离子体发射光谱法测定纯铜中19种杂质元素（Mg、Bi、Al、P、Ti、Cr、Mn、Fe、Zn、Co、Ni、As、Se、Zr、Cd、Sn、Sb、Te 和 Pb）的方法。结果显示,在最佳实验条件下,大于99%的铜沉积至阴极,各杂质元素的回收率大于90%。研究了电解后电解液的酸效应和残余铜对测定的影响,结果表明,基体效应影响较小,可通过基体匹配来进一步消除其影响。各杂质元素的检出限在0.02～4 mg/kg之间。运用该方法测定纯铜标准物质GBW02141,各元素测定值与认定值吻合。以高纯铜空白样品做加标回收试验,除Bi外,各元素的加标回收率在90%～100%之间,相对标准偏差（RSD,n=5）在0.2%～7.2%之间。     

Effects on nutrient digestion of wheat processing and methods of tallow addition to the diets of lactating dairy cows

Five multiparous Holstein cows in midlactation that were fitted with ruminal and duodenal cannulas were used in a 3 x 5 incomplete Latin square. The objective of this study was to examine the effects on nutrient digestion of wheat processing and method of tallow addition to the diets of lactating dairy cows. Diets consisted of 45% forage and 55% concentrate, and each diet contained 20% wheat and 2% tallow (as-fed basis). Treatments were dry-rolled wheat with tallow added to the concentrate, steam-rolled wheat with tallow added to the concentrate, and steam-rolled wheat with tallow added first to the wheat. The dry matter intake; digestion of starch, fiber, and fatty acids; ammonia N concentration; and molar proportions of volatile fatty acids in ruminal fluid were not affected by treatments. The apparent digestibility in the total tract of organic matter and nitrogenous compounds was significantly higher for the steam-rolled treatment with tallow added first to the wheat. Mean ruminal fluid pH was similar across treatments; however, cows fed the diet containing steam-rolled wheat with tallow added first to the wheat had the smallest pH change from 0 to 2 h postfeeding. Milk yield did not differ, regardless of cow diet. Method of tallow addition had marked effects on the apparent digestibility of organic matter and N in the total tract of lactating dairy cows.     

超纯氧化铁制备及其在电感耦合等离子体原子发射光谱法测定高纯铁化合物中杂质元素的应用研究

用电感耦合等离子体原子发射光谱法(ICP-AES)准确测定高纯铁化合物中的痕量杂质元素,需要更高纯度的铁作为基体,以研究它对测定杂质元素的干扰。为此,以分析纯硫酸亚铁为原料制备了高纯氧化铁,制得的高纯氧化铁中杂质元素Al、Cd、Co、Cr、Cu、Mg、Mn、Ni和Zn等的含量低于方法检出限。用制备的高纯氧化铁作为标准系列溶液的基体,得到了基体匹配的标准系列溶液,用此标准系列溶液绘制的校准曲线测定了GBW01402d高纯铁标准物质中杂质元素的含量,其测定值与认定值一致。研究了用无基体匹配标准溶液测定高纯铁及铁化合物中Al、Cd、Co、Cr、Cu、Mg、Mn、Ni和Zn等杂质时的干扰校正方法,结果表明:Al、Co、Cr、Cu、Mg和Zn受到的光谱干扰仅需采用离峰法校正即可,而Cd、Mn和Ni受到的光谱干扰则必需采用多元光谱拟合法校正。用拟定的校正方法测定高纯铁化合物中的痕量杂质元素,准确度高的元素有Al、Cd、Cr和Cu,准确度稍差的元素有Co、Mg、Mn、Ni和Zn。     

Effect of Long-term Intake of Rare Earth in Drinking Water on Trace Elements in Brains of Mice

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Susceptibility to tropical theileriosis of calves born to dams immunized with Theileria annulata (Hisar) cell culture vaccine

Epidemiological evidence suggests that millet might play a role in the etiology of endemic goiter. Recently, we showed that a traditional fermentation procedure of two pearl millet (Pennisetum americanum L. Lecke) cultivars grown in Sudan modified their effects on the weight of the thyroid gland and thyroid hormone profile in rats. In the present study, we report that this fermentation procedure reduced the ash contents of millet by about 40% and removed considerable amounts of Mg (>50%), Zn (27-39%) and K (45%). Other minerals (Ca, Fe, Cu) were not affected. Feeding of one fermented cultivar resulted in significant reduction in bone Mg and Zn contents, whereas feeding of the other fermented cultivar resulted in reduction of bone Mg only. Dietary Mg intake and bone Mg contents correlated negatively with serum T3. Groups fed the millet diets had higher serum Se level compared to those fed wheat or casein diets and feeding of fermented millet resulted in a further increase in serum Se level. Thus our data indicate that in rats the enhanced effects of millet on the thyroid induced by fermentation is likely related to removal of minerals from millet and/or chemical transformation of the goitrogens contained in millet.     

Dietary Mg and/or K restriction enhances paraquat toxicity in rats

Effect of mineral restriction was studied to clarify which mineral in the diet is most indispensable in preventing paraquat (PQ) toxicosis. ODS rats were chosen as the experimental animal owing to the inability to synthesize vitamin C similarly to humans. Rats were fed with either mineral-adequate or restricted diets dosed with 125 ppm PQ. The mineral-adequate diet was based on the American Institute of Nutrition-76, and the restricted diet was one-half the amounts. Measurements were made on the onset day of PQ toxicosis, body weight changes during the feeding experiment, and changes of two acute phase reactant proteins cysteine proteinase inhibitor and alpha1-proteinase inhibitor. The minerals tested were divided into three classes: I, largely needed, Ca, K, Na, and Mg; II, moderately needed, Mn, Fe, Zn, and Cu; and III, minutely needed, Cr and Se, respectively. Rats fed with a Mg-restricted diet showed a severe toxicosis but those with a K-restricted diet, a mild toxicosis. No appreciable effect was observed by restriction of other minerals. A synergistic effect was observed in the restriction of Mg and K.     

The effects of low dietary copper intake during pregnancy on physiological fluids and reproductive performance of first-litter gilts

Seven pairs of first littermate gilts were used to study the influence of low copper supply and pregnancy on physiological fluids and reproductive performance of first-litter gilts. They were fed semi-purified diets containing either 2.13 or 12.25 micrograms/kg of Cu from 30 days of gestation through two weeks of lactation. Low-Cu gilts had lower plasma Cu in early- and mid- gestation and farrowed piglets with lower plasma Cu and higher plasma Zn concentrations (p < 0.05). Plasma Fe and Mn concentrations were not affected by Cu supply (p > 0.05). Plasma Cu and Fe levels of newborn piglets were lower than those of their dams (p < 0.05) but this was not true for plasma Zn and Mn (p > 0.05). Low-Cu gilts had lower Cu and higher Zn content in colostrum and also lower Cu in milk than control gilts (p < 0.05). No significant differences were found in Fe and Mn levels in colostrum and milk between the two treatments (p > 0.05). Colostrum was richer in Cu and Zn than milk (p < 0.05) but not in Fe and Mn (p > 0.05). The low-Cu diet did not affect (p > 0.05) weight changes during pregnancy. The duration of parturition was shorter for low-Cu than for control gilts (3.19h vs. 5.71h, p < 0.05). Control gilts farrowed larger litters than low-Cu gilts (9.71 vs. 7.57 piglets, p < 0.05). There were no significant differences in live litter weights at birth, one wk. or two wks. of age (p > 0.05). The results indicated that a low-Cu diet and pregnancy had some effect on plasma, colostrum and milk mineral concentrations, as well as on litter size of gilts. An interaction between Cu and Zn was found.     

ICP-AES法测定混合稀土金属及其化合物中的11个非稀土元素

采用全谱直读等离子光谱法测定混合稀土金属及其化合物中的钙、镁、铁、锌、铜、锰、镍、锶、钡、钴、铬,系统考察了不同基体及共存杂质元素对测定元素的影响,进行了加料回收及精密度实验,并用不同测定手段进行了比对实验。此方法准确、快速。     

Mussels and algae as bioindicators for long-term tendencies of element pollution in marine ecosystems

Results of more than ten years of experience in the determination of metals in mussels and algae collected in the North Sea and the Baltic Sea are presented. The various elements determined here are Hg, As, Se, Cd, Pb, Cu, Na, K, S, P, Zn, Mn, Fe, Sr, Ca, Ba, Mg, Tl, Ni, Co using techniques such as cold vapor AAS, INAA, hydride generation AAS, electrothermal AAS, ICP-AES, IDMS and stripping voltammetry. The results indicate the occurrence of three groups of elements with respect to long-term tendencies of their concentrations. In the first group, the concentrations in both mussels and algae varied in the same manner; in the second group no change was observed in either matrix while in the third group, the concentrations of elements changed in an opposite manner.     

微波消解-电感耦合等离子体质谱法测定钽酸锂中痕量杂质元素

钽酸锂中杂质元素含量是划分产品等级的重要参数.样品中加入硝酸和氢氟酸后用微波消解法溶解样品,在线加入1.00 μg/mL的Cs内标溶液后,在H2动态反应池模式下测定Ca、Fe、As、Se,在标准模式下测定其余元素,建立了微波消解-电感耦合等离子体质谱法(ICP-MS)测定钽酸锂中Be、B、Na、Mg、Al、K、Ca、T...