Differential effects of sodium and magnesium sulfate on water consumption by beef cattle

The existing guidelines for maximum sulfate (SO4) in cattle drinking water are based on Na2SO4, although many water sources contain greater concentrations of MgSO4. Two experiments compared the effect of different SO4 salts on water consumption and fecal DM of cattle. In Exp. 1, 8 yearling heifers (initial BW = 345 +/- 8 kg; mean +/- SD) were watered twice daily with tapwater or water containing Na2SO4 or MgSO4 at target levels of 1,500, 3,000, or 4,500 mg of SO4/L for 2-d treatment periods separated by 2 d of access to tapwater. In Exp. 2, 16 yearling cattle (initial BW = 421 +/- 24 kg) were watered twice daily with tap-water (16 mg of SO4/L) or water containing Na2SO4 at target levels of 2,000 mg of SO4/L (low Na2SO4), MgSO4 at 2,000 mg of SO4/L (low MgSO4), or MgSO4 at 4,000 mg of SO4/L (high MgSO4) in 21-d treatment periods separated by 7-d periods on tapwater. The first 10 d of each period were allowed for adjustment to the treatment, and the final 11 d was considered the treatment period for analysis purposes. Treatments were applied in an incomplete Latin square, where each animal was exposed to 3 of the 4 treatments. In Exp. 1, the average daily water consumption decreased linearly as the SO4 concentration increased for MgSO4 (P = 0.0001) but not for Na2SO4 (P = 0.39). In Exp. 2, the average daily water consumption was less for cattle on the high-MgSO4 treatment than for cattle on the low-MgSO4 treatment (P = 0.0001), and cattle on the low-MgSO4 treatment tended (P = 0.09) to drink less than those on the tap-water treatment. Fecal DM was greater for cattle on the high-MgSO4 treatment than for those on the low-MgSO4 treatment (P < 0.01). These findings indicate that cattle reduce their consumption of water containing high (> or = 4,000 mg of SO4/L) concentrations of MgSO4, even after a given time to adjust to the treatment; such reductions may be accompanied by an increase in fecal DM.     

Estimation of the relative biological availability of inorganic selenium sources for ruminants using tissue uptake of selenium

An experiment was conducted to estimate the relative bioavailability of inorganic Se sources based on tissue Se deposition following supplementation at high dietary levels. Twenty-eight crossbred wethers averaging 50 kg initial weight were assigned randomly to seven treatments that were fed for 10 d. The basal diet contained .18 mg/kg Se (DM basis). Dietary Se was added at 0, 3, 6 or 9 mg/kg as reagent grade sodium selenite (Na2SeO3) and 6 mg/kg from either calcium selenite (CaSeO3), Na2SeO3 + fumed amorphous carrier or sodium selenate (Na2SeO4). There were four sheep per treatment group, housed in individual, raised pens with slatted floors. Daily feed intake was restricted to 1,200 g and tap water was available ad libitum. The basal diet was fed for a 10-d adjustment period, then sheep were fed experimental diets for 10 d. At the termination of the experiment, blood samples were taken; sheep were stunned and killed, and livers and kidneys were removed and frozen for Se analysis. There was a linear (P less than .001) uptake of Se in liver, kidney and serum. The CaSeO3 and Na2SeO4 sources resulted in greater (P less than .05) Se concentrations in liver and kidney than did Na2SeO3, but these differences were not significant when the analyzed dietary Se concentrations were used as a covariate in the statistical model. Based on linear and multiple linear regression slopes and average increases in serum, liver and kidney Se concentrations, estimated relative bioavailability values corrected for analyzed dietary concentration, were 100, 101, 90 and 133 for Na2SeO3, CaSeO3, Na2SeO3 + carrier and Na2SeO4, respectively.     

Comparison of cupric and sulfate ion effects on chronic selenosis in rats

The ameliorating effects of Cu++ and SO4--ions on concurrent selenite toxicity were compared in two factorial experiments using 60 weanling rats each. In the first experiment, 0, 500 and 1,000 mg Cu (as CuCl2)/kg diet were fed in conjunction with 0, 5, 10 and 20 mg Se (as Na2SeO3)/kg diet. In the second experiment, the treatments were 0, 500 and 1,000 mg SO4 (as Na2SO4)/kg fed in conjunction with 0, 5, 10 and 20 mg Se/kg diet. A paired-feeding experiment using 10, 15 and 20 mg Se/kg diet was also conducted with 28 rats to compare the influence of inanition in control and selenite-fed rats. Cupric++ ion, but not SO4--ion, prevented mortality among selenite-intoxicated rats. There were significant Cu X Se interaction effects on feed intake, daily gain, packed cell volume (PCV), serum Cu and Fe, sperm counts, and weights of liver, kidney and testis. There were main effects of Cu and Se on serum Se and liver Cu. In Exp. 2 there were significant SO4 X Se interaction effects on feed intake, daily gain, serum Cu and testis weight. There were main effects of Se on PCV, sperm count, serum testosterone, liver Se, liver Cu and the absolute weights of liver and kidney. The only main effect of SO4 was that of increased liver Cu concentrations. Among the pair-fed rats, the selenite-fed rats, with one exception, died before their paired rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Methionine, choline and sulfate interrelationships in the diet of weanling swine

Experiments were conducted to examine the interrelationships between methionine, choline and inorganic sulfate in the diet of weanling pigs, and to evaluate the selenium (Se) status of pigs fed diets with or without supplemental sulfate. Two trials utilized 288 weanling (3-wk-old) pigs allotted to dietary treatment based on weight, sex and litter origin. There were six pigs/pen and three replicate pens/treatment in each trial. The basal corn-soybean meal diet was formulated to supply .55% sulfur amino acids and contained a choline and sulfur-free vitamin and mineral premix. Lysine was added to provide a total of 1.13% lysine. Seven additional treatments were formulated by substituting for corn .17% DL-methionine, .29% choline dihydrogen citrate or .25% Na2SO4 to create a 2(3) factorial arrangement of treatments. There were methionine X choline X sulfate interactions for average daily gain (P less than .001) and feed-to-gain ratio (F:G; P less than .05). Adding choline, methionine, Na2SO4 or choline plus methionine to the basal diet did not improve gains. However, when Na2SO4 plus methionine or Na2SO4 plus choline were added, daily gains were increased (P less than .05) and F:G was improved (P less than .1). Addition of all three supplements did not result in a further increase in gain. Pigs fed choline-supplemented diets had higher (P less than .01) hematocrit and tended (P = .07) to have increased hemoglobin concentration. There was no effect on serum triglycerides or alkaline phosphatase activity due to dietary treatment. The concentration of Se in muscle, liver, kidney and blood was not influenced by sulfate content of the diet.     

3种盐胁迫对蓟幼苗生长及生理生化的影响

采用盆栽试验研究不同浓度(0.1%、0.2%、0.3%、0.4%、0.5%、0.6%)的NaCl、Na_2SO_4、Na_2CO_3对蓟(Cirsium japonicum)幼苗苗高、叶片相对含水量、丙二醛(MDA)、抗氧化酶(POD、SOD、CAT)以及渗透调节物质(可溶性糖、游离脯氨酸)的影响。结果表明,除0.1%NaCl处理蓟苗高和叶片相对含水量高于无盐胁迫(CK)外,其余处理均低于CK,且随盐浓度增加而降低,其中,0.3%NaCl、0.4%Na_2SO_4和0.1%Na_2CO_3处理下苗高依次为CK的62.15%、58.00%和45.77%,而0.5%Na_2CO_3处理幼苗死亡;随盐处理浓度增加和处理时间延长,叶片中丙二醛含量均呈上升趋势;POD、SOD、CAT活性随盐浓度、时间变化的趋势不尽一致,3种酶活性均出现了阈值,POD出现在0.3%NaCl、0.3%Na_2SO_4、0.4%Na_2CO_3胁迫5d,SOD出现在0.3%NaCl处理3d、0.5%Na_2SO_4处理1d、0.4%Na_2CO_3处理3d,CAT出现在0.3%NaCl、0.2%Na_2SO_4、0.1%Na_2CO_3胁迫3d;相同处理时间下,随盐浓度的增加,除NaCl胁迫下游离脯氨酸(Pro)含量先增后减外,Na_2SO_4和Na_2CO_3胁迫下游离脯氨酸含量,以及3种盐胁迫下可溶性糖(SS)含量均逐渐增加。综上认为,蓟对NaCl、Na_2SO_4、Na2CO4这3种盐均具有一定的耐性,可以在低于0.3%NaCl、0.4%Na_2SO_4和0.1%Na_2CO_3条件下生存和生长。     

新疆放牧绵羊的限制性矿物质元素调查

通过新疆5个羊场矿物质元素营养的研究，以了解新疆全年草场有关矿物元素的变化情况，缺乏程度及缺乏时间。研究表明：5个羊场中牧草含P量在秋草场至冬草场均表现缺乏。含Na量在塔城种羊场一年四季草场均缺乏，在阿勒泰二牧场冬、春、夏草场Na出现明显缺乏，而在秋草场又明显超出需要量；在巩乃斯种羊场春、夏草场明显缺乏，冬、牧草场又明显超量。5个羊场牧草含Se、Zn量的测定值明显低于需要量。而含Fe量在5个羊场中都不同程度地超过最高限量。牧草中元素Fe与Mn之间存在措抗作用；Mo、Cu比例少于1：4，绵羊体内仍表现缺Cu症。通过全面分析对比，初步确定在新疆5个种羊场天然草场上放牧的羊群，存在着P、Na、Zn、Mn、Se和Cu6种限制性矿物元素季节性营养紊乱现象。     

Movement of nutrient and non-nutrient elements in the liquid phase in sheep rumen

Changes in the concentrations of B, Ca, Fe, K, Mg, Mn, Na, P, S, Sr and Zn in the liquid phase in sheep rumen were determined to obtain information on their rate of disappearance from the soluble pool after feeding. Sheep were fed alfalfa (Medicago sativa) hay hourly. The concentration of infused Cr(III)-EDTA into the rumen (over a period of 4 d) was used to establish steady-state conditions, after which feeding was stopped and the rapidly changing elemental concentrations in 30,000 x g ruminal supernatant fluid were determined by plasma emission spectrometry. The concentrations of all elements, apart from Fe, Na and P, decreased in a first-order manner over 5 h after feeding. For one sheep, these concentrations (microM) were: B, 199 to 126; Cr, 184 to 111; Ca, 4,150 to 1,130; K, 51,000 to 28,800; Mn, 11 to 4.2; Mg, 4,190 to 1,810 and Zn, 14 to 7.8. For S, first-order decay was observed over only the 0- to 2-h period (2230 microM to 865 microM). Phosphorus increased from 10.4 to 13.1 mM over the 5-h period, whereas Na remained constant (85 mM); this was attributed to saliva input. Mean half-lives for B (8.8 h), K (7.5 h) and Zn (5.3 h) were similar to those of Cr (6.3 +/- .3 h), the water flow marker. Mean half-lives of Ca (2.6 h), Mg (4.0 h), Mn (3.3 h), Sr (3.3 h) and S (1.8 h) were shorter (P less than .01) than that of the Cr marker.(ABSTRACT TRUNCATED AT 250 WORDS)     

盐分对碱茅种子发芽影响的机制

耐碱茅种子在盐（NaCl与Na2SO4）及干旱（PEG－6000模拟）胁迫下发芽及其机制的比较研究表明，种子发芽率随溶液渗透势的降低而下降，在等渗条件下三种溶液中的发芽率次序为Na2SO4＞NaCl＞PEG。NaCl与Na2SO4主要通过影响种子吸水量及对膜的毒性影响发芽，根据相关及通径分析结果，其机制为：（1）溶液渗透势及Na+浓度决定的种子吸水对发芽的直接正效应（通径系数0．73）；（2）溶液Na+浓度引起的膜毒性对发芽的直接负效应（－0．51）；（3）种子从溶液中吸收Na使种子吸水增加对发芽的间接正效应（0．30）及使膜毒性增大对发芽的间接负效应（－0．24）。     

Changes in the renal handling of urea in sheep on a low protein diet exposed to saline drinking water

Previous trials have demonstrated that sheep on a low protein diet and free access to water, and sheep dosed with boluses of NaCl intraruminally also with free access to water, showed decreases in urea loss via the urine compared to control animals. We monitored urea excretion in sheep on a relatively poor protein diet when they were exposed to saline drinking water, i.e. they were unable to vary their intake of NaCl:water. Sheep on isotonic saline drinking water (phase 3) excreted significantly more urea via the urine (284 mM/day) compared to phase 1 when they were on non-saline drinking water (urea excretion = 230 mM/day) and phase 2 when they were on half isotonic saline drinking water (urea excretion = 244 mM/day). This finding was explained by the high glomerular filtration rate (GFR) 91.9 l/day, compared to 82.4 l/day (phase 1) and 77.9 l/day (phase 2), together with a significantly raised fractional excretion of urea (FEurea) (51.1 %) during this phase, and was in spite of the significantly lower plasma concentrations of urea in phase 3 compared to phase 1. The FEurea probably results from the osmotic diuresis caused by the salt. There were indications of a raised plasma antidiuretic hormone (ADH) concentration and this would have opposed urea loss, as ADH promotes urea reabsorption. However, this ADH effect was probably counteracted to some extent by a low plasma angiotensin II concentration, for which again there were indications, inhibiting urea reabsorption during the phases of salt loading. As atrial natriuretic peptide both increases GFR and decrease sodium reabsorption from the tubule, it was probably instrumental in causing the increase in GFR and the increase in the fractional excretion of sodium (FE(Na)).     

Excessive oral administration of iron to sheep. 1. Digestibility of rations, results of fattening and carcass yields]

4 digestibility trials (4 male sheep per group) and 2 growth trials were carried out with 24 (V 1) and 32 (V 2) fattening lambs to investigate the effect of abundant oral Fe doses on the digestibility of crude nutrients in a ration of barley + dried green feed and on the results of fattening and carcass yields. Fe supplementation (less than 1400 mg per sheep/day) did not significantly change the digestibility coefficients of crude nutrients. Increasing Fe levels in the concentrates decreased the rates of liveweight increase and food consumption in both growth trials. Well-established statistical evidence was provided for the decline in absolute carcass yields resulting from the lower weight of the lambs at the end of the fattening period after Fe supplementation.     

Influence of sulfate in drinking water on mouse reproduction during two parities

Field studies have suggested that high levels of sulfate in drinking water may alter water consumption and have an adverse effect on animal reproduction. This study was conducted to determine whether sulfate in the drinking water affects the reproductive performance of female mice during gestation and lactation over two parities. Sixty random-bred albino mice were randomly assigned to six sulfate treatments. Sodium sulfate was added to deionized distilled water to give sulfate levels in ppm as follows: (1) 0 (control); (2) 0 (Na control); (3) 625; (4) 1,250; (5) 2,500 and (6) 5,000. Treatments 2 to 6 contained the same Na content (2,392 ppm) by varying Na bicarbonate content. Mice receiving only the deionized distilled water drank less (P less than .05) than mice receiving the other treatments at all times measured. Animals offered the 0 (Na control) water drank more (P less than .05) water than mice on the other sulfate treatments. There was no difference (P greater than .10) in litter size, litter weaning weight, or gestational and lactational weight gain of the dam among water treatments. Although levels of sulfate up to 5,000 ppm and 2,392 ppm Na in the drinking water cubicly altered water consumption, they did not affect litter size, litter weaning weight, or gestational and lactational weight gain of the dam when sulfate ingestion was continued over two parities.     

盐胁迫对达乌里胡枝子种子萌发的影响

通过对达乌里胡枝子在浓度为1、2、3、6、7、8、9、10、11、12、13、14、15 mg/L的NaCl,Na2CO3和Na2SO4胁迫下种子发芽的试验研究。结果表明:在3种盐不同浓度的胁迫下,种子的发芽率均低于对照,在NaCl胁迫下,盐浓度为8 mg/L时发芽率最高,浓度为10 mg/L时发芽率出现一低峰;在Na2SO4处理下,盐浓度为10 mg/L时发芽率也出现一低峰;在Na2CO3处理下,浓度为6 mg/L时所有种子不发芽;NaCl处理组种子发芽率高于Na2SO4处理组,3种盐的耐受程度大小为:NaCl>Na2SO4>Na2CO3。     

外源抗坏血酸引发促进Na_2SO_4胁迫下燕麦幼苗的生长

通过不同浓度(0、0.5、1.0、1.5和2.0 mmol·L^-1)的抗坏血酸(As A)引发燕麦(Avena sativa)种子,并在浓度为0、50和100 mmol·L^-1的Na2SO4胁迫下进行标准发芽,分析其幼苗芽长(LS)、根长(LR)、芽鲜重(FWS)、根鲜重(FWR)及幼苗活力指数(SVI)的变化,探讨了外源As A引发对Na2SO4胁迫下燕麦幼苗生长的影响。结果表明,燕麦幼苗LS、LR、FWS和SVI随Na2SO4胁迫程度增强而显著(P<0.05)降低,但其FWR则呈先升后降的趋势。As A引发处理能提高其LS、LR、FWS、FWR和SVI,这表明As A引发能够提高Na2SO4胁迫下燕麦幼苗的生长能力。Na2SO4与As A浓度对燕麦LS、LR、FWS、FWR和SVI的影响差异极显著(P<0.01),二者的交互作用对燕麦幼苗LS、LR、FWS和FWR的影响也有极显著(P<0.01)差异,因而表明As A引发效果与As A和Na2SO4浓度及其交互作用具有密切关系,试验中As A引发的最佳浓度为1.5 mmol·L^-1。     

Effects of enteral and intravenous fluid therapy, magnesium sulfate, and sodium sulfate on colonic contents and feces in horses

OBJECTIVE: To assess changes in systemic hydration, concentrations of electrolytes in plasma, hydration of colonic contents and feces, and gastrointestinal transit in horses treated with IV fluid therapy or enteral administration of magnesium sulfate (MgSO4), sodium sulfate (NaSO4), water, or a balanced electrolyte solution. ANIMALS: 7 horses with fistulas in the right dorsal colon (RDC). PROCEDURE: In a crossover design, horses alternately received 1 of 6 treatments: no treatment (control); IV fluid therapy with lactated Ringer's solution; or enteral administration of MgSO4, Na2SO4, water, or a balanced electrolyte solution via nasogastric intubation. Physical examinations were performed and samples of blood, RDC contents, and feces were collected every 6 hours during the 48 hour-observation period. Horses were muzzled for the initial 24 hours but had access to water ad libitum. Horses had access to hay, salt, and water ad libitum for the last 24 hours. RESULTS: Enteral administration of a balanced electrolyte solution and Na2SO4 were the best treatments for promoting hydration of RDC contents, followed by water. Sodium sulfate was the best treatment for promoting fecal hydration, followed by MgSO4 and the balanced electrolyte solution. Sodium sulfate caused hypocalcemia and hypernatremia, and water caused hyponatremia. CONCLUSIONS AND CLINICAL RELEVANCE: Enteral administration of a balanced electrolyte solution promoted hydration of RDC contents and may be useful in horses with large colon impactions. Enteral administration of either Na2SO4 or water may promote hydration of RDC contents but can cause severe electrolyte imbalances.     

Effect of Drinking Water Iron Concentration on Broiler Performance

Many parts of the nation have elevated Fe concentrations in drinking water, and poultry producers are uncertain of the effect this will have on broiler performance. Three trials were conducted to evaluate the effects of Fe concentration on broiler performance. At hatch, Cobb 500 male broiler chicks were placed in Petersime batteries equipped with a nipple watering system. Chicks were weighed and randomly allotted to pens such that each pen had a similar weight distribution. Chicks were fed a standard corn-soybean meal diet to meet or exceed NRC recommendations. Chicks were allowed ad libitum access to feed and water. Weekly chick weight, feed intake, and water consumption were recorded throughout the 35-d trials. Soluble P in the manure was analyzed in Experiments 1 and 2. In Experiments 1 and 2, 4 water treatments consisted of 0, 2, 20, and 200 ppm supplemental Fe (FeSO₄·7H₂ O). In Experiment 3, the treatments were 0, 200, 400, and 600 ppm supplemental Fe. Water treatments were mixed on a weekly basis.No differences were noted in BW, feed consumption, water consumption, mortality, or manure-soluble P in any of the trials. None of the birds in the treatments exhibited any signs of flushing or any other intestinal problems. These results indicate that Fe concentrations in water do not affect performance or soluble P in broilers. Broiler performance was not affected by elevated SO₄ levels or reduced water pH. Although Fe may not have a direct affect on broiler performance, this study did not take into account the effect that high levels of Fe or its oxidized byproducts may have on equipment function.     

Low-quality roughages in high-concentrate pelleted diets for sheep: digestion and metabolism of nitrogen and energy as affected by dietary fiber concentration

Two trials were conducted to evaluate effects of, and interactions between, level and source of fiber in the diet on ruminal environment, microbial protein synthesis, nutrient digestion and flow of digesta through the gastrointestinal tract of multiple-fistulated sheep (trial 1; 4 X 4 Latin square design) and on ruminal, digestive and metabolic characteristics of early-weaned lambs (trial 2; randomized complete block design; 3 periods). All diets tested were pelleted and were formulated to contain either 39% or 25% neutral detergent fiber (NDF), with corncobs or cottonseed hulls (CSH) as the major NDF (roughage) sources. In trial 1, dry-matter (DM) and organic-matter (OM) digestibilities were not different (P greater than .05) among treatments. Digestibility of NDF was higher (P less than .05) with high-fiber. Bacterial N synthesis (g N/kg OM truly digested) was not different (P greater than .05) among treatments. Molar proportion acetate was higher (P less than .05) and molar proportion propionate lower (P less than .05) when sheep were fed high-fiber diets. In trial 2, apparent DM digestibility was higher (P less than .05) for lambs fed diets containing corncobs. Energy digestibility was higher (P less than .05) at the low-fiber level and for lambs fed diets containing corncobs. Apparent NDF digestibility by lambs was higher (P less than .05) at the high-fiber level and for lambs fed diets containing corncobs. Nitrogen retained (percentage of N intake) was higher (P less than .05) for lambs fed diets containing CSH. Ruminal pH and molar proportion acetate were higher (P less than .05) and molar proportion propionate lower (P less than .05) for lambs fed high-fiber diets. Although responses to corncob vs CSH inclusion in high-energy pelleted diets differ, both roughages are effective as fiber sources in sheep diets.     

Net absorption and oxygen consumption by Holstein steers fed alfalfa or orchardgrass silage at two equalized intakes

The objective of this experiment was to compare net nutrient absorption and oxygen consumption by portal-drained viscera (PDV) of catheterized Holstein steers (333 kg) when fed alfalfa or orchardgrass silage at two equalized intakes. The design was a 4 X 4 Latin square with a 2 X 2 factorial arrangement of alfalfa or orchardgrass fed at 65 or 90 g dry matter/kg.75 live weight daily. Blood flow through PDV (dilution of p-aminohippurate), net nutrient absorption and oxygen consumption (venoarterial concentration differences times blood flow) were measured hourly for 12 h, followed by measurement of N and energy balance over 7 d. Compared with orchardgrass, steers when fed alfalfa absorbed more NH3-N (P less than .05), branched-chain volatile fatty acids (P less than .10) and n-valerate (P less than .05). Silage type did not affect (P greater than .10) blood flow to or O2 consumption by PDV or net absorption of glucose, L-lactate, acetate, propionate, urea-N, alpha-amino N or most amino acids. Oxygen consumption by PDV as a percentage of whole-animal O2 consumption was not different (P greater than .10) for steers when fed orchardgrass (27.2) or when fed alfalfa (23.6). Interrelationships between N and energy metabolism were responsible for the increased (P less than .05) metabolizable energy/kilogram silage dry matter and increased (P = .10) N retention by steers when fed alfalfa compared with orchardgrass. The PDV accounted for a substantial portion of whole-animal O2 consumption.     

Effect of water restriction and dietary sodium on nutrient metabolism in lambs

Twenty-four Hampshire X Suffolk wether lambs (40 kg) were used in 2 X 2 factorial arrangement of treatments to study the influence of water restriction and high levels of dietary Na on nutrient utilization. Lambs were offered either a normal Na diet (.20% Na) or a high Na diet (1.77% Na). Additionally, the lambs were offered either a normal quantity of water (previously determined voluntary intake of lambs fed normal Na levels) or were restricted to a water intake 80% of normal. Each lamb received 800 g/d of a hay-corn diet (77.5% fescue hay) with an additional 38 g of NaCl offered to lambs on high Na treatments. The complete experiment consisted of 14 d of adjustment and 7 d of total collection with blood and ruminal characteristics measured on the last day of the collection period. A high Na intake decreased (P less than .05) the apparent digestibility of neutral detergent fiber, but tended to increase the apparent absorption of Mg. Plasma urea N concentrations were not affected (P greater than .05) by level of Na or water intake. Plasma Na and K concentrations were not affected (P greater than .05) by treatment regimen. A high Na intake increased (P less than .05) plasma Mg concentrations at 6 h post-feeding with a normal level of water intake, but decreased (P less than .05) Mg concentrations at 6 h with restricted water intake. Ruminal ammonia N and K concentrations at 2 h post-feeding were decreased (P less than .05) by a high level of dietary Na. Ruminal Na concentration was not affected (P greater than .05) by treatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

钼对羊的中毒性试验

选择杂交波尔山羊8只, 小尾寒羊2只(4组), 分为5组, 前四组每日依次灌服150、100、60、100mg的钼(Na2MoO4·2H2O), 5d后剂量减半; 5组灌自来水。试验45d。结果表明: 试验羊出现磨牙、咳嗽、呻吟、跛行、腹泻及贫血等明显的临床症状。各试验组RBC、Hb和PCV均显著低于对照组; 1组RBC、MCV、MCH极显著低于3组(P<0 01); 4组PCV、MCV、MCH极显著低于2组(P<0 01 ), Hb显著低于2组(P<0 05)。剖检表明, 试验组羊尸体消瘦, 血液稀薄; 肝脏肿大且发生脂肪变性; 肾脏体积肿大, 肾小管上皮细胞肿胀; 肠黏膜肿胀、出血, 小肠壁有红白相间的花斑样病理变化。     

不同盐胁迫对长穗偃麦草种子萌发及幼苗生长的影响

采用不同浓度NaCl、Na2SO4、NaHCO3、Na2CO3单盐溶液对长穗偃麦草种子进行胁迫处理,测定种子发芽率、发芽势、发芽指数、活力指数以及幼苗芽长和根长等指标,研究长穗偃麦草种子在不同盐胁迫条件下的萌发特性。结果表明,与用蒸馏水培养的对照相比,随着NaCl、Na2SO4、NaHCO3、Na2CO3单盐浓度的增加,长穗偃麦草种子发芽率、发芽势、发芽指数、活力指数均呈下降趋势。NaCl、Na2SO4、NaHCO3、Na2CO3对胚芽长和胚根长的抑制规律一致,表现为随盐浓度升高抑制作用增强,且胚根比胚芽对盐浓度反应更敏感;但是低浓度NaHCO3对胚根生长有一定的促进作用。4种单盐对长穗偃麦草种子萌发的抑制作用总体表现为:二价盐>一价盐。