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1.
Food and Drug Administration regulations currently permit addition of .3 mg of Se per kilogram of diet for chickens, turkeys, ducks, swine, sheep, and cattle. However, field reports indicate that this level may not be adequate for ruminants in all situations. Because sodium selenite is the most common supplemental form and is known to be readily absorbed to particles or reduced to insoluble elemental Se or selenides in acid, anaerobic environments, studies were conducted with dairy cattle, sheep, and horses fed sodium selenate to determine whether Se from this source was more bioavailable than Se from sodium selenite. A 2-wk period of no Se supplementation was followed by 49 or 56 d of Se supplementation at .3 mg/kg of dietary DM. Serum Se concentrations and glutathione peroxidase (GSHPx) activities measured initially and periodically thereafter revealed no difference between Se forms in sheep and horses and only a small (P less than .05) advantage for selenate in supporting serum Se concentration in dairy cattle. Selenium concentrations in skeletal muscle and liver of sheep were not different between Se forms. Serum Se, but not GSHPx, increased with time, and .3 mg of supplemental Se per kilogram of dietary DM from either sodium selenate or sodium selenite supported normal serum Se concentrations in sheep, dairy cattle, and horses.  相似文献   

2.
A continuing, sporadic incidence of vitamin E-selenium (Se) responsive disease among confinement-reared pigs believed to be fed complete and adequately supplemented diets prompted these studies on the potential genetic influence over vitamin E and Se metabolism in pigs. The initial study revealed a wide range of serum Se and vitamin E concentrations among age-matched, commonly housed and commonly fed growing pigs. Pigs found relatively hyposelenemic (hypo-Se) or hyperselenemic (hyper-Se) early in life retained their relative Se status while commonly reared. The persistence of vitamin E status was poor. Selected matings between identified, relatively hypo-Se gilts and boars and between relatively hyper-Se gilts and boars produced similarly affected baby pigs. In Exp. 2, representative hypo-Se (20) and hyper-Se (20) pigs were identified from a total of 107 baby pigs by 30 d of age. These pigs were allotted to an experiment to compare the responses of these two populations to .1 and .3 ppm supplemental dietary Se through 150 d of age. The difference in mean serum Se of the selected hypo- and hyper-Se pigs fed .1 ppm Se was significant at each sampling time. This difference approximated that observed between pigs (either hypo- or hyperselenemic) fed .1 and .3 ppm Se. The increase in serum Se due to .3 ppm supplemental dietary Se was greater among the selected hypo-Se pigs than among the hyper-Se pigs. Plasma Se-dependent glutathione peroxidase (GSH-Px) was a better indicator of dietary or serum Se status than was erythrocyte GSH-Px. The selected hyper-Se pigs maintained a more rapid rate of growth than did the hypo-Se pigs and were approximately 10 kg heavier at 150 d than the hypo-Se pigs.  相似文献   

3.
An experiment evaluated the selenosis effects from feeding high dietary Se levels of organic or inorganic Se sources to growing gilts with the dietary treatments continued through a reproductive cycle. A total of 88 gilts were allotted at 25 kg BW to two replicates in a 2 x 4 factorial arrangement in a randomized complete block design. Inorganic Se (sodium selenite) or organic (Se-enriched yeast) Se were added to diets at 0.3, 3, 7, or 10 ppm Se. At 105 kg BW, four gilts per treatment were killed and livers collected for Se analysis. At 8 mo of age, three gilts from each treatment group were bred and fed their treatment diet, with subsequent reproductive performance and selenosis effects evaluated. Serum collected at various intervals in gilts, sows, and progeny measured glutathione peroxidase activity and Se concentrations. Sow colostrum and milk was analyzed for their Se concentrations. Three pigs per treatment were killed before colostrum consumption and at weaning (14 d) and tissue collected for Se analysis. Gilt gains (P < 0.01) and feed intakes (P < 0.05) declined during the grower period as dietary Se level increased for both Se sources. Serum and liver Se concentrations increased as dietary Se level increased and was higher when organic Se was fed (P < 0.01). Sows fed dietary Se levels at > 7 ppm had lower gestation weights (P < 0.05) and lower lactation feed intakes (P < 0.05). As Se level increased, sows fed organic Se had a lower number of live pigs born (P < 0.05) and weaned fewer pigs (P < 0.05) with lower litter gains (P < 0.05) than did sows fed inorganic Se. Colostrum and milk Se concentrations increased as dietary Se levels increased particularly when organic Se was fed (P < 0.01). Neonatal and weanling pig tissue Se and serum Se concentrations increased as dietary Se level increased and when organic Se was fed, resulting in interaction responses (P < 0.01). Pigs nursing sows fed > 7 ppm inorganic Se had hoof separation and alopecia, with the severity being greater when sows were fed the inorganic Se source. These results suggest that both the organic and inorganic Se sources were toxic when fed at 7 to 10 ppm for a prolonged period, but organic Se seemed to express the selenotic effects more on reproductive performance, whereas inorganic Se was more detrimental during lactation.  相似文献   

4.
ABSTRACT

In New Zealand, the recommended intake of Se for dairy cattle (0.03?mg/kg dry matter (DM)) is lower than in the United Kingdom and Australia (0.1 and 0.04?mg/kg DM, respectively), and much lower than in the United States of America (0.3?mg/kg DM). Advisors in New Zealand often suggest that New Zealand intake recommendations are far too low and that recommendations from the United States of America should be used. This has created confusion as farmers are given very different advice depending on which recommendations their advisor uses. In this review, we assess whether the published evidence supports the existing dietary requirements and associated Se status thresholds, or if change is required. We focus particularly on the evidence-base in cattle fed a primarily pasture-based diet, as it is critical that dietary recommendations are derived from data created using cows fed similar diets. Accordingly, we also consider whether the increased use of fodder crops, especially during the dry period, is likely to have altered the Se requirements of dairy cows in New Zealand. We report that the science behind the dietary requirements for Se is robust, being supported by factorial models validated using New Zealand data, and on-farm experimental studies. Published nutritional data suggest that the increased use of fodder crops is unlikely to have altered the dietary balance of pro- and antioxidant factors in New Zealand dairy cows in a way that would meaningfully affect Se requirements. However, the lack of specific data on the vitamin E and fatty acid content of the crops being fed in New Zealand means that more information is needed to confirm this conclusion. In general, the existing New Zealand recommendations for Se-status thresholds are supported, although studies are still lacking to properly characterise the upper threshold of the marginal range. Nevertheless many studies in New Zealand, of herds with marginal or low adequate Se status (using New Zealand recommendations), have failed to show an effect of Se supplementation on milk production, intramammary infection or reproductive performance, so it is highly unlikely that the upper threshold of the range is much higher than the current recommendation. Proponents of the hypothesis that Se intakes in New Zealand dairy cattle should be increased by at least 10 times the current recommendations are therefore not using the evidence base correctly.  相似文献   

5.
Pigs from sows fed a diet deficient in Se and low in vitamin E were fed a Torula yeast diet supplemented with 100 IU dl-alpha-tocopheryl acetate/kg of diet. Dietary treatments were levels of supplemental Se of 0, .025, .050, .075 or .100 ppm. Some death loss occurred in pigs receiving no supplemental Se at approximately 5 wk of age. Autopsy revealed liver and heart lesions typical of vitamin E-Se deficiency. Selenium supplement had no significant effect on average daily gain, feed intake or gain to feed ratio for the 4-wk experiment. Selenium status of pigs was determined by serum Se concentration and serum glutathione peroxidase (GSH-Px) activity. Serum Se increased linearly (P less than .01) with increasing supplemental Se. Serum GSH-Px activity increased linearly (P less than .01) and quadratically (P less than .05) with increasing supplemental Se. With time, the level of serum Se and GSH-Px activity decreased in unsupplemental pigs, but increased in pigs fed diets supplemented with Se and resulted in significant interactions (P less than .01) between dietary Se level and time on experiment. The correlation between serum Se concentration and GSH-Px activity was .81 (P less than .01).  相似文献   

6.
This experiment evaluated the effect of high dietary Se levels using organic or inorganic Se on the selenosis responses in growing-finishing swine. A 2 x 4 factorial arrangement of treatments in a randomized complete block design was conducted in two replicates. Sodium selenite or Se-enriched yeast was added at 5, 10, 15, or 20 ppm Se to corn-soybean meal diets. A basal diet without added Se was a ninth treatment group. Ninety crossbred barrows initially averaging 24.7 kg BW were allotted at five pigs per pen. Pigs were bled at 3-wk intervals and plasma Se, glutathione peroxidase (GSH-Px) activity, glutamic oxalacetic transaminase (PGOT), hemoglobin, packed cell volume, and blood cell Se concentration were measured. After 12 wk, pigs were killed and various tissues and bile were collected for Se analyses. Pig body weights, daily gains, and feed intakes were similar for both Se sources when provided at < or = 5 ppm Se, but each measurement declined in a different manner for each Se source as the dietary Se level increased. The decline was more rapid when the inorganic rather than organic Se source was fed, resulting in interaction responses (P < 0.01). Hair loss (alopecia) and separation of the hoof at the coronary band site occurred at > or = 10 ppm inorganic Se but at > or = 15 ppm organic Se level. Plasma GSH-Px activity increased (P < 0.01) when high dietary Se levels of either Se source was fed. Plasma and blood cell Se increased at each period as dietary Se level increased (P < 0.01) and was greater when organic Se was provided (P < 0.05). Blood cell Se concentration reached a plateau when inorganic Se, but not when organic Se, was fed and increased as the experiment progressed. This resulted in a three-way interaction (P < 0.01). Plasma GOT activity at the 12-wk period was elevated when inorganic Se was provided at > or = 15 ppm Se but not when organic Se was fed, resulting in an interaction (P < 0.05). Tissue Se concentrations increased as dietary Se level increased and when organic Se was provided, resulting in interaction responses (P < 0.05). Bile was a yellow color when the basal diet was fed but was dark brown at > 10 ppm inorganic Se and at 20 ppm when organic Se was provided. Bile Se increased as dietary Se level increased (P < 0.01). These results suggest that dietary Se from inorganic or organic sources was toxic at > or = 5 ppm Se, but subsequent selenosis effects were more severe and occurred sooner when sodium selenite was the Se source.  相似文献   

7.
To investigate the effects of supplemental Se on the transfer of Se to nursing pigs when sows are fed diets containing a Se level above the NRC recommendation (0.15 ppm), sows were fed diets containing no supplemental Se or supplemental (0.3 ppm) Se from sodium selenite or Se yeast. A nonSe-fortified corn-soybean meal basal diet with a high endogenous Se content served as the negative control (0.20 to 0.23 ppm Se). Fifty-two sows were fed diets from 60 d prepartum until 14 d of lactation. Six sows per treatment were bled at 60 and 30 d prepartum, at farrowing, and at 14 d postpartum to measure serum Se concentrations. Colostrum was collected within 12 h postpartum, and milk was collected at 14 d of lactation. Blood was obtained from 3 pigs each from 12 litters per treatment at birth and at weaning (d 14), and pooled serum was analyzed for Se and immunoglobulin G concentrations and glutathione peroxidase activity. Regardless of treatment, serum Se in sows declined throughout gestation and gradually increased during lactation. Sows fed Se yeast tended (P < 0.06) to have greater serum Se at farrowing than sows fed unsupplemented diets. Colostrum and milk (d 14) Se concentrations increased (P < 0.01) when sows were fed Se from yeast but not from sodium selenite. At birth, serum Se was increased (P < 0.01) for pigs whose dams were fed Se yeast compared with pigs from sows fed the basal diet. At 14 d of age, there was no difference in serum Se concentration of pigs from dams fed any of the treatments. Pig serum immunoglobulin G concentrations and glutathione peroxidase-1 activity were unaffected by dietary Se source. Supplementation of gestating and lactating sow diets with Se (0.3 ppm) from an organic or inorganic source reduced the number of stillbirths per litter. However, only pigs born to sows fed organic Se (Se yeast) had greater serum Se at birth. Organic Se increased Se concentration of colostrum and 14-d milk to a greater degree than inorganic Se.  相似文献   

8.
A 2 x 3 factorial experiment in a randomized complete block design was conducted using a total of 180 weanling pigs in five replicates. The study evaluated the efficacy of two dietary vitamin E sources (D-alpha-tocopherol, DL-alpha-tocopheryl acetate) added at three dietary levels (16, 48, 96 IU/kg) during a 35-d postweaning trial. Pigs within each treatment were fed two similarly fortified vitamin E diets in sequence; the first contained 40% milk products and was fed to 14 d, and the second contained 20% milk product and 5% fat and was provided from 15 to 35 d postweaning. Five pigs per pen per replicate were bled weekly for serum analysis of alpha-tocopherol, Se, cholesterol, triglyceride, and glutathione peroxidase (GSH-Px) activity. At the end of the trial, one pig per pen was randomly selected and killed with liver, loin, lung, and heart excised and frozen for tocopherol analysis. Postweaning gains, feed intakes, and efficiencies were similar between the two vitamin E sources and at the various dietary levels. Serum tocopherol concentrations were consistently higher when D-alpha-tocopherol was provided. Vitamin E sources and levels had no effect nor did they influence weekly serum Se, cholesterol, or triglyceride concentrations or GSH-Px activity. A serum and tissue interaction (P less than .05) response occurred between dietary vitamin E source x level with alpha-tocopherol concentrations increasing linearly (P less than .01) as dietary vitamin E level increased, but at a higher rate when D-alpha-tocopherol than when DL-alpha-tocopheryl acetate as fed.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

9.
Sugarcane molasses is a widely used animal feed by-product, but is concentrated in S (approximately 1%, DM basis) and has been shown to reduce the Cu status of cattle. Dietary S may also antagonize Se; therefore, two 90-d studies were conducted with forage-fed, yearling steers (12 pens; 2 steers/pen for each study) to investigate the impact of molasses supplementation on measures of Se status. In Exp. 1, steers were assigned isonitrogenous supplements with equivalent amounts of TDN from 2 sources (molasses or corn). Supplemental Se was provided (3.0 mg of Se/d; Na selenite) to both treatments. After 90 d of supplementation, steers provided corn diets had greater (P = 0.02) liver Se concentrations and tended (P = 0.07) to have greater ADG compared with steers supplemented with molasses. Irrespective of treatment (P >/= 0.54), plasma Se concentrations decreased (P < 0.001) and plasma glutathione peroxidase activity increased (P < 0.001) from d 0 to 90. In Exp. 2, sources of supplemental Se (2.5 mg/ d), fed within molasses supplements, were compared. Treatments included 1) Na selenite, 2) Se-yeast (Sel-Plex, Alltech, Nicholasville, KY), or 3) no Se (control). Cattle provided supplemental Se, irrespective of source, had greater (P 相似文献   

10.
In cows from 15 dairy herds (n = 210), serum selenium (Se) concentrations ranged from 0.021 to 0.789 microgram/ml, whereas 0.05 to 0.40 microgram/ml is the reported range for adequate serum Se concentrations in cattle. Serum Se concentrations of dairy cattle appeared to follow a geographic distribution pattern. On the basis of herd mean serum Se concentrations, adequate serum Se concentrations were found in cattle from only 1 of 5 herds grazing forage in the geographic area classified as Se deficient for cattle. Adequate mean serum Se concentrations were found in cattle from 4 of 5 herds located in geographic areas described as having variable forage Se concentrations (Se-marginal areas). Of the 10 herds from these 2 areas, there were only 2 herds in which 95% of the cattle had serum Se concentrations in the Se-adequate range (0.05 to 0.40 microgram/ml). In 2 selected neighboring farms in the Se-deficient area, cattle in 1 herd had adequate serum Se concentrations and cattle in the other herd had less than adequate serum Se concentrations (less than 0.05 microgram/ml). Therefore, more cattle are at risk of developing Se-deficiency disease than is commonly believed and forage of neighboring farms may have different Se concentrations. Serum Se concentrations (up to 0.789 microgram/ml) correlated with glutathione peroxidase enzyme activity; this serum Se concentration (0.789 microgram/ml) is approximately 6.2 times higher than previously reported in dairy cattle. Therefore, RBC glutathione peroxidase activity may be useful in determining the diagnosis of chronic Se toxicosis.  相似文献   

11.
本试验旨在研究酵母硒和纳米硒对育肥后期乳鸽生长性能、肉中微量元素含量及血清抗氧化指标的影响。将210只21日龄健康的美国王鸽随机分成7组,每组3个重复,每个重复10只。试验采用2(硒源)×4(硒水平)双因素随机试验设计,饲粮硒源分别为酵母硒和纳米硒,硒添加水平分别为0(对照,饲喂硒含量为0.08 mg/kg的基础饲粮)、0.1、0.3、0.5 mg/kg(以硒计)。预试期3 d,正试期7 d。结果表明:1)各组乳鸽平均日采食量、平均日增重和料重比无显著差异(P0.05)。2)各加硒组乳鸽肉中硒含量均显著高于对照组(P0.05),且随着硒添加水平的升高而增加,硒源和添加水平之间存在显著交互作用(P0.05);与对照组相比,0.1、0.3、0.5 mg/kg硒的酵母硒组肉中硒含量分别显著提高了28.72%、62.09%、106.05%(P0.05),0.1、0.3、0.5 mg/kg硒的纳米硒组分别显著提高了19.83%、26.12%、45.65%(P0.05),且酵母硒组肉中硒的含量显著高于纳米硒组(P0.05)。3)与对照组相比,0.3、0.5 mg/kg硒的酵母硒和纳米硒组乳鸽血清总超氧化物歧化酶、谷胱甘肽过氧化物酶、过氧化氢酶活性及总抗氧化能力均显著提高(P0.05),血清丙二醛含量显著降低(P0.05);与对照组、0.1 mg/kg组相比,0.3、0.5 mg/kg组血清过氧化氢酶活性、总抗氧化能力显著提高(P0.05),血清丙二醛含量显著降低(P0.05)。综上,饲粮中添加酵母硒和纳米硒均能显著增强育肥后期乳鸽血清抗氧化性能,显著提高鸽肉中硒的含量。  相似文献   

12.
The objectives of this 72-wk study were to evaluate and compare the effects of 6 dietary levels of inorganic Se on serum, whole blood, wool, and tissue Se concentrations and to determine the maximum tolerable level of Se for mature ewes during lamb production. Forty-one, 4-yr-old, range-type ewes (57.4 +/- 5.7 kg) were used in a completely randomized design with 6 dietary treatments. Sodium selenite was added to a corn and soybean meal-based diet to provide 0.2 (control), 4, 8, 12, 16, or 20 mg of dietary Se/kg to ewes during lamb production. Serum Se and ewe BW were measured at 4-wk intervals; whole blood Se and wool Se were measured every 12 wk; and samples of brain, diaphragm, heart, hoof, kidney, liver, and psoas major were collected at the termination of the experiment. Dietary Se did not affect ewe BW during the study (P = 0.69), and there was no treatment x time interaction. Serum Se increased linearly as dietary Se level increased (P < 0.001) and responded cubically (P = 0.02) over time. Selenium in whole blood increased linearly (P < 0.001) as supplemental Se increased. Wool Se increased linearly (P < 0.001) as dietary Se increased, and the response over time was quadratic (P < 0.001). Brain, diaphragm, heart, and psoas major Se increased (P < 0.05) linearly as dietary Se increased, liver Se responded quadratically (P < 0.05), and hoof and kidney Se increased cubicically (P < 0.05) as supplemental Se increased. In general, serum, whole blood, and tissue Se concentrations of ewes receiving 12, 16, or 20 mg of dietary Se/kg were greater (P < 0.05) than those of controls and ewes receiving less dietary Se. Although they were elevated in ewes receiving increased dietary Se, at no time did serum, whole blood, or wool Se concentrations reach levels previously reported as toxic, nor were clinical signs of Se toxicosis observed. Histopathological evaluation of liver, kidney, diaphragm, heart, and psoas major did not reveal evidence of Se toxicosis in ewes at any dietary Se level. Ewes under our experimental conditions and during the stresses of production were able to tolerate up to 20 mg of dietary Se/kg as sodium selenite for 72 wk. These findings suggest that the maximum tolerable level of inorganic Se for sheep is much greater than 2 mg/kg as was suggested previously. Experiments of longer duration and utilizing greater dietary Se concentrations are necessary to clearly define the maximum tolerable level.  相似文献   

13.
1. The effect of dietary vitamin E, selenium (Se) and their different combinations on body weight gain, food consumption, food conversion efficiency, leukocyte migration inhibition and antibody production was determined in broilers. 2. Chicks were fed on maize-soya bean based diets with concentrations of supplemental vitamin E varying from 0 to 300 IU/kg and selenium concentrations varying from 0 to 1 mg/kg either alone or in combination from 1 to 42 d of age. 3. The chicks were immunised for Newcastle Disease Virus (NDV) vaccine at 21 d. Per cent leukocyte migration inhibition (LMI) was studied on 42 d. Antibodies to NDV in serum were determined at 10 and 21 d post immunisation (PI). 4. Chicks receiving Se, 1 mg/kg and vitamin E 300 IU/kg had significantly higher cellular immune responses in terms of per cent LMI. 5. Maximum body weight gain and best efficiency of food utilisation were obtained in chicks fed diets containing 0.50 mg/kg Se and 300 IU/kg vitamin E. 6. Significantly higher antibody titres (HI and ELISA) at 10 d PI were attributed to 0.06 mg/kg and 150 IU/kg Se and vitamin E, respectively. 7. These data suggest that optimum growth and immune response may be achieved at supplemental level of Se of 0.06 mg/kg and vitamin E at 150 IU/kg. The vitamin E level is higher than that recommended by NRC (1984, 1994).  相似文献   

14.
The objective of this study was to determine the effect of evaporative cooling and dietary supplemental Zn source on blood metabolites, insulin and mineral concentrations, and milk mineral concentrations following intramammary lipopolysaccharide (LPS) infusion. Seventy-two multiparous Holstein cows were assigned to one of four treatments with a 2 × 2 factorial arrangement. Treatments included two environments: with or without evaporative cooling using fans and misters over the freestall and feedbunk, and two dietary sources of supplemental Zn: 75 mg/kg of dry matter (DM) supplied by Zn hydroxychloride (inorganic Zn; IOZ) or Zn hydroxychloride (35 mg of Zn/kg of DM) + Zn–Met complex (ZMC; 40 mg of Zn/kg of DM). A subset of cows (n = 16; 263 ± 63 d in milk) was infused with 10 μg of LPS or a saline control in the left or right rear quarters on day 34 of the environmental treatment. Individual milk samples collected from LPS-infused quarters at −4, 0, 6, 12, 24, 48, 72, 96, and 144 h relative to infusion were analyzed for minerals. Blood samples were collected at the same time with an additional sample collected at 3 h post-infusion to analyze glucose, nonesterified fatty acids (NEFA), insulin, and minerals. Cooling by time interactions (P ≤ 0.07) were observed for plasma glucose, NEFA, and serum insulin. Compared with cooled cows, non-cooled cows had lower concentrations of plasma glucose except at 3 h following intramammary LPS infusion, greater serum insulin at 3 and 12 h, and lower plasma NEFA at 24 and 48 h after infusion. Relative to cooled cows, non-cooled cows tended (P = 0.07) to have lower serum K concentration and had lower (P < 0.01) serum Zn 6 h following infusion (cooling by time interaction: P < 0.01). Relative to ZMC cows, IOZ cows had greater (P ≤ 0.09) concentrations of plasma Se, skim milk Na and Se, and skim milk Na to K ratio. Regardless of treatment, intramammary LPS infusion reduced (P < 0.01) serum or plasma concentrations of Ca, Mg, Zn, Fe, and Se, but increased (P < 0.01) their concentration in skim milk. In conclusion, deprivation of cooling resulted in more rapid and prolonged insulin release and influenced the systemic and mammary mineral metabolism during mammary inflammation induced by LPS of lactating dairy cows. Dietary supplementation of Zn–Met complex reduced blood and milk Se concentrations compared with cows fed Zn from an inorganic source.  相似文献   

15.
A study was conducted to evaluate the short-term effects of feeding two dietary Se sources at various Se levels on the transfer of Se to the dam's milk and nursing pig. Six dietary treatments were arranged in a 2 x 2 factorial arrangement with two additional treatments in a randomized complete block designed experiment. Inorganic (sodium selenite) or organic (Se-enriched yeast) Se sources were added to the diet at .15 or .30 ppm Se. A non-Se-fortified corn-soybean meal basal diet served as a negative control, and a sixth group was fed .15 ppm Se from both inorganic and organic Se sources. A total of 43 sows were fed their treatment diets at 2.2 kg/d from 6 d prepartum to parturition and at full feed through a 14-d lactation period. Ten sows were initially bled at 6 d prepartum, and three sows and three pigs from their litters were bled at 7 and 14 d postpartum. Serum was analyzed for its Se concentration and glutathione peroxidase (GSH-Px) activity. Colostrum was collected within 12 h postpartum and milk at 7 and 14 d of lactation. When the basal diet was fed, sow serum GSH-Px activity declined from 6 d prepartum and remained low throughout lactation. When dietary Se levels increased, sow serum Se concentration and serum GSH-Px activity increased (P < .05) at both 7 and 14 d postpartum. The short-term feeding of either Se source at .15 or .30 ppm Se did not affect colostrum Se content when inorganic Se was fed, but it was increased when organic Se was provided. This resulted in a significant Se source x Se level interaction (P < .01). Milk Se at 7 and 14 d postpartum was 2.5 to 3 times higher when the organic Se source was provided and resulted in a significant Se source x Se level interaction (P < .05). When the combination of inorganic and organic Se was fed at .15 ppm Se, colostrum and milk Se contents were similar to those of sows fed .15 ppm Se from the organic Se source. Pig serum GSH-Px activity was not affected at 7 and 14 d of age by dietary Se level or Se source fed to the sow, but serum Se increased (P < .05) as dietary Se level increased, particularly when sows had been fed organic Se. The results demonstrated that organic Se increased milk Se content more than did inorganic Se and increased the nursing pig's serum Se. These results indicate that inorganic Se was more biologically available for sow serum GSH-Px activity, but organic Se was more effectively incorporated into milk.  相似文献   

16.
This research evaluated the efficacy of inorganic and organic Se sources for growing-finishing pigs, as measured by performance and various tissue, serum, carcass, and loin quality traits. A total of 351 crossbred pigs were allotted at an average BW of 20.4 kg to six replicates of a 2x4 factorial experiment in a randomized complete block design. Pigs were fed diets containing Se-enriched yeast (organic) or sodium selenite (inorganic), each at .05, .10, .20, or .30 mg Se/kg diet. A non-Se-fortified basal diet was a ninth treatment group. Five pigs per pen were bled initially and at 30-d intervals with serum analyzed for Se and glutathione peroxidase (GSH-Px) activity. At 55 kg BW, one pig per pen from each of three replicates was killed, and tissues were collected for Se analysis. At 105 kg BW, the remaining pigs in the three replicates were killed, carcass measurements were collected, tissues were analyzed for Se, and loin quality was evaluated for pH, drip loss, and lightness. No performance or carcass measurement benefit resulted from either Se source or dietary Se levels. Pigs had a lower serum Se concentration and GSH-Px activity when the basal diet was fed, but both increased as dietary Se level increased (P<.01). Serum GSH-Px activities were increased by pig age and reached a plateau when the diet contained approximately .10 mg Se/kg (P<.01) at d 30, and 60 of the trial, and at .05 mg Se/kg diet at d 90 of the trial. The organic Se group fed .05 and .10 mg Se/kg had serum GSH-Px activities that tended to be lower than those of pigs fed the inorganic Se source, but GSH-Px activities in both groups were similar at higher Se levels. Tissue Se contents increased linearly as the dietary Se level increased, but the increase was markedly higher when organic Se was fed, resulting in an interaction (P<.01) response. Loin drip loss, pH, and lightness were unaffected (P>.15) by organic Se source or level, but there was a trend for a higher drip loss (P = .11) and a linear (P<.01) increase in loin paleness when the inorganic Se level increased. These results indicate that neither Se source nor Se level had an effect on pig performance or carcass measurements, but organic Se source increased tissue Se concentrations. Inorganic Se may, however, have a detrimental effect on loin quality, as reflected by higher drip loss and a paler color. Using serum GSH-Px activity as the measurement criterion, the supplemental dietary Se requirement did not seem to exceed .10 and .05 mg Se/kg diet for the growing and finishing phases, respectively, when added to a basal diet containing .06 mg Se/kg.  相似文献   

17.
1. An investigation was carried out into the effects of dietary α-tocopherol (α-T) concentration and source of supplemental oil on performance, activity of anti-oxidative enzymes and some immune responses in broilers from day-old to 41 d of age. 2. Three dietary concentrations of α-T (10, 50 and 100 mg/kg) with three sources of supplemental oil (sunflower - SFO, palm - PMO and safflower - SAO) were provided using a 3 × 3 experimental design. 3. Body weight gain and food conversion efficiency were not affected by either interaction or concentrations of α-T and sources of oil in diet. 4. Concentrations of total protein, globulin, triglycerides and cholesterol in sera increased significantly with dietary α-T concentration irrespective of the source of oil. Significantly higher concentration of serum albumin was evident in broilers fed on the SFO-based diet and the concentration of globulin was higher in groups fed on those diets containing PMO and SAO. 5. The lipid peroxidation (LP), measured as MDA release, decreased with the concentration of α-T in a dose-related manner with SFO- and SAO-based diets, although not with the PMO-based diet. With different oil sources, LP was significantly lower with the PMO-based diet compared to the others. Activities of glutathione peroxidase and RBC catalase increased and heterophil: lymphocyte ratio was reduced with concentration of α-T for each source of oil tested. 6. Assays for humoral and cell-mediated immune responses indicated no effect of the source of dietary supplemental oil or interaction, although an increasing concentration of dietary α-T improved cell-mediated immune responses. 7. It is concluded that sunflower oil, palm oil and safflower oil can be used as sources of oil for broiler diets without having any effect on performance, immune responses or the activity of anti-oxidizing enzymes. Higher concentrations of dietary α-tocopherol (50 or 100 mg/kg) reduced lipid peroxidation activity and enhanced activities of anti-oxidative enzymes, they also improved the cell-mediated immune responses in commercial broilers.  相似文献   

18.
A 2 x 3 factorial experiment conducted in three replicates of a randomized complete block design compared the effects of calcium selenite and sodium selenite at three different levels of Se (.3, 5, or 15 ppm) in the diets of growing swine on performance and tissue Se concentrations. Ninety pigs averaging 12.5 kg of BW were given ad libitum access to corn-soybean meal diets fortified with one of the treatment Se sources and dietary levels for a 35-d experimental period. Growth and feed intake were similar in pigs fed .3 and 5 ppm of Se but were lower (P less than .01) in those fed 15 ppm from either Se source. Serum Se increased (P less than .01) as dietary Se level increased with no difference between Se sources at each dietary Se level. Liver, kidney, and longissimus muscle Se concentrations increased (P less than .01) as the dietary level of Se increased and were similar when either Se sources was provided. These results indicate that calcium selenite was as effective as sodium selenite using the measurement criteria of growth, serum, and tissue Se concentrations and glutathione peroxidase activities of growing swine when fed at approved, marginally toxic, and toxic dietary Se levels.  相似文献   

19.
Semen characteristics in boars fed organic or inorganic sources of Se were assessed in 3 experiments. Crossbred boars were randomly assigned at weaning to 1 of 3 dietary treatments: I) basal diets with no supplemental Se (control), II) basal diets with 0.3 mg/kg of supplemental Se from an organic source (Sel-Plex, Alltech Inc., Nicholasville, KY), and III) basal diets supplemented with 0.3 mg/kg of supplemental Se from sodium selenite (Premium Selenium 270, North American Nutrition Co. Inc., Lewisburg, OH). For Exp. 1, semen was collected from boars (n = 10/dietary treatment) on 5 consecutive days at 15 mo of age. Effects of treatment × day were detected for the proportions of progressively motile (P = 0.02) and rapidly moving (P = 0.03) spermatozoa, and measures of sperm velocity, including path velocity of the smoothed cell path (P = 0.05) and average velocity measured in a straight line from the beginning to the end of the track (P = 0.05). Negative effects of day of semen collection on sperm motility were least pronounced in boars fed Sel-Plex. Experiment 2 was conducted when boars were 17 mo of age, and semen was collected (n = 10 boars/dietary treatment), diluted in commercially available extenders, and stored at 18°C for 9 d. Effects of treatment × day were detected for percentages of motile (P = 0.01) and static (P = 0.01) spermatozoa, amplitude of lateral head displacement (P = 0.02), frequency with which the sperm track crossed the sperm path (P = 0.04), straightness (P = 0.01), and average size of all sperm heads (P = 0.03). In general, sperm cells from boars fed Sel-Plex were better able to maintain motility during liquid storage compared with boars fed sodium selenite. For Exp. 3, semen was collected from boars (n = 6/dietary treatment) at 23 mo of age, and spermatozoa were evaluated at d 1 and 8 after semen collection using in vitro fertilization procedures. There was a tendency for an effect (P = 0.11) of dietary treatment on fertilization rate with Sel-Plex-fed boars having the greatest value (70.7%). The results of this study suggest that there are positive effects of dietary supplementation with Sel-Plex on boar semen characteristics and that organic Se supplementation may help ameliorate the negative effects of semen storage on characteristics of sperm motility.  相似文献   

20.
Bulk tank milk selenium (Se) concentration was compared with mean serum Se concentration in 15 herds and was found to be an accurate reflection of the herd Se status. The Se status of 109 Prince Edward Island (PEI) dairy herds was monitored for 1 year using bulk tank milk Se concentration. Fifty-nine percent of the herds surveyed were, at some point, found to be marginal or deficient in Se, putting them at risk of disease and suboptimal production. The periods of greatest risk of deficiency were fall and winter, at which time 5% and 4%, respectively, of herds sampled fell in the range considered truly deficient in Se. Herds in which Se supplementation was provided in the form of a commercial dairy concentrate were over 4 times more likely to be Se-adequate than herds not using this method, and adjusted average daily milk yield was 7.6% greater in herds determined to be Se-adequate when compared with Se-marginal herds. We conclude that many dairy producers in PEI are providing insufficient supplementary Se in the ration to meet the recommended Se intake for lactating cows.  相似文献   

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