Effect of selenium supplementation and source on the selenium status of horses

This study was conducted to determine the effect of Se supplementation and source on the Se status of horses. Eighteen 18-mo-old nonexercised horses were randomly assigned within sex to 1 of 3 treatments: 1) control (CTRL, no supplemental Se, 0.15 mg of Se/kg of total diet DM); 2) inorganic Se (INORG, CTRL + 0.45 mg of Se/kg of total diet DM from NaSeO3); or organic Se [ORG, CTRL + 0.45 mg of Se/kg of total diet DM from zinc-L-selenomethionine (Availa Se, Zinpro, Corp., Eden Prairie, MN)]. Horses were acclimated to the CTRL diet (7.1 kg of DM alfalfa hay and 1.2 kg of DM concentrate per horse daily) for 28 d. After the acclimation period, the appropriate treatment was top-dressed on the individually fed concentrate for 56 d. Jugular venous blood samples were collected on d 0, 28, and 56. Middle gluteal muscle biopsies were collected on d 0 and 56. Muscle and plasma were analyzed for Se concentrations. Glutathione peroxidase activity was measured in muscle (M GPx-1), plasma (P GPx-3), and red blood cells (RBC GPx-1). Data were analyzed as a repeated measures design. Mean plasma Se concentration on d 28 and 56 was greater (P < 0.05) for Se-supplemented horses compared with CTRL horses, and tended (P < 0.1) to be greater in ORG vs. INORG on d 28. Mean muscle Se concentration and P GPx-3 activities increased (P < 0.05) from d 0 to 56 but were not affected by treatment. Mean RBC GPx-1 activity tended to be greater (P < 0.1) in ORG than INORG or CTRL horses on d 28, and tended to be greater (P < 0.1) for INORG compared with ORG horses on d 56. Mean RBC GPx-1 activity of INORG and ORG horses was not different from that of CTRL on d 56. Mean M GPx-1 activity decreased (P < 0.01) from d 0 to 56. In conclusion, zinc-L-selenomethionine was more effective than NaSeO3 at increasing plasma Se concentration from d 0 to 28; however, both supplemental Se sources had a similar effect by d 56. No difference in Se status due to Se supplementation or source could be detected over a 56-d supplementation period by monitoring middle gluteal muscle Se, M GPx-1, or P GPx-3. Results for RBC GPx-1 also were inconclusive relative to the effect of Se supplementation and source.     

Effects of nitrogen and energy source on nutrient digestibility in the young pig

Dried whole whey, lard or dried skim milk was added to a corn-soybean meal basal diet to determine the effect on apparent nitrogen (ND), energy (ED) and dry matter digestibility (DMD) in pigs weaned at 28 d. Four groups of four littermate barrows were allotted to the experimental diets and placed in individual metabolism pens for 12 d (3 d adjustment and three collection periods of 3 d each) after weaning. The study was a 4 X 3 factorial with diet and period as main effects. Addition of dried skim milk or dried whey to the diet resulted in higher values (P less than .05) for DMD and ED as compared with the basal or corn-soy and lard diet. Pigs fed added dried skim milk had improved (P less than .05) ND over pigs on other dietary treatments. All nutrient digestibility coefficients increased (P less than .05) from period 1 to period 2, and ND increased (P less than .05) from period 2 to 3. It was concluded that the young pig requires at least 6 to 9 d after weaning at 28 d to adjust to typical corn-soybean meal starter diets.     

Effect of dietary selenium source, level, and pig hair color on various selenium indices

The first experiment evaluated the effects of feeding various levels of Se, two Se sources, and hair color on selenosis responses in growing-finishing pigs. The study conducted in two replicates was a 2 x 6 x 2 factorial arrangement in a split-plot design. Sodium selenite and Se-enriched yeast added at 0.3, 1, 3, 5, 7, and 10 ppm Se served as the main plot and pig hair color as the subplot. A total of 96 crossbred pigs were allotted and fed their treatment diets for a 12-wk period. White and dark (red or black) hair samples were collected from the dorsal-midline at the 4-, 8-, and 12-wk periods from one pig of each hair color from each treatment pen. Lower pig weights (P < 0.10) and daily gains (P < 0.05) occurred as dietary Se level increased when pigs were fed either Se source. Selenosis responses were somewhat more severe, when the inorganic Se source was fed. Alopecia and hoof separation were encountered after the 8-wk period when pigs were fed inorganic rather than organic Se. Plasma Se increased as dietary level increased (P < 0.01), when organic Se was provided (P < 0.01), and was higher (P < 0.05) when pigs were white-haired. A time x hair color x dietary Se level interaction (P < 0.05) occurred, in which hair Se concentration was higher in dark- than in white-colored pigs and increased as dietary Se level increased as the experiment progressed. The correlation coefficient between dietary Se level and hair Se concentration averaged 0.90 (P < 0.01). Cysteine was the amino acid in the highest concentration in hair, but this and other amino acids were not affected by Se level, Se source, or hair color. A second experiment was a 3 x 6 factorial arrangement in a split-plot design with three 9-mo-old gilts from each of the Yorkshire, Duroc, and Hampshire breeds to determine whether hair Se concentration differed by body location and breed. Hair samples were collected from the shoulder, back, rump, front-leg, belly, and hind-leg areas. Hair Se concentration was higher in red- and white-haired pigs and lower in black-haired gilts (P < 0.01). Higher hair Se concentrations (P < 0.05) occurred from the lower than from the upper body areas. Our results suggest that selenosis occurs at dietary levels > 5 ppm and that white-haired pigs exhibit alopecia sooner than dark-haired pigs. No difference in hair Se concentration occurred when diets were < 1 ppm Se, but as dietary Se level increased dark-haired pigs retained more Se in their hair than white-haired pigs.     

Effects of selenium source on measures of selenium status and immune function in horses

The effects of selenium (Se) supplementation and source on equine immune function have not been extensively studied. This study examined the effects of oral Se supplementation and Se source on aspects of innate and adaptive immunity in horses. Fifteen horses were assigned to 1 of 3 groups (5 horses/group): control, inorganic Se (sodium selenite), organic Se (Se yeast). Immune function tests performed included: lymphocyte proliferation in response to mitogen concanavalin A, neutrophil phagocytosis, antibody production after rabies vaccination, relative cytokine gene expression in stimulated lymphocytes [interferon gamma (IFNγ), interleukin (IL)-2, IL-5, IL-10, tumor necrosis factor alpha (TNFα)], and neutrophils (IL-1, IL-6, IL-8, IL-12, TNFα). Plasma, red blood cell Se, and blood glutathione peroxidase activity were measured. Plasma and red blood cell Se were highest in horses in the organic Se group, compared with that of inorganic Se or control groups. Organic Se supplementation increased the relative lymphocyte expression of IL-5, compared with inorganic Se or no Se. Selenium supplementation increased relative neutrophil expression of IL-1 and IL-8. Other measures of immune function were unaffected. Dietary Se content and source appear to influence immune function in horses, including alterations in lymphocyte expression of IL-5, and neutrophil expression of IL-1 and IL-8.     

Effects of selenium and copper supplementation on the growth of beef steers

During the grazing seasons of 1978 and 1979, 126 Hereford cross Friesian and 25 Charolais cross Friesian steers were used in controlled trials of the effects of injecting them with copper and, or, selenium. In both seasons the unsupplemented steers had low blood concentrations of copper, selenium and glutathione peroxidase, whereas the supplemented steers maintained their serum copper concentrations within the normal range and had significantly higher whole blood concentrations of selenium and glutathione peroxidase than the unsupplemented animals. Supplementing the steers with 400 mg copper during 1978 increased their growth rate by 0.032 kg/day and supplementing them with 200 mg copper during 1979 increased it by 0.080 kg/day. Supplementing the steers in each year with two doses of selenium, each of 0.15 mg selenium/kg bodyweight, increased their growth rate by 0.041 kg/day in 1978 and by 0.060 kg/day in 1979. There was no interaction between the selenium and copper treatments and the total increases in liveweight gains due to both supplements were around 11 kg in 1978 and 16 kg in 1979.     

Effects of selenium and vitamin E supplementation on selenium distribution and meat quality of pigs

Abstract

The study was conducted on 60 pigs kept in individual pens. The animals were allocated to four groups. The growing-finishing pigs from the control group were fed with basic feed containing 0.3 mg selenium (Se) derived from Na₂SeO₃ kg^?1 and 60 mg of dl-α-tocopheryl acetate kg^?1. The remaining three groups were differentiated by adding 0.2 mg kg^?1 Se-enriched yeast (Saccharomyces cerevisiae) and/or 60 mg vitamin E to feed (grower and finisher). Our results show that the addition of organic Se to inorganic Se commonly used in pig feed caused a significant increase in hepatic Se and muscle. This indicates the possibility of using these products as functional foods to improve Se status in humans residing within regions which are deficient in this trace element. We found no beneficial effect of supplementation with vitamin E and Se on the quality of the meat.     

Effects of dietary borate and aluminate on riboflavin metabolism in the breeding hen

Breeding hens were used to investigate the effects of aluminate and borate ingestion on riboflavin metabolism. Groups of six hens were fed on either a control diet, or the control diet plus 15 g kg-1 of either sodium metaborate or sodium meta-aluminate. All diets contained 6 mg kg-1 riboflavin. Daily egg production per hen in the borate group had mean values of 0.71, 0.21 and 0.02 for the three weeks of the study. The values were 0.91, 0.91, 0.86 and 0.86, 0.74, 0.89 for the control and aluminate groups, respectively. Fertility (fertile eggs per 100 set) and hatchability (live chicks per 100 fertile eggs) were both nil in the borate-treated hens, compared with 57 and 95 and 59 and 100 for the control and aluminate-treated hens, respectively. Fluorimetric analysis of blood plasma, egg yolk and albumen showed that the riboflavin contents of all tissues were greatly reduced in the borate-treated hens. Borate ingestion can therefore induce a severe riboflavin deficiency in the hen, but aluminium, a more universal contaminant of food or water, did not impair riboflavin metabolism when fed as aluminate.     

Effects of pre- or postpartum selenium supplementation on selenium status in beef cows and their calves

The effect of Se supplementation before or after calving on Se status in deficient cows and their calves was studied using 72 beef cows in two experiments. In Exp. 1, cows calving in February or March 1997 were supplemented orally for 15 d in late pregnancy with 13.0, 32.5, or 45.5 mg of Se/d as sodium selenite. Glutathione peroxidase (GSH-Px) activities were measured in red blood cells (RBC) or plasma of cows and calves at d 15 and between d 17 and 88 after calving. In Exp. 2, cows calving in January 1997 were supplemented orally with .0, 13.0, or 32.5 mg of Se/d for 15 d postpartum, and calves were injected with 1.38 mg of Se when 2 d old and at an average age of 49 d. The GSH-Px activities were measured in 30-d-old calves and in cows and calves between d 77 and 115 after calving. In both experiments, Se supplementation resulted in adequate Se status for the dams. The increase in RBC GSH-Px activity was faster with 45.5 mg of Se/d, and GSH-Px activities remained high for up to 98 d after the end of supplementation. The improvement in Se status in calves as a result of maternal supplementation was greater in Exp. 1 than in Exp. 2, suggesting that the placental transfer of Se is more efficient than milk transfer. Prepartum oral Se supplementation of deficient beef cows with 13.0 mg of Se/d for 15 d allowed adequate Se status of dams and calves, and 45.5 mg of Se/d resulted in a faster improvement of Se status. Parenteral administration of 1.38 mg of Se to newborn calves did not sustain normal Se status in calves issued from deficient cows.     

Effects of dietary supplementation with an organic source of selenium on characteristics of semen quality and in vitro fertility in boars

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.     

Effects of selenium supplementation on plasma progesterone concentrations in pregnant heifers

It is known that selenium (Se) has various functions in animals. Many investigations on the biochemical and physiological effects of Se have been previously reported; however, the detailed function of Se in reproduction is not yet clear. We proposed the possibility that Se plays a notable role in progesterone production. The aim of this study was to clarify the effects of Se supplementation on progesterone levels of pregnant Holstein heifers. Eight Holstein heifers (?Se) were fed basal diet (containing 0.022 ppm of Se) throughout the experiment. While a 0.3 ppm diet of Se (sodium selenite) was fed to another seven animals (+Se) with basal diet. Blood sampling was carried out every week. Plasma Se concentrations were higher in Se‐supplemented cows compared with controls (?Se) (P < 0.01) throughout the experiment. Se supplementation increased plasma progesterone in the 29–39 weeks of pregnancy from 4.98 ± 0.64 to 6.86 ± 0.49 ng/mL on average (P < 0.05). The present findings suggest that Se contributes to maintaining the function of the corpus luteum and/or placenta in the latter period of pregnancy.     

在猪饲料中添加硒对屠宰价值、猪肉理化性状和感官特性的影响

本研究的目的是为了评价有机硒和无机硒在猪饲料中作为添加剂的可同化性。试验检测了这两种不同形式的硒对屠宰价值、理化性状和肉质感官的影响(试验I),并尝试性地测定硒在试验性育肥猪体内的含量(试验II)。试验I的试验对象为20头杂交猪,基因型为(波兰大白猪×波兰长白猪)×杜洛克(Polish Large White×Polish Landrace)×Duroc;PLW×PL×Duroc);试验II则是以45头杂交育肥猪的最长肌和半膜肌作为检测样品,基因型与试验I相同。试验结果表明,在猪日常饮食中添加硒不影响屠宰性能、肉的品质和感官特性以及大部分的理化性状,并且发现硒对猪肉颜色的改变没有显著效果。经检测,有机硒实验组的育肥猪的猪肉保水能力(water holding capacity,WHC)降低,而在无机硒实验组的育肥猪的半膜肌内硒的含量最高。     

Effect of selenium, vitamin E and riboflavin supplementation of the feed on the humoral and cell-mediated immune responses of growing pigs

The feed of weaned piglets of Hungarian Large White X Duroc and Dutch Landrace X Duroc genotype was supplemented with 0.5 mg selenium, 50, 100 or 150 mg vitamin E, and 2.5 or 5 mg riboflavin per kg. Feed supplementation enhanced the cytotoxic reaction and elevated the antibody titres produced against purified horse gamma globulin antigen. However, as compared to the control the differences were not significant. Feed supplementation exerted a beneficial, though varying, influence on the indices of cell-mediated immunity. The proportion of rosette-forming cells and blastogenic transformation induced by specific (horse globulin) and nonspecific (phytohaemagglutinin, PHA) mitogens underwent the most expressed and most significant increase in pigs fed 5 mg selenium, 100 mg vitamin E and 5 mg riboflavin per kg of feed. On the other hand, feed supplementation failed to enhance the responsiveness to intradermal PHA (type IV allergic reaction).     

Effects of oral selenium supplementation on mastitis markers and pathogens in Estonian cows

The effects of selenium supplementation on mastitis parameters in milk and on glutathione peroxidase (GPx) levels in blood were evaluated. Fifty-five Estonian dairy cows were allocated to selenium-supplemented (n=39) and nonsupplemented (n=16) groups. The supplemented group received 0.2 ppm organic selenium in the form of selenium yeast in their diet daily for 8 weeks. The nonsupplemented cows received their standard diet with no selenium supplementation. Mastitis parameters (i.e., bacteriologic findings and somatic cell count, N-acetyl-beta-D-glucosaminidase, and bovine serum albumin concentration) and GPx levels were monitored. The increase in the activity of GPx was significantly (P<.001) greater in selenium-supplemented cows than in nonsupplemented ones. Milk samples from each quarter were examined before and 8 weeks after initiation of the study. The proportion of quarters still pathogen-free after 8 weeks was significantly (P<.01; odds ratio [OR]=9.7) higher in selenium-supplemented cows than in nonsupplemented cows. However, when quarters milk-tested as pathogen-infected at the start of the study were reexamined after 8 weeks, there was no significant (P=.14; OR 3.6) difference in the proportion of pathogen-free quarters between selenium-supplemented cows and nonsupplemented cows. Differential positive rate (Youden's index) revealed that individual quarters were more prone to be infected by pathogens when the blood GPx activities in cows were below the cutoff value of 3.3 microkat/g hemoglobin than when GPx activity was above this value. It was concluded that selenium supplementation in cows with low GPx activity seems to support udder defense mechanisms that favor reduction of the incidence of new mastitis cases.     

日粮核黄素添加水平对新扬州仔鸡免疫功能的影响

选用288只体重相近1日龄新扬州雏鸡,随机分成4组,每组3个重复,分别饲喂4种不同核黄素添加量(0、3.6、7.2 mg/kg和14.4 mg/kg)日粮,探讨核黄素添加水平对新扬州仔鸡免疫功能的影响。结果表明:(1)新扬州鸡的胸腺、脾脏和法氏囊重量均随日粮核黄素添加量增加呈现递增趋势,但各处理组作用效果不相同。(2)新扬州仔鸡外周血液白细胞总数、淋巴细胞总数及其百分比均与核黄素添加量增加呈递增趋势,但各处理组间差异均不显著(P>0.05)。(3)各核黄素添加组均能提高新城疫抗体水平,但添加7.2 mg/kg和14.4 mg/kg核黄素显著或极显著影响抗体水平。本研究认为,日粮中添加适量核黄素能够提高家禽免疫功能。     

不同硒源对蛋鸡生产性能和硒沉积的影响

文章旨在研究日粮添加不同硒源及不同水平对蛋鸡生产性能和鸡蛋中硒沉积量的影响。试验选择产蛋率一致的海兰褐壳蛋鸡720只,随机分为5组,每组6个重复,每个重复24只鸡。试验共设计5种日粮,对照组饲喂基础日粮(不添加硒),处理组分别在基础日粮中添加2个水平的无机硒(0.4和0.8mg/kg硒,亚硒酸钠)以及2个水平的酵母硒(0.4和0.8mg/kg硒),试验共进行16周。结果发现,无论日粮添加酵母硒还是无机硒,随着硒添加水平的升高,蛋鸡生产性能均无显著影响(P>0.05)。从第9周到试验结束,0.4mg/kg无机硒和0.8mg/kg酵母硒组较对照组和0.8mg/kg无机硒组显著提高了蛋鸡的产蛋率(P<0.05)。试验第9周开始,对照组、0.8mg/kg无机硒组和0.4mg/kg酵母硒组产蛋率显著降低(P<0.05)。随着日粮无机硒或酵母硒添加水平的升高,鸡蛋中硒的沉积量显著线性增加(P<0.05)。从第4周开始到试验结束,无机硒或酵母硒组较对照组均显著提高了鸡蛋中硒含量(P<0.05)。在同一硒添加水平及同一时间下,酵母硒较无机硒显著提高了鸡蛋硒含量(P<0.05),随着试验时间的增加,对照组鸡蛋硒含量显著降低(P<0.05)。因此,在本试验条件下,日粮硒的来源和添加水平直接影响鸡蛋硒沉积量,酵母硒较无机硒显著提高了鸡蛋硒沉积量。日粮中酵母硒的添加量可以达到0.8mg/kg,对蛋鸡生产性能无负面影响。     

Effects of supplement type and selenium source on measures of growth and selenium status in yearling beef steers

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   

Effect of inorganic selenium supplementation on selenium retention in postweaning swine

A total of 64 weanling pigs was used in a randomized complete-block experiment to evaluate the efficacy of various inorganic Se levels on weekly Se balance measurements over a 5-wk post-weaning period. Four-week-old weaned pigs were fed a 20% protein, corn-soybean meal diet supplemented with 0, .3, .5 or 1.0 ppm Se from sodium selenite. Eight pigs were allotted by weight, litter and sex to each metabolism crate. A 2-d preliminary period followed by a 5-d collection period was conducted for five weekly periods. Feed intake was provided ad libitum but was similar between dietary Se levels. Fecal Se excretion increased each week and with increasing dietary Se level. Apparent digestibility of Se was relatively constant for each period when inorganic Se was fed, averaging approximately 70%, whereas it ranged between 30 to 40% for pigs fed the basal diet during wk 2 through 5. Urinary Se decreased during the postweaning periods for pigs fed the basal diet, but increased linearly as dietary Se increased during the initial 2-wk postweaning period and then quadratically during wk 3 through 5. There was a net loss of Se from the body when the Se-unsupplemented basal diet was fed during the initial 2 wk postweaning, whereupon, it became positive. Selenium retention in pigs supplemented with inorganic Se increased each week of the trial. When Se retention was expressed in relation to Se intake, the resulting regression was linear (R2 = .99), suggesting that Se retention in the postweaning pig increased in direct proportion to the amount consumed when diets contained up to 1.0 ppm Se.     

Effects of selenium supplementation in cattle on aquatic ecosystems in northern California.

The potential impact on aquatic ecosystems of supplementing the diets of beef cattle with selenium (Se) was studied on 4 northern California ranches. All study sites included an area of concentrated use by cattle that had diets supplemented with Se. In each case, a stream flowed through the site and provided a control sampling area upstream and a treated sampling area downstream. Specimens of water, sediment, algae, aquatic plants, aquatic invertebrates, and fish were analyzed fluorometrically for total Se content. Significant differences in Se concentration were not found between specimens from upstream control areas and those from downstream areas subjected to use by Se-treated cattle. Evidence was not found that Se supplementation in cattle at maximal permitted concentrations caused Se accumulation in associated aquatic ecosystems.