The effect of dietary vitamin E level on selenium status in rats

The effect of varying levels of dietary vitamin E on selenium status was determined using 40 Wistar rats with similar initial body weight. The rats were equally divided into four groups and fed the following dietary treatments (mg vitamin E/kg DM): 18 (control; C‐diet), 0 (0E‐diet), 9 (0.5E‐diet) and 36 (2E‐diet) for either 4‐week (Phase 1) or 8‐week (Phase 2) period. At the end of experiment, animals were slaughtered to measure vitamin E and selenium levels in the brain, liver, spleen, kidney, muscles and blood tissues. Dietary vitamin E levels did not affect feed and water intake and body weight. But whole‐blood selenium concentration in rats fed 0E‐diet was higher than in rats fed 2E‐diet after 4 weeks. Selenium level in muscle, spleen and brain was also higher (p < 0.05) in rats fed the 0E‐diet than in rats fed C‐diet after 4 weeks of feeding. On the other hand, selenium level in the muscle was lower (p < 0.05) in rats fed 0.5E‐diet than in those fed 0E‐diet after 4 weeks of feeding, but not after 8 weeks of feeding. Increasing dietary vitamin E level directly influenced selenium content of the spleen and brain after 8 weeks of feeding 2E‐diet. Moreover, the twofold increase in vitamin E intake resulted in a tendency to reduce whole‐blood selenium level and total selenium in the liver and kidney after 4 and 8 weeks. The results showed that the increasing dietary vitamin E level resulted in a tendency to reduce Se contents in some vital organs of the body such as the liver and kidney, suggesting their close compensatory interrelationship. Therefore, dietary vitamin E level directly influenced selenium metabolism in the animal body.     

The effect of oral metformin on insulin sensitivity in insulin-resistant ponies

Metformin may be an effective therapeutic option for insulin-resistant (I-R) horses/ponies because, in humans, it reportedly enhances insulin sensitivity (SI) of peripheral tissues without stimulating insulin secretion. To determine the effect of metformin on insulin and glucose dynamics in I-R ponies, six ponies were studied in a cross-over design by Minimal Model analysis of a frequently-sampled intravenous glucose tolerance test (FSIGT). Metformin was administered at 15 mg/kg bodyweight (BW), orally, twice-daily, for 21 days to the metformin-treated group. The control group received a placebo. A FSIGT was conducted before and after treatment. The Minimal Model of glucose and insulin dynamics rendered indices describing SI, glucose effectiveness (Sg), acute insulin response to glucose (AIRg) and the disposition index (DI). The body condition score (BCS), BW and cresty neck score (CNS) were also assessed. There was no significant change in SI, Sg, AIRg, DI, BW, BCS or CNS in response to metformin, or over time in the control group. There were no measurable benefits of metformin on SI, consistent with recent work showing that the bioavailability of metformin in horses is poor, and chronic dosing may not achieve therapeutic blood concentrations. Alternatively, metformin may only be effective in obese ponies losing weight or with hyperglycaemia.     

The effect of guaiphenesin on romifidine/ketamine anaesthesia in ponies

The purpose of this study was to investigate the effect of a single dose (50 mg/kg) of guaiphenesin on recumbency time, surgical conditions and the ‘quality’ of anaesthesia in ponies anaesthetised for castration. Sixteen ponies were sedated with romifidine 100 μg/kg and anaesthetised with ketamine (2.2 mg/kg). Ponies allocated to Group A received no treatment and those in Group B were given 50 mg/kg of a 15% guaiphenesin solution. Guaiphenesin was given as a rapid iv injection immediately after induction of anaesthesia. All ponies were subsequently castrated. The mean (± se) time of recumbency in Group A was 20.9 ± 1.37 min and in Group B 27.2 ± 2.1 min to (P<0.05). Subjective assessment scores for the quality of surgical conditions and anaesthesia itself were significantly greater (indicating better conditions) in ponies receiving guaiphenesin, although there was no difference between groups in the quality of recovery.     

獭兔日粮中硒需要量的研究

为了研究獭兔目粮中硒的需要量,试验以72只50日龄吉戎-Ⅱ生长獭兔为研究对象,随机分成6组,在玉米-豆粕型日粮的基础上分别添加0,0.10,0.25,0.40,0.55,0.70 mg/kg水平的硒.结果表明:日粮硒水平对獭兔日增重、皮张面积及血清总蛋白、白蛋白、T3、T4影响显著(P<0.05);獭兔日粮中硒的适宜添加量为0.25 mg/kg.     

Halothane-sparing effect of benzodiazepines in ponies

The halothane-sparing effect of 2 benzodiazepines, diazepam and temazepam, were investigated in ponies by measuring the minimum alveolar concentration (MAC) for halothane before and after drug administration. The MAC value for halothane decreased 29% and 16% when either 0.044 mg/kg of diazepam or 0.044 mg/kg of temazepam, respectively, was administered intravenously. Heart rate, respiratory rate, systolic and mean arterial blood pressure, and expired CO2 were also measured. No differences were present in these variables before and after drug administration nor were differences noted between the benzodiazepines.     

The influence of dietary selenium levels on blood levels of selenium and glutathione peroxidase activity in the horse

Twenty mature geldings, averaging 535 kg, were used to determine the influence of dietary selenium (Se) on the blood levels of Se and Se-dependent glutathione peroxidase (SeGSH-Px) activity in the horse. Horses were randomly assigned within breed to four treatments consisting of five horses each and fed a basal diet containing .06 ppm of naturally occurring Se. Diets were supplemented with .05, .10 and .20 ppm Se, as sodium selenite. Blood was drawn for 2 wk before, and for 12 wk following, the inclusion of supplement Se in the diets. Whole blood and plasma Se concentrations and plasma SeGSH-Px activities were determined from all blood samples. Selenium concentrations in plasma and whole blood increased linearly from wk 1 to wk 5 and 6, respectively, in Se-supplemented horses. After these times, no significant changes in Se concentration were observed in Se-supplemented or in unsupplemented horses throughout the remainder of the 12-wk trial. Plasma Se reached plateaus of .10 to .11, .12 to .14, and .13 to .14 micrograms/ml in horses supplemented with .05, .10 and .20 ppm Se, respectively. Whole blood Se reached plateaus of .16 to .18, .19 to .21, and .17 to .18 micrograms/ml in horses supplemented with .05, .10 and .20 ppm Se, respectively. Plasma SeGSH-Px activity was not significantly affected by dietary treatment. Therefore, this enzyme was not a good indicator of dietary Se in these mature horses.     

Effect of reovirus infection and dietary levels of selected vitamins on immunocompetence of chickens

The immunocompetence of 8-week-old reovirus WVU 2937-infected and uninfected chickens fed various dietary levels of biotin, niacin, choline, or folic acid was evaluated in four experiments. Antibody production to sheep red blood cells (SRBC), wattle responses to phytohemagglutinin-P (PHA-P), and wattle responses of tuberculin-sensitized chickens to bovine-purified protein derivative (PPD) were examined in five chickens per treatment. Dietary deficiencies had no effect on the in vivo T-cell immune responses to PPD, PHA-P, or humoral hemagglutinating-antibody production to SRBC. Reovirus-infected and uninfected chickens fed biotin at double the National Research Council (1977) requirement demonstrated decreased PPD responses. Lower hemagglutinating-antibody titers in the uninfected chickens and increased titers in the infected chickens were observed in those fed 200% of the requirement of biotin when compared with the chickens fed 20% and 100% biotin diets. Reovirus infection had no effect on PPD and PHA-P responses. However, in the choline experiment, reovirus-infected chickens had elevated titers. These data indicate that reovirus infection had no adverse effect on the immunocompetence of chickens 8 weeks postinfection. Dietary deficiencies also had no adverse effect on the immunocompetence of 8-week-old reovirus-infected and uninfected chickens.     

The influence of high dietary intakes of energy and protein on third metacarpal characteristics of weanling ponies

The influence of high dietary intakes of protein and energy on bone development was described and the accuracy of radiographic photometry as an estimator of bone mineral content was determined. There were higher (P<.10) values for breaking strength and cortical area, and lower (P<.10) percentages of calcium and total mineral content in the bones of ponies on high planes of nutrition. These ponies developed at a faster rate than the normally fed ponies, suggesting that during accelerated growth bone mineral deposition may be reduced. Thus, high intakes of energy and protein appeared to increase the rate of skeletal growth while decreasing deposition of mineral into bone. These conditions may be related to bone failure from high compressive loads.Radiographic photometry was found to be an adequate predictor of bone mineral, calcium and phosphorus content in live ponies. However, care must be used in obtaining the radiographs to ensure the accurate estimation of mineral status.     

富硒日粮对鸡蛋品质及硒沉积的影响

试验选用45周龄龙华草鸡型蛋鸡288只,随机分为2组:对照组和富硒组;每组为144只。试验组在对照组的基础上添加富硒蛋白粉1.00 mg/kg(以硒计),试验期30 d。结果表明:高硒日粮对试鸡的产蛋量、产蛋率、蛋重等产蛋性能均无显著影响(P>0.05),对蛋重、蛋形指数、蛋壳厚度、蛋壳强度、蛋白高度、蛋黄颜色和蛋品新鲜度等蛋品质指标也无显著影响(P>0.05);但可使蛋中硒含量极显著提高(P<0.01)。     

The effect of submaximal exercise on the peripheral blood pressure of untrained ponies

A significant increase in systolic and diastolic peripheral blood pressure was recorded after 8 minutes submaximal exercise in untrained ponies. Blood pressure was recorded by a modified auscultatory method from the coccygeal artery.     

Influence of supplemental selenium on humoral immune responses in weaned beef calves

Influence of supplemental Se on humoral immune response was measured in 60 weaned beef calves with marginal blood Se status. Calves were fed a Se-deficient diet consisting of corn silage, corn grain, and soybean meal. Blood Se concentrations, primary and secondary humoral immune responses to hen egg lysozyme inoculation, and weight gain were determined in a 70-day trial. Calves fed 20 mg of Se/kg of mineral mixture ad libitum had lower antibody responses (P less than 0.02), compared with calves fed 20 mg of Se/kg of mineral mixture and given 0.1 mg of Se and 0.22 IU of vitamin E/kg of body weight, IM, or with calves fed 80, 120, 160, or 200 mg of Se/kg of mineral mixture. Calves fed 80, 120, 160, or 200 mg of Se/kg of mineral mixture had higher (P less than 0.001) blood Se concentrations on day 70, compared with calves fed 20 mg of Se/kg of mineral mixture and given 0.1 mg of Se and 0.22 IU of vitamin E/kg of body weight, IM. Selenium supplementation had no effect on weight gain.     

The influence of dietary selenium as selenium yeast or sodium selenite on the concentration of selenium in the milk of Suckler cows and on the selenium status of their calves

The aim of this trial was to determine whether the selenium status of suckling calves could be improved by supplementing their dams' diet with organic Se instead of sodium selenite. A herd of 103 Hereford cows, which were on grass paddocks all year round, was divided into two groups. Both groups had free access to a mineral supplement that contained 30 mg of Se/kg; for one group the source of the Se was a Se yeast product, and for the other group the source was sodium selenite. The basal feed contained .02 mg of Se/kg DM. During the trial, the mean daily consumption of the mineral supplement was approximately 110 g/cow. The calving season started in the middle of March and ended in the middle of May. Blood samples were taken from 11 cows and their calves in the yeast group and from nine in the selenite group at the end of April and again at the beginning of June, and milk samples were taken at the same times. At both samplings, the concentration of Se in whole blood and the activity of glutathione peroxidase (GSH-Px) in the erythrocytes of the cows and calves in the yeast group were higher than in the samples from the animals in the selenite group. The same pattern was seen for plasma, except for the cows at the first sampling. The mean concentrations of Se in whole blood from calves in the yeast and selenite groups were 130 and 84 microg/L, respectively, and plasma concentrations were 48 and 34 microg/ L, respectively. Mean Se concentration in the milk from the yeast group (17.3 microg/L) was higher than that in milk from the selenite group (12.7 microg/L). There were significant correlations (r = .59 to .68) between the concentrations of Se in the cow's milk or cow's whole blood compared with Se concentrations in the calves whole blood and plasma or with the erythrocyte GSH-Px activity of the calves. The Se status of the calves in the selenite group was considered to be marginal, but the status of the calves in the yeast group was considered to be adequate. Supplementation of the suckler cows' diet with organic Se in the form of Se yeast rather than sodium selenite improved the Se status of their calves when the Se was mixed into a mineral supplement containing 30 mg of Se/kg. In practice, such supplementation would probably eliminate the risk of nutritional muscular degeneration in suckling calves.     

微量元素硒对动物繁殖性能的影响

作者从微量元素硒的主要生物学功能，硒对各种动物繁殖性能的影响，常用饲料原料的含硒量，以及各种种用动物对硒的需要量方面进行比较全面的综述，为在种用动物饲养过程中合理利用微量元素硒提供科学依据。     

日粮中不同硒水平对大鳞副泥鳅肌肉品质的影响

将大鳞副泥鳅幼鱼随机分为5组,分别用含硒量为0.0(0.31)、0.1(0.39)、0.2(0.48)、0.4(0.50)和0.6(0.62)mg/kg的饲料投喂60 d,每组3个重复。试验结束后测定各组大鳞副泥鳅肌肉中的一般营养成分、矿物元素含量、氨基酸含量,并对其进行营养品质评价。结果表明:投喂不同硒含量的饲料对大鳞副泥鳅肌肉的水分、粗脂肪、粗蛋白没有显著影响(P>0.05),但在0.2(0.48)mg/kg饲料组其粗蛋白含量达到最大值,水分达最小值;灰分在0.1(0.39)、0.2(0.48)和0.4(0.50)mg/kg组显著或极显著低于对照组(P<0.05或P<0.01);Fe、Zn、Mn、Se、K、Na元素在0.2(0.48)mg/kg饲料组均显著或极显著高于对照组(P<0.05或P<0.01);TAA、EAA、EAAI和DAA与对照组相比均无显著性差异,但在0.1(0.39)mg/kg饲料组均达到最大值。     

Effect of dietary fatty acids on humoral immune response of Turkeys

1. This study examined the effect of increasing amounts of dietary polyunsaturated fatty acids on the fatty acid composition in serum and antibody production following a standard vaccination programme in growing turkeys. Turkey poults were fed on 5 diets containing 75g/kg added fat made up of different proportions of palm and soyabean oils, and were vaccinated against Newcastle disease, infectious bronchitis and necrotic enteritis according to a standard vaccination programme. Blood samples were taken before and one week after each vaccination.

2. Fatty acid composition in serum reflected the composition of the diets although arachidonic acid concentration was not changed by dietary fatty acid content. Growth, erythrocyte and leukocyte parameters were not affected by the respective diets.

3. Specific antibody production was related quadratically to serum linoleic and total n‐6 polyunsaturated fatty acid concentrations. No correlation was found with linolenic or arachidonic acids.

4. It is concluded that dietary fatty acid composition can augment the specific anti‐vaccine immune response in turkey poults.