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.     

Comparative effect of selenium in wheat, barley, fish meal and sodium selenite for prevention of exudative diathesis in chicks

Groups af White Leghorn chicks obtained from dams deprived on selenium (Se), were fed from hatching a low-Se-vitamin E basal diet alone, or supplemented with 0.02, 0.04, 0.06 or 0.08 mg Se/kg diet, as sodium selenite (Na2SeO₃ · 5H₂O), wheat, barley or fish meal. Prevention of the Se-vitamin E deficiency responsive disease exudative diathesis (ED) as it was clinical observed, induction of the plasma Se dependent enzyme glutathione peroxidase (GSH-Px) activity, and Se concentration in the cardiac muscle were observed to be dietary Se level and source dependent. Slope ratio assay was applied to estimate the biological availability of Se in the natural sources relative to Se in sodium selenite. For the prevention of ED, the bioavailability of Se in wheat, barley and fish meal was 99, 85 and 80 %, respectively. The increase in the plasma GSH-Px activity revealed a bioavailability for Se in wheat, barley and fish meal of 79, 71 and 66 %, respectively. Using retention of Se in the cardiac muscle as the bioassay, a bioavailability of 108, 87 and 100 % was calculated for wheat, barley and fish meal Se, respectively.     

壳聚糖硒对蛋雏鸡生长、组织硒含量及血清肝酶活性的影响

为探索壳聚糖硒对蛋雏鸡生长、组织硒含量及血清肝酶活性的影响,选取135只1日龄SPF蛋雏鸡,随机分为3组:一组为对照组,饲喂基础日粮;二组和三组在基础日粮中分别添加硒水平为0.15 mg/kg的亚硒酸钠和壳聚糖硒。结果显示:14日龄时亚硒酸钠组和壳聚糖硒组的耗料量、血清碱性磷酸酶(AKP)活性和胸肌、心肌、肾脏、全血的硒含量显著高于对照组(P<0.05),壳聚糖硒组心肌和肝脏的硒含量显著高于亚硒酸钠组(P<0.05);28日龄时壳聚糖硒组与亚硒酸钠组的体重、血清AKP活性和肝脏、肾脏、胸肌、心肌、全血的硒含量显著高于对照组(P<0.05),壳聚糖硒组的耗料量和肾脏、心肌、全血的硒含量显著高于亚硒酸钠组(P<0.05)。研究表明:壳聚糖硒能促进鸡的生长和硒的沉积,提高血清AKP活性,且效果优于亚硒酸钠。     

Is Leucaena leaf useful as a selenium supplement for growing Philippine goats?

The effects of Leucaena leucocephala leaf (LL) supplementation on selenium (Se) status of growing Philippine goats were determined in the present study. A total of 12 3–4 month old male goats with mean bodyweight of 8.8 kg was used. All animals received a basal diet comprised of different forages. Six of the animals were supplemented with LL (22.9% CP) while the remaining six animals were not supplemented (control). The rate of LL to the total forage diet offered to the LL‐supplemented animals was 25%. Bodyweight measurement, blood and forage sampling were carried out every 2 weeks during the 4 months of experiment. Selenium, sulfur, calcium, phosphorus, magnesium, copper and zinc concentrations were analyzed after wet digestion. Leucaena leaf seemed to have higher Se and calcium, but lower copper and zinc concentrations than was observed in grasses fed to the animals. Bodyweight of growing goats in LL‐supplemented group tended to be higher than that of control animals. Supplementation of LL resulted in high whole blood Se concentration of growing goats. In the last month of this experiment, whole blood in all supplemented animals contained higher Se concentration than the deficient level of 20 ng/mL, while Se concentration in the control group was slightly above the deficient level.     

不同硒源及硒水平对大鼠生长性能、血清抗氧化能力和组织硒沉积的影响

本试验旨在考察不同硒源及硒水平对大鼠生长性能、血清抗氧化能力及组织硒沉积的影响,并以亚硒酸钠和商品酵母硒(酵母硒B)为参比,对本课题组用糖蜜和尿素为发酵底物研制的酵母硒(酵母硒A)生物学效价进行评定.将硒耗竭2周后的70只8周龄左右Wistar雌性大鼠称重,随机分到10个处理,每个处理7个重复,每个重复1只大鼠,分别饲喂不同处理的饲粮21d.处理1不添加任何形式的硒源,处理2～9在基础饲粮中分别以亚硒酸钠或酵母硒A的形式添加0.1、0.2、0.3和0.4mg/kg硒,处理10以酵母硒B形式添加0.3mg/kg硒.结果表明:1)不同硒源及硒水平对大鼠生长性能、血清谷胱甘肽过氧化物酶(GSH-Px)和超氧化物歧化酶活性影响不显著(P＞0.05);2)组织硒含量随饲粮硒水平的升高极显著增加(P＜0.01),添加酵母硒A组大鼠组织硒含量显著高于亚硒酸钠组(P＜0.05);3)以亚硒酸钠为参比,血清GSH-Px活性及肝脏、肾脏和肌肉硒含量作为判定指标,酵母硒A的相对生物学效价分别为95.9％、127.5％、114.5％和101.2％;4)添加酵母硒A和酵母硒B对大鼠生长性能、血清抗氧化能力的影响不显著(P＞0.05),但添加酵母硒A组大鼠肾脏硒含量极显著高于酵母硒B组(P＜0.01),而酵母硒B在肌肉中有更多的硒沉积(P＜0.01).结果提示:1)硒源对大鼠组织硒沉积有较大影响,酵母硒相对于亚硒酸钠具有更高的生物学效价,但不同酵母硒之间存在一定的差异;2)饲粮硒水平对大鼠血清抗氧化能力影响较小,以血清GSH-Px活性为衡量标准,0.1mg/kg硒的酵母硒和亚硒酸钠都能满足大鼠的需要,但更高水平的酵母硒可以使大鼠组织中有更多硒的储备.     

鱼油与硒对饲喂亚麻籽日粮绵羊体组织脂肪酸组成及抗氧化的影响

研究0.33%鱼油与2mg/kgDM的有机硒对饲喂亚麻籽日粮的绵羊体组织脂肪酸组成及抗氧化功能的影响。初步探讨在绵羊日粮中添加亚麻籽提高体组织CLA含量的同时,再添加鱼油和硒是否能进一步提高CLA含量。选用体重相近,健康的杂交一代公羔羊16只,随机分为4组。4组日粮为对照组LD组(基础日粮+10%亚麻籽),LF组(基础日粮+0.33%鱼油+9.17%亚麻籽,其中0.33%鱼油+9.17%亚麻籽所含脂肪与10%亚麻籽脂肪含量相等),LDSe组(基础日粮+10%亚麻籽+2mg Se/kgDM);LFSe组(基础日粮+0.33%鱼油+9.17%亚麻籽+2mgSe/kg DM),硒以有机硒的形式添加。结果表明:硒的添加对绵羊血浆抗氧化功能无显著影响(P<0.05),可能是受基础日粮硒浓度的影响;亚麻籽日粮中添加0.33%鱼油提高了绵羊体组织cis-9,trans-11-CLA和trans-11-C18:1含量。亚麻籽日粮中添加2mg Se/kg DM的有机硒对绵羊体组织脂肪酸组成没有显著影响。鱼油与有机硒的添加对绵羊不同组织△9-脱氢酶活性各组间影响差异不显著。由此表明,日粮中联合添加亚麻籽+鱼油以提高组织CLA含量的效果优于单独添加亚麻籽。     

蛋鸡日粮中添加富硒酵母对鸡蛋中硒含量及分布的影响

试验选用产蛋率约为80%的罗曼褐蛋鸡35只,随机分为7组,进行为期30d的饲养试验。A组为对照组,饲以基础日粮,其余6组为试验组,B、C、D组在基础蛋鸡日粮中分别添加0.2mg/kg、0.5mg/kg、1mg/kg硒的亚硒酸钠,E、F、G组在基础蛋鸡日粮中分别添加0.2mg/kg、0.5mg/kg、1mg/kg硒的富硒酵母。试验过程中记录蛋鸡的生产性能,每隔7d从各试验组鸡所产的鸡蛋中任取3枚,测定鸡蛋中硒的含量,并于试验的第14、15天,28、29天从A、C、F组每组各取5枚鸡蛋分别测定蛋黄和蛋清的硒含量。结果显示,日粮中添加硒对蛋鸡生产性能无显著影响,能极显著提高鸡蛋中硒含量,并且硒主要存在蛋黄中,添加富硒酵母组蛋硒含量较亚硒酸钠组提高更为显著。     

Bioavailability to chicks of selenium in barley, oats and meat meal

Day-old White Leghorn chicks deficient in selenium (Se) were fed a low Se basal diet (containing adequate level of vitamin E) for 2 weeks depletion period before they were given the experimental diets containing different levels of Se for 4 weeks. Dietary treatments contained 0.03, 0.06, 0.09 or 0.12 mg Se/kg as sodium selenite, barley, oats, meat meal or their extracted counterparts. Plasma GSH-Px activity was observed at weekly intervals, while the Se concentration of plasma and liver were determined at the end of the study. The biological availability of Se in the test ingredients was measured by the induction of plasma GSH-Px activity. In comparison to sodium selenite (100 %) it was: 77 % for barley, 80 % for extracted barley, 37 % for oats, 62 % for extracted oats, 20 % for meat meal, and 26 % for extracted meat meal. Using the retention of Se in plasma as a criterion, the following biological availability of Se was observed: barley 151 %; extracted barley 102 %; oats 90 %; extracted oats 107 %; meat meal 40 %; and extracted meat meal 47 %. Similarly, the efficiency of the test ingredients in increasing the Se concentration in liver was: barley 82 %; extracted barley 90 %; oats 67 %; extracted oats 98 %; meat meal 26 %; and extracted meat meal 31 %. The greater biopotency of the natural Se sources for increasing the Se concentration of the chick tissues than for inducing the plasma GSH-Px activity in comparison to sodium selenite, indicated that proportionally less amounts of the Se retained in the chick plasma from the natural sources were incorporated into the metabolic active form of Se, i.e., GSH-Px. Therefore, the plasma GSH-Px activity was suggested as the more reliable criterion to be used for the evaluation of the bioavailability of Se.     

Investigation into selenium requirement of growing turkeys offered a diet supplemented with two levels of vitamin E

To evaluate dietary selenium (Se) requirement in turkeys offered a diet supplemented with two levels of vitamin E (VE), 96 newly hatched male BIG 6^® chicks (58.4 ± 4.12 g) were divided into eight groups of 12 animals each and fed maize soya diets containing 0.05, 0.10, 0.20 and 0.30 mg Se/kg from sodium selenate in combination either with the natural VE content (approximately 10 IU/kg) or with a VE addition of 50 IU/kg. Animals from all the groups were highly performant and their final body weights (1746 ± 190 g) after 35 days on experiment were not significantly different. According to its dietary supply, Se concentration in the liver and plasma increased dose dependently. Independent of dietary VE, the activities of GPx3 in plasma and of GPx1 in liver and breast muscle increased to a larger extent in turkeys supplemented with 0.10 and 0.20 mg Se/kg in relation to animals with low marginal Se supply (0.05 mg/kg). Supplementation of 0.30 mg Se/kg only slightly increased further selenoprotein activities. 2‐Thiobarbituric acid reactive substances in the liver were strongly reduced by dietary VE, but not by Se. Plasma aspartate aminotransferase (AST) and creatine kinase (CK) activities did not show muscular lesions in none of the groups. Although there were no signs of muscular lesions even in turkeys with marginal Se and moderate VE supply, the activity of selenoproteins in various organs increased up to 0.30 mg Se/kg diet, independent of VE supply. It was concluded that for growing turkeys the Se supply should meet at least a level of 0.20 mg/kg diet as currently recommended by the National Research Council and Gesellschaft für Ernährungsphysiologie. Vitamin E addition confirmed the particular function of the vitamin as a lipid antioxidant and should be taken into consideration when diets with high PUFA concentrations are fed.     

Effects of dietary supplementation of selenium and iodine on growth performance,carcass characteristics and histology of thyroid gland in goats

This study assessed the effects of dietary selenium (Se), iodine (I) and a combination of both on growth performance, thyroid gland activity, carcass characteristics and the concentration of iodine and selenium in Longissimus lumborum (LL) muscle in goats. Twenty‐four bucks were randomly assigned to four dietary treatments: control (CON), basal diet without supplementation, basal diet + 0.6 mg Se/kg dry matter (DM) (SS), 0.6 mg I/kg DM (IP), or combination of 0.6 mg/kg DM Se and 0.6 mg/kg DM I (SSIP) and fed for 100 days. Animals fed diet SSIP exhibited higher (P < 0.05) body weight and better feed conversion ratio (FCR) than those fed other diets. Dressing percentage of goats fed the supplemented diets was higher (P < 0.05) than that of the control. Carcasses from the IP group had higher (P < 0.05) total fat proportion than the SSIP group. The levels of both elements were significantly elevated (P < 0.05) in LL muscle in supplemented goats. Thyroid follicular epithelial cells of IP and SSIP animals were significantly higher than those of CON and SS groups. The study demonstrated that the combined Se and I dietary supplementation improves growth performance, carcass dressing percentage and increases the retention of Se and I in goat meat.     

Estimation of the selenium requirement of growing guinea pigs (Cavia porcellus)

The aim of the study was to determine the selenium (Se) requirement of guinea pigs as a species unable to synthesize ascorbic acid. Forty-nine male guinea pigs (average weight 208 ± 3.5 g) were divided into an initial status group and six experimental groups. The animals received a Se deficient Torula yeast based basal diet (<0.02 mg Se and 26 mg α-tocopherol/kg) or a Se addition of 0.05, 0.10, 0.15, 0.20 and 0.25 mg/kg diet as sodium selenate for 10 weeks. There was no significant difference in weight gain (final weight 643 ± 21 g) between the groups and no clinical symptoms of Se deficiency occurred. With the exception of the testes, there was an increasing Se concentration in liver, plasma and haemolysate dependent on supplementation level. Glutathione peroxidase was determined in the plasma and Se dependent glutathione peroxidase (GPx1) in haemolysate, liver, kidney, heart and lung. Thioredoxin reductase (TR) activity was measured in liver, kidney and heart and deiodinase activity in the liver. A phospholipid hydroperoxide reducing activity with Se influence was determined in liver, kidney, heart, testes and brain. With the exception of GPx1 activity in heart and haemolysate and TR activity in the kidney, all enzymes already reached their maximal activity at 0.05 mg Se/kg diet. The activities of GPx1 and TR were used as parameters for broken line analysis and a Se requirement of 0.080 mg Se/kg diet was derived as sufficient for growing guinea pigs adequately supplied with vitamin E.     

硒源与硒水平对军曹鱼幼鱼生长性能、肝脏和血清抗氧化指标及组织硒含量的影响

本试验旨在研究硒源和硒水平对军曹鱼幼鱼生长性能、肝脏和血清抗氧化指标及组织硒含量的影响,以确定军曹鱼幼鱼对不同硒源的最适需要量。在基础饲料中分别添加0(对照)、0.3、0.6、0.9和1.2 mg/kg(以硒计)的亚硒酸钠(Se-S)或蛋氨酸硒(Se-Met),配制9种试验饲料(共用对照饲料),饱食投喂初始体重为(22.18±0.35)g的军曹鱼幼鱼10周。每种试验饲料投喂3个网箱(重复),每个网箱放养30尾试验鱼。结果表明:1)硒水平对特定生长率(SGR)和增重率(WGR)有极显著影响(P0.01),但对成活率(SR)和饲料系数(FCR)无显著影响(P0.05);硒源及硒源与硒水平的交互作用对SGR、W GR、FCR和SR均无显著影响(P0.05)。SGR和W GR随着硒水平的升高先升高后降低。2)硒水平极显著影响肝脏谷胱甘肽过氧化物酶(GSH-Px)、谷胱甘肽还原酶(GR)活性和丙二醛(MDA)含量及血清GSH-Px活性(P0.01),并显著影响血清GR活性(P0.05);硒源极显著影响肝脏GR、总超氧化物歧化酶(T-SOD)、过氧化氢酶(CAT)活性和MDA含量及血清T-SOD活性(P0.01);硒源和硒水平的交互作用显著影响肝脏CAT活性和MDA含量及血清T-SOD活性(P0.05)。肝脏和血清GSH-Px活性随着硒水平的升高呈先升高后稳定趋势,GR活性呈先下降后稳定趋势。2种硒源均在添加量为0.9 mg/kg时有最高的肝脏GSH-Px活性,最低的肝脏GR活性。肝脏CAT活性随着硒水平的升高逐渐升高。3)脊椎骨、全鱼和肝脏硒含量随硒水平的升高而增加。硒源极显著影响脊椎骨硒含量(P0.01),硒源和硒水平的交互作用极显著影响肝脏和脊椎骨硒含量(P0.01)。以蛋氨酸硒和亚硒酸钠为硒源,通过二次回归曲线分析得出饲料硒水平分别为1.29和1.46 mg/kg时军曹鱼幼鱼可以获得最大SGR。以SGR和全鱼硒含量为判据,军曹鱼幼鱼对蛋氨酸硒的生物利用率分别相当于亚硒酸钠的1.20和2.90倍。     

Selenium and vitamin E deficiency in pigs. II. Influence on plasma selenium, vitamin E, ASAT and ALAT and on tissue selenium.

The effect of dietary selenium (Se) and vitamin E (Vit. E) in pigs on Se and Vit. E in plasma and on Se in tissue from liver, heart, m. long, dorsi and m. psoas major was studied; and furthermore was the influence on the enzymes ASAT and ALAT studied.Two levels of Se were used, 0.03 and 0.06 mg Se per kg feed. Within each Se level 2 levels of Vit. E were used, 15 and 45 i. u. per kg feed. This resulted in 4 groups: 1. low Se and low Vit. E; 2. low Se and high Vit. E; 3. high Se and low Vit. E; 4. high Se and high Vit. E.Ten% of all pigs fed low Se, and 4% of the pigs fed low Se and high Vit. E diet died with severe symptoms of Se deficiency. None of the pigs fed the high Se diet died with such symptoms. Plasma Se determinations have been shown to indicate the Se status in pigs almost as accurately as liver Se determination. ASAT and ALAT enzyme determinations were not of any diagnostic value.There was a good agreement between dietary Vit. E level and the corresponding levels in plasma. Oxidized herring oil seems to enhance the Vit. E need.     

Effect of Se and VE Supplement on Semen Quality,Antioxidant Enzyme Activities and Heat Shock Protein Expression of Goat in High Temperature Season

This experiment was conducted to study the effect of selenium and vitamin E supplement on semen quality, antioxidant enzyme activities and heat shock protein expression of goat in Hainan high temperature season.16 adult Hainan Black goat with good health and approximate weight were randomly divided into 4 groups, fed with basal diet(control group), basal diet+0.5 mg/kg Se(Se group), basal diet+100 mg/kg VE(VE group), and basal diet+0.5 mg/kg Se+100 mg/kg VE(Se+VE group), respectively.The experimental period was 93 d.Semen samples were collected in the last week of the experiment on two consecutive days.The semen quality, antioxidant enzyme activities and heat shock protein expression were analyzed.The results showed that compared with control group, the ejaculate volume was not significantly affected by Se or VE supplement(P>0.05).Sperm density and sperm motility were increased significantly by Se and VE supplement(P<0.05), and the abnormal rate was decreased extremely significantly(P<0.01).The goats fed with Se and VE also had higher activities of GSH-Px(P<0.01), SOD(P<0.05), CAT(P<0.05) and T-AOC(P<0.01), and lower MDA concentration in seminal plasma(P<0.05).The relative expression levels of HSP70 and HSP90 mRNA in supplement groups were decreased extremely significantly(P<0.01).However, there were some certain differences between the Se and VE supplement groups on semen quality and heat shock protein expression.In conclusion, the supplementation of Se and VE could help to improve goat semen quality by increasing the sperm density, sperm motility, the antioxidant enzyme activities, and decreasing the abnormal rate in hot season of Hainan.Finally, Se and VE supplement had good effects on relieving the environment heat stress.     

Depot injection of barium selenate for long-term prevention of selenium inadequacy in beef cattle

In southern Australia, cattle at risk from selenium (Se) deficiency can be given an oral dose of supplements that are effective in maintaining adequate Se status for between 9 and 12 months. The present study was undertaken to assess the duration of the effect of parenteral barium selenate (BaSe) in raising the Se status of cattle at pasture in an area of marginal Se deficiency. The BaSe was given subcutaneously to Hereford heifers, using an 18-gauge needle. Cattle had regular blood sampling to assay Se, from 8 days before dosing to 1155 days afterwards. Results show that a single injection of BaSe was effective in elevating blood and plasma Se concentrations to normal values for at least 2 to 3 years, when given to beef cattle of low normal Se status. We suggest that a prophylactic dosage of 0.5 mg Se/kg body weight as BaSe should be given every 2 years to prevent Se inadequacy in beef cattle grazing pasture of marginal Se content.     

酵母硒对绿壳蛋鸡生产性能、蛋品质、抗氧化能力及蛋黄硒含量的影响

试验选用270只44周龄健康江西东乡黑羽绿壳蛋鸡,随机分成3组,每组5个重复,每个重复18只鸡,采用单因子完全随机试验设计,1组为对照组,2、3组在饲喂相同基础日粮基础上分别以酵母硒形式添加Se 0、0.25、0.50 mg/kg,预试期7 d,正试期28 d。结果表明,在基础日粮中添加0.25、0.50 mg/kg对平均蛋重、产蛋率、合格蛋率、料蛋比和死淘率均无显著影响(P>0.05),可极显著减缓蛋在贮存过程中蛋白质品质的下降(P<0.01),极显著升高蛋黄中硒的含量(P<0.01);显著或极显著提高蛋鸡血清总超氧化物歧化酶、谷胱甘肽过氧化物酶活性(P<0.05或P<0.01)和总抗氧化能力(P<0.01),极显著降低血清丙二醛含量(P<0.01)。综合考虑,基础日粮中酵母硒的适宜添加量为0.25 mg/kg。     

补饲硒和维生素E对高温季节山羊精液品质、抗氧化酶活性及热休克蛋白表达的影响

试验旨在研究在海南夏季高温饲养条件下,山羊补饲硒和维生素E对其精液品质、抗氧化酶活性及热休克蛋白表达的影响。选用16只健康状况良好、体重相近的海南黑山羊成年公羊,随机分成4组,分别饲喂基础日粮(对照组)、基础日粮+0.5mg/kg Se(Se组)、基础日粮+100mg/kg VE(VE组)和基础日粮+0.5mg/kg Se+100mg/kg VE(Se+VE组),试验期93 d。试验期结束前1周采集精液,评价精液品质、测定精浆抗氧化酶活性和精液热休克蛋白表达。结果表明,与对照组相比,补饲Se和VE对海南黑山羊射精量影响差异不显著(P>0.05);补饲Se和VE能显著提高海南黑山羊的精子密度和精子活力(P<0.05),极显著降低精子畸形率(P<0.01);极显著增加精浆谷胱甘肽过氧化物酶活性和总抗氧化能力(P<0.01),显著增加超氧化物歧化酶和过氧化氢酶活性(P<0.05),显著降低丙二醛浓度(P<0.05);补饲Se和VE还极显著降低了精液HSP70和HSP90mRNA的表达水平(P<0.01),但各补饲组之间对精液品质改善效果和热休克蛋白表达丰度的影响存在一定差异。综上所述,补饲Se和VE有助于提高热带地区夏季高温季节山羊精子密度、精子活力,降低畸形率,同时还能增强精浆中抗氧化酶的活性,改善精液品质,进而起到缓解环境热应激的效果。     

Effect of vitamin E supplementation of sheep and goats fed diets supplemented with polyunsaturated fatty acids and low in Se

Vitamin E (VitE) and selenium (Se) are an essential part of the antioxidative functions of metabolism. There are situations of low supply of both micronutrients. As VitE is involved in ruminal biohydrogenation of polyunsaturated fatty acids (PUFA) and their protection against oxidation in metabolism, diets supplemented with PUFA may challenge VitE to an extent making recommended supplies insufficient. Twelve goats and sheep each were fed a diet supplemented with PUFA and characterised by low Se and limited VitE contents during the last 2 months of gestation and the first 2 months of lactation. The basal diet consisted of hay and concentrate. Six goats and sheep received extra VitE, while the control groups received no extra VitE. Blood and milk samples were taken. In addition, liver, heart muscle and spleen samples were obtained from the offspring after slaughtering at an age of 8 weeks. No significant changes were observed in serum Se and VitE. A significant increase in serum VitE concentrations between 2 and 4 weeks postpartum (pp) was evident in the supplemented kids. In 4, 6 and 8 weeks pp, the serum concentrations of VitE in the supplemented kids were significantly higher compared to the unsupplemented group. In the kids, VitE was higher in liver of the supplemented groups. There were no significant differences in response to extra VitE between sheep and goat. The kids responded to serum VitE different from that of lambs, as a significant difference was observed between supplemented and unsupplemented animals in the goat kids, but not the lambs. In conclusion, goats and sheep have to be viewed differently and may not be considered alike relating to VitE/Se metabolism and requirements, especially in young animals.     

Bioavailability of co‐supplemented organic and inorganic zinc and selenium sources in a white fishmeal‐based rainbow trout (Oncorhynchus mykiss) diet

The bioavailability of trace elements in fishmeal diets is influenced by their chemical forms and dietary anti‐nutritional factors. In formulated fish feed, supplemented organically bound minerals may be more bioavailable than inorganic minerals. A 10‐week feeding trial was undertaken with rainbow trout (Oncorhynchus mykiss) to determine whether the inclusion of organically bound selenium (Se) and zinc (Zn) improved uptake and assimilation of these elements compared to commonly used inorganic forms. The three diets tested included a control diet, no added Zn or Se; an organic Se‐yeast and Zn‐proteinate supplemented diet; and an inorganic sodium selenite and Zn‐sulphate supplemented diet. The endpoints tested were apparent digestibility, whole body levels, tissue distribution and Se‐ and Zn‐dependent enzyme activities. Digestibility of residual Se in the basal diet was 54.2 ± 1.0% and supplemented Se‐yeast was significantly more digestible than selenite (p < 0.05). Digestibility of residual Zn was 21.9 ± 2.0% and no significant difference was found between the treatments (p = 0.89). Whole body Se was raised by both Se sources and to a greatest extent by Se‐yeast (p < 0.001). Zn‐sulphate, and to a lesser extent Zn‐proteinate, both raised whole body Zn (p < 0.05). Dietary Zn in the basal diet was found to be above requirements, yet Zn‐sulphate had a significantly greater retention than Zn‐proteinate in those tissues that responded to Zn supplementation. Se‐yeast significantly raised Se in all tissues to a greater extent than selenite, except in the pyloric caeca and liver where the greatest increases were by selenite. Only Se‐yeast elevated Se‐dependent thioredoxin reductase activity (p < 0.05) and neither forms of Se affected glutathione peroxidise activity (p = 0.059). Alkaline phosphatase and carboxypeptidase B were not affected by Zn supplementation (p = 0.51 and p = 0.88 respectively). In all aspects, Se‐yeast was found to be a highly bioavailable form of Se in comparison to selenite. Because of its superior bioavailability, organically bound Se would be a preferred Se source for supplementation of fishmeal trout diets than selenite.     

不同硒源及水平对肉鸡组织硒含量及抗氧化功能的影响

本文旨在研究和比较不同硒源及水平对爱拔益加(AA)肉鸡生长性能、组织硒含量和抗氧化功能的影响,并探讨在生产中应用较低水平(0.20 mg/kg)有机硒替代较高水平(0.30 mg/kg)无机硒的可行性.选用1日龄AA肉仔鸡600只,随机分为5组,分别饲喂基础饲粮(对照组)及在基础饲粮中添加0.30 mg/kg硒(以亚硒酸钠形式)(SS组)、0.20 mg/kg硒(以酵母硒形式)(SY Ⅰ组)、0.30 mg/kg硒(以酵母硒形式)(SYⅡ组)和0.30 mg/kg混合硒(亚硒酸钠和酵母硒形式硒各0.15mg/kg)(MS组)的试验饲粮,每组6个重复,每个重复20只鸡.试验期42 d.结果表明:1)SYⅡ组肉鸡前期平均日采食量显著低于对照组(P＜0.05),饲粮添加各水平有机硒均显著降低了肉鸡全期平均日采食量(P ＜0.05或P＜0.01).2)与对照组和SS组相比,添加各水平有机硒均显著提高了肉鸡胸肌中的硒含量(P＜0.01),且以SYⅡ组最高,显著高于其他各组(P＜0.01);SY Ⅰ组和SYⅡ组肉鸡血浆中的硒含量显著高于对照组(P ＜0.05或P＜0.01);添加各水平有机硒均显著提高了42 d肉鸡肝脏中的硒含量(P ＜0.05或P＜0.01).3)在试验前期(1 ～21 d),较SS组,SYⅡ组肉鸡血浆谷胱甘肽过氧化物酶(GSH-Px)和总超氧化物歧化酶(T-SOD)的活性均显著提高(P＜0.05);较对照组,SS组、SY Ⅰ组和SYⅡ组肉鸡肝脏T-SOD的活性均显著提高(P＜0.05或P＜0.01).在试验后期(22 ～42 d),较对照组,SS组、SY Ⅰ组和SYⅡ组肉鸡血浆和肝脏GSH-Px的活性均显著提高(P＜0.05或P＜0.01),各添加有机硒组肉鸡的血浆丙二醛含量均显著降低(P＜0.05或P＜0.01);与对照组相比,MS组肉鸡肝脏过氧化氢酶(P＜0.05)和GSH-Px的活性均显著提高(P＜0.01).由此可知,饲粮添加0.30 mg/kg酵母硒能够提高肉鸡组织硒沉积量,对其生长性能和抗氧化功能的改善效果最佳;饲粮添加0.20 mg/kg的酵母硒替代0.30 mg/kg亚硒酸钠,在改善肉鸡的生长性能、提高组织硒含量和抗氧化功能方面是可行的.