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1.
The present study was conducted to assess the relative bioavailability of selenium (Se) as Se yeast (SY) relative to sodium selenite (SS) for broilers fed a conventional corn–soybean meal diet. A total of 360 one-d-old Arbor Acres commercial broilers were randomly assigned to 5 treatments with 6 replicates per treatment in a completely randomized design involving a 2 (Se sources: SY and SS) × 2 (added Se levels: 0.20 and 0.40 mg Se/kg) factorial design of treatments plus 1 (a Se-unsupplemented control diet) for 42 days. The results showed that Se concentrations in plasma, liver, heart, breast muscle, pancreas and kidney of broilers on d 21 and 42, glutathione peroxidase (GSH-Px) activity in the pancreas on d 21 as well as in the breast muscle and pancreas on d 42, and GSH-Px mRNA levels in the liver, heart, breast muscle and pancreas on d 21 increased linearly (p < .03) as levels of added Se increased. Furthermore, a difference (p ≤ .05) between SY and SS was detected for Se concentrations in plasma, liver, heart, breast muscle, pancreas and kidney, GSH-Px activity in pancreas on both d 21 and 42, as well as pancreatic GSH-Px mRNA level on d 21. Based on slope ratios from the multiple linear regressions of the above indices, the Se bioavailabilities of SY relative to SS (100%) were 111%–394% (p ≤ .05) when calculated from the Se concentrations in plasma, liver, heart, breast muscle, pancreas, kidney and GSH-Px activities in pancreas on d 21 and 42, as well as GSH-Px mRNA level in pancreas on d 21. The results from this study indicated that the Se from SY was more available for enhancing the Se concentrations in plasma or tissues and the expression and activity of GSH-Px in pancreas of broilers than the Se from SS.  相似文献   

2.
Biochemical and physiological indicators of selenium status in animals   总被引：1，自引：0，他引：1  
Selenium (Se) concentrations in animal tissues vary with the tissue and with the amount and chemical form of Se in the diet. In cattle, sheep and swine, Se concentrations rank in kidney greater than liver greater than heart greater than skeletal muscle greater than adipose tissue. Selenium concentrations (wet basis) in skeletal muscle of swine (.03 to .52 ppm) reflect natural dietary Se concentrations ranging from .03 to .49 ppm. Inorganic Se additions to diets low in natural Se (.05 ppm) increase skeletal muscle Se concentrations until dietary Se levels are adequate. After a period of Se repletion, skeletal muscle Se concentrations should be at least .08 ppm on a wet basis. Selenium concentrations in plasma, serum or whole blood are also related to inorganic Se intake and rise in direct relation to each other in the deficient to adequate range. Plasma or serum Se concentrations of .08 to .12 ppm are consistent with dietary adequacy. Selenium-dependent glutathione peroxidase (GSH-Px) activity of plasma or whole blood may also be used to assess Se status in some animals since plasma or whole blood Se concentrations are positively correlated with GSH-Px activity in animals that are low to adequate in dietary inorganic Se. However, inter-laboratory variation in GSH-Px values is large, and it is doubtful that limits of normalcy developed in one laboratory are applicable in others. In certain tissues it is important to distinguish between GSH-Px and glutathione (GSH) S-transferases, which can reduce organic hydroperoxides but which are not Se-dependent. It is also important that the instability of GSH-Px be considered so that losses in activity during handling and storage may be minimized. Urinary Se excretion and Se retention as percentages of Se intake may be helpful in assessing Se status when facilities for metabolism studies are available.  相似文献   

3.
不同硒源及水平对肉鸡组织硒含量及抗氧化功能的影响   总被引：1，自引：0，他引：1  
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.  相似文献   

4.
This study was conducted to determine the effects of either dietary Se source or dose on the Se status of horses. Twenty-five mature horses were blocked by BW and randomly allocated to 1 of 5 dietary treatments that comprised the same basal diet that differed only in Se source or dose. Treatments were as follows: negative control (0.085 mg of Se/kg of DM), 3 different dietary concentrations of supplemental organic Se (Se yeast; 0.2, 0.3, and 0.4 mg of total Se/kg of DM), and positive control (0.3 mg of total Se/kg of DM) supplemented with Na selenite. Horses initially received the control diet (6 kg of grass hay and 3 kg of concentrate per horse daily) for 56 d to allow diet adaptation. After the period of diet adaptation, horses were offered their respective treatments for a continuous period of 112 d. Jugular venous blood samples were collected before the morning feed on d 0, 28, 56, 84, and 112. Whole blood and plasma were analyzed for total Se, glutathione peroxidase activity in whole blood (GPX-1) and plasma, and thyroid hormones (thyroxine and triiodothyronine) in plasma. The proportion of total Se as selenomethionine (SeMet) or selenocysteine in pooled whole blood and plasma samples was determined on d 0, 56, and 112. Data were analyzed as repeated measures. Total Se in blood and plasma and GPX-1 activity were greater in all supplemented horses (P < 0.001, except P < 0.01 for GPX-1 in horses supplemented with the least dose of Se yeast) with a linear dose effect of Se yeast for whole blood and plasma Se (P < 0.001) and a quadratic dose effect (P < 0.05) for whole blood GPX-1 activity. A plateau for total Se in plasma was achieved within 75 to 90 d, although this was not observed in blood total Se or GPX-1 activity. On d 84 and 112, horses supplemented with Se yeast showed greater total Se in blood (P < 0.05) compared with horses supplemented with Na selenite, and a source effect (P < 0.05) was observed in the relationship between total blood Se and GPX-1 activity. Selenocysteine (the predominant form of Se in whole blood and plasma) increased in all horses supplemented with Se. The SeMet content of whole blood and plasma increased in horses supplemented with Se yeast, but it was not observed in those supplemented with selenite. The rate of increase in SeMet over time was greater in whole blood (P < 0.05) and plasma (P = 0.10) with the Se yeast product. In conclusion, Se yeast was more effective than Na selenite in increasing total Se in blood, mainly as consequence of a greater increase of the proportion of Se comprised as SeMet, but it did not modify GPX-1 activity.  相似文献   

5.
The objective of the study was to determine if there were adverse effects on animal health and performance when a range of ruminant animal species were fed at least 10 times the maximum permitted European Union (EU) Se dietary inclusion rate (0.568 mg of Se/kg of DM) in the form of Se-enriched yeast (SY) derived from a specific strain of Saccharomyces cerevisiae, CNCM I-3060. In a series of studies, dairy cows, beef cattle, calves, and lambs were offered a control diet that contained no Se supplement or a treatment diet that contained the same basal feed ingredients plus a SY supplement that increased total dietary Se from 0.15 to 6.25, 0.20 to 6.74, 0.15 to 5.86, and 0.14 to 6.63 mg of Se/kg of DM, respectively. The inclusion of the SY supplement increased (P < 0.001) whole-blood Se concentrations, reaching maximum mean values of 716, 1,505, 1,377, and 724 ng of Se/mL for dairy cattle, beef cattle, calves, and lambs, respectively. Seleno-methionine accounted for 10% of total whole-blood Se in control animals, whereas the proportion in SY animals ranged between 40 and 75%. Glutathione peroxidase (EC 1.11.1.9) activity was greater (P < 0.05) in SY animals compared with controls. A range of other biochemical and hematological parameters were assessed, but few differences of biological significance were established between treatment groups. There were no differences between treatment groups within each species with regard to animal physical performance or overall animal health. It was concluded that there were no adverse effects on animal health, performance, and voluntary feed intake with the administration of at least 10 times the EU maximum, or approximately 20 times the US Food and Drug Administration permitted concentration of dietary Se in the form of SY derived from a specific strain of Saccharomyces cerevisiae CNCM I-3060.  相似文献   

6.

Background

Selenium (Se) is important for the postnatal development of the calf. In the first weeks of life, milk is the only source of Se for the calf and insufficient level of Se in the milk may lead to Se deficiency. Maternal Se supplementation is used to prevent this.We investigated the effect of dietary Se-enriched yeast (SY) or sodium selenite (SS) supplements on selected blood parameters and on Se concentrations in the blood, colostrum, and milk of Se-deficient Charolais cows.

Methods

Cows in late pregnancy received a mineral premix with Se (SS or SY, 50 mg Se per kg premix) or without Se (control – C). Supplementation was initiated 6 weeks before expected calving. Blood and colostrum samples were taken from the cows that had just calved (Colostral period). Additional samples were taken around 2 weeks (milk) and 5 weeks (milk and blood) after calving corresponding to Se supplementation for 6 and 12 weeks, respectively (Lactation period) for Se, biochemical and haematological analyses.

Results

Colostral period. Se concentrations in whole blood and colostrum on day 1 post partum and in colostrum on day 3 post partum were 93.0, 72.9, and 47.5 μg/L in the SY group; 68.0, 56.0 and 18.8 μg/L in the SS group; and 35.1, 27.3 and 10.5 μg/L in the C group, respectively. Differences among all the groups were significant (P < 0.01) at each sampling, just as the colostrum Se content decreases were from day 1 to day 3 in each group. The relatively smallest decrease in colostrum Se concentration was found in the SY group (P < 0.01).Lactation period. The mean Se concentrations in milk in weeks 6 and 12 of supplementation were 20.4 and 19.6 μg/L in the SY group, 8.3 and 11.9 μg/L in the SS group, and 6.9 and 6.6 μg/L in the C group, respectively. The values only differed significantly in the SS group (P < 0.05). The Se concentrations in the blood were similar to those of cows examined on the day of calving. The levels of glutathione peroxidase (GSH-Px) activity were 364.70, 283.82 and 187.46 μkat/L in the SY, SS, and C groups, respectively. This was the only significantly variable biochemical and haematological parameter.

Conclusion

Se-enriched yeast was much more effective than sodium selenite in increasing the concentration of Se in the blood, colostrum and milk, as well as the GSH-Px activity.  相似文献   

7.
This study measured the effect on glutathione peroxidase (GSH-Px) and selenium (Se) in whole blood and plasma associated with subcutaneous Se injections in beef heifers fed organic or inorganic Se. Heifers (n = 120) were randomly divided into 2 groups, 1 of which received subcutaneous Se injections. Both groups were given the same total mixed ration with 3 mg of organic or inorganic Se daily. Until week 2, heifers that had received Se injections showed higher concentrations of plasma Se and GSH-Px and whole blood Se (P < 0.001) than those having had no injections. Concentrations of plasma Se and GSH-Px were higher in the group receiving organic Se than the group receiving inorganic Se. Whole blood GSH-Px concentrations increased significantly (P < 0.001) throughout a 12-week period but were not affected by Se source. Combination of Se injections and supplementation could help maintain normal Se and GSH-Px blood status in beef heifers during the first few weeks in the feedlot.  相似文献   

8.
ABSTRACT

1. This study was conducted to determine the effect of different sources of selenium (Se) on breast and liver tissue deposition, apparent metabolisable energy (AME), growth performance and antioxidant status of broilers, measured as Se content in liver and breast tissues and glutathione peroxidase (GSH-Px) in blood, when used in 0–35 d broiler chicken diets.

2. A total of 200 male Ross 308 broilers were used in the feeding trial, which comprised two dietary phases, a starter from 0 to 21 d and finisher from 21 to 35 d of age. Four treatments with 10 replications each were used. A control diet (C) was formulated that was sufficient in protein and energy (230 and 215 g/kg of crude protein and 12.67 and 13.11 MJ/kg of metabolisable energy, respectively), for both phases, but contained background Se only from the feed ingredients. Diet 2 (IS) was supplemented with 10.35 g/t inorganic, elemental source of Se. Diet 3 (SY) was supplemented with 136.36 g/t selenised yeast, an organic source derived from Saccharomyces cerevisiae. Diet 4 (SS) was supplemented with 0.666 g/t sodium selenite, an inorganic source.

3. Birds fed the SY diet consumed less and weighed less than those fed IS or C (P < 0.05; 0–35 d of age), but there was no difference compared to birds fed SS diets. There were no differences in FCR or dietary AME between broilers fed different Se sources. All diets containing supplementary Se increased concentrations in the liver and breast muscle, and for GSH-Px levels in blood compared to birds fed the C diet (P < 0.001). Birds fed SY diets had greater Se levels in liver and breast tissues compared to birds fed any of the other diets (P < 0.001).

4. Diets supplemented with Se had variable effects on broiler growth performances and antioxidant status. Feeding Se from a yeast source has higher transfer into breast tissues. Feeding different sources and levels of Se to birds in a more challenging situation to induce oxidative stress may bring more conclusive results.  相似文献   

9.
Fifty Norwegian-bred White Leghorn chickens, 20 weeks of age, were divided into 3 groups and fed a basal diet containing 0.09 mg Se/kg dry matter (D.M.). One group was given a supplement of 0.5 mg Se/kg as seleno-DL-methionine (Se-Met), another group 0.5 mg/kg as sodium selenite while one group served as control. After 10 weeks, all 3 groups were offered the basal diet without added selenium (Se) for a further 9 weeks. At the end of the supplementation period, significantly higher Se levels in blood and tissues were observed in the Se-Met group. These higher levels were not reflected in the glutathione peroxidase (GSH-Px) activity. During the first weeks of the depletion period, there was a steady decrease in Se levels and GSH-Px activity in blood and tissues in both the Se supplemented groups. However, Se levels in the group receiving sodium selenite fell almost to- those in the control group after 2 weeks, while the levels in the Se-Met group did not approach the control levels, even after 9 weeks. There were no differences as regards tissue GSH-Px activity between the 2 supplemented groups, which in both groups nearly reached the control level after 2 weeks. There was, however, a more rapid decrease in GSH-Px activity in whole blood in the sodium selenite group from week 0 to 5 as compared to the Se-Met group. The results obtained in this study support the theory that different forms of Se occupy separate metabolic pools in the body, and that the Se pool resulting from Se-Met supplementation can be mobilized for GSH-Px synthesis in a depletion period.  相似文献   

10.
Our objective was to determine the effect of oil supplementation of pasture fed, beef cattle on the fatty acids, particularly CLA and PUFA, of muscle and s.c. adipose tissue. Forty-five Charolais crossbred heifers were blocked on BW and randomly assigned to 1 of 3 dietary regimens in a randomized complete block design (n = 15). The 3 treatments were: unsupplemented grazing (GO), restricted grazing plus a sunflower oil-enriched ration (SO), or restricted grazing plus a linseed oil-enriched ration (LO). Heifers were fed the experimental diets for approximately 158 d. Samples of LM muscle and s.c. adipose tissue were taken postmortem, the muscle fat was separated into neutral lipid and polar lipid (no separation was performed on the s.c. adipose tissue), and the fatty acid profile was determined by GLC. No effect of dietary treatment on carcass weight or total fatty acid concentration (mean 2,571 mg/100 g of muscle) in muscle fat was detected. Heifers offered SO had a greater (P < 0.001) proportion of CLA and C18:1trans-11 (1.90 and 9.35 vs. 1.35 and 6.89 g/100 g of fatty acids, respectively) in neutral lipid of muscle fat compared with those offered LO, which had a greater proportion of CLA and C18:1trans-11 than heifers offered GO (0.78 and 3.37 g/100 g of fatty acids, respectively). Similar effects were observed in the polar lipid and s.c. lipid. The PUFA:SFA ratio was greater in muscle fat and s.c. adipose tissue from supplemented heifers than in those offered GO (P < 0.001). Compared with LO, the PUFA:SFA ratio was greater (P < 0.05) in muscle fat of heifers offered SO, but there was no difference between SO and LO for this ratio in s.c. adipose tissue. The n-6:n-3 PUFA ratio was similar in muscle and s.c. adipose tissue for GO and LO, but it was greater (P < 0.05) for SO. It is concluded that supplementation of pasture-fed cattle with plant oil-enriched concentrates resulted in an increase in beef fat of some fatty acids considered to be of benefit to human health. Concentrates enriched with sunflower oil were more effective in increasing the CLA concentration, whereas linseed oil-enriched concentrates resulted in a more favorable n-6:n-3 PUFA ratio. The relevance to human health of the associated increase in C18:1trans-11 merits investigation.  相似文献   

11.
Gene expression profiles of LM from beef cattle that underwent significant postweaning undernutrition were studied using complementary DNA (cDNA) microarrays. After 114 d of undernutrition, the RNA from LM showed 2- to 6-fold less expression of many genes from the classes of muscle structural proteins, muscle metabolic enzymes, and extracellular matrix compared with animals on a rapid growth diet. The expression levels of these genes had mostly returned to pretreatment levels after 84 d of realimentation. The gene expression changes associated with undernutrition and BW loss showed an emphasis on downregulation of gene expression specific to fast-twitch fibers, typical of starving mammals, with a preferential atrophy of glycolytic fast-twitch fibers. We also identified a small group of genes that showed 2- to 5-fold elevated expression in LM after 114 d of undernutrition. Putative roles for these genes in atrophying skeletal muscle are regulation of myogenic differentiation (CSRP3), maintenance of mesenchymal stem cells (CYR61), modulation of membrane function (TM4SF2), prevention of oxidative damage (SESN1), and regulation of muscle protein degradation (SQSTM1). A significant increase in stearoyl-CoA desaturase (SCD) gene expression was observed in atrophying muscle, suggesting either that increased fatty acid synthesis is part of the tissue response to caloric restriction, or that SCD plays another role in energy metabolism in the mixed cellular environment of bovine skeletal muscle.  相似文献   

12.
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.  相似文献   

13.
Postmortem proteolysis in skeletal muscle and factors affecting this process were examined in pork, lamb and beef longissimus muscles (LM) to determine the cause of differences in meat tenderness among these species. Fat thickness differed among species in the following order: pork greater than beef greater than lamb. The following patterns were observed for rate of temperature and pH decline: lamb greater than pork greater than beef and pork greater than beef greater than lamb, respectively. At 1 d postmortem, pork was the most tender, followed by beef and lamb, respectively. Between 1 and 14 d of postmortem storage, lamb LM was the most improved in tenderness, followed by beef and pork, respectively. Species did not differ (P greater than .05) in LM collagen solubility. Pork LM from fed pigs had the highest (P less than .05) level of cathepsins B + L and cystatin(s) activities, whereas no differences (P greater than .05) were observed among the species for cathepsin B activity. The lowest (P less than .01) Ca2(+)-dependent protease (CDP)-II and CDP inhibitor activities were observed in pork LM. Beef LM had the highest CDP inhibitor activity (P less than .05) but was intermediate in CDP-II activity. No differences were observed among species for CDP-I activity. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of myofibrils isolated at 0, 1 and 14 d postmortem indicated that by d 1, desmin hydrolysis was most extensive in pork muscle, followed by lamb and beef.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
The distribution of glutathione peroxidase (GSH-Px) activity and selenium concentrations among several components in the blood of dairy cows was examined. Approximately 98% of the GSH-Px activity in peripheral blood was associated with the erythrocytes when enzyme activity was expressed as units per milliliter of blood. The GSH-Px activity expressed per cell was approximately fourfold greater for peripheral leukocytes than for erythrocytes. The cellular component contained a greater proportion (approx 73%) of whole blood selenium than did the plasma. A positive linear relationship (r = 0.958) between blood GSH-Px activity and blood selenium concentrations was found in dairy cattle under practical field conditions.  相似文献   

15.
The present study was designed to assess the balance between antioxidant and prooxidant components and the oxidative stability of beef from cattle fed exclusively grazed pasture (PAS) or a barley-based concentrate offered indoors (CONC) for 11 mo, or fed grass silage indoors for a 5-mo winter period, followed for the remaining 6-mo summer period by grazed pasture (SiP) or by grazed pasture plus concentrate at 50% of the dietary DM (SiPC). Muscle prooxidant and antioxidant components were determined by measuring fatty acids and α-tocopherol concentration of LM, respectively. Lipid oxidation and color stability were monitored in ground LM, packaged in a high-oxygen modified atmosphere, over 11 d of refrigerated storage. Vitamin E concentration decreased (P < 0.0005) with an increasing proportion of concentrate in the diet (2.59, 2.45, 1.76, and 1.15 μg/g for PAS, SiP, SiPC, and CONC, respectively). A greater proportion of PUFA was found in LM from cattle in the PAS, SiP, and SiPC groups compared with animals in the CONC group (9.62, 11.04, 8.96, and 6.94%, respectively; P < 0.0005). A greater concentration of highly peroxidizable PUFA was found in LM from heifers in the PAS, SiP, and SiPC groups compared with those in the CONC group (0.84, 0.85, 0.87, and 0.65 mg/g of muscle, respectively; P = 0.02). Dietary treatment affected lipid oxidation (P < 0.0005), with greater 2-thiobarbituric acid reactive substance values in beef from heifers in the SiPC group than in beef from those in the PAS, SiP, and CONC groups. Dietary treatment affected myoglobin oxidation (P = 0.002) during storage, with greater metmyoglobin accumulation in beef from animals receiving concentrate (CONC and SiPC treatments) than in beef from cattle in the PAS and SiP groups. Consequently, feeding concentrate impaired meat color stability over the storage duration, with greater H* (hue angle) values (P < 0.0005) in meat from heifers in the SiPC and CONC groups compared with meat from those in the PAS and SiP groups. The results of the present study confirm a positive effect of grass-based feeding systems on meat color stability compared with concentrate-based dietary strategies. It appears that vitamin E in muscle alone does not explain the resistance of meat to oxidative deterioration because a clear interaction with highly peroxidizable PUFA exists.  相似文献   

16.
This study was designed to assess the effects of a moderate increase in dietary sulphur (S) in cattle. Twelve animals were initially fed a basal concentrate (S = 0.2%) and then divided into two groups; one fed basal and the other high S (S = 0.75%) concentrates. Health, body weight gains, and activities of erythrocyte enzymes-glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), glucose-6-phosphate dehydrogenase (G6PD), acetylcholinesterase (AChE), plasma- asparate aminotransferase (AST), and whole blood concentrations of selenium (Se) were monitored at various stages of the study. Marked increases in the activities of GSH-Px, SOD and G6PD from the pretrial values were observed upon initial feeding of basal concentrate diet. Sex related differences were not evident in enzyme activities and Se concentrations of the blood. A high linear correlation (r = 0.92) between averages of GSH-Px activity and Se concentration of blood was observed in both sexes. Increasing the amount of S in the concentrate diet (from 0.2 to 0.75%) did not produce any statistically significant change in enzyme activities and Se concentrations, body weight gains, and health of the cattle during the 85 days feeding period. The results indicate that a moderate increase in the dietary S would not impair Se and copper status or cause related disorders in cattle.  相似文献   

17.
Two experiments were conducted to evaluate the effect of dietary Se and Ca on Se utilization in postweaning swine. Two levels of dietary Se (.3 or 5.0 ppm) supplemented as sodium selenite and four levels of total dietary Ca (.50, .80, 1.10 or 1.40%) in a 20% protein, corn-soybean meal diet were evaluated. Inorganic Ca was supplied from dicalcium phosphate and limestone. In Exp. I, 135 pigs weaned at 4 wk of age were allotted by sex, litter and weight and fed a basal diet for 7 d and then their treatment diets for a 28-d period. Plasma and tissue were collected at the end of the trial for Se concentration and glutathione peroxidase (GSH-Px) activity. Dietary Ca had no effect on gain or feed measurements but 5.0 ppm Se depressed daily gain slightly. When 5.0 ppm dietary Se was fed, there resulted higher liver, kidney, heart and longissimus muscle Se concentrations than when .3 ppm was provided, but dietary Ca had no effect on tissue Se values within each dietary Se level. Plasma GSH-Px increased when higher dietary Se was provided, whereas neither heart nor liver GSH-Px activity was affected by dietary Se or Ca level. In Exp. II, a 5-d balance trial was conducted with 32 barrows after adjustment to their treatment diet for a 28-d period. Selenium retention increased quadratically as dietary Ca increased, whereas Ca retention was not affected by dietary Se. These results suggest that low dietary Ca levels may reduce total Se retention but not Se metabolism within body tissue.  相似文献   

18.
A clinical screening procedure was developed for estimating glutathione peroxidase (GSH-Px) activity and selenium status in the blood of dairy and beef cattle. The test is based on the rate of defluorescence under long waveform UV irradiation of reduced nicotinamide adenine dinucleotide phosphate in a coupled enzyme reaction involving glutathione reductase. Defluorescence rates were significantly correlated with blood GSH-Px activity and blood selenium concentrations as determined by conventional laboratory procedures. Blood selenium concentrations and blood GSH-Px activity in several herds were compared with the selenium content of the complete ration consumed to establish reference or base-line values for these blood characteristics under field conditions. The GSH-Px screening procedure provides rapid results, is relatively inexpensive, and appears to be useful in differentiating between the reference values and grossly inadequate selenium status in cattle.  相似文献   

19.
This study was performed to determine the relationship between selenium (Se) content and Se-dependent glutathione peroxidase (GSH-Px) activity in blood and semen, and semen quality of boars at different age used in an artificial insemination (AI) station. Routine macroscopic and microscopic analyses of semen quality were accompanied by measurement of Se content and GSH-Px activity in blood and semen. The Se concentration in blood plasma, seminal fluid and spermatozoa was measured by fluorometric method, the GSH-Px activity by a method based on NADPH-coupled reaction. A total of 155 ejaculates and 58 blood samples were investigated. The results of this study showed that there was no direct relationship between the Se content and GSH-Px activity in blood plasma and semen, and semen quality of sexual matured boars. The mechanisms controlling Se content and GSH-Px activity in blood and semen seem to be independent. The age of boars as a differentiating factor for Se content and GSH-Px activity in blood and semen is possible. It is concluded that a determination of Se status and/or GSH-Px activity in organism before Se supplementation is indicated.  相似文献   

20.
On December 2, 1999, 120 pregnant cows were weighed, their body condition scored, and then sorted into six groups of 20 stratified by BCS, BW, breed, and age. Groups were assigned randomly to six, 5.1-ha dormant common bermudagrass (Cynodon dactylon [L.] Pers.) pastures for 2 yr to determine the effects of supplemental Se and its source on performance and blood measurements. During the winter, each group of cows had ad libitum access to bermudagrass/dallisgrass (Paspalum dilatatum Poir.) hay plus they were allowed limited access (1 to 4 d/wk) to a 2.4-ha winter-annual paddock planted in half the pasture. Treatments were assigned randomly to pastures (two pastures per treatment), and cows had ad libitum access to one of three free-choice minerals: 1) no supplemental Se, 2) 26 mg of supplemental Se from sodium selenite/kg, and 3) 26 mg of supplemental Se from seleno-yeast/kg (designed intake = 113 g/cow daily). Data were analyzed using a mixed model; year was the random effect and treatment was the fixed effect. Selenium supplementation or its source had no effect (P > or = 0.19) on cow BW, BCS, conception rate, postpartum interval, or hay DMI. Birth date, birth weight, BW, total BW gain, mortality, and ADG of calves were not affected (P > 0.20) by Se or its source. Whole blood Se concentrations and glutathione peroxidase (GSH-Px) activity at the beginning of the trial did not differ (P > or = 0.17) between cows receiving no Se and cows supplemented with Se or between Se sources. At the beginning of the calving and breeding seasons, cows supplemented with Se had greater (P < 0.01) whole blood Se concentrations and GSH-Px activities than cows receiving no supplemental Se; cows fed selenoyeast had greater (P < or = 0.05) whole blood Se concentrations than cows fed sodium selenite, but GSH-Px did not differ (P > or = 0.60) between the two sources. At birth and on May 24 (near peak lactation), calves from cows supplemented with Se had greater (P < or = 0.06) whole blood Se concentrations than calves from cows fed no Se. At birth, calves from cows fed seleno-yeast had greater (P < or = 0.05) whole blood Se concentrations and GSH-Px activities than calves from cows fed sodium selenite. Although no differences were noted in cow and calf performance, significant increases were noted in whole blood Se concentrations and GSH-Px activities in calves at birth as a result of feeding of seleno-yeast compared to no Se or sodium selenite.  相似文献   

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