Asian-Aust. J. Anim. Sci. Vol. 19, No. 7 : July 2006

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1 984 AsianAust. J. Anim. Si. Vol. 19, No. 7 : July Effets of Spent Composts of Seleniumenrihed Mushroom and Sodium Selenite on Plasma Glutathione Peroxidase Ativity and Selenium Deposition in Finishing Hanwoo Steers S. H. Lee, B. Y. Park 1, Sung S. Lee 2, N. J. Choi 1, J. H. Lee, J. M. Yeo, J. K. Ha 3, W. J. Maeng 4 and W. Y. Kim* Department of Animal Siene, Korea National Agriultural College, RDA, Suwon , Korea ABSTRACT : Effets of spent omposts of seleniumenrihed mushroom (SeSMC) on plasma glutathione peroxidase (GSHPx) ativity and selenium (Se) deposition in finishing Hanwoo (Bos taurus oreanae) steers were investigated. Twentyfive Hanwoo steers (average body weight = 613 kg, average age = 22 months) were allotted to treatments in five groups of five steers per pen for 12 weeks preeding slaughter. Treatments were SMC alone (CON; 0.1 ppm Se), 0.3 ppm (0.3 SeSMC), 0.6 ppm (0.6 SeSMC), 0.9 ppm (0.9 Se SMC), and 0.9 ppm (sodium selenite; SENI) Se. During the experimental period, blood samples were taken to analyze Se onentrations and GSHPx ativities. Musle and liver samples were olleted for analyses of Se ontents after slaughter. Dry matter intake and body weight gain were not affeted by SeSMC or sodium selenite supplementation. Selenium onentration in the whole blood and GSHPx ativity in plasma were linearly inreased (p<0.01) with inreasing levels of SeSMC. The whole blood Se onentration of SENI treatment was signifiantly higher (p<0.05) than that of CON treatment from 4 weeks, whereas there was no signifiant differene in GSHPx ativities between both treatments at 8 and 12 weeks. Selenium ontent in the hind leg and liver inreased linearly (p<0.05) with inreasing levels of SeSMC, but those of SENI treatments were not signifiantly different from CON treatments. These results suggested that Se in the SeSMC was highly bioavailable to blood and tissues of ruminants, espeially ompared with Se in the sodium selenite. Therefore, SeSMC might be used not only as an inexpensive way of providing Se for ruminants but also as another way of produing Sefortified beef. (Key Words : Spent Composts of SeEnrihed Mushroom, Sodium Selenite, Glutathione Peroxidase, Selenium Deposition, Hanwoo Steers) INTRODUCTION It has been well known that selenium (Se) plays an important role in ellular antioxidant defense system of living tissues (Gerloff, 1992), in whih the Seontaining antioxidant enzyme glutathione peroxidase (GSHPx) is responsible for atalyzing the deomposition of lipid hydroperoxides into lessreative produts (Rotruk et al., 1973; Han et al., 2004). More reently, it has been reported that adequate or supranutritional levels of Se intake ould * Corresponding Author: W. Y. Kim. Tel: , Fax: , wykim@rda.go.kr 1 National Livestok Researh Institute, RDA, Suwon , Korea. 2 Division of Applied Life Siene, Gyeongsang National University, RAIRC, Jinju, , Republi of Korea. 3 Shool of Agriultural Biotehnology, Seoul National University, Seoul , Korea. 4 Nutrition Bank Researh Institute, Seoul , Korea. Reeived Otober 18, 2005; Aepted January 19, 2006 not only derease inidenes of tumors in humans (Clark et al., 1996), but also alleviate risks of many diseases assoiated with Se (Rayman, 2000). For these reasons, some animal nutritionists have made attempts to aumulate Se into animal produts suh as meat, milk and egg by supplementing dietary Se soures in the feed (Ortman and Pehrson, 1999; Lawler et al., 2004; Payne et al., 2005). In their studies, supplementation of inorgani Se suh as sodium selenite or sodium selenate to animal feed showed onsiderable limitations in the intestinal absorption and retention of the animal tissues. In ontrast, organi Se has been found to be an effetive form to enhane Se ontents in animal produts (Mahan and Parrett, 1996; Ortman and Pehrson, 1999). Selenized yeasts generally used as an organi Se soure are effiient in inreasing Se ontents in the animal produts, but prie is the limitation sine they are relatively expensive. In previous studies, by utilizing the Seaumulating property of mushroom (Van Elteren et al., 1998), Se

2 Lee et al., (2006) AsianAust. J. Anim. Si. 19(7): Table 1. Chemial ompositions of spent omposts of mushrooms Item Moisture (g) CP 1 (g) CF 2 (g) EE 3 (g) CA 4 (g) NFE 5 (g) Se (mg) kg 1 DM 8 SeSMC SMC Crude protein. 2 Crude fiber. 3 Ether extrat. 4 Crude ash. 5 Nitrogenfree extrat. 6 Spent mushroom omposts from Seenrihed mushroom. 7 Spent mushroom omposts from normal mushroom. 8 Dry matter. Table 2. Ingredients and hemial ompositions of the experimental diets Item Treatments CON 0.3 SeSMC 0.6 SeSMC 0.9 SeSMC SENI Ingredient omposition (DM basis) SeSMC 1 (%) SMC 1 (%) Corn grain (%) Barley grain (%) Corn gluten meal (%) Tall fesue straw (%) Barley bran (%) Molasses sugarane (%) Sodium selenite 2 (mg/kg) Vitamin/mineral mix 3 (%) Chemial omposition (DM basis) Dry matter (%) Crude protein (%) Crude fiber (%) Ether extrat (%) Crude ash (%) Nitrogenfree extrat (%) Calium (%) Phosphorus (%) Selenium (mg/kg) TDN 4 (%) See Table 1. 2 Sodium selenite was purhased from sigma hemials. 3 Consisted of Ca 15%, P 6.8%, Mg 7.0%, Na 7.8%, Zn 5,000 mg/kg, Mn 4,000 mg/kg, Cu 500 mg/kg, I 300 mg/kg, Co 20 mg/kg, Se 0 mg/kg, vitamin A 400,000 IU/kg, vitamin D 3 75,000 IU/kg, and vitamin E 500 mg/kg. 4 TDN value was alulated aording to the regression equation desribed by Wardeh (1981). enrihed mushroom and spent mushroom omposts (SMC) were produed when sodium selenite as an inorgani Se soure was added to mushroom omposts. It was proven that spent mushroom omposts (SeSMC) ontained onsiderable amounts of Se mainly as the organi form (Lee et al., 2005). Therefore, it was hypothesized that the supplement of SeSMC as a nononventional feed would not only produe Sefortified beef but also redue feed ost. In the present study, effets of SeSMC in omparison with sodium selenite on plasma GSHPx ativity and Se deposition in finishing Hanwoo (Bos taurus oreanae) steers were determined. MATERIALS AND METHODS Preparation of spent mushroom omposts and experimental design The SMC was obtained from two different mushroom farms where Seenrihed and normal mushrooms of the same speies (Flammulina velutipes) were ultivated under the same growth ondition. Seleniumenrihed mushroom is produed by supplementing inorgani Se as sodium selenite (2 mg Se per kg omposts on the fresh basis) in the omposts, while normal mushroom is produed by the onventional method without the supplement of sodium selenite. After about a 60d period of mushroom growth, both the SMCs were transported into Hanwoo attle farm (loated at Chonnam provine of Korea) to be utilized as a feed ingredient of experimental diets. Chemial ompositions of eah SMC from Seenrihed and normal mushrooms are presented in Table 1. Steers were assigned randomly to one of five treatments (n = 5 per treatment): SMC alone (CON; 0.1 ppm Se), 0.3 ppm (0.3 SeSMC), 0.6 ppm (0.6 SeSMC), 0.9 ppm (0.9 SeSMC) Se, and 0.9 ppm (sodium selenite; SENI). The total of 25 finishing Hanwoo steers (average body weight = 613 kg, average age = 22 months), as similar as possible in age and body weight, were allotted to treatments in five

3 986 Lee et al., (2006) AsianAust. J. Anim. Si. 19(7): Table 3. Effets of SeSMC and sodium selenite on dry matter intake and body weight of Hanwoo steers Item Treatments CON 0.3 SeSMC 0.6 SeSMC 0.9 SeSMC SENI SE 1 Signifiane Period of feeding DM intake (kg/head/d) 1 to 30 d NS 31 to 60 d NS 61 to 90 d NS Overall NS (BW gain) Total BW gain (kg) NS ADG 2 (g) NS NS: Not signifiant. 1 Pooled standard error. 2 Average daily gain. groups of five steers per pen. Eah diet was fed to steers in an individual gate feeding system. Experimental diets, feeding, and management Ingredients and hemial ompositions of the experimental diets are presented in Table 2. Exept for the sodium selenite treatment, other experimental diets were formulated to ombine SMC with SeSMC in order to adjust the levels of Se in the diets. For the sodium selenite treatment, sodium selenite was dissolved in distilled water (0.9 mg Se/kg feed, DM basis) and then added to ontrol diet (CON). Selenium ontents in the treatment diets were within the range of expeted onentrations, and CP and TDN ontents (on DM basis) were similar among treatments as shown in Table 2. Thus, diets were isoalori and isonitrogenous among treatments. The nutritional levels of experimental diets were determined on the basis of the offiial Korean feeding standard for Hanwoo beef attle (MAF and NLRI, 2002). Due to the high onentration of moisture for SMC, the diets were formulated on the yle of 2 weeks period to prevent unfavorable fermentation. The experimental diets were stored in the polyethylene vinyl envelope with m size in order to keep anaerobi ondition until fed to animals. Diets were analyzed for Se ontent to make sure that they ontained the appropriate Se levels for eah treatment after formulated and paked. All steers were onformed to the experimental environment and experimental diets for 2 weeks period in whih steers were gradually swithed from a onventional diet to the experimental diet and the main feeding trial was subsequently performed for 12 weeks. Treatment diets were provided for ad libitum intake twie daily at 07:00 and 19:00 h, and water was allowed to be aessible freely through the automati water provider. The water ontained undetetable onentration of Se (<2 ng/ml). Daily dry matter intake was reorded by the differene between the supply and ort amounts, and initial and final body weights for all animals were measured to observe body weight gain on the daily basis throughout the experimental period. At the end of the experimental period, all animals were slaughtered in the slaughterhouse (National Agriultural Cooperative Federation, Chonnam, Korea) for olletion of tissues from hind leg (m. trieps surae) as a skeletal musle and liver as a high metaboli organ for Se. Sample olletion and analytial methods Eah treatment diet was sampled after manufatured and analyzed for nutritional omponents aording to AOAC (1995). Blood samples were olleted from the jugular vein into 10ml heparinized tubes (Vautainer tube, BetonDikinson, In., NJ, USA) at 2, 4, 8 and 12 weeks after feeding for the measurements of whole blood Se onentration and GSHPx ativity in plasma. Blood samples for whole blood Se analyses were frozen at 75 C and freezedried. Blood samples for GSHPx ativity were immediately entrifuged (1,500 g for 15 min) to obtain plasma, whih was stored at 75 C until analyses. A ut of about 1 kg from the hind leg and liver taken from slaughtered animals was thoroughly mined, freezedried, and kept at 75 C until analyses. With the hind leg tissue, subutaneous adipose tissues were removed to analyze total Se ontent. Selenium analyses for all samples (diets, whole blood and tissues) were determined by the fluorometri method of AOAC (1995). For more detail proedure of Se analysis, all samples lyophilized were ignited and digested in the oxygensaturated ombustion flask (ELJEE glass manufaturer, Seoul, Korea) with nitri aid (70%, Sigma Aldrih, USA). The ph for digested samples was adjusted to 2±0.2 using ammonium hydroxide (Sigma Aldrih, USA). After the addition of 2,3diaminonaphthalene (Sigma Aldrih, USA), the samples were plaed at room temperature for about 2 h to allow the formation of piazselenol omplex. Plaed samples were transferred into a separator funnel and the piazselenol omplex in samples was extrated by shaking after the addition of ylohexane (Sigma Aldrih, USA). The fluoresene of the extrated omplex was measured with the exitation wavelength set at 375 nm and emission wavelength at 520 nm. The samples ompleted the analytial preparation were assayed in a fluoresene spetrophotometer (PerkinElmer Model 204, USA) equipped with xenon power supply (PerkinElmer

4 Lee et al., (2006) AsianAust. J. Anim. Si. 19(7): Table 4. Effets of SeSMC and sodium selenite on the plasma GSHPx ativity of Hanwoo steers Item Treatments CON 0.3 SeSMC 0.6 SeSMC 0.9 SeSMC SENI GSHPx ativity (unit) 2 2 weeks b a a b 4 weeks b b a a a 8 weeks b b a a b 12 weeks b b a a b ** p<0.01 and *** p< a, b, Means in a row with different supersripts differ signifiantly (p<0.05). 1 Pooled standard error. 2 One unit of glutathione peroxidase (GSHPx) ativity equals 1 µmol of NADPH oxidized per min/ml of plasma SE 1 Signifiane *** ** *** *** Whole blood Se (ng/ml) b b a b d a b d a b d a b Inst. In., Cary, NC, 2000). Dependent variables were dry matter intake, performanes (body weight gains), Se onentration in whole blood, plasma GSHPx ativity, and Se ontents of tissues. The model inluded treatments (df = 4) and steers within the treatment (df = 4). Steers within the treatment were used as error terms to test effets of treatments. Signifiant differenes among treatments were determined by Dunan s multiple range test at a level of p<0.05 (Steel and Torrie, 1980) Time after feeding (wk) Figure 1. Effets of SeSMC and sodium selenite supplement on the whole blood Se onentrations in Hanwoo steers. Legend: CON (open bar), 0.3 SeSMC (solid bar), 0.6 SeSMC (rosshathed bar), 0.9 SeSMC (diagonal bar), and SENI (blok bar). a, b,, d Within eah feeding time, bars with different letters are signifiantly different (p<0.05). Vertial bars represent standard error. Model 150, USA). The GSHPx ativity in plasma was assayed by the oupled enzymati method of Lawrene and Burk (1976) by utilizing hydrogen peroxide and umene hydroperoxide as substrates. The medium mixture for GSHPx assay onsisted of 10 mm GSH, 2 mm NADPH, 10 mm EDTA, 10 mm sodium azide, glutathione redutase (10 unit per milliliter), 500 mm potassium phosphate and distilled water. The mixture was inubated at 25 C for 5 min before the addition of 500 times diluted plasma. After the addition of substrate and diluted plasma to the mixture, GSHPx ativity was assayed in the spetrophotometer (Shimadzu, Japan) with the kineti funtion. The absorbane at 340 nm was reorded for 3 min at 10 se intervals. The ativity was defined as miromoles of NADPH oxidized per minute and per milliliter of plasma. Statistial analysis Statistial analysis for all dependent variables was performed as a ompletely randomized design using the general linear model of SAS program (Version 8.1; SAS RESULTS AND DISCUSSION Daily dry matter intake and body weight gain Either SeSMC or sodium selenite supplementation to the diets did not affet DM intakes for Hanwoo steers throughout the trial (Table 3). The present result agreed with Rok et al. (2001) and Gunter et al. (2003), who reported that organi (0.3 and 26 ppm, respetively) or inorgani (0.3 and 26 ppm, respetively) Se supplementation in the diets of gestational ewes or beef attle did not affet feed intakes. Dietary Se levels applied for the present study did not result in any sign of selenosis, suh as hair loss, separation of the hoof, respiratory failure and so on, as desribed in NRC (1996). Even though it has been known to be toxi in the dietary Se level from 5 to 20 ppm in swine, resulting in dereased ADG and feed intake (Kim and Mahan, 2001), the toxi level of dietary Se for attle has not been well defined until now. Hintze et al. (2002) reported that a ration ontaining more than 10 ppm of Se for beef steers did not influene feed intake and show any toxi symptoms. It an be assumed that ruminants might be more tolerable for Se toxiity than monogastris. Therefore, the highest level of Se (0.9 ppm) in the SeSMC and SENI treatments of the present study was relatively safe in terms of steer health. In addition, total BW gain and ADG of Hanwoo steers during the experimental period were not affeted by Se SMC or SENI (Table 3). Numerous studies investigated to determine effets of dietary Se soures or levels on the Se transfer to tissue for fortifiation and prevention of Se defiieny in the animals. Of those studies, Lawler et al. (2004) reported that when beef steers were provided diets

5 988 Lee et al., (2006) AsianAust. J. Anim. Si. 19(7): with 0.38 or 2.8 ppm of Se using the highse wheat and sodium selenate, the high levels of dietary Se did not affet ADG, feed effiieny, and DMI. Likewise, Hintze et al. (2002) reported no differenes in performanes (feed intake, ADG and final body weight) between steers finished (105 d) on either 0.62 or 11.9 ppm of Se in the diet of highse hay and wheat mix. Those studies were in aordane with results from the present study, showing that the highest level of dietary Se (0.9 ppm) did not adversely affet the performanes of finishing beef steers. Blood measurements Whole blood Se onentrations of Hanwoo steers were signifiantly inreased with enhaning levels of SeSMC and the supplement of SENI in the diets (p<0.01; Figure 1). The signifiant differenes of whole blood Se onentrations aross the treatments were learly noted with inreasing levels of SeSMC. Between the two types (Se SMC and sodium selenite) of treatments with 0.9 ppm Se, the whole blood Se onentration of SeSMC was signifiantly higher than that of the sodium selenite group (p<0.05). As the supplement period lasted, Se onentrations of the SeSMC groups were remarkably inreased, whereas that of the sodium selenite group was less remarkable. The inrease of whole blood Se onentration by inreasing levels of Se from SeSMC was aomplished within 2 weeks and subsequently reahed a plateau after 4 weeks. These results were similar to those from Ortman and Pehrson (1999), who reported that the supplement of different Se soures in the diet of dairy ows elevated the whole blood Se levels within 2 weeks, in whih selenized yeast onsisting of mainly selenomethionine as the organi Se form showed a muh higher level for whole blood Se than the inorgani Se, suh as sodium selenite and selenate. Thus, it an be assumed that Se present in SeSMC is exellent in the intestinal absorption and the main hemial form of Se present in SeSMC is likely to be a moleular form of Se organially bound to the myelium protein, showing that the whole blood Se onentration of SeSMC treatment was muh higher than that of sodium selenite treatment at the same Se level in the diet. In the present study, lower Se onentration in the whole blood of sodium selenite treatment seemed that most of the sodium selenite fed by steers was exreted into fees. In ruminants, organially bound Se in the diet is known to be more effetive in the intestinal absorption and Se aumulation in tissues than inorgani Se soures (van Ryssen et al., 1989). Previous studies have found that a onsiderable amount of inorgani Se is formed as insoluble selenide in the rumen, subsequently exreted into fees (Peterson and Spedding, 1963; Wright and Bell, 1966). Meanwhile, Lee et al. (2005) reported that approximately 70% of Se present in SeSMC from Seenrihed mushrooms used in this experiment was organi Se. Stefánka et al. (2001) also demonstrated that inorgani Se added to mushroom ompost was onverted to organi Se and their predominant form of Se was mostly selenoystine. However, Se distribution among different moleular forms for mushroom speies and its SMC used in this experiment has not been determined. In the present study, even though GSHPx ativities in plasma were less altered ompared with the hanges of whole blood Se onentrations, GSHPx ativities for groups supplemented with SeSMC were generally higher than those of CON treatments (p<0.01; Table 4). Signifiant differenes in the plasma GSHPx ativities among treatments began to be deteted within 2 weeks. After the supplementation period of 4 weeks, steers fed diet ontaining 0.3 ppm Se (0.3 SeSMC) showed slightly higher GSHPx ativities ompared to those of CON treatments, but did not signifiantly differ. On the other hand, GSHPx ativities from 0.6 and 0.9 SeSMC groups were muh higher than those from the CON and 0.3 Se SMC groups (p<0.05), but signifiant differene for GSH Px ativity was not observed between 0.6 and 0.9 SeSMC treatments. Overall, whole pattern for GSHPx moved upward as dietary Se levels inreased, indiating that plasma GSHPx ativities were ontrolled by the dietary Se ontent. Even though GSHPx ativity of SENI treatment was signifiantly inreased ompared to that of the CON treatment until 4 weeks, its signifiane between both treatments was not observed in the period of 8 and 12 weeks. Glutathione peroxidase ativities, a physiologially funtional form of Se, have been proposed as the best estimate of Se status for human or animal (Stevens et al., 1985; Smith et al., 1988). Gunter et al. (2003) reported that supplement of Seenrihed yeast or sodium selenite inreased GSHPx ativity of ows ompared with no Se supplemented group. Similarly, Hintze et al. (2002) fed beef steers with a different bakground (seleniferous or nonseleniferous areas) either 11.9 or 0.62 mg of Se/kg of diet as highse hay and wheat mix, and they found that the inreased GSHPx ativity was shown in the steers fed the highse diet throughout the feeding trial, regardless of the bakground. Therefore, proportional inreases for GSHPx ativities of SeSMC treatments observed in these experiments seem to be losely related with the inreased blood Se onentration by supplementing SeSMC ontaining a high proportion of organi Se. However, in spite of the signifiant inrease for whole blood Se onentration of SENI treatment ompared to that of CON treatment at 8 and 12 weeks, no signifiant differene regarding GSHPx ativities between CON and SENI was found. The present results were similar to those of Enjalbert

6 Lee et al., (2006) AsianAust. J. Anim. Si. 19(7): Table 5. Effets of SeSMC and sodium selenite on selenium deposition in musular and hepati tissues Item Treatments CON 0.3 SeSMC 0.6 SeSMC 0.9 SeSMC SENI SE 1 Signifiane Tissue Se (µg/g of dry weight) Hind leg ab ab a b * Liver b a *** * p<0.05 and *** p< a, b, Means in a row with different supersripts differ signifiantly (p<0.05). 1 Pooled standard error. et al. (1999) and Rowntree et al. (2004), who reported that supplement of inorgani Se as sodium selenite inreased plasma Se onentration, but plasma GSHPx ativity was not affeted. On the other hand, it ould be explained that the signifiant differene for GSHPx ativity between CON and SENI treatments at 2 and 4 weeks might be attributable to the inrease of whole blood Se onentration in SENI treatment ompared to CON treatment. Therefore, one annot rule out the possibility that the selenite supplement may temporarily inrease plasma GSHPx ativity with inreasing whole blood Se onentration during the early phase of selenite supplement. However, sine plasma GSH Px is a shortterm indiator of Se status and 98% of GSH Px ativity is assoiated with erythroytes (Sholz and Huthinson, 1979), GSHPx ativity of erythroytes might be further eluidated. Meanwhile, the possible reason for no signifiant differene for the ativity of GSHPx between CON and 0.3 SeSMC after 4 weeks seems to be due to marginal blood Se onentration in order to express the adequate ativity of GSHPx. As shown in Figure 1, the whole blood Se onentrations for 0.6 and 0.9 SeSMC treatments started from 4 weeks were maintained more than 180 ng/ml whih is known to be an adequate level (160 to 1,200 ng/ml) for optimal GSHPx ativity and immune funtion (Puls, 1989), whereas blood Se onentrations in CON and 0.3 SeSMC treatments showed marginal levels (60 to 150 ng Se/mL; Puls, 1989). Thus, it an be oneived that in the present study, marginal points of whole blood Se onentration ated as a limiting fator for the expression of adequate GSHPx ativity. However, in an investigation with swine by Mahan et al. (1999), a narrow range of Se onentrations with 0.05, 0.1, 0.2 or 0.3 ppm in the diet even inreased GSHPx ativity quadratially ompared with the basal diet over a whole period. One annot rule out the possibility that suh a result might be due to speies speifiity between ruminants and monogastris. Even though it ould not be shown inreases of GSHPx ativities at a low Se level (CON vs. 0.3 SeSMC), possibly due to the low Se level in plasma and/or speies speifiity, it was learly shown that GSHPx ativities at the higher levels of Se (0.6 and 0.9 SeSMC) were inreased, possibly resulting in benefiial effets on animal health. Se deposition in tissues As the level of SeSMC was inreased, Se ontents in the hind leg and liver were linearly inreased (p<0.05), but those of SENI treatments were not signifiantly different ompared with CON treatments (Table 5). Selenium ontents in the hind leg and liver were the highest in the 0.9 SeSMC group, followed by those in 0.6 SeSMC, 0.3 Se SMC, SENI, and CON treatments (p<0.05). These results showed that Se deposition in the tissue inreased with enhaning levels of Se as the form of SeSMC. However, taken aount into Se intakes among treatments, the rate of Se retention in the skeletal musle was lower than expeted. Hintze et al. (2001) reported that in ruminants, skeletal musle Se had a stronger assoiation (r = 0.66) with whole blood Se, thus Se onentration of whole blood was the best preditor for that of skeletal musle. Similarly, results from the present study showed that musular Se onentration was proportionally inreased with enhaning Se levels in the diet as the form of SeSMC. Many studies have reported that the feeding of organi soures suh as Seenrihed yeasts and some forages or grains from seleniferous regions during the defined period enabled animals to inrease blood Se onentration and to aumulate Se in their tissues (van Ryssen et al., 1989; Kim and Mahan, 2001; Lawler et al., 2004). The Se speiation for SeSMC used in the present study was not determined. However, a high proportion of organi Se in SeSMC as desribed in the previous report (Lee et al., 2005) ould explain the signifiant inrease of Se deposition in the skeletal musle of Hanwoo beef steers. Selenium onentration in the musle was similar to the result of Hintze et al. (2002) utilized the same Se level (approximately 0.6 ppm) in the diet as the present study. On the other hand, Se onentration in the liver remarkably inreased with supplementing SeSMC. These results were similar to the data provided by Combs and Combs (1986), whih reported that Se onentration in the liver was around four times higher than that in the skeletal musle. The present data indiated that Se onentration in the liver was up to maximally four folds inreased ompared with the CON treatment. The inreasing onentration of Se in the liver by supplemental SeSMC level showed the same pattern as skeletal musle. High Se onentration in the liver ompared with musle might result from the fat that liver ats as a major pool of Se in the body.

7 990 Lee et al., (2006) AsianAust. J. Anim. Si. 19(7): In ontrast, Se inrement in the musle by feeding Se SMC was relatively low as minimum 35% to maximum 68% ompared with SeSMC unsupplemented group. Lawler et al. (2004) reported that when highse hay or wheat diet with supranutritional level of Se was fed to beef steers, Se onentration in the musle showed tremendously inreased value ompared with the ontrol or sodium selenate groups, suggesting that dietary level and hemial form of Se are ruial fators to produe high Se beef. However, Hintze et al. (2002) reported that the transfer of dietary Se to musle was ineffiient as maximum of 2.6%. Meanwhile, the World Health Organization (1996) reported that the reommended daily allowane (RDA) of Se for adults was 40 µg. In the present study, it was alulated that, on the fresh basis of the highest Se ontent (0.9 SeSMC treatment) for the hind leg (30.88% DM), 100 g of the beef ontained approximately µg Se, providing approximately 35.3% Se of the RDA. The above results showed that inorporation of SeSMC into the diet ould be easy and inexpensive way to inrease Se onentration in the body of beef steers, but sodium selenite was ineffiient in the view of intestinal absorption and deposition of Se. In onlusion, based on the health benefits of Se by the reports of Clark et al. (1996) and Rayman (2000), it would be expeted that Se onentrations inreased in beef by supplementing SeSMC to Hanwoo steers ould ontribute to human health by providing more Se. ACKNOWLEDGMENTS This trial was supported by a grant from the Speial Grants Researh Program of the Ministry of Agriulture and Forestry (Grant No SB010). REFERENCES AOAC Offiial Methods of Analysis. 16th ed. Assoiation of Offiial Analytial Chemists, Washington, DC. 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