The Effects of Dietary Selenium Level and Source on Selenium The Effects of Dietary Selenium Level and Source on Selenium Retention in Two Blood Components in SwineRetention in Two Blood Components in Swine

Jessica C. Solomon, Dr. Donald C. MahanDepartment of Animal Sciences, The Ohio State University, Columbus, OH

Introduction

Objectives

Procedures and Methods

Results and Conclusions

Resources

Acknowledgments

Selenium (Se) is an essential micro mineral for swine that is required in the diet to maintain optimal physiological function. Its natural availability in local forage and grains is dependent on soil concentrations with most areas in the US demonstrating a Se deficiency (Ullrey, 1980). To prevent deficiency within the animal, dietary supplementation of Se becomes a necessary measure to insure animal health in production practices. Deficiencies and toxicities (> 5 ppm Se) can adversely affect the general health of the herd. This is evident through lowered

To determine what effect dietary selenium has on red blood cell and plasma Se retention through a comparison of the

Time over which the diet is fed

Level of selenium concentration in the diet

Source of selenium in the diet

Selenium Concentration in Red Blood Cells

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

35 53 88

Time (Days)

Se C

once

ntra

tion

in u

g/m

L (p

pm)

0.3 ppm Organic Se

3.0 ppm Organic Se

3.0 ppm Inorganic Se

Selenium Concentration in Plasma

0

0.1

0.2

0.3

0.4

0.5

0.6

35 53 88

Time (Days)

Se C

once

ntra

tion

in u

g/m

L (p

pm)

0.3 ppm Organic Se3.0 ppm Organic Se3.0 ppm Inorganic Se

Averages of Selenium Concentration in Red Blood Cells and Plasma for Each Diet GroupNursery (35 Days) Grower (53 Days) Finisher (88 Days)

Se Diet (ppm) RBC Plasma % Se RBC Plasma % Se RBC Plasma % Se0.3 Organic 0.265 0.134 52.4 0.294 0.164 59.9 0.336 0.210 67.03.0 Organic 0.898 0.372 42.7 1.518 0.488 35.6 1.611 0.497 35.13.0 Inorganic 0.781 0.386 41.3 1.056 0.510 52.1 1.409 0.409 30.2

immune response, impaired reproductive efficiency of the breeding stock, and slow growth rate (NRC, 1998). It becomes paramount to provide the animals with a level of Se supplementation that is nutritionally adequate but yet below the feeding level that can produce negative effects and

Ten gilts were allotted to one of three diet groups for a total of thirty subjects. The dietary Se level of these diets met (0.3 ppm) or exceeded requirements ten fold (3.0 ppm).

The control diet contained 0.3 ppm organic Se. The experimental diet and positive control diet contained 3.0 ppm organic Se and 3.0 ppm inorganic Se, respectively.

Organic Se was added to the diets in the form of an organic yeast containing Se (Sel Plex) while inorganic Se was added in the form of sodium selenite.

Effect of Time

Se concentration in the RBC increased with increasing time from the Nursery to the Grower and to the Finisher production stages. (Figure 2)

Effect of Level: 0.3 ppm Se vs. 3.0 ppm Se

At higher levels of Se supplementation there was a greater increase in RBC Se concentration than was found in the plasma. (Figure 2, Figure 3)

Effect of Source: Organic vs. Inorganic Selenium

The RBC Se concentration for the organic diet (3.0 ppm) was greater than the inorganic diet (3.0 ppm) which demonstrated that organic Se was retained more readily by the RBC than the inorganic form. (Figure 2)

These conclusions are supported by existing selenium research in swine nutrition that has shown that both the source and level of Se supplementation effects the concentration of Se in different blood components (Kim and Mahan, 2001). Acute toxicity studies have also suggested that the ability of the RBC to retain organic selenium more efficiently than inorganic forms may lead to a reduction in the toxic effects of selenosis (Kim and Mahan, 2001).

Frank Cihla, Research Associate; James Jolliff, Graduate Research Associate; Matthew Roy; Ken Mays and the staff at the OSU Swine Center

The level of supplementation as well as the source of selenium in the pigs’ diets affected the retention and concentration of selenium found in the blood

components (RBC and plasma) over time.

Figure 1

Figure 2

Figure 3

Future Research

What possible effects would long term Se supplementation at the 3.0 ppm organic level yield in swine?

How would such effects manifest physically in regards to RBC and plasma Se concentration?

Blood was collected at 35, 53, and 88 days corresponding to the nursery, grower, and finisher stages of production . Blood samples were centrifuged at 2200 x g at 4°C and separated into components (RBC and plasma). Each component was analyzed for selenium by fluorometric method of AOAC (2005).

Individual Se concentration values within each diet group and production stage were averaged. The % difference in Se concentration between RBC and plasma values was calculated (Figure 1 reports these results).

Kim, Y.Y. and D.C. Mahan. “Comparative effects of high dietary levels or organic and inorganic selenium on selenium toxicity of growing-finishing pigs.” Journal of Animal Sciences. 79 (2001):942-948 pp.

(NRC) National Research Council Subcommittee on Swine Nutrition. Nutrient Requirements of Swine: 10th Revised Edition. (1998). 2 Mar. 2009 <http://books.nap.edu/openbook.php?record_id=6016&page=R1>

Ullrey, Duane E. “Regulation of Essential Nutrient Additions to Animal Diets (Selenium – A Model Case.” Journal of Animal Sciences. 51 (1980): 645-651 pp.

--- “Biochemical and Physiological Indicators of Selenium Status I Animals.” Journal of Animal Sciences. 65 (1985): 1712-1726 pp.

which has been termed selenosis. Today in the US, the FDA regulated amount of selenium that may be added to the diet of all pigs is 0.3 ppm (NRC, 1998). This level of supplementation has been determined to be adequate in preventing deficiency symptoms in the majority of swine herds.