1. The Effects of Dietary Selenium Level and Source on SeleniumThe 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. Mahan
Department 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)
SeConcentrationinug/mL(ppm)
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)
SeConcentrationinug/mL(ppm)
0.3 ppm Organic Se
3.0 ppm Organic Se
3.0 ppm Inorganic Se
Averages of Selenium Concentration in Red Blood Cells and Plasma for Each Diet Group
Nursery (35 Days) Grower (53 Days) Finisher (88 Days)
Se Diet (ppm) RBC Plasma % Se RBC Plasma % Se RBC Plasma % Se
0.3 Organic 0.265 0.134 52.4 0.294 0.164 59.9 0.336 0.210 67.0
3.0 Organic 0.898 0.372 42.7 1.518 0.488 35.6 1.611 0.497 35.1
3.0 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.