Progress 01/01/06 to 06/30/08
Outputs
OUTPUTS: The objective of this study was to determine the effects of Se deficiency on respiratory chain complex activities, protein expression, and protein oxidation in growing beef cattle consuming Se adequate and deficient diets.Twelve beef calves (210 kg ea) were weaned from the SWREC cow herd and placed on a 2.5-ha pasture seeded to oats and ryegrass and managed to promote an average daily gain of 1 kg for 140 days (140 kg of total BW gain). The pasture was sampled monthly to monitor N, detergent fibers, and mineral concentrations in the forage. Three days weekly, heifers were fed 1 kg/aninmal of ground corn containing a mineral supplement containing no supplemental Se (n=6), or 3 mg of Se from selenomethionine (n=6). At the beginning (day 0) and 140 days, muscle tissue will be obtained through an incision through skin exposing the gluteus maximus using the point of the scapula. Using a biopsy needle, tissue were obtained and placed in a labeled cryogenic vial, capped, and flash frozen in liquid N until analysis. Also, during the grazing period, calves were weighed every 28 days and bled to determine whold blood Se and GPx activity in the erythrocytes. On 27 January 2006, the production part of this project was started and was completed by 2 of June. Body weight and ADG did not differ (P was greater or equal to 0.54) between treatments; however, the WBSe tells a different story. After the initial feeding of the supplement, WBSe was greater (P is less or equal to 0.04) in supplemented calves from March 1 until June 2. By the ending of the trial, the difference in WBSe was 79 ng/mL and the No Se treatment was well below any estimate of adequacy as we attempted to produce. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Supplementation of grazing stocker cattle on winter-annual pasture with organic Se increases whole blood Se concentration. The organic Se is more effective at supplementing cattle with Se than sodium selenite. This information has given state livestock specialist knowledge of the selenium status of cattle grazing winter-annual on the Costal Plain region of Arkansas and how beef cattle producers can manage deficiencies. Also, this research has shown that unsupplemented cattle will be depleted to a point that immunocompetence is more than likely.
Publications
- No publications reported this period
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Progress 01/01/07 to 12/31/07
Outputs
Normally, grazing cattle are fed a generalized trace mineral mixture stylized for many regions of the US. Research from the SWREC has shown that cattle can become Se deficient even when supplemented at the FDA limit of 26 mg/animal daily with sodium selenite. In preliminary studies conducted in the winter of 2003 at the SWREC growing cattle grazing winter annual pasture did not have adequate Se intake to maintain adequate WBSe concentrations and decreases quadraticly (P < 0.01) across days. Beginning in November, WBSe was 173 ng/mL; however, by May the WBSe concentrations had decreased by 83 percent to 29 ng/mL. The WBSe reported in December are suggested to be acceptable (60 to 150 ng Se/mL) for optimal GPx activity and immune function, but in May the WBSe was well below any estimate of adequacy. During this same grazing period, muscle tissue collected from the gluteus maximus showed a dramatic decline in Se concentration. Between November and May, the Se
concentration decreased 76 percent (P < 0.01; 169 to 41 ng/g, respectively). Se deficiency in cattle has been shown to cause myodegeneration via oxidative damage. In a study using Japanese quail, day old chicks were fed either Se deficient (0.05 ppm) or a Se supplemented (1.5 ppm) diets. After 30 d, the quail were sacrificed and mitochondria were isolated from their liver and heart tissue. In both tissues, there was a 30 to 70 percent decrease in the cytochrome c oxidase activity with quail fed the Se deficient diets. The dietary Se concentration in the low Se diet fed was 12 percent greater that the Se concentrations in forage offered to cattle grazing at the SWREC (0.04 mg/kg). To date there is evidence that the antioxidant system, where Se plays a significant role, protects the cellular membranes. Furthermore, there is evidence that animals on a Se deficient diet have impaired mitochondrial function; however, we know of no current research involving mitochondria from any livestock
species. With Y2006 funding from the AES Animal Health funds, the first half of the previously mentioned project was initiated. On 27 January 2006, the production part of this project was started and was completed by 2 of June. Body weight and ADG did not differ (P is greater or equal to 0.54) between treatment; however, the WBSe tells a different story. After the initial feeding of the supplement, WBSe was greater (P is less or equal to 0.04) in supplemented calves from March 1 until June 2. By the ending of the trial, the difference in WBSe was 79 ng/mL and the No Se treatment was well below any estimate of adequacy as we attempted to produce. We have harvested 2 sets of the necessary muscle tissue samples from the previously mentioned cattle and the samples have been stored in liquid nitrogen and are ready for analysis.
Impacts
Supplementation of grazing stocker cattle on winter-annual pasture with organic Se increases whole blood Se concentration. The organic Se is more effective at supplementing cattle with Se than sodium selenite.
Publications
- No publications reported this period
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Progress 01/01/06 to 12/31/06
Outputs
Normally, grazing cattle are fed a generalized trace mineral mixture stylized for many regions of the US. Research from the SWREC has shown that cattle can become Se deficient even when supplemented at the FDA limit of 26 mg/animal daily with sodium selenite. In preliminary studies conducted in the winter of 2003 at the SWREC growing cattle grazing winter annual pasture did not have adequate Se intake to maintain adequate WBSe concentrations and decreases quadraticly (P < 0.01) across days. Beginning in November, WBSe was 173 ng/mL; however, by May the WBSe concentrations had decreased by 83% to 29 ng/mL. The WBSe reported in December are suggested to be acceptable (60 to 150 ng Se/mL) for optimal GPx activity and immune function, but in May the WBSe was well below any estimate of adequacy. During this same grazing period, muscle tissue collected from the gluteus maximus showed a dramatic decline in Se concentration. Between November and May, the Se concentration
decreased 76% (P < 0.01; 169 to 41 ng/g, respectively). Se deficiency in cattle has been shown to cause myodegeneration via oxidative damage. In a study using Japanese quail, day old chicks were fed either Se deficient (0.05 ppm) or a Se supplemented (1.5 ppm) diets. After 30 d, the quail were sacrificed and mitochondria were isolated from their liver and heart tissue. In both tissues, there was a 30 to 70% decrease in the cytochrome c oxidase activity with quail fed the Se deficient diets. The dietary Se concentration in the low Se diet fed was 12% greater that the Se concentrations in forage offered to cattle grazing at the SWREC (0.04 mg/kg). To date there is evidence that the antioxidant system, where Se plays a significant role, protects the cellular membranes. Furthermore, there is evidence that animals on Se deficient diet have impaired mitochondrial function; however, we know of no current research involving mitochondria from any livestock species. With Y2006 funding from the
AES Animal Health funds, the first half of the previously mentioned project was initiated. On 27 January 2006, the production part of this project was started and was completed by 2 of June. Body weight and ADG did not differ (P ≥ 0.54) between treatment; however, the WBSe tells a different story. After the initial feeding of the supplement, WBSe was greater (P ≤ 0.04) in supplemented calves from March 1 until June 2. By the ending of the trial, the difference in WBSe was 79 ng/mL and the No Se treatment was well below any estimate of adequacy as we attempted to produce. We have harvested 2 sets of the necessary muscle tissue samples from the previously mentioned cattle and the samples have been stored in liquid nitrogen and are ready for analysis.
Impacts
Supplementation of grazing stocker cattle on winter-annual pasture with organic Se increases whole blood Se concentration. The organic Se is more effect at supplementing cattle with Se than sodium selenite.
Publications
- Gunter, S. A., et al. 2006. Selenium, zinc, and copper accumulation in growing cattle grazing winter pasture on the coastal plain. J. Anim. Sci. 84(Suppl. 2):37. (Abstr.).
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