Biol Trace Elem Res (2014) 161:308–317 DOI 10.1007/s12011-014-0134-1
Effect of Selenium Yeast Supplementation on Naturally Acquired Parasitic Infection in Ewes Kathryn J. Hooper & Gerd Bobe & William R. Vorachek & Janell K. Bishop-Stewart & Wayne D. Mosher & Gene J. Pirelli & Michael L. Kent & Jean A. Hall
Received: 17 August 2014 / Accepted: 17 September 2014 / Published online: 26 September 2014 # Springer Science+Business Media New York 2014
Abstract Gastrointestinal parasites cause substantial economic losses in pasture-based sheep production systems. Supranutritional organic selenium (Se) supplementation may be beneficial because it improves immune responses to pathogens. To evaluate the effect of Se-yeast supplementation on gastrointestinal parasite load, 30 ewes per treatment group were drenched weekly with no Se, 4.9 mg Se/week as Se yeast (maximum FDA-allowed concentration), or supranutritional concentrations of Se yeast (14.7 and 24.5 mg Se/week) starting early fall for 85 weeks. Fecal samples were collected at weeks 63, 66, 78, and 84 and counted for total trichostrongyle-type eggs and Haemonchus contortus eggs (in samples with ≥200 trichostrongyle eggs/g feces). During breeding season (fall), ewes were kept on pasture; ewes receiving 24.5 mg Se/week had lower fecal trichostrongyle egg counts (93±40 eggs/g feces) compared with ewes receiving no Se (537±257 eggs/g feces; P=0.007) or ewes receiving 4.9 mg Se/week as Se yeast (398±208 eggs/ g feces; P=0.03). In winter, fecal trichostrongyle egg counts decreased, and group differences were not apparent. During lambing season (spring), ewes were kept in the barn and fecal trichostrongyle egg counts increased, although no
group differences were observed. However, none of the ewes receiving supranutritional Se yeast, and with trichostrongyle egg counts ≥200 eggs/g of feces, but four of the ewes receiving lower Se dosages had H. contortus egg counts ≥1,000 eggs/g feces (P = 0.04). Our results suggest that supranutritional Se-yeast supplementation may enhance resistance to naturally occurring H. contortus gastrointestinal parasitism in sheep.
K. J. Hooper : W. R. Vorachek : J. K. Bishop-Stewart : M. L. Kent : J. A. Hall (*) Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Dryden Hall 206, Corvallis, OR 97331-4802, USA e-mail: [email protected]
Introduction
G. Bobe : W. D. Mosher : G. J. Pirelli Department of Animal and Rangeland Sciences, College of Agriculture, Oregon State University, Corvallis, OR 97331-4802, USA G. Bobe Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-4802, USA
Keywords Gastrointestinal parasites . Haemonchus contortus . Selenium-yeast supplementation . Sheep Abbreviations GI Gastrointestinal FDA Food and Drug Administration ICP-MS Ionized coupled plasma mass spectrometry IQR Interquartile range PBS Phosphate-buffered saline Se Selenium WB Whole blood
Gastrointestinal (GI) parasites are a major cause of production losses in pasture-based sheep systems worldwide [1]. For example, GI parasites are estimated to cost the UK sheep industry about £84 million annually and the Australian sheep industry 222 million dollars annually [2, 3]. The cost to the sheep industry in Canada and the USA, including Oregon, is currently unknown [1]. Economically, the most damaging GI nematode in sheep throughout much of the USA, including Oregon, is the barber pole worm (Haemonchus contortus), which is a blood-sucking abomasal worm [4]. We recently presented results on the prevalence of H. contortus (JKB, 59th
Selenium Yeast and Parasite Infection in Ewes
Annual Meeting of the American Association of Veterinary Parasitologists, Denver, CO, July 2014). Prevalence of H. contortus in sheep and cattle has been increasing in Oregon, Washington, and California from 71 % in 2011 to 2012 to 83 % in 2013 to 2014. The disorder haemonchosis is caused by severe H. contortus infection with H. contortus fecal egg counts ≥2,000 eggs/g feces [5]. The animals also have trichostrongyle fecal egg counts ≥10,000 eggs/g feces, as mixed infections with other GI parasites are common [5]. Animals that have been recently weaned are the most vulnerable to H. contortus infection, becoming anemic, failing to thrive, and often they die. Bottle jaw, caused by hypoproteinemia, is a classic sign of infection, along with loss of body condition, weakness, and rough appearance, with or without diarrhea [6]. Haemonchosis is diagnosed using the following criteria: H. contortus counts ≥2,000 eggs/g feces, measuring packed cell volume to document anemia, larval culture, and necropsy [7]. Mild to moderate H. contortus infection is also diagnosed by the presence of H. contortus eggs in the feces [8], although trichostrongyle and H. contortus egg counts are much lower than fecal egg counts required for haemonchosis. This is more commonly seen with chronic infections in mature ewes [7]. Animal production and performance parameters are still compromised with H. contortus
Effect of Selenium Yeast Supplementation on Naturally Acquired Parasitic Infection in Ewes Kathryn J. Hooper & Gerd Bobe & William R. Vorachek & Janell K. Bishop-Stewart & Wayne D. Mosher & Gene J. Pirelli & Michael L. Kent & Jean A. Hall
Received: 17 August 2014 / Accepted: 17 September 2014 / Published online: 26 September 2014 # Springer Science+Business Media New York 2014
Abstract Gastrointestinal parasites cause substantial economic losses in pasture-based sheep production systems. Supranutritional organic selenium (Se) supplementation may be beneficial because it improves immune responses to pathogens. To evaluate the effect of Se-yeast supplementation on gastrointestinal parasite load, 30 ewes per treatment group were drenched weekly with no Se, 4.9 mg Se/week as Se yeast (maximum FDA-allowed concentration), or supranutritional concentrations of Se yeast (14.7 and 24.5 mg Se/week) starting early fall for 85 weeks. Fecal samples were collected at weeks 63, 66, 78, and 84 and counted for total trichostrongyle-type eggs and Haemonchus contortus eggs (in samples with ≥200 trichostrongyle eggs/g feces). During breeding season (fall), ewes were kept on pasture; ewes receiving 24.5 mg Se/week had lower fecal trichostrongyle egg counts (93±40 eggs/g feces) compared with ewes receiving no Se (537±257 eggs/g feces; P=0.007) or ewes receiving 4.9 mg Se/week as Se yeast (398±208 eggs/ g feces; P=0.03). In winter, fecal trichostrongyle egg counts decreased, and group differences were not apparent. During lambing season (spring), ewes were kept in the barn and fecal trichostrongyle egg counts increased, although no
group differences were observed. However, none of the ewes receiving supranutritional Se yeast, and with trichostrongyle egg counts ≥200 eggs/g of feces, but four of the ewes receiving lower Se dosages had H. contortus egg counts ≥1,000 eggs/g feces (P = 0.04). Our results suggest that supranutritional Se-yeast supplementation may enhance resistance to naturally occurring H. contortus gastrointestinal parasitism in sheep.
K. J. Hooper : W. R. Vorachek : J. K. Bishop-Stewart : M. L. Kent : J. A. Hall (*) Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Dryden Hall 206, Corvallis, OR 97331-4802, USA e-mail: [email protected]
Introduction
G. Bobe : W. D. Mosher : G. J. Pirelli Department of Animal and Rangeland Sciences, College of Agriculture, Oregon State University, Corvallis, OR 97331-4802, USA G. Bobe Linus Pauling Institute, Oregon State University, Corvallis, OR 97331-4802, USA
Keywords Gastrointestinal parasites . Haemonchus contortus . Selenium-yeast supplementation . Sheep Abbreviations GI Gastrointestinal FDA Food and Drug Administration ICP-MS Ionized coupled plasma mass spectrometry IQR Interquartile range PBS Phosphate-buffered saline Se Selenium WB Whole blood
Gastrointestinal (GI) parasites are a major cause of production losses in pasture-based sheep systems worldwide [1]. For example, GI parasites are estimated to cost the UK sheep industry about £84 million annually and the Australian sheep industry 222 million dollars annually [2, 3]. The cost to the sheep industry in Canada and the USA, including Oregon, is currently unknown [1]. Economically, the most damaging GI nematode in sheep throughout much of the USA, including Oregon, is the barber pole worm (Haemonchus contortus), which is a blood-sucking abomasal worm [4]. We recently presented results on the prevalence of H. contortus (JKB, 59th
Selenium Yeast and Parasite Infection in Ewes
Annual Meeting of the American Association of Veterinary Parasitologists, Denver, CO, July 2014). Prevalence of H. contortus in sheep and cattle has been increasing in Oregon, Washington, and California from 71 % in 2011 to 2012 to 83 % in 2013 to 2014. The disorder haemonchosis is caused by severe H. contortus infection with H. contortus fecal egg counts ≥2,000 eggs/g feces [5]. The animals also have trichostrongyle fecal egg counts ≥10,000 eggs/g feces, as mixed infections with other GI parasites are common [5]. Animals that have been recently weaned are the most vulnerable to H. contortus infection, becoming anemic, failing to thrive, and often they die. Bottle jaw, caused by hypoproteinemia, is a classic sign of infection, along with loss of body condition, weakness, and rough appearance, with or without diarrhea [6]. Haemonchosis is diagnosed using the following criteria: H. contortus counts ≥2,000 eggs/g feces, measuring packed cell volume to document anemia, larval culture, and necropsy [7]. Mild to moderate H. contortus infection is also diagnosed by the presence of H. contortus eggs in the feces [8], although trichostrongyle and H. contortus egg counts are much lower than fecal egg counts required for haemonchosis. This is more commonly seen with chronic infections in mature ewes [7]. Animal production and performance parameters are still compromised with H. contortus
