Date of Award

2012

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Fisheries, Animal and Veterinary Science

First Advisor

Katherine H. Petersson

Abstract

Gastrointestinal parasitism in sheep, particularly lambs, results in substantial economic losses to producers worldwide. Nutritional status has been shown to play an important role in host immune response to parasitic infections. The objective of this study was to investigate the effect of vitamin E supplementation on an artificial Haemonchus contortus (H. contortus) infection in immature lambs. Twenty Dorset lambs were stratified into two treatment groups according to parasite susceptibility. Worm-free lambs, 28 to 32 weeks of age, were supplemented with vitamin E (d-α-tocopherol) for twelve weeks following the recommendations of the National Research Council for minimal daily requirement (VE5; 5.3 IU/kg body weight (BW)/day (d), n=10) or optimal immune function (VE10; 10 IU/kg BW/d, n = 10). Five weeks after initiation of vitamin E supplementation, lambs were infected with 10,000 H. contortus L3 larvae. Samples were taken weekly for determination of fecal egg counts (FEC), packed cell volume (PCV), and serum α-tocopherol. After six weeks of infection, the lambs were humanely slaughtered for the determination of tissue vitamin E content, worm burden and histologic evaluation of the abomasum. Increased dietary vitamin E supplementation had no effect on liver (P=0.08), muscle (P=0.62), or lymph node (P=0.38) α-tocopherol content. There was no effect of treatment on FEC or PCV, however there was a 49% reduction in total abomasal worm burden (P=0.002) in the VE10 group. These results indicate that elevated levels of vitamin E supplementation had a beneficial effect on the abomasal worm burden; however, there was no treatment effect on PCV or FEC.

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