Vitamin E supplementation does not mitigate the acute morbidity effects of porcine reproductive and respiratory syndrome virus in nursery pigs.
The objective of this study was to determine whether feeding a vitamin E-rich diet would benefit nursery pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV). Sixty-four pigs were subjected to one of four treatment combinations (2 x 2 factorial) of dietary vitamin E (adequate or excess) and PRRSV (medium or inoculation with VR-2385 isolate P-129). Pigs were fed experimental diets during a 3-wk period before inoculation as well as during a 12-d period after inoculation. Growth performance was determined throughout the study, and lipid peroxidation in liver, glutathione peroxidase (GPX) activity in serum, circulating white blood cells, and serum interleukin-1beta (IL-1beta) and interferon-gamma (IFN-gamma) were determined in samples collected from pigs killed 4 or 12 d after inoculation. Infection by PRRSV (P < 0.001) induced a marked decrease in both ADFI and ADG, but neither the main effect of diet nor the diet x PRRSV interaction was significant. Neither diet nor PRRSV affected feed efficiency. At 12 d after inoculation, lipid peroxidation in liver and GPX activity in serum were lower in pigs fed excess vitamin E than in those fed adequate vitamin E (P < 0.01), suggesting that the diet high in vitamin E bolstered the antioxidant status of the pigs. However, PRRSV did not affect lipid peroxidation in liver or serum GPX activity, and the diet x PRRSV interaction was not significant. White blood cell counts were decreased and IFN-gamma, and IL-1beta were increased (P < 0.05) 4 and 12 d after inoculation in PRRSV-infected pigs, but neither diet nor the diet x PRRSV interaction was significant. Collectively, these results indicate that increasing antioxidant defenses by feeding high levels of vitamin E did not ameliorate the effects of PRRSV on decreased growth, leukopenia, and increased serum IL-1beta and IFN-gamma. Thus, feeding nursery pigs a diet high in vitamin E may not be useful for mitigating the acute morbidity effects of PRRSV infection.
Department of Animal Sciences, University of Illinois, Urbana, IL 61801, USA.
T L
TL
Toepfer-Berg
J
J
Escobar
W G
WG
Van Alstine
D H
DH
Baker
J
J
Salak-Johnson
R W
RW
Johnson
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage* / Q000627:therapeutic use; D016207:Cytokines / Q000097:blood*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects; D005260:Female; D005979:Glutathione Peroxidase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000201:enzymology; D008297:Male; D019318:Porcine Reproductive and Respiratory Syndrome / Q000097:blood / Q000276:immunology / Q000401:mortality* / Q000517:prevention & control; D019316:Porcine respiratory and reproductive syndrome virus / Q000472:pathogenicity; D011897:Random Allocation; D013552:Swine / Q000097:blood / Q000254:growth & development* / Q000276:immunology; D014810:Vitamin E / Q000008:administration & dosage* / Q000627:therapeutic use; D015430:Weight Gain
D000975:Antioxidants; D016207:Cytokines; D014810:Vitamin E; D005979:Glutathione Peroxidase