Impact of viral disease hypophagia on pig jejunal function and integrity

PLoS One. 2020 Jan 7;15(1):e0227265. doi: 10.1371/journal.pone.0227265. eCollection 2020.

Abstract

Pathogen challenges are often accompanied by reductions in feed intake, making it difficult to differentiate impacts of reduced feed intake from impacts of pathogen on various response parameters. Therefore, the objective of this study was to determine the impact of Porcine Reproductive and Respiratory Syndrome virus (PRRSV) and feed intake on parameters of jejunal function and integrity in growing pigs. Twenty-four pigs (11.34 ± 1.54 kg BW) were randomly selected and allotted to 1 of 3 treatments (n = 8 pigs/treatment): 1) PRRSV naïve, ad libitum fed (Ad), 2) PRRSV-inoculated, ad libitum fed (PRRS+), and 3) PRRSV naïve, pair-fed to the PRRS+ pigs' daily feed intake (PF). At 17 days post inoculation, all pigs were euthanized and the jejunum was collected for analysis. At days post inoculation 17, PRRS+ and PF pigs had decreased (P < 0.05) transepithelial resistance compared with Ad pigs; whereas fluorescein isothiocyanate-dextran 4 kDa permeability was not different among treatments. Active glucose transport was increased (P < 0.05) in PRRS+ and PF pigs compared with Ad pigs. Brush border carbohydrase activity was reduced in PRRS+ pigs compared with PF pigs for lactase (55%; P = 0.015), sucrase (37%; P = 0.002), and maltase (30%; P = 0.015). For all three carbohydrases, Ad pigs had activities intermediate that of PRRS+ and PF pigs. The mRNA abundance of the tight junction proteins claudin 2, claudin 3, claudin 4, occludin, and zonula occludens-1 were reduced in PRRS+ pigs compared with Ad pigs; however, neither the total protein abundance nor the cellular compartmentalization of these tight junction proteins differed among treatments. Taken together, this study demonstrates that the changes that occur to intestinal epithelium structure, function, and integrity during a systemic PRRSV challenge can be partially explained by reductions in feed intake. Further, long term adaptation to PRRSV challenge and caloric restriction does reduce intestinal transepithelial resistance but does not appear to reduce the integrity of tight junction protein complexes.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Caloric Restriction
  • Eating / physiology*
  • Host-Pathogen Interactions / physiology
  • Intestinal Mucosa / cytology
  • Intestinal Mucosa / metabolism
  • Intestinal Mucosa / physiopathology*
  • Jejunum / cytology
  • Jejunum / metabolism
  • Jejunum / physiopathology*
  • Porcine Reproductive and Respiratory Syndrome / physiopathology*
  • Porcine Reproductive and Respiratory Syndrome / virology
  • Porcine respiratory and reproductive syndrome virus / isolation & purification
  • Porcine respiratory and reproductive syndrome virus / pathogenicity*
  • Sus scrofa
  • Swine
  • Tight Junction Proteins / metabolism
  • Tight Junctions / metabolism

Substances

  • Tight Junction Proteins

Grants and funding

Funding for this research was provided by the Agriculture and Food Research Initiative Competitive Grant #2016-67015-24574 (awarded to NKG) and the USDA National Institute of Food and Agriculture National Needs Fellowship program (support of E. T. Helm’s graduate studies).