Sows Seropositive to Lawsonia intracellularis (LI) Influence Performance and LI Seropositivity of their Offspring

Abstract

The aim of the study was to test, if seropositivity to L. intracellularis does decline more rapidly in the offspring of Lawsonia intracellularis (LI) positive gilts than in the offspring of LI negative gilts in units infected with endemic Porcine Proliferative Enteropathy (PPE). In a Croatian pigproduction unit late-pregnant gilts were tested by an indirect immunofluorescence antibody (IFA) serum assay for LI. Twenty IFA-positive and 20 IFA-negative gilts were selected. Their 2-weekold piglets (191 from positive gilts, and 192 from negative gilts) were inoculated intragastrically with pure-culture of LI. These animals were tested until 25 weeks of age for seroprevalence of LI. Blood samples were collected at 5, 10, 15, 20 and 25 weeks of age.Seropositivity in offspring of IFA negative gilts was highest at the age of 5 weeks (85.9%) and declined gradually from week 10 to only 6.3% at week 25. At the same time, the offspring of IFA positive gilts showed lower and faster-decaying seroprevalence: 21.4% at week 5 and 0% at weeks 15, 20, and 25. There was no significant difference in the occurrence of diarrhoea between the offspring of LI seropositive and seronegative gilts. Mortality was significantly (p < 0.05) higher (20.4%) among offspring of seronegative, compared to 14.1% the offspring of seropositive gilts. Average weight gains were higher (p < 0.05, 741 ± 44g vs. 611 ± 41g⋅d -1 ) among the offspring of seropositive than among of seronegative gilts. The essence of this report is the observation that seropositivity to LI declines more rapidly in grower/finisher pigs born to LI seropositive gilts than the ones born to LI seronegative gilts in units infected with endemic PPE.

Advances in Ileitis Control, Diagnosis, Epidemiology and the Economic Impacts of Disease in Commercial Pig Herds

“…The progeny of 20 seropositive and 20 seronegative gilts were challenged with L. intracellularis at two weeks of age and remained suckling for an additional three weeks. Only 21% of piglets on seropositive gilts had L. intracellularis antibodies three weeks post challenge, relative to 86% of piglets from seronegative gilts [112].…”

“…The detection of L. intracellularis in the feces of a small number of suckling pigs in endemically-infected herds has led researchers to speculate that sows may be a source of infection to their piglets [108,112,113]. However, the detection of antibodies to L. intracellularis in three to six week old pigs, and the occurrence of PE predominantly in pigs greater than six weeks of age [32], suggests that piglets are more likely protected from L. intracellularis by either antibodies or lymphocytes from the sow in colostrum or later by IgA in milk.…”