IPVS 2016 - Using the acute phase protein Pig-MAP in diagnosing Ileitis

In a monitoring program finishing pigs at a farm were found positive for PRRS and Ileitis at the end of finishing. Pigs at the involved farm (7000 finishing pig places, Topigs 20 x Topie, boars & gilts) were vaccinated against PCV2 and Mycoplasma. Pleurisy and pneumonia were below the slaughterhouse average. Technical performance was lower than the Dutch average (ADG of 750 vs 796 gram/day). Pigs showed a growth depression in the grower period, but without clinical symptoms like respiratory problems and/or diarrhea which made it hard to select acute phase representatives for post mortem examination. To get more insight in the cause the use of acute phase proteins and antibody seroconversion during the growth depression phase were combined.

In total 5 consecutive week groups were selected for measuring the acute phase protein Pig-MAP using a commercial Elisa (PigCHAMP-Pro). The first week group was the group of pigs one week before showing the first signs of the growth depression, at 3 weeks of finishing. The subsequent week groups were at 4, 5 and 7 weeks of finishing, showing signs of growth depression. The last selected group was at 8 weeks of finishing, and were recovering. Of each week group, 20 pigs were randomly selected and 7 ml of blood was collected by jugular venapunture. After the analysis of Pig-MAP, 10 serum samples from week group 5 and 6, and 15 samples from week group 8 were selected for seroconversion against PRRS (Idex herdcheck Elisa) and ileitis (Bioscreen Illeitis Elisa).

Pig-MAP was considered normal in the samples of week group 3 (0.59 mg/ml, sd 0.20 mg/ml). Subsequent week groups 4,5,7 and 8 showed a raise in Pig-MAP concentrations with means of 0.79 (SD 0.29), 0.81 (SD 0.29), 0.89 (SD 0.29) and 1.14 (SD 0.83) mg/ml respectively. All the selected serum samples for PRRS-analysis were positive with a mean S/P ratio of 2.11 (ranging from 1.09 until 2.69), indicating earlier infections before the observed growth depression. Seroconversion due to ileitis however, was in line with the observed growth depression. Positive samples were increasing from week group 5 until 8 (# negative/ # inconclusive/ # positive samples): group 5: (8/0/2); group 7: (5/2/3); group 8: (2/3/10). The raise of positive samples was in line with the raise of Pig-MAP concentrations per week group.

Using a combination of measuring growth depression, the use of the acute phase protein Pig-MAP and antibody seroconversion, made it possible to differentiate between PRRS and ileitis. Ileitis is the most plausible cause of the growth depression.

Disclosure of Interest: None Declared