Porinas as an adyuvant of inactivated Newcastle vaccine in broilers

Abstract

Three groups of 25 broilers were vaccinated on two opportunities by aerosol using inactivated NC (Newcastle) virus and different helper concentrations of porinas (20 ìg, 50 ìg, 125 ìg). A fourth group was injected with live B1 virus (12 and 28 days of age) nasally. The NC inactivated virus (La Sota strain) was concentrated 10 times with PEG with a final titer of 1:2.056. Twenty serums for each group were taken in order to evaluate NC antibodies using the HI and double immuno-difusion tests for IgA detection at 1, 12, 28 and 42 days of age. During the study the chickens were on a restricted diet in order to control ascites (2.640 mosl). On day 42, two broilers of the fourth group (live virus) presented ascites and 1 broiler of group 1 presented lung edema (20 ìg). The geometric mean for NC antibodies titers at 42 days of age was 2 in the groups 1,2,3 and 5.7 in the group 4 (Log 2). For IgA, 180 mg/dl, 135 mg/dl, 120 mg/dl and 176 mg/dl respectively. Three broilers of each group were challenged with a pathogenic strain of NC, at 42 day of age, without signs of disease after 72 hours when the positive control group was dead. Gross and microscopic lesions were not detected in the bursa of Fabricius or thymo. [thymo sounds like short hand for something that should be properly named.] Very good animal weight, conversion and efficiency results were observed in all the groups. New studies using a fixed dose of porinas, larger numbers of broilers and the establishment of protective levels of IgA against NC challenge are recommended.