The tissue compatibility of different Mycoplasma hyopneumoniae vaccines is mainly dependent upon their adjuvants.

Abstract

Aim of this study was to investigate the tissue compatibility of three differently adjuvated Mycoplasma hyopneumoniae vaccines. Local tissue reactions after an intramuscular injection of 2 ml doses of Stellamune Mycoplasma (oil-adjuvated; Pfizer, Karlsruhe, Germany) and Suvaxyn M.hyo (carbopol-adjuvated; Fort Dodge, Würselen, Germany) were examined in suckling and weaned piglets.The different effects of the injection volumes of 1 ml and 2 ml of the vaccine M+PAC (aluminium hydroxide- and oil-adjuvated; essex tierarznei, Munich, Germany) on the tissue compatibility were assessed in weaned piglets. All animals were euthanized 6 days post vaccination. Clinical investigation of the injection sites revealed a slight to moderate increase in tissue consistency, a mild increase of local skin temperature, as well as a mild reddening of the skin in both age groups four hours after the application of all vaccines. Concerning gross pathological and histological changes, most prominent changes were noted following vaccination with the M+PAC vaccine. However, the other two vaccines also induced mostly mild pathoanatomical changes at the injection sites. Histologically, Stellamune Mycoplasma caused a slight degeneration of muscle fibres and invasion of macrophages, whereas Suvaxyn M.hyo additionally led to a moderate necrosis and the appearance of giant cells. The dual-action-adjuvated vaccine M+PAC induced severe necrotic lesions and vacuoles. In addition, the degree of tissue reaction appeared to be related to the size of the administered volume. In general, the age of the animals seemed to be of minor importance concerning the quality of the tissue reactions.