Dependence of the histomorphological structure of m. Longissimus thoracis in fattening pigs from the method of their castration and live weight
Abstract
The article investigated the dependence of the histological structure of m. Longissimus thoracis muscle in immunocastrated pigs vaccinated with the “Improvak” vaccine from the company “Zoetis”, USA, and in non-castrated pigs fattened under the conditions of industrial pork production and slaughtered at different live weights. For the study, two experimental groups of 220 gilts each were formed, derived from Irish Landrace and Irish Yorkshire sows and inseminated with semen from boars of the MakGro synthetic line. At the age of 72 days, with an average live weight of 26 kg, they were brought to a fattening farm where the piglets of the research group were vaccinated on the 112th day of life with the vaccine “Improvak” from the company “Zoetis”, USA, in a quantity of 2 ml. They were re-vaccinated on the 148th day of life with the same vaccine and in the same quantity. The pigs in the control group were not castrated. It was found that in m. Longissimus thoracis muscle of immunocastrated pigs using the “Improvak” vaccine, the diameter of the muscle fibres decreased by 15 micrometres and the fibres absorbed more sarcoplasm, which, against the background of a 14 % increase in the content of parenchymal components, indicates an increase in the juiciness and tenderness of the meat. It has been shown that the muscle fibres of the longissimus thoracis no longer grow as a result of the immunocastration of pigs, but take on useful properties, i.e. become hydrated and fat. It was found that pre-slaughter weight had no significant effect on the histological parameters of the longest back muscle of the pigs studied.
Keywords
