Evaluation of stress hormone (cortisol) levels and some biochemical parameters of pigs kept under intensive management systems in Morogoro, Tanzania
The worldwide increase in demand for animal products in recent decades has necessitated raising of food animals under intensive systems that have been demonstrated to cause stress to animals. A cross sectional study was carried conducted to evaluate the welfare of pigs kept under intensive system using serum cortisol levels and some biochemical parameters as indicators of stress. A total of 302 pigs, aged three months to two years, from urban and peri-urban areas of Morogoro township were purposively involved in the study which assessed farm management aspects (housing and feeding) and blood levels of cortisol and some biochemical parameters (glucose, total protein and cholesterol). Results showed that serum cortisol levels were significantly higher (p < 0.001) in pigs from the peri-urban farms than those dwelling in the urban settings. Weaner pigs and boars had the highest serum cortisol levels compared to other groups. Significantly high levels of plasma cholesterol (p < 0.05) were measured in boars followed by gilts and weaners all kept in the urban areas whereas no significant differences were observed as far as plasma glucose and total proteins were concerned. Result on farm management assessment showed that urban piggery housing was of better quality than in the peri-urban and that feeding was largely influenced by local availability of the major feed ingredients such as maize bran and vegetable residues. About 80% of urban pigs were maintained on high concentrate feed due to availability of swills (restaurant leftovers) and maize bran whereas low concentrate feed with mainly vegetable residues dominated in the peri-urban settings. It is concluded that, serum cortisol levels observed in the current study were a reflection of stress to different groups of pigs kept under the intensive system and that feeds had some direct effect on biochemical parameters such as plasma cholesterol levels.
Key words: Stress factors, biochemical parameters, cortisol, pigs, urban, peri-urban