Detection of Cocaine and Amphetamine Regulated Transcript in the abomasum of slaughtered bulls with different daily body weight gains

Abstract

Despite numerous published studies, the relationship between the amount of secreted cocaine and amphetamine regulated transcript and the daily body weight gain has still not been well explained. The aim of this study was to determine the incidence of cocaine and amphetamine regulated transcript in the outlet wall of the abomasum of bulls with different daily weight gains. The study was performed on 15 bulls, breed crosses of local black and white milk cattle and Limousin bulls. The animals were slaughtered at the mean age of 543–549 days and body weight of 441.0–491.4 kg. Fragments of the outlet wall of the abomasum were sampled for analyses during routine slaughter. Immunohistochemical assays showed that slowly growing bulls (803 g/day) had significantly (P ≤ 0.05) fewer positive structures of cocaine and amphetamine regulated transcript (by 1.65 × on average) compared to bulls with large daily weight gains (905 g/day). This tendency was also observed in the case of cocaine and amphetamine regulated transcript distribution in particular layers of the abomasum wall. The most numerous positive structures of cocaine and amphetamine regulated transcript were found in the nerve fibres of the muscularis and in the muscle plexus, whereas they were evidently less numerous in the submucous plexus. Our results suggest that the number of cocaine and amphetamine regulated transcript immunopositive structures is associated with the growth intensity of the animals, and frequent occurrence of this neuropeptide in the nerve fibres and the muscular plexus proves its role in the control of stomach emptying.