Influence of different methods of slaughtering on the release and/or retention of neurotransmitter and other biomolecules at neuromuscular junction

Abstract

We have investigated acetylcholinesterase (AChE) and related biochemical parameters in different edible parts of chicken expected to be influenced by the techniques of slaughtering. Chickens were slaughtered using sharp knife: necks were either cut off completely (C) or partially (P) with complete or no damage to spinal cord respectively; and immediately after slaughtering, body was either released (R) or held tied (T) until the animal died. Traditional practices of slaughtering of chicken or other domestic animals involve the use of a knife. Aim of the study is to identify possible physiological and biomolecular changes during slaughtering which varies in the mentioned parameters. Acetylcholine (Ach) is a major neurotransmitter (NT) in neuromuscular junction (NMJ) of vertebrate, release of which is related to muscle movement and blood removal; but due to its very short lifespan, it is actually measured indirectly by measuring the enzyme AChE. No significant differences were observed in AChE activity in muscles taken from chickens slaughtered in four different ways. The expression of AChE mRNA was found to be lower in muscles from chickens that were slaughtered by cutting their necks off partially (P) and released immediately after slaughtering (PR), compared to the other three combinations of slaughtering i.e., CR, PT and CT. Differences in the conditions of slaughtering i.e. in neck cutting and/or releasing of body immediately after slaughtering do not affect the Hb concentration and the amount of Zn and Fe either in muscle or liver, deducing no significant difference in blood loss due to different type of slaughtering. Total protein profile of muscle sample, from 2D-PAGE showed promising band differences between different slaughtering methods which verify possible protein expression variation due to different slaughtering. Protein spot identified as spot no.1 showed an expression difference between slaughtering technique PR and CT; in CT, it has been expressed near pH 5.0 and MW 116 although in PR it was not been expressed. Similarly, spot no 2 in CR, expressed near pH3.0 and between Mw of 25-35 showed an average of 2.8 fold increase in intensity compare to PT. Protein spot no 1 has similar position with previously identified AChE band, therefore it has high possibility of being the AChE protein. In that case, protein expression of AChE mimics mRNA expression of it.