TIME AND DOSE-DEPENDENT INFLUENCE OF MAGNESIUM-ASPARTATE-HYDROCHLORIDE TREATMENT UPON HORMONAL AND ENZYMATIC CHANGES AS WELL AS ALTERATIONSIN MEAT QUALITY DUE TO SLAUGHTERING STRESS IN PIGS

It is generally known that stress (especially slaughtering stress) aff ects the quality of pork meat. Since Mg pretreatment is known to incre ase stress compatibility and at the same time use of anti-stress drugs is forbidden or at least questionable, we tried to investigate whethe r Mg pretreatment would have an effect on the stress compatibility of pigs to be slaughtered and if so, how long and in which concentration Mg has to be administered to show a significant improvement in meat qu ality. To achieve this goal, we formed three groups, each consisting o f 15 pigs. The first group was fed with a normal diet (control group). The diet of the second group was enriched with a high concentration ( 40 mg/kg) of magnesium as aspartate hydrochloride (MAH) during the las t 5 days before slaughtering. The diet of the third group was enriched with a lower concentration of MAH (5 mg/kg), but given for 115 days. The administration of high concentrations of Mg in a short time (STHC, second group) did improve stress compatibility, but no influence upon meat quality. The third group (long term, low concentration LTLC of M AH) showed the lowest free epinephrine and norepinephrine plasma level s of all three groups. Moreover the lower plasma activitis of alpha HB DH, LDH and GLDH along with higher tissue MAO activities point to it l esser cell permeability in this group. If one takes cell stability as a parameter of meat quality, the low dosed administration of Mg for a long time (third group) shows the best results.