Conclusions: QG PCR is the most sensitive method for diagnostics of Y-sequences.

Glutamic acid content did not significantly differ among the four QGs in either loin or rump.

Our results confirmed that a major determinant of QG is the MS; thus, intramuscular fat content.

Fat content in loin was highest but protein and moisture contents were lowest in QG 1++.

Urine recovery (% administered dose) and the contribution of PG and QG to urinary elimination were calculated.