Muscle fiber type and metabolic profiles of four muscles from the African black ostrich

Muscle fiber type, fiber cross-sectional area (CSA), enzyme activities (citrate synthase (CS), 3-hydroxyacetyl Co A dehydrogenase (3HAD), lactate dehydrogenase (LDH) and phosphofructokinase (PFK)) and glycogen content were analyzed in the M. iliotibialis cranialis (ITC), M. iliotibialis lateralis, M. gastrocnemius (G) and M. fibularis longus (FL) muscles from 24 ostriches. Type I and II fiber proportions were similar across the 4 muscles, but the ITC had overall the smallest fibers. CS activity was the highest in the ITC, but similar between the remainder of the muscles. 3HAD activities were very low in all muscles, ranging between 1.9 and 2.7 mu mol/min/g protein, indicating poor beta-oxidation. The ITC also had the lowest PFK activity. Glycogen content averaged similar to 85 mmol/kg dry weight across the muscles with large intramuscular variations. The 4 ostrich muscles present with low fat oxidation capacity and low glycogen content, which could have significant implications on meat quality attributes.

Automated summary

This study analyzed muscle fiber type, fiber cross-sectional area, enzyme activities, and glycogen content in four muscles of 24 ostriches. The results showed similar proportions of type I and II fibers in all muscles, with the smallest fibers in the iliotibialis cranialis muscle. Citrate synthase activity was highest in the iliotibialis cranialis muscle and similar in the other muscles. 3-hydroxyacetyl Co A dehydrogenase activities were low in all muscles, indicating poor beta-oxidation. The iliotibialis cranialis muscle also had the lowest phosphofructokinase activity. Glycogen content varied within each muscle. These findings suggest that the ostrich muscles have low fat oxidation capacity and glycogen content, which could affect meat quality attributes.