Effects of diet protein level on different muscle fiber hypertrophy in finishing pigs (II).

The experiment comparatively studied the effect of diet protein level on different muscle fiber hypertrophy in finishing pigs.According to a completely randomized block design,54 growing pigs(Larger×Landrace) with an average weight of 53kg were assigned to three treatments(with three replicates per treatment).The diets contained a same amino acid pattern(TDLys∶ TDMet∶TDThr∶TDTrp=100∶34.6∶71.7∶19.2) and a same digestibile energy level(DE 3200 kcal/kg) with different crude protein levels(CP 10%,18% and 26% respectively).The trial lasted for 67 days before slaughter and longissimus dorsi(LD),psoas major(PM),semaitendinosus(ST),semimembranosus(SM),arm triceps(AT),glutaeus medius(GM) muscle samples were taken to measure the great muscle bundle distance,muscle fiber distance and muscle bundle distance.There was a positive correlation between muscle fiber distance,muscle bundles distance and protein level(p0.01),a negative correlation between great muscle bundles and protein level(p0.01).The diet protein level and the different muscle all influenced muscle fiber hypertrophy in the finishing pigs,and there was an interaction between them(p0.01).With muscle thickening,there were increases in connective tissue and adipose tissue between muscle,leading to descend of muscle fiber density and distance between great muscle bundles.