This study aimed to evaluate the effects of dietary guanidine acetic acid (GAA) supplementation on growth performance, carcass traits and the expression of muscle growth-related genes in finishing pigs. A total of 128 (81.03 ± 1.09 kg body weight) crossbred pigs (Duroc × Landrace ×Yorkshire) were blocked by body weight and allotted to 16 pens (eight pigs per pen), and pens were randomly assigned within blocks to one of five dietary treatments, with a basal diet (control group) or a basal diet supplemented with 0.03%, 0.06% and 0.09% GAA respectively. During the 60-day trial, GAA increased the average dairy gain (ADG) and average daily feed intake (ADFI) (p < .05). The back fat thickness of pigs fed 0.06% GAA was lower than other groups (p < .05). Pigs fed 0.06% GAA had improved lean meat percentage, loin muscle area, shear force and cross-sectional area of muscle fibre in comparison with control group (p < .05). The drop loss and the muscle fibre density in pigs fed 0.06% GAA were lower than control (p < .05). In addition, dietary GAA enhanced the expression of myosin heavy chain gene (MYH4), myogenic determination (Myod) and myogenic factor 5 (Myf5) in longissimus dorsi and carnitine palmitoyltransferase-1(CPT-1) in liver (p < .05). Meanwhile, GAA decreased the expression of Myostatin in longissimus dorsi and fatty acid synthase (FAS) in liver (p < .05). In conclusion, our results showed that appropriate dietary GAA supplementation (0.06%) promotes skeletal muscle development through changing myogenic gene expression and myofibre characteristics.
Keywords: finishing pigs; guanidine acetic acid; meat quality; performance; skeletal muscle development.
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