Effects of guanidinoacetic acid on the growth performance, meat quality, postmortem energy metabolism and muscle fibre types of finishing pigs

ContextMeat quality is increasingly being paid more attention by customers and enterprises. However, the modern pursuit of pork production has led to a decline in pork quality. Muscle fibre type is one of the important factors affecting meat quality that can be used as a key control point.AimsThis study set out to assess the effects of dietary guanidinoacetic acid (GAA) on the growth performance, meat quality, postmortem energy metabolism, and muscle fibre types of finishing pigs.MethodsIn total, 180 healthy Duroc x Landrace x Meishan cross castrated male pigs with the similar weight (average 90 kg) were randomly divided into three treatments, with five replicates (pens) per treatment and 12 pigs per pen, including a GAA-free basal diet and basal diet with 0.05% or 0.10% GAA for 15 days.Key resultsIn longissimus thoracis muscle, the results indicated that GAA supplementation decreased the drip loss and the cooking loss in 0.10% GAA group. Meanwhile, in semitendinosus muscle, 0.10% GAA addition increased pH45 min, and decreased the cooking loss. Additionally, GAA addition increased the content of ATP and AMP in semitendinosus muscle. The mRNA expressions of MyHC-I and MyHC-IIa were increased, whereas MyHC-IIx and MyHC-IIb were decreased. Moreover, in longissimus thoracis muscle, GAA addition promoted the mRNA expressions of CaM and NFATc1; in semitendinosus muscle, dietary GAA up-regulated the CnA and NFATc1 mRNA expressions.ConclusionsGAA addition improved the meat quality, enhanced postmortem energy metabolism and promoted the conversion of fast-muscle fibre to slow-muscle fibre via activating the CaN/NFAT signalling.ImplicationsThe addition of GAA can improve the meat quality of post-slaughter finishing pigs and provide a theoretical basis for the application of GAA in livestock production. Meat quality has recently been paid more attention by customers and enterprises. Although the improvement of pig breeding and management has increased pork yield, this has led to a decline of pork quality. We demonstrated that dietary supplementation with GAA significantly increases the postmortem muscle energy reserves and has beneficial effects on meat quality by achieving the transformation of muscle fibre types of finishing pigs. Our finding has important practical significance in discovering effective means to improve the meat quality.