Effects Of Dietary Guanidine Acetic Acid Supplementation On Growth Performance,Carcass Traits And Meat Quality In Finishing Pigs

This study aimed to evaluate the effects of dietary guanidine acetic acid(GAA)supplementation on growth performance,carcass traits and meat quality in finishing pigs.The results would provide a theoretical basis for the application of GAA in the productive practice.Experiment ?: Effect of GAA supplementation on growth performance,carcass traits in finishing pigs.This experiment aimed to evaluate the effects of GAA supplementation on growth performance,carcass traits in finishing pigs.A total of 160 crossbred pigs [Duroc×Landrace×Yorkshire] with an average body weight(BW)of approximately 80.00 ± 2.50 kg were randomly assigned to five groups with four replicates(eight pigs per replicates)and fed with a basal diet or a basal diet supplemented with 0.03%,0.06%,0.09% and 0.12% GAA,respectively.Our result showed that:1)ADG and ADFI showed a linearly and quadratic effect(P<0.001 and P=0.001,P=0.001 and P=0.006)as dietary GAA increased.F/G showed a quadratic effect(P=0.010)with the lowest value 0.06% of the GAA.2)Carcass traits showed a linearly increased as dietary GAA increased(P=0.044),Backfat thickness and Loin muscle area showed a quadratic effect(P=0.018,P=0.012)as dietary GAA increased.Lean meat showed a linearly or quadratic effect(P=0.013 and P=0.008)as dietary GAA increased.The percentage of lean meat was higher than the control group due to higher loin muscle area in the 0.06%GAA(P<0.05),as well as the backfat thickness was lower than the control group(P<0.05).In conclusion,GAA can enhance the growth performance and the percentage of lean meat,and decrease the backfat thickness.In addition,0.06%GAA is an optimum addition level in the finishing pigs.Experiment ?: Effect of GAA supplementation on Longissimus dorsi muscle fiber morphology,meat quality in finishing pigs.This experiment aimed to evaluate the effects of GAA supplementation on Longissimus dorsi muscle fiber morphology,meat quality in finishing pigs.Grouping and diets are as same as the experiment ?.The results as follows: 1)with the increasing levels of GAA,the drip loss presented a linearly or quadratic effect(P=0.013 and P=0.042),so did the intermuscular fat(P=0.002 and P=0.007).The shear force tended to have a quadratic effect(P=0.031).The highest value of shear force was in pigs fed 0.06% GAA(P<0.05).The drip loss was lower than control group,significantly(P<0.05).2)The cross-sectional area of muscle fiber and the muscle fiber density presented a quadratic effect(P=0.004 and P=0.009,respectively)with increasing GAA supplementation to the diet.And the highest value of cross-sectional area of muscle fiber was in pigs fed 0.06% GAA.By considering the Longissimus dorsi muscle fiber morphology and meat quality,0.06%GAA is an optimum addition level in the finishing pigs.Experiment ?: Effect of GAA supplementation on Serum biochemistry,the expression of muscle growth-related genes and fat metabolism genes in finishing pigsThis experiment aimed to evaluate the effects of GAA supplementation on Serum biochemistry,the expression of muscle growth-related genes and fat metabolism genes in finishing pigs.Grouping and diets are as same as the experiment ?.The results as follows: 1)with the increasing levels of GAA,there were a linearly or quadratically increase in the concentrations of serum GH(P=0.019,P=0.032)and UN(P=0.010,P=0.023).2)The mRNA levels of FAS tended to have a linearly or quadratic effect(P<0.001,P=0.001)as GAA supplementation increased.GAA tended to increase the gene expression of CPT-1 in a quadratic does-dependent manner(P=0.098)and the mRNA levels of CPT-1 in pigs fed 0.06% GAA was higher than other treatments(P<0.05).The mRNA abundance of Myod in pigs fed 0.06%GAA were higher than other treatments and the control group(P<0.05).GAA also increased the gene expression of Myostain and Myod in quadratic dosedependent manner(P=0.011 and P=0.008,respectively).The mRNA abundance of Myostain in pigs fed 0.06% GAA was lower than the control and other treatments(P<0.05).The mRNA levels of MyHC ?a and MyHC ?b showed a quadratic effect(P=0.010 and P=0.011,respectively)with increasing GAA supplementation to the diet.The mRNA expression of MyHC ?x and MyHC ?b was increased in pigs fed 0.06%GAA compared with the control and other treatments(P<0.05).By considering serum biochemistry and the expression of muscle growth-related genes and fat metabolism genes,0.06%GAA is an optimum addition level in the finishing pigs.