| In this study,the effects of dietary guanidinoacetic acid on the growth performance,blood indicators,slaughter performance,and meat quality of Jinjiang cattle were studied through feeding experiments and slaughter tests.The research is mainly divided into three parts.In the first section of the experiment,the effect of guanidinoacetic acid added to the diet on the growth performance and nutrient digestibility of Jinjiang cattle was studied.The experiment selected 45 healthy Jinjiang yellow bulls around 24 months old with an average weight of(350.44±4.55)kg,randomly divided into 5 groups,and added 0%,0.05%,0.1%,0.2 respectively on the basis of the basic diet % And 0.4% GAA.7 days pre-feeding,45 days in the trial period.The results show that:(1)growth performance,compared with the control group,the addition of 0.2% and 0.4% GAA in the diet can significantly increase the average daily weight gain(P<0.05),in which the daily weight gain of the 0.2% GAA group is the highest value;GAA added group can significantly reduce the feed-to-meat ratio(P<0.01).Among them,0.2%GAA added group had the best effect.GAA had no significant effect on the feed intake of each group(P>0.05)(2)Apparent digestibility of nutrients.Compared with the control group,the apparent digestibility of nutrients in the GAA added group was not significantly different(P>0.05).To sum up,the addition of 0.2% and 0.4%guanidinoacetic acid in the diet significantly increased the daily weight gain and decreased the feed-to-meat ratio,but did not significantly affect the feed intake and the apparent digestibility of nutrients.Among them,the effect of adding 0.2% is the best.In the second section of the experiment,the effects of dietary supplementation of GAA on the blood biochemical,GAA metabolism related enzymes,and antioxidant indexes of Jinjiang cattle were studied.After the feeding test,blood was collected and related indexes were measured.The results show that:(1)Compared with the control group,the GAA supplementation group can significantly increase the levels of aspartate aminotransferase and glutamyl transpeptidase(P<0.05),and improve the dehydrogenation of alanine aminotransferase,creatine kinase,and hydroxybutyrate The trend of enzymes and lactate dehydrogenase(P>0.05).(2)Compared with the control group,the GAA added group can significantly reduce blood glucose(P<0.05),increase the content of creatinine and homocysteine(P<0.05),and have no significant effect on other serum biochemical indicators.(3)Compared with the control group,the GAA addition group significantly increased the level of oxidative dismutase(P<0.05),and there was no significant difference in malondialdehyde and total antioxidant value(P>0.05).In summary,the addition of GAA in the diet can be metabolized into the liver through the rumen,and its metabolism improves the activity of liver metabolism-related enzymes in serum: adding GAA has a certain hypoglycemic effect and increasing blood creatinine content: adding GAA can Improve the anti-oxidation capacity of Jinjiang cattle.The third section of the experiment studies the effect of dietary supplementation of GAA on the slaughter performance and meat quality of Jinjiang cattle.After the feeding experiment,the best dose group and the control group were selected for slaughter,and related indicators were determined.The results showed that:(1)Compared with the control group,the difference in backfat thickness and slaughter rate in the experimental group was not significant(P>0.05),but the carcass weight and eye muscle area in the GAA group increased significantly(P<0.05).(2)The GAA added group significantly reduced the brightness value of the modified Jinjiang yellow dorsal longest muscle(P<0.05),and significantly increased the redness value(P<0.05)and yellowness value of the longest back muscle(P<0.05),Significantly reduced the drip loss of semitendinosus muscle(P<0.05).However,the 0.2%GAA addition group had no significant effect on the longest dorsal muscle pH45 min,pH24 h,drip loss,cooking loss and shear force(P>0.05);pH45 min,pH24 h,flesh color of semitendinosus muscle(L*,a*,B*),cooking loss and shear force have no significant effect(P>0.05).In summary,the addition of GAA can improve the slaughter performance and carcass quality of Jinjiang cattle,and has a certain improvement effect on beef quality.Under this test condition,the appropriate dosage is 0.2%.In summary,under the conditions of this experiment,the addition of GAA can significantly improve the growth performance of Jinjiang cattle,reduce the feed-to-meat ratio,and have a certain effect on the conversion rate of feed.The addition of GAA to the diet can increase the antioxidant capacity of Jinjiang cattle,and it has a tendency to increase liver transaminase,dehydrogenase,etc.,verifying that GAA can act on the body through the ruminant digestive system and synthesize creatine in the liver.In this experiment,the addition of 0.2% GAA can significantly improve the slaughter performance and carcass quality of Jinjiang cattle,and play a certain role in improving the quality of beef.Comprehensive production performance and consideration of feed conversion rate,and final slaughter,verified that under this test condition,the appropriate amount of GAA is 0.2%. |
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