| Yeast preparation is a new type of feed additive produced by Saccharomyces cerevisiae.It can be divided into active dry yeast and yeast culture.According to previous reports,active dry yeast can have a positive impact on ruminant production,but no consistent effect has been achieved.At present,it is considered that the strain may be one of the factors affecting its application effect.This study consists of two parts.In the first part,the effects of different strains on rumen fermentation were compared to study whether the effects of different strains on the same substrate were different.In addition,active dry yeast also plays a positive role in improving muscle tenderness.Some studies have found that the improvement of tenderness by active dry yeast may be related to the improvement of antioxidant capacity.Therefore,in the second part of this study,Fubon active dry yeast was selected as an additive to study the effect of Fubon active dry yeast on growth performance,slaughter performance,meat quality and antioxidant capacity of fattening cattle.The effect of force provides theoretical data for revealing the mechanism of muscle tenderness.Experiment 1:Comparison of rumen fermentation effects of different active dry yeast preparations from different sources on high concentrate diet in vitro:This study was conducted to compare the effect of active dry yeast(Fubon yeast and Raman yeast)on gas production and parameters,methane production and rumen fermentation parameters byin vitro gas production technique based on total price mixed diet(TMR,concentrate roughage ratio 70:30),and the values of OMD,ME and yield of MCP were also predicted according to 24 h gas production.The results showed that,the gas production of each group increased,but there was no significant difference among the groups(P>0.05);The gas production delay time of T1 and T2 groups were shorter than that of the control group,but the difference was not significant(P>0.05);The pH,concentration of NH3-N and microbial protein value of each group were similar(P>0.05);The methane concentration of each experimental group was lower than that of the control group,but there was no significant difference(P>0.05);Compared with the control group,the lactic acid content of T1 and T2 groups were significantly decreased(P<0.05);compared with the control group,the content of volatile fatty acids and total volatile fatty acids in T1 and T2 groups had no significant difference(P>0.05);compared with the control group,the organic matter digestibility and metabolic energy value of each group had no significant difference(P>0.05).Conclusion:under the existing experimental conditions,Fubon and Raman active dry yeast preparations have a certain positive effect on the rumen fermentation of high concentrate feed,and can significantly reduce the rumen lactic acid content,and there is no significant difference between the two on the rumen fermentation of high-concentrate in vitro.Experiment 2:Effects of active dry yeast preparation on growth performance,slaughter performance meat quality,antioxidant capacity of fattening cattle:Forty six crossbred beef cattle(Simmental × Yanbian yellow cattle,18 months old,weighing 436 ± 35kg)were randomly divided into experimental group and control group for 145 days.The control group was fed with basal diet,and the experimental group was fed with Fubon active dry yeast preparation(ADY)according to the amount added by the manufacturer.During the experiment,the indexes related to growth performance were recorded.At the end of the experiment,carcass traits and meat quality were measured.Blood and muscle samples were collected.After blood was centrifuged,serum antioxidant indexes were determined.Muscle samples were directly used for the determination of antioxidant indexes.The results show that:(1)Growth performance:compared with the control group,ADY had no significant effect on the final weight,average daily gain,average daily feed intake and feed to weight ratio(P>0.05).(2)Slaughter performance:compared with the control group,ADY had no significant effect on carcass weight,slaughter rate,eye muscle area and high-grade meat weight(P>0.05),but the addition of ADY significantly improved the marbling deposition of beef(P<0.05).(3)Beef quality:ADY significantly increased intramuscular fat content(P<0.05),while other conventional indexes such as pH value,cooking loss,drip loss and meat color had no significant changes(P>0.05).Among the chemical composition indexes of muscle,ADY significantly increased intramuscular fat content(P<0.05),but had no significant effect on moisture,protein and ash(P>0.05).Compared with the control group,the contents of myristic acid,palmitic acid,palmitoleic acid,stearic acid,oleic acid and linoleic acid in muscle of experimental group had no significant difference(P>0.05).(4)Serum antioxidant index:compared with the control group,ADY significantly reduced the content of ROS in serum(P<0.05),but had no significant effect on GSH-PX,SOD,CAT,GR,MDA and total antioxidant capacity(P>0.05).(5)Muscle antioxidant index:compared with the control group,ADY significantly decreased the content of ROS in muscle(P<0.05),significantly increased the content of SOD(P<0.05),but had no significant effect on GSH-PX,SOD,CAT,GR,MDA and total antioxidant capacity(P>0.05).The results showed that the effect of ADY on beef tenderness and intramuscular fat content may be related to the improvement of antioxidant capacity.Therefore,it is necessary to study the relationship between antioxidant capacity and beef quality. |
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