Effect Of Oregano Essential Oil On The Production Performance And Muscle Antioxidant Performance Of Castrated Holstein Bulls

This experiment was conducted to study the effects of oregano essential oil(OEO)on production performance and antioxidant property of Holstein castrated bulls.In the experiment,18 castrated Holstein bulls(350.30±6.49)kg,aged about 10 months,in good health and similar physical condition,with no significant difference in weight,were randomly divided into two groups.The control group(CON group)was fed a basic diet,while the experimental group(OEO group)was supplemented with 20 g/(head·d)of OEO in the basic diet.The pretest period is 30 days,and the positive test period is 270 days,A total of 9 months(I-IX).Weighting is performed every 30 days,After the end of the experiment,blood was collected intravenously for 270 days to determine blood physiological and antioxidant indicators.After slaughter,slaughtering performance,meat quality,and muscle antioxidant performance were measured.1.Effects of adding OEO to the diet on production performance and economic benefits of castrated Holstein bullsThe final body weight(FBW)and average daily gain(ADG)of the OEO group were significantly increased by 10.09%and 18.95%compared to the CON group,respectively(P<0.05),and the feed weight ratio was significantly decreased by 19.11%(P<0.05).The live weight,head weight,hoof weight,meat weight,slaughter rate,net meat rate,carcass weight,and subcutaneous fat coverage of the OEO group were significantly higher than those of the CON group(P<0.05).The total weight of high-quality meat and high-grade meat in the OEO group were significantly higher than those in the CON group(P<0.05),which were 16.81%and 17.41%higher than those in the CON group,respectively.The revenue per cow of the OEO group increased by 867.73yuan compared to the CON group,and the profit increased by 30.80%.2.Effect of dietary OEO supplementation on postmortem meat quality and antioxidant capacity of castrated Holstein bullsOEO had significant effects on muscle brightness(L~*)(P<0.05),and significant effects on muscle water loss,cooking loss,dripping loss,marbling and shear force(P<0.01).The effect of maturity time on muscle marbling was significant(P<0.05),and the effect on other muscle indexes was very significant(P<0.01).The interaction between OEO and maturation time had significant effects on muscle redness(a~*),yellowness(b~*),water loss rate and drip loss(P<0.05),and the effects on muscle cooking loss and shear force were significant(P<0.01).Compared with the CON group,the OEO group significantly reduced muscle water content and increased crude fat content(P<0.05).The effects of OEO on muscle SOD content and T-AOC were significant(P<0.05),and the effects on muscle MDA and CAT content were significant(P<0.01).The effect of maturation time on muscle MDA,SOD,GSH-PX,CAT and ROS content was significant(P<0.01).The interaction between OEO and maturation time had a significant effect on the difference in muscle MDA content(P<0.05).3.Effect of adding OEO to the diet on blood physiological indicators and antioxidant performance of ovariectomized Holstein bulls at various stagesThere was no significant difference in blood physiological indicators between the OEO group and the CON group at stages I and V(P>0.05),At stage IX,the number of red blood cells(RBC),hemoglobin(HGB),and hematocrit(HCT)in OEO group were significantly higher than those in CON group(P<0.05).Compared with the CON group,the content of malondialdehyde(MDA)in the OEO group was significantly reduced by 9.78%,and the total antioxidant capacity(T-AOC)was significantly increased by 12.87%(P<0.05).In summary,adding OEO to the diet can improve the fattening performance of castrated Holstein bulls.Increase the proportion and economic benefits of high-quality and high-end meat.Improve the body’s metabolic capacity and alleviate the degree of oxidative damage to the body during growth and development.Helps improve the health level of castrated Holstein bulls in fattening.At the same time,adding OEO can improve the hydration and tenderness of postmortem beef from castrated Holstein bulls,which is beneficial for extending the shelf life of beef.