| The purpose of this experiment was to study the effects of different ages of castration on Yanbian yellow beef quality and intramuscular fat deposition,and the related regulation of meat quality traits.Due to the long feeding cycle of Yanbian cattle,which is used to produce high-grade beef,if the growth is too slow and will affect its growth and development,and the cutting is too late to achieve the cutting effect,this experiment selects 50 healthy Yanbian cattle aged 6 months with similar blood.Randomly divided into 5 groups of 10 cows each.When the rearing conditions and nutritional levels were the same,the cuts were cut at 6,8,10,and 12 months respectively.The uncut group was not treated by cutting.The test groups were recorded as YG6,YG8,YG10,and YG12,every two months.Ultrasonic detection of subcutaneous fat thickness,lumbar muscle thickness,eye muscle area of the indicators to explore the law of change.Analysis of key enzymes and regulators of intramuscular fat anabolism in Yanbian yellow cattle by fattening up to 30 months of age:peroxisome proliferators-activated receptor-gamma(PPAR),stearoyl-coenzyme A desaturase(SCD),and muscle growth-related genes:Myogenic differentiation antigen(MYOD)and muscle regulation factor(MRF4)expression levels,analysis of intramuscular fat changes in different ages of castration and its regulation of gene expression and control of muscle growth-related gene expression.Samples were taken after slaughter and the effects of different ages of castration on Yanbian yellow beef quality were analyzed.The results of this study are as follows:(1)The subcutaneous fat content of the experimental group was higher than that of the uncastrated group,and the subcutaneous fat content of the YG6 group was the highest,and subcutaneous fat was found to grow slowly before 18 months of age,and after 18 months of age,the growth rate was accelerated and the psoas thickness was 16 Pre-monthly growth was slow,and the growth rate increased after 16 months of age.The area of unscruffed group and YG6,YG8,and YG10 groups grew slowly from 6 to 22 months of age,but accelerated after 22 months of age,and the YG12 group was in the whole Steadily growing within the growth cycle.(2)MYOD gene expression in the longissimus muscle area was the lowest in the YG6 group,and was significantly higher in the non-castrate group than in the experimental group(P<0.05).The expression of MRF4 gene in the longissimus dorsi muscle was significantly higher in the non-castration group than in the test group(P<0.05),and was significantly lower in the YG6 and 8 groups than in the YG10 and 12 groups(P<0.05).The YG6 group had the lowest expression.The expression of SCD gene in longissimus dorsi muscle was significantly higher in YG6 group than in other groups(P<0.05).The PPAR y expression in the longissimus muscle area was significantly lower in the uncut group than in the test group(P<0.05),and was significantly higher in the YG6 group than in the YG8,10,and 12 groups(P<0.05).The expression of MYOD gene in the scapular region was significantly higher in the non-castration group than in the experimental group(P<0.05).The expression level of YG6 group was significantly lower than that of YG8,lOand 12 groups(P<0.05).The expression level of MRF4 gene in the scapular site was significantly higher in the uncastrated group than in the experimental group(P<0.05),and the expression levels in the YG6 and 8 groups were significantly lower than those in the YG10 and 12 groups(P<0.05).The YG6 group had the lowest expression in the experimental group.The scapular site SCD gene YG6 group was significantly lower than other groups(P<0.05).There was no significant difference in PPAR? in the scapular region between YG10 and 12 groups.There was a significant difference in other groups.The YG6 group had the highest expression level.The expression of MYOD gene in the posterior buttocks was significantly higher in the non-castration group than in the test group(P<0.05),and significantly lower in the YG6 group than in the test group(P<0.05).The expression of MRF4 gene in posterior buttocks was significantly higher in the non-castration group than in the experimental group(P<0.05),YG6 and YG8 were significantly lower than those in YG610 and YG12(P<0.05)and the YG6 group had the lowest expression.The expression of SCD gene test group and YG12 group in posterior buttocks was significantly lower than that in other three groups(P<0.05).The YG6 group was significantly higher than other groups(P<0.05),and YG8 was significantly higher than YG10 group(P<0.05).The expression of PPAR y gene in YG6 group was significantly higher in posterior buttocks than in other groups(P<0.05).YG8 and YG10 were significantly higher than those in non-castration group(P<0.05).YG8 group was significantly higher than YG10 group.The difference between YG12 group and non-castration group was not significant.Significant.(3)The diameter of muscle fibers in the eye muscles and scapular region of the experimental group was significantly lower than that in the non-castration group(P<0.05).The area of muscle fibers in the scapular region was significantly lower than that in the non-castration group(P<0.05).The muscle fiber area in the ocular muscle region was YG6.The YG8 and YG12 groups were significantly smaller than those in the non-castrate group(P<0.05).The YG6,YG8,and YG12 muscle fiber density of the ophthalmic muscle region was significantly lower than that of the non-castration YG10 group(P<0.05).The scapular region was tested in diameter,area,and density of muscle fibers.The group was significantly smaller than the non-castrate group(P<0.05),and the YG6 group was the smallest.(4)The fat content in the eyes of YG6 and YG8 groups was significantly higher than that in other groups(P<0.05).The YG6 group had the highest fat content and the uncastrated group had the lowest fat content.The content of fat in the West Cold region in the YG6 group was significantly higher than that in the non-castrate group,YG10,and YG12 groups(P<0.05),while the YG8 group was significantly higher than the non-castrate group(P<0.05).The YG6 and YG8 groups in the upper brain area were significantly higher than those in the non-castrate group and the YG10 group(P<0.05).The fat content in bovine burdock was significantly higher in the YG6 group than in the non-castrate group,YG10,and YG12 groups(P<0.05).The content of YG6 in the posterior buttocks was significantly higher than that in the other groups(P<0.05)and was significantly lower in the non-castrate group than in the test group.The fat content of calves in YG8 and YG10 groups was significantly higher than that in other groups(P<0.05).The fat content in the loin area of YG6 group was significantly higher than that of non-castrated group,YG10,YG12 group(P<0.05),while YG8 and YG10 were significantly higher than those of non-castrate group and YG12 group(P<0.05).(5)The water content of the eye muscles in the non-castration group and YG6 was significantly higher than that in YG10(P<0.05).The moisture content of YG6 in the West cold was significantly lower than that in other groups(P<0.05).The water content of the upper brain regions YG6 and YG8 was significantly lower than that of the other groups(P<0.05),and was highest in the non-castration group.There was no significant difference in the moisture content of bovine burdock and post-hip.The water content in the loin area of YG6 group was significantly higher than that in each group(P<0.05).(6)There was no significant difference between the YG10 group and the uncut group(P>0.05).The YG6,YG8,and YG12 groups were significantly lower than the non-castrate group and the YG10 group(P<0.05).The YG6 and YG8 groups were significantly lower than the YG12 group(P<0.05).However,the YG6 group had the lowest long-term muscle shear force.The shear force in the uncooled part of the XiCheng group was significantly higher than that in the uncut group(P<0.05),and the YG6,YG8,and YG10 were significantly lower than the YG12(P<0.05).The non-castrate group in the upper brain region was significantly higher than the experimental group(P<0.05).The YG6 group was significantly lower than the experimental groups(P<0.05)and the YG8 and YG10 groups were significantly lower than the YG12 group(P<0.05).The shearing force of bovine burdock and hind-hip was significantly higher than that of the test group(P<0.05).The shear stress in the burdock was not significantly higher in the uncut group than in the test group(P<0.05),and was significantly lower in the YG6 and YG8 groups than in the YG10 and YG12 groups(P<0.05).The shearing force in the loin area and the YG112 group were significantly higher than those in the other groups(P<0.05),and YG6 and YG8 were significantly lower than those in the YG10 group(P<0.05).The results of this experiment show that the bulls that have been castrated can significantly promote the fat deposition of the cattle body during the fattening process,and the tenderness is significantly improved,and different cutting times will also affect the quality of the beef.The study found that 6-month-old castrated beef was the best quality. |
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