| The research choose the main beef breed, Red Angus cattle, Simmental cattle, Grassland Red cattle and Charolais cattle in high generation hybrid in Inner Mongolia to compare the price of feed, growth performance, carcass strait, regular nutrition indices, flavor compounds, muscle fiber structure, biochemical parameters of fat metabolism and mRNA expression level related to hormone level and fat metabolism in the same feeding condition. The finding will provide scientific basis for selection of appropriate beef breed and improvement of beef breed in this area. Experiment was divided into four parts:Part one:Comparative study of meat quality in different beef cattle breeds under the same feeding conditionsIn the same fattening condition, longest back muscle between12to13left ribs was chosen as test samples in Red Angus cattle, Simmental cattle, Grassland Red cattle and Charolais cattle after slaughter. The laboratory analysis methods were as follows: Routine analysis method, Paraffin technology, electron microscopy technology and Meteorological chromatographic analysis technique. The results were as follows:(1) Grassland Red cattle meat protein and fat content were higher than other varieties(P<0.05); Red Angus cattle meat moisture content was higher than other varieties(P<0.05)and ash content of beef cattle muscle in4varieties is no significant difference(P>0.05); Phosphorus contents in four breeds were:Red Angus cattle>Grassland Red cattle>Charolais cattle> Simmental cattle, Red Angus cattle Phosphorus contents were higher than other varieties(P<0.05); The calcium content comparison in four breeds was:Grassland Red cattle> Simmental cattle> Charolais cattle> Red Angus cattle, Simmental cattle and Grassland Red cattle had no significant difference(P>0.05), Charolais cattle and Red Angus cattle had no significant difference(P>0.05).(2) Grassland Red cattle in Slaughter rate, eye muscle area and Back fat thickness were higher than other varieties(P<0.05); Red Angus cattle were lower than other varieties in Shear force, water loss rate and drop of water loss(P<0.05), however, was higher than other varieties in Cooked rate(P<0.05); Simmental cattle had higher in PH value than other varieties(P<0.05).(3) Red Angus cattle were higher in Muscle fiber diameter and Muscle fiber area than other varieties(P<0.05)and lower in Muscle fiber density and Sarcomere length(P<0.05).(4) Red Angus cattle Fatty acids content in PUFA/SFA and n-6/n-3were higher than other varieties(P<0.05); Grassland Red cattle in MUFA/SFA was higher than other varieties (P>0.05); Grassland Red cattle muscle amino acid content was higher in the essential amino acid content, Non-essential amino acid content, content of tasty amino acids, lysine content and glutamic acid than other varieties(P<0.05).Part two:Comparative study of blood biochemical index and hormone concentration in different beef cattle breeds under the same feeding conditionsCollection of blood from oxtail vein picks was carried out before slaughter and numbered, centrifugated, and fresh serum was obtained. The laboratory analysis method was as followed:GPO-PAP, glucose oxidase and radioimmunoassay, assay blood biochemical index and hormone concentration. The results were as follows:(1) Grassland Red cattle serum glucose concentration, triglyceride levels and cholesterol concentration were higher than other varieties (P<0.05); Red Angus cattle High density lipoprotein cholesterol concentration was higher than other varieties(P<0.05); Serum low density lipoprotein content comparison in four breeds was:Grassland Red cattle>Charolais cattle>Simmental cattle>Red Angus cattle, Grassland Red cattle and Charolais cattle had significant difference(P<0.05), Simmental cattle and Red Angus cattle had no significant difference(P>0.05).(2) Grassland Red cattle serum insulin and Insulin-like growth factor-Ⅰ concentration were higher than other varieties(P<0.05);Red Angus cattle cortiso1,3,5,3-Triiodothyronine, growth hormone, leptin, pancreas glucagon and tumor necrosis factor-a concentration was higher than other varieties(P><0.05).Part three Comparative study of mRNA expression of fatty metabolism related factors in different beef cattle breeds under the same feeding conditionsWe took longissimus dorsi from12-13costa of left carcass as samples after slaughtering and spliting into two part. We examined mRNA expression of lipometabolism relevant gene of longissimus dorsi of beef cattles from4species through FQ-PCR.Our experiment indicated that the mRNA expression of PPAR-y and LPL of Grassland Red cattle were significantly higher than others(P<0.05).Part four:Comparative research of production performance in different beef cattle breeds under the same feeding conditionsThe Simmenta cattle, Angus cattle, Charolais cattle and Grassland Red cattle were used in this study.They were fattening180d in the same condition. It used subtraction to assay feed efficiency. Beef cattle were excited acid before slaughter, and then determined performance of meat production by weighting method. The result showed that, firstly, the daily gain of Grassland Red cattle was significantly greater than that of other3 species(P<0.05), his consumption of concentrated feed and the cost of feed was significantly lower than others(P<0.05).Second, the weight of high-grade beef and quality beef of Grassland Red was significantly higher than others(P<0.05); although performance of the high-grade beef production was nonsignificant difference between4species,(P＞0.05), there was a successively decreasing tendency on that of Grassland Red, Simmental cattle, Charolais cattle, Angus cattle; and there was a successively decreasing tendency on the weight of hind leg of Simmental cattle, Grassland Red cattle, Charolais cattle, Angus. It was nonsignificant difference between Charolais cattle and Angus cattle (P>0.05),but it was significant difference between Charolais cattle and other species(P<0.05); although the performance of hind leg production was nonsignificant difference between them(P>0.05), there was a successively increasing tendency on that of Grassland Red cattle, Angus cattle, Simmental cattle, Charolais cattle. The production of quality beef of Simmental cattle was significantly higher than others(P<0.05).In conclusion, Grassland Red cattle wasdominant on the nutritional value of beef, feed efficiency, production of high-grade beef and lipdosis. Grassland Red cattle was fit for fattening to breed special strain of beef cattle in this area. |
PDF Full Text Request