The Effect Of Processing Soybean Feed On The Molecular Structure Of Protein And Digestion Performance Of Beef Cattle

Soybean feed is the most common source of protein feed for beef cattle production.But studies show that the protein utilization rate of different processed soybean feed was different,because the different processing methods of soybean products have an important influence on the molecular structure of protein.The Total reflection Fourier transform infrared spectroscopy?ATR-FT/IR?was using in this study,to search the effects of different treatments on protein molecular structure and digestion performance of beef cattle by the protein primary structure?amide I and amide II?and secondary structure??-helix and ?-sheet?.In order to improve the utilization rate of beef cattle feed to improve the daily gain of beef cattle.This study is divided into 3 parts:Part 1: Using ATR-FT/IR to detect the molecular structure of soybean protein.The experiment was carried out to remove the impurities from the soybean seeds collected by the Xiangyang practice base of Northeast Agricultural University.Soybean was crushed and over 40 mesh?0.425mm?sieve.The samples were divided into 4 treatments with 3 replicates per treatment,control sample C was kept raw,dry roasted sample?T₁?was dry roasted at 120? for 1h;microwave irradiated sample?T₂?was heated by microwave at 900 w for 5 min and expanded sample?T3?.Using ATR-FT/IR to analyze the molecular structure of protein in 4 treatments.Results show:Primary structure:?1?The peak height of amide II: T₁,T₂ and T3?0.0575,0.0611 and 0.0406?were lower than C?0.0920?significantly?P=0.010?;?2?The peak area of amide I: T₁,T₂ and T3?4.8227? 4.7417 and 3.6480?were lower than C?6.7360?significantly?0.027?;The peak area of amide II: T₁,T₂ and T3?2.1170,2.1967 and 1.2173?were lower than C?3.284?significantly?P=0.008?,and T3 were lower than T₁ and T₂ Significantly?P<0.05?;?4?The ratios of amide I and amide II peak area:T3?2.9967?were higher than C?2.0512?significantly?P=0.027?;Secondary structure?4?The peak height of ?-sheet: T₁,T₂ and T3?0.0905,0.1008 and 0.0752?were lower than C?0.1483?significantly?P<0.010?.And They were 38.98%,32.03% and 49.29% lower than those in the control group respectively;?5?The ratios of ?-helix and ?-sheet: T₁?1.0692?were higher than C?0.7730?significantly?P<0.001?.Part 2: Effects of different soybean products on intestinal digestibility in ruminants.The improved three step method of in vitro: Sample processing and grouping were divided into 4 groups,C,T₁,T₂ and T3,3 replicates per group.The samples were first used to simulate ruminal digestion of 16 h in vitro to obtain rumen residue.Then the residual nitrogen content of 15 mg was measured by three step method.Determination of nitrogen content by three step method,and digestibility of intestinal protein = nitrogen content of degradation/residual nitrogen content in rumen.Results show that?1?Small intestinal protein digestibility: T₁?90.76%?,T₂?85.31%?and T3?93.25%?were higher than C?82.59%?significantly?P=0.006?.They were 9.89%?3.29%? 12.91% higher than those in the control group respectively;?2?Correlation between molecular structure of feed protein and digestibility of small intestine:There was a significant negative correlation between the peak height of amide II and the corresponding small intestinal digestion protein in each group?r=-0.623,P=0.030?;There was a significant negative correlation between the peak area of amide I and digestive protein in small intestine?r=-0.628,P=0.029?;?3?The peak height of ?-sheet was significantly negatively correlated with the digestive protein of small intestine?r=-0.738,P=0.006?;The ratios of ?-helix and ?-sheet was significantly positively correlated with small intestinal digestion protein?r=0.704,P=0.011?.Part3 Effect of feeding soybean feed with different treatments on weight gain of beef cattleExperiment chose 40 weight close?340.0kg ± 10.0kg?month age 16-18 months of healthy Simmental Steers.Single factor randomized block design,40 steers were randomly divided into 4 groups,each group had 10 replicates,each with a repeat of 1 steers.C fed soybean?due to the production of raw soybean is not allowed to feed directly,so the Fed cooked soybean as control?,T₁ fed dry roasted soybean at 120 ?,T₂ fed microwaved soybean,T3 fed expanded soybean.Feed 4kg per day,each group was fed with soybean feed 0.58 kg,For 30 d feeding.And the weight of beef cattle in each group was measured before and after the experiment.The results are as follows:The average daily gain of T3?1.21kg?was higher than C?1.03kg?,T₁?1.08kg?and T₂?1.04kg?significantly?P=0.030?,and increase 17.47%,12.04% and 16.35% than C T₁,T₂ and T3.So it come to conclusion that in this experiment,the maximum weight gain of beef cattle was the highest,The other three groups were not significantly different?P<0.05?.The above results are combined with production requirements and discussed and analyzed that?1?The peak of the ?-sheet of the 3 kinds of Soybean?dry roast,microwave and puffing?was significantly lower than that of the control group?38.98%,32.03% and 49.29%?;?2?The ruminants protein digestibility in the small intestine of 3 treatments?dry roasted,microwaved and expended?was significantly higher than that of raw soybean,and dry roasted Expended higher than microwaved soybeans;?3?The peak height of ?-sheet was significantly negatively correlated with the digestive protein of small intestine?r=-0.738,P=0.006?;The ratios of ?-helix and ?-sheet was significantly positively correlated with small intestinal digestion protein?r=0.704,P=0.011?.And it can be predicted that the digestibility of soybean and the small intestine of ruminants treated by different molecular structures.?4?The effect of beef cattle was better than other groups,while the average daily gain of 30 days?0.18kg?was higher than that of the control group17.47%.