Evaluation Of The Nutritional Value Of Different Sources Of Protein Feeds And Their Effect On The Growth Performance Of Luxi Cattle

In this study,the nutrient composition and rumen degradation characteristics of 10 unconventional protein feed materials（soybean meal,cotton seed meal,palm meal,brewer’s grains,soybean dregs,monosodium glutamate residue,distillers dried grains with solubles DDGS,peony seed meal,sesame meal and sunflower meal）were compared and analysed through 3 experiments.And three raw materials of cottonseed meal,monosodium glutamate residue and corn alcohol residue were selected,The feed formula was prepared to according to the nutritional needs of beef cattle.The feed formulations were then fed to beef cattle to investigate their effects on the growth performance of Luxi cattle.Experiment 1: comparative study on nutritional components of protein feeds from different sources.The nutrient composition and amino acid composition of 10 protein feeds were determined,and the nutrient composition was analysed using the Cornell Net Carbohydrate and Protein Syste（CNCPS）and total digestible nutrients（TDN）were calculated.The results showed that:1.the crude protein（CP）content of soybean meal was significantly lower than that of monosodium glutamate residue（P < 0.05）,but not significantly different from that of cottonseed meal（P > 0.05）.There was a significant difference in the content of neutral detergent fiber（NDF）among the 10 raw materials（P <0.05）.The content of NDF in palm meal was the highest and that in monosodium glutamate residue was the lowest.The contents of neutral detergent fiber（NDF）,acid detergent fiber（ADF）and lignin（ADL）in monosodium glutamate residue were significantly lower than those in other raw materials（P < 0.05）.2.The contents of total carbohydrate（CHO）in soybean meal and cottonseed meal were between 39% ～ 40%,and there was no significant difference between them（P > 0.05）;The CHO content of monosodium glutamate residue is the lowest and that of soybean residue is the highest.Soybean meal is 32.26% higher and33.9% lower than that of monosodium glutamate residue.The content of rapid degradation part（PB1）of monosodium glutamate residue was the highest,85.83%,which was significantly higher than that of other raw materials（P < 0.05）;There was no significant difference in PB1 content between soybean meal and DDGS（P > 0.05）,and there was no significant difference in PB1 content between soybean meal and cottonseed meal（P > 0.05）.3.The content of essential amino acids in soybean meal（23.16%）was the highest,followed by monosodium glutamate residue（21.82%）,and cottonseed meal（21.77%）was the third.There was no significant difference in the content of essential amino acids（EAA）between monosodium glutamate residue and cottonseed meal（P > 0.05）.There were differences in the contents of 18 amino acids between soybean meal and monosodium glutamate residue,but each amino acid component of the two raw materials was at a relatively close level.4.There was no significant difference between the TDN contents of DDGS and monosodium glutamate residue（P > 0.05）,but they were significantly higher than those of the other eight ingredients（P < 0.05）;there was no significant difference between the TDN contents of soya bean meal and soya bean residue（P > 0.05）.Experiment 2: rumen degradation rates of different sources of protein feeds were determined by the nylon bag method.Luxi Cattle and Limousin crossbred beef cattle with permanent rumen fistula were selected.The contents of DM,CP,NDF and ADF of the residual residue in the nylon bag were measured at 7 time points of 2,4,8,12,24,36 and 48 h,and the rumen degradation rate was calculated.The results showed that:1.In terms of DM degradation rate,the rapid degradation fraction content of DDGS was the highest among the10 raw materials reaching 28.39%,followed by soybean meal 25.03% and peony seed meal23.26%,There was no significant difference between soybean meal and DDGS and peony seed meal（P > 0.05）;However,the content of rapidly degraded part of the three raw materials was significantly higher than that of other raw materials（P < 0.05）.The effective degradation rate of soybean meal was 65.14%,which was lower than that of monosodium glutamate residue,and there was significant difference between them（P < 0.05）.2.In terms of CP degradation rate,the content of rapid degradation part of soybean residue and DDGS reached more than 30%,which was significantly higher than that of other 8 raw materials（P < 0.05）.There was significant difference in the content of slow degradation part of 10 kinds of raw materials（P < 0.05）.From the potential degradation part,the potential degradation part of crude protein of soybean meal,cottonseed meal,palm meal,soybean residue,DDGS and sunflower meal reached more than 90%.The highest effective degradation rate of cottonseed meal was 78.82%;Secondly,the peony seed meal was 64.44%;Soybean meal was in the third place,and the effective degradation rate was 59.43%.3.The results of NDF degradation rate showed that there was no significant difference in the content of slow degradation part between soybean meal and cottonseed meal（P > 0.05）,both of which were significantly lower than soybean residue（P < 0.05）,but significantly higher than palm meal,brewer’s grains,monosodium glutamate residue,DDGS,peony seed meal,sesame seed meal and sunflower meal.4.In terms of ADF degradation rate,the contents of fast degradation parts of soybean residue and DDGS were 2.62% and 2.57% respectively,which were significantly lower than other raw materials（P < 0.05）.The content of slow degradation part of monosodium glutamate residue was the lowest,0.82%,which was significantly lower than that of other 9 raw materials（P < 0.05）;The content of slow degradation part of soybean meal and sesame meal was about 60%,and there was no significant difference between them（P >0.05）.There were significant differences in the effective degradation rates of ADF among 10 raw materials（P < 0.05）.5.According to the comprehensive nutritional value,the order from high to low is monosodium glutamate residue,soybean meal,cottonseed meal,DDGS,peony seed meal,sesame meal,distiller’s grains,soybean residue,sunflower meal and palm meal.Experiment 3: effect of different sources of protein feeds and their addition ratios on the growth performance of Luxi cattle.Using the membership function to rank the comprehensive nutritional value of the results of Experiment 1 and Experiment 2,monosodium glutamate residue,cottonseed meal and DDGS were selected to replace soybean meal.According to the nutritional needs of beef cattle,monosodium glutamate residue,cottonseed meal and DDGS were used in combination to prepare two feed formulas that replace soybean meal in feed.Thirty-six Luxi cattle with good body condition and similar body weight（250 ± 20）kg were selected and randomly divided into 3 groups with 12 cattle in each group,and the feeding period was 60 days.The control group was fed traditional soybean meal diet,the treatment group I used 2% cottonseed meal + 1.8% DDGS + 1.2% monosodium glutamate residue to replace 5% soybean meal in the diet,and the treatment group II used 5% cottonseed meal +6.5% DDGS + 1.5% monosodium glutamate residue Substitute 10% soybean meal in the diet.The effects of different sources of protein and their addition ratios on the growth performance,apparent nutrient digestibility and blood index of Luxi cattle were studied.The results showed that:1.The addition of cottonseed meal,monosodium glutamate residue and DDGS had no significant effect on the daily weight gain and dry matter intake of Luxi cattle（P > 0.05）;2.The apparent digestibility of DM in the control group was significantly higher than that of the two treatment groups（P < 0.05）;There was no significant difference in apparent digestibility of NDF among the three groups（P > 0.05）;There was significant difference in ADF digestibility among the three groups（P < 0.05）.The apparent digestibility of CP in treatment group Ⅱ was significantly higher than that in control group（P < 0.05）;The apparent digestibility of EE in the control group（82.96%）was the highest,12.77% higher than that in the treatment group Ⅱ.The apparent digestibility of EE in the control group was significantly higher than that in the two treatment groups（P < 0.05）.3.The content of alanine aminotransferase（ALT）in the control group was significantly higher than that in the two treatment groups（P < 0.001）,and there was no significant difference between the two treatment groups（P > 0.05）.The content of aspartate aminotransferase（AST）in treatment group II was the highest,followed by control group and lowest in treatment group I.Treatment group I was significantly lower than control group and treatment group II（P <0.05）.The differences in blood glucose（GLU）content among the three groups were extremely significant（P < 0.001）,the highest in treatment group I was 9.70 mmol/L,and the lowest in control group was 6.45 mmol/L.There was no significant difference in blood immune indexes and hormone indexes among the three groups（P > 0.05）.4.The feed-to-meat ratio of treatment group I was significantly lower than that of control group and treatment group II（P < 0.05）,and the average weight gain per kilogram of treatment group I was significantly lower than that of control group and treatment group II（P < 0.05）.To sum up,when 2% cottonseed meal + 1.8% DDGS + 1.2% monosodium glutamate residues are used in the concentrate to replace 5% soybean meal in the diet,the breeding cost can be reduced and the breeding efficiency can be improved.