Effects Of Agricultural By-Products Feed On Growth Performance And Rumen Environment Of Beef Cattle And Mutton Sheep

In order to make full and reasonable use of agricultural and by-products instead of conventional feed in ruminant feed to reduce feed cost,and solve the palatability and non-standardization problems caused by the application of agricultural and by-products,this paper mainly studied the effects of agricultural and by-products instead of corn on the growth performance,nutrient digestion and rumen fermentation of beef cattle,and discussed the feasibility of agricultural and by-products to reduce the breeding cost.On this basis,the feasibility of total mixed ration granulation technology to solve the palatability and instability caused by the application of agricultural by-products was studied.To this end,we conducted the following four experiments.Trial 1:Effects of partial replacement of corn by agricultural by-products on growth performance,nutrient digestion and blood metabolism indexes of Holstein Bulls.Thirty healthy Holstein bulls with similar body weight（289.77kg±10.05kg）were randomly divided into 3 groups with 10 bulls in each group.Control group（group A）:50%corn+7.5%spouting corn husk+7.5%soybean husk+7.5%palm meal+7.5%cassava residue,test group 1（Group B）:40%corn+10%spouting corn husk+10%soybean husk+10%palm meal+10%cassava residue,test group 2（Group C）:30%corn+12.5%spouting corn husk+12.5%soybean husk+12.5%palm meal+12.5%cassava residue.Alfalfa hay was fed to all roughage groups.The results showed that the feed intake of concentrate and coarse dry matter intake was significantly decreased by agricultural by-products（P<0.01）,the ratio of feed to gain was significantly increased（P<0.05）,the daily gain（ADG）was gradually decreased but the difference was not significant（P>0.05）,and the daily gain income and gross profit were decreased.The digestibility of dry matter（DM）was significantly decreased（P<0.01）,but the digestibility of crude protein（CP）,neutral detergent fiber（NDF）and acid detergent fiber（ADF）were not significantly different among all groups（P>0.05）.Alanine aminotransferase（ALT）increased significantly（P<0.01）,aspartate aminotransferase/AST/ALT and low density lipoprotein（LDL）decreased significantly（P<0.01）,but there were no significant differences in other indexes（P>0.05）.Trial 2:Effects of partial corn concentrate replacement by agricultural by-products on rumen fermentation and rumen microflora in Holstein bulls.Experimental design and animal feeding management were the same as in experiment 1.Rumen fluid samples were collected before morning feeding on the last day of the official trial period,stored in liquid nitrogen and sent to the laboratory for detection of rumen fermentation indexes and rumen microflora.The results showed that replacing corn concentrate with agricultural by-products had no effect on rumen pH of beef cattle（P>0.05）.The concentration of ammonia nitrogen（NH3-N）in group B was significantly higher than that in groups A and C（P<0.05）.In terms of volatile fatty acid（VFA）indexes,The concentration of total volatile fatty acids（TVFA）in group B was significantly higher than that in groups A and C（P<0.01）.With the increase of substitution ratio,the concentrations of acetic acid（AA）and butyric acid（BA）were significantly increased（P<0.01）,and the acetic acid/propionic acid（A/P）showed an increasing trend（P>0.05）.The concentration of valerate acid（VA）was decreased（P<0.01）.There was no significant difference in rumen microbial Alpha diversity index,and there was no significant difference in bacterial community structure among all groups at phylum level（P>0.05）,while Prevotella＿1 showed a increasing trend at genus level（P<0.05）.Trial 3:Effects of completely mixed unconventional pellet feed on growth performance,nutrient digestion and blood biochemical indexes of finishing Hu sheep.In this experiment,80 fattening Hu sheep with body weight of（27.73±0.22）kg were randomly divided into 2 groups with 40 sheep in each group.Quarantine and deworming were carried out on Hu sheep before the experiment.The fertilizing Hu sheep in the control group were fed conventional pellet feed and freely fed peanut vine,while the Hu sheep in the experimental group were fed totally mixed unconventional pellet feed and freely fed peanut vine.The pre-feeding period lasted for 7 days and the test period lasted for 30days,during which the feeding was carried out at 7:30 and 14:30 every day.The experimental sheep were free to feed and drink.During the experiment,daily feed quantity and residual amount were recorded,and feed intake was calculated.During the last five days of the formal trial period,feed intake was recorded,fecal samples and feed samples were collected and sent to the laboratory for the determination of nutrient apparent digestibility by endogenous indicator method.On the last day of the experiment,Hu sheep blood was collected and sent to the laboratory for serum biochemical and immune indexes analysis.The results showed that final weight and ADG were increased by 40%,total dry matter intake（TDMI）and granule intake were significantly increased（P<0.001）,while coarse feed intake had no significant difference（P>0.05）,and the ratio of feed to gain（F/G）was decreased by 18.55%（P<0.001）,Gross profit increased by 1.59 yuan and gross profit margin increased by 43.61%.Dry matter digestibility was increased by 4.76%（P<0.05）,the digestibility of crude protein（CP）,neutral detergent fiber（NDF）and acid detergent fiber（ADF）in experimental groups was higher than that in control group,but the difference was not significant（P>0.05）;The contents of total cholesterol（TC）were significantly decreased（P<0.01）,and the contents of immunoglobulin A（Ig A）,immunoglobulin G（Ig G）and immunoglobulin M（Ig M）were significantly increased（P<0.05）.Trial 4:Effects of completely mixed unconventional pellet feed on rumen fermentation and rumen microflora of fattening Hu sheep.The experiment design and animal feeding management are the same as experiment 3.The results showed that the total mixture of unconventional pellets significantly increased rumen p H and the contents of isobutyric acid（IBA）and isovaleric acid（IV）（P<0.05）,while decreased NH3-N concentration（P<0.001）.It had no significant effect on the rumen microbial Alpha diversity index（P<0.05）.At the phylum level,the abundance of Firmicutes in control group was significantly higher than that in experimental group（P<0.05）,Bacteroidetes and Fibrobacteres,respectively.Patescietes,Spirochaetes and Planctomycetes were significantly lower than those in experimental group（P<0.05）,while no significant differences were found in other bacteria groups.The Prevotella＿1 in control group was significantly lower than that in experimental group（P<0.05）,but no significant difference was found in other bacteria（P>0.05）.Of the top 30secondary pathways,Rumen bacterial flora of Group C is involved in the Glycan biosynthesis and metabolism pathway and Biosynthesis of other secondary metabolites metabolites)pathway,Transport and catabolism pathway and Digestive system were significantly lower than those in test group（P<0.05）.Lipid metabolism pathway,protein Folding,sorting and degradation in the rumen bacterial community of control group sorting and degradation)pathway,Environmental adaptation and Membrane transport pathway were significantly higher than those of test group（P<0.05）;The p H was positively correlated with Prevotella＿1（R=0.78,P=0.003）,Eubacterium＿nodatum＿group（R=-0.59,P=0.041）,Sharpea（R=-0.60,P=0.038）had a negative correlation;NH₃-N and Ruminococcus＿1（R=-0.70,P=0.011）,Eubacterium＿ruminantium＿group（R=-0.77,P=0.003）and Fibrobacter（R=-0.77,P=0.003）showed a negative correlation,and had a positive correlation with Eubacterium＿nodatum＿group（R=0.70,P=0.010）.Valeric acid was negatively correlated with Rikenellaceae＿RC9＿gut＿group（R=-0.63,P=0.028）.The average daily gain was positively correlated with Ruminococcus＿1（R=0.59,P=0.043）and Rikenellaceae＿RC9＿gut＿group（R=0.76,P=0.004）.Feed/gain was negatively correlated with Rikenellaceae＿RC9＿gut＿group（R=-0.68,P=0.014）,concentrate intake was negatively correlated with Prevotella＿1（R=0.67,P=0.016）,Ruminococcus＿1（R=0.58,P=0.048）,Rikenellaceae＿RC9＿gut＿group（R=0.58,P=0.048）,Fibrobacter（R=0.87,P<0.001）,and Shuttleworthia（R=-0.68,P=0.015）,Eubacterium＿nodatum＿group（R=-0.87,P<0.001）,Ruminococcaceae＿UCG-014（R=-0.68,P=0.015）,Sharpea（R=-0.63,P=0.028）were negatively correlated;Coarse grain intake was negatively correlated with Prevotella＿1（R=-0.86,P<0.001）.Dry matter digestibility was positively correlated with Prevotella＿1（R=0.59,P=0.04）,Rikenellaceae＿RC9＿gut＿group（R=0.62,P=0.033）,and Ruminococcaceae＿UCG-014（R=-0.59,P=0.044）showed a negative correlation;Crude protein digestibility is positively correlated with Erysipelotrichaceae＿UCG-009（R=0.69,P=0.015）and Sharpea（R=0.59,P=0.044）.NDF digestibility is positively correlated with Fibrobacter（R=0.65,P=0.022）.There was a negative correlation with Ruminococcaceae＿UCG-014（R=0.36,P<0.001）.ADF digestibility Prevotella＿1（R=-0.70,P=0.011）.In conclusion,replacing corn concentrate with a variety of agricultural and by-products will make beef cattle diet palatability deteriorate,reduce feed intake,hinder growth performance,reduce dry matter digestibility,and reduce economic benefits.In this study,the use of total mixed diet granule technology to granulate agricultural and by-products for feeding Hu sheep can significantly improve feed intake,growth performance and nutrient digestibility of Hu sheep,improve the stability of rumen environment,solve the palatability problem in the application of agricultural and by-products,and greatly improve economic benefits.