Study On The Application Of Branches And Leaves Of Mulberry In Beef Cattle Diet

In recent years,with the improvement of people's living standards,people's demand for livestock and poultry aquatic products is increasing rapidly,and the scale of development of animal husbandry is growing day by day.The shortage of feed sources has become one of the bottlenecks in the development of animal husbandry,China needs a large number of imported feed grains every year,which seriously affects the food security of China.Therefore,it is particularly important to develop indigenous feed sources.Mulberry is widely planted in China.Branches and Leaves of Mulberry(BLM),as a new unconventional feed resource,has the characteristics of strong environmental adaptability,high feed value and so on.At present,there have been a lot of studies on BLM used in livestock and poultry aquatic feed,but little research has been done on its digestibility and the effects on intestinal(rumen)microorganisms of livestock and poultry animals.In this paper,the effects of Grinding mulberry branches(GMB)and puffing mulberry branches(PMB)on degradation characteristics of rumen of beef cattle were studied.Taking Branches and Leaves of Mulberry Powder(BLMP)as the material,the optimal amount of BLMP in beef cattle diet was determined by feeding experiment,and the effects of BLMP on blood biochemical parameters of beef cattle were discussed.On this basis,the effects of BLMP on rumen microflora of beef cattle were studied in order to provide an important reference for the application of BLM feed in beef cattle diet.The main findings are as follows:1.Evaluation on feeding value of mulberry branches with different processing methods in beef cattle dietSix Yunnan Yunling fistula cattle weighing(400 ± 20)kg aged 30 months were selected as experimental animals.After the determination of the nutrient content and feed rating Guangxi hybrid mulberry cut-off branches.The degradation rates of Dry matter(DM),Organic matter(OM),Crude protein(CP),Neutral detergent fiber(NDF)and Acidic detergent fiber(ADF)of Guangxi hybrid mulberry cut-off branches were determined by nylon-bag method.The results showed that the CP content of GMB and PMB was 7.43 % and 7.97% respectively.Compared with GMB,the content of CP in PMB was significantly increased(P<0.01),and the contents of CF,NDF and ADF were significantly decreased(P<0.01).The feed grade of PMB was 3,which was higher than that of GMB.The degradation rate of different nutrients in rumen of PMB was significantly higher than that of GMB(P<0.01),which indicated that the CP content of winter mulberry branches of Guangxi hybrid was higher and had great potential in feed utilization.The nutritional value and degradation rate of PMB were better than those of GMB,and the Effective degradability(ED)of PMB was close to that of Leymus chinensis,which indicated that puffing technology was an effective processing method for BLM and PMB could be used as roughage in ruminants.2.Effects of Branches and Leaves of Mulberry Powder on growth performance and blood biochemical parameters of beef cattle18 24-month-old Yunling castrated cattle and 24 20-month-old Yunling cattle were selected respectively.According to the principle of complete random combination,the two groups of beef cattle were divided into three groups respectively.Each group was randomly treated with a diet,and two feeding experiments of BLM were conducted.The first stage was low mulberry group,middle mulberry group and high mulberry group.The second phase was control group(CON),alfalfa hay group(AH)and BLMP respectively.Dietary energy and protein nutrition levels were consistent in each group.The growth performance and blood biochemical parameters were measured by feed grade evaluation and feeding test.The results showed that:(1)The relative value of BLMP feed was higher than AH.(2)In the first feeding experiment,the average daily gain of middle mulberry group was significantly higher than that of low mulberry group(P<0.05),and the feed to gain ratio of middle mulberry group was significantly lower than that of low mulberry group(P<0.05),but there was no significant difference between middle mulberry group and high mulberry group(P>0.05).The results of the second phase showed that BLMP group had the lowest feed to gain ratio and was significantly lower than CON group(P<0.05).(3)The content of high density lipoprotein(HDL),Total cholesterol(TC)and Blood urea nitrogen(BUN)were significantly increased in BLMP group(P<0.01).The quality of BLMP feed was better than AH.Considering the growth performance and economic cost,2kg BLMP was determined to be the best addition amount in beef cattle diet,which could significantly reduce the beef cattle Feed to gain ratio,improve feed conversion rate and significantly increase HDL content in beef cattle blood.3.Effects of Branches and Leaves of Mulberry Powder on rumen microflora of beef cattleSix healthy Yunnan Yunling cattle with permanent rumen fistula weighing(400±20)kg were used as experimental animals,and divided into control period and experimental period by self-control method.2kg BLMP was added to the diet in the experiment period,but not in the control period.All of them were fed continuously for 30 days.The rumen fluid samples were collected on the last day of each phase,and all bacteria in rumen fluid were investigated by Miseq high-throughput sequencing and Quantitative real-time PCR,and gene function was predicted and analyzed by Phylogenetic Investigation of Communities by Reconstruction of Unobserved States(PICRUSt).The results showed that BLMP significantly affected rumen microflora by ? and ? diversity analysis.From the community composition analysis,182 genus belonging to 19 phylum were detected in all rumen fluid samples.The ratio of Bacteroidetes and Firmicutes was the highest at the phylum level.Compared with the control group,BLMP decreased the proportion of Bacteroidetes by 8.36%(P>0.05),increased the proportion of Firmicutes and Fibrobacteres by 1.82% and 70.59%(P>0.05),and increased the proportion of Spirochaetes by 105.17%(P<0.01).In the genus level,the proportion of the Fibrobacter increased by 71.43%(P>0.05),and the proportion of the butyrivibrio increased by 151.52%(P<0.05).At the species level,the number of Fibrobacter succinogenes increased by 37.84%(P<0.05).The potential function of rumen bacteria was predicted by RICRUSt.It was found that the proportion of functional gene family of rumen bacteria changed significantly and carbohydrate-related gene was expressed in high quantity.The results showed that the addition of 2kg BLMP to diet had significant effects on the diversity and metabolic function of rumen microbial community,especially the increase of the proportion of major fiber-degrading bacteria might promote the degradation of plant cellulose and carbohydrate.In conclusion,the CP of PMB is higher and ED is close to Leymus chinensis,which indicates that puffing technology is an effective method for mulberry branches feed utilization,and PMB can be used as roughage in beef cattle breeding.BLMP can replace some concentrate.The optimal amount of BLMP in beef cattle diet is 2kg,which has a good effect on the health of beef cattle,and significantly affects the rumen microbial community and metabolic function,and has the effect of promoting the degradation of plant cellulose and carbohydrate.