Effects Of Fermented Mulberry Branches And Leaves On The Production Performance,nutrient Apparent Digestibility And Fecal Microbial Flora In Growing Pigs

Fermented mulberry branches and leaves（FML）is a kind of feed material made of leaves,buds and some tender branches of mulberry plants as the main raw materials by using microbial solid state fermentation technology.In order to clarify the nutritional value of fermented mulberry branches and leaves,this study analyzed the p H value,nutrient composition and effective viable bacteria number of fermented mulberry branches and leaves,and screened the fermented mulberry branches and leaves processed by 80 cm cutting mulberry branches and leaves for growing pig feeding experiment.Then,the effects of different levels of fermented mulberry branches and leaves on the production performance,nutrient apparent digestibility and fecal microflora of growing pigs were investigated.Firstly,the p H and conventional nutrient composition of fermented mulberry branches and leaves with cutting heights of 70 cm（Ⅰ）,80 cm（Ⅱ）,90 cm（Ⅲ）and 100 cm（Ⅳ）were determined by chemical analysis method.Then,by comparing the results of various nutrient indexes and combining with the actual production,a relatively good quality fermented mulberry branch and leaf was selected as the research material,and the sample was taken to continue to determine the content of amino acids and the number of effective viable bacteria in the fermented mulberry branch and leaf.In the animal feeding experiment,sixty healthy and similar growing pigs with the same initial body weight of（20.0±3.0）kg were randomly divided into four groups with five replicates and three pigs in every replicate.The control group（CON group）was fed a basal diet,and the FML＿6,FML＿9 and FML＿12 groups were fed diets containing 6%,9%and12%fermented mulberry branches and leaves,respectively.The diets of each group were equal energy and equal protein.The pre-feeding period of the experiment was 3 d,and the formal trial period lasted for 8 weeks.The main results are as follows:1.Nutritional value and quality analysis of fermented mulberry branches and leaves:（1）The p H of fermented mulberry branches and leaves of Nos.I,II,III and IV were4.09,4.41,4.39 and 4.19 respectively;The contents of crude protein were 20.9%,20.9%,14.7%and 6.9%respectively;The contents of crude fat were 2.5%,2.3%,2.9%and 1.5%respectively;The contents of crude fiber were 20.7%,26.8%,33.3%and 39.8%respectively;The contents of crude ash were 7.7%,9.6%,7.2%and 12.3%respectively;The contents of calcium were 1.2%,1.5%,1.6%and 0.6%respectively;The contents of total phosphorus were 0.3%,0.3%,0.3%and 0.2%respectively;The total energy was 17.6%,17.8%,20.0%and 16.8%respectively;The contents of neutral detergent fiber were 24.4%,32.2%,38.0%and 55.5%respectively;The contents of acid detergent fiber were 17.3%,23.6%,27.3%and47.4%respectively.The p H values of the four fermented mulberry branches and leaves were all below 4.5,indicating that the fermentation quality was good;Among them,the crude protein content of the fermented mulberry branches and leaves of No.Ⅰand No.Ⅱwas 20.9%,which was significantly higher than that of the fermented mulberry branches and leaves of No.ⅢandⅣ.With the increase of cutting height,the content of crude fiber,neutral detergent fiber and acid detergent fiber in fermented mulberry branches and leaves gradually increased.Combined with the production practice,the yield of mowing was relatively higher when mulberry leaf plant height was 80 cm than 70 cm.Therefore,this study screened No.II fermented mulberry branch and leaf for further determination and carried out the feeding experiment of growing pigs.（2）The content of amino acids in freshly fermented mulberry branches and leaves of No.Ⅱaccounted for more than 4.8%,of which the content of total essential amino acids was2.32%,accounting for 47.54%of the total amino acid.The content of lysine is 0.30%,accounting for 6.15%of the total amino acid.（3）The number of effective viable bacteria of lactobacillus,yeast,Bacillus subtilis and mold in No.Ⅱfermented mulberry branches and leaves were 1.02×10¹¹CFU/g,1.84×10¹³CFU/g,1.60×10¹¹CFU/g,0 CFU/g respectively.2.Production performance:Compared with the control group,the ADFI and ADG in group FML＿12 were significantly increased（P<0.01）,and the two indexes were increased by 13.64%and 16.09%,respectively,while the ADFI and ADG in groups FML＿6 and FML＿9 were not significantly different from that in the control group（P>0.05）.With the increase of dietary FML proportion,the ADFI and ADG of growing pigs in experimental groups showed quadratic changes（P<0.01）.The ratio of feed to gain（F/G）and diarrhea indexes of experimental groups had no significant effects（P>0.05）,but fermented mulberry branch and leaf supplementation tended to decrease diarrhea rate and diarrhea frequency of growing pigs（P<0.1）,and the diarrhea rate and diarrhea frequency were linearly decreased with the increase of FML supplemental level（P<0.05）.3.Nutrient apparent digestibility:Compared with the control group,the addition of fermented mulberry branches and leaves to the diet of growing pigs had no significant effect on the apparent digestibility of dietary crude protein,crude fat,crude fiber,crude ash,total phosphorus and calcium（P>0.05）.Compared with the CON group,the apparent digestibility of dry matter of group FML＿6 had no significant effect（P>0.05）,while the apparent digestibility of dry matter of groups FML＿9 and FML＿12 was extremely significantly decreased（P<0.01）;With the increase of FML supplemental level,the apparent digestibility of dry matter among experimental groups showed linear and quadratic changes（P<0.01）,and the apparent digestibility of crude protein and total phosphorus showed linear change（P<0.05）.4.Fecal microbiota:The addition of FML in the diet had no significant effect on Chao1index and Observed＿otus index（P>0.05）.Compared with the CON group,the Shannon index in group FML＿6 was significantly decreased（P<0.05）,and the Shannon index in group FML＿9 was extremely significantly decreased（P<0.01）.Compared with the CON group,the Simpson index in groups FML＿6 and FML＿9 was significantly decreased（P<0.05）.The Shannon index（P<0.01）and Simpson index（P<0.05）showed quadratic changes with FML supplemental level.At the phylum level,Firmicutes,Bacteroidota,Bacteroidetes and Actinobacteriota were the main dominant phylum.Compared with the CON group,the relative abundance of Actinobacteriota in groups FML＿6,FML＿9 and FML＿12 was significantly increased（P<0.05）,and the relative abundance of Spirochaetota was extremely significantly decreased（P<0.01）.With the increase of FML supplemental level,the relative abundances of Actinobacteriota and Spirochaetota among experimental groups showed linear and quadratic changes（P<0.01）.Compared with the CON group,the relative abundance of Bacteroidetes in groups FML＿6 and FML＿9 was extremely significantly decreased（P<0.01）,and the abundance of Bacteroidetes in experimental groups showed quadratic changes with the addition level of FML（P<0.01）.At the genus level,the main dominant genera were Streptococcus,Muribaculaceae＿unclassified,Megasphaera and UCG-005.Compared with the CON group,the relative abundance of Megasphaera in group FML＿9 was significantly increased（P<0.05）,and the abundance of Megasphaera showed a quadratic change with the proportion of FML supplementation（P<0.05）.Compared with the CON group,group FML＿12 significantly increased the relative abundance of UCG-005 and Prevotellaceae＿NK3B31＿group（P<0.05）,and extremely significantly increased the abundance of Clostridium＿sensu＿stricto＿1（P<0.01）.With the increase of dietary FML concentration,the relative abundances of UCG-005 and Clostridium＿sensu＿stricto＿1showed linear and quadratic changes（P<0.01）,and the relative abundances of Prevotellaceae＿NK3B31＿group showed linear（P<0.05）and quadratic（P<0.01）changes.In conclusion,the results of this study showed that the suitable cutting height of mulberry leaves was 70～80 cm,and the forage value of fermented mulberry branches and leaves collected at this height was relatively high.The addition of fermented mulberry to the diet can significantly improve the growth performance,reduce diarrhea,improve nutrient apparent digestibility and intestinal microflora diversity of growing pigs,and promote the proliferation of beneficial bacteria,and reduce harmful bacteria,which is beneficial to intestinal health.Under the conditions of this experiment,the addition of 0%～12%fermented mulberry branches and leaves in the diet has no adverse effect on the production performance of growing pigs.It can be added to the diet of growing pigs to partially replace feed materials such as corn soybean meal,so as to realize the reduction and replacement of corn soybean meal in the feed.