Effects Of Dietary Concentrate To Forage Ratio On Growth Performance And Rumen Metabolism Of Sheep And Goats

Diets and species are important factors affecting the rumen microflora.Roughage stimulates rumen development,and concentrated feed is decomposed by rumen flora to provide a large amount of energy for the body.50-70% of the protein requirements and more than 70% of the energy requirements of ruminants are met by the metabolism of rumen microbes.This experiment combines amplicon sequencing,host growth and digestion performance and metabolomics to explore the influence of host and dietary factors on the composition and diversity of rumen flora,as well as the impact on host metabolism.The experiment selected 5 month old small-tailed Han sheep rams and 5 Boer goat rams,with an average weight of 33.87±1.70 kg.They were divided into group S(small-tailed Han sh eep)and group B(Boer goat).Two diets were formulated that the concentrate-roughage ratio of 3:7 and 5:5,respectively.The experiment was divided into three periods in turn,the period X was fed with a ratio of concentrate to roughage of 3:7 diet(divided into XS group and XB g roup),and period Y was fed with a ratio of concentrate to roughage of 5:5 diet(divided into Y S group and YB Group),period Z resume feeding the diet with a ratio of concentrate to rough age of 3:7(divided into ZS group and ZB group),each period is 28 days and the feeding cond itions of the two groups were the same.In each period,growth and digestion indexes,serum b iochemical and hormonal indexes were determined.Collect rumen fluid sample for 16 S r DNA sequencing,VFA determination and metabolome test.Collect serum sample for metabolome test.The results of the growth and weight gain index showed that under the same feeding con ditions,the average daily gain of the small-tailed Han sheep group was lower than that of the Boer goat group,but there was no significant difference.The ratio of dietary concentrate to ro ughage has varying degrees of influence on the average daily gain and feed/ gain ratio of the s ame sheep group.The feed/ gain ratio in the period Y is significantly lower than that in the pe riod Z,and there is no significant difference between the period X and the period Z.The result s of the apparent digestibility of nutrient ingredients showed that the apparent digestibility of acid detergent fiber between the XS group and the XB group showed a significant difference,and the XS group was higher.Serum indexes results showed that the ALT content of group B in the three periods was significantly higher than that of group S.The ratio of concentrate to roughage had an effect on serum indexes.The contents of Glu,TG,Urea,AST and Ins were significantly difference among XS,YS,and ZS groups.The content of Glu,Urea,and AST were significantly difference among XB,YB,and ZB groups.The results of rumen fermentation parameters showed that there was no significant difference in the p H of rumen liquid between XS vs.XB and ZS vs.ZB.The p H of the YB group was significantly higher than that of the YS group.XB group was significantly higher than that of the XS group on the level of total volatile fatty acid,and XB group was significantly higher than that of the XS group on the acetic acid level of rumen fluid.The p H,total VFA level,and propionic acid level all showed significant differences among XS,YS,and ZS groups.The level of total VFA,acetic acid and propionic acid also showed significant difference among XB,YB and ZB groups.And XB group is the highest;YB group is the lowest among all the levels of index.The 16 S r DNA sequencing results showed that at the parameters of alpha diversity analysis,the observed species,shannon and chao1 indicators all have significant difference between XS and ZS group.Compared with the XB group,the relative abundance of Proteobacteria,Gammaproteobacteria,Aeromonadales,Succinivibrionaceae,Succinivibrionaceae＿UCG-001 and Succinivibrio were significantly higher in the XS group.Compared with the YB group,the relative abundance of Proteobacteria,Gammaproteobacteria,Aeromonadales,Succinivibrionaceae,Prevotellaceae＿UCG-001,Shuttleworthia,Syntrophococcus and Schwartzia has significantly higher level in the YS group,and the bacteria with higher relative abundance in YB group included Oscillospirales,RF39,Ruminococcaceae,Quinella.The metabolomics results showed that D-glucosamine 6-phosphate of rumen fluid in XB group was higher than that in XS group,and N6,N6,N6-Trimethyl-L-lysine,adenosine 5’-monophosphate,inosine 5’-monophosphate,N6-acetyl-L-lysine,guanosine monophosphate,spermidine,xanthosine,spermine,D-Ribulose 5-phosphate,L-Histidine and D-sedoheptulose7-phosphate in YB group all were higher than those in YS group.During X and Y periods,the threonine level of S group was higher and levels of caprylic acid,capric acid and lauric acid were higher in the B group in serum.In conclusion,the host species and the ratio of dietary concentrate to roughness affect the abundance and diversity of rumen bacteria.After ceasing dietary intervention,the rumen flora will not recover to the original structure.The feed efficiency of small-tailed Han sheep is higher than that of Boer goats,and Succinivibrionaceae may be the specific flora related to small-tailed Han sheep.Differential metabolite suggests that the metabolic pathways of different genera in the same family have obvious difference.The amino acid metabolism,nucleotide metabolism are more active in the rumen fluid when the ratio of concentrate to roughage was 5:5.