Effects Of Total Mixed Diet Added With Yeast And Lactose On Growth Performance Blood Index And Rumen Fermentation In Ewe

The objectives of this study were to investigate the effects of adding yeast and lactose to a total mixed diet（TMR）on the growth performance,blood biochemical indicators,rumen fermentation and rumen microflora in breeding ewes,so as to provide a theoretical basis for its application in production practice.Thirty healthy and disease-free ewes in similar age and body weight were selected and randomly divided into three groups,i.e.the control group,the yeast group and the lactose group.The control group was fed a total mixed diet,and the yeast and lactose groups were fed the total mixed diets added with 0.5%yeast and 1%lactose,respectively.The study lasted for 64 days with 14 days for adaptation and another 50 days for sampling.During the sampling period,body weight measurement and sample collection were carried out.The study consisted of four experiments:Experiment 1:The effects of total mixed diets added with yeast and lactose on the growth performance in ewes.The results showed that the initial weight,The lactose group was compared with the control and yeast groups,Significantly improved average daily and net weight gain for ewes（P<0.05）,Poor growth performance difference in yeast group versus control group（P>0.05）.Experiment 2:The effects of total mixed diets added with yeast and lactose on the serum bio-indexes in ewes.Blood samples from the jugular vein of ewes were collected.No significant differences（P>0.05）were observed among treatments in the serum concentrations of glucose（GLU）,triglyceride（TG）,total cholesterol（TC）,alanine aminotransferase（ALT）,aspartate aminotransferase（AST）,alkali phosphatase（ALP）,total protein（TP）,and albumin（ALB）.UREA in the lactose group serum was significantly lower than in control and yeast（P<0.05）and less differences in control and yeast（P>0.05）Experiment 3:The effects of total mixed diets added with yeast and lactose on rumen fermentation in ewes.Rumen fluid samples were taken separately from animals of all groups and rumen fermentation parameters were determined.The results showed that rumen p Hs were similar among treatments and ammonia nitrogen（NH₃-N）concentrations of animals from the yeast group and lactose group were similar（P>0.05）but were significantly lower than that from those in the control group（P<0.05）;rumen concentrations of the acetic acid（AA）,propionic acid（PA）butyric acid（BA）and total volatile fatty acid（TVFA）were significantly higher（P<0.05）in the animals from the lactose group when compared to those from the yeast and control groups.No significant differences（P>0.05）were observed among treatments in the rumen concentrations of isobutyric acid（IBA）,valeric acid（VA）and isovaleric acid（IVA）as well as the ratio of ethylene-to-propylene.Experiment 3:The effects of total mixed diets added with yeast and lactose on rumen microflora in ewes.Rumen fluids were collected from animals in the three groups,and 16S r RNA gene high-throughput sequencing technology was used to analyze the rumen diversity of microbial flora.The results showed that:1)At the phylum level,Bacteroidetes,Firmicutes,Proteobacteria,and Actinobacteria are the dominant phyla.Compare to the control group,adding yeast and lactose to the TMR did not significantly change（P>0.05）the relative abundance of rumen microrganisms;2)At the genus level,Prevotella＿7（Prevotella＿7）,Prevotella＿1（Prevotella＿1）and Prevotella＿1 Prevotellaceae＿UCG-001（Prevotellaceae＿UCG-001）were the dominant genus.Compared to the control group,adding yeast and lactose to the TMR did not significantly change（P>0.05）the relative abundance of rumen microrganisms.The above results show that 0.5%active yeast and 1.0%lactose respectively were added to fully mixed grain diet,significantly reduce the concentration of ammonia nitrogen（NH₃-N）in tumor stomach,can significantly increase the average daily weight and net gain of ewe,significantly improve the concentration of acetic acid,propionic acid,butyric acid and total volatile fatty acids,improve the fermentation function of sheep,and reduce the concentration of UREA in serum.However,there had no significant impact on other serum indicators and the structure of neogastric flora.