Effects Of Inclusion Of Alfalfa Hay In Starter Diet On The Performances And Rumen Function Of Fattening Hu Sheep

The colonization pattern of rumen microflora and the development of rumen tissue in young ruminant have a long-term effect on adulthood,while different carbohydrate types in lamb starter could change the growth performance and ruminal microflora,but it is unknown whether growth performance and rumen function of sheep can be changed by offering starter diets with different carbohydrate type before weaning.The aim of this study was to explore the effects of different nutritional backgrounds in the early life of Hu lambs on its growth performance,digestibility of nutrient,rumen health,microorganism and fatty acid profiles of intramuscular lipids during the fattening period,and to provide theoretical guidance for the early nutritional regulation of rumen health of fattening Hu sheep.In this experiment,37 male lambs with similar genetic background were selected after born,and divided into 2 treatments and supplied diferent diets: starter concentrate with or without 10% alfalfa hay supplementation.In each group,lambs were housing together with their mothers to suck milk,and starter were provided after about 3 days intake of colostrum.Starter were provided until 77 d age of lambs(3 d-35 d for preweaning and 36 d-77 d for postweaning transition period),and then changed to a period feed the same fattening diet after 7 days adapting until the experiment finished.All lambs were transferred into individual pens after weaning in 35 d.The growth performances were measured in each period and did a digestion trial in vivo.After trial,all sheep were slaughtered and sampled.In addition,rumen fluid was obtained using a stomach tube in 4 time point:14 d before fattening(70 d)and 14 d(99 d),28 d(113 d),63 d(148 d)in fattening to explore the changes of volatile fatty acid and microflora in rumen.The main results are as flows:1.At the pre-weaning period,lambs in Alfalfa group has the higher ADG(P<0.05).At the transition period(35 d-77 d),lambs in Alfalfa group has the higher DMI,ADG,final body weight(77 d)and feed conversation rate(P<0.05).The ADG,final body weight(148 d)was higher in Alfalfa group in fattening period.3.The number of R.albus,F.succinogenes,B.fibrisolvens and S.ruminantium was significantly higher(P<0.05)in Alfalfa group compering with Control at 70 d.Moreover,the number of F.succinogenes and B.fibrisolvens was increased with the increasing of fattening diet intake(P<0.05).The interaction of fattening time and treatment has a significant effect on the number of R.albus and F.succinogenes(P<0.05).The supplementation of alfalfa hay in Hu lambs’ starter could significantly increase the relative abundance of phylum Bacteroidetes(P=0.011)but decrease the abundance of phylum Firmicutes(P=0.001)and the ratio of phylum Firmicutes to Bacteroidetes(P=0.001).The treatment had no effects on the abundance of phylum in rumen at 148 d(P<0.05).4.The concentration of total VFA and the proportion of butyrate in rumen of sheep in Alfalfa group was significantly lower than Control(P<0.05),the concentration of total VFA and the proportion of acetate,isobutyrate,isovalerate and the ratio of acetate-to-propionate was increased(P<0.05)but the proportion of propionate,butyrate and valerate was decreased(P<0.05)with extension of fattening time(P<0.05).The interaction of fattening time and treatment has significant effect on the concentration of total VFA and the proportion of each VFA.The proportion of iso C16:0,iso C18:0 in muscle of fattening Hu sheep in Alfalfa group was significantly lower than control(P<0.05),and the proportion of C18:2 n-6c,C20:2 and UFA was tend to be lower in alfalfa group(P<0.5).In summary,the Hu sheep that feed starter with alfalfa supplementation in early life has an advantage of growth performance in preweaning,postweaning transition period and fattening period,and was good at rumen development,but weak in apparent digestibility of individual nutrient comparing with Control.Supplementation of alfalfa hay in starter of early stage could change the microbial community,increased the number of cellulolytic bacteria in rumen of fatten Hu sheep,and decreased the proportion of several branched chain fatty acid in muscle.