Effect Of Yeast Culture On Nutritional Stress Relief In Broilers

The paper mainly studied the effect of yeast culture on growth performance, immunologic function and digestion function in broilers fed wheat diets,which contain different level soluble non-starch polysaccharide(sNSP),as a nutritional stress factor.It also was investigated the mechanism of YC on nutritional stress relief in broilers. Experiment 1:640 one-day-old AA broilers with the same weight were used to investigate the effect of YC on performance of broilers fed diets with different level wheat,and try to confirm the suitable including rate of YC in the diet with certain level wheat.The birds were randomly assigned to four groups,160 birds each group.The basal diets with different level YC (0,0.15%,0.3%,0.45%) were used for each group repectively during 1~21d.On the day 21,the broilers in each group were divided into four treatment groups(three repetition in each treatment group) and then were feed the diets with different level wheat,but keep same including rate YC with fisrt stage in the group on 21~42d.The result indicated no significant difference on daily feed intake,daily weight gain and feed efficiency between the dietary 15%wheat group and the corn control diet group(P>0.05).The 30%wheat group showed less affection than the 45% wheat group.The 45%wheat group was lower significantly than corn control diet group(P< 0.05) on daily feed intake and Feed/Gain(P<0.01).Daily Weight Gain of 45%wheat group reduced obviously whereas the number of diarrhea broilers increased when it compared with corn control diet group.After added 0.45%YC to the diet which included 45%wheat,daily feed intake increased and daily weigt gain,feed efficiency improved significantly whereas the number of diarrhea broilers decreased compared with 45%wheat group.It was suggested that supplied 0.45%YC in the diet with 45%wheat may relief the nutritional stress from the NPS in the wheat.Experiment 2:The experiments were conducted to investigate the action mechanism of YC on broilers under nutritional stress from wheat diet.270 one-day-age AA broilers randomly assigned to six groups.Six diets were designed,Corn basal diet,corn basal diet +YC,corn basal diet +E,wheat diet,wheat diet +YC and wheat diet +E.Three replicates each group and 15 birds each replicate.The experiment was divided into two stages.The broilers were feeded basal diet on l~7d and experimental diet on 7~49d.The result showed:The daily weight gain increased significantly when 0.05%E was added to the diet included 45%wheat compared with 0.45%YC group and 45%wheat group(P<0.05),the daily weight gain of the wheat+0.45%YC group increased significantly compared with the 45%wheat group.The feed effciency of wheat +YC group and wheat +E group increased significantly compared with 45%wheat group(P<0.05). The feed effciency of corn basal+YC group and corn basal +E group increased significantly compared with Corn basal group(P<0.05).After YC and E were added respectively in the wheat group,crude protein and crude fat apparent metabolism rate increased significantly (P<0.05).The apparent metabolism rate of phosphorus increased significantly in the wheat+E group(P<0.05).The food pass rate in digestive tract and the quantity of beneficial bacterias in caecum were increased when YC and E were added respectively in the wheat group(P< 0.05),but the water ratio in excrement of broilers decreased significantly(P<0.05).After YC was added in 45%wheat group,relative weight of spleen,thymus and the bursa increased in some certain extent compared with the wheat group.On 21d,The total protein and the globulin content of Corn basal +YC group increased respectively 2.94%and 25.49%(P<0.05) compared with corn basal group;The total protein and globulin content of Corn basal +E group increased respectively 2.19%and 10.71%(P<0.05) compared with corn basal group.After YC and E was added in the wheat diet treatment groups,the total protein and the albumin content increased compared with the wheat group.On 49d,the total protein and the albumin content of corn basal +E group increased highly significant compared with corn basal group,(P<0.01),the total protein and the albumin content of corn basal +YC group increased significantly compared with corn basal(P<0.05);In the wheat diet treatment groups,the total protein and the albumin content of wheat +YC group increased highly significant compared with wheat group(P<0.01) and significant compared with wheat+E group(P<0.05) The result above showed that the growth performance,immunity ability,digestion function and stability of intestinal tract environment of the broilers which under the stress condition could be improved by adding YC in diet,indicated that YC had the relief function on broilers the nutritional stress.