The Effects Of Yeast Concentrate On Nutrition And Metabolism With Supplentment Dietary Nutrition Levels Of Ross Broilers

In order to study the influences of adding ways and supplment levels in differentnutrition diet on production performance, enzyme activity, intestinal mucosa morphologyand serum biochemical index of Ross broilers.224one day-old Ross broilers were dividedinto7groups with4repeats and8broilers in each repeats. Group I as control group, fedbasic diet. Group II~VI were treat groups and fed0.2%,0.2%,0.4%,0.6%,0.8%yeastconcentrate in basic diet respectively，Group II additive0.2%Yeast concentrate from1to42days continuously and Group III~V added from day1to day22only，Group VII wasfed low-energy and low-protein diet with2.0g/kg yeast concentrate. The trial lasted for42days. The results showed that:(1) The effects of adding ways of yeast concentrate on Ross broilers.During day1to21,the ADG of group II、III、V were increased by9.84%（P＜0.05）,9.43%（P＜0.05）and15.86%（P＜0.05）compared with control group, the ADI improvedby10.54%（P＜0.05）,8.36%（P＜0.05）,9.15%（P＜0.05）,11.36%（P＜0.05）,6.11%（P＜0.05）,1.93%（P＞0.05）respectively. Feed/gain (F/G) were decreaed. The duodenumvillus height in Group I, III, IV, V, VI were increased by6.77%(P＜0.01),6.24%(P＜0.01),7.08%(P＜0.01),8.46%(P＜0.01) and6.12%(P<0.01)respectively. Villusheight/crypt depth(V/C) were increased18.00%(P＜0.01),19.17%(P＜0.01),20.94%(P＜0.01),21.91%(P＜0.01),15.26%(P＜0.01) and15.26%(P＜0.01)respectively. Comparedto control group, the T-SOD in group II, III, IV, V, VI were increased by27.80%(P＜0.05),28.70%(P＜0.05),32.30%(P＜0.05),33.00%（P＜0.05）,29.80%（P＜0.05）respectively.serum IGF-1were significantly increased（P＜0.05). There was no significant effect ondigestive enzyme activity.During day22to42, the ADG in group III, IV, V, VI were higher than control groupwhile the effect was the best on group V (6000mg/kg) which has no significant differencecompared with group II. Yeast concentrate increased V/C(P＞0.05) and digestive enzymesactivity（P＞0.05）and the level of serum IGF-1, there is no significant differences amongdifferent adding levels in different adding methods.(2) The effects of yeast concentrate added in different nutrition levels diet to Rossbroilers. In group fed with low nutrient level diet, yeast concentrate had no significant effectson the productivity in early-stage and a increased trendency in the late-stage（P＞0.05）.Yeast concentrate can reduce F/G and improve ADG（P＞0.05）in whole stage.Compared to group II, the ADG of group VII was decreased（P＜0.05) in the earlystage,and differences were not significant in the late stage.To summarize, yeast concentrate could remarkably improve the productivity, increasethe utilization rate of the nutrients, improve the intestinal mucosa structure and the increasedigestive enzymes activities and has a lag effect. The effect of adding yeast concentrate inlow-level ration is no significant differences. The proper additive dosage for Rose broilersis0.6%. The optimal way to add yeast concentrate is to add from day1to21, withdrawalfrom day22to42.