| This study consists of four experiments.Experiment one,the effects of low-protein diet supplemented with amino acids on the production performance and diarrhea rate of weaned piglets.Experiment two,the effects of low-protein diet supplemented with amino acids on the blood indexes and nutrient digestibility of weaned piglets.Experiment three,the effects of low-protein diet supplemented with amino acids on the Intestinal mucosal structure of weaned piglets.Experiment four,the large herd comparison in production performance and other indexes of weaned piglets fed with low protein and very low-protein diets supplemented with amino acids.Experiment 1,the effect of low-protein diets supplemented with amino acids on the production performance and diarrhea rate of weaned piglets.three hundred and twenty three-way cross [Duroc×(Landrace×Yorkshire)] piglets with body weight of 10 kg were selected and randomly divided into four treatments,each treatment with four repeats,every repeat twenty pigs.The control group was fed ordinary diet,the crude protein levels of ordinary diets were 20.1%,experimental group were fed low-peotein diets with 1.8%,5.2%,6.9% declined in protein levels respectively.The crude protein levels of experimental diets were 18.3%,14.9% and 13.2% respectively.The amino acid levels of each treatment reached or exceeded the standard of nutrient requirements of swine(NRC 1998).The experiment period lasted 24 days.Result,(1)Production Performance,ADG of 13.2%CP treatment was significantly lower than that of 20.1%CP treatment(P<0.05).ADFI and F/G of 18.3%CP、14.9%CP、13.2%CP were not significant different compared with 20.1%CP(P>0.05).(2)Diarrhea rate,The diarrhea rate of 20.1%CP was the highest and that of 13.2%CP was the lowest and significant difference existed between them(P<0.05).(3)The weight of longissimus muscle,the weight of longissimus muscle of 13.2%CP was not significant different compared with 20.1%CP(P>0.05).Conclusion,compared with 20.1%CP diet,the level of dietary crude protein decreased 5.2% and reached 14.9% dietary protein level,the production performance of piglets was not significantly influenced.However,the level of dietary crude protein decrease 6.9 % and the dietary crude protein level diet reached 13.2%,the ADG of piglet was significantly reduced.With the reduction of dietary crude protein level,diarrhea rate of piglets was also reduced.Experiment 2,the effect of low-protein diet supplemented with amino acids on the blood indexes and nutrients digestibility of weaned piglets.three hundred and twenty three-way cross [Duroc×(Landrace×Yorkshire)] piglets with body weight of 10 kg were selected and randomly divided into four treatments,each treatment with four repeats,every repeat twenty pigs.The control group was fed ordinary diet,experimental group were fed low-peotein diets with 1.8%,5.2%,6.9% declined in protein levels respectively.The amino acid levels of each treatment reached or exceeded the standard of NRC(1998).The experiment period lasted 24 days.Result,(1)Blood Biochemical Indexes,piglet’s blood urea content of 20.1%CP theatment was the highest and that of 13.2%CP was the lowest and significant difference existed between them(P<0.01).The TP,Albumin,Globulin,A/G,Blood glucose,Insulin,IgA,IgG and IgM of 18.3%CP,14.9%CP and 13.2%CP were not significant different compared with 20.1%CP.(2)Apparent digestibility of nutrients,The difference of DM digestibility was not significant among all groups.The digestibility of crude protein in 20.1%CP was the highest and that of 13.2%CP was the lowest and significant difference existed between above two treatments(P<0.05).The digestibility of Ca and P were not significant different among all groups.Conclusion,the level of dietary crude protein decrease 6.9 %,the DM、Ca、P digestibility of piglet were not significantly different.With the decrease of crude protein levels in diet,the piglet’s blood serum urea content and dietary crude protein apparent digestibility were also decreased(P<0.05).Experiment 3,the effects of low-protein diet supplemented with amino acids on the Intestinal mucosal structure of weaned piglets.one hundred and sixty three-way cross [Duroc×(Landrace×Yorkshire)] piglets with body weight of 10 kg were selected and randomly divided into two treatments,each treatment with four repeats,every repeat twenty pigs.The control group was fed ordinary diet(20.1%CP),experimental group was fed low-peotein diet with 6.9% declined in protein levels(13.2%CP).The amino acid levels of each treatment reached or exceeded the standard of NRC(1998).The experiment period lasted 24 days.Result,(1)Intestinal mucosa villus height,mucosal villus height in duodenum and in jejunum in 20.1%CP treatment was significantly lower than that in 13.2%CP treatment(P<0.01),mucosal villus height in ileum in 20.1%CP treatment was not significant different compared with 13.2%CP treatment.(2)The crypt depth,crypt depth in jejunum of 20.1%CP was the highest and that of 13.2%CP was the lowest and significant difference existed between them(P<0.01).(3)Intestines mucosal villus width,mucosal villus width in ileum of 20.1%CP was significantly lower than that of the 13.2%CP(P<0.01),and that in duodenum and jejunum of 20.1%CP was not significant different compared with 13.2%CP.(4)V/C,The V/C ratio in jejunum and duodenum of 20.1%CP was significantly lower than that of the 13.2%CP(P<0.01),the V/C ratio in ileum in 20.1%CP was not significant different compared with 13.2%CP.The results showed as follows,compared with 20.1%CP diet,the level of dietary crude protein decreased 6.9 %(13.2%CP)can significantly increase mucosal villus height and V/C ratio in duodenum and jejunum(P<0.05).Experiment four,the large herd comparison in production performance and other indexes of weaned piglets fed with low protein and very low-protein diets supplemented with amino acids.In order to study the effect of very-low protein diets(13.2%)supplemented with amino acids on the growth performance,blood indexes,apparent digestibility of nutrients and diarrhea rate of weaned piglets.the large herd of three hundred and twenty three-way cross [Duroc×(Landrace×Yorkshire)] piglets with body weight of 10 kg were selected and randomly divided into two treatments,each treatment with eight repeats,every repeat twenty pigs.The control group was fed low-peotein diet,experimental group was fed very-low-peotein diet.The amino acid level of each treatment reached or exceeded the standard of NRC(1998).The experiment period lasted 27 days.Result,(1)Growth Performance,ADG,ADFI and F/G of 13.2%CP was not significant different compared with 14.9%CP(P>0.05).(2)Blood Biochemical Indexes,piglet’s blood urea content of 13.2%CP was significantly lower than that of the 14.9%CP(P<0.01).(3)Apparent digestibility of nutrients,the digestibility of dietary crude protein in 13.2%CP was significantly lower than that of the 14.9%CP(P<0.01).(4)Diarrhea rate,the diarrhea rate of 14.9%CP was significantly higher than that of the 13.2%CP(P<0.05).Conclusion,compared with 14.9%CP diet,the production performance of very-low protein diet was not significantly different.Moreover,very-low protein diets can reduce piglet’s diarrhea rate,digestibility of dietary crude protein and blood urea content of piglets. |
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