| This study was conducted to investigate the effects of low-protein level and amino acid balance quantity of different types of diet on the production performance,egg quality,protein absorption and metabolism,serum biochemical indicators,nitrogen emissions,and economic benefits of laying hens.It explores the feasibility of corn-soybean mealcottonseed meal low-protein diet and corn-soybean meal-cottonseed meal-rapeseed meal low-protein diet for laying hens,and determines the protein level of different mixed meal low-protein diet,the number and proportion of amino acids that need to be balanced at different protein levels,revealing the relationship between reducing protein levels and balancing amino acids in different types of miscellaneous meal diets,provides scientific basis for the application of mixed meal type low protein diet.Experiment 1:Study on low-protein level and amino acid balance model of cornsoybean meal-cottonseed meal diet for laying hensA total of 504 healthy 400-day-old Hy-line Brown laying hens were randomly divided into 7 treatments using a two-factor experimental design with 6 replicates per treatment and 12 hens per replicate.Diet type was corn-soybean meal-cottonseed meal.The CP level of group 1(control group)was 15.5%.On the basis of control group,the CP levels of groups 2,3 and 4 were decreased by 1.5%and Met+Lys,Met+Lys+Thr,Met+Lys+Thr+Trp were balanced,respectively.The CP levels of groups 5,6 and 7 were decreased by 3%and Met+Lys,Met+Lys+Thr,Met+Lys+Thr+Trp were balanced,respectively.The experiment lasted 91 days.The results showed:1)Dietary CP level significantly affected laying rate and feed egg ratio(P<0.05).Amino acid balance quantity significantly affected egg production(P<0.05).Dietary CP level and amino acid balance quantity had significant interaction on laying rate and feed to egg ratio(P<0.05).Compared with the control group,there was no significant effect in the production performance indicators of groups 2,3 and 4,the laying rate of 5,6 and 7 groups decreased significantly(P<0.05),and the feed to egg ratio increased significantly(P<0.05).2)Dietary CP level and amino acid balance quantity had no significant effect on egg quality(P>0.05).Moreover,there was no significant interaction between dietary CP levels and amino acid balance quantity on egg quality(P>0.05).3)Dietary CP level significantly affected the apparent metabolic rate of CP(P<0.05).Amino acid balance quantity had no significant effect on the apparent metabolic rate of CP,energy and ash(P>0.05).Dietary CP level and amino acid balance quantity had significant interaction on apparent metabolic rate of CP(P<0.05).Compared with the control group,the apparent metabolic rate of CP in groups 2,3 and 4 was significantly increased(P<0.05).4)Dietary CP level significantly affected the serum total protein,albumin,and uric acid content(P<0.05).Dietary CP level and amino acid balance quantity had significant interaction on serum total protein,albumin,and uric acid content(P<0.05).Compared with the control group,the total protein and albumin contents in serum of groups 5,6,and 7 were significantly decreased(P<0.05).Compared with the control group,the serum uric acid content in groups 3,4,5,6,and 7 significantly decreased(P<0.05).5)Dietary CP level and amino acid balance quantity significantly affected the expression of PepTl,B0AT1,and CAT1 genes in the ileum of laying hens(P<0.05).Dietary CP level and amino acid balance quantity had significant interaction on the expression of PepT1,B0AT1,and CAT1 genes in the ileum of laying hens(P<0.05).Compared with the control group,the relative expression of PepT1,B0AT1,and CAT1 genes in the ileum of groups 5,6,and 7 significantly decreased(P<0.05).6)Dietary CP level and amino acid balance quantity significantly reduced nitrogen emission of laying hens(P<0.05).Dietary CP level and amino acid balance quantity had significant interaction on the contents of indole,skatole and ammonia in feces of laying hens(P<0.05).Compared with the control group,the content of indole in feces in groups 3,4,5,6 and 7 was significantly reduced(P<0.05),the content of skatole and ammonia in feces of groups 2,3,4,5,6 and 7 were significantly reduced(P<0.05).7)The economic benefits of groups 2,3 and 4 were higher than those of the control group,and the economic benefits of group 2 were the highest.In summary,under the conditions of this experiment,the corn-soybean mealcottonseed meal low-protein diet is feasible.The corn-soybean meal-cotton meal low protein diet with a CP level of 14.0%that balances Met+Lys can regulate the relative expression of amino acid transporter mRNA in the ileum,ensure normal protein demand and maintain normal production performance and egg quality of laying hens.At the same time,it can also reduce serum uric acid content,reduce indole,fecal odor,and ammonia content in feces,and improve economic benefits.The amino acid balance mode of this group is Lys:Met:Thr:Trp=100:47:71:16.Experiment 2:Study on low-protein level and amino acid balance model of cornsoybean meal-cottonseed meal-rapeseed meal diet for laying hensA total of 504 healthy 400-day-old Hy-line Brown laying hens were randomly divided into 7 treatments using a two-factor experimental design with 6 replicates per treatment and 12 hens per replicate.Diet type was corn-soybean meal-cottonseed meal-rapeseed meal.The CP level of group 1(control group)was 15.5%.On the basis of control group,the CP levels of groups 2,3 and 4 were decreased by 1.5%and Met+Lys,Met+Lys+Thr,Met+Lys+Thr+Trp were balanced,respectively.The CP levels of groups 5,6 and 7 were decreased by 3%and Met+Lys,Met+Lys+Thr,Met+Lys+Thr+Trp were balanced,respectively.The experiment lasted 91 days.The results showed:1)Dietary CP level significantly affected laying rate and feed egg ratio(P<0.05).Amino acid balance quantity significantly affected egg production(P<0.05).Dietary CP level and amino acid balance quantity had significant interaction on laying rate and feed to egg ratio(P<0.05).Compared with the control group,there was no significant effect in the production performance indicators of groups 2,3 4 and 7,the laying rate of 5,6 groups decreased significantly(P<0.05),and the feed to egg ratio increased significantly(P<0.05).2)Dietary CP level and amino acid balance quantity had no significant effect on egg quality(P>0.05).Moreover,there was no significant interaction between dietary CP levels and amino acid balance quantity on egg quality(P>0.05).3)Dietary CP level and amino acid balance quantity had significantly affected the apparent metabolic rate of CP(P<0.05).Dietary CP level and amino acid balance quantity had significant interaction on apparent metabolic rate of CP(P<0.05).Compared with the control group,there was no significant effect in the apparent metabolic rate of CP in groups 2,3,5 and 6,the apparent metabolic rate of CP in groups 4,7 was significantly increased(P<0.05).4)Dietary CP level significantly affected the serum total protein,albumin,and uric acid content(P<0.05).Amino acid balance quantity significantly affected the serum total protein content(P<0.05).Dietary CP level and amino acid balance quantity had significant interaction on serum total protein,albumin,and uric acid content(P<0.05).Compared with the control group,the total protein contents in serum of groups 5,6 were significantly decreased(P<0.05).Compared with the control group,the serum albumin content in serum of groups 6 significantly decreased(P<0.05).Compared with the control group,the serum uric acid content in groups 3,4,5,6,and 7 significantly decreased(P<0.05).5)Dietary CP level and amino acid balance quantity significantly reduced nitrogen emission of laying hens(P<0.05).Dietary CP level and amino acid balance quantity had significant interaction on the contents of indole,skatole and ammonia in feces of laying hens(P<0.05).Compared with the control group,the contents of indole,fecal odor,and ammonia in all experimental groups were significantly reduced(P<0.05).6)The economic benefits of groups 2,3 and 4 were higher than those of the control group,and the economic benefits of group 3 were the highest.In summary,under the conditions of this experiment,the corn-soybean mealcottonseed meal-rapeseed meal low-protein diet is feasible.The corn-soybean meal-cotton meal-rapeseed meal low protein diet with a CP level of 14.0%that balances Met+Lys+Thr can improve the apparent digestibility of CP in laying hens,ensure normal protein demand,and maintain normal production performance and egg quality.At the same time,it can also reduce serum uric acid content,reduce the content of indole,fecal odor,and ammonia in feces,and improve economic benefits.The amino acid balance mode of this group is Lys:Met:Thr:Trp=100:47:71:16.This study concludes that:the corn-soybean meal-cottonseed meal low protein diet is feasible.Balancing Met+Lys can reduce the crude protein level of the diet to 14.0%(1.5%lower than normal),and the amino acid balance mode is Lys:Met:Thr:Trp=100:45:54:15;the corn-soybean meal-cottonseed meal-rapeseed meal low protein diet is feasible.Balancing Met+Lys+Thr can reduce the crude protein level of the diet to 14.0%(1.5%lower than normal),and the amino acid balance mode is Lys:Met:Thr:Trp=100:47:71:16. |
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