| In this experiment,the effects of phytase combined with probiotics on production performance,egg quality,nutrient digestibility,tibial calcium and phosphorus,emission of nitrogen and phosphorus and ammonia and serum indexes of laying hens were studied.The effects of phytase combined with probiotics on production performance and reducing nitrogen and phosphorus emission of laying hens were preliminarily discussed.To determine the appropriate amount of phytase and probiotics in the diet of laying hens can provide the basis for the production practice of laying hens.A total of 1056 healthy 70 weeks Jingfen laying hens with no difference in laying rate were randomly divided into 11 treatments with 6 replicates in each treatment and 16 hens in each replicate.Treatment 1 was a positive control,fed with basal diet(normal phosphorus and protein levels);treatment 2 was negative control,fed with phosphorus-low and protein-low diet;treatments 3～11 were experimental Treatment,which were supplemented with different levels of phytase(500 U/kg,1 000 U/kg,10 000 U/kg)×probiotics(0.1 g/kg,0.5 g/kg,1.0 g/kg)on the basis of phosphorus-low and protein-low diet.The experimental period was 8 weeks,in which the adaptation period was 1 week and the main expermental period was 7 weeks.The results showed as follow:1)Production performance:① phytase supplementation in phosphorus-low and protein-low diet had no significant effect on production performance(laying rate,average daily feed-intake,average egg weight,feed/egg ratio)(P>0.05).② The feed/egg ratio of 1.0 g/kg probiotics group was significantly lower than that of positive control,negative control and 0.1 g/kg probiotics group(P<0.05).③ There was significant interaction between phytase and probiotics on laying rate and feed/egg ratio(P<0.05),but there was no significant difference between the 3 treatments and negative control(P>0.05),and there were significant differences between the other experimental Treatment and the negative control(P<0.05).The feed/egg ratio of experimental groups and positive control was significantly lower than that of negative control(P>0.05),and that of 8 treatment was significantly lower than that of positive control(P<0.05).2)Egg quality:phytase and probiotics had no significant effect on egg quality of laying hens with phosphorus-low and protein-low diet(P>0.05),and there was no significant interaction between phytase and probiotics on egg quality.(P>0.05).3)Apparent digestibility of nutrients:① Phytase supplementation in phosphorus-low and protein-low diet significantly increased calcium and phosphorus digestibility(P<0.05).The calcium digestibility of 1 000 U/kg phytase group was significantly higher than that of the positive control(P<0.05),but there was no significant difference between the experimental Treatment;the apparent phosphorus digestibility of 1 000 U/kg and 10 000 U/kg phytase Treatment was significantly different from that of positive control and 500 U/kg phytase group(P<0.05).②The protein digestibility was significantly increased in phosphorus-low and protein-low diet supplemented with probiotics(P<0.05).The protein digestibility of 0.5 g/kg and 1.0 g/kg probiotics Treatment was significantly higher than that of positive control and negative control(P<0.05),and that of 1.0 g/kg probiotics group was significantly higher than that of 0.1 g/kg probiotics group.③There was significant interaction between phytase and probiotics on phosphorus and protein digestibility(P<0.05).The phosphorus digestibility of the experimental groups was significantly higher than that of the negative control(P<0.05),and the protein digestibility of the 8th groups was significantly higher than that of the positive control(P<0.05),and there was no significant difference between the experimental treatment(P>0.05);the protein digestibility of the 8th group was significantly higher than that of the positive control,the negative control(P<0.05),and the 3th group.There was a significant difference between the 4th group and other experimental Treatment(P>0.05).4)Tibial calcium and phosphorus:There was no significant effect of phytase and probiotics on calcium and phosphorus in tibia(P>0.05).There was no significant interaction between phytase and probiotics(P>0.05).5)Emission of nitrogen,phosphorus and ammonia:① Phytase supplementation in phosphorus-low and protein-low diet significantly reduced nitrogen and phosphorus emission(P<0.05).The phosphorus emission of 1 000 U/kg and 10 000 U/kg phytase Treatment was significantly different from that of positive control,negative control and 500 U/kg phytase group(P<0.05).The nitrogen emission of the experimental group was significantly lower than that of the positive control(P<0.05),and that of the 10 000 U/kg phytase group was significantly lower than that of the negative control group and the 500 U/kg phytase group.②The addition of probiotics to phosphorus-low and protein-low diet significantly reduced nitrogen emission(P<0.05).The nitrogen emission of the experimental group was significantly lower than that of the positive control(P<0.05),and that of the 1.0g/kg probiotics group was significantly lower than that of the negative control group and 0.5g/kg probiotics group(P<0.05).③ There was significant interaction between phytase and probiotics on the excretion of nitrogen,phosphorus and ammonia(P<0.05).The phosphorus emission of the 6th groups,the 8th group,the 11th group were significantly lower than the positive control group,negative control group,the 3rd group,the 5th group(P<0.05).The nitrogen emission of the experimental group was significantly lower than that of the positive control,the 8th group,the 10th group,the 11th groups were significantly lower than those of the negative control,the 11th group were significantly lower than those of the 3rd group(P<0.05).The ammonia emission of experimental groups was significantly lower than that of the positive control(P<0.05),and there was no significant difference between the experimental Treatment(P>0.05).6)Serum biochemical indexes:① Phytase supplementation in phosphorus-low and protein-low diet significantly affected serum phosphorus content and AKP activity(P<0.05).The serum phosphorus content of 1 000 U/kg phytase group was significantly higher than that of the positive control,negative control and 500 U/kg phytase group(P<0.05).AKP activity in 1 000 U/kg and 10 000 U/kg phytase Treatment was significantly lower than that in positive control,negative control and 500 U/kg phytase group(P<0.05).② Phytase supplementation in phosphorus-low and protein-low diet had no significant effect on serum calcium,serum phosphorus,total protein content and AKP activity(P>0.05).③ There was significant interaction between phytase and probiotics on serum phosphorus content and AKP activity(P<0.05).The serum phosphorus content of the 3rd group was significantly lower than that of the positive control group,and there was no significant difference between the other experimental Treatment and the positive control.The serum phosphorus content of the 7th group and the 8th group were significantly higher than those of the three Treatment.AKP activity of the 7th group and the 8th group were significantly higher than those of the positive control,the negative control,the 3rd group,and the 4th group(P<0.05).7)According to the quadratic curve of phosphorus-emission,it was estimated that the best additive group was the 8th group.According to the fitting quadratic curve of nitrogen-emission,it was estimated that the best additive group was the 11th group.8)According to the calculation of economic benefit,it can get better economic benefit when laying hens are fed with phosphorus-low and protein-low diet supplemented with phytase 1 000 U/kg and 1.0 g/kg.In conclusion,it is better to add 1 000 U/kg phytase+1.0 g/kg probiotics in the phosphorus-low and protein-low diet,which can improve the production performance,improve the nutrient digestibility,reduce the emission of nitrogen,phosphorus and ammonia,and improve the economic benefits. |
PDF Full Text Request