Effects Of Dietary Supplementation With Crude Polysaccharides Isolated From Alfalfa On Performance, Egg Quality And Immune Indices Of Laying Hens

This study was designed to analyze the effects of polysaccharides isolated from alfalfa(ACPS) at different levels on production performance, egg quality, biochemical parameters and immune function of laying hens. We wanted to estimate the effects of ACPS and provide experimental evidence for reasonable utilization as a new additive in terms of laying hens. A total of Five hundred and forty aged 27-week-old Hy-Line Brown hens were randomly allocated to 6 groups with 6 replicates per group and 15 hens per replicate. Group 1 was control group. Groups 2 to 6 were fed diets supplemented ACPS at 250, 500, 1 000, 2 000 and 4 000 mg/kg, respectively. The experiment lasted 24 weeks. The results showed as follows:1 Effects of dietary supplementation with crude polysaccharides isolated from alfalfa on production performance and egg quality of laying hensCompared with the control group, 1) hens fed 500, 2 000 and 4 000 mg/kg ACPS significantly increased egg production during 1 to 8 weeks(P < 0.05). The groups that added with ACPS at 250, 500, 1 000 and 2 000 mg/kg increased egg production and decreased feed/egg during 9 to 16, 17 to 24 and 1 to 24 weeks(P < 0.05) while significantly enhanced total egg mass during 17 to 24 and 1 to 24 weeks(P < 0.05). However, there were no obvious effects between and among 250, 500, 1 000 and 2000 mg/kg ACPS groups. There was a negative correlation between egg production and feed/egg but positive between egg production and total egg mass; 2) diets supplemented with 250, 500 and 1 000 mg/kg ACPS significantly improved eggshell color and eggshell thickness at 8th, 12 th, 16 th, 20 th and 24 th weeks(P < 0.05); 3) diets ACPS added at 2 000 mg/kg increased eggshell strength at 6th, 20 th and 24 th week(P < 0.05), while significantly enhanced eggshell thickness at 8th, 12 th, 16 th, 20 th and 24 th week(P < 0.05), as well as significantly increased the albumen height and Haugh unit at 10 th, 12 th and 24 th week; There was a significantly positive correlation between albumen height and Haugh unit. These data suggest that the suitable amount of ACPS can enhance production performance and improved egg quality of laying hens.2 Effects of dietary supplementation with crude polysaccharides isolated from alfalfa on biochemical parameters of laying hensCompared with the control group, 4 000mg/kg ACPS group were significantly reduced the content of serum TP, ALB and GLB at 9th week. Hens fed 2 000 mg/kg ACPS group significantly higher the serum A/G ratio at 7th week(P < 0.05), however 500, 1 000 and 4 000 mg/kg ACPS groups reduced the serum A/G ratio at 8th week(P < 0.05). The layer diets supplemented with 250, 500, 1 000, 2 000 and 4 000 mg/kg ACPS had no significant effects on the activity of serum ALT and AST as well as on the level of serum TP, ALB, GLB and A/G at remaining weeks(P > 0.05). The result showed that the layer diets supplemented with ACPS had small effects on serum biochemical parameters.3 Effects of dietary supplementation with crude polysaccharides isolated from alfalfa on immunity indexes of laying hens1) the serum C3 of 1000 mg/kg ACPS group was significantly higher than the control group, 250, 500 and 4 000 mg/kg ACPS groups at 3th and 7th week(P < 0.05); 2) the serum IL-2 of 1 000, 2 000 and 4 000mg/kg ACPS groups were significantly lower the control group, 250 and 500 mg/kg ACPS groups at 3th week(P < 0.05), as well as the serum IL-6 at 16 th week(P < 0.05). Meanwhile the serum IL-10 of 2 000 and 4 000 mg/kg ACPS groups, respectively at 3th, 8th and 12 th week and at 7th and 14 th week was significantly lower than the control group and 250 mg/kg ACPS group(P < 0.05); 3) the content of serum NO at 1 000, 2 000 and 4 000 mg/kg ACPS groups were significantly lower than the control group, respectively at 3th, 5th, 8th, 9th, 10 th, 20 th week and at 3th, 7th, 8th, 9th, 10 th, 20 th week and at 3th, 8th, 9th, 20 th week(P<0.05); 4) the activity of serum i NOS at 1 000, 2 000 and 4 000 mg/kg ACPS groups were significantly higher than the control group, respectively at 1th, 9th, 10 th, 12 th, 16 th week and at 9th, 10 th, 24 th week and 9th, 24 th week(P < 0.05). The result revealed that hens fed diets supplemented 1 000 ACPS can significantly reduce serum NO concentration and increase serum i NOS activity, while 2 000 and 4 000 mg/kg can markedly decrease serum IL-10 and NO concentration and enhance serum i NOS activity. Thereby, ACPS adjust the body’s immune function by regulating the secretion of IL-10 and NO and the activity of i NOS.