饲粮添加5-氨基乙酰丙酸对肉鸡生长性能、血常规指标、免疫功能和肠道形态的影响

Effects of Dietary 5-Aminolevulinic Acid Supplementation on GrowthPerformance, Blood Routine Indices, Immune Function and IntestinalMorphology in Broilers

本试验旨在探究饲粮中添加5-氨基乙酰丙酸(5-ALA)对肉鸡生长性能、血常规指标、免疫功能和肠道形态的影响。选取300只1日龄爱拔益加(AA)肉公鸡随机分成5组,每组6个重复,每个重复10只鸡。各组分别饲喂5-ALA添加水平为0(对照)、15、30、45和60 mg/kg的饲粮,试验期为42 d。结果表明:1)与对照组相比,饲粮中添加5-ALA对肉鸡平均日增重(ADG)和平均日采食量(ADFI)无显著影响(P>0.05),但添加60 mg/kg的5-ALA能显著降低肉鸡料重比(F/G)(P<0.05);且随饲粮中5-ALA添加水平的增加,F/G呈线性降低趋势(P<0.05)。2)与对照组相比,饲粮中添加30、45和60 mg/kg的5-ALA能显著提高21日龄肉鸡血液中血红蛋白(HGB)含量;随饲粮中5-ALA添加水平的增加,21和42日龄肉鸡血液中HGB含量和红细胞数(RBC)呈线性升高趋势(P<0.05)。3)与对照组相比,饲粮中添加45 mg/kg 5-ALA显著提高了21日龄时肉鸡血清中免疫球蛋白M(IgM)和免疫球蛋白G(IgG)含量(P<0.05),饲粮中添加45和60 mg/kg 5-ALA显著提高了21日龄时肉鸡血清中补体3(C3)和补体4(C4)含量(P<0.05);且21日龄肉鸡血清中C3和C4含量呈线性升高趋势(P<0.05)。与对照组相比,饲粮中添加30和45 mg/kg 5-ALA显著提高了42日龄时肉鸡血清中免疫球蛋白A(IgA)、IgM和IgG含量(P<0.05);饲粮中添加5-ALA显著提高了21日龄时肉鸡血清中干扰素-γ(INF-γ)含量(P<0.05)。4)与对照组相比,饲粮中添加5-ALA显著提高了21日龄肉鸡肝脏鸡源Cathelicidins抗菌肽1(CATH1)、鸡源Cathelicidins抗菌肽2(CATH2)、鸡源Cathelicidins抗菌肽3(CATH3)、禽β-防御素1(AvBD1)、禽β-防御素4(AvBD4)和禽β-防御素7(AvBD7)的mRNA相对表达量(P<0.05)。5)与对照组相比,饲粮中添加30和60 mg/kg 5-ALA显著提高回肠绒毛高度/隐窝深度比值(V/C)(P<0.05);且随饲粮中5-ALA添加水平的增加,42日龄肉鸡十二指肠绒毛高度呈线性升高趋势(P<0.05)。综上所述,饲粮中添加适宜水平的5-ALA能促进肉鸡HGB的形成,提高肉鸡的免疫功能,改善肠道形态结构。在本试验条件下,肉鸡饲粮中5-ALA的适宜添加水平为45~60 mg/kg。

This study aimed to investigate the effects of dietary supplementation with 5-aminolevulinic acid(5-ALA)on growth performance,blood routine indices,immune function and intestinal morphology in broilers.A total of 300 one-day-old Arbor Acres broilers were distributed into 5 groups with 6 replicates of 10 broilers by a completely randomized design.The broilers in the 5 groups were fed the basal diet with 0(control),15,30,45,and 60 mg/kg 5-ALA,respectively.The results showed as follows:1)dietary 5-ALA supplementation had no significant effects on average daily feed intake(ADFI)and average daily gain(ADG).Dietary supplementation with 60 mg/kg 5-ALA reduced the feed to gain ratio(F/G)during 1 to 21 days of age and 22 to 42 days of age(P<0.05).Moreover,with the dietary 5-ALA supplemental level increased,the F/G was linearly decreased(P<0.05).2)Dietary supplementation with 30,45 and 60 mg/kg 5-ALA increased the blood hemoglobin(HGB)content of broilers on 21 days of age.At the same time,with the increase of 5-ALA supplemental level,the HGB content and red blood cell counts(RBC)were linearly increased(P<0.05).3)Dietary supplementation with 45 mg/kg 5-ALA increased the contents of immunoglobulin M(IgM)and immunoglobulin G(IgG)in serum of broilers on 21 days of age(P<0.05),and dietary supplementation with 30 or 45 mg/kg 5-ALA increased the contents of IgM,IgG and immunoglobulin A(IgA)in serum of broilers on 42 days of age(P<0.05).Moreover,dietary supplementation with 45 and 60 mg/kg 5-ALA improved the contents of complement 3(C3),complement 4(C4),and interferon-γ(INF-γ)in serum of broilers on 21 days of age.And the C3 and C4 contents in serum of broilers on 21 days of age were linearly increased(P<0.05).4)Compared with the control group,the mRNA relative expression levels of Avianβ-defensin(AvBD)1,AvBD2,AvBD7 and Cathelicidin(CATH)1,CATH2,CATH3 in liver were upregulated in 5-ALA supplementation group(P<0.05).5)Dietary supplementation with 30 and 60 mg/kg 5-ALA increased the ileal villus height/crypt depth ratio(V/C)of broilers on 42 days of age.Moreover,with the dietary 5-ALA supplemental level increased,the villous height of duodenum was linearly increased(P<0.05).In conclusion,dietary supplementation with 5-ALA promotes the formation of hemoglobin,improves the growth performance,immune function and intestinal mucosal morphology of broilers,and the appropriate supplemental level is 45 to 60 mg/kg.