Effects Of Pericarpium Citri Reticulatae Alone Or In Combination With Lactic Acid Bacteria On Growth Performance And Microflora In Ileum And Caecum And Serum Antioxidant Activity Of Broilers

The use of subtherapeutic antibiotics has been a cornerstone of the poultry for decades, synbiotics present a promising alternative. The present study was conducted to evaluate the effect of combined Pericarpium Citri Reticulatae with three lacticacid bacteria (LAB) isolated from broilers in our lab on the growth performance, microflora changes in ileum and caecum of broilers, and the antioxidant activity. The whole experiment was divided into four sections.In the first section, extracts from Pericarpium Citri Reticulatae at different doses (0%、0.5%、1.0%) were screened for their effect on the growth of lactic acid bacteria(LAB)(C1、 D17、K9) in basal medium. The results showed that without substrate in basal medium, the number of lactic acid bacteria increased slowly according to the time, the pH value and the lactic acid production were quite low. The multiplication of each lactic acid bacteria in0.5%or1.0%Pericarpium Citri Reticulatae extract groups cultured in MRS medium was increased rapidly with time, which had significant difference(P<0.05) compared with the basal medium; The pH values in three strains of C1、K9and D17culture showed the fast decline during24hours, with the final values lower than those of the basal mediums; The results of lactic acid production showed that among all strains K9exhibited the highest production (P<0.05) of lactic acid by12and24hours.In the second section, the effects of Pericarpium Citri Reticulatae alone or in combination with LAB on growth performance of broilers were investigated.720broilers at the age of1d were selected and randomly allocated into eight treatments with5replicates of18broilers in each treatment. Control1and2were fed basal diets without or with antibiotics; treatment A, B and C were fed basal diets supplementing with Pericarpium Citri Reticulatae at levels of0.1%,0.2%or0.4%respectively; treatment D、E and F were fed basal diets supplementing with LAB and Pericarpium Citri Reticulatae at levels of0.1%,0.2%or0.4%respectively. The results showed that supplemental Pericarpium Citri Reticulatae of0.2%could improve growth performance during1-21d, and better promotion of the role of Pericarpium Citri Reticulatae of0.2%and LAB. But this effect was not obviously during22-42d and1-42d.In the third section, the effects of Pericarpium Citri Reticulatae alone or in combination with LAB on LAB and Enterobacteria in ileum and caecum of broilers were investigated. The experiment design was the same as experiment2. The results showed that at the age of21days, except treatment A,the number of caecal LAB of treatments added Pericarpium Citri Reticulatae alone and in combination with LAB was larger than that of control1and2(P<0.05). At the same age, the ratio of LAB to Enterobacteria in ileum and caecum of all treatments were higher than that of two controls, and the ratio of treatment C、E、F was significant higher than that of control1(P<0.05); but this effect was not obviously at the age of42days. The results indicated that Pericarpium Citri Reticulatae alone and in combination with LAB could stimulate the number of caecal LAB and enhance the ratio of LAB to Enterobacteria in ileum and caecum of broilers when they were at the age of1-21days.In the fourth section, the effects of Pericarpium Citri Reticulatae alone or in combination with LAB on antioxidant activity of broilers were investigated. The experiment design was the same as experiment2. At d21and d42, the activites of SOD, GSH-Px and T-AOC and levels of MDA in serum were measured. At the age of21days, Compared with control group, supplemental Pericarpium Citri Reticulatae of0.1%alone and in combination with LAB could both enhanced the activities of GSH-Px in serum (P<0.05), meanwhile, compared with control1, SOD activity and T-AOC of treatment E (supplemental Pericarpium Citri Reticulatae of0.2%and in combination with LAB) had increased by57.98%and38.09%respectively, but had no significant difference (P>0.05); serum MDA concentration of treatment D, E、F were decreased at21d(P>0.05), contrasted to the control1. At the age of42days, GSH-Px activity of treatment A、F in serum decreased significantly(P<0.05), while there were no significant differences in SOD、MDA and T-AOC of blood serum(P>0.05).