Screening Of Synbiotics And Their Effects On The Growth Performance Of Broilers

In order to offset disadvantage of low vitality rate and weak colonization capacity in theusage of probiotics, this research takes advantage of the seven lactic acid bacteria (LAB)separated from broilers by our lab combining with oligosaccharides and screen the selectivestimulating effects. Its role in synbiotics is also tested by in vitro inhibition tests andexperiments on animals. To fully make use of the rich resources of Chinese traditionalmedicine, this research uses the Pericarpium cirri extract and Radix Astragali extract based onthe fundamental theories on Chinese traditional medicine and develop Chinese synbiotics byusing three LAB strains D2, D17 and K9 by the in vivo and in vitro experiments to get goodeffects. The experiment includes five sections:In the first section, in order to screen the combinations with selective stimulated effect,the synbiotic effects between oligosaccharides including inulin, fructo-oligosaccharides(FOS), xylo-oligosaccharides (XOS), isomaltaoligosaccharides(IMO) and lactic acid bacteria(LAB) from broiler were tested by in vitro fermentation. Then the growth and the variationof lactic acid concentration of LAB strains (D2,D17,K9)combined with different prebioticswas investigated. The results showed that the selective stimulation effect existed betweenLAB and oligosaccharides, different LAB species has different degradation capability onoligosaccharides, even the same LAB species except for subspecies. In this study,D2,D17,K9 can degrade most of oligosaccharides, moreover different mixture ofoligosaccharides (Inulin+FOS and FOS+XOS) can enhance the growth as well as increasethe lactic acid production of LAB.In the second section, the effects of lactic acid bacteria strains (D2,D17,K9)combinedwith different mixtures of prebiotics (Inulin+FOS and FOS+XOS) on intestinal pathogenswere investigated. Lactic acid bacteria LAB grown with different prebiotics were observed toinhibit the growth of Escherichia coli and Salmonella pullorum significantly. The extent ofinhibition varied according to the strains and the Strain K9 had the best inhibitory effect. Theeffect of LAB grown with FOS+XOS was greater than theirs with Inulin+FOS. The resultindicated that in order to produce better inhibitory effect by probiotics, attention shoud bepaid to the combinations of probiotics and substrate in addition to the selective stimulation ofthem and prebiotics. In the third section, A crude preparation of live probiotics A (D2+D17+K9) andsynbiotics were created to investigate their effects on the growth performance of broilerswith corn-based diet. 810 broilers at age of zero were randomly divided into nine groups.The group with no antibiotics in the diet was served as control 1, the group with antibioticsin the diet was served as control 2. Group A was supplemented with probiotics A(D2+D17+K9) based on control 1. Group B was supplemented with probiotics A andprebiotics A (FOS+XOS) based on control 1. Group C was supplemented with probiotics Abased on control 2. Group D was supplemented with probiotics A and prebiotics A (FOS+XOS) based on control 2. Group E was supplemented with probiotics A and prebiotics B(FOS+Inulin) based on control 2. Group F was supplemented with prebiotics A (FOS+XOS) based on control 2. Group G was supplemented with prebiotics B (FOS+Inulin)based on control 2. Preliminary results showed that during the age of 1to 21, weight gain ofgroup A (probiotics A) was much lower than that of control 1(P＜0.05), but similar to thatof the control 2(P＞0.05). Weight gains of group B (no antibiotics+probiotics A+prebioticsA (FOS+XOS)) was similar to those of the control 1 and 2. The results of the ratio of feedto weight gain (F/G) showed that F/G of group B (no antibiotics+probiotics A+prebioticsA (FOS+XOS)) was much lower than that of control 2(P＜0.05), similar to that of thecontrol 1. Compared with control 2, F/G of group D (antibiotics+probiotics A+prebioticsA (FOS+XOS)) was significantly lower. During the age of 22 to 42, F/G of Group C (noantibiotics+probiotics A), Group D (no antibiotics+probiotics A+prebiotics A (FOS+XOS)) were significantly lower than that of control 2(P＜0.05). During the age of 1 to 42,only F/G of Group D (no antibiotics+probiotics A+prebiotics A (FOS+XOS)) wassignificantly lower than that of control 2(P＜0.05). The results of diarrhea rate showed thatdiarrhea rates of Group C (no antibiotics+probiotics A) and G (no antibiotics+prebioticsB (FOS+Inulin)) were lower than that of control 2(P＞0.05), Group D (no antibiotics+probiotics A+prebiotics A (FOS+XOS)) was significantly lower (P＜0.05).In the fourth section, extracts from Pericarpium citri and Radix Astragali at differentdoses (0%,0.5%,1.0%) were screened for their effect on the growth of lactic acid bacteria(LAB)(D2,D17,K9) in basal medium. The results showed that without substrate in basalmedium, the number of LAB would decrease according to the time, the pH value and thelactic acid production were quite low. Each LAB can grow well by degrading 0.5% or 1.0%Pericarpium citri in basal medium while produce lactic acid. Each LAB also can grow wellby degrading 0.5% or 1.0% Radix Astragali in basal medium but only D17 and K9 produce lactic acid except D2.In the fifth section, A crude preparation of live LAB (probiotics A (D2+D17+K9))and Chinese herb extracts and Chinese herb synbiotics were created to investigate theireffects on the growth performance of broilers with corn-based diet. 630 broilers at age ofzero were randomly divided into seven groups. The group with no antibiotics in the dietwas served as control 1, with antibiotics served as control 2. Group A was supplementedwith probiotics A (D2+D17+K9) based on control 1. Group B was supplemented withPericarpium citri extract based on control 1. Group C was supplemented with RadixAstragali extract based on control 1. Group D was supplemented with probiotics A andPericarpium citri extract based on control1. Group E was supplemented with probiotics Aand Radix Astragali extract based on control1.Preliminary results showed that during theage of 1to 21, compared with control 1, the results of the ratio of feed to weight gain (F/G)showed that F/G of group C (no antibiotics+Radix Astragali extract) was significantlylower than that of control 1 (P＜0.05), the others' were similar to that of control 1. F/G ofgroup A, B, C, D and E were similar to that of control 2 (P＞0.05). During the age of 22 to42, compared with control 1 and 2, the probiotics A, Pericarpium citri extract and RadixAstragali extract and their combinations had no significant effects on broilers' daily weightgain (P＞0.05); the daily weight gain of Group D (no antibiotics+probiotics A+Pericarpium citri extract)was increased by 7.37％and 5.85％compared with control1 and2 separately. F/G of Group group A,B,C,D and E was significantly lower than that ofcontrol 1 (P＜0.05). Only the F/G of group C (no antibiotics+Radix Astragali extract) wassignificantly lower than that of control 2 (P＜0.05).During the age of 1 to 42, F/G of GroupA, B, C, D and E were significantly lower than that of control1 (P＜0.05), F/G of group B(no antibiotics+Pericarpium citri extract),group C (no antibiotics+Radix Astragaliextract) and group E (no antibiotics+probiotics A+Radix Astragali extract) weresignificantly lower than that of control 2(P＜0.05).