Preparation Of Peptide Yy Complete Antigen And Nutritional And Physiological Effects Of Passive Immunization Against Peptide Yy In Rats

In this study, we used the coupled compound of peptide yy(PYY) and carrier protein(bovine serum albumin,BSA) as antigen to antive immunize rabbits,aimed to prepare PYY serum antibodies.Then,we passive immunized rats with PYY anti-serum in order to research the effection of PYY on rats growth performance,serum hormone levels and digestive enzymes by passive immunization to consume endogenous PYY.The PYY was coupled to BSA as an immunogen antigen using the coupling agent EDC and we detected the complete antigen by SDS-polyacrylamide gel electrophoresis if PYY and BSA was successfully coupled.We selected three healthy male rabbits and randomly chose two rabbits as test rabbits.The two test rabbits was immunized of PYY-BSA complete antigen.The immunization procedure included one initial injection(200μl/rabbit) and seven boosters(200μl/rabbit).Primary inoculation was on day 1 and booster inoculations were on day 8,18,……,58.After each booster immunization,we determined the antibody with enzyme linked immunosorbent assay.60 SD rats with body weight of 87.77±1.61g were distributed randomly into 4 treatments with 5 peplicates of 3 rats.The control group was injected nothing.Three experimental groups were injected PYY antibody 50μl/rabbit,100μl/rabbit,200μl/rabbit respectively.We injected PYY antibody three times in every 7 days.Rats were fed freely during the whole test.After the test,pancreas,duodenum and gastric were rapidly removed,and blood anmples were collected in centrifuge tubes of 10ml.We detected the content of PYY,insulin,leptin,gastrin and neuropeptide Y(NPY),we also detected the specific activity of amylase and lipase in pancreas and duodenum and pepsin activity.The results showed, (1).According to the electophoresis result,PYY was successfully coupled with BSA,and PYY-BSA molecular weight greater than the molcular weight of BSA.(2).According to ELISA testing showed, PYY antibody in serum was postive after sixth immunization, and suggesting that there was PYY antibody in rabbit in vivo.(3).lnjection of different doses of PYY antibody on average body weight of rat.In 0-7 days,the average bodyweight was not significantly difference (P>0.05) of control group and treatment gpoups.In 8-14 days,there was significantly difference (P<0.05) in control group and experiment groups.In 15-21 days,the average bodyweight of experiment groups was significantly higher (P<0.05) than control group.(4).Injection of different doses of PYY antibody on average daily feed intake(ADFI) of rats.In 0-7 days,8-14 days and 15-21 days,the ADFI was aways significantly difference (P<0.05) in control and experiment groups.At different stage,feed/gain(F/G) was reduced and there was no significant difference (P>0.05) in control group and experiment groups.(5).Injection of different doses of PYY antibody on nutrients metabolic rate of rats.For the utilization of dry matter,there was no significantly difference (P>0.05) in control group and experiment groups.The utilization of dry matter of control was highest than experiment groups'.The utilization of crude protein and energy of three experiment groups was significantly higher (P<0.05) than control group.(6).With the increased of PYY antibody,the concent of NPY,leptin,gastrin and insulin in serum also increased,but there was no significantly difference (P>0.05) in control and experiment groups. With the increased of PYY antibody,the concent of PYY in serum induced,and there was no significantly difference in control and experiment groups.(7).With the increased of PYY antibody,the specific activity of pancreatic lipase and pancreatic amylase increased.There was no significantly difference (P>0.05) of specific activity of pancreatic lipase in control and experiment groups.The specific activity of pancreatic amylase of third experiment was significantly highest (P<0.05) than other groups.(8).With the increased of PYY antibody, the specific activity of duodenal lipase and duodenal amylase increased.The specific activity of duodenal lipase of second and third experiment group were significantly higher (P<0.05) than control and first experiment group.There was no significantly difference (P>0.05) of duodenal amylase of control and experiment groups,the specific activity of duodenal amylase of third experiment was highest.(9).With the increased of PYY antibody, the specific activity of pepsin decreased.There was no significantly difference of control and experiment groups. These results suggest that injection of PYY antibody could improve growth performance of rats through decreasing the content of PYY in serum to weaken the biological effects by raising the antibody tite of PYY.