Cholecystokinin Active Immunization And Its Immunization On The Growth Performance And Carcass Quality Of Pigs

Cholesystokinin (CCK) is a regulator of feed intake, and cholecystokinin will suppress feed intake of animals. Feed intake can be raised by CCK active immunization neutralizing endogenous cholecystokinin. For establishing a sound technique of active immunization against CCK-8, CCK-8 (the C-terminal octapeptide of cholecystokinin ) was conjugated to human serum albumin(HSA) by glutaraldehyde condensation.Then for verifying the antigenicity of antigen, eight rabbits were randomly assigned two treatments with 4 replicates. The treated group was immunized with the C-terminal octapeptide of cholecystokinin conjugated to human serum albumin(HSA), the control group was immunized with human serum albumin(HSA) by the same protocol. Serum titers of antibodies were estimated from double diffusion in two dimension. The results showed that the antibody titers of all treated rabbits were 1:24 (1:16) after 3 booster immunizations. In the same time, the result also showed that the technique of active immunization against CCK-8 was successful in this experiment.The another experiment was conducted to investigate the effect of CCK active immunization on growth performance, carcass quality, meat quality and nutrient digetibilties in pigs . Ten pigs were randomly assigned in two treatments with 5 replicates. The treated group was immunized with the C-terminal octapeptide of cholecystokinin conjugated to human serum albumin(HSA), the control group was immunized with human serum albumin(HSA) by the same protocol. Serum titers of antibodies were estimated from enzyme linked immunosorbent assay(ELISA). The nutrient digetibilties were estimated from the method of exogenous indicator.Carcass length, Lion- eye area, color of meat, marbling score, pH value, drip loss and fat:protein rations of pigs were detected after pigs were slaughtered. The results showed that the antibodies could be examined 15 days afer primary immunization and active immunization againstCCK-8 resulted in development of high antibody titers against CCK-8 after 3 booster immunizations. Total average daily feed intake (ADFI) during the 77-day study was 16.24% greater for the CCK-8 grou p(p=0.152); average daily weight gain (ADG) was21.23% greater(p=0.104); F/G(feed/gain) was 4.86% lower(p=0.138). Regression analyses confirmed that the regression equation between ADFI and antibody titers was: (y=408.684+2165.87x, R2=0.768, p=0.051), and the regression equation between weight and antibody titers was: (y= -7.359+87.16x R2=0.956, p=0.004). In the same time, the final weight was 12.68% greater for the CCK-8 group (p =0.178) .There were no significant difference in pigs carcass length, thickness of back, lion- eye area. Active immunization against CCK-8 had no effect on color of meat, marbling score, pH value, drip loss and fat:protetn rations. The result showed that growth performance could be improved of pigs by active immunization against CCK-8 But active immunization against CCK-8 had no effect on carcass quality and meat quality.