Study On Solid-phase Synthesis Of Immunity Active Peptide And Its Application In Reducing SCC In Dairy Cow

Somatic cell count (SCC) is the total number of Somatic cell per milliliter milk. Its main component is white blood cell which is about 99%, and the rest is bovine mammary epithelial cell. The amount of SCC directly reflects the health status of dairy cows, and has extensive and complicated influence on milk component and dairy products. Those years investigator pay more and more attention on controlling of SCC and to find the products which can improve the constitution of the dairy cows along with the increasingly desire of people to high milk quality.The Immunity Active Peptide(IAP) in this thesis is sieved by the bank of peptide which function is improving cell metabolism, reducing harmful toxins and strengthening resistance and anti-stress. Its clinic characterization is effectively reduing SCC, increasing and steadying milk yield and improving milk quality and flavor. All those characters make it had very broad market prospects. The objective of this thesis is to find an optimized solid-phase peptide synthesis method which is a feasible way to reduce cost and for amplify.In this experimentation, the LAP was synthesized by Solid-Phase method. This method utilized Fmoc-amino acid as the raw material and Wang resin as solid supporter. And studied the synthesis technics on protection of amino acid, coupling reagent, deblocking strategy and cleavage reagents. We blocked the remains active sites of the resin and the amino acids which were difficult to couple to increase the coupling efficiency. The crude peptide was identified by MALDI-MS TOF that had the same molecular weight with the theoretical one, and separated and purified by RP-HPLC. Finally we established the integral technics and the parameters of synthesis and purification of LAP. And then we attempted to make batch production. After this, we fed the LAP to dairy cows and analysed the influence of IAP to SCC, milk yield and milk components.Under the optimized conditions, the yield of crude peptide was 91.56%, and the purity was 80.02%. The purity of IAP was more than 98% after purified and the yield of purification was 7.645%. The results demonstrated that this synthesis-separation method is simple, convenient and has short cycle and low cost. The yield of purified peptide of Batch production that the amount of resin was amplified with ten times was 9.49g which can satisfy the demand. The feeding experiment showed that the dairy cows' immunity was obviously strengthened and the SCC was reduced below 50 ten thousands per milliliter after fed the IAP, the milk yield was increased about 1.15kg everyday, milk fat percentage and milk protein percentage all increased.