بررسي مقايسه اي تاثير مواد شيميايي و تخمير طبيعي بر روي كيفيت ميكروبي و آنتي بادي IgG آغوز گاو به منظور افزايش ماندگاري آن

Comparative survey of the effects of chemical preservatives and natural fermentation on microbial quality and IgG antibodies in order to increase shelf life of bovine colostrum.

زمينه مطالعه: آغوز گاوي اولين شير ترشح شده پس از تولد گوساله مي باشد و ماده‌اي بسيار مغذي سرشار از فاكتورهاي ايمني-بخش، فاكتورهاي رشد و ترميم بافت و فاكتورهاي ميكروبي مي‌باشد. آلودگي ميكروبي آغوز موجب تداخل در جذب آنتي‌بادي‌هاي موجود در آغوز مي‌شود. هدف: بررسي اثر نگهدارنده هاي شيميايي و تخمير طبيعي جهت ذخيره سازي آغوز به منظور حفظ كيفيت آن مي باشد. روش كار: براي انجام اين تحقيق آغوز حاصل از شيردوشي اوليه بعد از زايمان، از 5 گاو نژاد هلشتاين به‌طور مجزا جمع‌آوري شد. نمونه‌ها فوراً به آزمايشگاه منتقل شدند و آزمايشات ميكروبي بر روي نمونه‌هاي آغوز تازه انجام شد. سپس نمونه‌هاي آغوز بعد از انجام تيمار با اسيد پروپيونيك، اسيد فرميك و سوربات پتاسيم و روش تخمير طبيعي در روزهاي1،10،20،30 ذخيره سازي از نظر باكتري‌هاي شاخص شامل بارميكروبي‌كل و اشرشيا كلي، كلي‌فرم ،كپك ومخمر، مورد ارزيابي قرار گرفتند. سپس در پايان روز 30 از نمونه هاي تيمارشده wheyتهيه شد و آزمون SRID به‌منظور سنجش آنتي‌بادي IgG در نمونه شاهد و نمونه هاي تيمار شده انجام شد. نتايج: سوربات پتاسيم نقشي در كاهش باكتري‌هاي اشرشيا كلي و كلي فرم نداشت اما مانع افزايش تعداد آنها در طي 30 روز شده است. اسيد فرميك و اسيد پروپيونيك موجب كاهش باكتري اشرشياكلي و كلي فرم (0/05>P) شدند. همچنين اين دو اسيد موجب رشد بيش از حد كپك و مخمر در مقايسه با سوربات پتاسيم شدند. اما سه تيمار ياد شده نقشي در كاهش بارميكروبي كل (0/05

BACKGROUND: Colostrum is the first milk produced after birth and is particularly rich in immunoglobulins, growth factors and antimicrobial peptides. Therefore, maintenance and storage of bovine colostrum has always been considered due to benefits of colostrum for the calf. Microbial contamination of colostrum is a concern because it is thought that bacteria in colostrum may interfere with passive absorption of colostral antibodies. OBJECTIVES: The aim of this study was to evaluate the effects of chemical preservatives and natural fermentation on quality and storage of colostrum. METHODS: Colostrum from the first milking of five Holstein cows was stored separately. Then colostrum samples were studied at days 1, 10, 20, and 30 of storage after treatment. All samples underwent microbiological culture for total plate count and detection of Escherichia coli, Coliforms, mold and yeast. Then whey was provided from untreated and treated samples at the end of 30th day and SRID (single radial immune diffusion) test was performed for assaying IgG antibody. Then the effect of treatments on colostrum antibody level was studied. RESULTS: The results showed that potassium sorbate did not have a role in reducing E.coli and coliforms count. However, it has prevented an increase in E.coli and coliform count during 30 days. Formic acid and propionic acid reduced the number of E. coli and coliform (p<0.05). In addition, the two organic acids promoted the growth of mold and yeasts compared with potassium sorbate. Nonetheless, the mentioned three treatments did not have an important role in reducing total count (p>0.05). The natural fermentation contributed to the decline of E. coli and coliform count while total count increased one day after treatment compared with other treatments, however among the treatments, formic acid and potassium sorbate were more effective than propionic acid and natural fermentation treatment for maintaining hygienic quality of colostrum. The result of measuring IgG antibody indicated that potassium sorbate has had more protective effect than other treatments. CONCLUSIONS: The results exposed that potassium sorbate and formic acid are better than other treatments to maintain colostrum quality with regard to increasing shelf life of colostrum.