Study On The Sterilizing Effects On The Fodder With Co～(60) Irradiaion And It's Apllication In SPF Chickens

The irradiation has been generally adopted to sterilize fodder for specific pathogen-free (SPF) chickens overseas since 1970s. The advantage of irradiating-sterilization is that no thermo-exchange happened in the process. In China, the fodder is usually sterilized by autoclave, which resulted considerable loss of main nutrition compositions and vitamins. Because of high cost, lack of security requirement and Co⁶⁰,irradiation hasn't be used to sterilize fodder in China until nowadays. In foreign countries, Co⁶⁰ was adopted to sterilize the fodder at a dose of 25KGY. However, there were still no standard dose of Co⁶⁰ sterilizing fodder and its application in SPF chickens at present in China. In present study, we sterilized fodder for SPF chickens in different dose of Co⁶⁰, and the quality guarantee period of the fodder sterilized was determined. Then we compared the effect on the fodder sterilized by autoclave (121℃) and irradiation of Co⁶⁰ (25KGY).Fodder for SPF chickens had been divided into eight different groups, which were irradiated by Co⁶⁰ at dose of 5, 10, 15, 20, 25, 30, 35 and 40KGY respectively. In contrast, another fodder was sterilized by autoclave. Bacteriological examination and the measurement of the major nutritious components and vitamin were carried on in 7, 30, 60, 90 and 120 days post sterilization. The major nutritious components included water, crude protein, crude fat, crude fiber, crude ash. Vitamin included vitamin A, B1, B2, B6, VB6, VD, VE and VK. Consequently, We determined the dose of Co⁶⁰ sterilizing fodder and the quality guarantee period of the fodder sterilized by it. We also compared the fodder sterilized by autoclave (121℃) and Co⁶⁰ (25KGY). The results are as followed:i. The fodder irradiated by Co⁶⁰ at dose of 20, 25, 30, 35 and 40 KGY was all germfree to feed SPF chickens. The fodder in dose of 25KGY keep sterile for 120 days at room temperature, while the fodder in dose of 20KGY just keep sterile for 60 days. In the fodder irradiated by different dose of Co⁶⁰, the percentage of water, crude protein, crude fiber and crude ash showed no significant difference. With the dose of Co⁶⁰ increasing, the percentage of crude fat got more, while the percentage of vitamin decline, especially Vitamin A and vitamin B. In the fodder in dose 40 KGY, the percentage of vitamin A just remained 82.3%, and the vitamin B, 82.8%. In a conclusion, 25KGY was the most useful sterilizing dose.