Effect of Gamma Irradiation on Microbial Decontamination, Crude Nutrient Content, and Mineral Nutrient Composition of Laboratory Animal Diets


G. Shahhosseini 1 , A. Karimi 2 , * , S. Amanpour 3 , M. A. Mansouri 4


1 Nuclear Agriculture Research School, Nuclear Science and Technology Research Institute, Karaj, Iran.

2 Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.

3 Cancer Biology Research Center, Tehran University of Medical Sciences, Tehran, Iran

4 Department of Research, Breeding and Production of Laboratory Animals, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization, Karaj, Iran


Archives of Razi Institute: 74 (2); 175-182
Published Online: June 01, 2019
Article Type: Journal Article
Received: November 03, 2017
Accepted: December 18, 2017




Laboratory animal models are an important part of test design. Certain conditions such as microbial contamination in diets of these models could affect the results of experiments. One of the most important routes that predispose to contamination is generated through feeding of laboratory animals. This study aimed to show the effect of gamma irradiation in reducing bacteria concentrations, crude nutrient content, and concentrations of some minerals and trace elements in laboratory animal diets. Large-sized pellets with 10–15 mm diameter (commonly used for rats and hamsters) and small-sized pellets with 3–5 mm diameter (used for rabbits and guinea pigs) along with skimmed milk powder (SMP) as a food additive were exposed to gamma irradiation with different doses ranging from 3 to 30 kGy. The total microbial contamination and any possible changes in some mineral nutrient composition and the crude nutrient content were determined pre- and post-irradiation. Our data revealed that 25 kGy in pelleted diets and 18 kGy in SKM had superior effects in the reduction of bacterial contamination with little change in crude nutrient content and minerals and trace elements in nutrient requirements of laboratory animals. According to the results, gamma irradiation had minimal effects on crude nutrient content and the concentrations of some minerals and trace elements of laboratory animal diets, and it also eliminated bacterial and fungal contamination load. By using gamma irradiation, this method could yield a favorable outcome in controlling microbial contamination of animal diets.


Gamma Irradiation Laboratory animal Diet Bacteria Pellet

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