Acrylamide Production in Autoclaved Rodent Feed

Dry Heat Sterilization of a Pelleted, Natural Ingredient Rodent Diet

Sterilization of rodent feed is recommended to eliminate potential murine pathogens and minimize microbial variability between batches. Most research institutions sterilize feed using steam/pressure (autoclave) or irradiation. Both methods have advantages and disadvantages that contribute to their suitability, including cost, maintenance, availability, and alterations to the exposed product. Dry heat sterilization, which has been in use for over 75 y, uses higher temperatures and longer sterilization times than steam autoclave and is most often used for delicate instruments or products that would be damaged by water such as powders or oil-based liquids. Dry heat sterilization in vivaria has been limited to date but is gaining popularity due to lower initial purchase and ongoing operational costs as compared with steam autoclaves. Little published information exists on the effects of dry heat sterilization on animal feed. We evaluated the sterility and chemical alterations of a natural ingredient, pelleted, rodent diet (NIH-31) after exposure to dry heat. Feed sterility was achieved using a dry heat exposure temperature of 160 °C (320 °F) for 4 h. This exposure resulted in a significant loss of heat-labile vitamins and significantly more acrylamide production as compared with the nonsterile, irradiated, and autoclaved feed.

Risk of exposure to acrylamide

OBJECTIVES

Acrylamide is a toxic compound that can be found it both occupational and non-occupational environments. This study focuses on its sources and health effects of its exposure.

METHODS

Adverse effects of acrylamide, especially carcinogenic, genotoxic, and teratogenic were reported in many studies conducted on animals. Neurotoxicity was reported in workers exposed to acrylamide in the occupational environment. Another important source of populations' exposure to acrylamide is their nutrition.

RESULTS

This study focuses on humans' exposure to acrylamide from various sources and its harmful effects on their health.

CONCLUSIONS

Dietary intake of acrylamide, as well as occupational exposure, cigarette smoking, cosmetics usage and other environmental sources could have a significant effect on human health.

The Influence of Feed and Drinking Water on Terrestrial Animal Research and Study Replicability

For more than 50 years, the research community has made strides to better determine the nutrient requirements for many common laboratory animal species. This work has resulted in high-quality animal feeds that can optimize growth, maintenance, and reproduction in most species. We have a much better understanding of the role that individual nutrients play in physiological responses. Today, diet is often considered as an independent variable in experimental design, and specialized diet formulations for experimental purposes are widely used. In contrast, drinking water provided to laboratory animals has rarely been a consideration in experimental design except in studies of specific water-borne microbial or chemical contaminants. As we advance in the precision of scientific measurements, we are constantly discovering previously unrecognized sources of experimental variability. This is the nature of science. However, science is suffering from a lack of experimental reproducibility or replicability that undermines public trust. The issue of reproducibility/replicability is especially sensitive when laboratory animals are involved since we have the ethical responsibility to assure that laboratory animals are used wisely. One way to reduce problems with reproducibility/replicability is to have a strong understanding of potential sources of inherent variability in the system under study and to provide "…a clear, specific, and complete description of how the reported results were reached [1]." A primary intent of this review is to provide the reader with a high-level overview of some basic elements of laboratory animal nutrition, methods used in the manufacturing of feeds, sources of drinking water, and general methods of water purification. The goal is to provide background on contemporary issues regarding how diet and drinking water might serve as a source of extrinsic variability that can impact animal health, study design, and experimental outcomes and provide suggestions on how to mitigate these effects.

All You Can Feed: Some Comments on Production of Mouse Diets Used in Biomedical Research with Special Emphasis on Non-Alcoholic Fatty Liver Disease Research

The laboratory mouse is the most common used mammalian research model in biomedical research. Usually these animals are maintained in germ-free, gnotobiotic, or specific-pathogen-free facilities. In these facilities, skilled staff takes care of the animals and scientists usually don’t pay much attention about the formulation and quality of diets the animals receive during normal breeding and keeping. However, mice have specific nutritional requirements that must be met to guarantee their potential to grow, reproduce and to respond to pathogens or diverse environmental stress situations evoked by handling and experimental interventions. Nowadays, mouse diets for research purposes are commercially manufactured in an industrial process, in which the safety of food products is addressed through the analysis and control of all biological and chemical materials used for the different diet formulations. Similar to human food, mouse diets must be prepared under good sanitary conditions and truthfully labeled to provide information of all ingredients. This is mandatory to guarantee reproducibility of animal studies. In this review, we summarize some information on mice research diets and general aspects of mouse nutrition including nutrient requirements of mice, leading manufacturers of diets, origin of nutrient compounds, and processing of feedstuffs for mice including dietary coloring, autoclaving and irradiation. Furthermore, we provide some critical views on the potential pitfalls that might result from faulty comparisons of grain-based diets with purified diets in the research data production resulting from confounding nutritional factors.