UNIVERSITY OF ARKANSAS MEDICAL CENTER

Research Projects: Prolonged Toxicity Testing and Animal Odor Control

Evaluation of an Enzymatic Animal Food Additive

Principal Investigator: H. E. Farris, D.V.M.

Division of Laboratory animal Medicine

University of Arkansas Medical Center

Discussion:

   The absence of signs of toxicity during the 90-day study indicates "MSE" is a safe feed additive for dogs. Other studies in our laboratory have confirmed the safety of "MSE". Fifteen mice were fed a 100% diet of "MSE" for 90 days. At the end of the 90 day period a complete pathologic examination was performed on each animal. There were no pathological changes in the mice. During the study they remained healthy and although their bedding was changed only at 2-week intervals there was no odor.

   In this study "MSE" reduced the fecal odor significantly below the fecal odor of dogs fed only dog chow. However, unlike the results obtained in the mouse study, where fecal odor could not be detected, a moderate dog odor was noted by the odor panel.

   Perhaps dog odors other than fecal odor accounted for the moderate odor in the rooms containing the dogs fed "MSE". In addition, there were 8 dogs per room. At this density odors other than fecal i.e., urine could have moderate levels of odor.

   Twice the recommended dosage of "MSE" was the largest amount fed in this study. I would suggest that because of the excellent results obtained with mice fed only an "MSE" ration that a higher dosage of "MSE" be used in a series of household studies.

   The present trend of feeding mixtures of products produced from cultures of Aspergillus oryzae and vitamin-minerals to cattle for growth promoting purposes might have application in the pet food industry. Specifically, a mixture of "MSE", vitamins and minerals would have appeal as a feed additive.

Summary:

   A 90-day toxicity study in mice and dogs demonstrated the safety of "MSE" as a feed additive. Fecal odor was eliminated in mice fed only "MSE". Dogs fed from .001 to .002 percent of their diet had less fecal odor, but a moderate odor was still present as determined by a 10 member odor panel.

   The potential of an appropriate mixture of "MSE", vitamins and minerals as a diet supplement would appear to be nutritionally sound and as based on this study should reduce fecal odor.

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A 90-DAY ODOR EVALUATION AND TOXICITY TEST OF MSE

Introduction:

   The purpose of this study was twofold, (1) evaluate fecal odor reducing properties of "MSE" and (2) evaluate the overall effect of "MSE" on the digestive system, biochemical measurements and weight.

Materials and Methods:

   Twenty four dogs were randomly assigned to 3 animal rooms. One room was randomly selected as the control (regular dog chow), a second as test group I (manufacturer's recommended amount of "MSE") and the third group recieved a double amount of "MSE".

   All animals within a room were individually housed and observed daily for signs of toxicity (attachment 1). Animals were weighed and temperatured twice weekly. Blood samples for complete hematologic and a biochemical profile were obtained every 4 weeks.

   Odor was evaluated by a 10 member odor panel randomly selected from the school of pharmacy student body. Panel members were individually escorted to the three test rooms, blindfolded and led into each room. After entering each room and remaining for 2 minutes, the three rooms were evaluated as follows:

0 - no odor

1 - slight odor

2 - moderate odor

3 - strong odor

   In addition, the three rooms were ranked 1 - 2 - 3 with the most odiferous room ranked first and least odiferous ranked 3.

Stool samples were examined and cultured weekly.

Results:

   The weights of the animals in all groups remained constant throughout the study. Hemotologic and 15 biochemical parameters did not vary among the three groups. Examination and culture of stool samples demonstrated that "MSE" did not affect the baseline fungal and bacterial counts.

   The statistical analysis of the observations made by the odor panel demonstrated that "MSE" did reduce odor significantly as compared with the control room (p<.005). The control room was noted by the panel to have a strong odor. Observation of highested frequency in both test rooms (level 1 and level 2 of "MSE") was a moderate odor. There was not a significant difference in the odor of the dogs receiving a double amount of "MSE" compared with the single or recommended amount.

Note: MSE was marketed under the trade name minus for this study.

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