Research Accomplishment Reports 2009

Enteric Diseases of Swine and Cattle: Prevention, Control and Food Safety

M.C. Newman
Department of Animal and Food Sciences

 

Non-Technical Summary

1) Most food-borne illness events are of undefined etiology, stressing the need for identification and characterization of novel, emerging, or previously unrecognized agents, which undoubtedly account for many of these cases.

2) Most of the known bacterial, viral and parasitic food-borne disease agents are primarily zoonotic in nature.

3) Several of these agents are also severe pathogens of animals or have close relatives that are animal pathogens, such that investigation of the host-parasite relationship in animal models or in fact in the animal populations themselves will be informative regarding the host-parasite interactions in humans.

- Focus on emerging or currently unrecognized agents that result in food-borne human illness or enteric diseases of domestic animals, proposing research on the identification, characterization and development of diagnostics for emerging or currently unrecognized agents.

- Development of effective and practical interventions to reduce prevalence of agents already characterized to be of major importance in food safety and / or animal health, based on research on the ecology of the agents and their epidemiology and population dynamics in animal reservoirs.

- Provide training and continuing education to disseminate knowledge regarding new and emerging agents and interventions effective at reducing enteric disease agent incidence and prevalence.

2009 Project Description

Traditionally determination of the nutritional impact of antibiotics in swine diets have largely focused on effects related to the digestibility and utilization of protein and energy. Recent research has demonstrated that antibiotics may increase P digestibility.

Because of the importance of P in diet cost and in waste management plans, the present study evaluated the potential impact of two antibiotics - bacitracin methylene disalicylate (bacitracin) and tylosin - on P digestibility and pathogen populations in swine. Ileal samples were taken immediately after slaughtering each pig to assess the bacterial profile and digesta pH. Samples consisted of about 60 cm section of the distal ileum and its contents. Sampling involved a double ligation with a cotton thread of both ends of the ileal section, removing the ileum portion, and transporting it on ice to the laboratory for pH determination and bacteria culturing. The quantification of phytate-utilizing bacteria populations, as colony-forming units per gram of ileal contents (CFU/g), was conducted according to the procedure described by Bae et al. (1999). Clostridium perfringens, coliform and Escherichia coli populations were monitored to identify the antibiotics effects on these potential pathogens.

2009 Impact

The effect of the antibiotics on gut microflora failed to demonstrate an effect on the microflora with the exception that tylosin decreased the number of phytate-utilizing bacteria (P = 0.05). Therefore, because these two antibiotics did not demonstrate an improvement in P digestibility, improvements in P digestibility appear to be an antibiotic-specific response rather than a generalized antibiotic response.