Farming antibiotics

The polyether antibiotics were first recognized as a separate class with the pubHcation of the structure of monensia ia 1967 (1). Several members of the group have siace found commercial appHcation as anticoccidials ia poultry farming and ia improvement of feed efficiency for mmiaants (see Feeds and FEED additives). 

The nature of the conditions of intensive production, however, can increase the risk of diseases and infections which can spread very rapidly and devastate large numbers of animals." Thus it is common practice for producers of poultry to add coccidiostats to their diets and vaccines to their drinking water in order to prevent coccidiosis and other infectious diseases such as bronchitis and Newcastle disease. A similar problem exists for intensively reared fish, where it is necessary to add antibiotics to their diets. A problem with intensively reared fish is that their diet is added directly into the water in which they live thus drugs and other additives in the diet are relatively easily dispersed into the local environment of fish farms, where they can increase bacterial resistance and also cause problems such as algal blooms. 

A further aspect that may add to the development work relates to the method of administration. In addition to the standards methods of administration associated with human medicines, veterinary medicines may be introduced to animals through medicated feeds. Such practices have been most commonly associated with the use of antibiotics or other substances to enhance animal performance under intensive farming systems. The use of medicated feeds has been phased out in Europe since the end of 2005, with the exception of coccidiostats and histomonostats intended to kill or inhibit protozoa. In the U SA, however, medicated feeds are still commonplace. Thus, the developer may have to consider the stability and appropriate labelling of the drug when compounded into medicated feeds. 

Holmstrom K, Graslund S, Wahlstrom A, Poungshompoo S, Bengtsson BE, Kautsky N (2003) Antibiotic use in shrimp farming and implications for environmental impacts and human health. Int J Food Sci Technol 38 255-266... 

Ghosh S, LaPara TM (2007) The antibiotic use in farm animals on the proliferation and persistence of antibiotic resistance among soil bacteria. ISME J 1 191-203... 

Given the diversity of disease-causing organisms, the interactions between farm-specific environmental factors and the types of mastitis causing pathogens found, the potential efficacy of antibiotic treatments can only be assessed accurately in the context of the specific on-farm conditions. Furthermore, many recent investigations concluded that, except for some specific infections caused by streptococci, a prophylactic and or longer-term use of antibiotics for chronic and sub-clinical mastitis should not recommended in the future (Deluyker et al., 2005). 

Important preconditions for the successful development and implementation of farm-specific mastitis management plans are that (i) the farmer realises that there is a problem and is committed to reducing both mastitis prevalence and antibiotic use and (ii) that the farm s veterinarian is involved and committed to the improvement plan. Once these preconditions are met, development and implementation of plans then involves four stages. 

For example, protection of the milk supply from contamination with antibiotics can be done at a relatively low cost at the farm, where the main costs are recurrent costs related to ensuring that the milk from treated cows... 

If both the farms and the dairy are covered by a reliable control system, the everyday monitoring will take place at the optimal CCP at the farm and analysis of milk samples at the dairy will only be needed at low frequency for verification of the system (Principle 6). This will ensure that there are no antibiotic residues in the milk sold by the dairy, with minimal expenses for control. In fact, the most expensive item will be the cost of the unannounced inspections at the farms to monitor the integrity of the system. However, if not all the farms are covered by a sufficiently good control system, the dairy will have to add the extra costs of its own independent system, in order to be able to take responsibility for this quality aspect. So the main benefit of a supply chain-based system is that it provides full control at the lowest cost. The main drawback is that the more entities that are involved, the greater is the risk that one of them will experience a system failure and this can have disastrous consequences for all those other entities that rely on the defaulting entity for their product control. 

As occurred with the other antibiotics, commercial immunoassay formats, also available as kits for tetracyclines and penicillins such as the Parallux, the LacTek, or the Charm II, have also been placed on the market for the analysis of sulfonamides (see Table 4). Thus, the Parallux detects sulfamethazine and sulfadimethoxine in raw milk with a LOD of 10 pg L1. The Charm II detects almost all sulfonamides in honey and milk with a LOD in the range from 1 to 10 pg L, whereas LacTek is able to detect sulfamethazine. Moreover, the 5101SULlp and 5101SUDAlp tests reach LOD values for sulfamethazine and sulfadiazine of around 0.2 pg L 1 and they have been applied to the analysis of urine, milk, and plasma. These tests have proved to be efficient as a point of care for on-site applications on farms. Moreover, commercially available antibodies can be found from several sources such as Silver Lake Research, US Biological, Cortex Biochem. Inc., Accurate Chemical Scientific, Fitzgerald Industries International Inc., and Biotrend Chemikalien GmbH. 

Another important source of antibiotics in human diet is through the ingestion of farmed fish. Farmed fish and shrimp are produced in crowded facilities with inadequate or nonexistent regulation of antibiotic use. The detection of chloramphenicol... 

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