Antibiotics animals

Antibiotic Animal Acute oral toxicity (LDso mg/kg)... 

Antibiotics Animal feed Methanol/acetic acid 15... 

Macrolide antibiotics Animal feeding stuff RP-HPLC Coulometric-array [154]... 

When treatment chemicals have to be employed, they may be iacorporated ia the food, used ia dips, flushes and baths, or allowed to remain ia the water for exteaded periods. Siace oae of the first respoases of aquatic animals to disease is reduction or cessation of feeding, treatments with medicated feeds must be initiated as soon as development of an outbreak is suspected. Antibiotics, such as terramycin, can be dissolved in the water, but may be less effective than when given orally. 

Nonnutrient Additives. Nonnutritional dietary additives provide antioxidants to preserve freshness, flavor enhancers to stimulate food selection, color to meet the owner s expectations, pellet biaders to minimi2e fine particles, mycostats to minimi2e mold growth, and iagredient-flow enhancers. Pet foods do not iaclude coccidiostats, antibiotics, added hormonal materials, and fly-larval iasecticides used ia other animal feeds. 

Antibiotics (qv) have been fed at subtherapeutic levels to promote mminant animal growth. Possible reasons for the observed growth include decreased activity of microbes having a pathogenic effect on the animal, decreased production of microbial toxins, decreased microbial destmction of essential nutrients, increased vitamin synthesis or synthesis of other growth factors, and increased nutrient absorption because of a thinner intestinal wall... 

Lactic Acid B cteri. The lactic acid bacteria are ubiquitous in nature from plant surfaces to gastrointestinal tracts of many animals. These gram-positive facultative anaerobes convert carbohydrates (qv) to lactic acid and are used extensively in the food industry, for example, for the production of yogurt, cheese, sour dough bread, etc. The sour aromatic flavor imparted upon fermentation appears to be a desirable food trait. In addition, certain species produce a variety of antibiotics. 

Table 1. Benefits of Subtherapeutic Level of Antibiotic in Food-Producing Animals, % Improvement...

Mechanism of Action. The mechanisms by which antibiotic adrninistration at subtherapeutic levels enhance growth rate and efficiency of gain in growing animals have not been clarified. Possible modes of action include disease control, nutrient sparing, and metaboHc effects. There is extensive evidence that the principal benefit from subtherapeutic use of antibiotics results from the control of harmfiil microorganisms. 

The nutrient sparing effect of antibiotics may result from reduction or elimination of bacteria competing for consumed and available nutrients. It is also recognized that certain bacteria synthesize vitamins (qv), amino acids (qv), or proteins that may be utilized by the host animal. Support of this mode of action is found in the observed nutritional interactions with subtherapeutic use of antibiotics in animal feeds. Protein concentration and digestibiHty, and amino acid composition of consumed proteins may all influence the magnitude of response to feeding antibiotics. Positive effects appear to be largest... 

The therapeutically active dmg can be extracted from plant or animal tissue, or be a product of fermentation (qv), as in the case of antibiotics. Frequentiy, it is synthesized and designed to correlate stmcture with therapeutic activity. Pharmacologic activity is first tested on laboratory animals. When the results ate encouraging, physical and chemical properties are determined in the so-called preformulation stage, and analytical procedures are developed for quahty control (see Qualityassurance/qualitycontrol). 

The presence of many nonprotein amino acids has been reported in various living metaboUtes, such as in antibiotics, some other microbial products, and in nonproteinaceous substances of animals and plants (7). Plant amino acids (8) and seleno amino acids (9) have been reviewed. 

Veterinary Applications. Another use for antibiotics is for veterinary appHcations and for animal feed supplements to promote growth in Hvestock (see Feeds and feed additives). Feed antibiotics used in the United States far surpass all other agricultural appHcations in terms of kilogram quantities used and approach quantities used in human medicines (25). In 1980 the USA feed antibiotic usage was estimated to be between five and six million kg. The U.S. Council of Agricultural Science and Technology estimates that feed additives save the U.S. consumer approximately 3500 million per year in meat prices, and antibiotic use accounts for most of this. 

Coccidiosis is a proto2oal disease of the intestinal tract of animals that leads to severe loss of productivity and death. The development and widespread use of anticoccidials has revolutionized the poultry industry. The estimated world market for anticoccidial agents in 1989 was 425 million and this was dominated by the polyether ionophore antibiotics monensin, salinomycin [53003-10-4], n imsm [55134-13-9], la.s9locid, and maduramicin [84878-61-5] (26). 

Veterinary Potential or Fiorfenicol. The absolute ban on the use of chloramphenicol ia food producing animals ia the United States and Canada has accentuated the need for an effective broad spectmm antibiotic ia animal food medicine. Fiorfenicol and other antibiotics commonly used ia veterinary medicine have been evaluated in vitro against a variety of important veterinary and aquaculture pathogens. Some of these data ate shown in Tables 4 and 5, respectively. Fiorfenicol was broadly active having MICs lower than those of chloramphenicol in each of the genera tested (Table 4). Florfenicol was also superior to chloramphenicol, thiamphenicol, oxytetracycline [79-57-2] ampicillin [69-53-4] and oxolinic acid [14698-29-4] against the most commonly isolated bacterial pathogen of fish in Japan (Table 5) (37). 

Antibiotic LL-E19020a and LL-E19020P are described as useful agents for the treatment of chronic respiratory disease, fowl cholera, and necrotic enteritis in birds (76) and as anthelmintics in monogastric and mminant animals (28). 

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