Hi all
The use and misuse of antibiotics is hardly new. Livestock producers have been routinely feeding large quantities for decades. And not just for their antimicrobial function, but as a growth promoter. I have heard of beekeepers doing the same thing. I think this warrants a broader discussion, especially since veterinarians are now involved in bee husbandry. 

> Shortly after the introduction of the therapeutic use of antibiotics, the growth-promoting effect of these products in chickens was discovered by feeding fermentation offal from the chlortetracycline production of Streptomyces aureofaciens. Several antibiotics have been in use as growth promoters of farm animals ever since. The introduction of these agents coincided with intensive animal rearing. These products improved feed conversion and animal growth and reduced morbidity and mortality due to clinical and subclinical diseases. The average growth improvement was estimated to be between 4 and 8%, and feed utilization was improved by 2 to 5%. 

> The mechanisms of growth promotion are still not exactly known. Experiments with germ-free chickens have seemed to indicate that the action of the growth promoters is mediated by their antibacterial effect. Four hypotheses have been proposed to explain their action: (i) nutrients may be protected against bacterial destruction; (ii) absorption of nutrients may improve because of a thinning of the small intestinal barrier; (iii) the antibiotics may decrease the production of toxins by intestinal bacteria; and (iv) there may be a reduction in the incidence of subclinical intestinal infections. 

> The use of antibiotics as feed additives has been a hallmark of modern animal husbandry, but this widespread practice is not without criticism. In the early years, all antibiotics were allowed for use, although some did not enhance growth and many were too expensive. The first discussions on the use of antibiotics as growth promoters began in the late 1960s and resulted in the “Swann Report,” which was issued in the United Kingdom. n The Swann Report proposed that antibiotic use for growth promotion should be restricted to antibiotics that (i) make a significant economic difference in the raising of livestock, (ii) have little or no application as therapeutic agents in humans or animals, and (iii) do not impair the efficacy of a prescribed therapeutic drug through the development of resis- tant strains. It was suggested that antibiotic residues in meat would not impair human health. Specifically, it was recommended that the use of penicillins, tetracyclines, tylosin, and sulfonamides as growth promoters be discontinued. 

Butaye, P., Devriese, L. A., & Haesebrouck, F. (2003). Antimicrobial growth promoters used in animal feed: effects of less well known antibiotics on gram-positive bacteria. Clinical microbiology reviews, 16(2), 175-188.

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> In 1971, the UK withdrew authorisation for use of several substances as growth promoters, including tetracyclines and penicillin. Other countries followed suit and a comprehensive ban on the use of all antibiotics as growth promoters was eventually introduced in the EU in 2006. Researchers are looking everywhere for new ideas for ways to fight bacteria, both to treat or prevent disease, and to replace the use of antibiotics as growth promoters.

> In North America, there are very few regulations on antibiotic use in agriculture. However, the US Food and Drug Administration produced guidance in 2012 on the “judicious use” of antimicrobials in the rearing of animals for food production. 

> Specific regulatory strategies include: 1) eliminating the use of antibiotics as growth promoters in food animals; 2) requiring that antibiotics be administered to animals only when prescribed by a veterinarian; and 3) requiring the antibiotics identified as critically important in human medicine - especially fluoroquinolones and third- and fourth-generation cephalosporins - only be used in food animals when their use is justified.

Owens, B. (2018). Strategies to reduce the use of antibiotics in animals. Stroke, 13, 57.

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Bear in mind that I do not think the use of antibiotics in bees should be regulated the same way as in other livestock, for several reasons, but neither should they be used as growth promoters. Antibiotics are too precious to squander.

PLB

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