What is the name of the synthetic antibiotic/anti-inflammatory agent used to treat giardiasis in animals?

Metronidazole is the correct choice as it is specifically recognized for its effectiveness in treating giardiasis in animals. Giardiasis is caused by the protozoan parasite Giardia, which affects the intestines of various animals. Metronidazole works by disrupting the DNA synthesis of anaerobic bacteria and protozoa, making it particularly useful for this type of infection.

In veterinary medicine, it is commonly used to eliminate Giardia parasites, as it directly targets the organisms without causing significant harm to the host. This characteristic makes it a preferred choice for managing giardiasis compared to other antibiotics.

The other options listed are not primarily used for giardiasis; for instance, amoxicillin is a broad-spectrum antibiotic effective against various bacterial infections but not effective against protozoal infections like Giardia. Tetracycline is also an antibiotic that targets certain bacteria but does not have the same efficacy against protozoal infections as metronidazole does. Enrofloxacin, while a potent antibiotic for treating various bacterial infections, is not indicated for giardiasis, as its action is primarily against bacteria rather than the protozoa responsible for this condition. Thus, metronidazole stands out as the appropriate treatment option in this case.