It is not recommended for cats to eat oysters because of the enzymes and possible bacteria found in them.
Oysters are molluscs with hard shells that can be found in marine or brackish habitats. Though they are safe for humans to eat, they should not be fed to cats. Bacteria in raw oysters such as Vibrio vulnificus may cause your cat to suffer from stomach and intestinal complications. Diarrhea and dehydration are two common symptoms, which can escalate to death in extreme cases.
Aside from possible bacteria lurking in the oysters, the seafood contains enzymes that destroy the thiamine found in your cat’s body. Thiamine is an essential vitamin that helps cats maintain optimal health. Thiamine deficiency can initially manifest as appetite loss, weight loss, and gastrointestinal upset. As it progresses, cats may suffer from neurological symptoms including neuromuscular weakness, unequal pupil sizes, decreased light response, and heart problems.
What to do if your cat accidentally eats oysters: Find out how much your cat ate, and if she consumed raw or cooked oysters. If it is the latter variety, find out the accompanying ingredients used to prepare it.
Ingesting common ingredients such as salt, garlic, and onion may cause her to immediately display alarming symptoms. Salt consumption can cause vomiting, diarrhea, decrease in appetite, lethargy, incoordination, and excessive thirst or urination. Garlic and onion consumption may result in vomiting, blood in urine, weakness, high heart rate, panting, fever, skin discolouration, appetite loss, abdominal pain, and breakdown of red blood cells. Meanwhile, oysters cooked with dairy products such as cheese and butter may cause digestive upset.
In summary: Though oysters contain omega-3 fatty acids that may enhance your cat’s brain function and reduce her risk of having cardiac diseases, she is better off eating other sources that are completely safe for her. Consult with your veterinarian to discover which human-grade food you can safely give your cat. You can also find out which seafood you can safely feed to your cat under our blog’s “can cats eat” category.