Fish often reigns supreme as the quintessential cat food in common perception and even in various media depictions. However, scratch beneath the surface of this popular image, and an unexpected truth emerges. Some fish can be a treat but offering it raw can actually expose our feline friend to a range of serious health risks.
The Dangers of Going Raw: Why Raw Fish is Bad For Cats
1. General Dangers of Raw Meat
Raw food or raw meat might be the most natural diet for pets. This could be the reason why raw pet food sales in North America have increased at least 15 percent each year and about 15 to 25 percent of dogs and 10 percent of cats are fed some raw meat. But raw meat is not the safest food option for both dogs and cats because it exposes them to pathogens.
Canadian veterinarian Lea Stogdale noted that cats and dogs can handle bacteria in raw meat most of the time because of the consistent acidity of their stomach fluid. However, those with suppressed or weakened immune systems due to a particular disease are more prone to infection. Humans can also be infected due to unsafe food handling and improper fecal disposal.
2. Specific Pathogens from Raw Fish
Raw fish can carry and transmit parasites like Anisakis and bacteria such as Salmonella, Listeria, and Clostridium. Anisakis is a roundworm that causes gastritis, vomiting, and abdominal pain. It may embed in the stomach or intestinal lining and cause inflammation or blockages. Salmonella can result in blood infection in young, elderly, and immunocompromised cats.
Listeria causes listeriosis which can lead to fever, vomiting, diarrhea, and neurological symptoms like incoordination or seizures. Clostridium produces potent toxins in the gut. These can damage the lining of the intestines and cause gastroenteritis or even hemorrhagic diarrhea. Cats can become asymptomatic carriers of bacteria and shed them to infect humans later on.
3. Mercury and Other Heavy Metals
Large fish like salmon and tuna are on the upper levels of the marine food chain. This means that heavy metals like mercury can accumulate in their tissues and organs over time through the process called bioaccumulation and biomagnification. Ingestion of mercury is common when consuming fish like tuna and salmon. This metal cannot be removed by cooking alone.
The better alternatives to salmon and tuna are small and low-mercury cooked fish species like sardines, anchovies, or mackerel. It is still advisable to avoid feeding fish each day. The best option is to either rotate fish with poultry or other protein sources or serve commercial cat food products from reputable manufacturers that contain tested and balanced formulas.
4. High Risk of Thiamine Deficiency
Raw fish, especially certain types like herring, carp, and some others, contain an enzyme called thiaminase. This enzyme breaks down thiamine or vitamin B1. Specifically, when cats consume raw fish that contain thiaminase, this enzyme destroys the thiamine in their food or body before it can be absorbed or used. This leads to thiamine deficiency over time.
Cats have a high demand for thiamine and cannot synthesize it on their own. It plays a key role in their energy metabolism, proper nerve function, and muscle control and coordination. Symptoms of thiamine deficiency include loss of appetite, vomiting, muscle weakness, stumbling or loss of coordination, heat tilting, seizures, and in severe and prolonged cases, coma.
5. Injuries From Raw Fish Consumption
Feeding cats raw fish can lead to physical injuries, particularly from fish bones, which are small, sharp, and difficult to detect. Small bones in raw fish are a choking hazard because they can get lodged in their throats. Fish bones can also be sharp enough to cause cuts or tear the lining of their mouth, throat, esophagus, and stomach. This can further result in inflammation and infection.
Moreover, even if bones are not sharp enough to puncture, they can still get stuck in the digestive tract. Blockages may cause vomiting, constipation or loss of vowel movement, and loss of appetite. This is an emergency situation that requires veterinary intervention. Severe cases would require surgeries. Chewing raw fish bones can also cause broken teeth and mouth ulcers.
FURTHER READINGS AND REFERENCES
- Stogdale, L. 2019. “One Veterinarian’s Experience with Owners Who are Feeding Raw Meat to Their Pets.” In The Canadian Veterinary Journal. 60(6): 655-658. PMID: 31156268
- Villaverde, C. and Chandler, M. 2022. “Commercial vs Homemade Cat Diets: What you need to know.” In Journal of Feline Medicine and Surgery. 24(5): 415-428. SAGE Publications. DOI: 1177/1098612×221090389