Filler (animal food)
In processed animal foods, a filler is an ingredient added to provide dietary fiber, bulk or some other non-nutritive purpose.
Products like corncobs, feathers, soy, cottonseed hulls, peanut hulls, citrus pulp, screening, weeds, straw, and cereal by-products are often included as inexpensive fillers or low-grade fiber content.
Dietary fiber acts as a calming base for forming the stool in the colon, and it should help develop good fecal consistency, in addition to other health benefits such as reduced blood sugar uptake.
According to critics [who?], many commercial pet foods contain fillers that have little or no nutritional value, but are added to decrease the overall cost of the food, especially when pet food manufacturers attempt to keep their pet foods at a desired price point despite rising manufacturing, marketing, shipping, and related costs. Critics [who?] allege that low-grade fiber fillers actually aggravate the intestinal walls instead of promoting health, and that carnivores such as cats are not able to successfully digest vegetable matter.
In rare cases, contaminated fillers have led to large-scale recalls at significant expense to the pet food companies. Two examples are aflatoxin on corn in the 2006 Diamond Dog Food Recall and melamine, which may have contaminated wheat gluten and other protein concentrates in the 2007 pet food recalls.