Zignature vs. Purina Pro Plan

Liver is a controversial ingredient because the source animal is not specified. Anonymous animal ingredients are typically very low quality and may contain almost any animal, including dogs and cats!

Poultry is a controversial ingredient because the source animal is not specified. Anonymous ingredients such as poultry are typically low-quality ingredients in comparison to named protein sources (e.g. chicken, turkey, duck).

Canola oil is a plant-derived oil from the seeds of canola plants. Although fat is an essential component of any diet, canola oil is controversial in pet food. Proponents claim that canola oil provides a better fat profile in comparison to other plant based oils. However, opponents claim that canola oil is typically produced with genetically modified rapeseed and that rapeseed oil has multiple adverse health affects.

Corn grits are made from ground corn. Corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

In regards to digestibility, the claims of "highly digestible" are only true if corn is processed into a meal or flour and subsequently cooked. In regards to the protein contribution, we must note that corn is a plant based protein which does not contain all of the necessary amino acids required by pets to sustain life. Therefore substituting corn for meat is an unsuitable substitution and actually degrades the overall protein quality of the product.

Finally, we'll discuss the claims about vitamins and minerals in corn. Although corn does provide many vitamins and minerals, it not necessarily an exceptional ingredient in this regards. There are many other ingredients which are more complete and biologically appropriate. Therefore the usage of corn as the primary ingredient in pet food should certainly warrant further questioning.

Canola meal is a high protein by-product of canola oil production. This ingredient is marked controversial because it may be derived from genetically modified rapeseed, which is associated with multiple adverse health affects.

Pea protein is produced by removing the starchy parts of peas. Pea protein is considered controversial because it provides a substantial plant based protein boost. This boost is undesirable because plant based protein is typically lower in biological value when compared to meat based proteins.

Brewer's rice is the small fragments of rice kernel that are separated from the larger kernels of milled rice. The fragments do not contain the same nutrition profile of the whole kernel and therefore brewer's rice is a lower quality grain. Brewer's rice is typically regarded as an inexpensive and low quality filler.

Ground wheat is regarded as an inexpensive and low-quality filler in pet food. However, wheat does provide plant-based protein and makes pet food more affordable for consumers. It's important to note that plant based protein does not provide the same amino acid profile as meat based protein.

Wheat gluten is the main protein of wheat. Although wheat gluten is mostly protein, wheat gluten is considered controversial because it significantly boosts the protein content of the product. This is undesirable because plant based protein does not provide the same amino acid profile as meat based protein.

Animal digest is the result of undecomposed animal tissue after hydrolysis, a chemical reaction. It is typically used as flavoring to improve taste. Animal digest is considered by many as an undesirable low-quality ingredient. What's more, the source animal is not specified and therefore animal digest can contain almost any animal, including dogs and cats!

Caramel color is a concentrated form of caramel, a natural food colorant. Caramel color has been linked to cancer in laboratory animals. Since our pets do not care about food color, caramel color is an unnecessary addition with possible health risks.

Garlic powder in very small quantities can be an acceptable addition, however, garlic can also be toxic. Therefore many pet owners choose to completely avoid garlic.

Soybean flour contains more than 50% protein. Therefore, soybean can significantly boost the protein content of the product. The inclusion of non-meat protein typically degrades the overall quality of protein in the recipe. This degradation is due to the inferior amino acid profile of plant based proteins.

Soybean hulls are a by-product of soybean oil and meal processing. They are typically regarded as low quality and inexpensive fillers which lack any significant nutritional value.

Specific vegetable oils are typically positive ingredients; however, this ingredient does not specify which vegetable(s) were used to produce the oil.

Without this information, it is impossible for us to make any specific statements. With any fat source, it is important to know the omega-3 to omega-6 fatty acid ratio, a property which cannot be determined with this ingredient. Thus, we have marked vegetable oil as a controversial ingredient.

Corn germ meal is a high protein by-product of the oil extraction process from corn (maize). It's considered controversial because plant based protein does not contain all of the necessary amino acids required by pets to sustain life. Therefore substituting corn germ meal protein for meat based protein is an unsuitable substitution and actually degrades the overall protein quality of the product.

Poultry giblets includes the heart, liver, gizzards, and other internal organs of poultry. Organs are nutritiously dense ingredients which provide high quality protein and fat. However, this particular ingredient is considered an anonymous meat ingredient because the type of poultry is not specified. In order words, "named" giblets such as chicken giblets or turkey giblets are preferred over poultry giblets.

Corn gluten meal is a by-product from the production of various corn products (corn starch, corn syrup, etc). It's very high in protein (nearly 60% protein) and therefore can significant boost the protein content of the product. Because plant based proteins such as corn gluten meal are inferior to meat based proteins (lack many essential amino acids), they are not suitable substitutes.

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, meat by-products contain nearly all parts of the animal which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

This ingredient is marked controversial because the meat source is not identified. Anonymous ingredients such as meat by-products are typically very low quality additions. The most unpleasing property of this ingredient is that the animal source can contain any mammal, even dogs & cats.

Whole grain corn is the entire corn kernel (the germ, bran, and endosperm). Corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

In regards to digestibility, the claims of "highly digestible" are only true if corn is processed into a meal or flour and subsequently cooked. In regards to the protein contribution, we must note that corn is a plant based protein which does not contain all of the necessary amino acids required by pets to sustain life. Therefore substituting corn for meat is an unsuitable substitution and actually degrades the overall protein quality of the product.

Finally, we'll discuss the claims about vitamins and minerals in corn. Although corn does provide many vitamins and minerals, it not necessarily an exceptional ingredient in this regards. There are many other ingredients which are more complete and biologically appropriate. Therefore the usage of corn as the primary ingredient in pet food should certainly warrant further questioning.

Whole grain wheat contains the entire grain of wheat (the germ, bran, and endosperm). Wheat is the second most-produced cereal grain in the world (corn is the first). Although wheat is a controversial ingredient, it is not necessarily undesirable because it provides dietary fiber and many other nutrients. However, wheat contains a notable amount of plant based protein, which is inferior to meat based protein and therefore an undesirable substitution.

Wheat is also one of the most common ingredients to cause food allergies or intolerance. However, grains such as wheat are typically low offenders in comparison to certain protein sources (such as beef).

Ground yellow corn is a cereal grain which provides a modest amount of vitamins, minerals, and plant based protein. It also happens to be one of the most controversial ingredients in pet food.

Proponents of corn claim that corn is highly digestible and an excellent source of protein, energy, vitamins, minerals, and essential fatty acids.

Opponents however believe that positive claims in regards to corn are either half-truths or completely false, we'll discuss a few of the opposing arguments.

In regards to digestibility, the claims of "highly digestible" are only true if corn is processed into a meal or flour and subsequently cooked. In regards to the protein contribution, we must note that corn is a plant based protein which does not contain all of the necessary amino acids required by pets to sustain life. Therefore substituting corn for meat is an unsuitable substitution and actually degrades the overall protein quality of the product.

Finally, we'll discuss the claims about vitamins and minerals in corn. Although corn does provide many vitamins and minerals, it not necessarily an exceptional ingredient in this regards. There are many other ingredients which are more complete and biologically appropriate. Therefore the usage of corn as the primary ingredient in pet food should certainly warrant further questioning.

Powdered cellulose is produced from minuscule pieces of wood pulp and plant fibers. Other than its fiber content, powdered cellulose lacks any nutritional contribution.

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, chicken by-products contain nearly all parts of the chicken which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

Like other meat by-products, chicken by-products are considered controversial, mainly because they are inexpensive ingredients which consumers have equated with slaughterhouse waste. However, manufactures and many experts claim that animal by-products are unjustly criticized. Proponents state that "named" by-products, such as chicken by-products, supply many important nutrients required by pets.

By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, poultry by-products contain nearly all parts of poultry which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

Like other meat by-products, poultry by-products are considered controversial, mainly because they are inexpensive ingredients which consumers have equated with slaughterhouse waste. However, manufactures and many experts claim that animal by-products are unjustly criticized. Proponents state that by-products, such as poultry by-products, supply many important nutrients required by pets. Finally, we must also note that this ingredient is considered an anonymous meat ingredient because the specific type of poultry is not specified. By-products which are "named", such as chicken by-products are typically higher in quality when compared to the more general poultry by-products.

Chicken by-product meal is produced by cooking chicken by-products using a process called rendering. By-products are defined by AAFCO as the "non-rendered, clean parts, other than meat, derived from slaughtered mammals." Thus, chicken by-products contain nearly all parts of chickens which are typically not consumed by humans. These parts include the liver, lung, spleen, kidney, stomach, blood, intestine, bone, etc.

Like other meat by-products, chicken by-products are considered controversial, mainly because they are inexpensive ingredients which consumers have equated with slaughterhouse waste. However, manufactures and many experts claim that animal by-products are unjustly criticized. Proponents state that "named" by-products, such as chicken by-products, supply many important nutrients required by pets.

Poultry by-product meal is a controversial ingredient because the source animal is not specified. Anonymous ingredients such as poultry by-product meal are typically low-quality ingredients in comparison to named protein by-product meals (e.g. chicken by-product meal, turkey by-product meal, duck by-product meal).

Soy protein isolate is a highly refined/purified form of soy bean protein. Roughly 90% of soy protein isolate is protein. The inclusion of non-meat protein typically degrades the overall quality of protein in the recipe. This degradation is due to the inferior amino acid profile of plant based proteins.

Soybean protein concentrate is produced by removing the water soluble carbohydrates from soybeans. The inclusion of non-meat protein typically degrades the overall quality of protein in the recipe. This degradation is due to the inferior amino acid profile of plant based proteins.

Animal fat is a by-product of tissue rendering. The source animal is not specific and therefore we cannot be certain that the source does not include diseased animals or even euthanized dogs and cats.

Butylated hydroxyanisole (BHA) is an artificial preservative and possible cancer-causing agent. Studies have show that BHA can be linked to various tumors in laboratory animals.

Butylated hydroxytoluene (BHT) is an artificial preservative and possible cancer-causing agent. BHT is banned in several countries, but the FDA has classified BHT as "generally recognized as safe."

Corn oil is extracted from the germ of corn kernels. It contains an omega-6 to omega-3 fatty acid ratio of 49:1. Corn oil's unfavorable omega-6 to omega-3 fatty acid ratio makes it an undesirable ingredient. Consumption of such ingredients can lead to an array of health problems in both animals and humans.

Yellow 5 is an artificial dye which may be contaminated with several cancer-causing chemicals. Like other dyes, yellow 5 does not provide any nutritional value.

The ingredient "added color" is ambiguous and may include various artificial dyes. Most artificial dyes have been linked to various chronic diseases.

Menadione sodium bisulfate complex is a synthetic version of vitamin K that has been linked to many health concerns. Research has suggested possible toxic reactions in liver cells and red blood cells among other serious problems. In fact, one large chemical supplier warns, "The substance is toxic to kidneys, lungs, liver, mucous membranes. Repeated or prolonged exposure to the substance can produce target organs damage."

Menadione sodium bisulfite complex is a synthetic version of vitamin K that has been linked to many health concerns. Research has suggested possible toxic reactions in liver cells and red blood cells among other serious problems. In fact, one large chemical supplier warns, "The substance is toxic to kidneys, lungs, liver, mucous membranes. Repeated or prolonged exposure to the substance can produce target organs damage."

Pork fat is typically collected while cooking pork using a process called rendering. Pork fat is a relatively high quality source of essential fatty acids. In particular, pork fat is high in linoleic acid, an important omega-6 fatty acid. Unfortunately, this ingredient is preserved with TBHQ, an artificial preservative.

Animal fat is a by-product of tissue rendering. The source animal is not specific and therefore we cannot be certain that the source does not include diseased animals or even euthanized dogs and cats. What's more, this ingredient is preserved with TBHQ, an artificial preservative.