Ingredients are vehicles for nutrients. All animals big or small have daily nutrient requirements; they do not have specific food item requirements. They need protein, fat, carbohydrates/fibre, vitamins and minerals, and water, in specific amounts. By combining different ingredients, it is possible to meet the daily nutritional requirements of your dog or cat. The best products will be formulated with highly digestible ingredients that provide the highest quality of these nutrients in an extremely palatable format. In other words, the quality of a food does not start OR end at the face value of the ingredient deck. It takes science, research, innovation, expertise, and clinical trials to provide optimal nutrition.
A raw material can only ever be as good as the animal it came from. A healthy feed animal will have a healthy muscle mass, a good ratio of muscle to fat, and specific nutrient levels within different organs. Conversely, an unhealthy animal may be under or overweight, have poor muscle condition or quality, and have nutrient deficiencies or excesses that affect the nutrient profile of different organs. An ingredient label will tell you the species the raw material comes from, but it will not indicate the health status of the animal when it was slaughtered.
Nutrient content of tissues will fluctuate in an individual throughout the year depending on time of year, temperature and other environmental factors. A study by Gökçe et al 2004 reported a significant fluctuation in the level of EPA/DHA in sole according to the time of year, ranging from 3.36–4.26% of total lipid and 18.75–20.23% of total lipid depending on the season. Similarly, nutrition of the food animal will impact the nutrient profile it produces1 when incorporated into a pet food formula. An ingredient label will tell you the species the raw material comes from, but it will not indicate the nutrient profile it provides, the time of year it was slaughtered, or the nutrition the animal received prior to slaughter.
Different organs provide different nutrient profiles, for example; bone contains increased levels of minerals including calcium, liver contains increased levels of vitamins, cardiac tissue contains increased levels of the amino acids taurine and L-carnitine. Hand sorting is the process of separating different organs (ie: separating hearts from livers). Trimming is the process of removing undesired portions from the material (ie: removing fatty skin from chicken neck). Without sorting and trimming there is an increased variability of nutrient content from batch to batch, which decreases nutritional precision, and could cause nutrient levels to fall above or below the predetermined target.
The quality of animal tissues begins to deteriorate at the time of slaughter. A variety of factors contribute to spoilage including micro-organisms, exposure to air, and improper freezing, processing, or storing techniques2,3. An ingredient label will tell you the species the raw material comes from, but it will not indicate how it was stored, transported, or processed.
Cooking alters protein structure5,6 and potentially affects digestibility and nutritional value. In same instances digestibility increases5, while in others nutrient value decreases.
In fact, processing and cooking will impact the digestibility and nutritional value of the entire formula. It’s important that production is finely regulated in order to optimize digestibility, and avoid or account for any decrease in nutritional value in the cooking process. What processes are in place to ensure optimal nutrition and digestibility? It is up to the pet food companies to decide.
Just like a Granny Smith apple is different from a Red Delicious apple, different crop varieties of any plant ingredient will differ from each other. Differences in digestibility, palatability, protein levels, amino acid amounts, and other nutrient levels can vary greatly according to the variety chosen7, 8.
In addition to different weather patterns and temperatures, different soil types develop in different climates9. Soil quality, including nutrients in the soil, moisture level, and compaction, all play a significant role in determining the quality of the produce that grows in it10. An ingredient label will tell you the species the raw material comes from, but it will not indicate the growing conditions.
Storage of raw materials is an extremely important factor in ingredient quality. The length of time cereal can be safely stored is affected by the conditions at the time of harvest, as well as the storage facility being used. Factors that affect stored material include moisture, temperature, condition of the ingredient, and oxygen level in the storage facility. Improperly stored raw material can grow moulds and bacteria or be infested with rodents, mites, beetles, and other pests11.
In addition to potential naturally contamination from improperly stored raw material, pet food manufacturers need to be aware of the risk of the potential for contamination from handling the material, which can occur intentionally or by accident. It is easy to run tests on raw material when you know what you’re looking for, for example, mycotoxins and insects, however it is much more difficult to identify a contaminant if you’re not aware of the potential problem12. What protocols are in place to ensure safety and quality of raw materials? It is up to the pet food companies to decide.
Very fine grinding of raw materials in preparation for cooking increases the digestibility and therefore availability of nutrients4. An ingredient label will tell you the name of the raw material, but it will not indicate the digestibility of that ingredient, or of the formula as a whole.
References 1. Karalazos et al. 2011. Influence of the dietary protein:lipid ratio and fish oil substitution on fatty acid composition and metabolism of Atlantic salmon (Salmo salar) reared at high water temperatures. Br J Nutr. 105(7):1012-25. 2. Bruckner et al. 2012. Influence of cold chain interruptions on the shelf life of fresh pork and poultry. International Journal of Food Science & Technology. 47:8;1639–1646. 3. Lawrie RA. Ledward DA. 2006. Lawrie’s meat science (7th ed.). Cambridge: Woodhead Publishing Limited. 4. . National Research Council (NRC). 2006. Nutrient Requirements of Dogs and Cats. The National Academies Press, Washington, DC, USA. 5. Huang et al. 2011. Influence of heat on protein degradation, ultrastructure and eating quality indicators of pork. J Sci Food Agric. 91(3):443-8. 6. Santé-Lhoutellier et al. 2008. Effect of meat cooking on physicochemical state and in vitro digestibility of myofibrillar proteins. J Agric Food Chem. 56(4):1488-94. 7. Shurson et al 2005. Corn by-product diversity and feeding value to non-ruminants Proc. MN Nutr. Conf. 8. Babcock B et al. 2008. Using distillers grains in the U.S. and international livestock and poultry industries. MATRIC, The Midwest Agribusiness Trade, Research and Information Center. Iowa USA. Available at: http://www.card.iastate.edu/books/distillers_grains/pdfs/distillers_grains_book.pdf 9. American Geosciences Institute. Accessed on Sept 2012: http://www.agiweb.org/environment/publications/powerpoints/SoilTypes.ppt) 10. Miransari et al. 2009. Effects of soil compaction and arbuscular mycorrhiza on corn (Zea mays L.) nutrient uptake. Soil and Tillage Research. 103(2): 282–290. 11. Canada Grain Council’s Complete Guide to Wheat Management. 2002. Canada Grains Council. 12. Hui YH. 2007. Handbook of Meat, Poultry and Seafood Quality (ed L. M. L. Nollet). Blackwell Publishing, Ames, Iowa, USA.
Like humans, dogs can be allergic to ragweed, grass, pollens, molds and dust mites. Humans’ seasonal environmental allergies are typically identified by sneezing, running nose, and red irritated watery eyes but when a dog is affected by seasonal environmental allergies the typical symptoms are much different. #ItchyPetSeeYourVet