Nutrition myths (Proceedings)
MYTH: Meat by-products are inferior in quality compared to whole meat in a diet...
When listed on an ingredient label, meat is defined by the AAFCO as any combination of skeletal striated muscle or that muscle found in the tongue, diaphragm, heart, esophagus with or without the accompanying and overlying fat and the portions of the skin, sinew, nerve and blood vessels which normally accompany the muscle derived from part of whole carcasses. It also must be suitable for use in animal foods. This excludes feathers, heads, feet and entrails. Meat by-products are defined as non-rendered, clean parts of the carcass which may contain lungs, spleen, kidneys, brain, liver, blood, bone, heads, feet (of poultry), partially defatted fatty tissue, stomach and intestines emptied of their contents. It does not include hair, horns, teeth or hooves. Depending on the supplier and the type of refining process that the manufacturer uses, by-products can vary greatly in the amount of non-digestible material they contain. The ash content can give you an idea of the quality of the by-products. High ash content is an indicator of a poorer quality protein with lesser digestibility. The presence of by-products does not indicate a poor quality diet, a higher ash to protein ratio would. Feeding trials evaluating nutrient content and digestibility will help greatly in evaluating the quality of the ingredients. This information is available in most product reference guides, on-line references and by contacting the manufacturer. Knowing the reputation of the manufacturer is your best indicator of a good quality diet.
MYTH: Feeding trials are not necessary...Feeding trial protocol as established by the AAFCO for adult maintenance lasts 6 months, requires only 8 animals per group and monitors a limited number of parameters. These parameters are set at the minimum nutrient requirements as defined by the National Research Council. These levels tend to be lower than the recommended daily intake (RDI). Requirements are the minimum level of a nutrient, which over time, is sufficient to maintain the desired physiological functions of the animals in the population. RDI is the level of intake of a nutrient that appears to be adequate to meet known nutritional needs of practically all healthy individuals. The National Research Council recommendations are to serve as a guide to diet formulations, but they do not account for digestibility or nutrient availability. AAFCO feeding trials provide reasonable assurance of nutrient availability and sufficient palatability to ensure acceptability. They also provide some assurance that the product will support certain functions such as gestation, lactation and growth. A feeding trial is also the only way to accurately access the quality of the protein in a diet, as this is the only valid way to determine digestibility of a protein, and therefore its quality. Passing a feeding trial does not ensure that the food will be effective in preventing long-term nutrition/health problems or detect problems with a low prevalence in the general population. A feeding trial is also not designed to ensure optimal growth or maximize physical activity. If a diet has not gone through a feeding trial by the manufacturer, you will be conducting the feeding trial for them using your patients and pets. While feeding trials especially on therapeutic diets cannot be expected to detect all deficiencies or excesses (which may also be due to malabsorption or maldigestion) they give you an added advantage of having someone else evaluate them before you offer them to your clients. Feeding trials are conducted on healthy dogs and cats, with controls that are the same breed and gender. During the trials, the animals must receive the test food as their only source of nutrition. The same formula must be fed throughout the entire trial. The trials are conducted by measuring the daily food consumption, weekly body weight measurement, stated lab parameters measured at the end of the trial, complete physical exam by a veterinarian at the beginning and end of the trial, a number of animals, not to exceed 25% can be removed for non-nutritional reasons or poor food intake, necropsy conducted on any animal which dies during the trial with findings recorded, reproducing animals need the additional following information recorded, body weight within 24 hours of delivery, offspring's body weight within 24 hours of birth, litter size at birth, 1 day later and at end of study, any stillborn or congenital abnormalities.
At the end of the feeding trial, the results obtained are compared to the results from a control group, a historical colony average or to reference values published by the AAFCO.
All premium manufacturers conduct feeding trials on their foods, and continue to conduct them as the foods are changed and updated both for palatability and as new evidence is discovered regarding nutritional requirements. To verify if feeding trails have been conducted on a food, check the product label to find the source of AAFCO certification, if feeding trials have been done, it will be stated on the label as such.