Term
| What are the proximate nutrient groups ? |
|
Definition
crude fiber
crude fat
crude protein
NFE
mineral/ash
gross energy |
|
|
Term
| Rather than the proximate nutrient groups in a feed, what really matters? |
|
Definition
-individual nutrient requirements of animals
-nutrient content of the feed ingredients
-digestibility & bio-availability of nutrients
-potential limitations of ingredients e.g. anti-nutritional factors, allergenic properties |
|
|
Term
| Explain the statement "fish meal is not fish meal" |
|
Definition
| Depending on the type of fish used, the amino acid profile is different, along with the % crude protein, crude fat, ash etc. |
|
|
Term
| Why is the variability of ingredients? |
|
Definition
-processed animal protein and plant protein ingredients use different mixes of raw materials, processing equipment, conditions etc.
-different batches of the 'same' ingredient can have different nutritive value |
|
|
Term
| Why is ingredient variability a challenge in pet food production? |
|
Definition
labeling regulations are very strict, need to have detailed analysis and accurate guarantees of chemical composition
working with ingredients of variable composition makes this difficult! |
|
|
Term
| What conclusions can be made regarding the amino acid digestibility of animal by-product meals processed in different ways, in dogs & roosters? |
|
Definition
-high correlation between digestibility estimates with roosters & dogs
-amino acid digestibility varies between different meat & bone meals, poultry by-product meals
-difference in digestibility between different amino acids |
|
|
Term
| What drying technique would be the best choice for producing blood meal? Why? |
|
Definition
| spray drying, as the product has higher apparent digestibility of protein and energy |
|
|
Term
| Which is a better choice to feed to chicks, light or dark coloured DDGS, and why? |
|
Definition
light coloured
-higher lysine concentration
-growth rate, feed intake & feed conversion rates in chicks fed dark DDGS was lower
-dark DDGS have a burnt smell, perhaps less appealing? |
|
|
Term
| What is a maillard reaction? What amino acid is very sensitive to this? Why is this important |
|
Definition
a chemical reaction between amino acids and reducing sugars that gives browned foods their desirable flavor
lysine is sensitive to this
the browning reaction will reduce the amount of digestible lysine being ingested |
|
|
Term
| Why are disulfide bonds a factor to be considered |
|
Definition
they are heat stable & indigestible
-overheating of proteins can create disulfide bonds, reducing apparently digestibility of the protein |
|
|
Term
| Why would we hydrolyze feathers to produce a meal? |
|
Definition
-keratins contain many disulfide bonds, cannot digest them
-steam or enzyme hydrolysis can turn the apparent digestibility coefficient from 0% to >70% |
|
|
Term
| What are the limitations of apparent digestibility as a measure of nutritive value? |
|
Definition
-measures disappearance of nutrients, doesn't directly measure the amount of nutrient available
-heat damaged AAs may be digestible but not available |
|
|
Term
| What is slope ratio assay? |
|
Definition
response of a parameter (e.g. protein gain) to graded levels of a test ingredient, compared to the response to graded levels of a standard nutrient (e.g. a synthetic AA)
-indicates the net effect of all components that can affect bioavailability |
|
|
Term
| What are some factors affecting bioavailability? |
|
Definition
| digestion, absorption, utilization |
|
|
Term
| What are the types of rancidity that can affect lipid quality? |
|
Definition
hydrolytic rancidity
oxidative rancidity |
|
|
Term
| What is hydrolytic rancidity? Why does it cause a change in odor & flavour? What concern is this in a cat's diet? |
|
Definition
-hydrolysis of a TG into fatty acids & glycerol by lipase action
-taste of individual fatty acids is more pronounced than of total triglycerides
-cats are very sensitive to free FA level in their diet! |
|
|
Term
| What is oxidative rancidity? |
|
Definition
damage to PUFA by radicals
-it is a destructive chain reaction |
|
|
Term
| What can you use to stop or slow down the chain reaction of oxidative rancidity? |
|
Definition
|
|
Term
| What effect does a diet of oxidized fat have on dogs? |
|
Definition
-depresses growth, immune function, bone formation
- |
|
|
Term
| Why might some companies use sub-quality ingredients? |
|
Definition
| if an ingredient is not readily available, such a fish oil, turning it away upon arrival at the plant may mean you can't find a suitable substitute. |
|
|
Term
| What are the criteria for antioxidants? |
|
Definition
-effective in preserving animal & vegetable fats, vitamins & other feed qualities subject to oxidative destruction
-non toxic to animal
-effective at very low concentrations
-low enough cost to be practical |
|
|
Term
| What are some commonly used feed antioxidants? |
|
Definition
|
|
Term
| What was the issue with ethoxyquin in pet foods? |
|
Definition
-speculation/anecdotes that it caused allergies, congenital abnormalities & cancer in pets
-no concrete scientific evidence to support this, other than a connection between ethoxyquin & elevated liver enzymes (no known health effect)
-voluntarily limit to 75ppm
-most manufacturers removed from foods anyways because of public pressure |
|
|
Term
| What are some of the combined properties of various antioxidants used? |
|
Definition
-radical scavengers to remove free radicals
-chelators to reduce catalyzing effects of metal ions
-surfactants to help spread antioxidants throughout feed |
|
|
Term
| What are common natural sources of oxidants used in feeds? |
|
Definition
| rosemary oil & oregano oil |
|
|
Term
| Why do some manufacturers use natural antioxidants rather than chemically synthesized equivalents? What is the issue? |
|
Definition
-consumer demand, don't want chemically synthesized products in the food
trade off:
not as effective as chemically synthesized antioxidants
more expensive |
|
|
Term
|
Definition
-bacterial disease causing inflammation of intestines, septicemia, abortions
-caused by ingesting Salmonella (concern with raw meat esp) |
|
|
Term
| What are the two classes of contaminants that can affect feed? |
|
Definition
-inherent, naturally occurring constituent which is not due to environmental/agricultural/industrial contamination
e.g. mycotoxins, glucosinolates, lead, cadmium
-industrial substances which are not naturally occurring and increased to abnormal levels through mishandling
e.g. PCBs, pesticides like DDT |
|
|
Term
| What are some mycotoxins commonly found in feed? |
|
Definition
|
|
Term
| What animals are particularly sensitive to aflatoxins? |
|
Definition
rabbits
cats
dogs
guinea pigs |
|
|
Term
| What effects do aflatoxins have? |
|
Definition
|
|
Term
| What effect to fumonisins have? |
|
Definition
-leukoencephaloma in horses
-pulmonary edema in pigs
-carcinogenic effects |
|
|
Term
| What effect does vomitoxin have? |
|
Definition
inhibits protein synthesis
causes vomiting, weight loss |
|
|
Term
| What feed ingredient is high in melamine? |
|
Definition
|
|
Term
| What effect does melamine have? What are the symptoms? |
|
Definition
renal failure due to nitrogen toxicity
-loss of appetite
-vomiting
-excessive water consumption
-excessive urination
-lethargy
-pale yellow crystals in urine & kidneys |
|
|
