Hoofdstuk 6 nutrition and experimental results
The health status, performance and metabolism of experimental animals are influenced by the
composition of the diet and the feeding practice. It will thus also affect the outcome of
experiments. Even unintentionally.example if food intake of control and experimental group not
the same is.
Nutrient requirements
> ensuring the presence of all the essential nutrients in the required concentrations!
Criteria:
Growth, reproduction, nutrient storage, enzyme activity and morphological and histological
characteristics are taken into account.
Mostly minimal requirement is used: the lowest amount of a given nutrient which can be present
without showing signs of deficiency, or to the maintenance of normal level of certain metabolites
in the blood or urine.
> related to the criterion which was used when it was established
> maximum growth is often used as the criterion for determining the recommended requirements
for laboratory animals. (this can have negative influence on health)
Types of laboratory animal diets:
- Natural ingredients diets (with oats, corn, soja.. Can vary! Most used.
- Chemically defined diet (with pure chemicals, amino acids ipv whole proteins. Expensive,
fixed values but in factory can change due oxidation etc)
- Purified diets (combination of natural ingredients, pure chemicals and ingredient of
varying degree of refinements. Inexpensive, more stable than chemical . sterilized feed
etc)
Variation in diet composition
Variation can lead to clinical signs of deficiency or toxicity. Will occur frequently and not often
obvious.> nevertheless can influence the outcome.
Two types of diet variation
- One being differences occurring between diets from different manufacturers
- Where differences occur between batches of one particular brand
Researchers should not choose a brand of commercial diet purely on the basis of catalogue
values, since such values generally do not conform with chemical analyses
Impact of variation in diet composition
A variable diet induced bias of experimental results implies that the results of different
experiments are not comparable, this will increase the need to repeat the experiment
Diet standardization
Clearly a standard diet for rats (or other animals) does not exist
When using natural ingredient it is not possible to produce a standard diet, even with purified
ingredient not
Practical approaches to diet variation
The health status, performance and metabolism of experimental animals are influenced by the
composition of the diet and the feeding practice. It will thus also affect the outcome of
experiments. Even unintentionally.example if food intake of control and experimental group not
the same is.
Nutrient requirements
> ensuring the presence of all the essential nutrients in the required concentrations!
Criteria:
Growth, reproduction, nutrient storage, enzyme activity and morphological and histological
characteristics are taken into account.
Mostly minimal requirement is used: the lowest amount of a given nutrient which can be present
without showing signs of deficiency, or to the maintenance of normal level of certain metabolites
in the blood or urine.
> related to the criterion which was used when it was established
> maximum growth is often used as the criterion for determining the recommended requirements
for laboratory animals. (this can have negative influence on health)
Types of laboratory animal diets:
- Natural ingredients diets (with oats, corn, soja.. Can vary! Most used.
- Chemically defined diet (with pure chemicals, amino acids ipv whole proteins. Expensive,
fixed values but in factory can change due oxidation etc)
- Purified diets (combination of natural ingredients, pure chemicals and ingredient of
varying degree of refinements. Inexpensive, more stable than chemical . sterilized feed
etc)
Variation in diet composition
Variation can lead to clinical signs of deficiency or toxicity. Will occur frequently and not often
obvious.> nevertheless can influence the outcome.
Two types of diet variation
- One being differences occurring between diets from different manufacturers
- Where differences occur between batches of one particular brand
Researchers should not choose a brand of commercial diet purely on the basis of catalogue
values, since such values generally do not conform with chemical analyses
Impact of variation in diet composition
A variable diet induced bias of experimental results implies that the results of different
experiments are not comparable, this will increase the need to repeat the experiment
Diet standardization
Clearly a standard diet for rats (or other animals) does not exist
When using natural ingredient it is not possible to produce a standard diet, even with purified
ingredient not
Practical approaches to diet variation
