Page 175 - Raw Diet References Book 2019

Proposed Revisions Edited per Comments for 2014 Official Publication 8

and phenylalanine plus tyrosine. The CNES felt it prudent to include specific
minimums for methionine and phenylalanine because although some, or all, of the
requirement for cystine and tyrosine can be met from excess methionine and
phenylalanine, respectively, the reverse is not true. Some of the previous
recommendations for dietary concentrations of essential amino acids in the Dog Food
Nutrient Profile for Adult Maintenance (i.e., histidine, lysine, threonine and
tryptophan) were greater than the corresponding RA in the 2006 NRC and the CNES
elected to retain the previously recommended amounts for these amino acids in the
current Dog Food Nutrient Profile for Adult Maintenance.
Minimum concentrations of some essential amino acids in the Dog Food Nutrient
Profile for Growth and Reproduction were increased, usually to match the NRC RA for
growth (i.e., arginine, leucine, methionine, methionine-cystine, phenylalanine-tyrosine
and valine). Although the NRC RA for total crude protein during lactation is
essentially identical to the RA for growth (22.0% versus 22.5%), several of the RA for
essential amino acids during lactation are greater than the RA for growth. In some
cases (i.e., histidine, isoleucine, lysine, phenylalanine, and threonine) the difference
was small and the CNES elected to set the recommended amount in the Growth and
Reproduction Profile at the larger NRC RA for lactation. For other essential amino
acids (i.e., leucine and valine) the RA proposed by the NRC for lactation is
substantially more than the RA for growth, and in the case of leucine and valine the
concentrations are equal to, or greater than, the corresponding RA for the cat during
lactation, an obligate carnivore with protein requirements generally greater than those
for the dog. The NRC ad hoc committee indicated that it set the RA based on, “lowest
concentrations of each of the essential amino acids from digestible protein in
commercial dry expanded diets that have been shown to sustain normal gestation and
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lactation for bitches.” The CNES chose not to increase the recommended
concentrations for leucine and valine to those of the NRC RA for lactation based on
lack of documented problems with the previous concentrations in the AAFCO Dog
Food Nutrient Profile for Growth and Reproduction and the relative disparity in the RA
between canine versus feline protein requirements. The CNES did not elect to change
the tryptophan concentration in the Dog Food Nutrient Profile for Growth and
Reproduction for two reasons. The CNES had access to feeding studies and a
publication showing that the minimum requirement for tryptophan in Labrador
retriever puppies was less than the current concentration in AAFCO Dog Food Nutrient
Profile for Growth and Reproduction and that the tryptophan concentration of 0.2%
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DM already provided approximately a 25% safety margin. The CNES was also aware
that it was nearly impossible to formulate a product at the minimum protein
concentration to contain more than 0.2% tryptophan on a DM basis from typical
ingredients without including crystalline tryptophan in the formula.
Insufficient data were available to demonstrate detrimental effects of high protein
intake in the normal dog to allow for any definitive maximum concentrations for
protein or amino acids to be established. The CNES is aware of the findings regarding
excess lysine at some concentration between 2.0% and 4.0% lysine/kg DM to produce
depression in growth of puppies and clinical signs associated with arginine deficiency
when arginine is present at 0.4% DM, and that FEDIAF has established a concentration
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of 2.8% lysine in DM as a maximum. However, this information was available prior
to the establishment of the original AAFCO Nutrient Profiles and did not result in a
maximum lysine content being established by the 1990 Expert Subcommittee.
Furthermore, the 2007 CNES notes that the minimum recommended arginine content
for growth and reproduction is 2.5 times the concentration of 0.4% arginine/kg DM
required to produce the noted adverse effects in combination with lysine at more than
2.0%/kg DM.