My theory about the Jerky Treat Threat

Is protein the root of the problem with the Jerky Dog Treats? or Possible mulfactorial causes.

 By Marion Smart DVM, PhD Professor of Nutrition Western College of Veterinary Medicine

Introduction

The effect of dietary protein intake on renal function has been studied and reviewed extensively.[i] [ii]Although we have a better appreciation of the problem there is still much controversy surrounding the topic. This debate is related to:

·         external factors such as:

o    dietary protein quality, the source, the amino acid profile,

o    impact of heat processing, high pressure sterilization and irradiation on the protein structure, and digestibility

·         . Internal factors such as:

o   to the digestion and bioavailability of dietary protein

o    the gastrointestinal microbial utilization, metabolism and by-product production of the endogenous and exogenous protein that reaches the colon

 This paper explores the possible explanation of the illness in dogs associated with the Irradiated dehydrated Jerky treats originating from China and Thailand. The assumption being the cause is multifactorial.

The hypothesis

These jerky treats when fed to dogs on a commercial processed  diet of 30% Crude Protein  (CP)or more results  in an excess of dietary protein which the body may or may not be able to handle metabolically especially if there is some subclinical impairment of kidney and/or liver function, and an associated abnormal  gastro intestinal micro flora. This could be further complicated if the protein in the treats was heat damaged or denatured or if crude glycerine from the Biofuels industry was added as a preservative 

Asumptions:     

·         That the minimum Protein % indicated on the package label/website represents the actual protein analysis for both the treats and the dog’s daily diet.

                This assumption may be false as the true protein % is likely higher in these products than is represented on the label’s guaranteed analysis.

·         The energy requirement of a 5kg dog (model dog) was based on NRC’s 2007[iii] requirement and only applies to an inactive healthy normal adult dog with a normal body condition.

                These requirements may not represent all 5 kg adult dogs.

·         The energy density of the treats was calculated based on the protein% and fat% listed on the label or website and the calculated carbohydrate %. Atwater modified coefficients for protein of 3.5 Kcal/g of protein, 3.5 Kcal/g of carbohydrates, and 8.5 Kcals/g of fat were used in the calculations

·         Treats are not fed at more than 15% of a dog’s daily energy requirements. This is based on the information found on the Milo’s Kitchen Website. Most owners would not understand what this restriction means or how to calculate it. If they even read it. Most owners will likely over feed these treats especially if the dogs like them. They may also be feeding other high protein treats as the popular press implies that fat and     carbohydrates can lead to obesity

·         That a total dietary dry matter protein percentage of 30 % may be potentially  be metabolically inappropriate for dogs with subclinical hepatic or renal disease

·         An abnormal intestinal microbial flora (dysbiosis) may be present in these dogs

Calculations:

Table1: The calculated daily energy requirements and protein intake g/d for a normal inactive adult 5 kg dog

.  5kg Dog's  requires Kcal/d	400	% Protein in Diet 10% Moisture	25%	35%
g/d of a 400Kcal/100g Diet	100
g/protein/d			25g	35

 Table 2: The percent total protein in the diet of a 5 kg dog if the treats are limited to 5, 10, and 15% of the dog’s daily  caloric requirements, and if the protein percentages in the actual diets are  25 and35 respectively

	5% Daily Calories						10% of Daily Calories					15% of Daily Calories
	Treats				% CP in diet		Treats			% CP in Diet		Treats			% CP in Diet
	Kcal/100g	Kcal/d	g/d	g CP/d	25%	35%	Kcal/d	g/d	g CP/d	25%	35%	Kcal/d	g/d	g CP/d	25%	35%
					% Total CP	% Total CP				% Total CP	%Total CP				%Total CP	% Total CP
Vital Life Chicken Tenders	275	20	7.3	4.7	28	37	40	14.5	9.3	30.0	43.3	60	21.8	14.0	32.0	46.6
Canyon Creek Duck tenders	275		7.3	5.1	28	37		14.5	10.2	30.7	43.3		21.8	15.3	33.1	46.6
Chew Master Chicken Strips	298		6.7	4.7	28	37		13.4	9.4	30.3	42.7		20.1	14.1	32.5	45.9
Milo's Kitchen	289		6.9	4.2	27	37		13.8	8.3	29.3	42.9		20.8	12.5	31.0	46.2

Table 2 supports the fact that Jerky treats fed to dogs on diets with 35% Crude protein or greater can result in a total dietary protein intake of greater than 40% even when the treats represent   10% of the dog’s daily caloric intake.

Table 3:The total  daily  Protein intake in g/d and  % Protein  in the diet plus treats  of a 5, 10 and 20 kg dog  The caloric density of the diet is 4000Kcal/1000g. Protein requirements are between 33*(AAFCO maintenance) to 90 g/day*(ancestral diet) or 20% to 54%CP in DM. Each treat has weights approximately 12 g and provides 8.28 g of protein The optimum number of treats per day  at 15%  of daily caloric  requirements
g/day of diet  for a 5 kg  dog		100
% CP in diet		20% CP			25% CP		30% CP		35% CP		40%CP
g/d of protein		20			25		30		35		40
# Treats/day		Total CP g/d  from treats	% CP in Total Diet		Total g CP /day	% CP in Total Diet	Total g CP/day	% CP in Total Diet	Total g CP/day	% CP in Total Diet	Total g CP/day	% CP in Total Diet
1		8.28	25%		33.28	30%	38.28	34%	43.28	39%	48.28	43%
2		16.56	29%		41.56	34%	46.56	38%	51.56	42%	56.56	46%
3		24.84	33%		49.84	37%	54.84	40%	59.84	44%	64.84	48%
4		33.12	36%		58.12	39%	63.12	43%	68.12	46%	73.12	49%
5		41.4	38%		66.4	42%	71.4	45%	76.4	48%	81.4	51%
10		82.8	47%		107.8	49%	112.8	51%	117.8	54%	122.8	56%
g/day of diet for a 10 kg dog	165
%CP in Diet	20% CP				25% CP		30% CP		35%CP		40%CP
g/d of protein from diet	33				41.25		49.5		57.75		66
# Treats/day	CP g from treats		% CP in Total Diet		Total g CP in Diet	% CP in Total Diet	Total g CP in diet	% CP in Total Diet	Total g CP in diet	% CP in Total Diet	Total g CP in diet	% CP in Total Diet
1	8.28		23%		49.53	28%	57.78	33%	66.03	37%	74.28	42%
2	16.56		26%		57.81	31%	66.06	35%	74.31	39%	82.56	44%
3	24.84		29%		66.09	33%	74.34	37%	82.59	41%	90.84	45%
4	33.12		31%		74.37	35%	82.62	39%	90.87	43%	99.12	47%
5	41.4		33%		82.65	37%	90.9	40%	99.15	44%	107.4	48%
10	82.8		41%		124.05	44%	132.3	46%	140.55	49%	148.8	52%
g/day of diet for a 20kg dog	300
%CP in Diet	20% CP				25% CP		30% CP		35%CP		40%CP
g/d of protein	60				75		90		105		120
#treats/day	Total g CP/d in treats			% CP in Total Diet	Total g CP/d	% CP in Total Diet	Total g CP/d	% CP in Total Diet	Total g CP/d	% CP in Total Diet	Total g CP/d	% CP in Total Diet
1	8.28			22%	83.28	27%	98.28	32%	113.28	36%	128.28	41%
2	16.56			24%	91.56	28%	106.56	33%	121.56	38%	136.56	42%
3	24.84			25%	99.84	30%	114.84	34%	129.84	39%	144.84	43%
4	33.12			27%	108.12	31%	123.12	35%	138.12	40%	153.12	44%
5	41.4			28%	116.4	32%	131.4	37%	146.4	41%	161.4	45%
10	82.8			34%	157.8	38%	172.8	41%	187.8	45%	202.8	48%

The results in table 3 are based on the number of treats eaten per day with one treat weighing 12g and providing on average8.28 g of protein to the diet. The row in yellow represents treats fed at 15% of the total caloric requirements for that dog. .

The feeding directions on all of the treats implicated recommend so many pieces  per weight group of dog nowhere is mentioned the optimal number of grams per day that should be fed . To determine this, the pet owner would have to count the pieces in the package and then divide that number into the total weight of treats in the package...

Interpretation:

Simplistically (trying to explain a very complex system in a simple fashion), protein digestion begins in the stomach and through a coordinated series of enzymatic, hormonal and environmental (pH, electrolytes and fluids) interactions the protein is broken down into amino acids which are actively transported by a complex series of chemical reactions through the enterocytes and wall of the small intestine into the portal circulation to the liver.

Any partially digested protein, amino acids and the protein left associated with the digestive process (endogenous nitrogen loss),then  passes into the colon. The amount of dietary protein that reaches the colon is dependent on the quality of the protein (limiting amino acids, denatured protein are poorly digested), and the amount of protein ingested.  Other factors such as body weight, dietary fibre, anti-nutritive factors (inhibitors, denatured) and the composition of the colonic micro flora will influence the amount of protein and the by-products formed ^iv. The gut micro flora break down these nitrogenous compounds into ammonia, indoles, phenols, volatile sulphur containing compounds, potential neurotoxins, and many unknown and potentially toxic  compounds[iv].  Some of these compounds are absorbed into the body. Some like ammonia are metabolized in the liver and eventually excreted through the kidney as urea.  We are just beginning to appreciate the significant role these colonic microorganisms play in the body’s normal and abnormal metabolic processes[v]. Exactly how these microorganisms respond to different dietary loads, and quality of proteins is still unknown.

I believe that this may-be a plausible explanation for many of the cases, especially in the older dogs with liver and kidney pathology .In support of this theory  is that older dogs require at least 25% ⁱⁱ of their calories from protein, I was unable to find any studies were higher protein percentages were fed to normal or compromised dogs. The jerky treats may be contributing to an unbalanced or inappropriate amino acid profile in the dog’s diet. The acute cases and those seen in puppies under a year of age are more difficult to explain unless in some cases the protein is denatured or heat damaged. Some unprocessed raw diets definitely exceed 35% protein and yet they do not appear to be associated with the problem. But these diets may be providing a healthier functioning colonic microbial flora, a more balanced amino acid profile and more efficiently digested and metabolized protein.

Conclusions:

A detailed history of problems and treatments prior to and at the time of the current illness and clinical evaluation must be obtained for each dog. The clinical course of the disease and treatments need to be chronologically tabulated.  Complete laboratory findings should be charted and the hi-lite of a complete necropsy report recorded, if available, on all the dogs that died. A detailed dietary history (chronologically tabulated) is essential including the regular diet, dietary changes and all the treats fed (Name, amount, and time of Day).

References:

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[i] Finco D.R. 1999. Effects of Dietary protein Intake on renal functions. Supplement to The Compendium on Continuing  Education for the Practicing Veterinarian 21.#11:5-10

[ii] Laflame D.P.2008.  Pet Food Safety: Dietary Protein Topical Review23#3:154-157-

[iii] NRC 2007 Nutrient requirements of Dogs and cats

[iv] Savage D.C. 1986 Gastrointestinal micro flora in Mammalian Nutrition Ann. Rev Nutri 6:155-178

[v]  Oozeer R. et al 2010. Gut Health: Predictive biomarkers for preventive medicine and development of functional foods British Journal of Nutrition 103:1539-1544