Nitrite poisoning in cats and dogs fed a commercial pet food

Worth, Ann; Ainsworth, Sophie Jane; Brocklehurst, Peter; Collett, M.G.

doi:10.1080/00480169.1997.36025

Cited by 15 publications

(6 citation statements)

References 8 publications

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“…In cats, acute toxicosis with death due to extensive methaemoglobin formation has been reported in three animals fed on a canned feed containing on average 2,850 mg /kg nitrite (Worth et al, 1997). No effects on the growth rate or on the weight of important organs were noted in one cat receiving 105 mg/kg b.w.…”

Section: Cats and Dogsmentioning

confidence: 96%

Nitrite as undesirable substances in animal feed ‐ Scientific Opinion of the Panel on Contaminants in the Food Chain

2009

EFS2

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SUMMARYNitrite is formed naturally by the nitrogen cycle during the process of nitrogen fixation and it is subsequently converted to nitrate, a major nutrient assimilated by plants. Two main nitrite salt forms occur, namely sodium and potassium nitrite.In animal tissues, nitrite is naturally present mainly as the result of endogenous nitrate conversion. Animal feed represents a natural source of exogenous nitrite and because of its potential for toxicity at excessive levels of intake, the Directive (EC) No 2002/32/EC on undesirable substances in animal feed established maximum limits for sodium nitrite in complete feedingstuffs excluding feedingstuffs intended for pets except birds and aquarium fish, and fish meal of 15 and 60 mg/kg, respectively (corresponding to 10 and 40 mg/kg for the nitrite ion). Nitrite in drinking water is regulated in Europe, with a maximum level of 0.5 mg/L. Nitrate levels in forages are naturally high and the inter-conversion of nitrate to nitrite is the largest contributor to nitrite exposure in food-producing animals. Dietary intake of nitrite per se results from the use of vegetable feeds and forages, fertilisers/manures or when used as an antimicrobial for preservation, for example in silage, processed pet food, and in former times fish meal. Additionally, water can be an important dietary source of nitrite via reduction of nitrate. The main analytical technique used to measure both nitrite and nitrate is colourimetry because of its sensitivity and specificity. Three member states provided analytical results on feedingstuffs and nitrite levels were below the maximum levels in all feed commodities.Acutely, nitrite is approximately ten-fold more toxic than nitrate and three main toxicological endpoints have been identified: methaemoglobin formation (in a wide range of species including man), hypertrophy of the adrenal zona glomerulosa (rats), and equivocal evidence In monogastric animals, most nitrite is formed and absorbed in the upper digestive tract. In contrast in ruminants, nitrite and nitrate is metabolised by the rumen flora. Reports of adverse effects after excessive nitrite exposure in livestock exist, and pigs and ruminants, as major food producing animals, are particularly susceptible: this is because of relatively low nitrite reductase activity and high levels of rumen conversion of exogenous nitrate to nitrite, respectively. Acknowledging diverse husbandry conditions between reported studies, NoObserved Adverse Effect Levels (NOAELs) for pigs and cattle have been estimated from the literature with a value of 3.3 mg/kg b.w. per day in both species. In turn, total daily nitrite intakes were estimated for pigs and cattle using the maximum exposure level in complete feed according to the current legislation (10 mg/kg), typical feeding regimens within the European Union and maximum nitrite level in forages from member states (cattle). Overall, the estimated nitrite intakes for pigs and cattle from feed were 0.37 and 0.65 mg/kg b.w. per day (excluding endogenous formation of n...

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Section: Cats and Dogsmentioning

confidence: 96%

Nitrite as undesirable substances in animal feed ‐ Scientific Opinion of the Panel on Contaminants in the Food Chain

2009

EFS2

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“…It is a precursor of nitrosamines, carcinogens in man and animals (Sebranek & Cassens 1972) and has been linked to death in three cats, and ataxia and weakness in two dogs (Worth et al . 1997). Its use as a preservative is more common in cat food than dog food (Table 3).…”

Section: Additives Associated With Safety Issues In Dogs and Catsmentioning

confidence: 99%

“…Sodium nitrite enhances the pink colouration of animal proteins, improves flavour, inhibits lipid oxidation and prevents the growth of botulism-forming bacteria (Kobayashi et al 2017). It is a precursor of nitrosamines, carcinogens in man and animals (Sebranek & Cassens 1972) and has been linked to death in three cats, and ataxia and weakness in two dogs (Worth et al 1997). Its use as a preservative is more common in cat food than dog food (Table 3).…”

Section: Sodium Nitritementioning

confidence: 99%

Additives in pet food: are they safe?

Craig¹

2021

J of Small Animal Practice

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A good, nutritious diet is essential for the health and well‐being of our domestic pets. Today, most pet dogs and cats are fed highly processed food bearing little resemblance to canine and feline ancestral diets. Additives are included in processed pet food to provide nutritional benefits, ensure food safety, and maintain the desirable features of colour, flavour, texture, stability and resistance to spoilage. This paper reviews the safety of various additives in processed pet food. Labelling, safety assessment, and ethical concerns regarding existing toxicity testing procedures are also considered. The adequacy of testing for many additives and the scientific basis for determining safety are questioned. Additives can be synthetic or ‘natural’ although the distinction can be blurred when naturally derived substances are synthesised in the laboratory, or extracted using a high level of physical and chemical processing. Although additives play important roles in processed food production, updated strategies and technologies may be required to establish their safety in the pet food industry.

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“…Given that cyanosis and MetHb were observed in dogs, primarily at the high dose group, the intravenous NOAEL was considered from the authors to be 9.33 mg NO 2 -/kg bw per day. In cats, acute toxicosis with death due to extensive MetHb formation has been reported in three animals fed on a canned feed containing on average 1,900 mg NO 2 -/kg canned feed (Worth et al, 1997). Lehman (1958) reported that no adverse effects were observed on growth performance and organ weight in one cat receiving an oral dose of 6.5 mg NO 2 -/kg bw per day, for a period of 105 days.…”

Section: Dogs and Catsmentioning

confidence: 99%

Risk assessment of nitrate and nitrite in feed

Schrenk¹,

Bignami²,

Bodin³

et al. 2020

EFS2

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The European Commission asked EFSA for a scientific opinion on the risks to animal health related to nitrite and nitrate in feed. For nitrate ion, the EFSA Panel on Contaminants in the Food Chain ( CONTAM Panel) identified a BMDL 10 of 64 mg nitrate/kg body weight (bw) per day for adult cattle, based on methaemoglobin (MetHb) levels in animal's blood that would not induce clinical signs of hypoxia. The BMDL 10 is applicable to all bovines, except for pregnant cows in which reproductive effects were not clearly associated with MetHb formation. Since the data available suggested that ovines and caprines are not more sensitive than bovines, the BMDL 10 could also be applied to these species. Highest mean exposure estimates of 53 and 60 mg nitrate/kg bw per day in grass silage‐based diets for beef cattle and fattening goats, respectively, may raise a health concern for ruminants when compared with the BMDL 10 of 64 mg nitrate/kg bw per day. The concern may be higher because other forages might contain higher levels of nitrate. Highest mean exposure estimates of 2.0 mg nitrate/kg bw per day in pigs’ feeds indicate a low risk for adverse health effects, when compared with an identified no observed adverse effect level ( NOAEL ) of 410 mg nitrate/kg bw per day, although the levels of exposure might be underestimated due to the absence of data on certain key ingredients in the diets of this species. Due to the limitations of the data available, the CONTAM Panel could not characterise the health risk in species other than ruminants and pigs from nitrate and in all livestock and companion animals from nitrite. Based on a limited data set, both the transfer of nitrate and nitrite from feed to food products of animal origin and the nitrate‐ and nitrite‐mediated formation of N‐nitrosamines and their transfer into these products are likely to be negligible.

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Nitrite poisoning in cats and dogs fed a commercial pet food

Cited by 15 publications

References 8 publications

Nitrite as undesirable substances in animal feed ‐ Scientific Opinion of the Panel on Contaminants in the Food Chain

Nitrite as undesirable substances in animal feed ‐ Scientific Opinion of the Panel on Contaminants in the Food Chain

Additives in pet food: are they safe?

Risk assessment of nitrate and nitrite in feed

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