Thiamin deficiency in cats and dogs associated with feeding meat preserved with sulphur dioxide

Impact of concerning excipients on animal safety: insights for veterinary pharmacotherapy and regulatory considerations

OBJECTIVES

Veterinarians and pharmacists are familiar with the efficacy and safety aspects attributed to active pharmaceutical ingredients included in medicines, but they are rarely concerned with the safety of excipients present in medicines. Although generally recognized as safe, excipients are not chemically inert and may produce adverse events in certain animal populations. This review aims to present excipients of concern to these populations and highlight their relevance for rational veterinary pharmacotherapy.

EVIDENCE ACQUISITION

A comprehensive review of the literature about the existence of adverse reactions in animals caused by pharmaceutical excipients was carried out based on an exploratory study. An overview of the correct conditions of use and safety of these excipients has also been provided, with information about their function, the proportion in which they are included in the different pharmaceutical dosage forms and the usual routes of administration.

RESULTS

We identified 18 excipients considered of concern due to their potential to cause harm to the health of specific animal populations: bentonite, benzalkonium chloride, benzoic acid, benzyl alcohol, ethanol, lactose, mannitol, mineral oil, monosodium glutamate, polyethylene glycol, polysorbate, propylene glycol, sodium benzoate, sodium carboxymethylcellulose, sodium lauryl sulfate, sulfites, polyoxyethylene castor oil derivatives, and xylitol. Among the 135 manuscripts listed, only 24 referred to studies in which the substances were correctly evaluated as excipients.

CONCLUSIONS

Based on the information presented in this review, the authors hope to draw the attention of professionals involved in veterinary pharmacotherapy to the existence of excipients of concern in medicines. This information contributes to rational veterinary pharmacotherapy and supports veterinary pharmacovigilance actions. We hope to shed light on the subject and encourage studies and new manuscripts that address the safety of pharmaceutical excipients to the animal population.

Thiamine deficiency in a dog associated with exclusive consumption of boiled sweet potato (Ipomoea batatas): Serial changes in clinical findings, magnetic resonance imaging findings and blood lactate and thiamine concentrations

Thiamine (vitamin B₁) is an essential nutrient that significantly influences ATP production in the body. It needs to be supplemented consistently through an exogenous source to prevent deficiency; however, it is easily affected by a variety of mitigating factors. Additionally, thiamine requirements can be influenced by an individual's dietary composition. The nervous system is particularly vulnerable to thiamine deficiency due to its high metabolic demand. Thiamine deficiency is typically diagnosed based on clinical signs, dietary history and response to thiamine administration. A 5‐year‐old neutered male Maltese Terrier dog presented with an acute onset of seizures and generalized ataxia. The dog was exclusively fed boiled sweet potato (Ipomoea batatas) as a primary diet source for 4 weeks. MR findings and hyperlactatemic conditions were consistent with thiamine deficiency, and the diagnosis was confirmed by measuring thiamine concentrations in blood using high‐performance liquid chromatography (HPLC). Appropriate thiamine supplementation and diet changes resulted in a rapid improvement in neurological signs. Repeated MR imaging 2 weeks after starting the treatment completely resolved the previously identified abnormalities, and repeated measurements of blood lactate and thiamine levels revealed complete recovery of the thiamine‐deficient status.

Partial replacement of dietary buffalo meat on the bone with chicken carcass improves serum antioxidant profile of zoo-housed Indian leopards (Panthera pardus fusca)

This experiment was conducted to study the effect of gradual replacement of dietary buffalo meat on the bone (BMB) with chicken carcass (CC) on nutrient utilization, serum cortisol, and total serum antioxidant profile of zoo-housed Indian leopard. Twelve adult leopards were randomly distributed into a replicated Latin square design comprising three treatments, three periods, four animals, and three sequences. Leopards in group T₁ were fed normal zoo diet of BMB. On the basis of dry matter, 10% and 20% of BMB was replaced with CC in groups T₂ and T₃ , respectively. Each experimental period comprised 21 days. During each period, a digestion trial of 4-day collection period was conducted after an adaptation period of 17 days. On Day 21 of each experimental period, blood was collected from all the animals by puncturing the ventral coccygial vein. Intake and apparent digestibility of major nutrients were similar among the groups. Replacement of 20% BMB with addition of CC increased (p < 0.001) the calculated supply of I, niacin, and vitamin A. Carotenoid intake increased (p < 0.01) with increased level of CC in the diet. Serum concentration of cortisol decreased (p < 0.01) whereas serum concentration of total carotenoids increased (p < 0.001) with increased level of CC in the diet. Serum concentration of antioxidant enzymes increased (p < 0.001) with increased level of CC in the diet. It was concluded that replacement of 20% of BMB with CC increased antioxidant profile. This may reduce oxidative stress in zoo-housed Indian leopards without any adverse effect on nutrient utilization.

Clinical use of plasma lactate concentration. Part 1: Physiology, pathophysiology, and measurement

OBJECTIVE

To review the current literature with respect to the physiology, pathophysiology, and measurement of lactate.

DATA SOURCES

Data were sourced from veterinary and human clinical trials, retrospective studies, experimental studies, and review articles. Articles were retrieved without date restrictions and were sourced primarily via PubMed, Scopus, and CAB Abstracts as well as by manual selection.

HUMAN AND VETERINARY DATA SYNTHESIS

Lactate is an important energy storage molecule, the production of which preserves cellular energy production and mitigates the acidosis from ATP hydrolysis. Although the most common cause of hyperlactatemia is inadequate tissue oxygen delivery, hyperlactatemia can, and does occur in the face of apparently adequate oxygen supply. At a cellular level, the pathogenesis of hyperlactatemia varies widely depending on the underlying cause. Microcirculatory dysfunction, mitochondrial dysfunction, and epinephrine-mediated stimulation of Na⁺ -K⁺ -ATPase pumps are likely important contributors to hyperlactatemia in critically ill patients. Ultimately, hyperlactatemia is a marker of altered cellular bioenergetics.

CONCLUSION

The etiology of hyperlactatemia is complex and multifactorial. Understanding the relevant pathophysiology is helpful when characterizing hyperlactatemia in clinical patients.

The Role of Thiamine and Effects of Deficiency in Dogs and Cats

Recent pet food recalls for insufficient dietary thiamine have highlighted the importance of adequate thiamine intake in dogs and cats, as thiamine is an essential dietary nutrient with a critical role in energy metabolism. Prolonged thiamine deficiency leads to clinical signs that can span several organ systems, and deficiency can be fatal if not reversed. In this review, the current knowledge of thiamine metabolism will be summarized. Dietary recommendations for dogs and cats will be discussed, and the risk factors and clinical signs associated with thiamine deficiency will be examined.

Pre- and post-weaning diet alters the faecal metagenome in the cat with differences in vitamin and carbohydrate metabolism gene abundances

Dietary format, and its role in pet nutrition, is of interest to pet food manufacturers and pet owners alike. The aim of the present study was to investigate the effects of pre- and post-weaning diets (kibbled or canned) on the composition and function of faecal microbiota in the domestic cat by shotgun metagenomic sequencing and gene taxonomic and functional assignment using MG-RAST. Post-weaning diet had a dramatic effect on community composition; 147 of the 195 bacterial species identified had significantly different mean relative abundances between kittens fed kibbled and canned diets. The kittens fed kibbled diets had relatively higher abundances of Lactobacillus (>100-fold), Bifidobacterium (>100-fold), and Collinsella (>9-fold) than kittens fed canned diets. There were relatively few differences in the predicted microbiome functions associated with the pre-weaning diet. Post-weaning diet affected the abundance of functional gene groups. Genes involved in vitamin biosynthesis, metabolism, and transport, were significantly enriched in the metagenomes of kittens fed the canned diet. The impact of post-weaning diet on the metagenome in terms of vitamin biosynthesis functions suggests that modulation of the microbiome function through diet may be an important avenue for improving the nutrition of companion animals.

Outbreak of thiamine deficiency in cats associated with the feeding of defective dry food

Objectives

The objective of this study was to determine disease progression, association between neurological signs and magnetic resonance imaging (MRI) findings, and long-term outcome in feline thiamine deficiency associated with defective dry food.

Methods

The clinical records of 17 cats diagnosed with thiamine deficiency related to a defective dry food were examined and data collected. The thiamine level in the food was analysed by liquid chromatography–tandem mass spectrometry.

Results

The thiamine level in the food was below the recommendation of the National Research Council. Fifteen cats were fed the food exclusively. Prior to the acute development of neurological signs, most cats displayed non-specific signs such as anorexia, lethargy or vomiting. Vestibular signs of varying severity were observed in 94% of the cats, and all but one of these presented with bilateral dysfunction. Other main neurological signs included altered mentation (76%), blindness (59%) and seizures (59%). Moreover, 80% of the cats with seizures presented with cluster seizures or status epilepticus. MRI abnormalities consistent with findings reported in the previous literature were detected in five cases. MRI was unremarkable in one cat with ongoing severe neurological signs even though thiamine had been administered. Most surviving cats recovered rapidly within 2 weeks of treatment and had either returned to normal or had minimal neurological signs at the 2 month follow-up. One cat recovered slowly over 6 months. Most cats with seizures in the initial stage of the disease remained seizure free at the 24 month follow-up.

Conclusions and relevance

This study documented the association between feline thiamine deficiency and defective dry food. MRI examination provided valuable information in the diagnosis. However, normal MRI findings do not exclude the diagnosis of feline thiamine deficiency, especially once thiamine has been supplemented. MRI findings also may not always reflect the neurological status or severity. If treated promptly, most cats will recover rapidly with a good outcome. Occasionally, recovery may be slow and take several months.

Pet food recalls and pet food contaminants in small animals

Most pet foods are safe, but incidents of chemical contamination occur and lead to illness and recalls. There were 11 major pet food recalls in the United States between 1996 and 2010 that were due to chemical contaminants or misformulations: 3 aflatoxin, 3 excess vitamin D3, 1 excess methionine, 3 inadequate thiamine, and 1 adulteration with melamine and related compounds and an additional 2 warnings concerning a Fanconilike renal syndrome in dogs after ingesting large amounts of chicken jerky treat products. This article describes clinical findings and treatment of animals exposed to the most common pet food contaminants.

Feline Cerebrovascular Disease: Clinical and Histopathologic Findings in 16 Cats

Sixteen cats with cerebrovascular disease confirmed via histology to be of nontraumatic and nonneoplastic origins are described. In addition, the anatomy of the arterial supply of the cat's brain is reviewed. It is suggested that this unique arterial design may influence the incidence of cerebrovascular accidents in this species. Of the 16 cats reviewed, seven cats had ischemic infarctions, five had hemorrhagic infarctions, and four were diagnosed with intracranial hemorrhage. The median age was 8 yr and 9.5 yr in cats with infarctions and intracranial hemorrhages, respectively. Clinical signs were severe, acute, consistent with the localization of the cerebrovascular lesion, and influenced by underlying pathology. Four cats with infarction showed lateralized neurologic signs. Four cats with infarctions were diagnosed with pulmonary disease antemortem and three cats had hyperthyroidism. Cerebrospinal fluid analysis and computed tomography scans were available in two cats. None of the infarctions were grossly visible. All cats with hemorrhagic infarcts had severe liver pathology and nephritis was identified in four cats. Hypoxia was a feature in four cats and one cat suffered cardiac failure. In conclusion, the clinical picture is influenced by the type of cerebrovascular disease, the localization of the intracranial lesions, and any underlying pathology.

Thiamine deficiency in a cat: resolution of MRI abnormalities following thiamine supplementation

Thiamine (vitamin B₁) is an essential component of a number of metabolic pathways and thiamine deficiency results in a progressive encephalopathy in both humans and animals. Confirming thiamine deficiency is problematic and relies on demonstrating reduced red blood cells transketolase activity, or indirect methods including urinary organic acid analysis and dietary analysis. The characteristic and selective vulnerability of different brain regions in carnivores has been demonstrated by magnetic resonance (MR) imaging in the dog and cat as an aid to diagnosis. A 2-year-old, female, domestic shorthair cat was presented with an acute onset of seizures and ataxia. MR imaging was consistent with thiamine deficiency and supplementation resulted in a progressive clinical improvement. Repeated MR imaging 4 days after starting thiamine supplementation revealed near complete resolution of the MR abnormalities. Repeated MR imaging following appropriate therapy may be useful to further confirm thiamine deficiency.

Thiamine deficiency in dogs due to the feeding of sulphite preserved meat

A 6-year-old dog, a 4-year-old dog and three 7-week-old puppies were diagnosed with thiamine deficiency caused by feeding sulphite treated meat. The 6-year-old dog presented with a history of inappetence, weight loss and vomiting that rapidly progressed to signs of multifocal intracranial disease including mental dullness, paresis, seizures, spontaneous nystagmus and strabismus. Thiamine pyrophosphate effect was elevated at 58% and magnetic resonance imaging revealed bilaterally symmetrical hyperintensity of the caudate nucleus and rostral colliculi. The dog recovered with thiamine supplementation. The 4-year-old dog and three 7-week-old puppies also presented with rapidly progressive multifocal central nervous system signs including ataxia, paresis, increased muscle tone, seizures, nystagmus and exophthalmos. The 4-year-old dog made a rapid recovery with thiamine supplementation. Euthanasia and necropsy of a puppy revealed malacia of multiple brainstem nuclei and oedema of the cerebral cortex. These findings were consistent with thiamine deficiency.

Thiamine deficiency in a cat associated with the preservation of 'pet meat' with sulphur dioxide

A cat with allergic dermatitis was fed a diet of fresh meat and a multi-vitamin supplement for 38 days to exclude food allergy as a cause of its dermatopathy. The cat died as a result of acute thiamine deficiency, which was caused by inactivation of thiamine by the preservative, sulphur dioxide. The continuing undeclared usage of sulphites in the Australian pet food industry is discussed.