Therapeutic Effectiveness of a Dietary Supplement for Management of Halitosis in Dogs

Halitosis is a common problem in dogs, representing a psychosocial issue significantly affecting the pet-owner relationship¹⁹. Bad breath comes from microbial metabolism of both exogenous and endogenous protein substrates within the oral cavity²⁰ which results in volatile sulphur compound production, and is worsened by other factors including acute necrotising ulcerative gingivitis, infected extraction site, debris under dental appliances, ulcers, tonsilloliths and low hygiene^21-23. The main agents responsible for bad breath production are Gram-negative bacteria²⁴ and their increase is related to a thickening of dental plaque²⁵. Good oral hygiene along with specific diets can reduce the microbial load to the physiological level, reducing halitosis and avoiding gengivitis and periodontal diseases that have unpleasant effects on breath²⁶.

This view is supported by our study showing that, after 10 days of dietary supplement intake, an overall improvement was observed in 29 out of 32 dogs (90%) presenting a moderateto-severe malodor and, at the end of the evaluation, 19 out of 29 dogs (65%) who achieved an improvement acquired a stabile physiological condition regarding VSCs concentration.

Our investigation broaches the very intriguing issue of the possible administration of a dietary supplement to dogs with breath malodor by basically introducing fish hydrolized proteins, sage, Ribes nigrum L., thyme, lysozyme, propolis, bioflavonoids and vitamin C in the daily nutritional schedule. These compounds, widely used in traditional medicine, have been already proven effective both in vitro and in vivo.

Specifically, fish proteins were chosen on the basis of previous chromatographic studies which pointed out the presence of great amounts of hydrogen sulfide, methanethiol, ethanethiol, dimethyl sulfide, and ethylene sulfide in beef proteins²⁷. Literature studies have also shown an antimicrobial activity of sage and Ribes nigrum L. against Streptoccocus mutans which is known to be one of the oral pathogens (along with Porphyromonas gingivalis and Candida albicans) responsible for oral malodor and dental caries formation^28-30. Bioflavonoids and vitamin C have been recognized as both antiinflammatory and bacteriostatic agents limiting the growth of certain bacteria associated with periodontal diseases³¹.

Regarding propolis and thyme, a reduction in malodor production from incubated whole saliva was demonstrated by Sterer et al.³² The bacteriostatic activity of propolis has been widely demontrated in literature, ranging from limiting the quantity of bacterial plaque^33-37 to decreasing the tolerance of microorganisms to acid pH³⁸, showing greater effectiveness than chlorhexidine gluconate solutions³⁹. Moreover, propolis was proven effective in reducing teeth caries in rats limiting the number of microorganisms, slowing down synthesis of insoluble glucans, and glucosyltransferase activity⁴⁰.

Our study presents some limitations such as the sensitivity of the instrument, if compared with other available techniques (e.g. bumpy WO3 hemitube nanostructure assisted by O₂ plasma surface modification with functionalization of graphene-based material⁴¹, electrospun SnO₂ nanofibers sensitized with reduced graphene oxide nanosheets⁴², benzoyl-DL-arginine-naphthylamide (BANA) test⁴³, High Performance Liquid Chromatography (HPLC)⁴⁴ and Solid-Phase Micro Extraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS⁴⁵). On the other hand, the device employed in this study might allow, for instance, fast data collection to rapidly achieve an early diagnosis of viral hepatitis B, which is also characterized by elevated dimethile sulfide levels⁴⁶ or to establish a state of systemic and/or respiratory disease (such as pneumonia, pulmonary emphysema and bronchitis) that are characterized by elevated hydrogen sulfide, methyl mercaptan and dimethyl sulfide levels⁴⁷.

During the procedure we realized that the time available to collect the breath from a dog’s mouth was slightly lower than that required (few seconds against 30 sec suggested by the manufacturer). This problem was successfully overcome by repeating each measurement three times. A critical step during the experiment was breath collection. In order not to leave the dog with his mouth open for too long without damaging the syringe, we placed the syringe in the dog’s labial commissure in order to safely collect the breath.

As observed in humans, further applications of this technique will be the prevention of breath-related diseases, i.e. systemic and respiratory, in dogs and more generally in pets. In summary, our study showed that the dietary supplement was effective in reducing chronic halitosis in dogs. Our results might be also in agreement with what is proposed by Porter et al., who hypothesized a possible interplay between halitosis and the gastrointestinal tract suggesting that a therapy for halitosis with oral origin might also have some effect upon gut bacteria composition which is known to be responsible, in some cases, for volatile sulphur compounds production⁴⁸. Nevertheless, a dysbiosis might also occur after a massive use of antibiotics⁴⁹, or meat derived from intensive livestocks and commonly used in most of animal and human food^50,51.