Application of the E-tongue for evaluating fecal biogenic amines in dogs fed hydrolyzed feather meal

Previous studies have shown that electronic sensory technologies (E-eye, E-tongue, E-nose) can serve as effective and rapid alternatives to official analytical methods for evaluating petfood digestibility. In this study the impact of substituting 7% of poultry meal with hydrolyzed feather meal on digestive processes was investigated using the E-tongue to detect fecal biogenic amines in adult dogs. Six adult female English Setter dogs were divided into two groups and fed two different commercial kibble diets over a 45-day period. The control group (CTR) received a diet based on poultry meal as the protein source, while the treated group (TRT) was fed a diet consisting of a mix of poultry meal and hydrolyzed feather meal. A crossover experimental design was applied. Fecal samples were collected on Day 0 and after 3, 7, 15 and 45 days, and analyzed using a potentiometric E-Tongue (aAstree, Alpha MOS, Toulouse, France) equipped with seven chemical sensors. Biogenic amines were also quantified by high-performance liquid chromatography with fluorescence detection. The dataset was subjected to statistical analysis using Discriminant Function Analysis (DFA) to assess the effect of time (Days 0. 3, 7, 15, 45) for each diet, and the effect of diet (TRT vs. CTR) independently of time. Additionally, a data fusion approach was applied to validate the instrumental sensory results through quantitative identification of catabolites. using traditional chromatographic analyses. The DFA plot generated from the E-tongue sensor signals revealed a clear separation between the CTR and TRT groups, with the maximum Discrimination Index (DI = 100) on Days 0, 3, and 15, and a DI 0£ 95 on Days 7 and 45. The TRT group exhibited the highest levels of putrescine and cadaverine at all time points, while the CTR group showed the highest levels of spermine on Days 0, 3, and 45. These findings were consistent with the results obtained from chromatographic analysis. Data confirm that the E-tongue technology is a reliable and rapid alternative to traditional methods. Its application is particularly valuable for assessing the impact of dietary strategies on gastrointestinal health.