Fermented Rapeseed Meal as a Component of the Mink Diet (Neovison vison) Modulating the Gastrointestinal Tract Microbiota

SIMPLE SUMMARY: The high protein requirement in the diet of mink is currently met using extruded cereals, meat and bone meal, which raises the cost of mink farming. At the same time, there are waste products that may contain many infectious agents. Therefore, there is a need to look for high-protein feeds with properties stabilizing the gastrointestinal tract (GIT). Fermented rapeseed meal (FRSM) may prove to be such a material. During the fermentation process, rapeseed loses the anti-nutritional substances contained in it, while acquiring new properties of a bioproduct. A study was carried out in mink to determine how FRSM in the diet modifies the population of microorganisms inhabiting the GIT and stabilizes its microbiota. FRSM was included in the feed of experimental animals, and changes in the population size of groups of intestinal microorganisms were analysed in relation to the control group receiving standard feed. Microbiological analyses were performed on faeces samples and from intestinal contents collected after the animals had been euthanized. The paper presents the effect of supplementation with FRSM obtained using biotechnological methods and demonstrates that it can be used in animal diets as a bioproduct influencing the gastrointestinal microbiota. ABSTRACT: Fermented rapeseed meal (FRSM) was used in the diet of American mink (Neovison vison). An advantage of this product is its prebiotic and functional properties, which can modify the bacterial microbiota of the GIT. A control group and three experimental groups were formed, with 60 animals in each group. The control group received a basal diet and the experimental groups received a diet with a 2%, 4% or 6% of FRSM as a replacement of extruded wheat. Bacillus subtilis strain 87Y was used to ferment the rapeseed meal (RSM). The study was conducted on mink from the age of 16–17 weeks until slaughter. Changes in the microbiota were analysed in samples of the animals’ faeces and intestinal contents. The analyses included determination of the total number of bacteria and fungi, the number of coliforms and Escherichia coli, the total number of anaerobic Clostridium perfringens, and the presence of Salmonella spp. In animals receiving 4% and 6% FRSM (groups II and III), the content of microscopic fungi and the number of C. perfringens bacteria was significantly (p ≤ 0.05) lower than in the animals from the control group (group 0). A decrease in E. coli was observed in all experimental groups (I, II and III), although these differences were not statistically significant. The inclusion of FRSM in the feed ration did not affect the number of lactic acid intestinal bacteria. Analysis of the results obtained from the stool samples showed that the inclusion of FRSM in the ration did not significantly affect the number of microorganisms in each group. However, as in the case of the intestinal contents, in these samples there was a decrease in the total number of C. perfringens in the experimental groups (I, II and III), with a simultaneous increase in the number of mesophilic bacteria in relation to the control. There was no detection of Salmonella bacteria in any of the analysed material.