Clostridioides difficile toxin A-mediated Caco-2 cell barrier damage was attenuated by insect-derived fractions and corresponded to increased gene transcription of cell junctional and proliferation proteins.

Pathogenesis of C. difficile in the intestine is associated with the secretion of toxins which can damage the intestinal epithelial layer and result in diseases such as diarrhoea. Treatment for C. difficile infections consists of antibiotics which, however, have non-specific microbiocidal effects and may cause intestinal dysbiosis which results in subsequent health issues. Therefore, alternative treatments to C. difficile infections are required. We investigated whether different black soldier fly- and mealworm-derived fractions, after applying the INFOGEST digestion protocol, could counteract C. difficile toxin A-mediated barrier damage of small intestinal Caco-2 cells. Treatment and pre-treatment with insect-derived fractions significantly (p < 0.05) mitigated the decrease of the transepithelial electrical resistance (TEER) of Caco-2 cells induced by C. difficile toxin A. In relation to these effects, RNA sequencing data showed an increased transcription of cell junctional and proliferation protein genes in Caco-2 cells. Furthermore, the transcription of genes regulating immune signalling was also increased. To identify whether this resulted in immune activation we used a Caco-2/THP-1 co-culture model where the cells were only separated by a permeable membrane. However, the insect-derived fractions did not change the basolateral secreted IL-8 levels in this model. To conclude, our findings suggest that black soldier fly- and mealworm-derived fractions can attenuate C. difficile induced intestinal barrier disruption and they might be promising tools to reduce the symptoms of C. difficile infections.

Supplementation of pomegranate processing waste and waste soybean cooking oil as an alternative feed resource with vitamin E in broiler nutrition: effects on productive performance, meat quality and meat fatty acid composition.

This research aimed to determine the effect of dietary supplementation of pomegranate peels powder and waste soybean cooking oil on the performance and meat quality of male Ross 308 broiler chickens. Before start of the experiment, the metabolisable energy of pomegranate peels and other nutritive and chemical contents of pomegranate peels were measured. Also, peroxidation indices and fatty acids profiles of experimental oils were analysed. The experiment was designed as a 3 × 3 × 2 factorial arrangement of treatments including i) pomegranate peels (0, 4 and 8%), ii) waste soybean cooking oil (0, 2 and 4%) and iii) vitamin E (0 and 200 mg/kg diet). Supplementation of 8% pomegranate peels significantly decreased growth performance of broiler chickens (p < 0.05). The supplementation of 4% waste cooking oil significantly reduced body weight gain during the grower and whole experimental period (p < 0.05). Pomegranate peels supplementation decreased peroxide value (PV) and thiobarbituric acid (TBA) and increased pH of meat (p < 0.05). Supplementation of 4% waste cooking oil increased PV and TBA and reduced crude protein, water holding capacity (WHC), and pH of meat (p < 0.05). Vitamin E supplementation significantly decreased TBA and increased WHC of meat (p < 0.05). Supplementation of pomegranate peels decreased saturated fatty acids (SFA) and increased polyunsaturated fatty acids (PUFA) of meat (p < 0.05). Broilers fed diets with 4% waste cooking oil showed higher SFA and lower PUFA contents in meat (p < 0.05). So it can be concluded that 4% pomegranate peels could be used as an alternative feed ingredient and a source of antioxidants in broiler diets, and also 2% waste soybean cooking oil can be included as feed ingredient in broiler diets without adversely affecting performance.