Replacing cereal with ultra-processed foods in pig diets does not adverse gut microbiota, L-glutamate uptake, or serum insulin

Background Using ultra-processed food (UPF) to replace traditional feed ingredients offers a promising strategy for enhancing food production sustainability. Objective Analyze the impact of salty and sugary UPF on gut microbiota, amino acids uptake, and serum analytes in growing and finishing pig. Methods Thirty-six Swiss Large White male castrated pigs were assigned to three experimental diets: (1) standard (ST), 0% UPF; (2) 30% conventional ingredients replaced by sugary UPF (SU); and (3) 30% conventional ingredients replaced by salty UPF (SA). The Next Generation Sequencing was used to characterise the fecal microbiota. Trans-epithelial electrical resistance (TEER) and the active uptake of selected amino acids in pig jejuna were also evaluated. Data were enriched with measurements of fecal volatile fatty acids and serum urea, minerals and insulin. All data analyses were run in R v4.0.3. The packages phyloseq, vegan, microbiome and microbiomeutilities were used for microbiota data analysis. The remaining data were analyzed by ANOVA using linear mixed-effects regression models. Results The UPF did not affect fecal microbiota abundance or biodiversity. The Firmicutes to Bacteroidetes ratio remained unaffected. SU-induced increase in the Anaerostipes genus suggested altered glucose metabolism, while SA increased the abundance of CAG-352 and p-2534-18B. No effects on fecal volatile fatty acids were observed. Assumptions of UPF negatively affecting small intestinal physiology were not supported by the measurements of TEER in pigs. Active amino acids uptake tests showed potential decrease in L-glutamate absorption in the SA compared to the SU diet. Blood serum analysis indicated no adverse effects on urea, calcium, magnesium or potassium concentration but the SU group resulted in a lower blood serum insulin level at the time of blood collection. Conclusions When incorporated at 30% into a standard growing-finishing diet for pigs, UPF does not have detrimental effects on gut microbiota, intestinal integrity and blood mineral homeostasis.