In vivo assay citrus pulp weaned piglets

Functional ingredients rich in dietary fibres are potential levers to prevent gut disorders in piglets and to enhance intestinal health at weaning. In particular, feed by-products from the agro-industrial sector have gained interest for their availability at affordable prices. In the current trial, 128 male weaned piglets of 21 days of age were assigned to a randomised complete block design with 32 pens of four piglets each. Following a five-day adaptation period with a creep feed diet, they were assigned to four treatments, i.e. control, inulin supplemented at 0.2 % (IN) and citrus pulp supplemented either at 0.2 % (CP0.2 %) or at 2 % (CP2 %). In this study, the IN and control treatments were considered as positive and negative controls, respectively. On d10-11 and d31-32 of the experiment, one piglet per pen was euthanized for intestinal content collection in order to evaluate the effects of IN, CP0.2 % and CP2 % on pH values, on ileal, caecal and colonic metabolite profiles and on colonic microbial populations in the early and late post-weaning periods. Metabolite and microbiota profiles were analysed by high performance liquid chromatography and 16S rRNA sequencing, respectively. Ileal, caecal and colonic pH values remained unaffected by the inclusion of both concentrations of CP as well as IN, regardless of the sampling time. Increased colonic acetate proportions on d10-11, at the expense of branched-chain fatty acid levels were observed following CP2 % supplementation compared to the control diet, suggesting a reduction of proteolytic fermentation in the hindgut of newly weaned piglets. Two beneficial health-related microbial communities, i.e. Faecalibacterium spp. and Lachnospira spp. were promoted in the colon of piglets fed with CP2 % both on d10-11 and on d31-32 of the experiment. The relative abundance in Megasphaera spp. genus was also increased under CP2 % treatment but only at the second sampling time. Conversely to CP2 %, supplementation with IN or CP0.2 % only showed mild effects on metabolite and microbiota profiles compared to the control feed, inferring a dose-dependent effect of citrus pulp. Citrus pulp, supplemented at 2 %, could therefore be an effective candidate for future inclusion in the piglet’s diet to modulate hindgut fermentation for health purposes at weaning.