Impact of Citrus Pulp or Inulin on Intestinal Microbiota and Metabolites, Barrier, and Immune Function of Weaned Piglets

Abstract

We investigated the use of citrus pulp (CP) as a novel prebiotic capable of exerting microbiota and immunomodulating capacities to alleviate weaning stress. Inulin (IN), a well-known prebiotic, was used for comparison. Hundred and 28 male weaned piglets of 21 days old were assigned to 32 pens of 4 piglets each. Piglets were assigned to one of the four treatments, i.e., control, IN supplemented at 0.2% (IN0.2%), and CP supplemented either at 0.2% (CP0.2%) or at 2% (CP2%). On d10–11 and d31–32 post-weaning, one pig per pen was euthanized for intestinal sampling to evaluate the growth performance, chyme characteristics, small intestinal morphology, colonic inflammatory response and barrier integrity, metabolite profiles [gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS)], and microbial populations. The IN treatment and the two CP treatments induced higher small intestinal villus height to crypt depth ratios in comparison with the control diet at both sampling times. All treatments decreased acidic goblet cell absolute counts in the crypts in comparison to the control diet of the duodenum on d10–11 and d31–32. The gene expression of β-defensin 2 was downregulated in colonic tissues following the IN and CP2% inclusion on d31–32. On d31–32, piglets fed with IN and CP0.2% showed lower mRNA levels of occludin and claudin-3, respectively. Not surprisingly, flavonoids were observed in the colon in the CP treatments. Increased colonic acetate proportions on d10–11, at the expense of branched-chain fatty acid (BCFA) levels, were observed following the CP2% supplementation compared to the control diet, inferring a reduction of proteolytic fermentation in the hindgut. The beneficial microbial community Faecalibacterium spp. was promoted in the colon of piglets fed with CP2% on d10–11 (p = 0.04; false discovery rate (FDR) non-significant) and on d31–32 (p = 0.03; FDR non-significant) in comparison with the control diet. Additionally, on d31–32, CP2% increased the relative abundance of Megasphaera spp. compared to control values (p = 0.03; FDR non-significant). In conclusion, CP2% promoted the growth of beneficial bacterial communities in both post-weaning time points, modulating colonic fermentation patterns in the colon. The effects of CP supplementation were similar to those of IN and showed the potential as a beneficial feed supplement to alleviate weaning stress.

Coated Zinc Oxide Improves Growth Performance of Weaned Piglets via Gut Microbiota

“…What is more, the relieved diarrhea incidence resulting from ZnO and C_ZnO treatment was also in line with the notable effect of ZnO (19,20). Diarrhea was accompanied by ruined villi and a slow cell renewal rate, leading to disorders of nutrient absorption, eventually causing growth retardation in weaned piglets (21). In the present research, ZnO and C_ZnO both elevated the villus height in the foregut, which broadened the intestinal absorption surface area.…”

Prebiotics and β-Glucan as gut modifier feed additives in modulation of growth performance, protein utilization status and dry matter and lactose digestibility in weanling pigs

“…Each pen, housing 6 piglets of 3 barrows and 3 gilts, represented an experimental unit. The dietary inclusion at the level of 0.75% for the three prebiotics and the oat b-glucan in the experimental diets were to reflect the ranges of their dietary supplementation levels reported in the current literature (Mair et al, 2010;Park et al, 2018;Xing et al, 2018;Uerlings et al, 2021) in hopefully eliciting positive changes in growth performance, nutrition and and/or physiological endpoints while also being economically feasible for the industry should commercial applications of these potential gut modifiers as feed additives be attempted.…”

“…Furthermore, Mair et al (2010) added inulin to weaning pig diets at 0.40% and could not find any improvements in growth performances. Uerlings et al (2021) shown citric pulp supplemented at 0.20% was equivalent to 0.20% inulin in improving intestinal parameters in weanling pigs. Again, results of this study and the reviewed literature reports of different dietary supplementation levels of inulin as a potential gut modifier feed additive conducted under various experimental conditions do not support improvements in promoting growth performances in weanling pigs.…”

“…When included as a functional ingredient (at 5%) in diets, dietary supplementation of crude inulin extract reduced fecal excretion of a key odor compound of skatole and inconsistently modulated efficiency of nutrient utilization in grower pigs ). However, weaning pig studies with inulin as feed additives did not reveal significant improvements in growth performances (Pierce et al, 2005;Mair et al, 2010;Uerlings et al, 2021). Overall, there are limited studies regarding prebiotics as gut modifier feed additives to enhance growth and nutrient utilization in weanling pigs.…”

“…The results of no effects of dietary supplementation (at 0.75%) of Fibersol-2 on the total tract DM digestibility are consistent with the results in the study by Xing et al (2018) with dietary supplementation (up to 0.40%) of the gradient levels of Fibersol-2 in weanling pigs. Previous studies with inulin supplemented as a gut modifier feed additive primarily focused on gut mucosal morphology and microbiota responses without reporting nutrient digestibility in weanling pigs (Pierce et al, 2006;Mair et al, 2010;Uerlings et al, 2021). Thus, it is inconclusive about the effects of dietary supplementations of RS as a gut modifier feed additive on nutrient digestibility in weanling pigs.…”