Effects of Dietary Indole-3-carboxaldehyde Supplementation on Growth Performance, Intestinal Epithelial Function, and Intestinal Microbial Composition in Weaned Piglets

Abstract

As a microbial tryptophan metabolite, indole-3-carboxaldehyde (ICA) has been suggested to confer benefits to host, such as regulation of intestinal barrier function. This study aimed to elucidate the role of ICA in modulating intestinal homeostasis via using a weaned pig model. Twenty-four weaned piglets were randomly allocated into three groups: the control group (a basal diet), ICA100 group (the basal diet supplemented with 100 mg/kg ICA), and ICA200 group (the basal diet supplemented with 200 mg/kg ICA). The experiment lasted 14 d, and pigs from the control and ICA100 groups were slaughtered. The results showed no significant differences in the average daily gain (ADG) and average daily feed intake (ADFI) among the three groups (P > 0.05). However, the ICA100 group had a lower feed to gain ratio (F:G) (P < 0.05). Dietary ICA supplementation did not alter the villus height, crypt depth, and villus height/crypt depth ratio in the small intestine, and did not change the intestinal permeability and antioxidant parameters (P > 0.05). Intriguingly, ICA treatment significantly increased the jejunal, ileal and colonic indexes in piglets (P < 0.05). Besides, the expression of proliferating cell nuclear antigen (PCNA) in the intestine was up-regulated by ICA treatment. Moreover, in vitro experiments demonstrated that 15 μM ICA significantly accelerated the proliferation activity of IPEC-J2 cells, and increased the expression of the ICA receptor aryl hydrocarbon receptor (AHR) and the proliferation markers PCNA and Cyclin D1 (P < 0.05). In addition, dietary ICA supplementation modulated the intestinal flora, increasing the richness estimators and diversity index, decreasing the abundances of phylum Fibrobacterota and genera Alloprevotella, Prevotella, and Parabacteroides, and enriching the abundance of genera Butyrivibrio. These data reveal a beneficial role for the microbial metabolite ICA on intestinal epithelial proliferation, rather than intestinal barrier function, in weaned piglets.

Intestinal melatonin levels and gut microbiota homeostasis are independent of the pineal gland in pigs

“…It is believed that cellulose hydrolysis, anerobic metabolism, and the absence of motility are the unified characteristics of Fibrobacterota (Abdul Rahman et al, 2015 ). A recent study suggests that indole-3-carboxaldehyde, a tryptophan metabolite produced by bacteria, decreased the abundance of phylum Fibrobacterota, which had a beneficial role in intestinal health in weaned piglets (Zhang et al, 2022 ). Thus, we speculated that MEL, which is also a tryptophan derivative and an indole-like neuroendocrine hormone, may have the same inhibitory mechanism on Fibrobacterota and improve intestinal health.…”

“…Four months after surgery, the animals were euthanized by the carotid artery bleeding under anesthesia with 2% pentobarbital sodium (0.5 mL/kg) at 20:00 p.m. After laparotomy, the brain, heart, liver, spleen, lung, kidney, and testis were excised and weighted. The middle part of the GIT from the stomach to the rectum and samples of the digesta from six intestinal segments were collected as previously described (Zhang et al, 2022 ). After washing with phosphate-buffered saline, one part of the GIT was fixed with 4% paraformaldehyde and the other was frozen in liquid nitrogen.…”

Early-life ruminal microbiome-derived indole-3-carboxaldehyde and prostaglandin D2 are effective promoters of rumen development

“…However, we did not compare the different effect between 3-IAld and butyrate, which is always considered to be the main ruminal microbial metabolite promoting rumen epithelial development [ 45 ]. Nevertheless, it seems that the effects of 3-IAld and PGD2 on gut epithelial and muscle tissues have been previously established [ 48 , 49 ], but the rumen stratified squamous epithelium structure differ from gut simple columnar epithelium and represent special microbial niche compartmentalization. Lastly, except for ruminal 3-IAld and PGD2, the contributions to rumen development of other characteristic ruminal metabolites related to corn-soybean starter or alfalfa hay introduction need to be further explored.…”

Turning Microbial AhR Agonists into Therapeutic Agents via Drug Delivery Systems

“…In murine models, endogenous or administered 3-IAld was associated with resistance to infections, ionizing radiation, inflammaging, and gut, cerebral, and liver inflammation via a plethora of mechanisms, including the production of IL-22 and type I interferons, the modulation of IL-10 and IL-10R expression, NF-kB and TLR7 activity, the promotion of epithelial barrier function, and cross-talk with enteric neurons and the microbiota [ 33 , 34 , 38 , 39 , 40 , 41 , 42 ]. In weaned piglets, dietary supplementation of 3-IAld significantly increased the jejunal, ileal, and colonic indexes and modulated the intestinal flora [ 43 ]. Of interest, an alteration in the microbial composition may change the levels of 3-IAld in human diseases.…”