Phytogenic feed additives alleviate pathogenic Escherichia coli-induced intestinal damage through improving barrier integrity and inhibiting inflammation in weaned pigs

Abstract

Background This study was conducted to investigate the effects of each phytogenic feed additive (PFA; PFA1, bitter citrus extract; PFA2, a microencapsulated blend of thymol and carvacrol; PFA3, a mixture of bitter citrus extract, thymol, and carvacrol; PFA4, a premixture of grape seed, grape marc extract, green tea, and hops; PFA5, fenugreek seed powder) on the growth performance, nutrient digestibility, intestinal morphology, and immune response in weaned pigs infected with Escherichia coli (E. coli). Results A total of 63 4-week-old weaned pigs were placed in individual metabolic cages and assigned to seven treatment groups. The seven treatments were as follows: 1) NC; basal diet without E. coli challenge, 2) PC; basal diet with E. coli challenge, 3) T1; PC + 0.04% PFA1, 4) T2; PC + 0.01% PFA2, 5) T3; PC + 0.10% PFA3, 6) T4; PC + 0.04% PFA4, 7) T5; PC + 0.10% PFA5. The experiments lasted in 21 d, including 7 d before and 14 d after the first E. coli challenge. In the E. coli challenge treatments, all pigs were orally inoculated by dividing a total of 10 mL of E. coli F18 for 3 consecutive days. The PFA-added groups significantly increased (P < 0.05) average daily gain and feed efficiency and decreased (P < 0.05) the fecal score at d 0 to 14 post-inoculation (PI). Tumor necrosis factor α was significantly lower (P < 0.05) in the PFA-added groups except for T1 in d 14 PI compared to the PC treatment. The T3 had a higher (P < 0.05) immunoglobulin G and immunoglobulin A concentration compared to the PC treatment at d 7 PI. Also, T3 showed significantly higher (P < 0.05) villus height:crypt depth and claudin 1 expression in ileal mucosa, and significantly down-regulated (P < 0.05) the expression of calprotectin compared to the PC treatment. Conclusions Supplementation of PFA in weaned pigs challenged with E. coli alleviated the negative effects of E. coli and improved growth performance. Among them, the mixed additive of bitter citrus extract, thymol, and carvacrol showed the most effective results, improving immune response, intestinal morphology, and expression of tight junctions.

Beneficial Effects of Phytogenic Feed Additives on Epithelial Barrier Integrity in an In Vitro Co-Culture Model of the Piglet Gut

“…Direct exposure of PBMC to both PFAs had a larger effect on the test system than direct exposure of IPEC-J2 in the apical compartment, as only trends for barrier protection could be observed for apical extract application. This may be explained by the anti-inflammatory effects of active compounds [ 20 , 25 , 40 , 44 , 45 , 46 ] directly on site, counteracting the inflammation reaction and barrier integrity challenge simulated by activation of basolateral PBMC by ConA. After 72 h of incubation, no significant effects or trends compared with the ConA control could be observed in all treatment groups, indicating reduced efficacy of treatments over time.…”

“…In vivo , blends of carvacrol and thymol have also been reported to support intestinal barrier integrity, e.g., by reducing oxidative stress and modulating the jejunal microbiome of piglets after weaning [ 9 ]. PFA mixtures containing carvacrol and thymol have been reported to improve intestinal morphology, immune response, and the expression of tight junction proteins important to intestinal barrier integrity in E.coli -challenged weaned piglets [ 20 ]. Oregano essential oil, containing both carvacrol and thymol, has been linked to improved intestinal barrier integrity and beneficial effects on growth performance [ 10 , 55 ].…”

“…Hence, it must be of utmost interest for individual small-scale farmers, as well as bigger farming conglomerates, and any dependent connected business and industry, to improve animal welfare and health at the farm level and continuously improve feed and feed additives. Phytochemicals and plant-derived feed additives (PFA or so-called phytogenics) [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ], probiotics [ 4 , 13 , 14 ], as well as other substances of natural or synthetic origin, and optimized feeding strategies [ 3 ] can be used to improve piglet GI health and growth performance during all rearing stages, e.g., during [ 15 , 16 ] and after weaning [ 17 , 18 , 19 , 20 ]. Livestock should be enabled to better deal with the numerous challenges of industrial farming, rather than solely rely on reactive treatment of illnesses, underperformance, and poor animal welfare.…”

Effects of dietary supplementation with a carvacrol–cinnamaldehyde–thymol blend on growth performance and intestinal health of nursery pigs

“…The following two experimental diets were given to the piglets: a control diet (Con) fed with basal ration only; a diet with a 0.1% replacement additive consisting of CEO. The CEO dose was selected based on previous studies [ 13 , 45 ]. In the 42d trial, 100 piglets were randomly allotted to the 2 previously described dietary treatments according to body weight and gender, each consisting of 50 piglets in 5 replicate pens per group and 10 piglets per pen.…”

Effects of different stocking density and various phytogenic feed additives dosage levels on growing-finishing pigs

“…They are often supplemented into animal diets [6]. Many studies have reported positive effects of PFA on animal health and growth performance under various stress environments [7,8]. However, their function and impact can vary depending on plant origin, extraction method, formulation.…”