Various types of dietary fats undergo distinct fermentation processes by gut microbes, potentially leading to the production of neurotransmitters that can influence the gut. Serotonin and dopamine are recognized neurotransmitters with positive effects on gut function. A broiler chicken trial was conducted to evaluate the influence of dietary fat types on protein expression of 2 neurotransmitter transporters, dopamine (DAT) and serotonin (5-HTT). A total of 560 day-old (Ross 708) male broiler chicks were randomly assigned to 7 dietary treatments. The experimental treatments included a basal diet of corn-soybean meal (SBM), supplemented with 3% of various fats: poultry fat (CON), olive oil (OLIV), fish oil (FISH), canola oil (CANO), lard (LARD), coconut oil (COCO), or flaxseed oil (FLAX). Bodyweight (BW) and feed conversion ratio (FCR) were recorded. Ileal tissues were aseptically collected to determine the expression levels of DAT and 5-HTT through western blot analysis. In addition, plasma samples were analyzed for reactive oxygen metabolites (d-ROM) tests on d 55. Results showed that dietary fat type inclusion did not have any detrimental effect on growth performance parameters. The expression levels of DAT were higher (P < 0.05) in FLAX treatments compared to CON treatments on d 20 and d 55, respectively. Similarly, with 5-HTT levels, FLAX, CANO, and LARD treatments were higher (P < 0.05) than CON treatments on d 20 and d 55. However, higher levels of oxidative stress (d-ROM values) were recorded in COCO (32.75 Carr U), CANO (29 Carr U), and CON treatments (25.5 Carr U) compared to FLAX (18.5 Carr U; P < 0.05) treatment. These findings suggest that incorporating dietary flaxseed oil at a 3% level in the diet has significant potential to elevate the expression levels of intestinal DAT and 5-HTT without inducing oxidative stress.

This study evaluated the effects of varying levels of dietary green tea extract (GTE) on growth performance, Clostridium perfringens (CP) colonization, and inflammatory responses in broiler chickens during experimental subclinical necrotic enteritis (SNE). In a 21-day experiment, 480 one-day-old male broiler (Ross 708) chicks were equally allotted into four dietary treatment groups. From days 1 to 10, all groups received a corn–soy basal diet, switching to a wheat-fish diet on day 11. Treatments included CON (no GTE), GTX, GTY, and GTZ (250, 500, and 1000 mg/kg GTE, respectively). On day 11, each group split into ACON, AGTX, AGTY, and AGTZ, totaling eight treatments. From days 17 to 20, ACON, AGTX, AGTY, and AGTZ chicks were orally challenged twice daily with 3 mL CP26 (2.5 × 10⁸ CFU/mL). On d 16 (pre-challenge) and d 1 post-challenge, ileo-jejunal contents were collected for CP enumeration, and jejunum tissue was analyzed via qRT-PCR to determine the expression levels of IL-1β, IFNγ, TNF-α, TGFβ, IL-10, and MUC2 genes. Challenged chicks showed poorer (p ≤ 0.05) growth and higher intestinal CP, with a potential improvement in GTE-supplemented diets. Findings suggests that dietary GTE supplementation mitigated the characteristic growth depression during SNE, reduced intestinal CP infection, and modulated inflammatory response in broiler chicks.

Spray-dried plasma (SDP) is a functional feed additive that has been established to improve performance and health of livestock. Understanding the effect of SDP in immune response modulation is essential to optimize its use for controlling Salmonella Enteritidis (SE) infection in chickens. This study was conducted to determine the levels of expression of selected cytokine genes in the ileum and cecal tonsil of SE-challenged broiler chicks. In a floor-pen housing, 320 broilers chicks were randomly assigned to 6 treatment groups: CX (unmedicated corn-soybean meal (SBM) basal without SDP), MX (unmedicated corn-SBM basal with antibiotic bacitracin methylene disalicylate (BMD) added at 0.055g/kg diet), PCX (unmedicated corn-SBM basal with SDP added at 30g/kg diet). Treatments SE, MSE, and PSE consisted of chicks inoculated with 7.46 x 10(8) CFU SE /mL at 1 d of age and given diets similar to CX, MX, and PCX, respectively. Samples of cecal tonsils and ileum were collected on d 3, 7 and 14 post infection for qRT-PCR analysis to determine the expression levels of interleukin (IL)-1 beta, interferon-gamma (IFN-gamma), IL-13, IL-17, IL-6, and transforming growth factor (TGF)-beta genes. In the ceca tonsils, expression of IFN-gamma was not affected by the interaction of Day and Treatment (P > 0.05). The level of the anti-inflammatory cytokine IL-13 was lower in MX and PCX on d 7 whereas high levels were expressed (P < 0.05) in MSE and PSE. In the ileum, expression of IL-17 and IFN-gamma was significantly lower (P < 0.05) in PSE and MSE, but only PSE expressed lower IL-6 comparable to unchallenged treatments. On d 28 postchallenge, concentrations of anti-SE IgY and IL-6 protein were higher (P < 0.05) in the SE-challenged treatments compared to the unchallenged treatments. Overall, these results suggest that dietary SDP showed similar potency to BMD in modulating intestinal cytokine response against intestinal SE colonization in broiler chicks and therefore can be considered suitable alternative replacement for antibiotics in broiler production.

Onion peel extract (OPE) is rich in polyphenolic compounds with antimicrobial potential. Salmonella Enteritidis (SE) infection in young broiler chicks causes morbidity, reduced growth, and contributes to human gastroenteritis through contaminated poultry products. The spleen is a key secondary lymphoid organ coordinating systemic responses to pathogens in chicken. This study evaluated how dietary OPE influences spleen metabolic profiles during SE infection. Day-old Ross 708 male chicks (n = 128) were assigned to four treatments: CON, CON-SE, OPE (6 g/kg), and OPE-SE. Chicks in CON and OPE received sterile broth, whereas CON-SE and OPE-SE received 2.25 × 10⁸ CFU/mL SE at 2 d of age. At 5 and 12 dpi, spleens from six chicks per treatment were collected for untargeted HPLC-MS metabolomics. A total of 857 metabolites were identified and analyzed using MetaboAnalyst 6.0 (p < 0.05; fold change ≥ 2.0; VIP score > 1.0). In CON-SE chicks, energy generating metabolites (6-phosphogluconic acid, methylmalonic acid, propionic acid) increased, while 13,14-dihydro-15-keto-prostaglandin D2 and kynurenic acid decreased. Dietary OPE elevated several dipeptides (L-Val-Gly, L-Leu-Gly, Gly-Gly-Leu, L-Val-L-Met) and reduced ATP linked metabolites (3,6-di-O-methyl-beta-D-glucose and 3-O-beta-D-galactosyl-sn-glycerol). Enrichment analysis showed that SE infection altered valine, leucine, and isoleucine degradation and aromatic amino acid biosynthesis, whereas OPE enriched galactose and biotin metabolism in uninfected chicks, but enriched tryptophan, taurine and hypotaurine metabolism in SE-infected chicks. Overall, dietary OPE optimized response of metabolic pathways associated with immune activation, unlike corresponding pathways in CON-SE birds.