The gut–liver axis represents a bidirectional communication network for maintaining metabolic and immunological homoeostasis. Alterations in this axis allow bacterial products to reach the liver via the portal vein, promoting inflammation, oxidative stress and lipid accumulation. In this scenario, the consumption of bioactive compounds has become prominent due to its antioxidant and anti-inflammatory effects. This study aimed to investigate the effects of camu-camu (Myrciaria dubia) extract, an Amazonian fruit rich in phenolic compounds, on intestinal morphology, barrier-related gene expression and hepatic outcomes of chicken (Gallus gallus) embryos exposed to dextran sulfate sodium (DSS). Fertile eggs were divided into three groups (n 20/group): water (control), DSS (1·5 %), and camu-camu (10 %) + DSS (1·5 %). On the seventeenth day of embryonic development, treatments were injected into the amniotic fluid, and samples were collected at hatching (twenty-first day). Results showed that camu-camu was associated with changes in intestinal histomorphology, increasing villus height, surface area and the number of goblet cells, along with increased expression of selected barrier-related genes (MUC2, CLDN-1 and ZO-2). In the liver, camu-camu significantly reduced NF-κB expression compared with the DSS and water-treated groups, consistent with modulation of inflammatory-related gene expression. Furthermore, the decreased expression of iNOS, CAT and SOD-1 indicates modulation of oxidative stress-related gene expression markers. Histological analysis indicated alterations in hepatic morphology, including reduced lipid droplets and inflammatory infiltrates. These findings indicate that camu-camu is associated with changes in intestinal histomorphology, selected barrier-related gene expressions, hepatic histology and inflammatory- and oxidative stress-related gene expression markers.

In the post-antibiotics era, prebiotics are proposed as alternatives to antibiotic growth promoters in poultry production. The goal of this study was to compare in ovo method of prebiotic delivery with in-water supplementation and with both methods combined (in ovo+in-water) in broiler chickens. Two trials were conducted. Trial 1 was carried out to optimize the doses of two prebiotics, DN (DiNovo®, extract of beta-glucans) and BI (Bi2tos, trans-galactooligosaccharides), for in ovo delivery. The estimated parameters were hatchability and bacteriological status of the newly hatched chicks. Prebiotics were dissolved in 0.2 ml of physiological saline, at the doses: 0.18, 0.88, 3.5 and 7.0 mg/embryo; control group (C) was injected in ovo with 0.2 ml of physiological saline. Trial 2 was conducted to evaluate effects of different prebiotics (DN, BI and raffinose family oligosaccharides (RFO)) delivered in ovo, in-water and in a combined way (in ovo+in-water) on broiler chickens performance. The results of the Trial 1 indicated that the optimal dose of DN and BI prebiotics delivered in ovo, that did not reduce chicks’ hatchability, was 0.88 mg/embryo (DN) and 3.5 mg/embryo (BI). Both prebiotics numerically increased number of lactobacilli and bifidobacteria in chicken feces (P>0.05). In Trial 2, all prebiotics (DN, BI and RFO) significantly increased BW gain compared with the C group (P<0.05), especially during the first 21 days of life. However, feed intake and feed conversion ratio were increased upon prebiotics delivery irrespective of method used. Injection of prebiotics in ovo combined with in-water supplementation did not express synergistic effects on broilers performance compared with in ovo injection only. Taken together, those results confirm that single in ovo prebiotics injection into the chicken embryo can successfully replace prolonged in-water supplementation post hatching.