Transversal gene expression panel to evaluate intestinal health in broiler chickens in different challenging conditions

Abstract

There is a high interest on gut health in poultry with special focus on consequences of the intestinal diseases, such as coccidiosis and C. perfringens-induced necrotic enteritis (NE). We developed a custom gene expression panel, which could provide a snapshot of gene expression variation under challenging conditions. Ileum gene expression studies were performed through high throughput reverse transcription quantitative real-time polymerase chain reaction. A deep review on the bibliography was done and genes related to intestinal health were selected for barrier function, immune response, oxidation, digestive hormones, nutrient transport, and metabolism. The panel was firstly tested by using a nutritional/Clostridium perfringens model of intestinal barrier failure (induced using commercial reused litter and wheat-based diets without exogenous supplementation of enzymes) and the consistency of results was evaluated by another experiment under a coccidiosis challenge (orally gavaged with a commercial coccidiosis vaccine, 90× vaccine dose). Growth traits and intestinal morphological analysis were performed to check the gut barrier failure occurrence. Results of ileum gene expression showed a higher expression in genes involved in barrier function and nutrient transport in chickens raised in healthy conditions, while genes involved in immune response presented higher expression in C.perfringens-challenged birds. On the other hand, the Eimeria challenge also altered the expression of genes related to barrier function and metabolism, and increased the expression of genes related to immune response and oxidative stress. The panel developed in the current study gives us an overview of genes and pathways involved in broiler response to pathogen challenge. It also allows us to deep into the study of differences in gene expression pattern and magnitude of responses under either a coccidial vaccine or a NE.

Influence of Brassica spp. rapeseed and canola meal, and supplementation of bioactive compound (AITC) on growth performance, intestinal-permeability, oocyst shedding, lesion score, histomorphology, and gene expression of broilers challenged with E. maxima

“…This is one of the pathways leading to decreased growth performance during challenge. Although coccidiosis may damage mucosa, triggering impaired absorption of nutrients ( Criado-Mesas et al, 2021 ), gene expression of MUC2 (component of mucus layer) was numerically reduced in the present study. As AITC are known candidates to reduce oxidative stress, the challenged birds should have coped up with the inflammation associated with oxidative stress which is responsible for changes in gene expression ( Criado-Mesas et al, 2021 ).…”

“…Although coccidiosis may damage mucosa, triggering impaired absorption of nutrients ( Criado-Mesas et al, 2021 ), gene expression of MUC2 (component of mucus layer) was numerically reduced in the present study. As AITC are known candidates to reduce oxidative stress, the challenged birds should have coped up with the inflammation associated with oxidative stress which is responsible for changes in gene expression ( Criado-Mesas et al, 2021 ). The gene expression in the intestine also depends on the severity as in case of necrotic enteritis genes are more profoundly expressed compared to mild-coccidiosis ( Criado-Mesas et al, 2021 ).…”

“…Because Eimeria spp. cause severe intestinal damage, the proper tools/ biomarkers that could identify intestinal entities related to infection would be great help to evaluate mitigation strategy and nutritional manipulation during infection by Eimeria or prophylaxis to control before exposure ( De Meyer et al, 2019 ; Criado-Mesas et al, 2021 ). Some of the most studied parameters are gut permeability, intestinal histomorphology, intestinal lesion score, gene expression related to intestinal barrier proteins, nutrient transporters, and immune genes ( Teng et al, 2020a ; Yadav et al, 2020 ).…”

“…The 1000AITC group had similar jejunum VH as NC group although the cell turnover rate was high in the ileum, causing significantly higher CD leading to decreased VH: CD ratio in the ileum for 1000AITC fed birds. According to Criado-Mesas et al (2021) , the higher cell turnover in Eimeria challenged birds is due to activation of mTOR complex 1 pathway to reduce the intestinal mucosal disturbance. Previous studies showed no difference in VH and VH: CD ratio when canola was included up to 40% ( Figueiredo et al, 2003 ; Chiang et al, 2009 ).…”

Impacts of increasing challenge with Eimeria maxima on the growth performance and gene expression of biomarkers associated with intestinal integrity and nutrient transporters

“…The “apoptosis-induced proliferation” is crucial for tissue regeneration and recovery [ 32 ]. It has been reported that coccidiosis could accelerate the renewal of intestinal epithelial cells [ 33 , 34 ]. Moreover, the increased epithelial cell turnover rate may expel parasites from the host’s intestine [ 35 ]; therefore, regulating gene expression in the enterocytes may lead to nutrient depletion and cell apoptosis which remove parasites from the host with the assistance of an increased proliferation of epithelial cells.…”