New Insights into the Mucus-Secreting Cells in the Proventriculus of 10 Day Old Ross 308 Broiler Chickens—A Qualitative RGB Color Study by Histochemical Assessment

The proventriculus has an important adjustment function in broiler chickens, potentially impacting nutrient availability and performance. Given their contribution to protecting the gastric lining and facilitating digestion, the understanding of the mucus secretion cells within this organ is essential. Therefore, this study aims to investigate, through histochemical methods, the types of mucins secreted at the proventriculus level in 10 day old Ross 308 broiler chickens. Fragments of the proventriculus (five chickens) were histologically processed by paraffin embedding and the slides were stained using three techniques: periodic acid-Schiff (PAS) reaction, alcian blue (AB) staining pH 2.5, and combined PAS-AB staining. The color of the mucus present in the cells of the gastric mucosa was qualitatively assessed using the Photoshop Color Picker using the red, green, blue (RGB) color model and the numerical values for the RGB spectrum were analyzed from a statistical point of view. The synthesized mucus in the proventricular mucosa is predominantly PAS-positive in the superficial half of the mucosa and in the deep half, the synthesized mucins are both neutral and acidic with a predominance of acidic mucins. In the submucosa, only a few cells lining the central lumen of the glandular lobules are moderately PAS- and AB-positive.