Dietary Spirulina platensis phycocyanin enhances growth performance, antioxidant status, and immune-related gene expression in Japanese quails (Coturnix japonica)

Abstract

Abstract The study aimed to evaluate the effects of dietary phycocyanin extracted from Spirulina Platensis (PSP) supplementation on the expression of antioxidant and immune associated genes, growth performance related parameters, blood biochemical components, and hematological profiles in Japanese quails (Coturnix japonica). A total of 320 male Japanese quails, 7 days old, were randomly assigned to four experimental groups, each consisting of four replicates with 20 quails per replicate (80 quails per group). The quails were fed basal diets supplemented with PSP at concentrations of 0 (PSP0), 1 (PSP1), 2 (PSP2), and 3 (PSP3) g/kg of diet. The results showed that quails fed diets supplemented with 3 g of PSP /kg diet had significantly better growth performance and feed efficiency compared to the other groups (P < 0.001). Increasing dietary PSP levels resulted in a significant, dose-dependent improvement in hematological parameters (P < 0.001). Dietary supplementation with PSP (1, 2–3 g/kg diet) resulted in a significant dose-dependent increase in total protein (TP), triglycerides (TG), globulins, and lysosomal activity (P < 0.001). Conversely, serum levels of alanine aminotransferase (ALT), creatinine, total cholesterol (TC), and urea exhibited a significant, dose-dependent decrease with increasing PSP supplementation (P < 0.001). Additionally, including PSP in the diets of Japanese quails led to significant improvements in small intestinal and liver morphology. Dietary supplementation with PSP significantly upregulated the mRNA expression of antioxidant defense genes (Catalase (CAT) and glutathione peroxidase (GPX)). However, the mRNA expression of pro-inflammatory cytokine genes, specifically interleukin 8 (IL-8) and interleukin 1 beta (IL-1β), exhibited a dose-dependent decrease with elevated dietary phycocyanin extracted from PSP concentrations. In conclusion, dietary supplementation with PSP promotes growth performance and feed efficiency, enhances antioxidant defense, upregulates growth-related gene expression, and improves organ histomorphology.