The impact of Spirulina platensis supplementation on performance and immune response in laying hens.

This study evaluated the effects of dietary supplementation with different levels of Spirulina platensis (SP) on laying performance, immune response, serum fatty acid profile of laying hens and SP's in vitro antioxidant capacity. About 160 hens were assigned to four dietary treatments: control (0) and SP-supplemented diets (1.5, 3, and 4.5 g/kg diet). Supplementation with SP showed notable, significant positive effects on laying rate (92.9-94.5%), egg weight (62.2-67.1 g), egg mass, yolk color, shell quality traits, and feed conversion ratio compared to the control group (P < 0.05). SP supplementation also enhanced the humoral immune response, as shown by increased Newcastle disease antibody titers, particularly at 1.5 and 3 g/kg during the first 60 days. Gas Chromatography-Mass Spectrometry (GC-MS) analysis of serum fatty acid profile revealed a dose- and time-dependent increase in beneficial unsaturated fatty acids and a marked reduction in cholesterol levels in SP-fed hens. In vitro evaluations showed that SP extract had potent antioxidant activity with 2, 2-azino-bis-3 ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity comparable to vitamins C and E, particularly at high concentrations (3 and 4.5 g/kg). These results highlight the promising potential of Spirulina platensis as a functional, natural feed additive to improve the laying performance, egg quality, immune response, yolk fat and provide potent antioxidant protection in poultry production systems.