Email this article (Login required)
Email the author (Login required) Application of agricultural phytohormones in carotenoid biosynthesis in Arthrospira platensis: effects on productivity and hematological health of Oncorhynchus mykiss
Submited: 2025-09-01 10:22:39 | Published: 2026-01-07 14:47:41
DOI: https://doi.org/10.3856/vol54-issue1-fulltext-3525
Abstract
Arthrospira platensis is a cyanobacterium of high nutraceutical value, notable for its rich protein, polyunsaturated fatty acids, essential minerals, vitamins, and bioactive pigments, including β-carotene, phycocyanin, and chlorophylls. This study evaluated the effect of agricultural hormones (AH)-indole-3-acetic acid (IAA), gibberellins (GA), and abscisic acid (ABA)-on β-carotenoid production. IAA was tested at 5 and 10 ppm. Under stable conditions, AH treatments enhanced growth, with IAA at 5 ppm achieving the highest density (1.2×106 filaments mL-1), significantly outperforming ABA and the controls (P < 0.05). Pigment responses varied: chlorophyll-a and b peaked at 10 ppm, while β-carotenoids were maximized at 5 ppm. Higher concentrations (>10 ppm) inhibited growth. Biomass from AH-treated cultures was incorporated into trout fry diets and tested over 50 days. Fish fed treated Arthrospira showed marked improvements, with body weight increasing from 2.70 ± 0.13 to 32.70 ± 4.11 g and length from 6.23 ± 0.09 to 13.84 ± 0.575 cm (P < 0.05). Diets containing IAA and ABA yielded the highest daily growth rates (463.4 and 406.39 mg d-1, respectively) compared to controls (323-334 mg d-1). Feed efficiency, food conversion rate, and condition factor were enhanced, with survival highest in the ABA group (98.3 vs. 85%). Under stress conditions, treated fish exhibited enhanced hematological and biochemical responses, including elevated white blood cell counts, glucose levels, and globulin levels. Superoxide dismutase activity in blood plasma was significantly higher (P < 0.05), ranging from 4.76 to 6.32 U mL-1. Overall, AH supplementation increased pigment yield in A. platensis and significantly enhanced growth, metabolism, antioxidant defense, and stress resilience in rainbow trout (Oncorhynchus mykiss) during early culture stages.
