Coloration enhancement in Procambarus clarkii crayfish through dietary supplementation of phycocyanin extracted from Arthrospira platensis BUUC1503.

Background and aim: The effects of phycocyanin (PC) on pigmentation have been extensively studied in fish; however, its specific impact on crustaceans, particularly Procambarus clarkii, remains underexplored. This study aimed to evaluate the impact of PCs extracted from Arthrospira platensis BUUC1503 on the color enhancement of P. clarkii crayfish when added to food pellets.

Materials and methods: The following five dietary treatments were prepared: a control (without PC) and four experimental diets with PC supplementation at concentrations of 10, 50, 100, and 500 mg/kg. The stability of the pellets in water was ensured for 180 min. P. clarkii crayfish were fed these diets at 5% of their body weight daily for 10 weeks. Body weight and total length were measured. Color changes in P. clarkii were also assessed. After the experiments, we treated the samples according to Animal Welfare Technical Information No.16.8 Correct euthanasia of decapods.

Results: Although PC supplementation did not significantly affect the yellowness (b* value) of P. clarkii, it significantly enhanced the redness (a* value) and lightness (L* value) pigmentation compared with the control. At week 10, crayfish fed a diet containing 100 mg/kg PC exhibited the highest L* value (36.51 ± 1.59) (p < 0.001). Diet with 500 mg/kg PCs had the highest a* value (26.96 ± 0.64) (p < 0.001). Crayfish fed 50, 100, or 500 mg/kg PC had the highest survival rate (100%). PCs appear to positively affect weight gain in P. clarkii crayfish during weeks 8, 9, and 10 (p = 0.013, 0.003, and 0.034, respectively). However, statistical analysis revealed no significant differences in length among the dietary treatments.

Conclusion: PCs effectively weight-gain and enhance red pigment deposition in the epidermal layer of P. clarkii. Further investigation is warranted to elucidate the underlying mechanisms.