Effect of dietary natural carotenoid sources on colour enhancement of guppy, Poecilia reticulata (Wilhelm Peters, 1859)

Abstract

A 55-day feeding trial was carried out to investigate the effects of natural dietary carotenoids on the survival and colour enhancement of guppy fish (Poecilia reticulata). Four aquaria, each measuring 40 cm x 30 cm x 30 cm and stocked with 15 guppy fish, were used in the study. Four isonitrogenous @50%, (Ingredients: Fishmeal, wheat flour, mustard oil cake), were formulated with various natural carotenoid supplements: carrot powder, beetroot powder, turmeric powder and control (Devoid of carotenoid supplement). Additionally, 1% vitamin (Agrimin) was added to each diet. The study found that the highest survival rates were observed in T2 and T3 groups, where fish were fed with diets supplemented with beetroot and turmeric, respectively. The T1 group, which received the carrot diet, had a slightly lower survival rate, while the control group (T0) had the lowest survival rate. Colour analysis, performed using spectrophotometry to measure carotenoid content, revealed that the highest carotenoid content (1296±131.45 μg.g-1) was in T3 (Turmeric diet), followed by T2 (beetroot diet) with 1056±118.65 μg.g-1, and T1 (Carrot diet) with 976±381.15 μg.g-1. The control group had the lowest carotenoid content (57.6±19.91 μg.g-1). The t-test for two samples assuming equal variance indicated that adding dietary carotenoid sources such as carrot, beetroot, and turmeric significantly increased the total carotenoid content in Poecilia reticulata, thereby enhancing their coloration.