Effect of dietary pumpkin flower on coloration and growth performance of swordtail fish (Xiphophorus helleri) in aquarium conditions

Abstract

The skin and fin color of ornamental swordtail fish (Xiphophorus helleri) is an important factor affecting their market value. This 84-day feeding trial aimed to evaluate the effects of dietary supplementation with pumpkin (Cucurbita maxima) flower powder on the coloration and growth performance of juvenile swordtails. The fish (Number of fish 90) with an initial average length of 2.020 ± 0.04a cm and weight of 0.097 ± 0.01a g were stocked into nine glass tanks (1.5 ft x 1.5 ft x 1 ft) at a density of 10 fish per tank. Three diets were formulated with equal amounts of proximate composition: a control diet without pumpkin flower powder (Diet CT), and diets containing either 2.5% (Diet PF2.5) or 5% (Diet PF5) pumpkin flower powder. Each diet was fed to fish in triplicate tanks. At the end of the trial, fish fed Diet PF5 had significantly (P<0.05) greater final length (6.678 ± 0.41a cm) and weight (5.193 ± 0.31a g), specific growth rate (5.936 ± 0.23a %/day), average daily gain (76.4 ± 13.7a %), and better feed conversion ratio (3.407 ± 0.01a) compared to the other diets. The final carotenoid content varied significantly among the three treatments: Diet CT (14.881 ± 0.29c), Diet PF2.5 (70.141 ± 0.85b),and Diet PF5 (85.47 ± 0.44a), indicating notable differences in carotenoid levels obtained. Skin and fin coloration demonstrated a positive correlation with the increment in dietary pumpkin flower powder. Higher muscular carotenoid content in fish-fed pumpkin diets indicated absorption and utilization of carotenoids supplied through the diets. The significant improvement in growth performance and color with Diet PF5 makes it a good solution for enhancing the commercial value of ornamental swordtails.