Sustainable aquafeed development: Incorporating select fruit wastes into Zebrafish diets using mathematical model-based approach

Abstract

Expensive aquafeed is a major problem in aquaculture, creating the need for a low-cost feed that provides ideal nutritional requirement to maximize growth performances. This study aims to formulate and evaluate two new optimized Zebrafish feeds (F1 and F2) using linear programming mathematical model, one of which incorporates two pigment rich fruit wastes (Pitaya peel and Roselle calyx) in the formulation. The model represents nutritional content and cost of each ingredient into linear equations, with the goal of finding ideal combination that satisfies the specific nutrient requirements. By systematically evaluating ingredient proportions, linear programming ensures that Zebrafish receives adequate nutrients at the lowest possible cost, making the feed development process more efficient and cost-effective. The novel feed formulations derived from the mathematical model were tested on the growth and pigmentation of Zebrafish in comparison to a commercial feed (control). Feed intake of F1 and F2 were generally found to be similar to the control feed, indicating the acceptability of the formulated feeds by the Zebrafish. Body weight and length of Zebrafish fed with F1 and F2 were comparable to Zebrafish fed with control feed (p > 0.05). Similarly, Zebrafish fed with F1 and F2 showed no significant differences in pigment intensity compared to Zebrafish fed with control feed (p > 0.05). The survival rate of fishes in all feeding groups were greater than 70 % with no significant differences (p > 0.05). Results obtained in this study illustrated the potential of mathematic linear programming and effectiveness of utilising pigment-rich fruit wastes in formulating an optimized economic aquafeed.

Keywords: Antioxidant; Danio rerio; Low-cost feed; Optimization; Pitaya peel; Roselle calyx.

Fig. 1

Feed intake of zebrafish from different feeding groups at day-30 (A) and day-60 (B) of feeding trial. Formulation without inclusion of pitaya peel and roselle calyx decoction residue (F1), formulation with inclusion of pitaya peel and roselle calyx decoction residue (F2). Data is represented as mean ± standard error. Columns with different letter indicates significant difference (p < 0.05).

Fig. 2

Body weight of zebrafish from different feeding groups at day-30 (A) and day-60 (B) of feeding trial. Formulation without inclusion of pitaya peel and roselle calyx decoction residue (F1), formulation with inclusion of pitaya peel and roselle calyx decoction residue (F2). Data is represented as mean ± standard error.

Fig. 3

Body length of zebrafish from different feeding groups at day-30 (A) and day-60 (B) of feeding trial. Formulation without inclusion of pitaya peel and roselle calyx decoction residue (F1), formulation with inclusion of pitaya peel and roselle calyx decoction residue (F2). Data is represented as mean ± standard error.

Fig. 4

Percentage of zebrafish survival rate at day 30 (A) and day 60 (B) of feeding trial. Formulation without inclusion of pitaya peel and roselle calyx decoction residue (F1), formulation with inclusion of pitaya peel and roselle calyx decoction residue (F2).

Fig. 5

Skin colour of zebrafish from different feeding groups at day-30 of feeding trial measured using Adobe® Photoshop CS6 (A) and day-60 of feeding trial measured using Chroma meter CR-400 (B). Formulation without inclusion of pitaya peel and roselle calyx decoction residue (F1), formulation with inclusion of pitaya peel and roselle calyx decoction residue (F2). Data is represented as mean ± standard error.