Utilizing Alternative Carbon Sources for Biofloc System for Growth and Survival of Pacific Whiteleg Shrimp (Litopenaeus vannamei)

Abstract

Selection of a suitable carbon source is crucial in the advancement of biofloc technology. This study aims to evaluate the usability and effect of leftover bread and surplus rice as carbon source for the biofloc system for growth and survival of Pacific whiteleg shrimp (Litopenaeus vannamei). Biofloc was developed 2 weeks before stocking using probiotics (0.03 g/L) with carbohydrate (0.1 g/L) source. The experimental treatments: T0 (clear water), T1 (leftover bread), T2 (surplus rice), and T3 (50% surplus rice+50% leftover bread) replicated three times. Stocked with 12 postlarvae (PL10) weighing 0.028–0.052 g each (6PL/L), parameters were regularly monitored. During a 30-day culture period, shrimp were fed twice daily with a diet containing 55% protein, and the carbon source was maintained at a C:N ratio of 15:1. One-way ANOVA of sampling data (collected every 15 days) indicated no significant differences (p > 0.05) in growth performance, survival rate, and feed conversion ratio (FCR) across treatments. Physicochemical parameters of the water are at the optimum; the leftover bread biofloc attained more ideal parameters (dissolved oxygen: 7.54, temperature: 27.30, salinity: 29.10, and pH: 7.6) due to simpler starch structure. Poor fermentation and slow degradation properties of leftover bread and surplus rice on biofloc formation were the reason why biofloc has no effect on shrimp growth and survival. Leftover bread shows promising results among the BFT treatments; for further study with greater area and period, additional parameters are encouraged.