Digestibility and pricing of Chlorella sorokiniana meal for use in tilapia feeds

Daniel Yokoyama Sonoda,Evandro Kleber Lorenz,Rafael Simões Coelho Barone,José Eurico Possebon Cyrino

doi:10.1590/1678-992x-2016-0457

Abstract

Several microalgae contain in excess of 50 % crude protein with amino acid profile comparable to that of fish meal. In addition, high polyunsaturated fatty acid contents encourage their use in animal feeding and nutrition, particularly in the formulation and processing of aquafeeds. This study aims at estimating the feasibility of Chlorella meal as feed ingredient for the feeding and nutrition of farmed tilapia based upon digestibility data. Juvenile tilapia were stocked in conical-bottomed tanks (200 L) with superficial, continuous water flow, and fed to apparent satiation in three daily meals with a reference diet and a test diet containing 30 % lyophilized Chlorella sorokiniana added of an inert marker. Feces were collected overnight by sedimentation in refrigerated, plastic containers coupled to the tanks and analyzed for determination of chemical composition and inert marker contents to estimate apparent digestibility coefficients (ADCs) of protein and energy of Chlorella meal; registered ADCs of Chlorella meal were 90.5 and 84.22, respectively. A pricing model considering the quantity of digestible nutrient was proposed based on ADCs of Chlorella and compared with the price of fishmeal (FM) and soybean meal (SBM). The indicative prices to elicit the use of Chlorella as a protein source rather than FM or SBM for the feed and nutrition of tilapia were 2.65 USD kg−1 and 0.66 USD kg−1, respectively.

Highlights

While the production of oils by plants such as palm, coconut and physic nut (Jatropha curcass) average 5,960, 2,689 and 1,982 L ha–1 yr–1, respectively, productivity estimates from laboratory data for some species of microalgae range on 10,000 and 60,000 L ha–1 yr–1 (Chisti, 2007; Chisti, 2008; Ranjitha and Vijayalakshmi, 2015; Singh and Singh, 2014)
This study aims at estimating the feasibility of Chlorella meal as feed ingredient for the feeding and nutrition of farmed tilapia based upon digestibility data
Amino acid and macronutrients digestibility of Chlorella sorokiniana meal The composition and digestibility of protein, energy and amino acids found for CSM were similar to those of FM and soybean meal (SBM) (Table 2)

Summary

Introduction

While the production of oils by plants such as palm, coconut and physic nut (Jatropha curcass) average 5,960, 2,689 and 1,982 L ha–1 yr–1, respectively, productivity estimates from laboratory data for some species of microalgae range on 10,000 and 60,000 L ha–1 yr–1 (Chisti, 2007; Chisti, 2008; Ranjitha and Vijayalakshmi, 2015; Singh and Singh, 2014). Production of biodiesel from microalgae was never shown economically competitive because of high costs associated with agglutination, centrifugation, drying and lysis of cells for extraction of lipids (Demirbas and Demirbas, 2011; Nascimento et al, 2014). In this scenario, research on the use of microalgae by the pharmaceutical and cosmetics industries, human and animal nutrition has gained grounds in recent years. The use of microalgae in fish nutrition has been considered as a tool to enhance filet quality via deposition of n-3 PUFA, and replacement of fish meal and fish oil in aquafeeds (Christaki et al, 2011; Becker, 2007; Sarker et al, 2016a; Sarker et al, 2016b; Tulli et al, 2012; Tibaldi et al, 2015; Roy and Pal, 2015)

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