The effect of different carbon sources on the nutritional value of bioflocs, a feed forMacrobrachium rosenbergiipostlarvae

Abstract

A 15-day lab-scale experiment was performed to determine the possible use of bio£ocs as a feed for Macrobrachium rosenbergii postlarvae. The bio£ocs were grown on acetate, glycerol and glucose. A glycerol-fed reactor was initially inoculated with a Bacillus spores mixture. The highest protein content was obtained in the (gly-cerol1Bacillus) bio£ocs, i.e.58 AE 9% dry weight (DW). The glycerol and acetate bio£ocs showed a lower, but similar content (42^43% DW) and glucose bio£ocs contained 28 AE 3% DW. Higher total n-6 fatty acid contents were observed in the glycerol and (glycerol1 Bacillus) bio£ocs. The vitamin C content was variable, up to 54 mg ascorbic acid g À 1 DW in the glycerol bio-£ocs. Bio£ocs were fed to M. rosenbergii postlarvae as the sole feed. High survival levels were obtained in the (glycerol1Bacillus) and glucose groups, i.e. 75 AE 7% and 70 AE 0% respectively. This was signi¢cantly higher than the starvation control (0% survival after 15 days). This indicated that the prawns were able to feed on the bio£ocs. These results are in accordance with the bio£oc's nutritional parameters and suggest that the choice of the carbon source used for growing bio£ocs is of prime importance.

Evaluation of dietary soybean meal as fish meal replacer for juvenile whiteleg shrimp, Litopenaeus vannamei reared in biofloc system

“…Biofloc biomass in the culture system that is consumed by cultured shrimp and digested, may compensate a significant amount of protein demand, and consequently reduce the quantity of fish meal (FM) required (Burford et al 2004;Crab et al 2010;Hari et al 2004;Wasielesky et al 2006;.…”

Biofloc technology: an emerging avenue in aquatic animal healthcare and nutrition

“…This increase was based on the internal recirculation of nutrients through the formation of new microbial biomass, which was subsequently grazed by the fish (Avnimelech 2006). The advantages of the technology in aquaculture has been well documented which includes low feed and water input (economical), less risk of pathogen introduction and diseases, more biosecurity, increased growth and survival, and hence increased crop yield (Otoshi et al 2009;Crab et al 2009;Samocha et al 1998Samocha et al , 2007Krummenauer et al 2011;Perez-Fuentes et al 2013). It also lowered the feed conversion rate by utilizing the in situ natural feed and has small footprints, hence reducing environmental impacts (Krummenauer et al 2014).…”

“…It is also robust, easy to operate, and economically feasible (Crab et al 2012). The zero water exchange system has advantages of maintaining temperature and heat fluctuations (Crab et al 2009). It supports nitrogen removal even when organic matter and biochemical oxygen demand of the system is high (Avnimelech 2015).…”

“…Thus the change in the carbon source changes the nutritional composition and quality index of the flocs. Besides these characteristics, the type of carbon source also influences the palatability and digestibility of the cultured organisms (Crab 2010a;Crab et al 2009). Overall, bioflocs produced on glycerol gave the best results (Crab 2010a).…”

“…Although bioflocs meet nutritional standards, nutritional properties and the ability to maintain water quality in the BFT system depend on the carbon source used to produce the flocs. Different carbon sources are not only used to manipulate the C/N ratio and stimulate the specific bacteria, protozoa, and algae but also to influence the microbial composition and community organization of the bioflocs (Crab et al 2009;Crab 2010a). L. vannamei production rates and water quality were maintained without water exchange using a biofloc system supplemented with dextrose or molasses (Antonio et al 2015).…”