Presentation on theme: "TILAPIA PRODUCTION IN BIOFLOC SYSTEMS YORAM AVNIMELECH TECNION, ISRAEL INST. Of TECHNOLOGY"— Presentation transcript:
TILAPIA PRODUCTION IN BIOFLOC SYSTEMS YORAM AVNIMELECH TECNION, ISRAEL INST. Of TECHNOLOGY
» » Biofloc technology is based upon a few principles: » (a) Zero or minimal water exchange, » (b) subsequent development of dense microbial population » (c) managing the microbial population as a part of the pond eco-system » (d) adjustment of the C/N ratio to 15 in order to control inorganic nitrogen concentration in the water. » The bacteria, forming bioflocs, assimilate TAN, produce microbial proteins that is consumed by the fish, thus recycle the unused feed protein. (For more details: Yoram Avnimelech, Biofloc Technology, A Practical Handbook, World Aquaculture Soc. 2012).
Grow well in dense cultures Resistant FILTER FEEDER Very few studies as compared with shrimp
Normally, kg/m2 10 times higher than shrimp BFT ponds!
» High Biomass kg/m3 (Up to more than 40kg/m 3 » (w/o O 2 ) » High feeding (ca 500 g feed/m3 per day) » Very high microbial activity » High floc volume (20-50 ml/l). » Very high natural feed storage. » High levels of feed residues » Need to drain out daily (or twice daily) excessive sludge. » Pond constructed to facilitate sludge draining and perfect mixing. » High and effective aeration: hp/1000 m2 pond
» Bio flocs are made of bacteria, protozoa, feed residues etc. » Bioflocs size may reach A few mm diameter » Effectively harvested by tilapia
x20x µm Bio flocs are made of bacteria, protozoa, etc. Typicaly their diameter is mm.
» Normally, fish or shrimp recover just ~25% of feed protein. » In bacterial controlled ponds, they eat the protein twice; Once in the feed and then they consume microbial protein. The protein recovery reaches almost 50%. » Protein is the most expensive part of the feed.
BFT control Expt. # 1 51 days FEED C/N 2.0 b 1.59 a Daily Gain (%) FCR PCR FEED COST (US$/Kg fish) Exp. # 2 (30 days) C/N 2.22 b 1.63 a Daily gain (%) FCR PCR Feed cost (US$/Kg fish)
» Bioflocs were taken up by fish and degraded biologically. Yet, the amount of bioflocs stayed almost constant. This implies that new flocs are constantly produced (using the excreted N). » The residence time of bioflocs was calculated to be around 8 hours. The flocs seem to be a very dynamic system. » most cells in the flocs are young and active.
» Conventional fish, shrimp ponds 20-25% » BFT Tilapia ponds (Avnimelech) 45% » BFT Shrimpponds (McIntosh) 45% » Closed shrimp tanks (Velasco) 63% » BFT shrimp ponds, 15 N study 18-29% of total N consumption (Michele Burford et al.) * Tilapia, 15 N Study, flocs supplied about 50% of fish protein requirement. (Avnimelech).
» Fish or shrimp growing in BFT systems eat the pellets when applied, but eat bioflocs all the time. » Confirmed in a work done by Albert Tacon with shrimp. » Observations with tilapia. » Effects on lowering of FCR in tilapia production
SPECIAL USES, ADDED VALUES DESERT AQUACULTURE
Effects on propagation Shrimp broodstock grown in BFT have earlier sexual maturity And higher productivity Similar result with tilapia Work by Julie Ekasari Better nutrition? Fatty acids? Hormonal effects?
Fatty acids% Total Fatty Acids Total n Total n Total n LA13.43 ALA0.36 EPA0.56 DHA0.32 AA1.30 n-6 fatty acids is essential for tilapia and its reproduction (Watanabe 1982) Biofloc considerably high in AA (Arachidonic Acid) AA is beneficial for fertilization rates stimulates testicular testosterone in goldfish (Izquierdo et al 2001) Biofloc considerably high in AA (Arachidonic Acid) AA is beneficial for fertilization rates stimulates testicular testosterone in goldfish (Izquierdo et al 2001) Protein : 37 – 46% DW Lipid : 11.9 % DW Protein : 37 – 46% DW Lipid : 11.9 % DW
2. Physiological factors ˃Hormones ˃Morphological changes ˃Mobilization of energy reserves 2. Physiological factors ˃Hormones ˃Morphological changes ˃Mobilization of energy reserves Blood total cholesterol in fish in BFT tanks was higher Cholesterol precursor of steroids hormones Blood glucose as an indicator of mobilization of energy reserves Fish growth
Higher concentration in BFT higher concentration of hormones were involved?
Higher concentration in BFT More energy was mobilized for reproductive activities More energy supply? Higher concentration in BFT More energy was mobilized for reproductive activities More energy supply?
Despite of more active reproductive performance the female in BFT tanks grew better Yet, the fish in BFT required less feed (9.3 vs 8.3 kg/tank) Yet, the fish in BFT required less feed (9.3 vs 8.3 kg/tank)
ab Julie Eskari
» Tilapia fingerlings (120 g) stocked to over- wintering facility on January 4, » Feeding ~ 1% BW » On February 18, they weighed 171 g » Daily growth of 1.16 g/fish » FCR = 0.5
AND SECONDARY INFECTION OF FISH BY STREPTOCOCCUS Total infectedSick fishDead fish Treatment a)Injected fish 112 (2)9 (9) Control 164 (2)12 (3) BFT a)Non- injected fish 11 (4.7) 4 (1.5)7 (5)High exchange 3 (1.4) 1.3 (1.0)1.8 (1.7) ASP High water exchange = 0.5l/min per kg fish (700% per day) BFT< Limited water exchange = 10% per day EFFECT OF WATER EXCHANGE RATE ON PRIMARY Control BFT
Luo and coworkers in China reported Yields of 45kg/m3. Higher production and lower FCR as compared with RAS. Higher concentrations of Superoxide Permutase.
» Cultivo de tilapia en sistemas biofloc es simple, fácil y rentable. Tilapia como filtrador es feliz en esos sistemas. Se ahorra los gastos de alimentación (~ 30%) y comer mejor. Menos enfermedades. Mayor crecimiento y menor FCR. La manera más rápida de iniciar la producción intensiva de tilapia. Si necesita ayuda, estaré feliz de hacerlo: »