Biofloc Systems, Tilapia by Product may Support Cheaper Shrimp Production

Tilapia processing waste may provide an alternative and less\r\nexpensive protein source to use in place of fishmeal in shrimp feeds while\r\nsupporting shrimp production, Brazilian researchers say.

A team of researchers from the Semi-Arid Rural Federal\r\nUniversity (UFERSA) and Santa Catarina State University in Brazil explored the\r\nuse of tilapia processing waste silage (TPWS) in the diets of farmed shrimp\r\nraised in clear water (CWS) or biofloc systems (BS).

The researchers published their findings in the journal, Aquaculture and Fisheries​​​.

“The aim of this study was to evaluate the inclusion of\r\ntilapia processing waste silage (TPWS) in diets for L. vannamei juveniles\r\nreared under clear-water and biofloc conditions,” ​they said.

Also read: Evaluating Compensatory Growth in Pacific White Shrimp in a Biofloc System

The researchers found that survival was above 80% for shrimp\r\non all diets and in both production systems. However, the inclusion of TPWS in\r\nthe diets did not alter shrimp performance.

Shrimp final weight and SGR were altered by the production\r\nsystem used, but not by the diet, they said. Shrimp in the biofloc system\r\noutperformed those in the CWS.

“In our experimental conditions, the inclusion of tilapia\r\nprocessing waste silage (TPWS) in L. vannamei diets was possible up to 6%\r\nwithout compromise shrimp performance and survival,”​ the researchers said. “In\r\naddition, shrimp raised in BS demonstrated better growth performance as\r\ncompared to CWS.”​

Interest in biofloc production​

There has been great interest in exploring the production of\r\nPacific white shrimp (L. vannamei) in biofloc systems, the researchers said.\r\nDisease outbreaks and low productivity prompted inquires into alternative\r\nproduction systems to boost shrimp growth and production efficiency.

Biofloc production or biofloc technology (BFT) allows for\r\nthe production of large amounts of shrimp on a per area or per volumes basis\r\nand has little to no water exchange, they said. The system allows for improved\r\nbiosecurity, practically for farms in regions with a concentration of\r\naquaculture production sharing a water supply.

“BFT has gained popularity because it offers a practical\r\nsolution to maintaining water quality and recycle feed nutrients\r\nsimultaneously,” ​they said. “Another advantage of the biofloc system is the\r\npossibility to use alternatives low protein diets and consequently, decrease\r\nthe production costs; mainly due to the continuous availability of natural food\r\nsource in a form of live microorganisms.”​

Also read: Intestinal Bacteriome of Pacific White Shrimp in Biofloc, Clear Water Systems

Why feed tilapia processing waste silage?​

Use of fishmeal is unsustainable and the feed ingredient is\r\none of the most expensive to include in aquaculture diets, the researchers\r\nsaid. The aquaculture industry is interested in limiting or replacing the\r\ningredient.

However, there have been problems found with some of the alternative\r\ningredients adopted including a lack of some essential amino acids,\r\ndifficulties with palatability and digestibility and the inclusion of\r\nanti-nutritional factors, they said. But, there have been some successful\r\nalternatives found for use in shrimp diets, including plant-based protein\r\nsources and use of mineral supplementation.

“Fish silage can be produced using fisheries and aquaculture\r\nprocessing residues,” ​they said. “Fish silage is an alternative protein source\r\nto the fishmeal and posses a simpler and cheaper production method.”​

Additionally, using fish silage as an alternative protein\r\ningredient in aquafeed helps address “environmental and sanitary problems,” ​stemming\r\nfrom inadequate waste disposal of fish reside, they said. Adding, “It is also a\r\nway of decreasing the feeding costs, and, consequently, the production costs\r\nsince feeding corresponds around of 60% of the overall expenses.”​

“Tilapia is a worldwide relevant species for aquaculture\r\nindustry and has demonstrated positive results as a fish silage incorporated\r\ninto diets due to its nutritional quality,”​ the researchers said. However,\r\nthere is no information about the use of TPWS with shrimp in a biofloc system,\r\nthey added.

Feeding trial details​

During the feeding trials, juvenile L. vannamei were raised\r\nat a 63 shrimp/m2 density in either a biofloc or clear-water conditions for 45\r\ndays and received one of five diets, the researchers said.

The diets for both systems were isocaloric and isoproteic\r\nincluded a varying level of tilapia silage (TPWS) at 0, 1.5%, 3%, 4.5% and 6%\r\ninclusion, they said. The biofloc used was formed prior to the feeding trial.

The TPWS was generated using Nile tilapia filet residue\r\nincluding “head, bones, skin, fins and viscera,”​ the said. Acid silage was\r\ngenerated, dried, ground and the pH neutralized before using in trial diets.

“In regards to proximate analysis, the results demonstrated\r\nthat TPWS contained 83.8% dry matter, 33.7% crude protein, 37.4% crude lipid,\r\nand 21.5% ash based on dry matter,”​ they added.

Water quality measures were monitored twice daily, and all\r\nshrimp were weighed at the start and end of the experiment, the researchers\r\nsaid. Final body weight, specific growth rate (SGR), survival and feed\r\nconversion ratio (FCR) were determined.

Also read: Ten Easy Steps Towards Biofloc Production of Shrimp or Tilapia

Results​

Overall, no interactions were found between the system and\r\nthe diet, the researchers said. Survival remained above 85% for all diets and\r\nsystems.

FCR was lower for shrimp in the biofloc system, they said.\r\nAverage final weight and SGR were altered by the system, but not the diet used,\r\nand were higher for shrimp in the biofloc program.

However, shrimp receiving the highest amount of TPWS did\r\ntend to have the highest final weight and the largest SGR, they said.

“Both biofloc (BS) and clear-water (CWS) systems, tilapia\r\nprocessing waste silage (TPWS) could be included at the highest level (6.0%)\r\nwithout losses in growth performance and survival,” ​the researchers said. “On\r\nthe other hand, in BS condition shrimp presented the best performance as\r\ncompared to CWS, probably due to the continuous availability of natural food.​

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“This natural productivity is normally present in a form of\r\nbacteria, microalgae, protozoa, nematodes, copepods and rotifers,” ​they added.\r\n“These microorganisms are a rich source of lipids, vitamins and essential amino\r\nacids, as well as highly diverse ‘native protein.’”​

Source : Feed Navigator