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Livestock-Based Farming Systems, Renewable  Resources and the Environment

  

Growth of red tilapia (Oreochomis mossambicus) and black tilapia (Oreochomis niloticus) with common carp (Ciprinus carpio) in monoculture and polyculture by using natural feed in ponds fertilized with biodigester effluent

Nguyen Huu Yen Nhi and T R Preston*

An Giang University, 25 Vo Thi Sau St., Long Xuyen City, Vietnam
nhynhi@agu.edu.vn
* TOSOLY, AA 48 Socorro, Colombia.

Abstract

This experiment was carried out in the research farm of An Giang University from November 2011 to February  2012 to compare growth of red tilapia (Oreochomis mossambicus) and black tilapia (Oreochomis niloticus) in monoculture and polyculture with common carp (Ciprinus carpio) in an outdoor natural pond system, using biodigester effluent as fertilizer and duckweed as feed supplement. There were four treatments with three replicates in a completely randomized design with only Tilapia or Tilapia and Common carp (5:1) at 5 fish/m2 in the natural ponds (4m2), seeded with duckweed and fertilized with biodigester effluent.

Growth rates of black tilapia were significant higher than of red tilapia (weight gains were 1.62 and 1.30 g/day, respectively). There was no difference in growth rate of black tilapia compared with red tilapia when both were raised with common carp. Growth rates of common carp were not different between raising with black or red tilapia. Total yield of fish with combined black tilapia and common carp was 7.2 tonnes in 90 days, equivalent to 29 tonnes/ha/year.  The survival rate of fish in the four treatments did not differ. Water quality parameters did not differ among treatments. The concentration of phytoplankton and zooplankton increased during the experiment.

Key words: Duckweed, feed supplement, tilapia, common carp

Table 1. Daily weight gain of red (RT) and black (BT) tilapia and common carp (C) in the experiment (g)

Treat

BT

BTC

RT

RTC

SEM

P - value

Tilapia

1.62a

1.58ab

130b

1.28b

0.69

0.013

Common carp

*

1.24

*

1.14

0.12

0.614

 

Table 2 . Total yield of tilapia and common carp in each treatment

 

BT

BTC

RT

RTC

SEM

P - value

Yield, kg/4m2

2.88

2.9

2.45

2.42

0.186

0.193

Yield, kg/ha*

7192

7245

6118

6044

465

0.193

*In 90 days

 

 

 

 

Table . Total yield of tilapia and common carp in each treatment
  BT BTC RT RTC SEM P - value
Yield, kg/4m2 2.88 2.9 2.45 2.42 0.186 0.193
Production, kg/ha 7192 7245 6118 6044 465 0.193