ZOOTECHNICAL PERFORMANCE OF COBIA (Rachycentron
canadum) SUBMITTED TO DIETS BASED ON RESIDUE OF THE
FERMENTED SARDINE
INTRODUCTION
One of the limiting factors of cobia marine fish farming is pellet feed
dependence of high protein and lipid. This leads to high cost diets, decreasing
profit of creation (Sanches et al., 2008). On the other hand, there is large
supply of byproducts of fish processing with high nutritional value, but there are
few studies that demonstrate the feasibility of using these utilization in fattening
marine fish. The objective of this study was to evaluate different methods of
conservation of the residue of the fermented sardines (Sardinella brasiliensis)
and its use as a diet for cobia.
MATERIAL AND METHODS
Thirty cobia were used (230.0 ± 20.1 g and 33.0 ± 1.8 cm), distributed in three
tanks of 3000 liters with recirculating seawater system (salinity 35) , density ten
fish per tank, undergoing three diets, were used: T1: fish residue homogenized,
T2: fish residue homogenized plus Trinken (0.1%) and T3: fish chemical silage
(3.5% glacial acetic acid). Clostridium spp, Thermotolerant coliforms, Salmonella
spp, Total count of mesophilic bacteria and molds and yeasts, according to
Downes and Ito (2001) and proximate analyses (Moisture, total protein, ash and
lipids) were based on the procedures set by AOAC (1997). Fish were fed twice a
day for 60 days. Water parameters (oxygen, salinity, pH, temperature, ORP,
conductivity, and ammonia) were monitored daily, mortality rates and food
consumption too. Quantitative data were subjected to analysis of variance
(ANOVA) and comparison of means by Tukey test (P <0.05).
Erika Fabiane FURLAN 1,3
Leandro Amaral HERRERA 2,5
Luciana Yuri SATO 4,5
Francisco da Costa SILVA 2,5
Thais Moron MACHADO 1,3
Eduardo Gomes SANCHES 3,5
1
Centro APTA do Pescado Marinho, Instituto de Pesca, Apta, SAA-SP
Av. Bartolomeu de Gusmão, 192, Ponta da Praia, Santos-SP , Brazil. CEP 11030-906. [email protected]
2 Master's Instituto de Pesca
3 Scientific researcher
4 Veterinary
5 Núcleo de Pesquisa e Desenvolvimento do Litoral Norte, Instituto de Pesca, APTA, SAA.
TABLE 1. Zootechnical performance of cobia subjected to different diets (T1:
residue of fish in nature, T2: fish residue plus Trinken and T3: Silage chemical
residue).
Parameters
Weight final (g)
Weight daily (g/day)
Feed conversion
T1
T2
T3
425.3 ± 18.6
310.7 ± 28.6
345.0 ± 27.4
2.9 ± 1.2
2.9 ± 1.8
3.6 ± 0.8
4.1
Figure 3. Weighing the digestive tract
7.3
6.2
Figure 4. Fedding
DISCUSS
Figure 1. Placing chip for individual marking
Figure 2. Evaluation of growth performance
RESULTS
Results for final weight and average daily gain were significantly higher for fish
fed the T1 diet compared with the other (Table 1). The feed conversion ratio,
shows the rate of feed efficiency obtained with residue in nature resulted in a
very attractive value considering it is a diet with high moisture. Diets were
presented in accordance with value of tolerance limit for microbiological
standards, suggesting that technologies used result in adequate sanitary
products. The recirculation system seawater was used to keep water efficiently
with low solids in suspension even during daily diet.
The results indicated that fish fed residue in natura showed better growth
performance, exhibiting higher weight gain daily and final weight compared to
other treatments. Feed conversion ratio shows the rate of feed efficiency
obtained with residue in nature resulted in a very attractive value considering
it is a diet with high moisture.
It could be concluded that use a diet of waste of the salty sardine process is
suitable for feeding cobia, being promising alternative to use of such residue.
REFERENCES
SANCHES, E.G.; SECKENDORFF, R.W.; HENRIQUES, M.B.; FAGUNDES, L.; SEBASTIANI,
E.F. 2008 Viabilidade econômica do cultivo do bijupirá (Rachycentron canadum) em sistema
off shore. Informações Econômicas, 38(12): 42-51.