Utilization of natural feed for growth and survival enhancement of Penaeus monodon juveniles in culture system and its effects on water quality
Shrimp feeds on the natural organisms such as plankton, bacteria and benthos. Problems in shrimp farming are due to pollution, diseases and poor feeding practices. There are several advantages in improving natural food in shrimp farming. First, water quality is very much improved since the oxygen...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2000
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/9099/1/FSAS_2000_24%20IR.pdf |
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| Summary: | Shrimp feeds on the natural organisms such as plankton, bacteria and
benthos. Problems in shrimp farming are due to pollution, diseases and poor
feeding practices. There are several advantages in improving natural food in
shrimp farming. First, water quality is very much improved since the oxygen
evolved in photosynthesis is used in aerobic decomposition of organic matter.
Moreover, ammonia in the water are reduced due to uptake by algae. Secondly,
the digestibility and acceptability of natural food by shrimp have been well
established. Understanding the contribution of natural foods in the shrimp
culture system may help to increase the production and reduce the cost of farming. This study was carried out to demonstrate the importance of natural
food in intensive shrimp culture system. Analysis of composition and
abundance of macrobenthos in shrimp culture ponds was done by sampling the
sediment from six different locations of two shrimp ponds. Gut content analysis
was also performed to assess the fullness of shrimp gut. A significant negative
correlation (r =-0.97, p<0.05) was also observed between the gut content and the
abundance of macrobenthos in the pond bottom. There was a decline in the
fullness of the shrimp foregut with the reduction of benthic populations in the
pond sediments, probably indicating the importance of benthos as food for
shrimp in culture system. In another field experiment the effect of bacterial
product on development of benthic community in shrimp ponds, was
determined. The density of polychaetes and insect-larvae was significantly (p<
0.05) higher in ponds with commercial bacteria products than the control, and
also showed better feed conversion ratio (FeR). Laboratory experiments showed
that the growth rate of P. monodon juvenile was significantly (p< 0.05) higher
when fed with the combination of natural and artificial diets than other
treatments. Survival rate was also significantly (p< 0.05) higher in those shrimp
fed on natural diet compared to the others. The presence of bottom sediment
significantly (p< 0.05) increased the survival rate of the shrimps. Shrimps fed
with artificial diet showed significantly higher excretion of ammonia compare to
the others. The results showed that unicellular algae could help shrimp to attain
high growth and survival rates. In addition these algae control the water quality
parameter such as ammonia-N and nitrite-No Tanks without shrimp showed
significantly lower (p <0.05) rate of nitrogen change compared to the rest of the treatments, indicating that most of the nitrogenous source was from the shrimp
excretion. There was no significant difference among the ingestion rates of three
algal species but was relatively high with Chaetoceros calcitrans and low with
Tetraselmis tetrahele. The results indicated that Penaeus monodon juvenile was able
to ingest and digest the unicellular algae. Feeding with natural feed enhanced
the non-specific immune system of the shrimp. The results showed that feeding
on chironomid larva significantly (p<O.05) increase the survival rate when
shrimp was exposed to the white spot virus (WSV).
The results of this study showed that natural food play an important role
in shrimp farming. The presence of suitable natural food may enhance the
growth and survival of shrimps in a culture pond and improve the water and
sediment quality. This study suggested that the optimum growth of shrimp
could be obtained by the right combination of natural and artificial diets. |
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