Wednesday December 30 2015

How biotechnology can be used to improve aquaculture

Fish farmers use a net to harvest mature fish

Fish farmers use a net to harvest mature fish from a pond. FILE PHOTO 

By Nasser Kasozi

Aquaculture, the farming of aquatic animals, has been identified by the government as means to improve food and nutrition security and contribute to economic activity and household incomes.
Fish is a priority commodity under Development Strategy and Investment Plan (DSIP) for the agriculture sector.

However, current production of 90,000 tonnes per annum indicated by the ministry of Agriculture does not meet domestic and external market demand, despite the existing potential.
In Uganda, aquaculture faces several challenges, mainly disease outbreaks, poor quality brood stock of fingerlings and domestication challenges, poor quality feeds and water quality management.

A tool to enhance
Aquaculture biotechnology is one of the tools that can enhance aquaculture farming because it encompasses a range of approaches to improve both subsistence and commercial production and management.
Although some biotechnologies are novel, others have a long history of application like fermentation and fertilisation of ponds to increase availability of feed.

Several modern biotechnologies are based on rapidly evolving knowledge of molecular biology and genetics.
But, in Uganda, their application to increase production from aquatic animals lags behind plant and livestock sectors.
However, there are interventions that can boost aquaculture production in terms of feed technologies, disease management, reproduction innovations, holding systems, and pre-market conditioning.

In many parts of Asia, Europe and US, biotechnology has been applied to enhance reproduction and early development success of cultured organisms, as well as expand periods of reproductive cells.
Conserve biodiversity
Genetics also have the potential to satisfy new markets for farmed products, such as specific market tastes.

Likewise, biotechnology may provide avenues for improving the reproductive success and survival of endangered species, thereby helping to conserve aquatic biodiversity.
Transgenic technologies can enhance growth rates and market size, feed conversion ratios, resistance to disease, sterility issues and tolerance of extreme conditions.
In Asia, carp and tilapia fish species are benefiting from genetics research in a number of areas. The Genetic Improvement of Farmed Tilapia project in Asia is a case for examining the genetics of an important farmed fish species.
Molecular techniques help provide accurate information on genetic diversity of natural stocks and allow genetic tagging in breeding programmes.

Production of specific disease free and resistant stocks are two objectives being developed.
Also, immunity stimulation and enhancement are being incorporated into diets to boost protection of the fish species.
Probiotics, which are live bacteria and yeasts that are good for our health, are administered as feed supplements, which affect the host animal by improving the intestinal microbial balance.

More than 15 species of diatoms and green algae are used for first-feeding of hatchery-produced fish. In addition, application of enzymes has been discovered to counteract the anti-nutritional factors of feeds of plant origin, Phytase is one example.
This enzyme helps fish to use the phosphorous available in plant protein-based feeds.

Modify genetics
A significant expansion of tilapia production using indoor systems has also been developed in many countries.
Other interventions as far as pre-market conditioning is concerned are the temporary holding of Bluefin tuna (Thunnus thunnus) to improve meat quality.

Similar techniques have been adapted by fishermen in the Mediterranean holding Atlantic bluefin tuna.
The recent intervention is the Aquadvantage salmon, which is a genetically modified Atlantic salmon.
The purpose is to increase the speed at which the fish grows, without affecting its ultimate size or other qualities. The fish grows to market size in 16 to 18 months rather than three years.

The emphasis on biotechnology and its contribution to food security, poverty alleviation, and income generation especially in the fish sector is increasing.
However, we need to be prepared to address the challenges this will bring, and develop these technologies in a responsible manner.

The author is a research officer, Abi ZARDI/Naro, in Arua.