2012-12-20
Local feeds suitable for Striped catfish cultivation in Vietnam
Striped catfish pond culture in Vietnam. Photo: Chau Thi Da
Fishmeal in the feed to Striped Catfish in Vietnamese aquaculture can be replaced with locally produced feedstuffs and by-products without negative effects on production. This is the conclusion in a dissertation by Chau Thi Da at the Swedish University of Agricultural Sciences.
A large part of the population in the Mekong Delta of Vietnam is dependent of agriculture and most of the land is used for crop production. To provide food and high quality animal protein to the increasing population, other products than those which can be used as food for humans must be used as feed for fish. Freshwater striped catfish (Pangasianodon hypophthalmus) is a Pangasiid species of high economic value for fish farming in South-East Asia. Although soybean meal has been used in striped catfish feed as a replacement for fish meal, trash fish (marine origin) and fish meal are still the main dietary protein sources for striped catfish, comprising 20-60 per cent of the feed. However, using fish meal is not a sustainable long-term feeding strategy and it will lead to the decline or extinction of some trash fish species.
In his PhD project Chau Thi Da studied different feedstuffs that could be used as alternatives to fish meal or trash fish when Striped Catfish is produced. A survey showed that around 15 feed ingredients are used in striped catfish pond culture in the region. The combination of feed ingredients used in farm-made feeds varied among fish farms. The cost of producing 1 kg of fish using farm-made feeds was usually 8-10 per cent lower than that of using commercial feeds. Digestibility trials on selected potential feedstuffs showed that the apparent digestibility (AD) of DM, CP, OM and energy was highest in soybean meal, groundnut cake, broken rice, shrimp head meal, golden apple snail and catfish by-product meal and earthworm meal, whilst the digestibility was lower in cassava leaf meal and sweet potato leaf meal.
The average digestibility of most essential amino acids (EAA) in selected feed ingredients was high (range 70-92 per cent), indicating high protein quality of these feedstuffs. In general, the apparent digestibility of individual essential amino acids was high for all diets except those with cassava leaf meal, rice bran and earthworm meal, where the AD of EAA was reduced. Two different growth experiments with the same diet (20-100% replacement of fish meal) were performed in an indoor and an outdoor culture system. A significant finding was that daily weight gain (DWG) was much higher (3.2 to 6-fold) in outdoor culture conditions compared with indoor. Feed conversion rate and feed utilisation were also 0.2-0.7 units (kg feed dry matter/kg weight gain) higher in the outdoor system.
The results suggest that fish meal protein in feed for striped catfish fingerlings can be replaced with protein from locally available plant and animal ingredients without compromising growth performance, feed utilisation or carcass traits. By using locally produced ingredients and mainly by-products, small-scale fish farmers can produce a balanced fish feed to a lower cost than commercial feed. This would also lead to a more sustainable fish production since fish meal or trash fish can be excluded from the diet and by the fact that by-products to a larger extent would be recirculated.
MSc Thi Da Chau, Department of Animal Nutrition and Management, SLU, Uppsala, defended his thesis Evaluation of locally available feed resources for Striped catfish (Pangasianodon hypophtalmus) on December 18, 2012. The opponent was Nguyen Thanh Phuong, Can Tho University, Vietnam.
More information
Chau Thi Da, chau.thida@gmail.com
Link to the thesis (pdf):
http://pub.epsilon.slu.se/9259/
Written by:
David Stephansson