Luận án Tiến sĩ: Evaluation of Locally Available Feed Resources for Striped Catfish (Pangasianodon hypophthalmus)

This thesis investigated and compared inputs and outputs, economic factors and current feed  use  in  small-scale  farming  systems  producing  striped  catfish  (Pangasianodon hypophthalmus) in the Mekong Delta. The nutrient content of locally available natural feed  resources  for  striped  catfish  was  determined  and  growth  performance,  feed utilisation  and  body  indices  were  analysed  in  pond-cultured  striped  catfish  fed  diets where fish meal protein was replaced with protein from local feed resources.

 

  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%  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, roundnut cake, broken rice, shrimp head meal, golden apple snail and catfish by-product meal and earthworm meal, whilst the digestibility was in lower 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%), indicating high protein quality of these feedstuffs. In general, the AD of individual EAA 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 DM/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.