Abstract
VAC systems are an integration of garden (vuon), pond (ao) and animal pen (chuong). VAC farming systems can be classified into different types on the basis of the uses and intensity level of orchard and pond. Fruit trees include citrus, longan, mango and sapodilla, and vegetables include cassava, centella, sweet potato and water spinach. Livestock are poultry and/or pigs. A fish polyculture is practised with species such as silver barb (Barbonymus gonionotus), Indian major carps (mrigal, Cirrhinus cirrhosus, and rohu, Labeo rohita), silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon idella), giant gourami (Osphronemus goramy), river catfish (Pangasianodon hypophthalmus), hybrid catfish (Clarias macrocephalus × C. gariepinus), common carp (Cyprinus carpio), kissing gouramy (Helostoma temminckii) and Nile tilapia (Oreochromis niloticus). Pig manure is commonly used as fertilizer for crops while rice by-products are mainly used to feed the livestock. Major inputs for ponds are on-farm resources (crop residue, grass, fallen fruit, rice by-products, human waste, poultry manure, urine and washing from the pig sty) for the low input systems, and off-farm feeds (trash fish, fish meal, golden snail) for medium and high input aquaculture systems. Fish production is below 2 t ha-1 year-1 in the low input and 2-10 t ha-1 year-1 for medium and high input aquaculture.In general, VAC farming in the Mekong Delta is practised in a medium farm with an average pond area ranging from 500 to 1,000 m2, producing fish at less than 1 t yr-1, of which about 250 kg is for family consumption and the surplus, if any, for sale is insignificant. As VAC still has many problems and constraints, an appropriate way to develop VAC farming in the Mekong Delta is to provide farmers with farm component technologies and management knowledge.
Cryoprotective Effects of Protein Hydrolysates Prepared from By-Products of Silver Carp (Hypophthalmichthys Molitrix) on Freeze-Thawed Surimi