Particularly when raised in intensive aquaculture, African catfish is an enormously fast growing species. It has been reported, that 40 to 60 day s are needed to grow fry to 20 g. After that, the grow- out stage begins, where the fish requires 90 to 120 days to reach 1 kg (Figure 1). Clearly , the desired harvest weight can be reached earlier when farming inputs promote the growth potential of African catfish. Among other factors, feed quality plays a key role here.
Feed raw material quality
Raw material selection and quality are important factors for producing highly palatable and digestible feed . Imbalances in nutrient composition affect the water quality of the fish housing unit . For example, feeds leading to high feed conversion ratios will result in high amount of feces. The feces of African catfish are unstable and difficult to filter from the water. Given relatively low water exchange rates and high fish biomass per cubic meter, feces disintegrate into many small particles and pollute the water body. Although African catfish can gulp air from the surface, a filled digestive tract and high biomass together with inappropriate environmental conditions can cause high and sudden mortalities on the farm.
Physical feed quality
Physical quality of feed for African catfish refers to feed floatability, level of dust and fines, even pellet size and hardness as well as other parameters . These physical parameters can contribute to optimal feed intake and feed conversion efficiency. Especially feed wastes through uneaten feed , dust and fines negatively impact water quality and will eventually lower the farming success.
Summary
Due to the fast growth of African catfish, it can be quickly demonstrated, that high-performance feed of stable nutritional and physical qu ality enables faster fish growth and gives fish ready for the market in about 130 to 180 days. Popular feeds in African markets are fit for intensive fish farming and thus enable the farmers to utilize the growth potential of African catfish in the most economical way.