Aquaculture Feed and Fertilizer Resources Information System

Nile tilapia - Supplemental feeds & feeding

Supplemental feeding compensates for natural food nutrient deficiencies in fertilized ponds and is the usual feeding method for semi-intensive tilapia culture systems. A comprehensive review supplemental feeding practices and of various supplementary feeds is provided by Tacon (1988) and De Silva (1995).  The use of supplemental feeds leads to significant increases in tilapia yield in comparison to fertilized ponds alone. However, farmers must be aware of the complex interactions between the natural food supply and supplemental feeds and that incorrect feeding strategies can lead to financial loss.  Supplemental feeding should be carried out properly coupled with a good understanding of the nutrient content of the various feed ingredients (Table 8). Supplementary feeds can be made up of single ingredients or combinations of ingredients either simply mixed together or powdered and compounded into moist dough before feeding. The most common feedstuffs are agricultural by-products such as rice bran, broken rice and maize with occasional use of grass and leaves. Dry ingredients are normally ground before being dispersed throughout the pond. However, many raw ingredients of plant origin are inappropriate for tilapia fry, but can be used for fingerling and larger fish. It should be mentioned that commercially formulated pellets can also be considered as supplementary feed when used in combination with a pond fertilization regime, or used in combination with cheap feed ingredients.  Some farmers often use formulated feed as a single feed source for a particular life stage.

There are no generalized feeding tables for the use of supplementary feeds in Nile tilapia farming although feed manufactures often provide recommended feeding rates for their feeds.  However, there are some general rules. The population of natural food organisms in the culture system gradually decreases as the standing crop increases such that the amount of supplementary feeds should be gradually increased as the fish grow. Feeding rates should be assessed according to the natural productivity of the ponds and the fertilization program. Thus, if transparency decreases, feeding rates should be reduced. Conversely, if transparency increases, feeding rates and/or nutrient quality (such as protein content) should be increased. Optimal feeding rates and frequency of feeding are site specific and also depends on the various types of supplementary feed items used.  In a detailed profitability analyses of various inputs for pond culture of Nile tilapia in Thailand, Yi and Lin (2000) reported that fertilizing ponds with urea and TSP at 28 kg N and 7 kg P/ha/week, respectively, and supplementing with pelleted feed at 50 percent satiation level starting only when the fish reaches 100 g size, yielded the best economic returns.  Orachunwong et al. (2001) reported that red hybrid tilapia in floating cages fed a 25 percent protein diet three to four times a day resulted in better growth and feed conversion ratio than when fed twice a day.