What Is Feed?

Feed is recognized as the most costly component of fish farming which constitutes 60-70% of total production costs of tilapia (Oreochromis niloticus) for small-scale, rural farmers in the Philippines (ADB 2005). The cost of commercial fish feeds are rising sharply as the market demand increases to supply growing aquaculture and the availability of fishmeal declines. About 40% of feed costs are attributable to fishmeal, which constitutes 15-20% of the feed formulation. Reductions in both the amount of feed used for grow-out of marketable fish and in the cost of formulated feeds are two approaches to containing feed costs that can effectively increase income for tilapia farmers.

Much of the fishmeal used for tilapia in the Philippines is

1989; Diana 1997). A number of mixed feeding schedules that involved feeding Nile tilapia O. niloticus alternately with high- and low-protein feeds were tested where the fish responded well to some of the mixed feeding schedules (i.e., high-protein feed alternated with low-protein feed) and that fish on mixed schedules exhibited growth performance that was comparable to the performance of fish reared entirely on the high-protein feed. A substantial cost saving on feeds was realized, and the nitrogen loading of the system was reduced by some of these feeding schedules (De Silva 1985, 1989; De Silva et al.

Delayed feeding were observed by starting the supplemental feeding on the 45th and 75th day of culture period while the strategies using satiation levels used a process of feeding to ad-libitum to determine the total amount of feeds that can be consumed and reducing the daily ration to the desired satiation level. For the alternate day feeding, the full ration based on average body weight will be fed to the fish following a schedule of alternate day after the 45th day of culture period.

Within the conduct of the trials, fish sampling was done every two weeks by getting a sample of 50 fish per pond to monitor growth in terms of weight gain and to calculate for the feed adjustment. After the culture period of 120-150 days, the fish stock was harvested totally by seining and complete draining of the ponds. The harvested fish were counted and weighed for the survival and total biomass.

Experimental