Feed conversion ratio is very important in aquaculture industry since this parameter will tell if the feed given to the fish has been utilized efficiently or not. Knowing the FCR of a certain feed used in fish farming could give idea how much feed should be prepared for a certain cropping. Generally, in the aquafeed industry fish feed is expensive which comprise about 60-70% of the production cost hence, keeping track of FCR data together with good aquaculture practices are very critical.
FCR is the amount of feed needed to grow a kilogram of fish. It is calculated as the amount (gram or kilogram) of feed given to the fish divided by the value for fish weight gain (gram or kilogram). Another term related with FCR is FCE or feed conversion efficiency. FCE is just the reciprocal (1/FCR) of FCR. FCR is commonly used in fish farms while FCE for the scientific community. An FCR value closer to 1 (equivalent to 100% FCE) is the most desired value among fish growers. It means almost all feed given to the fish were successfully converted into fish biomass. A sample computation for FCR and FCE is shown below:
Fish are given 5kg diet to exhibit a 4kg weight gain.
Feed Conversion Ratio
FCR = feed given / weight gain = 5/4 = 1.25
Feed Conversion Efficiency
FCE = 1/FCR = 1/1.25 = 80%
FCR/FCE of course could vary among fish species, sizes, environmental parameters, culture system and management. Therefore, it is very important to keep a record of these parameters to better assess the efficiency of the diets. Generally, small sized fish have lower FCR values compared to bigger fish of the same species. It is also possible to attain an FCR lower than 1 especially if natural food is abundant in the culture system. Moreover, aside from being highly efficient, lower FCR values could also mean very minimum waste polluting the water system.