HOW TO DETERMINE THE FEED CONVERSION EFFICIENCY, FEED CONVERSION RATIO AND GROWTH RATE OF YOUR FISH

WHAT IS FCE & FCR

As a fish farmer, there are two important parameters that you can use to determine the performance of your fish and the feed you are using to feed them, these two parameters are Feed Conversion Efficiency, FCE, and Feed Conversion Ratio, FCR. Food conversion efficiency, FCE is the ability of the fish to convert the feed eaten to body flesh or weight, while feed conversion ratio, FCR is the difference between the actual quantity of feed eaten by the fish and the equivalent weight it gained over a given period of time; for example, from stocking to harvest.

The FCE is dependent on the quality of the fish, (fingerlings/juveniles) stocked and the condition or environment it is raised while the FCR is primarily a function of the quality of the feed and to some extent the quality of the fish, (fingerlings/juveniles) stocked and the condition or environment it is raised. A good percentage of every quantity of feed given is expected to be converted by the fish into body weight. However while in some cases this might be the case, in mainly others, this is not. Hence it is very important for you to monitor the growth rate, food conversion efficiency and food conversion ratio of your fish, right from the beginning. This is how to go about it.

How to determine the fish growth rate

The growth rate is an expression of the feed conversion efficiency and feed conversion ratio. The feed conversion ratio in particular gives you an idea as to what to expect at harvest. Ordinarily, it should be consistently not less than 0.9; and how do you ensure this?

Beginning from the first day of feeding, take a record of all the feed you bought and fed to them up to the day of harvest and sales. The record here relates to the quantity (weight) of feed bought and their cost price over time. This is a very important aspect of commercial catfish farming as it will enable you to determine whether you made profit or loss. On a monthly basis, you can get a sample population of your fish.  To determine the food conversion efficiency and food conversion ratio of the fish, divide the total weight in kilogram of the feed given to them within the month by the real weight gained by the fish within the month. If the figure obtained is 0.9 or below, the FCE is high and FCR low.

For example you bought 2,000 catfish juveniles with an average weight of 8g and a total weight of 16,000 grams: 2000 X 8  (16 kg) and after 1 month of stocking and feeding with 15kg, (15,000 grams) of feed, a sample population of 100 fish weighing 1400 grams (1.4kg) fishes were collected and based on calculations (1400g ÷ 100) a new average weight of 14g was recorded. The FCR will now be calculated thus

Initial estimated total weight                   =          2, 000 x 8g   =   16,000g or 16kg

Current estimated total weight                 =         2, 000 x 14g =   28,000g or 28kg

Current Estimated weight gain                 =         28,000g – 16, 000g =     12,000g

FCR     = Food Quantity Fed                  =         15,000g  = 1.25: 1

   Estimated Weight Gained                    12,000g

Or for easy understanding: 12,000 ÷ 15, 000 = 0.8: This figure paints a picture of 1kg feed being converted to 0.8kg (800g) of fish weight

On the other hand, the figure, 1.25: 1, means that for every 1.25kg of feed consumed by the fish, they were able to convert it to only 1kg of weight of flesh or fish weight. This is fair but it did not meet the minimum expectation. As such it needs to be improved upon. For most floating feeds, the projected FCR is between 1 to 1 and 1.11 to 1. That is between 1kg feed weight to 1kg fish weight  and 1.11 kg feed weight to 1kg fish weight. You should strive to attain this by following the laid down recommendations in the manual.

If the above monthly calculation is not feasible for you, you may decide to opt for the post-harvest calculation of your FCE; and this is how to go about it. Before you stock your fingerlings/juveniles, pour them in a sieve to drain water from them. Thereafter, weigh them on a scale, write down the figure obtained on your record book and pour the fish into the rearing tank/pond.

Beginning from the first day of feeding, take a record of all the feed you bought and fed to them up to the day of harvest and sales. In order for you to determine the FCE, you should first deduct the fish weight you recorded prior to stocking from the total weight obtained at harvest. There after divide this figure with the total quantity of feed that you fed them. What you get is a reflection of the performance of both the fish and the feed given them. Ordinarily, following the recommended or standard feed conversion ratio of most feed; especially floating feed, any figure you obtain that ranges from 0.9 to 1.0 is assumed to be good; and this should be your target. Anything below 0.9 is not good.

Please note that one very importance of this calculation is that right from beginning it will provide you with vital information that may determine the direction and eventual outcome of your investment. Irrespective of the figure obtained on a monthly basis, you should keep on improving on it, by working on the major factors that determine the FCE & FCR.

HOW TO IMPROVE THE FCE & FCR

a.                   Make sure that your water is not at any time polluted; that is smelling

b.                   Your water pH should be between 6.5 and 9. If lower, add sodium bicarbonate to the water

c.                   Reduce your stocking rate by 20%. Spread fish to other empty tanks/ponds

d.                   In addition to a 70% water change every 2 days, do water flow through rate each next day after the water change at rate of 2 litre per minute for 3 - 5 hours.

e.                   Make sure that the feed crude protein level is within the earlier recommended range. Add good growth promoters like superliv, fish premix, spirulina, etc to the feed if you are producing it by yourself.

f.                    Minimize stress and eliminate conditions that can lead to disease outbreak. Treat diseases before they become troublesome.

g.                   Make sure that the fish is properly sorted and graded.

h.                   Enough quality feed should be provided and feeding schedule maintained.

In our next discussion we are going to consider how to prevent and manage catfish diseases when they do occur.

Please be reminded that the information as contained herewith is based on the climatic and environmental conditions in Nigeria, which is a tropical country. Meanwhile, I will be quick to add that this article is an excerpt from the operational manual for commercial catfish farming titled AN ILLUSTRATED STEP BY STEP GUIDE TO COMMERCIAL CATFISH GROW OUT FARMING, also written by the author since 2003 now updated up to 2015. It will be useful to you; a beginner or an experienced farmer as a working and reference document. The soft copy (to be sent via email) cost 4,000 naira, while the hard copy (to be sent via courier) goes for 6,500 naira. If you are interested please call: 08023620926; 09030301242 or send email to: festus.okpako88@gmail.com; festus,okpako@yahoo,com or foodscienceng@gmail.com

PAYMENT DETAILS: Festus Okpako, first bank current account number 2006146470

Other available manuals:

# AN ILLUSTRATED STEP BY STEP GUIDE TO COMMERCIAL CATFISH HATCHERY FARMING. PRICE: 6,000 naira (soft copy); 8,000 naira (hard copy)

# A COMPREHENSIVE GUIDE TO COMMERCIAL CATFISH DISEASE MANAGEMENT

 PRICE:4,000 naira (soft copy); 6,000 naira (hard copy).

Please be reminded that all SOFT COPIES will be sent via email and HARD COPIES, via courier,