Site pages
Current course
Participants
General
Topic 1
Topic 2
Topic 3
Topic 4
Topic 5
Topic 6
Topic 7
Topic 8
Topic 9
Topic 10
Topic 11
Topic 12
Topic 13
Topic 14
Topic 15
Topic 16
Topic 17
Topic 18
Topic 19
Topic 20
Topic 21
Topic 22
Topic 23
Topic 24
Topic 25
Topic 26
10.3.Methods of feed formulation
Unit 10 - Methods of feed formulation and manufacturing
10.3.Methods of feed formulation
10.3.1.Pearson square method
In most fish diets, protein is the most expensive portion and is usually the first nutrient that is computed in diet formulation. The energy level of the diet is then adjusted to the desired level by addition of high energy supplements which are less expensive than protein supplements.
The Pearson square method is an easy way to determine the probable ratios of mixing different protein ingredient and to formulate a feed with desired dietary protein level.
For example, consider rice bran (with 8.2% protein) and soybean meal (with 44% protein) were available as feedstuffs to prepare a diet for carp with 27% protein, a square is constructed and the two feedstuffs with their protein values are put on the two left corners along with the protein content of each ingredient.
The desired protein level (27%) of the feed is placed in the middle of the square. Next, the protein level of the feed is subtracted from that of the feedstuffs, placing the answer in the opposite corner from the feedstuff. Ignore positive or negative signs.
Thus to make the 27 percent crude protein of carp feed, we must mix 17/35.8 of rice bran and 18.8/35.8 soybean meal.
Now, we have to calculate the proportion of mixing the ingredients by weight in relation to their protein content. This could be elucidated as given below.
That is, for the preparation of 100 kg of fish feed with 27 percent protein, 47.50 kg of rice bran and 52.50 kg of soybean meal are to be mixed.
If more than two feedstuffs are used in a feed, they may be grouped into basal feeds (CP < 20 percent) and protein supplements (CP > 20 percent), averaged within each group, and plugged into the square method. For example, suppose shrimp meal and corn were also available for the carp feed mentioned above. The crude protein levels of the shrimp meal (52.7 percent) and of corn (10.2 percent) are averaged with soybean meal and rice bran, respectively.
Basal feed = (21.35/39.15) x 100 = 54.53%
Protein supplement = (17.8/39.15) x 100 = 45.47%
Thus, to make 100 kg of this feed one would mix the following:
Rice bran 27.265 kg
Corn 27.265 kg
Soybean meal 22.735 kg
Shrimp meal 22.735 kg
The square method is helpful to novice feed formulators because it can get them started in diet formulation without the need to resort to trial and error. The square method can also be used to calculate the proportion of feed ingredients to mix together to achieve a desired dietary energy level as well as a crude protein level.
10.3.1.Pearson square method
In most fish diets, protein is the most expensive portion and is usually the first nutrient that is computed in diet formulation. The energy level of the diet is then adjusted to the desired level by addition of high energy supplements which are less expensive than protein supplements.
The Pearson square method is an easy way to determine the probable ratios of mixing different protein ingredient and to formulate a feed with desired dietary protein level.
For example, consider rice bran (with 8.2% protein) and soybean meal (with 44% protein) were available as feedstuffs to prepare a diet for carp with 27% protein, a square is constructed and the two feedstuffs with their protein values are put on the two left corners along with the protein content of each ingredient.
The desired protein level (27%) of the feed is placed in the middle of the square. Next, the protein level of the feed is subtracted from that of the feedstuffs, placing the answer in the opposite corner from the feedstuff. Ignore positive or negative signs.
Thus to make the 27 percent crude protein of carp feed, we must mix 17/35.8 of rice bran and 18.8/35.8 soybean meal.
Now, we have to calculate the proportion of mixing the ingredients by weight in relation to their protein content. This could be elucidated as given below.
That is, for the preparation of 100 kg of fish feed with 27 percent protein, 47.50 kg of rice bran and 52.50 kg of soybean meal are to be mixed.
If more than two feedstuffs are used in a feed, they may be grouped into basal feeds (CP < 20 percent) and protein supplements (CP > 20 percent), averaged within each group, and plugged into the square method. For example, suppose shrimp meal and corn were also available for the carp feed mentioned above. The crude protein levels of the shrimp meal (52.7 percent) and of corn (10.2 percent) are averaged with soybean meal and rice bran, respectively.
Basal feed = (21.35/39.15) x 100 = 54.53%
Protein supplement = (17.8/39.15) x 100 = 45.47%
Thus, to make 100 kg of this feed one would mix the following:
Rice bran 27.265 kg
Corn 27.265 kg
Soybean meal 22.735 kg
Shrimp meal 22.735 kg
The square method is helpful to novice feed formulators because it can get them started in diet formulation without the need to resort to trial and error. The square method can also be used to calculate the proportion of feed ingredients to mix together to achieve a desired dietary energy level as well as a crude protein level.
Last modified: Tuesday, 30 August 2011, 9:05 AM