Isonitrogenous and isocaloric diets simply refer to two or more diets which have the same nitrogen and caloric content, respectively. 

How to formulate diets that are both isonitrogenous and isocaloric? Try and error? 

Khalil, to formulate feed is very easy but you must have the knowledge of the feed ingredients to use, you must know the nutritional requirement of the animal- be it fish , poultry etc, you must know what each feed ingredient is lacking, you need to know the growing phase of the animal, all these and others will make you to arrive at the nitrogen-protein and energy -calorie of the feed compounded. If u need more tutorial call me. Thanks- Dr Silas Abel

Iso- is the meaning of one and the same. Usually, in one trial where there are two or mor e groups with different composition of the daily ration, they have to be isonitrogenous and isocaloric, because this is the background to compare final results obtained.

Hello,

You get your answer about what these diets are. However, about the formulation, you should say which diets you wish to prepare. If you want to study the effect of micronutrient in diets, you can formulate a routine diet as basal. Just you should use filler (e.g. cellulose) in it. For example if you want to study the effect of 0, 0.1, 0.2, and 0.3 % vitamin C, you should have about 0.5 % cellulose in the basal diet. Then, you should replace cellulose by the aformentioned levels of vitamin C. Then you have 4 diets similar each other, except for vitamin C and cellulose. Vitamin C and cellulose do not affect the diets energy or nitrogen.

Khalil, the way you asked the question, I think you are not interested in comparing diets. Are you interested in making a balanced diet?

The use of linear programming in a simple spreadsheet, you can find the optimal combination of feed ingredients (cheaper) if determined energy levels and protein requiring animals at every stage of your life.

As for your question, how do isonitrogenous and isocaloric rations? The answer is that it can be done by trial and error, but using some software to rations would be much faster.

Hi all,

Sebastian, I want to compare diets made from different samples from the same treatment with different level of replacement. ie: 10%, 20%, 30% & 40%. As for know, I've learnt to use the Box method. Can I use this method to do the isonitrogenous and isocaloric feeds? 

Seyyed, I want to study the effect of different protein sources in the diets. Thus, different level of the sources in the feed will affect the diets right? 

Dr. Silas Abel, can you give links for the winfeed 2,.8 software tutorials? I've been looking in youtube but can't find anything related to it. However, some of the youtubers did show tutorials on how they calculate the feed ingredients by using their own method. 

Petkova, thanks for the info. That is why i want to learn on how to formulate the isonitroenous and isocaloric feed.

Hi, yes. Your case is a little complicated, because you are trying to manipulate macronutrients. In this case, you should first determine all feedstuffs protein, lipid and energy. Then, you may need a concentrate source of protein (e.g. gluten of casein), lipid (plant and fish oil) and carbohydrate (it is better to use dexterine or alpha starch; but wheat meal may work well). Now, you should change the percentages of feedstuffs in the diets to reach similar protein and energy levels. It is better to balance lipid and carbohydrate beside energy, however, in small variation in lipid and carbohydrate can be negligible in iso-energetic diets. Use of diet formulation software nay facilitate your work and calculations.

Kalil, I'm not sure that is the Box method. I think it must be the one I know as "Pearson Square". If you make reference to the Pearson Square method; yes you can use for this purpose, but you must keep in mind that this method is limited to 2 ingredients. That is why usually other calculation methods used to balance rations.

I hope to answer your question.

Regards, Sebastian

You can use the Pearson Sqaure for more than to 2 ingredientes, but is complicated. It is more easy  using a spreadsheet with solver complement in Excel. I understand you need to formulate two or more diets with different ingredientes or ingredient levels but the same protein and energy content. I can help you, I know how to use the winfeed software and also the solver complement. Send me an e-mail beltran1979 in hotmail.

isonitrogenous are the diets where the nitrogen or the protein source is the single ingredient only and isocaloric diets are the diets where you rely for energy only on single ingredient.e.g.if you are using calona meal as the only source of nitrogen in your diet thats called isonitrogenous diet.

People these  kind of formulations even for the growth trials in fish.but i dont think so it is a good way to evaluate the ingredients.but for the digestibility trials it is ok.

Most of the comments are right.

Hi all,

Seyyed, thanks for the suggestions. Will look for it. :)

Sebastian, yup the "Pearson Square". I just need to balance the rations to achieve iso-feed? Thank you for the suggestion.

Beltran, thank you. Will contact you via email after this. 

Zulkernain, in my case, I want to evaluate the ingredients level in the feed. Do I need to do isonitrogenous feed? Can I do digestibility trials too with the same feed which is not isonitrogenous? 

Alireza, yup.

Isonitrogenous diets are those where the concentration of nitrogen is the same. Does not matter if you change the source. The same meaningful is true for isocaloric diets, it means diet with the same contend of energy. The reason you have to keep the diets iso when are evaluating feedstuffs is to see the effect of it, instead the effect of different levels of protein or energy.

Thank you Marco Bomfim. Now I get the picture when you said instead the effect of different levels of protein or energy, I actually need to study the feedstuff itself whether it is suitable for animal feed or not. 

Hi,

My contribution may have come late but I hope it would be worth it. As others have already said iso-nitrogenous and -caloric diets have similar protein and lipid/fat contents. This may lead to iso-energetic (didn't mean to introduce a new term) diets if the first two ISOs are correct. But this is not always the case.This makes comparison easier if you want to know the effect of the diets and for that matter the test ingredients on the fed species.

If I got you right you wanted to know the effect of different sources of proteins alongside different replacement levels, thus 10%, 20%, 30% and 40% in one experiment. This is a bit complicated especially if you have more than 2 test ingredients with 3 replicates for which you would require a number of experimental tanks. Your experimental design is likely to be one of a two-factorial design. 

With regards to Winfeed package, I experienced similar challenges the first time I used it. However, it was helpful at the end. You need to know the protein (P), lipid (L) and energy (E) contents of your ingredients (depending on the kind of diet you want to formulate). Make sure your feed store is updated whenever there are changes in the nutrient profile of the ingredients. You can then adjust the inclusions of the ingredients whiles keeping an eye on how a change in one ingredient afffects the PLE of the diet. Remember the package enables you to set limits (Min and Max) for both nutrient requirements and ingredient levels. It is good to start with lower values and increase them gradually until you reach your desired. Also make use of decimals. 

I hope this would be helpful. All the best!

Hi Collins,

Thanks for your mind. Is there any other ways to know the energy for the ingredients beside bomb calorimeter? 

Hi Mohd,

Yes, probably. This is done by multiplying the Protein, Fat and Carbohydrate content of the ingredients by a conversion factor. Maybe the attached FAO document can help you. However, the BC gives you the actual energy content.

All the best.

Book Food Energy – Methods of Analysis and Conversion Factors

Collins,

I can't retrieved the attached FAO doc. Can you email me the doc? [email protected]

Isonitrogenous diets = diets containing the same protein content

Isocaloric diets = diets containing the same energy content

I would presume that now you know the definitions of the two terms.  First of all, it is difficult to have isonitrogenous and isocaloric when dealing with plant protein source or anything with high fiber content.  So that most fish nutritionist test only low inclusion levels like 3, 6 or 9% of a plant protein source.  but if you are evaluating a protein source which contain high protein, it would be so easy to prepare the isos.  Also remember that the delineation between a protein supplement and a non-protein supplement (perhaps it supplements other things) is arbitrarily set at 20% CP.  This means that if the CP is about 15% (such as seaweed), you can only include at best about 6% of the diet.  But if you have a way to concentrate the protein from that protein source, then your preparation problem will be easier and your level of inclusion would be higher.

isocaloric diets are diets with the same caloric density while isonitrogenous diets are those with the same protein level.

I'm agree with Efosa.

One common mistake in diet studies is the failure to insure that dietary treatments have the same caloric density (isocaloric) or the same protein level (isonitrogenous) when they should.Thus, simply exchanging ingredients will change the energy level of the diet as well as the protein level and confound the experiment with an extra variable. Energy must be added to some of the diets to make them isocaloric.

The same principle can be applied to experiments that include diets with different protein sources as dietary treatments. In this case, care must be taken to make sure that the growth effects being measured are due to protein source rather than protein level. The diets are made isonitrogenous by varying the level of the protein sources according to the protein content of each

I totally agree with the ideas of Alireza,

I also agree with the explanation of Alireza chegeni.

Regards

SM Najim

Isocaloric diets have calories that are approximated to be equal whiles isonitrogenous are approximated to have equal protein content.

I am happy for all answers and i can use it to formulate for poultry diet.

I strongly agree with Augusto Serrano Jr.

Please can I establish that two diets are isocaloric based on their energy values? and what range of difference in the energy values can i use to establish this.

isocaloric and isonitrogenous diets are usually experimental diets with the same energy and protein levels for the different treatment groups of animals.