Know more

A meal closer to the animal needs

In order to improve protein efficiency and nitrogen utilization by monogastric animals, the amino acid profile of the diet has to be close to the requirement of the animal all along its productive life. This amino acid requirement can be estimated by the factorial approach, which is based on:

• A constant amino acid composition in the retained body protein.
• The maximal efficiency of the amino acid utilization for growth.
• The amino acid requirement for maintenance.

Consistency of the amino acid composition is called into question

It is often assumed that the amino acid composition of retained protein is constant, but this assumption has been questioned because different tissues are composed of different proteins and the amino acid composition of body protein may be affected by the diet.
We recently showed in piglets that tissues respond differentially to a severely-deficient TSAA supply. However, the response to a prolonged and moderately deficient total sulfur amino acid supply on growth, body composition, and its impact on meat quality is not known, being the main objective of our studies.

Impact of a sulfur amino acid deficient supply

A prolonged and moderately-deficient TSAA supply in pigs and broiler chickens affected the amino acid composition in the longissimus dorsi and rhomboidus muscles, liver, proximal and distal jejunum, ileum and skin, and glycogen stores and the redness value (a*) of muscles, together with a reduction of performance and muscle weight. We propose that monogastric animals have different mechanisms to cope with a prolonged amino acid deficiency as tissues responded differently in terms of weight, tissue protein, lipid, and amino acid contents with a slight impact on meat quality. Muscle responded much more to a TSAA deficiency than did other tissues, such as the intestines. The observed changes in the amino acid composition of tissues and whole body protein question the use of a constant amino acid profile of retained protein in monogastric animals.

Physiology and metabolism of tissues, course to proteomics?

Our studies show that assuming a constant amino acid profile to assess the amino acid requirement by the factorial approach may not be appropriate. It is important to clarify how and why tissues respond differently to the deficient amino acid supply in terms of physiology and metabolism. We hypothesize that the change in amino acid composition of tissue protein by a total sulfur amino acid deficiency may be the consequence of changing proportions of different types of proteins. Moreover, changes in the equilibrium between protein synthesis and protein degradation of tissues may occur during a total sulfur amino acid deficiency. Therefore, further studies involving proteomics and protein turnover markers may help us to better understand the underlying mechanisms of how the animal responds to a deficient AA supply.

These studies were partially funded by the private company Adisseo and exhibited in numerous scientific and technical presentations in France, Turkey, Brazil and Spain. [Lien]

For further information

Conde-Aguilera J.A., R. Barea, N. Le Floc’h, L. Lefaucheur, J. van Milgen. 2010. A sulfur amino acid deficiency changes the amino acid composition of body protein in piglets. Animal 4 (8): 1349-1358. (DOI)
Conde-Aguilera J.A., C. Cobo-Ortega, S. Tesseraud, M. Lessire, Y. Mercier, J. van Milgen. 2013. Changes in body composition in broilers by a sulfur amino acid deficiency during growth. Poultry Sci. 92: 1266-1275. (DOI)
Conde-Aguilera J.A., C. Cobo-Ortega, S. Tesseraud, Y. Mercier, J. van Milgen. 2014. The amino acid composition of tissue protein is affected by the total sulfur amino acid supply in growing pigs. Animal 8 (3). (DOI)

Contact

Alberto Conde-Aguilera, Feeding and Nutrition research team (alberto.conde[at]rennes.inra.fr)