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Key words:

Animal nutrition,

amino acids,

nitrogen excretion

Better knowledge of the response of pigs to the supply of limiting amino acids to optimize growth and to limit nitrogen excretion

To reduce nitrogen excretion, the utilization of dietary protein by the animal has to be improved. Piglets have a limited feed intake capacity and a strong potential for protein deposition.

The reduction of the protein content in the diet, accompanied by the supply of free amino acids such as lysine, threonine, methionine and tryptophan has resulted in an improved dietary amino acid profile and has increased the efficiency of nitrogen utilization while maintaining animal performance.

Despite this favorable context, a further reduction in dietary protein content is limited by the lack of knowledge about the requirements for the next-limiting amino acids.

The pig has the biological potential to efficiently use dietary amino acids

• We have identified the limiting factors for the further reduction of the dietary protein content for piglets and we provided estimates of the requirements for valine, isoleucine, leucine, and histidine, which will allow the formulation of diets with a very low protein content.
• We showed that it is technically possible to reduce nitrogen excretion by piglets by 20% by using diets with a very low protein content and supplemented with free amino acids.
• We also proposed that metabolic signals may be at the origin of the immediate reduction in feed intake when piglets consume a diet deficient in valine.

Combining precision protein with precision feeding

To exploit the biological potential of the animal while reducing nitrogen excretion, it is important that the amino acid profile of the diet is close to the requirement of the animal all along its productive life.

The benefits of formulating diets based on “precision protein” would be even greater if precision feeding techniques are used, where each individual within a population receives the diet it requires. Formulating diets with a very low protein content also reduces the utilization of imported protein sources.

For further information

• Gloaguen M., Le Floc'h N., Brossard L., Barea R., Primot Y., Corrent E., van Milgen J. (2011). Response of piglets to the valine content in diet in combination with the supply of other branched-chain amino acids. Animal 5 (11): 1734-1742. (DOI)
• Gloaguen M., Le Floc'h N., Corrent E., Primot Y., van Milgen J. (2012). Providing a diet deficient in valine but with excess leucine results in a rapid decrease in feed intake and modifies the postprandial plasma amino acid and α-keto acid concentrations in pigs. Journal of Animal Science 90 (9): 3135-3142. (DOI)
• Gloaguen M., Le Floc’h N., Corrent E., Primot Y., Val-Laillet D., Meunier-Salaün M.C., van Milgen J. (2013). Meal patterns in relation to the supply of branched-chain amino acids in pigs. Journal of Animal Science 91 (1): 292-297. (DOI)
• Gloaguen M., Le Floc'h N., Primot Y., Corrent E., van Milgen J. (2013). Response of piglets to the standardized ileal digestible isoleucine, histidine and leucine supply in cereal-soybean meal-based diets. Animal 7 (6): 901-908. (DOI)

Valorisation 

The results of this work have been presented at numerous scientific and technical meetings in France and abroad (Austria, Belgium, Denmark, Germany, Italy, Spain, and the Netherlands).

Partnership

This work has been carried out in partnership with Ajinomoto Eurolysine S.A.S. through a CIFRE doctoral scholarship).

Contacts

Jaap van Milgen (jaap.vanmilgen(at)rennes.inra.fr)
Nathalie Le Floc’h (nathalie.lefloch(at)rennes.inra.fr)