Deliverable D2.4 A database with traits related to variation in amino acid utilization in pigs

Objectives

Feed-a-gene aims to better adapt different components of monogastric livestock production systems to improve the overall efficiency and to reduce the environmental impact. This involves among others the development of new and alternative feed resources and feed technologies, the identification and selection of robust animals that are better adapted to fluctuating conditions and the development of feeding techniques that allow optimizing the potential of the feed and the animal. In the project, new traits related to feed efficiency have been developed to assess between animal variation in protein and amino acid (AA) requirements in growing pigs in response to different dietary and rearing regimes. The new traits can be used for modelling the response of animals to the nutrient supply and environmental conditions and for further developing precision feeding regimes in defined populations of growing pigs.
The database contains data on N-balance research with growing pigs aimed to establish the relationship between birth weight and genetic capacity of pigs to deposit protein, to the protein and amino acid utilization in pigs in dependence of the dietary supply of protein and amino acids (adequate and restricted). In addition, data on concentrations of nutrients, metabolites and hormones in blood with a potential relationship link to N-efficiency in pigs are included.

Rationale

The protein/nitrogen (N) and amino acid (AA)-digestibility and metabolic utilization of N and AA for deposition in the body of pigs depend on many factors including factors related to the animal (e.g. age, sex, breed, health status), to the diet composition (ingredient and, in particular, nutrient composition), feeding strategy (e.g. ad libitum or restricted) and to environmental and management factors such as climate in the housing facilities, stocking density of animals, and animal health management. For practical diet formulation, nutrient requirement values of pigs are generally presented as “average” recommendations/ standards based on results of a large number of requirement studies carried out with different designs and under different experimental conditions. This means that the match between dietary nutrient supply and nutrient requirements of a defined population of animals on a particular farm might be rather far from optimal. For that reason, it is important to get more information about the factors that could influence protein and amino acid requirements, which are currently not, or hardly, taken into account in diet formulation and to get information on new parameters linked to N-efficiency in pigs. For example, quantitative information about the effect of birth weight on N digestibility, N retention, and the metabolic utilization of protein and AA later in life is lacking. These effects could also influence the requirements for AA of pigs later in life. Considering factors such as birth weight can therefore contribute to explaining variation in growth responses and N-efficiency in populations of pigs. Differences in protein/N digestibility and N metabolism can be measured in N-balance studies. In addition, biomarkers in blood and/or urine might be very useful for in vivo estimation of amino acids requirements in animals.