Concept and application of ideal protein for pigs

Abstract

Knowledge about the amino acid requirements and the response of pigs to the amino acid supply is essential in feed formulation. A deficient AA supply results in a reduction in performance while an oversupply is costly and leads to excessive nitrogen excretion with a potentially negative environmental impact. Amino acid requirements are determined to a large extent by the protein deposition in the body and, for lactating sows, by the protein exported in the milk. The concept of ideal protein was developed more than 50 years ago and refers to a protein with an amino acid profile that exactly meets the animal’s requirement so that all amino acids are equally limiting for performance. Because Lys typically is the first-limiting amino acid, the ideal amino acid profile is often expressed relative to Lys. Although the ideal protein profile is often assumed to be constant for a given production stage, (small) changes in the ideal protein profile can occur within a production stage. This can be caused by changes in the relative contribution of the different components of amino acid requirements during the productive life on the animal (e.g. changes in the relative contribution of growth and maintenance). Amino acids requirements can be determined experimentally using dose–response studies. The design of the study, the chosen response criterion, and the statistical model affect the requirement estimate. Although considerable experimental work has been carried out to determine the requirements for Lys, Met, Thr, and Trp in growing pigs (and to a lesser extent in sows), little is known about the requirements for the other essential amino acids. Experimental dose–response studies generally focus on the requirement and less on the overall response (i.e. what are the consequences of an amino acid deficiency?). This latter aspect is, to some extent, accounted for in modelling approaches that quantify the response of the animal to the amino acid supply in a dynamic way. The paper describes the origin of ideal protein and illustrates how fundamental concepts of amino acid nutrition have been integrated in practical modeling approaches for the nutrition of growing pigs and sows.

Impact of amino acid and CP restriction from 20 to 140 kg BW on performance and dynamics in empty body protein and lipid deposition of entire male, castrated and female pigs

“…The efficiency of dietary protein utilisation by the pig depends on the digestibility of the amino acids and the dietary amino acid profile itself in relation to the animal's requirements (Van Milgen and Dourmad, 2015). Some of the low CP diets had an unbalanced EAA pattern according to the Swiss feeding recommendations for pigs.…”

“…Their sources are protein and non-protein N which is either undigested and excreted via faeces or digested and voided through urine. The increasing concern about the environmental impact of pig production (Wood et al, 2013), together with limitations in availability and high costs of dietary protein sources (Wood et al, 2013;Van Milgen and Dourmad, 2015), make the reduction of the dietary protein content a priority objective in pig production. Dietary protein intake should, as far as possible, accurately cover the requirements for fully exploiting the genetic potential for growth without excessive intake.…”

Amino acid requirement of growing and finishing pigs

“…A deficient supply of AA will reduce the performance of pigs whereas an oversupply will increase the nitrogen excretion (Van Milgen and Dourmad, 2015). In the Netherlands, AA recommendations for pigs are published by the Centraal Veevoederbureau (CVB).…”

“…It is now common practice to express AA requirements on a standardized ileal digestible (SID) basis instead of on a AID basis (Van Milgen and Dourmad, 2015). Standardization means that the AID is corrected for basal endogenous losses, which are assumed to depend on dry matter intake (Van Milgen and Dourmad, 2015).…”

Branched chain amino acids in feeding pigs: Review

“…Pesquisas recentes (Gloaguen et al, 2014 demonstraram que a concentração da PB das rações está sendo reduzida por meio de formulações baseadas nas exigências dos AA essenciais, como os ACR, lisina e triptofano, bem como utilizando o conceito da PB (Van Milgen and Dourmad, 2015). Reduzindo a porcentagem de PB na dieta de leitões recém-desmamados e avaliando diferentes níveis de valina (Val) em relação à lisina (0,58; 0,62; 0,66; 0,70; 0,74 e 0,78%), Soumeh et al (2015) observaram uma resposta significativa na CA, CDR e GPD, assim como aumento na concentração plasmática de Val.…”