title: Effect of decreasing ideal protein levels on performance results and nitrogen efficiency of growing-finishing gilts.
abstract: This study examined the effect of decreasing ideal protein concentrations on performance and nutrient efficiency. The experimental diets contained 100%, 90%, 80% or 70% of the ideal dietary protein level (Diet 100%, 90%, 80% and 70%, respectively) estimated in previous experiments with pigs of the same genetic background. The four different treatments were divided among 16 pens of six pigs each. The average initial and final body weight were 20.8 +/- 1.1 and 107 +/- 3 kg, respectively. Three-phase feeding was applied (BW 20-40 kg, 40-70 kg and 70-110 kg). The dietary ileal digestible (ID) methionine + cystine, threonine, tryptophan, isoleucine, valine, and leucine contents expressed as percent of ID lysine were 63, 72, 22, 60, 68, and > 100%, respectively. The lysine to protein ratio was kept constant at 6.8%. Between 21 and 106 kg BW the best performance was achieved on Diet 90%. Diet 70% led to significantly worse results. Although lean meat percentage did not differ, protein content of the carcass was lower on Diet 70% than on Diets 90% and 100%. Decreased protein concentrations increased crude protein efficiency and consequently decreased nitrogen excretion most at the 80% level. If protein varies together with digestible amino acid content, it can be concluded that Diet 80% may be the best choice for the environment and for profitability. If protein content stays at a fixed level, Diet 90% may be the safest choice.
authors.affiliation: Institute for Agricultural and Fisheries Research (ILVO), Animal Sciences Unit, Melle, Belgium. sam.millet@ilvo.vlaanderen.be
authors.forename: Sam
authors.initials: S
authors.lastname: Millet
authors.forename: Marijke
authors.initials: M
authors.lastname: Aluwé
authors.forename: Marc
authors.initials: M
authors.lastname: De Paepe
authors.forename: Daniël L
authors.initials: DL
authors.lastname: De Brabander
authors.forename: Monique J
authors.initials: MJ
authors.lastname: Van Oeckel
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004032:Diet / Q000662:veterinary; D004044:Dietary Proteins / Q000494:pharmacology*; D005260:Female; D009584:Nitrogen / Q000378:metabolism*; D013552:Swine / Q000254:growth & development*; D015430:Weight Gain / Q000187:drug effects
chemical_list: D004044:Dietary Proteins; D009584:Nitrogen