Non-protein nitrogen improves feed efficiency of growing pigs fed a diet deficient in non-essential amino acid nitrogen

Monday, July 21, 2014
Exhibit Hall AB (Kansas City Convention Center)
Wilfredo D Mansilla , University of Guelph, Guelph, ON, Canada
John K Htoo , Evonik Industries AG, Hanau-Wolfgang, Germany
Cornelis FM de Lange , University of Guelph, Guelph, ON, Canada
Abstract Text:

In pig diets the balance between essential amino acids (EAA) and total nitrogen (N) should be considered, especially when large amounts of crystalline EAA are supplemented and N levels are reduced.  When lowering dietary N, the dietary supply of non-essential amino acids (NEAA) is reduced and the need of N for endogenous synthesis of some NEAA may be increased, requiring N from either catabolism of excess EAA and NEAA or non-protein nitrogen (NPN).  The objective of the present study was to determine the effect of supplementing NPN, in the form of ammonium salts, in diets deficient in NEAA-N on performance of growing pigs.  In total, 48 gilts (initial BW of 15.2 ±1.3 kg) were randomly assigned to 4 diets: (1) positive control (PC; 13.39% CP), not deficient in EAA and NEAA-N, and all N was supplied from intact protein (casein and soybean meal) or crystalline EAA, (2) negative control (NC; 10.19% CP), supplying the same amount of potentially limiting EAA as PC, but deficient in NEAA-N, (3) NC with 3 g/kg added ammonium (Low NPN), and  (4) NC with 6 g/kg added ammonium (High NPN); the latter containing the same amount of digestible N as PC.  Pigs were grouped in 2 pigs per pen with 6 pens per treatment.  BW gain and feed intake were monitored weekly during 3 weeks, and blood samples were taken on days 14 and 21 to determine plasma urea concentration.  Week 1 yielded poor growth performance and was considered a week of adaptation.  During weeks 2 and 3, BW gain was not affected by NPN (P > 0.10); while feed intake tended to decrease with increasing dietary NPN (P = 0.06).  Gain:feed, improved linearly with supplementation of NPN in diets (P < 0.05; 0.45, 0.47 and 0.51 for NC, Low and high NPN during weeks 2-3).  Gain:feed for High NPN was similar to that for PC (P > 0.10: 0.51 and 0.52 for High NPN and PC; week 2-3).  Plasma urea concentration was low and not different between diets (P > 0.10).  Dietary supplementation with NPN, in the form of ammonium salts, can improve pig performance when pigs are fed diets deficient in NEAA-N.

Keywords: growth, nitrogen, pigs.