19 Assessment of Nitrogen Intake, Excretion and Deposition in lipopolysaccharide-Challenged Pigs

This study was conducted to assess the effect of E. Coli lipopolyssacharide challenge (IC) on Nitrogen Balance (NB) in growing pigs (19 kg). Three NB trials were performed in a complete RBD, with six nitrogen levels (NL), two sanitary status (control and IC) and two individual replicates per treatment (6 x 2 x 6). Pigs were intramuscular injected with 30 and 34 μg LPS/kg for two consecutive days. Dietary NL ranged from 1.06 to 4.48 % (dry matter), with lysine being limiting in all diets. NB trials lasted 11 days in which feces and urine were collected at the last four days to determine N intake (NI), N excretion (NEX) and N deposition (ND). Data were analyzed as two-way ANOVA and polynomial contrasts were used. Body weight were unaffected by the factors under study (P >0,05). LPS-challenged pigs had a lower (P< 0,05) feed intake compared with control group (372,98 vs. 417,82). Interaction between NL and IC were observed (P< 0,05) for NI, NEX and ND. NL linearly increased NI, NEX and ND, with different equations for both groups (P< 0,05): ND = 127,86 + 246,95 NL in control group whereas ND = 150,66 + 155,4 in LPS group. LPS-challenged pigs fed the three highest NL exhibited a decrease in NI compared with control group (P< 0,05). From NL2 to NL6, ND was also impaired in LPS-challenged pigs compared with control. Nitrogen excretion was higher in LPS-challenged pigs fed the two highest NL compared with pigs from control group (P< 0,05). In conclusion, LPS challenge impairs nitrogen retention in growing pigs by 37%. These outcomes can be used further for modelling procedures to estimate lysine requirements of pigs in different sanitary status.