Use of plasma urea nitrogen as a rapid response criterion to estimate the lysine requirements of growing and lactating pigs

Abstract

Introduction Materials and Methods Results and Discussion Relationship of plasma urea N with lean tissue growth Variation in the plasma urea N response to dietary lysine Implications Literature Cited CHAPTER 5. INTERACTIVE EFFECTS OF FEED INTAKE AND STAGE OF GROWTH ON THE LYSINE REQUIREMENT OF PIGS Abstract Introduction Materials and Methods Results and Discussion Implications Literature Cited CHAPTER 6. LYSINE REQUIREMENT OF THE LACTATING SOW DETERMINED BY USING PLASMA UREA NITROGEN AS A RAPID RESPONSE CRITERION Abstract Introduction Materials and Methods Results and Discussion Preliminary experiment Main experiment Implications Literature Cited 126 CHAPTER 7. GENERAL SUMMARY 136 ACKNOWLEDGMENTS 139 APPENDIX. EQUATIONS TO ESTIMATE BODY COMPOSITION 140 accurately estimate the dietary lysine required to maximize total N utilization in pigs at a specific BW. In addition, the two-slope broken-line regression model had the highest R^ and lowest MSE when compared with three other models as means for estimating lysine requirement from PUN concentrations.

Effect of heat processing on nutrient digestibility in pea and supplementing amylase and xylanase to raw, extruded or micronized pea-based diets on performance of early-weaned pigs

“…The PUN is often used to determine efficiency of nitrogen utilization or body protein break down. A reduction in PUN concentration is an indication of reduced urea synthesis, hence more efficient use of AA for body growth (Coma et al 1995). However, it is important to note that this cannot be determined conclusively from the current study and that the higher CP content in the SBM-based diet might have also contributed to the higher PUN observed.…”

Optimum ratio of standardized ileal digestible tryptophan to lysine for piglets

“…Growth performance compared with PUN was shown to produce lower estimates of Lys requirement, which was attributed to the fact that AA requirement for maximum protein accretion, which is reflected by PUN, is higher than the requirement for maximum growth (Coma et al, 1995). However, this was not the case in the current study, implying that growth performance and PUN can produce similar estimates of SID Lys requirement by pigs.…”

“…This is because an increase in AA utilization by pigs due to an increase in dietary level of the first limiting AA results in a decrease in PUN concentration (Coma et al, 1995). Thus, PUN can be used to accurately determine the Lys requirement in pigs (Coma et al, 1995).…”

Performance and carcass characteristics of growing pigs and broilers fed diets containing micronised barley, ground barley, wheat and maize

“…PUN is often used to determine the efficiency of nitrogen utilisation. A reduction in PUN concentration reflects a decrease in urea synthesis and therefore more efficient utilisation of amino acids 19. Pigs fed MDB‐based diets had numerically lower PUN concentrations than those fed the 100% wheat‐based diet, but the reduction was significant ( P < 0.05) only for the 100% MDB‐based diet…”