Valine requirement of nursery pigs

Six experiments were conducted to determine the true digestible valine requ irement of 5- to 20-kg pigs. In Exp. 1, a valine-deficient diet for 5- to 1 0-kg pigs was developed and validated in terms of growth performance in res ponse to supplemental L-valine. A different basal diet was validated for 10 - to 20-kg pigs in Exp. 2. Both diets were demonstrated to be deficient in valine and to support performance equivalent to typical nursery diets when fortified with L-valine. In Exp. 3, true ileal digestibility of valine in t he two basal diets was determined in eight pigs fitted with a simple T-cann ula at the terminal ileum. Another four pigs received an enzymatically hydr olyzed casein-based diet to determine endogenous contributions to collected ileal digesta. The two diets were found to have true valine digestibilitie s of 82% (5- to 10-kg pigs) and 86% (10- to 20-kg pigs). In Exp. 4, 80 wean ed pigs (5.8 kg) were offered the basal diet fortified with five incrementa l doses (0.08%) of L-valine. Weight gain increased quadratically (P < 0.05) with increasing levels of valine. Broken-line analysis revealed a true dig estible valine requirement of 0.86 +/- 0.03%. In Exp. 5, the true digestibl e valine requirement of 10- to 20-kg pigs was estimated with 120 pigs (10.9 kg) using the second basal diet fortified with six incremental doses (0.05 %) of L-valine. The data suggested a digestible valine requirement level of about 0.775%, which was reevaluated in Exp. 6, wherein pigs did not respon d to levels of digestible valine higher than 0.775%. In conclusion, require ment estimates were 2.50 and 2.22 g of true digestible valine per megacalor ie of ME for 5- to 10- and 10- to 20-kg pigs, respectively. These empirical estimates are in close agreement with recent estimates of the National Res earch Council Subcommittee on Swine Nutrition of 2.48 and 2.11 g of true di gestible valine per megacalorie of ME, respectively.