caa a22 4500 386320101 CHVBK 20180307111623.0 cr unu---uuuuu 161130e198806 xx s 000 0 eng 10.1017/S000335610001905X doi S000335610001905X pii (NATIONALLICENCE)cambridge-10.1017/S000335610001905X Utilization of dl- and l-tryptophan in young pigs [Elektronische Daten] Two trials involving young pigs (total numbers 288 and 400, respectively) were performed to compare the biological activity of Dl- and L-tryptophan under restricted (trial 1) and ad libitum (trial 2) feeding conditions. In trial 1, three additions of Dl-tryptophan (0·3, 0·6 and 0·9 g/kg) and two additions of L-tryptophan (0·3 and 0·6 g/kg) to a basal diet containing 0·9 g natural tryptophan per kg were tested. In trial 2, the treatments were additions of 0·4, 0·8 and 1·2 g Dl- or L-tryptophan per kg to a basal diet having 1·3 g natural tryptophan per kg. Both trials were of 6 weeks duration. In trial 1, almost equal performance was achieved with both tryptophan sources at a dietary level of 0·3 g/kg, whereas at a level of 0·6 g/kg, Dl-tryptophan produced slightly better performance in weight gain, food intake and food conversion efficiency than did L-tryptophan. In trial 2, the supplemental level of 0·4 g L-tryptophan per kg produced weight gain and food intake results which were significantly superior to those of Dl-tryptophan. However, at supplemental levels of 0·8 and 1·2 g/kg, diets with Dl-tryptophan produced somewhat better performance than did L-tryptophan. Based on the results of trial 2, it was estimated that the pig's need for total tryptophan over the weight range of 10 to 35 kg is at least 2·3 g/kg in a diet having 10·3 MJ net energy per kg. Copyright © British Society of Animal Science 1988 Schutte J. B. TNO Institute of Animal Nutrition and Physiology, PO Box 15, 6700 AA Wageningen, The Netherlands van Weerden E. J. TNO Institute of Animal Nutrition and Physiology, PO Box 15, 6700 AA Wageningen, The Netherlands Koch F. Degussa AG, Industrial and Fine Chemicals Division, D-6450 Hanau, Federal Republic of Germany Animal Production Cambridge University Press 46/3(1988-06), 447-452 0003-3561 46:3<447 1988 46 ASC https://doi.org/10.1017/S000335610001905X text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S000335610001905X text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Schutte J. B. TNO Institute of Animal Nutrition and Physiology, PO Box 15, 6700 AA Wageningen, The Netherlands NATIONALLICENCE 700 1- van Weerden E. J. TNO Institute of Animal Nutrition and Physiology, PO Box 15, 6700 AA Wageningen, The Netherlands NATIONALLICENCE 700 1- Koch F. Degussa AG, Industrial and Fine Chemicals Division, D-6450 Hanau, Federal Republic of Germany NATIONALLICENCE 773 0- Animal Production Cambridge University Press 46/3(1988-06), 447-452 0003-3561 46:3<447 1988 46 ASC CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge