UBC Theses and Dissertations
Amino acid supplementation of Peace River barley for growing-finishing pigs Chung, An Sik
The work reported in this thesis comprised two sections, each of which compared six rations in pigs in the body weight range 16-85 kg. All rations were based on barley. A supplement of L-lysine HC1 was added to provide a total lysine content of 0.90% and 0.75%, with the latter level also tested with 0.05% added L-threonine, alone or with 0.10% DL-methionine or 0.10% DL-methionine plus 0.10% L-isoleucine. A control ration consisted essentially of barley and soybean meal to provide 0.75% total lysine. These rations were used for growth and nitrogen balance experiments. The supplementation of barley with 0.50% L-lysine HC1 (0.75% total lysine) tended to improve nitrogen utilization more than a supplemental level of 0.69% L-lysine HC1 (0.90% total lysine). The biological value of the ration containing the lower level of lysine was significantly higher than that of the ration containing the higher level of lysine, which was reflected in a trend indicating that pigs fed the lower level of lysine were leaner and had larger eye muscle areas than those fed the higher level of lysine. Adding 0.05% L-threonine to the lower level of lysine improved growth performance but not carcass quality. The addition of L-lysine and L-threonine to the barley tended to improve nitrogen balance above that obtained by the addition of L-lysine alone. The further addition of 0.10% DL-methionine with or without 0.10% L-isoleucine did not improve growth performance but gave a further slight non-significant improvement in nitrogen metabolism measurements. Therefore, both the feeding experiment and nitrogen balance experiment indicated that threonine was the second limiting amino acid after lysine. Supplementation of barley with amino acids regardless of levels or combinations, gave significantly poorer daily gain, feed efficiency and carcass quality results but significantly higher biological value figures than the barley-soybean control ration. Thus, it would appear that the amino acid-supplemented rations still were deficient in some way, although the biological value data would tend to contradict the suggestion that this is associated with an amino acid imbalance.