Effect Of Recombinant Porcine Somatotropin Rpst And Dietary Crude Protein Concentration On Lipid Metabolism And Carcass Composition Of Finishing Pigs PDF Download

A total of eight experiments utilizing 572 finishing pigs were conducted to evaluate the effect of reducing dietary protein level and adding amino acids on pig performance, carcass characteristics, and N excretion. The valine requirement of early-finishing (50 to 80 kg) barrows and the effect of adding isoleucine (Ile) and valine (Val) in amino acids fortified low-protein diets on finishing pig performance were also evaluated. In the first experiment (Exp. 1 of Chapter II), it was determined that the CP level in the diet for early-finishing (50 to 80 kg) gilts can be reduced up to four percentage units by adding Lys, Thr, Trp, and Met, with no detrimental effect on pig performance or carcass characteristics. The second study (Exp. 2 of Chapter II) indicates that Ile and/or Val may be limiting in a four-percentage-unit-protein-reduced diet for late-finishing (80 to 120 kg) gilts. The third experiment (Exp. 1 of Chapter III) indicates that the true digestible Lys requirement of early-finishing PIC barrows is not higher than 0.70%. In the fourth experiment (Exp. 2 of Chapter III), it was demonstrated that dietary protein level for early-finishing PIC barrows can be reduced up to five percentage units by adding Lys, Thr, Trp, Met, and Ile, with no detrimental effect on pig performance or carcass characteristics. Valine was not limiting in a 10.49% CP diet for early-finishing PIC barrows with ADFI of 3.1 kg/d, and the true digestible Val requirement of early-finishing PIC barrows gaining 1.0 kg/d, was not greater than 11.4 g/d. In the fifth experiment (Exp. 3 of Chapter III), we found that decreasing dietary protein level by 4.81 percentage units and adding amino acids to the diet reduced N excretion of early-finishing barrows by 40.6%. In the sixth experiment (Exp. 4 of Chapter III), it was determined that the dietary protein level for early-finishing barrows can be reduced up to four percentage units by adding Lys, Thr, Trp, and Met, with no detrimental effects on pig performance or carcass characteristics, and reducing dietary protein level by four percentage units can reduce N excretion by 38.4%. In the seventh experiment (Exp. 1 of Chapter IV), it was determined that late-finishing barrows fed an amino acid (Lys, Thr, Trp, Met, Ile, and Val) fortified corn diet (7.92% CP) have similar performance and carcass characteristics as pigs fed a corn-soybean meal control 12.50% CP diet. Deleting Ile or Val in an amino acids fortified corn diet may decrease pig performance. In the eighth experiment (Exp. 2 of Chapter IV), it was determined that late-finishing gilts fed an amino acid (Lys, Thr, Trp, Met, Ile, and Val) fortified corn diet (9.55% CP) have similar performance and carcass characteristics as pigs fed a corn-soybean meal control 15.17% CP diet. Decreasing dietary CP level from 15.17 to 9.55% decreases N excretion of late-finishing pigs by 48.28%. Deleting Ile or Val in an amino acid fortified corn diet may decrease pig performance. In summary, finishing pigs fed a low protein diet properly fortified with crystalline amino acids can have similar performance and carcass characteristics as pig fed typical protein level corn-soybean meal control diets, and N excretion will be greatly reduced.