Free amino acids in the plasma of poults used as an indicator of possible limiting amino acids in presently available protein sources.
Free amino acids in the plasma of poults were used to determine limiting amino acids in turkey starter diets that incorporated each of four protein sources (pea protein concentrate, dehulled soybean meal, herring fish meal, and poultry residue meal) in comparison with a control diet that contained fish meal and soybean meal. The control diet has been consistent in producing maximum growth with lower free amino acid levels in the blood plasma of poults in our laboratory. The diet that contained pea protein concentrate plus added methionine produced significantly lower plasma levels of methionine, arginine, proline, threonine, leucine, and taurine than the control values. The addition of threonine to the methionine supplemental pea protein concentrate significantly reduced the free isoleucine and leucine in the plasma. Soybean meal with methionine failed to produce a weight gain equal to the control diet, supplementing lysine improved growth rate, and threonine was the next limiting amino acid. The poults fed the herring fish meal basal diet with no amino acid supplementation produced a growth rate equivalent to the control birds. Free methionine was significantly lower, which indicated less available methionine in the fish meal. Supplementation of 26% poultry residue meal with methionine and lysine improved growth rate. Further addition of histidine or histidine and tyrosine resulted in no further improvement in growth rate. The free amino acids in the plasma would indicate that methionine, lysine, histidine, leucine, and isoleucine were limiting in the poultry residue meal studied.
D000596:Amino Acids / Q000032:analysis / Q000097:blood*; D000818:Animals; D004044:Dietary Proteins / Q000032:analysis; D008297:Male; D009753:Nutritive Value; D010940:Plant Proteins / Q000032:analysis; D014422:Turkeys / Q000097:blood* / Q000254:growth & development
D000596:Amino Acids; D004044:Dietary Proteins; D010940:Plant Proteins