[Content of essential amino acids in prematurely weaned piglets after a qualitatively and quantitatively variable protein diet]

A total of 60 piglets of German Landrace weaned at the age of 2 weeks were fed ad libitum with isoenergetic diets of different proteins (casein + dried skim milk, soybean protein + dried skim milk, only soybean protein) and different protein levels in the diet (20, 27, 34, 40% in D.M.). After 4 weeks the piglets were homogenized and examined for their content of essential amino acids in the whole body mass by ion exchange chromatography. On the fresh and dried material the contents of Thr, Val, Ile, Leu, Lys and Ser increased both with higher supply of protein and milk instead of soybean protein in the diet. The contents of Phe and Arg were only insignificantly changed by protein quality. Referred to the concentration of Met and Cys there were found higher standard deviations and interactions between protein supply and quality. The content of essential amino acids also was influenced by the protein quality of the diet, when related to the whole body protein. On the other hand a significant effect of increasing protein supply only took place if soybean protein was the single protein ingredient of the diet. Related to Lys the contents of Thr and Cys nearly were constant, whereas the amino acid/lysine proportion in the case of Met, Ile and Arg changed considerably.

[Effect of graded high-energy-level protein supply on fattening performance and retention and utilization of feed energy, protein and amino acids in female fattening swine. 4. Nitrogen and amino acid content in carcasses and parts]

The slaughtering and cutting up of 7 (6) female pigs in each of 3 groups (live weight approximately 113 kg) fed on approximately 80, 100 and 120% protein (lysine) of the norm as well as the determination of nitrogen and amino acids in the individual parts of the body had--in comparison to 6 reference animals (live weight approximately 36 kg) treated in the same way at the beginning of the experiment--the following results: In the course of growth the quota (in % of the slaughter weight) of bacon, belly fat + intestinal fat tissue is more than doubled; the relative quotas of bones, skin + ears, bristles + claws, blood and entrails, however, decrease. The total meat quota is 54% and remains relatively equal independent of the live weight. The N-quotas (in % of the empty body-N) of muscle and fat tissue and of the skin increase in the course of fattening, those of bones, useable organs and offal decrease distinctly. At the end of fattening the muscle protein of the animals amounted to 59% of the empty body protein and to 87% of the carcass protein. The amino acid content (g/16 g N) hardly changes in the individual parts during growth; the percentage amino acid distribution follows the weight-and N-distribution. The lysine content of the edible parts of the carcass is 8.4 g/16 g N. The chosen grades in the protein (lysine) supply of the test animals did not result in any significant changes with regard to the qualitative parameters (protein and amino acid content of the valuable and less valuable parts of the body as well as their percentage distribution in the empty body). The quantitative parameters (live weight gain, protein (amino acid) retention per day) are diminished in approximately the same relation as the insufficiency of the alimentary supply; by excessive supply, however, they do not significantly increase. The results are compared with corresponding data from literature and discussed.