[Methodical investigations on evaluation of lysine utilization in pigs after extreme changes of protein quantity and quality].
Aim of investigations was to measure lysine utilisation under dietary conditions which could have negative effects on well known relation between limiting amino acid and level of N-utilisation. Incorrect conclusions about level of lysine availability (efficiency) could be drawn under such conditions. Therefore N-balance trials were done with 32 female pigs (35-45 LW, fitted with urine bladder catheters), based on semisynthetic diets (wheatgluten / cornstarch) supplemented with glutamic acid as additional nitrogen source. Lysine concentration in the protein was further reduced by this way near to N-balance +/- 0. Data calculation followed a further developed N-utilisation model from Gebhardt (1966). Experimental conditions resulted in disturbed relationships between lysine concentration and protein utilisation and led to the conclusion, that N-balance trials related to estimation of amino acid efficiency in feed proteins resp. to amino acid requirements should be realised under conditions of > 500 mg / LWkg0.67 daily N-balance connected with > 2000 mg/LWkg0.67 daily N-intake.
Liebert
F
F
Universität Leipzig, Germany.
D000821:Animal Feed; D000818:Animals; D004044:Dietary Proteins; D005260:Female; D005527:Food, Fortified; D018698:Glutamic Acid / Q000378:metabolism; D005983:Glutens; D008239:Lysine / Q000378:metabolism*; D008954:Models, Biological; D009584:Nitrogen / Q000378:metabolism; D013213:Starch; D013552:Swine / Q000378:metabolism*; D014908:Triticum
D004044:Dietary Proteins; D018698:Glutamic Acid; D005983:Glutens; D013213:Starch; D008239:Lysine; D009584:Nitrogen