Effects of the level of dietary valine supply on amino acids and urea concentration in milk and blood plasma of lactating sows.
In order to determine the valine (Val) requirement, suckling sows with 10-12 piglets were supplied with feed mixtures, which contained various levels of Val derived by adding crystalline L-Val to the native diet (0.45% = native, 0.55, 0.65, 0.85, 1.05 and 1.45%) during a total of 72 lactations. Milk and blood plasma, taken after 3 weeks of lactation, was examined on the concentration of amino acids (total amino acids in milk, free amino acids in plasma) and urea by ion exchange chromatography or autoanalyzer, respectively. The contents of almost all amino acids in milk were significantly higher compared with the native diet, when Val was supplemented, reflecting increasing milk protein concentrations. Highest amino acid concentrations were observed with 0.85% dietary Val. Amino acid pattern in milk was not affected by the Val supply. In blood plasma the concentration of free Val rose with the dietary Val from 9 mg/l (0.45% dietary Val) to 132 mg/l (1.45% dietary Val). Several other amino acid contents were also higher when Val was added to the native diet, but there was no dose-response. Urea concentrations in milk and blood plasma were lowest with 0.65% and 0.85% dietary Val, respectively. Conclusively, for sows nursing litters with 10-12 piglets a dietary valine supply of 0.85% (0.75% apparent ileal digestible Val) can be recommended with a minimum requirement of 0.65% (0.55% apparent ileal digestible Val).
Division of Animal Nutrition, Technical University Munich, Freising-Weihenstephan, Germany. Roth-Maier@wzw.tum.de
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Roth-Maier
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Ott
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Paulicks
D000596:Amino Acids / Q000032:analysis / Q000097:blood*; D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D005260:Female; D007774:Lactation / Q000502:physiology*; D008892:Milk / Q000737:chemistry*; D010949:Plasma; D013552:Swine / Q000097:blood*; D014508:Urea / Q000032:analysis / Q000097:blood*; D014633:Valine / Q000494:pharmacology*
D000596:Amino Acids; D014508:Urea; D014633:Valine