Lysine requirement of the lactating sow determined by using plasma urea nitrogen as a rapid response criterion.
The dietary lysine requirement of adult sows nursing 10 pigs was estimated by using plasma urea nitrogen (PUN) concentration as a rapid response criterion. A preliminary experiment indicated that a 3-d feeding time is required to re-equilibrate PUN concentrations after a change in the dietary concentration of lysine. In the main experiment, 12 sows (BW = 219 +/- 5 kg; parity = 4.5 +/- .3; ultrasound backfat = 21.3 +/- .9 mm) were used in two 6 x 6 Latin squares. Treatments consisted of dietary lysine intakes (30.2, 36.9, 43.6, 50.3, 57.0, and 63.7 g/d) that were assigned to six 4-d periods and to six sows in each square. Diets provided adequate levels of all nutrients other than lysine. The treatment periods started on d 5 of lactation and ended on d 29. Plasma urea N concentrations were determined on the 3rd and 4th d of each of the six 4-d treatment periods. Plasma urea N concentrations decreased quadratically (P < .02) with, increasing dietary lysine intakes. A two-slope, broken-line regression model was used to estimate the dietary lysine intake that minimizes PUN concentrations. The results indicated that adult sows nursing 10-pig litters with an average growth of 2.22 kg/d required 55.3 g/d of dietary total lysine to minimize PUN concentrations and, therefore, presumably to minimize body protein mobilization.
Coma
J
J
Department of Animal Science, Iowa State University, Ames 50011, USA.
Zimmerman
D R
DR
Carrion
D
D
D000818:Animals; D001806:Blood Urea Nitrogen; D004032:Diet / Q000662:veterinary*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007774:Lactation / Q000502:physiology*; D016014:Linear Models; D008239:Lysine / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology*; D009751:Nutritional Requirements; D011897:Random Allocation; D013552:Swine / Q000097:blood / Q000502:physiology*
D008239:Lysine