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Fractional protein synthesis rates (FSR) are widely measured by the flooding dose technique via either an i.g. or an i.v. route. This study was conducted to compare differences in tracer incorporation and FSR in organs and tissues of fed piglets. The piglets were surgically implanted with catheters and randomly assigned to receive a flooding dose of Phe (1.5 mmol/kg body weight, 40 percent molar enrichment with [(2)H(5)]Phe) in saline administered via an i.p. or an i.v. route. [(2)H(5)]Phe free-pool enrichment in plasma increased logarithmically (P < 0.05) from 0 to 25% in the i.p. group, whereas it rose to a peak level within 3 min of the tracer injection and then decreased linearly (P < 0.05) in the i.v. group. Intracellular free-pool tracer enrichments in organs and tissues were within the range of the values measured for the plasma-free pool (25-27%), reaching the flooding status. Administration of the tracer via the i.p. and i.v. routes induced a logarithmical pattern (P < 0.05) of a surge in plasma cortisol concentrations within 30 min. Measurements of FSR in plasma, cardiac muscle, and skeletal muscles were lower (P < 0.05) in the i.p. than in the i.v. group due to the adverse effect of cortisol surge being more dramatic (P < 0.05) in the i.p. than in the i.v. group at 30 min of the post-tracer administration. We conclude that FSR may be measured by the flooding dose through an i.p. or an i.v. route and the i.p. route may underestimate FSR by the flooding dose for plasma, cardiac muscle, and skeletal muscles. This concern may be addressed by a fast regimen of sampling to be completed within 12-20 min after an i.p. route of tracer injection. [ABSTRACT FROM AUTHOR]

The article presents an abstract of the research paper "Maximum dietary content of corn distillers dried grains with solubles for laying hens: Nitrogen balance and egg production," by S. Roberts and colleagues.

The article presents an abstract of the research paper "Evaluation of a fine-limestone, low-energy molt program," by E. Donahue and colleagues.

An abstract of the article "Dietary corn distillers dried, grains with solubles does not affect generic E. coli numbers in the laying hen ceca," by S. Roberts and colleagues is presented.

An abstract of the article "Effects of supplemental lysine sources on egg-production and economic parameters for laying hens," by S. Roberts and colleagues is presented.

Our objectives were to examine the effect of an i.p. injection of a flooding dose of l-phenylalanine (Phe) containing l-[ring-(2)H(5)]Phe on time courses of physiologic responses, the tracer Phe enrichments, and fractional protein synthesis rates (FSR) in plasma, visceral organs, and muscles. In a randomized complete block design, 5 blocks of 5 littermate piglets were weaned at 16 d of age and injected i.p. with a flooding dose of l-Phe (1.5 mmol/kg body weight) on d 8 postweaning under fed conditions. Tissues were collected at 15, 30, 45, 60, and 75 min postinjection. Plasma glucose concentration increased (cubic effect, P < 0.05) from 4.8 preinjection to 5.8 mmol/L 15 min postinjection and returned to preinjection levels thereafter. Plasma insulin concentration did not change (P > 0.05) over time. Plasma Phe concentration increased logarithmically (P < 0.05) from 85 to 711 micromol/L and reached 95% of the maximum concentration 48 min postinjection, but no changes (P > 0.05) in tissue contents of other free amino acids were observed. The Phe free pools in plasma, visceral organs, and muscles were evenly enriched (32.3 +/- 1.4 mol%) with l-[(2)H(5)]Phe 15 min after the i.p. injection. The FSR in visceral organs did not change (P > 0.05), whereas plasma and muscle protein FSR decreased (P < 0.05) over time. We conclude that the i.p. injected tracer Phe rapidly distributed into plasma and intra- and extracellular spaces, and was effective for measuring FSR in visceral organs, but not in plasma and muscles of pigs.