Journal of Animal Science, Vol 75, Issue 4 1119-1129, Copyright © 1997 by American Society of Animal Science

JOURNAL ARTICLE

The effect of abomasal infusion of casein and recombinant somatotropin hormone injection on nitrogen balance and amino acid fluxes in portal-drained viscera and net hepatic and total splanchnic blood in Holstein steers

I. Bruckental, G. B. Huntington, C. K. Baer and R. A. Erdman
Department of Animal Sciences, University of Maryland, College Park 20742, USA.

Six Holstein steers, 6 mo of age, with a BW range of 180 to 200 kg were used to determine effects of abomasal casein infusion and recombinant bovine somatotropin on amino acid absorption and metabolism in the gut and liver. Catheters were positioned in the hepatic vein, the hepatic portal vein, two mesenteric veins, and a mesenteric artery. Using the same basal diet, treatments consisted of 1) basal diet only (Control), 2) abomasal casein infusion of 300 g/d (Casein), and 3) abomasal casein infusion plus daily injection of 20 mg of bovine somatotropin (ST). All steers were fed the basal diet at a rate of 24 g/kg of BW on a DM basis, in 12 equal meals at 2-h intervals. Initially, Casein and ST treatments were in a balanced cross-over design, and then all steers received the Control treatment. Casein infusion tended to increase BW gain but did not affect BW gain per unit of N intake. The ST treatment increased weight gain (P < .01) and efficiency of dietary DM (P < .01) and N (P < .01) utilization by more than 40% and increased the percentage of absorbed N retained. Nonessential, essential, and total amino acid fluxes in portal-drained viscera (PDV) and their net removal by the liver were not affected by casein infusion. However, ST tended to reduce PDV flux of essential, nonessential, and total amino acids by approximately 30%, and their removal by the liver (P < .08). As a result, ST increased, compared with casein, release of essential (P < .06) and total (P < .10) amino acids from the total splanchnic pool (TSP) into peripheral blood. The ST treatment increased the availability of absorbed amino acids to peripheral tissues, but it did not affect the amino acid profile delivered from splanchnic tissues, especially that of essential amino acids.

This article has been cited by other articles:

				S. W. El-Kadi, K. R. McLeod, N. A. Elam, S. E. Kitts, C. C. Taylor, D. L. Harmon, B. J. Bequette, and E. S. Vanzant Nutrient net absorption across the portal-drained viscera of forage-fed beef steers: Quantitative assessment and application to a nutritional prediction model J Anim Sci, September 1, 2008; 86(9): 2277 - 2287. [Abstract] [Full Text] [PDF]

				A. V. Capuco, G. E. Dahl, D. L. Wood, U. Moallem, and R. E. Erdman Effect of Bovine Somatotropin and Rumen-Undegradable Protein on Mammary Growth of Prepubertal Dairy Heifers and Subsequent Milk Production J Dairy Sci, November 1, 2004; 87(11): 3762 - 3769. [Abstract] [Full Text] [PDF]

				U. Moallem, G. E. Dahl, E. K. Duffey, A. V. Capuco, D. L. Wood, K. R. McLeod, R. L. Baldwin VI, and R. A. Erdman Bovine Somatotropin and Rumen-Undegradable Protein Effects in Prepubertal Dairy Heifers: Effects on Body Composition and Organ and Tissue Weights J Dairy Sci, November 1, 2004; 87(11): 3869 - 3880. [Abstract] [Full Text] [PDF]

				U. Moallem, G. E. Dahl, E. K. Duffey, A. V. Capuco, and R. A. Erdman Bovine Somatotropin and Rumen-Undegradable Protein Effects on Skeletal Growth in Prepubertal Dairy Heifers J Dairy Sci, November 1, 2004; 87(11): 3881 - 3888. [Abstract] [Full Text] [PDF]

				L. Doepel, D. Pacheco, J. J. Kennelly, M. D. Hanigan, I. F. Lopez, and H. Lapierre Milk Protein Synthesis as a Function of Amino Acid Supply J Dairy Sci, May 1, 2004; 87(5): 1279 - 1297. [Abstract] [Full Text] [PDF]

				I. Savary-Auzeloux, L. Majdoub, N. Le Floc'h, and I. Ortigues-Marty Ryegrass-based diet and barley supplementation: Partition of nitrogenous nutrients among splanchnic tissues and hind limb in finishing lambs J Anim Sci, December 1, 2003; 81(12): 3160 - 3173. [Abstract] [Full Text] [PDF]

				J. A. Bush, D. G. Burrin, A. Suryawan, P. M. J. O'Connor, H. V. Nguyen, P. J. Reeds, N. C. Steele, J. B. Van Goudoever, and T. A. Davis Somatotropin-induced protein anabolism in hindquarters and portal-drained viscera of growing pigs Am J Physiol Endocrinol Metab, February 1, 2003; 284(2): E302 - E312. [Abstract] [Full Text] [PDF]

				J. P. Blouin, J. F. Bernier, C. K. Reynolds, G. E. Lobley, P. Dubreuil, and H. Lapierre Effect of Supply of Metabolizable Protein on Splanchnic Fluxes of Nutrients and Hormones in Lactating Dairy Cows J Dairy Sci, October 1, 2002; 85(10): 2618 - 2630. [Abstract] [Full Text] [PDF]