Effects of starch and protein sources on starch disappearance in the gastrointestinal tract of Hanwoo (Korean native) steers

Abstract

Hanwoo (Korean native) steers (274.8 +/- 4.6 kg) with ruminal and duodenal cannulae were used in a 4 x 4 Latin square design experiment to examine the effects of dietary treatments on starch disappearance in the gastrointestinal tract. Dietary treatments consisted of concentrate that were based on ground corn with soybean meal (C-SBM), ground corn with corn gluten meal (C-CGM), ground barley with soybean meal (B-SBM) and ground barley with corn gluten meal (B-CGM). Although the intakes of starch and protein for steers fed experimental diets were different, it did not change ruminal pH and total volatile fatty acid concentrations. Average duodenal CP flow and quantity of CP apparently digested post-ruminally was higher (P = 0.001) for CGM-based diets than SBM-based diets. There were increases in quantity (P < 0.001) and percentage (P < 0.001) of corn starch digested post-ruminally compared to barley starch. Synchronized diets showed higher percentages (P = 0.03) of starch apparently digested post-ruminally than asynchronization. Hanwoo steers fed a corn-based diet with a large quantity of starch reaching the duodenum and fed C-CGM supplying great amounts of protein to the small intestine may have contributed to increased post-ruminal starch digestion.

Effects of Synchronization of Energy and Nitrogen Release in the Rumen on the Starch Disappearance in the Gastrointestinal Tract and Growth Performance of Hanwoo Steers

“…In agreement with our data, Khorasani et al (1994Khorasani et al ( , 2001 and Kim et al (2010) reported no differences in ruminal pH and total VFA concentrations between corn and barley but McCarthy et al (1989), Taniguchi et al (1991) and Khorasani et al (2001) reported greater total VFA concentrations in barley-based diets and it is due to the greater rate of degradation of nonstructural carbohydrates of barley than of corn. Molar proportions of individual VFA were not affected by the treatments, except for valerate, in the present experiment.…”

“…Molar proportion of valerate was significantly greater (p<0.05) from 4 h to 6 h for the barley-based diets than for corn-based diets in the present experiment, in agreement with Overton et al (1995). Comparing with the previous experiment (Kim et al, 2010), there was a difference in concentrate DM intake (1.7 vs. 1.2% of BW). This contributed to the differences in total VFA (128 vs. 100 mM) between experiments.…”

“…And also, there were no differences statistically in the quantity and percentage of OM apparently digested postruminally between the diets. In the previous study with same diets, however, Kim et al (2010) showed a significantly higher apparent ruminal OM disappearance (quantity and percentage of intake) and a significantly lower apparent postruminal OM disappearance (quantity and percentage of intake) for steers fed B-SBM diet than for steers fed C-CGM diet.…”

“…In the previous study, Kim et al (2010) reported significant difference in apparent ruminal CP outflows (155 vs. 117% of CP intake) and ruminal CP disappearance (quantity and percentage of intake) between C-CGM and B-SBM diets. Fecal flow of CP tended to be lower (p=0.1) and percentage of CP apparently digested postruminally tended to be higher (p=0.09) in steers fed B-SBM than for C-CGM in the present study.…”

“…In the previous report, Kim et al (2010) demonstrated that synchronizing the degradability of starch and protein sources (diets by mixing barley with soybean meal or corn with corn gluten meal) in the rumen showed higher percentages of starch apparently digested post-ruminally than asynchronization (diets by mixing barley with corn gluten meal or corn with soybean meal). However, data demonstrating the degree of synchrony of energy and nitrogen release in the rumen on digestion of starch in the small intestine and improvements in growth performance of animal are limited.…”