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Effects of duodenal casein and glutamic acid infusion on small intestinal starch digestion and energy and nitrogen balance in cattle.

S. Acharya

Events

06-23-2020

Abstract:

182
Effects of duodenal casein and glutamic acid infusion on small intestinal starch digestion and energy and nitrogen balance in cattle.
S. Acharya*, E. A. Petzel, E. A. Bailey, D. W. Brake. Division of Animal Sciences, University of Missouri Columbia, MO.

Small intestinal starch digestion (SISD) is limited in cattle, but it can be improved by postruminal flow of casein or glutamic acid. The objective of this experiment was to evaluate effects of postruminal flow of casein or Glu on SISD and to quantify improvements in energy and nutrient balance. Twenty-two steers (BW = 179 � 4 kg) were duodenally infused with raw cornstarch (1.46 � 0.04 kg/d) and either 413 � 7.0 g casein (CAS)/d, 121 � 3.6 g Glu /d or water (CON). Measures of SISD and nutrient excretion were collected across 4 d after 42 d of infusion and measures of respiration via indirect calorimetry were collected across 2 d after —48 d of infusion. Ileal starch flow was least (P = 0.05) among calves provided CAS, but ileal starch flow was not different (P = 0.60) between Glu or CON. Correspondingly, SISD tended (P = 0.11) to be greatest among calves provided CAS, compared with Glu or CON. Casein increased (P < 0.01) ileal flow of ethanol-soluble starch compared with Glu and CON. Large intestinal starch digestion was similar (P = 0.39) across treatments. By design, N intake (P < 0.01) was greatest among cattle provided CAS, intermediate among calves provided Glu and least for CON. Nitrogen retention was greater (P < 0.01) in response to CAS compared with CON and Glu. Intake of GE from feed was similar (P = 0.75) across treatments, and GE from infusate was greatest for CAS, intermediate for Glu and least for CON. Variation in GE intake from feed resulted in no difference in overall GE intake (P = 0.49) across treatments. Similar to measures of SISD and N retention, CAS increased DE (P = 0.04) and ME (P = 0.02), compared with Glu and CON, which did not differ (P > 0.20). Postruminal infusions did not influence ruminal methane production (P = 0.90), but heat production tended to be greater (P = 0.06) among steers infused with CAS. Overall, amounts of energy retained by CAS tended (P = 0.12) to be nearly 34% greater than CON, but Glu had no impact on energy balance (P = 0.43). Improvement in SISD in response to CAS increased energy and N retained; however, Glu did not influence SISD and energy or N balance in cattle.

Keywords: starch digestion.