Effects of carbohydrates from citrus pulp and hominy feed on microbial fermentation in continuous culture.
Eight dual-flow continuous-culture fermenters were used to evaluate the effect of neutral detergent-soluble carbohydrates (NDSC) on fermentation by ruminal microorganisms. Citrus pulp and hominy feed were added to a basal diet as sources of NDSC, with citrus pulp providing neutral detergent-soluble fiber (NDSF) in the form of pectic substances and with hominy feed in the form of starch. The basal diet contained 26.7% corn silage, 6.0% alfalfa hay and 3.8% cottonseed hulls on a DM basis. The dried citrus pulp diet contained on a DM basis 17.2% CP, 34.7% NDF, 33.7% NDSC, and 14.4% NDSF, whereas the hominy feed diet contained 17.9% CP, 33.2% NDF, 35.9% NDSC, and 8.8% NDSF. Organic matter, DM, and NDF and ADF digestion were not affected by source of carbohydrate. Ammonia N concentration was greater (P < 0.05) for the hominy feed diet (14.2 mg/100 mL) than for the dried citrus pulp diet (9.3 mg/100 mL). Total N, nonammonia N, microbial N, and dietary N flows were not affected by treatments; however, the efficiency of microbial protein synthesis was greater (P = 0.055) for the dried citrus pulp diet than for the hominy feed diet (30.6 vs 27.8 g of bacterial N/kg of OM truly digested). Results from this experiment indicate that NDSF from citrus pulp can provide similar sources of energy compared with starch from hominy feed to support ruminal microbial growth.
Ariza
P
P
Department of Animal Science, University of Minnesota, St. Paul 55108, USA.
Bach
A
A
Stern
M D
MD
Hall
M B
MB
D000821:Animal Feed; D000818:Animals; D001419:Bacteria / Q000378:metabolism*; D002417:Cattle / Q000378:metabolism*; D002478:Cells, Cultured; D002957:Citrus / Q000737:chemistry*; D003902:Detergents; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D004043:Dietary Fiber / Q000378:metabolism; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005285:Fermentation; D009584:Nitrogen / Q000378:metabolism; D012417:Rumen / Q000378:metabolism* / Q000382:microbiology; D013213:Starch / Q000008:administration & dosage / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry*
D003902:Detergents; D004040:Dietary Carbohydrates; D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D013213:Starch; D009584:Nitrogen