Rumen Lipopolysaccharide and Inflammation During Grain Adaptation and Subacute Ruminal Acidosis in Steers

• Published in: Journal of dairy science Vol. 89; no. 11; pp. 4404 - 4413
• Main Authors: Gozho, G.N., Krause, D.O., Plaizier, J.C.
• Format: Journal Article
• Language: English
• Published: Savoy, IL Elsevier Inc 01.11.2006; American Dairy Science Association; Am Dairy Sci Assoc
• Subjects: Acidosis - diagnosis; Acidosis - physiopathology; Acidosis - veterinary; Adaptation, Physiological; Animal Feed - analysis; Animal productions; Animals; Biological and medical sciences; Cattle; Cattle Diseases - diagnosis; Cattle Diseases - physiopathology; cattle feeding; Cereal and baking product industries; Diet - veterinary; Eating - physiology; Enterobacteriaceae - isolation & purification; feed barley; feed concentrates; Food industries; Fundamental and applied biological sciences. Psychology; haptoglobin; Haptoglobins - analysis; Hordeum - metabolism; Hordeum vulgare; Hydrogen-Ion Concentration; inflammation; Jersey; lipopolysaccharide; lipopolysaccharides; Lipopolysaccharides - analysis; Male; pelleted feeds; Rumen - chemistry; ruminal acidosis; Serum Amyloid A Protein - analysis; serum amyloid-A; steers; subacute ruminal acidosis; Terrestrial animal productions; Time Factors; Triticum - metabolism; Triticum aestivum; Vertebrates; wheat; subacute ruminal acidosis; lipopolysaccharide; haptoglobin; serum amyloid-A; Bovine; Digestive system; Ox; Rumen; Inflammation; Vertebrata; Meat animals; Mammalia; Haptoglobin; Dairy industry; Lipopolysaccharide; Cereal; Serum; Amyloid; Artiodactyla; Acidosis; Ungulata; Adaptation
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(06)72487-0

Three rumen-fistulated Jersey steers were gradually adapted to a wheat–barley concentrate over a 4-wk period. Adaptation steps consisted of four 1-wk periods during which steers were fed diets with forage-to-concentrate (F:C) ratios of 100:0, 79:21, 59:41, and 39:61. The forage consisted of chopped hay (CH), and the concentrate consisted of pelleted concentrate containing 50% ground wheat and 50% ground barley. Steers were fed the all-forage diet ad libitum during wk 1. Feed offered in wk 2 to 4 was kept constant at the ad libitum intake during wk 1. On 2 d that were set 3 d apart during wk 5, subacute ruminal acidosis (SARA) was induced in the steers by feeding a diet with an F:C ratio of 24:76 by offering them 0.9kg of CH at 0900h followed by 2 meals of 3.0kg each of wheat–barley pellets (WBP) at 1100h and 1300h and 0.9kg of CH at 1700h, to depress rumen pH for at least 3 h/d below 5.6. The average concentrate inclusion for the SARA induction diet was 76±10% DM. During stepwise adaptation, time with pH below 5.6 increased to an average of 121 min/d when the steers were consuming a diet containing 61% DM as WBP. Dietary inclusion of WBP at the rate of 76% DM induced SARA because the steers spent an average of 219 min/d with pH below 5.6. The free ruminal lipopolysaccharide (LPS) concentration increased from 6,310 endotoxin units (EU)/mL with the all-forage diet to 18,197 EU/mL with the 61% concentrate diet. The ruminal LPS concentration increased to 26,915 EU/mL when SARA was induced. Serum haptoglobin increased from 0.53 mg/mL when steers were on the all-forage diet to 1.90 mg/mL with the 61% concentrate diet and were not increased further by inducing SARA. The serum amyloid-A concentration was not affected by increasing dietary concentrate during stepwise adaptation to the concentrate, but increased from 71 to 163μg/mL when SARA was induced. A gradual increase in dietary concentrate so that the F:C ratio decreased to 39:61 resulted in increased ruminal LPS concentrations. Subsequent induction of SARA further increased ruminal LPS and activated an inflammatory response.