Effects of clay supplementation on rumen environment, metabolism, inflammation, and performance in dairy cows
Oral supplementation of clay has been reported to function as buffer, an adsorbent, and aid in immune function. However, clays come in a variety of structures and each type has their own properties. Clay supplementation effects on rumen, metabolism, and performance have been considered individually among studies. Our objective was to determine the effects of 3 percentages of dietary clay (EcoMix®) supplementation after two different challenges. Challenge one was to induce sub-acute ruminal acidosis by challenge cows intraruminally with ground wheat and the second challenge introduced corn spiked with aflatoxin directly into the rumen. For the two challenges, 10 multiparous rumen-cannulated Holstein cows [BW (mean ± SD) = 648 ± 12kg] with 142 ± 130 (60 to 502) DIM were assigned to 1 of 5 treatments in a replicated 5 × 5 Latin square design balanced to measure carryover effects. For the acidosis challenge, periods (21 d) were divided into an adaptation phase (d 1 to 18, with regular TMR fed ad libitum) and a measurement phase (d 19 to 21). Feed was restricted on d 18 to 75% of the average of the TMR fed from d 15 to 17 (DM basis) and on d 19 cows received a grain challenge. The challenge consisted of 20% of the DMI as finely ground wheat administered into the rumen through the rumen-cannula, based on the average DMI obtained on d 15 to 17. For the aflatoxin challenge, 10 multiparous rumen-cannulated Holstein cows [BW (mean ± SD) = 669 ± 20 kg] with 146 ± 69 DIM were assigned to 1 of 5 treatments in a replicated 5 × 5 Latin square design balanced to measure carryover effects. Periods (21 d) were divided in an adaptation phase(d 1 to 14) and a measurement phase (d 15 to 21). From d 15 to 17 cows received an AF challenge. The challenge consisted of 100 μg of Aflatoxin B1 (AFB1)/kg of dietary DMI. The material was fitted into 10-mL gelatin capsules (TORPAC, Fairfield, NJ) and administered into the rumen through the rumen-cannula based on the average DMI obtained on d 12 to 14. Treatments for both challenges were: POS, no clay plus grain or AF challenge; three different concentrations of clay (0.5, 1, or 2% dietary DMI) and control (C), no clay and no challenge. Statistical analysis was performed using the MIXED procedure of SAS. Two contrasts CONT1 (POS vs. C), CONT2 (POS vs. the average of 0.5, 1, or 2%) were compared along with the linear and quadratic treatment effects. Overall, the grain challenge was successful in causing sub-acute ruminal acidosis (rumen, POS = 6.03 ± 0.06, C = 6.20 ± 0.06; fecal, POS = 6.14 ± 0.04 C= 6.38 ± 0.04). Clay supplementation had treatment differences or negative incremental area under the curve, pH below 5.6 × h/d, (0.5% = 7.93 ± 0.83, 1% = 8.56 ± 0.83, and 2% = 7.79 ± 0.83) compared to POS (11.0 ± 0.83). Linear treatment effects on rumen and fecal pH showed an increase in pH for increasing clay percentages in the diet. Cows fed clay tended to have higher milk yield (0.5% = 28.8 ± 3.4 kg, 1% = 30.2 ± 3.4 kg, and 2% = 29.1 ± 3.4 kg, CONT2), have higher 3.5% FCM (0.5% = 29.9 ± 3.5 kg, 1% = 34.1 ± 3.5 kg, and 2% = 33.1 ± 3.4 kg), and higher ECM (0.5% = 29.1 ± 3.3 kg, 1% = 32.8 ± 3.4 kg, and 2% = 31.6 ± 3.3 kg) than cows in POS (27.7 ± 3.4 kg, 28.0 ± 3.4 kg, 27.7 ± 3.3 kg, respectively). Cows exposed to AF showed effects in plasma to indicate liver damage i.e. a decrease in aspartate aminotransferase (AST) (C = 84.23, POS = 79.17) and glutamate dehydrogenase (GLDH) (C = 91.02, POS = 75.81). There was a downregulation in hepatic expression of HP and STAT3. Cows supplemented with clay showed a significant decrease in AF excretion in milk (AFM1; 0.5% = 20.83 μg/d, 1% = 22.82 μg/d and 2% = 16.51 μg/d) and AF transfer from rumen fluid to milk (AFM1; 0.5% = 1.01%, 1% = 0.98% and 2% = 0.74%) compared with cows in POS iv (AFM1 = 27.81 μg/kg and AF transfer = 1.37%, CONT2). Similarly, average concentration of AFM1 in milk, (0.5% = 0.35 μg/d, 1% = 0.30 μg/d, 2% = 0.25 μg/kg), AFB1 in feces, (0.5% = 1.79 μg/kg, 1% = 1.52 μg/kg, and 2% = 1.48 μg/kg), and AFB1 in rumen fluid, (0.5% = 0.05 μg/kg, 1% = 0.02 μg/kg, 2% = 0.02 μg/kg) were reduced in cows fed clay when compared with POS (0.43 μg/k, 2.78 μg/kg, 0.10 μg/kg, respectively, CONT2). There also was a linear trend for increased hepatic expression of NFKB1 and TNFA from POS to 2% clay. In conclusion, the effects of SARA and the effects of aflatoxin prove true to their nature, however, clay supplementation appears to alleviate the effects in both challenges.
Clay, Buffer, Acute and subacute ruminal acidosis (SARA), Aflatoxin, Liver, Gene Expression
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign