PSI-27 Feeding corn grain steeped in citric acid modulates rumen fermentation and inflammatory responses in dairy goats.

Abstract

The objectives of this study were to evaluate the effects of feeding ground corn steeped in citric acid on ruminal fermentation, milk production and immunity responses in dairy goats. Eight ruminally cannulated Saanen dairy goats (BW 32.5 kg) were used in a crossover experiment. Each experimental period was 21-day, including 14-days adaption and 7-days sampling. The diet contained 30% hay and 70% corn-based concentrate (DM basis). Corn was steeped either in water (control) or in 0.5% (wt/vol) citric acid (CA) for 48 h. Goats fed CA diet showed improved ruminal pH with greater mean (5.93 vs. 5.85) and minimum ruminal pH (5.45 vs. 5.30), and shorter (P<0.05) duration of ruminal pH < 5.6 (156 vs. 317 min/d).Total VFA concentration (63.5 vs.71.4 mM) and molar proportion of propionate (18.7 vs. 19.9%) were lesser (P<0.05) but the acetate (67.1 vs.65.1%) was greater (P<0.05) with CA than control. Ruminal lipopolysaccharide (LPS;20.2 vs. 25.5 × 10³ EU/mL) was lesser (P<0.05) and lactic acid tended (P<0.10) to be lesser in CA vs. control. Although DMI (1.03 kg/d) was not affected, yield of milk fat (26.8 vs. 20.6 g/d) and 4% FCM (0.67 vs. 0.52 kg/d) tended (P<0.10) to be greater in goats fed CA versus control diet. Regarding inflammatory responses, peripheral LPS did not differ (0.06 vs. 0.09 EU/mL), whereas the concentration of LPS binding protein (1.04 vs.1.24 μg/mL) and serum amyloid A (56.9 vs. 110.8 μg/mL) tended (P<0.10) to be less in CA versus control group. Similarly, goats fed CA versus control diet had lesser (P<0.05) concentration of haptoglobin (1.29 vs. 1.83 μg/mL) and tumor necrosis factor (40.3 vs. 95.8 μg/mL). These results indicated that feeding ground corn treated with CA effectively improved ruminal pH status, thus potentially alleviated risk of ruminal acidosis, reduced inflammatory response, and tended to improve milk yield and milk fat.