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Schizochytrium sp. and lactoferrin improve intestinal health of dairy calves challenged with Escherichia coli K99.

L. Ma

Events

06-22-2020

Abstract:

141
Schizochytrium sp. and lactoferrin improve intestinal health of dairy calves challenged with Escherichia coli K99.
A. L. T. Zhu La1, W. H. Liu1, L. J. Ren1, S. T. Gao1, Z. T. Yu2, D. P. Bu1, L. Ma*1. 1State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences Beijing, China, 2Department of Animal Sciences, The Ohio State University Columbus, OH.

Calf diarrhea is a common intestinal disease, and Escherichia coli is the main causative agent. The aim of this study was to evaluate Schizochytrium sp. (SZ) and lactoferrin (LF) for their ability to protect intestinal health of dairy calves challenged with Escherichia coli K99. Forty newborn male Holstein calves (1 d old, 39.9 � 4.5 kg initial BW) were randomly assigned to 1 of 4 groups (n = 10): 1) Ctrl: control fed whole milk only; 2) LF: fed whole milk supplemented with lactoferrin (1 g/d); 3) SZ: fed whole milk supplemented with Schizochytrium sp. (20 g/d); and 4) LF+SZ: fed whole milk supplemented with both lactoferrin (1 g/d) and Schizochytrium sp. (20 g/d). The SZ and LF were added to whole milk (protein: fat ratio, 3.64%:4.20%) immediately before feeding and fed daily to each calf from d 2 to 14. At d 7, all the calves were challenged with Escherichia coli K99 (1 � 1010 cfu/mL) once orally. During the experiment, milk and starter feed intake and fecal scores were recorded daily, while BW (BW) was weighted at d 1, 7, and 14. Blood was sampled after the afternoon feeding from the jugular vein at d 7 and 14. Statistical analysis was performed using SAS v. 9.4 with SZ, LF, the interaction of SZ and LF, week, and the 2- and 3-way interactions of SZ, LF, and time as fixed effects. Compared with the control, LF lowered fecal score (2.05 vs 2.30, P < 0.05) and nitric oxide concentration in serum (1.63 vs 1.99, P < 0.05), while SZ increased immunoglobulin G (IgG) concentration (1,357.23 vs 1,341.91, P < 0.05), tended to increase the concentration of interleukin-10 (IL-10) (81.99 vs 77.65, 0.05 < P < 0.1) and to reduce the concentration of tumor necrosis factor-α (TNF-α) (163.15 vs 166.47, 0.05 < P < 0.1) in serum. The combination of LF and SZ (LF+SZ) tended (2.05 vs 2.30; 0.51 vs 0.60, 0.05 < P < 0.1) to lower fecal score and serum lipopolysaccharide concentration but lowered blood D-lactic acid concentration in serum (3.31 vs 3.50, P < 0.05). These results indicate that SZ could improve the immunity and anti-inflammatory activities, reduce intestinal permeability and pro-inflammatory activities, and decrease fecal scores in dairy calves, while LF could reduce fecal scores and intestinal permeability. A synergistic effect was shown by this study between LF and SZ in decreasing fecal score and intestinal permeability, which can effectively alleviate diarrhea in dairy calves.

Keywords: Schizochytrium sp., lactoferrin, dairy calves.