Chicks that were challenged with E. acervulina on d 14 had
lower rates of weight gain (Table 2) during the subsequent
week compared with control chicks (P 0.02) and they
tended to have decreased feed intake (P 0.06) and efficiency
of feed utilization (P 0.08). Dietary betaine did not affect
body weight gain, feed intake or efficiency of feed utilization in
the weeks preceding the challenge with E. acervulina.
Betaine concentrations in the duodenal epithelium were
7.2 and 10.9 mmol/L in chicks consuming 0.5 and 1.0 g
betaine/kg diet, respectively. The betaine concentration in the
jejunal epithelium was 3.0 mmol/L in chicks consuming 1.0 g
betaine/kg diet. Betaine levels were below the limit of detection
(1.0 mmol/L) in jejunal and ileal epithelia of chicks
consuming all other diets. Plasma betaine concentrations increased
(P 0.01) with increasing dietary betaine levels (Fig.
1). Challenge with E. acervulina decreased plasma betaine
concentrations (P 0.01), but an interaction between dietary
betaine level and E. acervulina (P 0.04) was observed
because plasma betaine concentrations decreased in chicks fed
0.0 or 1.0, but not in chicks fed 0.5 g betaine/kg diet.
Challenge with E. acervulina increased (P 0.01) the
osmolarity of the duodenal and jejunal epithelia (Table 3).
Dietary betaine at 0.5 g/kg significantly decreased the osmolarity
of the duodenal epithelium compared with the 0.0 g/kg
treatment. The decrease in osmolarity due to betaine tended
to be more pronounced in chicks challenged with E. acervulina
(P 0.07 for betaine by E. acervulina interaction).