Effect of micronutrient (L-tryptophan) imprinting on growth performance, fecal consistency, and blood parameter of Hanwoo calves

초록

This study investigated the effects of rumen-protected L-tryptophan supplementation (micronutrient imprinting) on the growth performance, fecal consistency, and immunity of Hanwoo calves. Ten newborn Hanwoo calves (birth weight: 29.5 ± 3.8 kg) were randomly assigned for 120 days to the following two groups: the control group fed with a basal diet (formula feed + annual ryegrass), and the treatment group fed with a basal diet + rumen-protected L-tryptophan (0.1% of formula feed). Average daily weight gain during the entire period was significantly higher in the treatment group than in the control group (P < 0.05). The fecal scores were significantly higher in the control group in the duration from birth to 1 month and from 2 to 3 months of age (P < 0.05). The plasma magnesium concentration was significantly higher in the treatment group than in the control group (P < 0.05), while other blood metabolites and complete blood counts were similar for both groups. The concentrations of immunoglobulin A and M showed a tendency to increase in the treatment group as compared to the control group. Thus, our results indicate that rumen-protected L-tryptophan supplementation has a positive effect on immunity and is effective in improving the fecal score and growth performance of Hanwoo calves.

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