Application of a new red carotenoid pigment-producing bacterium, Enterobacter sp. P41, as feed supplement for chicken
In order to use purple non-sulfur bacteria as feed supplement in chicken industries, screening for red pigment-producing bacteria with proteinases was done using hen feces as a target. One isolate, P<sub>41</sub>, with the highest proteinases activity was selected for further studies. Based on the data of biochemical and 16S rDNA sequence analysis, it was identified as Enterobacter sp. P41. This strain produced 0.16 mg of β-carotene with red color per gram of cell dry weight. Addition of the dried cells of Enterobacter sp. P<sub>41</sub> to chicken feeds did significantly intensify the egg yolk color (p = 0.000). Moreover, addition of the dried cells at the amount of 0.45 mg per kg of feed significantly increased the rate of egg-laying (p = 0.029). These results suggest that the dried cells of Enterobacter sp. P<sub>41</sub> might be useful as feed supplement for hens or other avian.
Key words: β-Carotene, Enterobacter sp., red carotenoid pigment, egg yolk, egg-laying rate, proteinase.