Cholesterol profile and gut microbial population of laying birds fed L-Dopa supplemented diets

Abstract

In a 42-day feeding trial, effect of L-Dopa on performance, serum cholesterol and intestinal microbial load in laying birds was investigated. One hundred and twenty 34-weeks-old layers were allotted to 5 dietary treatments of 8 replicates and three birds per replicate. The birds were fed diets supplemented with L-Dopa at graded inclusion levels (0.0, 0.1, 0.2, 0.3 and 0.4% of the diet) in a completely randomized design. Performance parameters were monitored. At day 42, egg, meat and 2.5 mL of blood were sampled to determine total cholesterol and lipoproteins using standard procedures. The ilea digesta was collected for microbial load analysis. Data were analysed at α0.05.

The L-Dopa inclusion had no effect on the performance parameters and egg cholesterol profile. Serum cholesterol levels of birds fed the control diet and those on 0.1% and 0.2% L-Dopa supplemented diets were similar but significantly higher than those fed 0.3% and 0.4% L-Dopa. In meat, the cholesterol and low density lipoprotein of birds fed control diet were significantly higher than 0.1% and 0.3% L-Dopa but similar in birds fed other diets. Also, Escherichia coli population was highest (7.25 x10⁴cfu/mL) in birds on control diet and least (1.35 x10⁴cfu/mL) in birds fed 0.3% L-Dopa. Lactobacillus counts of birds on L-Dopa supplemented diets were significantly higher than those on the control diet.

In conclusion, L-Dopa, at 0.3% inclusion, significantly improved the cholesterol profile in the blood and meat, reduced the population of Escherichia coli and effectively increased the population of Lactobacillus in laying birds.