2001 Volume 38 Issue 6 Pages J167-J176
Our previous study (part 1) showed that carrot leaf (CL), a farm wasteproduct, fed to laying hens elevated -carotene content and Roche color fan score of egg yolk. The present study was designed to see whether fat inclusion in diets potentiates the CLinduced effects, as described for a chemical product of -carotene. To make diets containing CL isocaloric and to retain -carotene content of CL during its drying, nutrient composition of CL and a useful method to make it dry were determined beforehand. Four diets, a basal diet for laying hens (BDLH, control), BDLH with 5% or 10% added CL, and BDLH with 10% added CL plus soybean oil, were each fed to hens in different blocks for 8 weeks. Supplemental CL had no effect on egg production with a slight reduction in food intake. -carotene content of egg yolk was significantly elevated in blocks fed diets containing CL (P<0.05), and with 10% added CL it was nearly 6 times as high as the control. Neither the CL-induced effect nor the ratio of -carotene retained in egg yolk to the total -carotene intake was increased by supplementation of soybean oil. Roche color fan score of egg yolk was invariably higher in blocks fed diets containing CL than in the control. However, there was no significant difference in the score between 5% and 10% of CL inclusion in diets, suggesting that 5% of CL in diets was high enough to increase the score. Egg weight, haugh unit, eggshape index and strength and thickness of eggshell remained almost unaltered after feeding CL to hens.
These results suggest that CL may be used as a farm product of improving egg quality by which the market value of eggs is elevated, and that the effect of CL is not potentiated by the