Effects of dietary fat source on beta-carotene content in egg yolk and egg yolk color

摘要

Effects of dietary oil source on beta-carotene content in egg yolk and egg yolk color were investigated in laying hens. Twenty seven hens (71-wk-old) were divided into three dietary treatment groups. 1) without fat supplementation (control), 2) supplemented with 5 percent of medium chain triacylglycerols (MCT), 3) supplemented with 5 percent of long chain triacylglycerols (LCT). Those experimental diets contained 0.1 percent of beta-carotene beadlets, and were fed for 28 days. The beta-carotene content of egg yolk increased, and reached a plateau at 7 to 14 days after feeding the experimental diets. At day 21 after feeding, beta-carotene contents of egg yolk from hens fed the LCT, MCT supplemented diets and control diet were 441, 248, and 266 mu g/100 g egg yolk, respectively. Efficiency of egg yolk deposition of beta-carotene (the ratio of beta-carotene retained in egg yolk to beta-carotene intake) of hens fed the LCT, MCT supplemented diets and control diet were 0.59 percent, 0.34 percent, and0.41 percent, respectively, and significantly increased with hens fed the LCT supplemented diet than hens fed the MCT supplemented diet. Yolk color fan score was significantly decreased with hens fed MCT supplemented diet than hens fed LCT supplemented diet. Egg production and feed conversion ratio were not affected by the dietary oil source. These results suggest that beta-carotene content and efficiency of egg yolk deposition of beta-carotene were affected by the dietary oil source, and LCT is more effective to deposit beta-carotene in egg yolk than MCT.