engleski

Carotenoid content in egg yolk increases with the amount of digestible carotenoids in hen diets differentiated in maize hybrid

Carotenoids in eggs are a group of health- promoting bioactive compounds that contribute to the pigmentation of the yolk. Among the various dietary sources, yellow maize is the only cereal with significant carotenoid content used for laying hen diet. However, the efficiency of pigmentation and the final carotenoid concentration in the yolk largely depend on their release from the maize grain during digestion. Objective of the present study was to investigate the relationship between the digestibility of carotenoids in vitro and their concentration in the yolk of laying hens in vivo. The INFOGEST in vitro method was used to determine the digestibility of carotenoids from 15 maize hybrids. For the in vivo experiment, 225 Lohmann Brown laying hens were allocated into 15 treatment groups in a completely randomized design (15 treatments×5 cages). After the depletion period, hens were fed 15 experimental diets without added pigment, differing only in maize hybrid (60% of diets) for 8 weeks. Eggs were collected every three days until stabilization, and then once a week until the end of the eighth week. The carotenoid profile in maize grains, digesta and egg yolks was determined by the HPLC method. The commercial maize hybrids analysed showed significant differences in total carotenoid content (16.99- 40.14 µg/g DM). The amount of digestible carotenoids averaged (μg/g DM) 6.43 for zeaxanthin, 5.54 for lutein, 0.52 for β- cryptoxanthin, 0.29 for α-cryptoxanthin and 0.27 for β-carotene. Maize hybrid affected (P<0.001) carotenoid profile in egg yolks, as evidenced by the highest levels of zeaxanthin and lutein, followed by β- cryptoxanthin, α-cryptoxanthin and β-carotene (on average 15.98, 12.68, 0.54, 0.50, 0.48 μg/g, respectively). Furthermore, the content of both individual and total carotenoids in egg yolk correlated with the content of corresponding digestible carotenoids in maize (P<0.001). The obtained results indicate that the applied in vitro digestion protocol is suitable for the prediction of carotenoid content in egg yolk in vivo. Since carotenoids in eggs have high bioavailability, increased digestibility of maize carotenoids implies higher yolk content of these compounds in human diet.

Yellow maize ; Laying hens ; Carotenoid digestibility ; Egg yolk

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