水産および畜産生産

抽象的な

Supplemental Red Alga, Gracilaria vermiculophylla, from a Brackish Japanese Lake, Strengthens Egg shells and Improves the Haugh unit of Eggs in Laying Hens

Hiroaki Ozaki, Masanori Kawahara, Ryuichiro Nogami, YuzoYamada and Hideaki Takahashi

The red alga, Gracilaria vermiculophylla (called Ogonori in Japanese), is overabundant in the brackish Nakaumi- Lake, fifth-largest lake for surface area in Japan. The algal decomposing caused the lake water pollution. The aim of the present study was to examine if the Ogonori can be used as food additive for laying hens, for this reason, a crossbreed between Japanese Game sires and Rhode Island Red dams was used. Thirty hens were randomly chosen from the cross bred birds and evenly distributed into two groups: control and Ogonori group at 63 weeks of age. The control group was alimented with a diet formulated to satisfy the nutrients requirements of the Japanese Feeding Standard for Poultry. For the Ogonori group, the algae were harvested from Nakaumi Lake, washed in fresh water, sun-dried, freezedried, and ground to a meal. Ogonori meal was added to the control diet as 2% of fresh matter. Each chicken was fed with 140 g/day from 63 to 65 weeks (wks.) of age. Egg traits were measured, including egg weight, eggshell weight, eggshell thickness, yolk weight, albumen height, eggshell strength, and yolk color, for the first three eggs obtained each individual from 64 to 65 wks. Haugh unit, egg specific gravity, and albumen weight were also calculated. Eggshell strength and thickness were significantly higher in the Ogonori group than in the control. Albumen height and Haugh unit were significantly higher in the Ogonori group than in the control, although there was no significant difference in albumen weight between the two groups. These data suggest that Ogonori can be used as a feed additive for laying hens to improve the economically important egg traits. The mineral profile of Ogonori meal suggested an association between eggshell and albumen traits and high contents of minerals (manganese, iron, chromium, and aluminum).