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چکیده
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There is increasi ng concern about welf are of laying hens in cages, and one aspect of this topic relates to bone fragili ty. The refore, 9 bone an abolic compo nents such as bovine lactoferrin (bLF) may be an effective strategy to maint ain the integ rity and health of 10 bones. A total of 1080 eggs were divided into four groups w ith three replic ates, each comprisi ng 270 eggs; (1) contro l group was 11 inject ed w ith 100 μ l of norm al saline per egg; (2, 3 an d 4) groups incl uding 22.5 (low), 45 (med ium) and 67.5 µ g (high) of bLF in 12 100 µ l of norm al saline per egg. Eggs were incub ated an d after hatch ing, ch icks were reared to 28 w eeks of age. Tibia 13 measurem ents were obtain ed at hatch and at 28 weeks of age. Tibia w eight at hatc h, was not in fl uenced by in ovo inje ction of bLF 14 in compa rison with the co ntrol. Egg s inje cted with the high concen tration of bLF (67.5 µ g of bLF per egg) showed sign i fi cant 15 streng thening in laying-hen tibia s at 28 weeks of age , as mea sured by ultimate force and bendi ng stress, compa red with the 16 contro l. Egg weights from hens treated w ith thi s conc entration of bLF were also signifi cantly greater than the contro l. Our data 17 suggest that tib ia co rtical thickn ess is a suitable variabl e for evalua ting bone status re fl ecting bon e integ rity and strength. The 18 present study also show s that bLF (67.5µ g of bLF per egg) inje cted into layer breeder eggs before incubation can be used to 19 improve bone stren gth and egg w eight of laying hens at 28 weeks of age, while having no detrimen tal effect on embryo 20 hatch ability.
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