RESUMO
This study investigated the effects of dietary supplementation with vitamin E (vit. E), selenium yeast (Se yeast), or both on egg incubation response, embryonic development, keet quality, and posthatch growth of helmeted guinea fowls. Two hundred and forty 24-week old helmeted guinea fowl hens (average weight 1.75 + 0.22 kg) and cocks (average weight 2.15 + 0.20 kg) were assigned into 24 pens; each pen housed 10 hens and 2 cocks. There were four dietary treatments consisting of a basal diet (control), basal diet supplemented with vit. E (30 IU/kg), Se yeast (0.3 mg/kg Se), or both. Six pens were assigned to each treatment. Egg incubation response were estimated using 504 settable eggs sampled from each treatment collected during 15 to 17 weeks in lay. A total of 72 fertile eggs sampled from each treatment were used for the estimation of embryonic development. Quality of day-old keets hatched was scored based on physical conditions, while posthatch growth was measured for 21 days. Guinea fowl breeders fed diet supplemented with both vit. E and Se yeast produced the highest (P < 0.05) number of fertile eggs, percentage fertility, number of hatchlings, hatchability of total eggs, and hatchability of fertile eggs. Supplementation with vit. E + Se yeast resulted in the heaviest (P < 0.05) embryo weight, relative embryo weight, least (P < 0.05) yolk sac weight, and relative yolk sac weight on 25 days of incubation. Hatchlings from breeders fed diet supplemented with Se yeast and vit. E + Se yeast showed normal swallowed yolk. Supplementation of maternal diet with vit. E, Se yeast, and vit. E + Se yeast resulted in improved (P < 0.05) feed conversion ratio of subsequent hatchlings during 1 to 7-day posthatch growth. It can be concluded that dietary supplementation of vit. E + Se yeast in guinea fowl breeders resulted in improved egg fertility, hatchability, heavier embryo weights, hatchlings of good quality, and improved posthatch growth during the first 7 days.
