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The present experiment aimed to compare toxic effects of dietary organic or inorganic selenium (Se) and to predict of Se intake and tissue Se concentrations in broiler chickens based on feather Se concentrations. A total of four hundred twenty 7-day-old Ross 308 male broiler chicks were allotted to 1 of 7 dietary treatments in a completely randomized design. Each treatment had 6 replicates with 10 birds per replicate. Organic Se (selenium yeast) or inorganic Se (sodium selenite) was added to the basal diet at the levels of 5, 10, or 15 mg/kg Se. All experimental diets were fed to birds on an ad libitum basis for 28 d. Results indicated that a significant interaction (P

A study was conducted to evaluate the effect of dietary selenium (Se) sources (organic and inorganic Se at 0.30 ppm and basal diet at 0 ppm level of supplemented Se) on hatching traits in four varieties of Aseel chicken, Lakha, Mushki, Peshawari, and Mianwali. In total, 84 adult molted hens (50 wk old), 21 from each variety, were randomly assigned to 12 treatment groups in a 3 (Se diets) × 4 (Aseel varieties) factorial arrangement under a randomized complete block design. Each treatment was replicated 7 times with individual hens in each. Settable egg, fertility, hatch of fertile eggs, hatchability, A-grade chick, and embryonic mortality parameters were evaluated. The results indicated that the birds fed an organic Se supplemented diet had greater (P 0.05) settable eggs, fertility, hatch of fertile eggs, hatchability, and A-grade chicks and reduced embryonic mortality than those fed inorganic or no Se. Among varieties, Mushki had lower (P 0.05) fertility, hatch of fertile eggs, hatchability, and A-grade chicks than rest of three varieties. Interaction of Se sources and varieties indicated that dietary organic Se supplementation improved (P 0.05) hatch of fertile eggs in Peshawari and Mianwali, whereas hatchability only in Peshawari variety and reduced embryonic mortality in Mianwali. It was concluded that dietary supplementation of organic Se could be used to improve hatching traits as well as reduce embryonic mortality in native Aseel chicken.

An experiment was conducted with 192 day-old male Cobb chicks to study tissue uptake of Se as an estimate of the bioavailability of supplemental inorganic Se sources fed at high dietary concentrations. A basal corn-soybean meal diet (.18 mg Se/kg diet, dry matter basis) was supplemented with 0, 3, 6, or 9 mg Se/kg diet (as-fed basis) as either reagent grade Na2 SeO3, CaSeO3, or Na2 SeO3 plus fumed amorphous carrier or 6 mg Se/kg diet as either Na2 SeO4 or Se metal, and fed for 1 wk. No toxic effects were noted as expressed by mortality; however, there was a reduction (P Multiple regression slope ratios were used to estimate relative bioavailability values of 100, 103, 99, 112, and 83 for Na2 SeO3, CaSeO3, Na2 SeO3 + carrier, Na2 SeO4, and Se metal, respectively. When these ratios were corrected for the analyzed dietary Se concentration, relative values were 100, 96, 94, 109, and 81 for the above sources, respectively.

INVESTIGATIONS of the toxic effects of seleniferous grains on hatchability were first reposted by Franke and Tully (1935). Subesquent studies have shown that the feeding of inorganic selenium salts in the laying ration or the injection of small amounts of inorganic selenium into the air cells of fertile eggs, Franke et al 1936, as well as the feeding of seleniferous grains, will as the feeding of seleniferous grains, will produce deformed embryos. Other angles of the effects of seleniferous grains on poultry have also been investigated, Tully and Franke (1936) and Poley et al (1937). In connection with investigations of the “alkali disease” the selenium content of the organs and tissues from several selenzied laboratory animals had been determined by Moxon (1937). The selenium content of the selenized animals indicated that it would be important to investigate the selenium content of eggs and meat from hens fed seleniferous grains. EXPERIMENTAL . . .

IT HAS been shown that the inclusion of seleniferous grain in the rations of laying hens will reduce hatchability of fertile eggs and cause deformed embryos (Franke and Tully, 1935). Similar results have been produced by injecting small amounts of inorganic selenium salts into fertile eggs (Franke et al., 1936). More recently it has been found that arsenic will counteract the toxic action of selenium in rats (Moxon, 1938; Moxon and DuBois, 1939; and DuBois, Moxon, and Olson, 1940), in hogs (Moxon, 1941a), in dogs (Rhian and Moxon, 1943), and in cattle. 1 Arsenic has also been found to be quite effective in counteracting the toxicity of selenium in the diet of growing chicks (Moxon, 1941b). In connection with studies on the mechanism of selenium-arsenic antagonism it was desirable to determine whether arsenic would prevent the reduction in hatchability of chickens eggs when selenium was included in the ration of laying . . .

Practical diets containing various selenium levels, with and without selenite supplementation, were fed to hens. Eggs were then collected over a 14-day period to determine how quickly changes in dietary selenium affected egg white and yolk selenium. Changes in egg white selenium content were rapid and essentially completed seven days after changing the selenium content of a practical diet. Changes in egg yolk were not yet completed by 14 days. When selenium from practical feedstuffs was fed, the selenium content of dried egg white was about equal to or greater than the selenium content of dried egg yolk. When selenite was fed, the selenium content of dried yolk was higher. Feeding selenomethionine resulted in more selenium in egg white than in egg yolk. Feeding selenocystine resulted in more selenium in egg yolk than egg white, a pattern similar to that from feeding selenite. The data suggest that selenocystine is not incorporated into protein but is metabolized to an inorganic selenium compound.