M. L. Sunde

The stimulation of 25-hydroxyvitamin D3-1α-hydroxylase by estrogen☆

Abstract Homogenates of kidney from laying Japanese quail incubated in vitro with 25-hydroxy-[26,27- 3 H] vitamin D 3 produce more 1,25-dihydroxy-[26,27- 3 H]vitamin D 3 than do homogenates of kidney from mature nonlaying females or males maintained on the same diet and under identical conditions. Instead, the homogenates from male quail or nonlaying female quail convert 25-hydroxyvitamin D 3 to 24,25-dihydroxyvitamin D 3 . The administration of 5 mg of estradiol to mature male quail 24 h prior to sacrifice suppressed the 25-hydroxyvitamin D 3 -24-hydroxylase and markedly stimulated 25-hydroxyvitamin D 3 -1-hydroxylase. The administration of estradiol to male quail caused hypercalcemia, which responded more slowly than did the 1-hydroxylase. As little as 0.1 mg of estradiol/quail was found effective in stimulating the 1-hydroxylase and suppressing the 24-hydroxylase. Other hormones such as follicle stimulating hormone (FSH), cortisone, testosterone, and progesterone, even at high dose levels, produced little or no change in the 25-hydroxyvitamin D 3 -1-hydroxylase. Testosterone did, however, suppress the 25-hydroxyvitamin D 3 -24-hydroxylase. The stimulation of the 25-hydroxyvitamin D 3 -1-hydroxylase by parathyroid hormone was of a smaller magnitude than that of the estradiol, and the effects of the two hormones were additive, suggesting that they function by a different mechanism.

Interaction of dietary antibiotic supplementation and stocking density on broiler chick performance and immune response.

The growth depression caused by reducing the space allowance in battery brooders from 0.047 to 0.019 m2 per chick was ameliorated by subtherapeutic inclusion rates of dietary antibiotics. However, the interaction of antibiotic supplementation and stocking density was not significant for the variables measured. Increasing stocking density improved the efficiency of food utilisation. The high density regimen resulted in decreased weights of the bursa and thymus relative to body weight but there was no concurrent reductions in antibody response, spleen weight or mortality.

Hatching Eggs Sanitized with Chlorine Dioxide Foam: Egg Hatchability and Bactericidal Properties

The efficacy of chlorine dioxide (ClO2) as an alternative sanitizing agent for hatching eggs was investigated because of the health concerns about formaldehyde fumigation. Hatchability of chicken eggs was reduced when the eggs were dipped in the ClO2 solutions for more than 5 minutes or in concentrations greater than 100 ppm Cl. However, treating hatching eggs with a ClO2 foam or fumigating with formaldehyde had no adverse effect on hatchability compared with untreated control eggs. Sanitizing soiled duck eggs with ClO2 foam improved hatchability by more than 10% and hatch by more than 6% compared with untreated eggs (P less than 0.05). A novel method for assessing bactericidal potential of egg-sanitizing agents was developed. Using this technique, both chlorine dioxide foam and formaldehyde fumigation reduced the number of egg-contaminant bacteria inoculated on sterile chicken eggs compared with the number of bacteria on untreated eggs (P less than 0.05). These findings suggest that sanitizing hatching eggs with ClO2 foam may be a viable alternative to fumigating with formaldehyde.

Effect of Histamine, Histidine, and Some Related Compounds on the Zinc-Deficient Chick.∗

Summary Histidine at 1.0% and 2.0% of the diet, or histamine at 0.2% of the diet prevented the “arthritic-like” or “perosis-like” syndrome in zinc-deficient chicks fed soy protein diets, while having little or no effect on other symptoms of zinc deficiency. Other histidine metabolites and related compounds such as urocanic acid, β-imidazole acetic acid, imidazole and thiolhistidine had little or no effect on the zinc-deficient chick. A direct histidine-histamine relationship is postulated. The authors acknowledge the assistance of Wayne M. Becker in writing the programs used in the statistical analysis of these experiments.

Support of embryonic chick survival by vitamin D metabolites.

The provision of 1,25-dihydroxyvitamin D3 as the only source of dietary vitamin D3 to laying hens failed to support normal embryonic development in their fertile eggs. Significant (P less than .001) improvement in embryonic survival to hatching in these eggs resulted from injections of 1,25-dihydroxyvitamin D3, 24,25-dihydroxyvitamin D3, 25-hydroxyvitamin D3, or 24,24-difluoro-25-hydroxyvitamin D3 prior to incubation. Maximum embryonic survival with lowest embryonic mortality was observed when 0.20 micrograms/egg of 1,25-dihydroxyvitamin D3 or 0.60 micrograms/egg 25-hydroxyvitamin D3 was injected. These results indicate that several forms of vitamin D, two of which cannot be converted to 24,25-dihydroxyvitamin D3, can provide this activity; and of the vitamin D compounds tested, 1,25-dihydroxyvitamin D3 may be the most active in supporting embryonic survival in the chick when delivered directly by injection.

Influence of culture filtrate ofTrichoderma viride and barley on lipid metabolism of laying hens

The suppression of hepatic 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase and cholesterol 7 α-hydroxylase, previously noted in studies of the influences of barley and the filtrate ofTrichoderma viride culture (CF) on cholesterol metabolism in sexually immature birds, is shown in sexually mature birds. Barley, CF or both were fed in one study from the day of hatching, in another during the period of sexual maturation and, in a third study, CF was fed to mature layers. CF suppressed HMG CoA reductase by 30–50% and cholesterol 7 α-hydroxylase by 32–45% when added to the control diet. In birds fed barley rather than corn, the respective activities were 25–36% and 24–31% lower. These effects were expressed in the lowering of plasma cholesterol by 11–36%. Lipogenic activity based on the assays of 4 enzymes was increased 2–3 times by the treatments and plasma triglyceride elevated by 12–86%. The start of egg production by birds fed CF preceded the controls by 17 days. Birds fed barley trailed controls by 11–14 days. CF countered the barley-conditioned delay. Egg yolk cholesterol concentrations were lowered by both treatments. Eggs produced by hens fed barley were lower in weight; CF increased egg and yolk weights. Tissues from birds fed CF or barley for up to 30 weeks appeared to be normal.

Sensitivity of chick embryo to various solvents used in egg injection studies

Abstract Two experiments were conducted to study the sensitivity of developing chicken embryos to various solvents used as vehicles and their effect on hatchability. No significant differences on embryonic mortality were observed between the sham-injected control and corn oil-injected groups. Acetone, ethylene glycol, and ethanol (0.10 ml/egg) significantly reduced the percentage hatchability and showed a high embryonic mortality during the first week of incubation. Levels of cottonseed oil (0.05-0.10 ml) and propylene glycol (0.05-0.15 ml) were well tolerated by the developing embryo but were slightly inferior to corn oil. Levels of 0.05-0.15 ml of corn oil are suitable vehicles for fat soluble compounds in studies involving the injection of eggs. Higher levels of solvent can be injected at later incubation periods. The choice of the best solvent must be made depending upon (1) solubility of test material, (2) amount of test material needed, (3) toxicity of the solvent at the appropriate levels, (4) route of administration, and (5) stage of development.

Zinc Deficiency in Pheasant Chicks Fed Practical Diets

A disease syndrome characterized by abnormal feathering and varus deviation of the tarsometatarsus spontaneously occurred in pheasant chicks fed a practical commercially prepared diet. The addition of supplemental Zn to the commercial diet was effective in alleviating the clinical signs, even though the commercial mix had Zn levels that met the published pheasant chick requirement. Supplemental arginine was ineffective in reducing the severity of the clinical signs. Also, when the diet was mixed in a laboratory setting, pheasant chicks did not develop abnormal feathering and leg bones. Clinical signs caused by feeding the commercial mix were not reproduced by altering dietary calcium and phosphorus levels in the laboratory mix. Neither adding a pellet binder nor removing supplemental Zn from the lab mix produced as severe leg and feather deformities as the commercial mix. Thus, unidentified dietary factors are capable of causing a Zn-deficiency syndrome in pheasant chicks fed practical diets with analyzed Zn levels meeting the required levels.

Excessive cholecalciferol in a layers diet: Decline in some aspects of reproductive performance and increased bone mineralisation of progeny

Feeding hens a diet containing 5,000 micrograms (200,000 ICU)/kg of cholecalciferol for four 28-d periods had no adverse effect on hen-day egg production or hatchability. Egg weight, shell quality, food consumption and fertility were significantly decreased in hens fed 5,000 micrograms/kg. of cholecalciferol compared with those fed 24 micrograms (960 ICU) cholecalciferol/kg diet. Plasma calcium increased significantly as the concentration of cholecalciferol was increased in the diet. However, no histologically detectable changes in the viscera or changes in the proportion of bone ash were observed with any concentration of the vitamin. Chicks hatched from dams receiving excessive doses of cholecalciferol (5,000 micrograms/kg) and maintained on a rachitogenic diet for 4 weeks had a significantly higher proportion of tibial ash but there was no effect on either body weight or tibial calcium.

Growth-promoting activity of L-lyxoflavin.

Summary L-lyxoflavin stimulates growth of chicks under these conditions. Its mode of action remains obscure. Since it has no riboflavin activity, and its growth-promoting action occurs on a ration rich in riboflavin, it is quite possible that it acts as a true vitaminlike entity. The possibility that it acts in the same manner as the known antibiotics is unlikely, since the ration contained aureomycin.