R. L. Shirley

Effect on rumen bacteria of methionine hydroxy analog and sulfur-containing amino acids, in vitro.

Summary Fermentation of glucose by rumen bacteria utilizing urea as the only source of nitrogen was carried out with or without MHA. The logarithmic growth rate was observed to increase about 2.5 times due to MHA. The lag phase was markedly stimulated in regard to bacterial N synthesis but not to total bacterial dry matter production. Bacterial activity generated a more negative redox potential than MHA making it improbable that MHA functioned as a reducing agent aiding in the anaerobiosis of the medium. The free hydroxyl group or the Ca salt of MHA were not essential for the stimulatory effect of MHA on bacterial growth. Inorganic sources of sulfur or amino acids other than the sulfur-containing amino acids did not have a growth-stimulating effect as measured at 4.5 hr of fermentation. Cystine, cysteine and methionine individually stimulated bacterial growth similar to that of MHA. These observations indicated that any of the sulfur-containing amino acids or MHA can be rapidly converted to the other sulfur-containing amino acids, but the synthesis of the sulfur-containing amino acids from inorganic sulfur is a rate-limiting process for growth of rumen bacteria metabolizing a readily available carbohydrate.

Reproduction and Lactation in Rats Fed Excessive Iodine

In a series of experiments adult female rats were fed zero to 2500 ppm supplemental iodine from zero to approximately 35 days prepartum. Females were permitted to litter normally and the survival of the young was observed. Other females were killed either between 17 and 19 days of pregnancy or between 24 and 48 hours postpartum to observe ovulation rate, implantation rate, development of normal fetuses and histology of mammary tissue. Increasing mortality of young after birth occurred with increasing levels of iodine. Most young failed to survive for 24 hours and those that survived 48 to 72 hours postpartum usually survived until weaning. Those failing to survive had essentially no milk present in the stomach. Visual observation and histological examination of mammary tissue from females fed iodine revealed that secretion was absent or markedly diminished. The role of iodine in thyroid function and the manifestations of iodine deficiency in various species have been well estab lished and have been reviewed by Riggs (1) and Berson (2). The effect of exces sive iodine, however, is less clearly defined. Morrison (3) reported that excessive in take of iodine is injurious to animals but did not describe the effects, indicate the levels of iodine required, or cite the ex perimental evidence. Malan et al. (4, 5) reported that 200 mg KI daily had detri mental effects on reproduction in sheep; however, the authors stated that the condi tions under which reproductive failure occurred involved not only high levels of iodine but déficiencesof both phosphorus and vitamin A. Other effects of excessive iodine on reproduction have not been re ported, although reproductive abnormali ties have been attributed to iodine defi ciencies (6, 7). The present studies were conducted to determine the effects of various levels of dietary iodine upon reproduction and lacta tion of rats.

Blood Changes in Turkeys Associated with a Copper Deficiency.

Summary Day-old turkey poults were fed 5 levels of supplemental copper for 6 weeks. There was a significant stimulation of growth in those fed 1.32 to 3.96 ppm of added copper. Microhematocrits of all turkeys were within normal ranges. The erythrocytes of birds fed 1.32 ppm of supplemental copper had abnormally shaped nuclei, while those of poults fed 1.98 and 3.96 ppm of copper were normal. Nuclear changes consisted of lobulated nuclei, duplication of nuclei, forked nuclei and other bizarre manifestations. Heart and liver cytochrome oxidase activity was greater in those birds fed 1.32 to 3.96 ppm of added copper.

Gamma Irradiation and Interrelation of Dietary Vitamin A and Copper on their Deposition in the Liver of Swine

A study was made to determine whether dietary vitamin A had an effect on the level of deposition of Cu in liver; whether dietary Cu had an effect on the deposition of vitamin A in the liver; and whether whole-body gamma irradiation had any effect on the deposition of vitamin A and Cu in the liver of swine. Vitamin A unsupplemented pigs had only 2 to 3 N of vitamin A/g fresh weight of liver. High vitamin A values (116 to 122 IU/g) in the liver of supplemented pigs demonstrated the remarkable capacity of the liver to store vitamin A when it is present in the diet. Whole-body Co/sup 60/ irradiation with 630 r had no significant effect on the deposition of vitamin A in these tissues. Swine that received no supplemental vitamin A had a greater concentration of Cu in liver, and irradiation resulted in a greater deposition of Cu in the liver. However, dietary vitamin A and irradiation did not affect deposition of Cu in heart and gracilis muscle. Cu supplementation increased the level of vitamin A in liver, possibly on account of the effect of CuSO/sub 4/ in eradicating intestinal parasites. (TCO)

Effect of gamma irradiation on pigs fed low vitamin A rations.

Summary 1. Pigs irradiated with 350 r bilaterally at the rate of 11 r per minute 9 feet from source survived an average of 254 hours. 2. A moderate Vit. A deficiency had no effect on irradiation damage; in fact, the Vit. A low pigs lived an average of 2 days longer. 3. Pigs fed low levels of Vit. A and with very low liver and blood Vit. A levels showed no gross manifestations of a deficiency of Vit. A. Feed intake and growth rate were fairly normal. 4. Irradiation lowered the total white blood cell count rapidly. 5. The major symptoms of irradiation damage were: (a) depression, (b) skin hemorrhages, (c) hemorrhaging from eyes and mouth, (d) increased respiration, (e) mild muscular spasms just prior to death, (f) extensive hemorrhage of lymph nodes plus varying amounts of hemorrhage in the kidneys, heart, urinary bladder, intestine and stomach.

Oxidation, Potentials, Buffering, Ash, and Total Solids of Peaches

1. Several varieties of peaches, grown on both limestone and sandstone soils in the Shenandoah Valley, were studied by determining the amount of ceric ammonium nitrate oxidizing reagent they would reduce, as well as their potential, pH ranges of buffering, ash, and total solids at different stages of growth. 2. The varieties grown on the sandstone soil had less reducing capacity during growth and at maturity showed a decrease that was not characteristic of those grown on the limestone soil. As far as the authors know, this is the first time that a fruit has been evaluated by oxidation with the ceric ion. 3. Varieties of peaches grown on the sandstone soil had slightly greater potential than the ones grown on the limestone soil, indicating that they were in a higher oxidation state. They showed less ash during stages 1 and 2 of growth but essentially the same at maturity and showed more total solids in all stages of growth. 4. Buffer capacity was greatest between the initial pH and 6.0, least between pH 6.0 to 8.0, and an intermediate amount between pH 8.0 to 10.0. On approaching maturity, buffering decreased in all ranges with each variety tested.

Reducing Capacity, Potentials and Water of Apples

Apples of the York Imperial, Rome Beauty, Red Delicious and Golden Delicious varieties have been evaluated for their capacity to reduce the ceric ion and oxidation-reduction potentials, during growth and storage, and true water content during storage, at approximately biweekly intervals. Three periods of change occurred in reducing capacity throughout growth and storage. No direct relation was obtained between the ceric ion reducing capacity of the apples and the concentration of reducing sugars present. The difference in potentials between the growing and storage periods was significant at the 0.05 level; such evaluations should be a measure of the oxidative state of the fruit. True water evaluations by toluene distillation and water traps were shown to be significantly lower than those obtained by oven drying.