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Several dissimilatory, sulfate-reducing bacteria were isolated from the rumen fluid of sheep fed purified diets containing sulfate. One isolate, strain D, was selected for characterization. This organism is a nonsporeforming, obligately anaerobic, mesophilic, nonmotile, gram-negative, straight rod. Cell-free extracts show absorption maxima for cytochrome c3and desulfoviridin, characteristic of Desulfovibrio. Carbohydrates, as a sole carbon source, will support growth. Lactate supports growth in the presence of sulfate, not in its absence, whereas glucose or pyruvate support growth either in the presence or absence of sulfate. The isolate has a deoxyribonucleic acid base composition of 61.2% guanine plus cytosine, which is similar to that of several other species of Desulfovibrio; however, it differs from previously described species in morphology, motility, and carbon source utilization. Cell-free extracts of this bacterium exhibit adenosine 5′-triphosphate-sulfurylase, adenosine-5′-phosphosulfate-reductase, and hydrogenase activity. After incubation of cell-free extracts with adenine 5′-triphosphate and 35SO42-, adenosine-5′-phosphosulfate rather than 3′-phosphoadenosine-5′-phosphosulfate was shown to be labeled, indicating that the pathway of sulfate reduction in this organism is similar to that of other dissimilatory sulfate reducers. This is the first report of a Desulfovibriosp. isolated from the rumen.Images

A modification of the Norman-Jenkins (1933) method for the determination of cellulose in plants and in feedstuffs is described.Analyses of various legumes and grasses are given which indicate that this method has certain advantages over other methods for estimating the relatively indigestible carbohydrate fraction of feedstuffs.

A procedure for the routine determination of lignin in feedstuffs is givenStudies with the cow, sheep, and rabbit indicate that lignin as determined by this method is not digested.A lignin ratio technique for the determination of the digestibility of feedstuffs is described, and data are presented to show the reliability of this technique.The use of lignin and of cellulose values in a scheme for the analysis of feedstuffs is discussed in the light of data obtained from digestion trials with animals.

Washed rumen microorganisms were investigated under conditions conducive to sulfate reduction, giving the following results: Molybdate inhibits the reduction of sulfate to hydrogen sulfide. Molybdate inhibition increases as the concentration of sulfate decreases. Molybdate has little effect on sulfite reduction. In the presence of copper, molybdate inhibition is markedly decreased.

Phosphate fertilization of soybean hays grown on a Bladen silt loam soil deficient in phosphorus produced no significant change in composition as measured by standard feedingstuffs analysis, which included calcium and phosphorus. This was also true of the bull grass contaminant. Fattening trials and digestibility studies with lambs using soybean hay for roughage and raw soybeans for concentrate gave no significant differences either in weight gains or apparent digestibilities between feeds from phosphate-fertilized and those from non-phosphate-fertilized plots. When cerelose replaced soybeans as the concentrate, lambs which received soybean hay fertilized with phosphate gained an average of .282 pound daily per lamb as compared to .192 pound for the non-phosphate group. This difference was significant at the 5 percent level. Digestion studies using soybean hay alone as well as with cerelose as the concentrate on a second hay crop gave a significantly higher apparent digestibility for the protein of hay from the phosphate-fertilized plots. This was shown to be related to the quantity of protein rather than the quality of protein. Serum phosphate values and digestibility of ash by lambs fed hay from phosphate-fertilized plots plus cerelose were higher than those lambs receiving hay from non-phosphated plots plus sugar. Generalizations on the influence of fertilization on the nutritive value of plants for animal feed are not warranted at this stage of the investigation.

One hundred and forty-eight first-litter gilts and 40 second-litter sows were used in four trials to study the influence of two levels of energy and two levels of protein intake during gestation on gain and reproductive performance. The treatments were 3 or 6 lb. of feed daily, containing either 0.3 or 1.2 lb. of protein. Energy was supplied by corn starch, sugar and fat and protein was supplied by soybean meal (50% protein). Vitamins and minerals were fed to provide an equivalent daily intake for all treatments. All gilts were placed on experiment individually at the time of breeding and were fed in confinement.Gilts fed the high energy level gained significantly more weight during gestation than those fed the low energy level. The low energy level fed during gestation appeared to be adequate for reproduction and apparently did not greatly hinder lactation performance as measured by litter weight at weaning.In trial 1, gilts fed the low energy level farrowed significantly more live pigs while, in trial 2, gilts fed the high energy level farrowed more pigs and the litters were significantly heavier at birth. In trials 3 and 4 there was no significant difference in live pigs farrowed between feeding levels. In each of the four trials, heavier pigs were farrowed by gilts receiving the higher energy intake. Level of energy intake during gestation did not significantly influence pig survival, number of pigs weaned or litter weight at weaning. Level of protein did not significantly affect reproductive performance as measured by number of pigs farrowed, birth weight, pig survival, or litter weight at weaning.

Thirty-four Hereford calves were used in two experiments to determine the feasibility of feeding all-concentrate rations to beef cattle. In the first experiment which was a growth-performance study, a basal diet containing 1.5% fiber and composed of ground shelled corn, urea, cottonseed oil, minerals and vitamins was compared to a similar diet with sodium and potassium bicarbonate added at a level of 11% of the total ration. This level of cation supplementation proved to be excessive; however, performance on the basal diet (1.89 lb. daily) stimulated a second experiment. In this study which included carcass evaluation as well as growth-performance, the basal diet was supplemented with either 5% sodium and potassium acetate or 2.5 lb. per day of ground or long hay. Performance of calves on the unsupplemented basal ration equaled that of calves fed any of the other three diets. Feed conversion on the basal ration alone was slightly superior to conversion on diets containing acetate salts or hay in either form. The presence of acetate salts in the diet adversely affected growth-performance and produced carcasses with less finish than the other three diets. On the basis of these data, it was concluded that calves are able to perform satisfactorily on all-concentrate rations for extended periods of time if the ration provides essential nutrients in adequate amounts and the buffering capacity of the rumen is adequate. The possible rumen buffering capacity of ammonium ions from urea is discussed. Types and levels of buffering agents in all-concentrate rations for ruminants merit further study.

Artificial drying (60° C.) decreased the digestibility of the protein (P=.01) and the lignin (P=.05) of Ladino clover, tall fescue, and orchard grass. The crude fiber of the orchard grass and the fescue was more digestible following drying. Drying increased the digestibility of the nitrogen-free extract of the fescue, while decreasing its digestibility in the clover. The digestibility of the ether extract and the dry matter were not appreciably affected by drying. In the same experiment, rabbits digested all the nutrients of Ladino clover to a greater extent than they did those of either tall fescue or orchard grass. The ether extract and the protein of the fescue were more digestible than those of the orchard, whereas the crude fiber was more digestible in the orchard grass. Digestibility of the dry matter, nitrogen-free extracts, and lignin and the total digestible nutrients were not significantly different in the grasses. The lignin of the clover was 24.1 percent digestible.

For approximately the first 36 hours of life, neonates of some species, e.g., piglets, are able to absorb large molecules from their intestines. The time when the piglet ceased absorbing large molecules (closure) was a function of feeding regimen. Closure activity was in sow's and cow's colostrum. A diet containing protein in a simple salt solution (either egg albumin, porcine albumin or procine γ-globulin) did not render the piglet's gut impermeable to large molecules. Nor was milk fat needed in the diet for closure to occur. A diet of boiled (essentially protein- and fat-free) cow's colostral whey engendered closure. Also, closure activity was in a dialyzate of cow's colostrum and in a dialyzate of non-fat dried milk solids. No activity was associated with synthetic milk salts, vitamins or sugars. Thus, closure is possible with a heat-stable, low molecular weight, protein- and fat-free fraction of milk; and activity is not dependent on the absorption of large molecules.

It has been demonstrated with agar and immunoelectrophoresis that the protein absorption mechanism operating within the first 36 hours of a piglet’s life is qualitatively nonselective. Proteins from such phylogenentically different sources as chickens and cows, as well as different kinds of proteins (albumins and globulins), were absorbed by the neonatal pig. The nonselective nature of this absorption mechanism was emphasized further by the fact that a synthetic, high-molecular-weight, blood plasma extender (polyvinylpyrrolidone) also was absorbed by the piglet during this initial phase.

The chemical similarities between copper, zinc, and cadmium led to the speculation that there existed a copper component of cadmium toxicity in addition to the previously shown zinc component. Cadmium was found to be toxic to chicks at dietary levels of 25 to 400 ppm in a copper- and iron-deficient diet. The toxicity resulted in a reduced growth rate, mortality, microcytic hypochromic anemia, and atony and elongation of the gizzard. The growth depression and gizzard abnormality were corrected by increased dietary zinc. The mortality was reversed by added copper indicating that the speculation which prompted the study was valid. Increased dietary iron partially corrected both the mortality and the growth depression, indicating a previously unsuspected iron component of cadmium toxicity.

A series of experiments was conducted with rats to characterize further the effects of high dietary zinc (0.75%) on iron metabolism. It was found that the red blood cells from animals fed a diet high in zinc were irregularly shaped and microcytic and hypochromic. The osmotic fragility of the red blood cells from the zinc-fed rats was greater than that of the control rats. The zinc content of the blood of the former group was more than twice as high as that of the controls. Blood cells of rats fed the diet high in zinc had a life span (utilizing glycine-2-14C) one-third of that of the controls. By means of 55Fe studies, it was shown that iron incorporation into heme was not affected by zinc toxicity. 59Fe studies showed that the greater turnover of red blood cells for the animals fed the zinc-supplemented diet brought about a greater loss of red blood cell iron via the feces. From the results of this study and those of a previous report, a hypothesis was developed rationalizing the effects of zinc toxicity on iron metabolism.

A series of experiments was conducted to determine the nature of the effect of high zinc diets on iron metabolism. The rats used in all studies were fed a basal diet or the basal + 0.75% zinc. In the initial study radioisotope experiments with 59Fe were conducted to determine whether zinc was interfering with iron absorption. Results indicated that orally administered radioactive iron was absorbed equally by the 2 groups. Subsequent studies showed that the high zinc intake reduced both the amount of ferritin and the percentage of iron content of the ferritin present in the liver. In the next study, the livers of the experimental animals were partitioned and zinc analyses made on the liver fractions. Livers from animals receiving zinc showed that fraction III, the ferritin-containing fraction, was highest in zinc. Iron-induced ferritin synthesis studies showed that ferritin synthesis was not impaired by high dietary zinc. The hypothesis formulated from these studies was that zinc interferes with iron incorporation and release from ferritin.

Studies were conducted to determine whether both mercury and silver were antagonistic to copper in the nutrition of the chick. Although there was a statistical interaction between mercury and copper, it was not one of antagonism. Mercury did not reduce growth or increase mortality of copper-deficient chicks, but had both these effects when the diet was supplemented with copper. Silver was antagonistic to copper in that all the symptoms of copper deficiency were accentuated in the presence of silver and absence of copper. In the presence of copper, silver had no effect. These effects are explained on the basis of the similarities between the Ag++ion and the Cu++ion and the dissimilarities between the Hg++ion and either Cu+or Cu++ions.

The determination of the digestibility of the components of the cellulosic micelle has shown that the α-cellulose and pentosan constituents are digested unequally, with the micellular pentosans of alfalfa being less digestible than the alfalfa α-cellulose and the reverse situation being true with fescue; hence the micelle can not be considered a nutritive entity in these two forages. Thus the greater characterization of the carbohydrate fraction by micelle isolation may not be warranted. The digestibility of the total pentosans, accounting for 16.68 and 10.77% of the dry matter in fescue and alfalfa, respectively, when compared with the digestibility of the α-cellulose within species, was not different, suggesting that the combination of these two could result in a biologically meaningful partitioning of forages.

At birth, piglets had less immunoelectrophoretically identifiable serum proteins than the adult sow. Neonatal pig serum was different also in that it contained a serum protein not detectable in serum from a mature pig. The appearance and disappearance of serum proteins from birth to maturity occurred at fairly predictable times regardless of diet.

Estimates of the life span of the erythrocytes of three sheep were made using methylene-labeled C14glycine. The results obtained showed life spans of 131, 157, and 150 days which exceeded by approximately threefold previous estimates in which indirect techniques were used. The effect of the magnitude of erythrocyte life span on iron metabolism studies involving estimation of “physiological iron requirement” for maintenance is discussed.

The tallow from sheep fed purified diets contained less stearate and more oleate than tallow from either sheep fed haygrain diets or grazing animals. In some instances, the altered fatty acid distribution was sufficient to result in a tallow that was a liquid at room temperature. It is probable that less hydrogenation of unsaturated fatty acids was carried out by the rumen microorganisms of the sheep fed the purified diet, because the stearate level of the lipid of the rumen contents was appreciably less than that of the hayfed animals. A high content of transacids in the dietary fat resulted in high levels of transacids in the sheep tallow irrespective of the remainder of the diet, indicating the resistance of the transisomers to hydrogenation by the rumen flora.

The in vivoand in vitroincorporation of C14-labeled bicarbonate and acetate-2-C14into the ruminal volatile fatty acids of sheep receiving purified diets was studied. In the bicarbonate-CO2studies, most of the incorporated label was found in propionate and the specific activity of valerate exceeded that of either acetate or butyrate in all cases. A difference in incorporation rates between the sheep receiving diet 1 (Na plus K) and the sheep fed diet 1 was suggested and the addition of sodium and potassium bicarbonates to the diet enhanced C14O2incorporation into the fatty acids in the in vitrostudies. A product-precursor type relationship between acetate and butyrate was encountered in the in vivoexperiments and this relationship received additional support from the fatty acid analyses. Here again, the presence of the supplementary sodiumand potassium bicarbonates enhanced the incorporation of C14. Volatile fatty acid analyses revealed relatively higher levels of propionate in the rumen fluid of the sheep receiving diet 1 (Na plus K) than observed in rumen fluid from the sheep fed diet 1.

When genistin was fed at levels of 9, 18, 36 and 72 mg per day per mouse, the following results were obtained:1.An inverse linear relationship was found between the logarithm of dose levels of genistin and growth rate.2.Genistin appeared to have a depressing effect on testes weight beyond that attributable to differences in body weight.3.No spermatozoa were present in testes of the mice given the two higher levels of genistin.