Search PubMed⌕ Search

Biomedical subjects

L G Young

Publications and source records attributed to L G Young.

At least 55 records · Page 3Linked to original sources
PubMed1985

The effects of vomitoxin and feed intake on the performance and blood characteristics of young pigs.

Thirty barrows (average weight 8.4 kg) were used in a 3-wk experiment to determine the effects of the ingestion of vomitoxin (deoxynivalenol)-contaminated feed on performance and blood chemistry. The barrows were assigned randomly to consume either: 1) a control diet (C), fed ad libitum, 2) a vomitoxin contaminated diet (V; 10.5 ppm), fed ad libitum, or 3) a vomitoxin contaminated pair-fed at levels equal to those consumed by V animals (PF). The V and PF pigs had similar daily gains (.19 vs .20 kg) and feed intakes (.40 and .39 kg), but both of these were lower (P less than .01) than those for the C-fed pigs (.38 kg daily gain and .72 kg feed intake). The V-fed pigs had lower (P less than .05) hematocrit, hemoglobin, serum glucose and serum phosphorus and tended to have lower serum calcium (P less than .06) than C-fed pigs. The V-fed pigs had higher (P less than .05) hemoglobin and tended to have higher (P less than .08) serum phosphorus and lower (P less than .07) serum calcium than PF animals. There was a high total- and free-bilirubin concentration in serum of C- and V-fed pigs in the last sampling period (3-wk), which may be due to fasting and not cholestasis. No differences among treatments were observed in any of the other blood parameters. These results suggest that the differences in animal performance and blood parameters observed between control-and vomitoxin-fed pigs are mainly due to differences in feed intake.

Animal Feed↗
PubMed1984

Alteration in surface charge of chimpanzee sperm during epididymal transit and at ejaculation.

To further investigate changes in the sperm surface occurring during epididymal transit and after ejaculation, the surface negative charge on the head of chimpanzee sperm recovered from the caput (n = 4) and cauda epididymis (n = 3) and from the ejaculate (n = 4) was measured. Washed sperm were exposed to colloidal iron at pH 1.6, washed, mounted on carbon plates, and examined in a scanning electron microscope equipped with an energy dispersive X-ray analyzer. This technique permits evaluation of individual sperm in a population and provides information not available when the entire population is measured as a whole. The results demonstrate a net increase in negative charge during epididymal transit and after ejaculation and a change in charge distribution within the population from a unimodal to a tetra modal distribution. Caput sperm showed a unimodal distribution with a mode of 20 +/- 2%. Cauda sperm showed three modes at 23 +/- 1, 34 +/- 3, and 41 +/- 3%. Ejaculated sperm showed four modes at 21 +/- 3, 31 +/- 4, and 40 +/- 2, and 46 +/- 2%. The sperm population in the chimpanzee epididymis and ejaculate is not homogeneous, and this technique will aid in future measurement of fertility of subpopulations of sperm in the ejaculate.

Animals↗
PubMed1983

Studies on the flagellar ATPase of bull spermatozoa: extraction and characterization.

Adenosine triphosphatase (ATPase) activity of flagella isolated from ejaculated bull sperm was solubilized by 5 min exposure to 0.6 M KCl at 4 degrees C. ATPase activity in the flagellar extract was characterized with respect to enzyme, substrate, activator ion, salt, and hydrogen ion concentration. Flagellar extract required the presence of a divalent cation for activity: Mg2+, Ca2+, or Mn2+ could function as activator, but Zn2+ or Cd2+ could not. Magnesium-activated ATPase was maximal in the presence of Mg2+ and ATP in equimolar concentrations and at alkaline pH. Calcium activated ATPase was maximal over a wide range of Ca2+:ATP ratios and at pH 8.0. The presence of increasing concentrations of Na+ and/or K+ ions in the assay medium (0.5-300 mM) had no effect on the ATPase activity of flagellar extract.

Adenosine Triphosphatases↗
PubMed1983

Vomitoxin in corn fed to young pigs.

Four trials were conducted with young pigs to evaluate the effect of dietary level of vomitoxin-contaminated corn on performance and pathology. A dietary level of approximately 20 ppm vomitoxin caused vomiting, 12 ppm vomitoxin caused almost complete feed refusal and 1.3 ppm caused a significant depression in feed intake and rate Of gain. No lesions attributable to vomitoxin were observed in pigs fed up to 43 ppm dietary vomitoxin for a 21-d period. Alterations in various blood serum characteristics were observed in pigs fed vomitoxin, however, the effects could not be separated from those that may result from low intake of food.

Animals↗
PubMed1983

Effects of in vitro storage on the ATP-phosphohydrolase activity and ultrastructure of ejaculated bull sperm.

Extended bull ejaculates were stored in vitro at 4 +/- 1 degree C in the dark. The pH of the ejaculates did not change significantly during storage. The percentage of sperm with intact plasmalemmae was 70% on day 2 and negligible by day 36. On day 2, acrosomes were absent in 3% of the sperm and partial in about 20%; acrosomal damage increased with storage, and by day 36 acrosomes were absent in 12% of the sperm and partially degraded in 72%. The Mg++-ATPase activity decreased from 2.6 to 1.9 microM Pi liberated per 2 X 10(7) sperm per 30 min incubation at 37 degrees between days 2 and 9, but remained at about 65% of its initial value between days 9 and 36. Thin-sectioned sperm sampled from ejaculates at days 2, 9, and 36 of storage showed a gradual but steady deterioration, which began and was most drastic in the head. Flagellar deterioration was negligible on day 9, but by day 36 subtle evidence of deterioration appeared. The persistence of Mg++-ATPase at 65% of initial levels in sperm stored 36 days in vitro is probably attributable to the stability of the movement-related flagellar ATPases.

Adenosine Triphosphatases↗
PubMed1982

Moldy corn in diets of gestating and lactating swine.

Moldy corn was substituted for normal corn in four dietary treatments to provide 0, 2.1, 3.7 and 4.8 ppm of zearalenone. The diets were fed to gilts from the day after first observed estrus through two gestation-lactation periods. Each diets was fed to 11 gifts initially. Overall reproductive performance appeared to decrease as the level of moldly corn in the diet increased, with fewer sows completing two parities and fewer piglets weaned per litter, especially from sows fed the highest level of moldy corn. Three-week-old gilts that nursed sows fed the highest level of moldy corn had increased weight of reproductive tracts. In 35-d-old gilts, symptoms of estrogenism increased as the level of moldy corn in the diet increased, even though there were no symptoms of estrogenism in the mature gilts or sows fed the same diets. Neither zearalenone nor its metabolites (alpha- and beta-zearalenol) were detected in milk obtained 1 or 14 d postpartum.

Animal Feed↗
PubMed1982

Surface components of ejaculated chimpanzee sperm.

Surface components of ejaculated chimpanzee sperm were radiolabeled by enzymatic iodination with lactoperoxidase and Na125I. The sperm were lysed and the labeled components analyzed on SDS-7.5% polyacrylamide gels. Electrophoresis of solubilized radioactivity resolved four components with approximate molecular weights of 72,000, 49,000, 25,000 and 17,000 daltons. To identify components, which might be adsorbed to the chimpanzee sperm surface from seminal secretions, seminal plasma was labeled. Electrophoresis of labeled seminal plasma resolved three components with approximate molecular weights of 63,000, 26,000, and 17,000 daltons, two of which comigrated with a labeled sperm surface component.

Animals↗
PubMed1982

High tolerance of broilers to vomitoxin from corn infected with Fusarium graminearum.

Corn purposely infected with Fusarium graminearum was found to contain 800 to 900 mg vomitoxin/kg. Contaminated corn was substituted for control corn at 0, 6, 12, 18, and 24% in a corn-soybean meal ration. Broiler cockerels were given each experimental diet from 6 to 11 days of age; then sample groups were necropsied. Remaining birds were subsequently offered commercial starter for 2 days and sample groups again necropsied. Growth and diet consumption were not significantly reduced until contaminated corn exceeded 12% of the ration (116 mg vomitoxin/kg). Alertness, coordination, and feathering appeared normal regardless of treatment. Birds that received contaminated corn exhibited plaques in the mouth and gizzard erosions proportional to the level of substitution. All lesions were generally restricted to the epithelial layer and no liver or kidney involvement could be demonstrated. A short return to uncontaminated feed eliminated most lesions. Fowl appear to be considerably more tolerant of vomitoxin than swine.

Animals↗
PubMed1981

Immunological identification of lactoferrin as a shared antigen on radioiodinated human sperm surface and in radioiodinated human seminal plasma.

After lactoperoxidase-catalyzed iodination of either human sperm surface or human seminal plasma, a 72-76 kdalton component was resolved on SDS-7.5% polyacrylamide gels. The approximate molecular weight of this component was consistent with that of human lactoferrin, a major sperm-coating antigen. Immunoprecipitation of labeled sperm surface and of labeled seminal plasma with specific anti-human lactoferrin antibody identified lactoferrin as a constituent of this 72-76 kdalton component both on human sperm surface and in human seminal plasma. These data show that components which have been inferred to be shared because of similarities in biochemical characteristics also contain immunologically identical components.

Absorption↗
PubMed1981

Wheat shorts in diets of gestating swine.

Sixty-four gilts were assigned to be bred at first or third observed estrus and fed gestation diets of pelleted wheat shorts with a free choice mineral-vitamin supplement or fortified corn-soybean meal. Only the dietary effects are included in this report. The gilts were fed their respective diets starting at 25 days after insemination. The experiment continued through three gestation-lactation cycles. Females fed the wheat shorts received less digestible energy during gestation and weighed less at day 109 of gestation and days 1, 7 and 21 of lactation in each of the three gestation-lactation periods. Females fed wheat shorts had lighter pigs at birth, weaned more pigs per litter in each parity and returned to estrus more slowly after weaning than females fed a corn-soybean meal diet. Results of a metabolism trial conducted with 12 barrows revealed that wheat shorts contained approximately 2.93 kcal digestible energy/kg dry matter and had an apparent protein digestibility of 72%, compared with values of 4.0 kcal and 86%, respectively, for the corn-soybean meal diets.

Animal Feed↗
PubMed1981

Reproductive performance of gilts bred on first versus third estrus.

Reproductive performance of gilts initially bred on first observed estrus was compared with that of gilts bred on third observed estrus. One-hundred and twelve Yorkshire gilts were used and 106 conceived. Conception rate to initial breeding was lower among gilts bred on first versus third observed estrus (69.6 vs 77.4%). Estrus was observed in some gilts between 140 and 149 days of age; the mean age at estrus for all gilts that were bred was 177.8 days. The mean weight at puberty was 91.7 kilograms. There was a tendency toward increased litter size at birth and weaning when breeding was delayed to third estrus, but the difference was not statistically significant. Live weight of piglets was increased in litters from sows bred initially on third estrus. The weaning-to-estrus or conception interval was not influenced by initial breeding on first or third estrus. Maintaining gilts until third observed estrus required feed and accommodation for approximately 44 additional days before breeding and resulted in 1.4 additional pigs per sow over three parities.

Animals↗
PubMed1981

Response of cows to a reduction in dietary crude protein from 17% to 13% during early lactation.

Four treatments involving 48 multiparous cows (12 per group) were compared during wk 0 to 19 postpartum. Treatments involved decreasing dietary crude protein from 17% to 13% at the 5th, 10th, or 15th wk postpartum or leaving on the 17% diet throughout. Treatment means across periods for milk yields, solids-corrected-milk, dry matter intake, crude protein intake, and milk fatty acids of chain length less than or equal to palmitoleic acid, adjusted by covariance, in orders listed were 27.4, 28.0, 29.1, 29.5 kg; 23.2, 25.1 26.4, 26.8 kg; 19.0, 19.7, 20.4, 20.6 kg; 2.65, 2.98, 3.31, 3.44 kg; 59.83, 63.72, 62.74, 64.55%. There were linear increased as duration on 17% diet increased. The effect of decreasing dietary protein percent was greatest for the change at 5 wk postpartum. Milk fat, protein, and lactose percentages were not affected by treatment. Protein disappearance from nylon bags inserted in rumen fistulated steers was more rapid on 17% than 13% crude protein rations, but ration dry matter disappearance did not differ between rations.

Animal Feed↗
PubMed1978

Avian encephalomalacia in Barbados, West Indies: a description of spontaneous field cases with feed analyses.

The clinical, necropsy and histopathological findings in four natural outbreaks of encephalomalacia are reported. Feed analyses implicated low levels of vitamin E as the probable cause of the condition. Treatment with vitamin E has proved to be very effective. The instability of vitamin E in animal feed ingredients during long periods of shipment into the Caribbean may be important in the pathogenesis of the disease.

Animal Feed↗