A double-spike MC TIMS measurement procedure for low-amount Ca isotopic analysis of limited biological tissue samples.

The application of Ca isotopic analysis in biomedical studies has great potential to identify changes in Ca metabolism and bone metabolism. Reliable measurement of Ca isotope-amount ratios is challenging considering limited Ca amounts and significant procedural blank levels. In this study, Ca purification was performed using the DGA Resin, optimized for low procedural blanks and separation of Ca from matrix elements and isobaric interferences (Na, Mg, K, Ti, Fe, Ba), while maintaining quasi-quantitative recoveries which are sufficient since a 42Ca-48Ca double-spike (DS) was applied. Ca isotopic analysis was performed using multicollector thermal ionization mass spectrometry (MC TIMS). The obtained procedural Ca blank of ≤10 ng enables processing of limited Ca amounts down to 670 ng. Data reduction of the measured Ca isotope-amount ratios was performed using an in-house developed software solving the DS algorithm. Data quality was improved by extension of equilibration time of the sample-DS mixture and implementation of a normalization strategy for raw isotopic data. The reported δ(44Ca/40Ca)NIST SRM 915a of NIST SRM 915a processed as a sample was found to be 0.01 ‰ ± 0.08 ‰ (2 SD, n = 15). Ca isotope-amount ratios of the reference material NIST SRM 1400 (bone ash), NIST SRM 1486 (bone meal), GBW07601 (human hair), and IAPSO (seawater) were in good agreement within uncertainty with literature data. Novel data on additional reference materials for biological tissues (hair) is presented, which might indicate a potential fractionation of Ca incorporated into hair tissue when compared to the blood pool.

Acromelic frontonasal dysostosis and ZSWIM6 mutation: phenotypic spectrum and mosaicism.

Acromelic frontonasal dysostosis (AFND) is a distinctive and rare frontonasal malformation that presents in combination with brain and limb abnormalities. A single recurrent heterozygous missense substitution in ZSWIM6, encoding a protein of unknown function, was previously shown to underlie this disorder in four unrelated cases. Here we describe four additional individuals from three families, comprising two sporadic subjects (one of whom had no limb malformation) and a mildly affected female with a severely affected son. In the latter family we demonstrate parental mosaicism through deep sequencing of DNA isolated from a variety of tissues, which each contain different levels of mutation. This has important implications for genetic counselling.

SunSmart: evaluation of a pilot school-based sun protection intervention in Hispanic early adolescents.

The incidence of melanoma is rising among Hispanic populations in the United States. The purpose of this study is to evaluate the impact of a pilot sun safety educational intervention conducted from 2006 to 2012 on Hispanic early adolescents in a high ultraviolet environment. Nineteen schools with high Hispanic enrollment were recruited from urban neighborhoods in Los Angeles. The analytic sample was restricted to students identifying as Hispanic or Latino (n = 777). A mixed effects linear model was used to test mean changes from pre- to posttest on students' sun protection knowledge, attitudes and behaviors. Significant improvements were observed across several cognitive outcomes related to sun protection, including knowledge of and attitudes toward sun protection and self-efficacy to wear sunscreen. However, changes in sun protective behaviors were not achieved. Although some improvements were observed, future studies should identify the factors that motivate sun protection in this population and develop tailored prevention strategies, as improving the sun safe behaviors of Hispanic youths may aid in reducing the risk of melanoma in adulthood in this population.

Effect of Megasphaera elsdenii NCIMB 41125 dosing on rumen development, volatile fatty acid production and blood ß-hydroxybutyrate in neonatal dairy calves.

Thirty calves were randomly assigned to two treatments and fed until weaning [42 days (d) of age]. Treatments were a control group (n = 15), which did not receive Megasphaera elsdenii (Me0) and a M. elsdenii group, which received a 50-ml oral dose of M. elsdenii NCIMB 41125 (10(8) CFU/ml) at day 14 day of age (Me14). Calves were given colostrum for the first 3 day followed by limited whole milk feeding. A commercial calf starter was offered ad libitum starting at day 4 until the end of the study. Fresh water was available throughout the study. Feed intake and growth were measured. Blood samples were collected via jugular venipuncture to determine ß-hydroxybutyrate (BHBA) concentrations. Fourteen male calves (seven per group) were euthanised on day 42 and digestive tracts harvested. Reticulo-rumen weight was determined and rumen tissue samples collected from the cranial and caudal sacs of the ventral and dorsal portions of the rumen for measurements of papillae length, papillae width and rumen wall thickness. Dosing with M. elsdenii NCIMB 41125 improved starter dry matter intake (DMI), weaning body weight (BW) and tended to improve average daily gain. Calves in Me14 group had greater plasma BHBA concentration than Me0-calves during the last 3 weeks of the trial and had at day 42 greater reticulo-rumen weight, papillae width and papillae density compared to Me0. No differences in rumen wall thickness or papillae length were observed between the two groups. Total volatile fatty acids, acetate and propionate production did not differ between treatments, but butyrate production was greater in Me14 than Me0. Dosing M. elsdenii NCIMB 41125 showed benefit for calves with improved feed intake and rumen development suggesting increased epithelium metabolism and improved absorption of digestive end products.

Effect of castration method on neurohormonal and electroencephalographic stress indicators in Holstein calves of different ages.

As public concern for food animal welfare increases, a need to validate objective pain assessment tools exists in order to formulate animal welfare policies and facilitate regulatory approval of compounds to alleviate pain in livestock in the United States. The aims of this study were (1) to compare the physiological response to pain induced by surgical and nonsurgical (band) castration in calves and (2) to elucidate age-related differences in pain response of calves subjected to different castration methods. Seventy-six Holstein bull calves were blocked by age (≤8-wk and ≥6-mo-old) and randomly assigned to 1 of 4 treatment groups: control (n=20), castration by banding (n=18), cut-and-clamp surgical castration (n=20), and cut-and-pull surgical castration (n=18). Measurements included electroencephalogram, heart rate variability, infrared thermography, electrodermal activity, and concentrations of serum cortisol and plasma substance P before, during, and within 20min following castration. Electroencephalogram recordings showed desynchronization for all treatments, consistent with increased arousal; yet the magnitude of desynchronization was greatest for 6-mo-old calves castrated by cut-and-clamp. Additionally, older calves in the cut-and-pull group showed greater desynchronization than younger calves in the same group. Based on the heart rate variability analysis, 6-mo-old calves in the control or cut-and-pull castration groups showed greater sympathetic tone than younger calves in the same treatment groups. Overall, younger calves showed lower electrodermal activity than older calves. Regardless of treatment, concentrations of cortisol and plasma substance P were greater in 6-mo-old calves relative to their younger counterparts, indicating a more robust response to all treatments in older calves. In summary, neurohormonal and electroencephalographic stress responses of calves to castration were age-specific. Castration by cut-and-clamp showed the most pronounced stress response in 6-mo-old calves. These findings provide evidence that support welfare policies recommending castration at an early age and the use of analgesic compounds at the time of surgical castration especially in older calves. However, the potential long-term negative consequences of early untreated pain must be considered and warrant further investigation.

Neomorphic agouti mutations in obese yellow mice.

Several dominant mutations of the mouse agouti coat colour gene have pleiotropic effects that include obesity and a yellow coat. The Ay allele is caused by a large deletion that affects the expression of several contiguous genes. We show that three other obesity-associated agouti mutations, Aiy, Asy and Avy, are due to different molecular alterations that result in ubiquitous expression of a chimaeric RNA that encodes a normal agouti protein. The Aiy and Avy alleles are caused by insertion of an intracisternal A particle element 1 kb or 100 kb, respectively, upstream of agouti coding sequences. These results provide a model for other genes that show allele-specific imprinting, and demonstrate that molecular mechanisms typically responsible for activation of proto-oncogenes can also lead to other disease phenotypes.

Sleep loss and change detection in simulated driving.

Driver sleepiness is a leading contributor to road crashes. Sleep-related crashes are more likely to involve collision with a stationary object than non-sleep-related crashes. The mechanism underpinning this is unknown; one potential explanation may be an increased propensity for change blindness. Twenty-four drivers with at least one year of independent driving experience completed two simulated drives: one following a normal night of sleep (7-8 h) and one following sleep restriction (5 h). The drive consisted of 5 laps of an 11.3 km circuit, taking approximately 45 min. Each lap comprised half urban and half rural driving environments. Twenty times during the drive the visual screen was blanked for 500 ms, and when it reappeared participants were asked whether there were any changes. Twelve times a change occurred, and eight times no change occurred. Additionally, four unexpected changes occurred; for example, the language of the road signs was changed from English to German. At the end of each drive, participants were asked if anything unusual occurred. Sleep loss resulted in significantly increased subjective sleepiness and subjective workload. Driving in an urban environment did not increase alertness; subjective sleepiness ratings did not significantly differ between urban and rural environments. Change detection accuracy for both cued and unexpected changes was not significantly affected by sleep loss. In line with previous research, accuracy was greater for changes with high safety relevance and those occurring in rural environments. Collectively the findings of the study suggest that increase change blindness is probably not a contributor to sleep-related road crashes; however, future on-road research and with greater levels of sleep loss is needed to confirm findings.

How do reproductive skew and founder group size affect genetic diversity in reintroduced populations?

Reduced genetic diversity can result in short-term decreases in fitness and reduced adaptive potential, which may lead to an increased extinction risk. Therefore, maintaining genetic variation is important for the short- and long-term success of reintroduced populations. Here, we evaluate how founder group size and variance in male reproductive success influence the long-term maintenance of genetic diversity after reintroduction. We used microsatellite data to quantify the loss of heterozygosity and allelic diversity in the founder groups from three reintroductions of tuatara (Sphenodon), the sole living representatives of the reptilian order Rhynchocephalia. We then estimated the maintenance of genetic diversity over 400 years (approximately 10 generations) using population viability analyses. Reproduction of tuatara is highly skewed, with as few as 30% of males mating across years. Predicted losses of heterozygosity over 10 generations were low (1-14%), and populations founded with more animals retained a greater proportion of the heterozygosity and allelic diversity of their source populations and founder groups. Greater male reproductive skew led to greater predicted losses of genetic diversity over 10 generations, but only accelerated the loss of genetic diversity at small population size (<250 animals). A reduction in reproductive skew at low density may facilitate the maintenance of genetic diversity in small reintroduced populations. If reproductive skew is high and density-independent, larger founder groups could be released to achieve genetic goals for management.

Eelgrass meadows in the California Channel Islands and adjacent coast reveal a mosaic of two species, evidence for introgression and variable clonality.

BACKGROUND AND AIMS: Seagrasses are important facilitator species in shallow, soft-bottom marine environments worldwide and, in many places, are threatened by coastal development and eutrophication. One narrow-leaved species (Zostera marina) and one wide-leaved species, variously designated as Z. marina, Z. pacifica or Z. asiatica, are found off the California Channel Islands and adjacent California-Mexico coast. The aim of the present study was to confirm species identification genetically and to link patterns of genetic diversity, connectivity and hybridization among and within the populations with historical sea levels (Ice Age) or the contemporary environment. METHODS: Samples (n = 11-100) were collected from 28 sites off five California Channel Islands and six sites off the adjacent coast of southern California and Baja California, Mexico. DNA polymorphisms of the rDNA-ITS (internal transcribed spacer) cistron (nuclear), the matK intron (chloroplast) and nine microsatellite loci (nuclear) were examined in a population genetic and phylogeographic context. KEY RESULTS: All wide-leaved individuals were Z. pacifica, whereas narrow-leaved forms were Z. marina. Microsatellite genotypes were consistent with hybridization between the two species in three populations. The present distribution of Z. pacifica follows a glacial age land mass rather than present oceanographic regimes, but no link was observed between the present distribution of Z. marina and past or present environments. Island populations of Z. marina often were clonal and characterized by low genotypic diversity compared with populations along the Baja California coast. The high level of clonal connectivity around Santa Catalina Island indicated the importance of dispersal and subsequent re-establishment of vegetative fragments. CONCLUSIONS: The pristine environmental conditions of offshore islands do not guarantee maximum genetic diversity. Future restoration and transplantation efforts of seagrasses must recognize cryptic species and consider the degree of both genetic and genotypic variation in candidate donor populations.

Conflicts and contradictions in current skin cancer screening guidelines.

PURPOSE OF REVIEW: To review skin cancer screening guidelines from major public health/medical organizations. RECENT FINDINGS: No consensus exists on whether or not screening to prevent skin cancer is warranted. SUMMARY: The best evidence of screening efficacy should come from population-based randomized trials, but is unlikely to exist due to feasibility constraints. Consequently, consensus should be built from observational/non-randomized designs, such as the SCREEN study in Germany. Current guidelines often focus on melanoma alone, while potential benefits of screening for non-melanoma skin cancers (NMSC) are largely overlooked. There may be less room for doubt regarding the value of screening, if both diseases were considered. Further, targeted approaches, i.e. screening only in high-risk populations, remain poorly defined and untested. Continuing to state that there is insufficient evidence to recommend screening leads to confusion about whether or not to screen, and is unlikely to result in substantial changes to the morbidity of NMSC and significant mortality from melanoma.

Interaction between supplemental zinc oxide and zilpaterol hydrochloride on growth performance, carcass traits, and blood metabolites in feedlot steers.

Interactive effects of supplemental Zn and zilpaterol hydrochloride (ZH) were evaluated in feedlot steers ( = 40; 652 kg ± 14 initial BW) to determine their impact on feedlot performance, blood constituents, and carcass traits. The study was conducted as a randomized complete block design with a 2 × 2 factorial treatment arrangement. Steers were blocked by BW and randomly assigned to treatments. Factors consisted of supplemental Zn (60 or 300 mg/kg diet DM) and ZH (0 or 8.33 mg/kg) in the diets. For diets supplemented with 300 mg Zn/kg DM, 60 mg Zn/kg was supplemented as zinc sulfate and 240 mg Zn/kg was supplemented as zinc oxide, and the diet was fed for 24 d. Zilpaterol hydrochloride was fed for 21 d followed by a 3-d withdrawal. Cattle were housed in partially covered individual feeding pens equipped with automatic waterers and fence-line feed bunks and were fed once daily for ad libitum intake. Plasma samples were collected on d 0 and 21 to assess changes in Zn, plasma urea nitrogen (PUN), glucose, and lactate concentrations, and serum samples were collected on d 21 to assess IGF-1 concentration. On d 25, cattle were weighed and transported 450 km to a commercial abattoir for harvest; HCW and incidence of liver abscesses were recorded. Carcass data were collected after 36 h of refrigeration. Data were analyzed as a mixed model with Zn, ZH, and Zn × ZH as fixed effects; block as a random effect; and steer as the experimental unit. No interaction or effects of Zn or ZH were observed for IGF-1 concentration, plasma glucose, or lactate concentrations ( ≥ 0.25). No interaction between Zn and ZH was observed for PUN concentration, but PUN decreased with ZH ( < 0.01). There were no effects of ZH or Zn on ADG, DMI, final BW, feed efficiency, HCW, back fat, KPH, quality grade, or incidence of liver abscesses ( > 0.05). Zinc supplementation tended ( = 0.08) to improve the proportion of carcasses grading USDA Choice. Feeding ZH decreased yield grade ( = 0.05) and tended to increase LM area ( = 0.07). In conclusion, increasing dietary concentrations of Zn does not impact response to ZH, but feeding ZH altered circulating concentrations of PUN.

Finding Prospective Mates by the Parasitoid Wasp Urolepis rufipes (Hymenoptera: Pteromalidae).

Cues from emergence sites may be predictive of mating opportunities if potential mates are slow to disperse after emergence, and particularly if emergence sites are clumped, as in the solitary parasitoid wasp Urolepis rufipes Ashmead. Males emerge before females, and the present study suggests that males may use emergence sites of conspecific males to locate mates. In choice experiments, virgin males spent more time on a male-emerged host (a host from which a male had recently emerged) than on a female-emerged host. Relative to when no host was present, virgin males also marked more in the presence of a male-emerged host, but did not mark more in the presence of a female-emerged host. Females, but not other males, are known to be attracted to male marks. Unlike for males, there was no evidence that females distinguished between male-emerged and female-emerged hosts. Virgin females preferred areas where multiple males had marked over areas where a single male had marked. Such areas had more total marks, yet marks per male did not differ between aggregated and solitary males. Thus, through his own attraction to male-emerged hosts and by marking near other males a male may find and attract females, and with no apparent increase in the cost of attraction.

Effects of crystalline menthol on blood metabolites in Holstein steers and in vitro volatile fatty acid and gas production.

Fifty-two Holstein steers (573 ± 9.92 kg BW) were used to determine if oral administration of crystalline menthol would induce changes in endogenous secretions of IGF-1 and circulating concentrations of glucose, lactate, and plasma urea nitrogen (PUN). Steers were blocked by BW and assigned within block to treatment. Treatments consisted of 0, 0.003, 0.03, or 0.3% crystalline menthol (DM basis) added to the diet. Animals were housed in individual, partially covered pens equipped with feed bunks and automatic water fountains. On d 1 of the experiment, blood samples were obtained via jugular venipuncture at 0, 6, 12, 18, and 24 h after feeding. Treatment administration commenced on d 2, and blood samples were again drawn at 0, 6, 12, 18, and 24 h after feeding. This blood-sampling schedule was repeated on d 9, 16, 23, and 30. Plasma was analyzed for PUN, glucose, and lactate concentrations. Serum was used to analyze IGF-1 concentration. Body weights were measured on d 1, 9, 16, 23, and 30. To accompany the live animal phase, in vitro fermentations were performed using ruminal fluid cultures. Measurements included VFA concentrations and fermentative gas production for cultures containing crystalline menthol at 0, 0.003, 0.03, or 0.3% of substrate DM. Addition of menthol to the diet of steers resulted in a treatment × day interaction ( < 0.01) for concentrations of IGF-1, PUN, and plasma glucose. Cattle fed 0 and 0.003% menthol had greater serum IGF-1 concentrations on d 2 compared with steers fed 0.03% menthol. Steers fed 0% menthol had greater serum IGF-1 concentrations on d 9 compared with steers fed 0.03 and 0.3% menthol, whereas no differences were observed on d 23 or 30. Plasma glucose was similar among treatments until d 23, when steers supplemented with 0.03% menthol had lower glucose concentrations. Plasma urea nitrogen concentrations were not different among treatments; however, PUN concentrations varied by day. A linear response was detected for BW ( = 0.03), with steers consuming 0% menthol having the greatest BW and steers that consumed 0.3% menthol having the lightest BW until d 30. A menthol × day interaction was observed for daily feed deliveries ( < 0.01): cattle fed 0.3% menthol consumed less feed from d 5 through 12. Furthermore, in vitro gas production and VFA concentrations were unaffected by addition of menthol ( > 0.21). In conclusion, menthol supplementation minimally affected blood parameters associated with growth or ruminal fermentative activity.

Kinetics of the processing of the precursor to 4.5 S RNA, a naturally occurring substrate for RNase P from Escherichia coli.

A study was made of the cleavage by M1 RNA and RNase P of a non-tRNA precursor that can serve as a substrate for RNase P from Escherichia coli, namely, the precursor to 4.5 S RNA (p4.5S). The overall efficiency of cleavage of p4.5S by RNase P is similar to that of wild-type tRNA precursors. However, unlike the reaction with wild-type tRNA precursors, the reaction catalyzed by the holoenzyme with p4.5S as substrate has a much lower Km value than that catalyzed by M1 RNA with the same substrate, indicating that the protein subunit plays a crucial role in the recognition of p4.5S. A model hairpin substrate, based on the sequence of p4.5S, is cleaved with greater efficiency than the parent molecule. The 3'-terminal CCC sequence of p4.5 S may be as important for cleavage of this substrate as the 3'-terminal CCA sequence is for cleavage of tRNA precursors.

Genetic studies of the mouse mutations mahogany and mahoganoid.

The mouse mutations mahogany (mg) and mahoganoid (md) are negative modifiers of the Agouti coat color gene, which encodes a paracrine signaling molecule that induces a swithc in melanin synthesis from eumelanin to pheomelanin. Animals mutant for md or mg synthesize very little or no pheomelanin depending on Agouti gene background. The Agouti protein is normally expressed in the skin and acts as an antagonist of the melanocyte receptor for alpha-MSH (Mc1r); however, ectopic expression of Agouti causes obesity, possibly by antagonizing melanocortin receptors expressed in the brain. To investigate where md and mg lie in a genetic pathway with regard to Agouti and Mc1r signaling, we determined the effects of these mutations in animals that carried either a loss-of-function Mc1r mutation (recessive yellow, Mc1re) or a gain-of-function Agouti mutation (lethal yellow, Ay). We found that the Mc1re mutation suppressed the effects of md and mg, but that md and mg suppressed the effects of Ay on both coat color and obesity. Plasma levels of alpha-MSH and of ACTH were unaffected by md or mg. These results suggest that md and mg interfere directly with Agouti signaling, possibly at the level of protein production or receptor regulation.

Total hip arthroplasty with cement and without acetabular bone graft for severe hip dysplasia. A concise follow-up, at a minimum of twenty years, of a previous report.

We previously evaluated a cohort of fifty-three patients with severe hip dysplasia (Crowe Type-II, III, or IV subluxation) who underwent a total of sixty-six Charnley total hip arthroplasties. The acetabular component was placed at the anatomic hip center, the superolateral defect was filled with cement, and no bone-grafting was used to supplement the acetabular wall. All but one patient, who was lost to follow-up, were followed until death or for a minimum of twenty years. Radiographic and functional follow-up data were collected prospectively. This retrospective review included twenty-four patients (thirty-four hips) who were alive at a minimum of twenty years following the surgery. Fourteen (22%) of the sixty-five hips underwent revision of a component, with eleven of the revisions performed because of aseptic loosening. Eight of those eleven hips underwent revision because of acetabular loosening alone; two, because of femoral loosening alone; and one, because of loosening of both components. The combined prevalence of revision because of aseptic loosening of the acetabular component and radiographic evidence of failure of the acetabular component was 28% (eighteen hips). With the numbers available, the need for acetabular revision was not associated with the percentage of cement coverage (p = 0.362) or the Crowe classification (p = 0.159). At a minimum of twenty years postoperatively, the survivorship of the acetabular component was 86% +/- 8% with revision because of aseptic loosening as the end point and 82% +/- 10% with revision because of aseptic loosening or radiographic evidence of loosening as the end point. The results that we evaluated at a minimum of twenty years after use of this technique can be compared with the results of other techniques in studies with similar long-term follow-up periods.

Manipulation of dietary calcium concentration to potentiate changes in tenderness of beef from heifers supplemented with zilpaterol hydrochloride.

Dietary Ca concentrations were manipulated during supplementation of zilpaterol hydrochloride (ZH) to evaluate impact on feedlot performance, carcass characteristics, and beef tenderness using 96 heifers (BW 392 kg ± 3.2). We hypothesized that temporary depletion followed by repletion of dietary Ca before harvest would increase intracellular Ca concentrations, thus stimulating postmortem activity of Ca-dependent proteases to effect changes in tenderness. Heifers were stratified by initial BW and randomly assigned, within strata (block), to treatments consisting of a finishing diet in which Ca was added in the form of limestone (+Ca) or removed (-Ca) during ZH supplementation. Cattle were fed a common diet, including limestone, before ZH supplementation, and 28 d before slaughter, ZH was added to the diet with and without supplemental Ca. Calcium content of the diets during ZH supplementation was 0.74% or 0.19% (diet DM) for +Ca and -Ca, respectively. Zilpaterol hydrochloride was fed for 25 d then removed from the diet 3 d before harvest. The final 3 d before harvest, all cattle were fed Ca at 0.74% of diet DM. Heifers were housed in concrete-surfaced pens with 8 animals/pen (6 pens/treatment). At the end of the finishing phase, animals were weighed and transported to an abattoir in Holcomb, KS. Severity of liver abscesses and HCW were collected the day of harvest, and after 48 h of refrigeration, USDA yield and quality grades, KPH, LM area, and 12th-rib subcutaneous fat thickness were determined. Boneless loin sections were also collected for Warner-Bratzler shear force determination. Removal of Ca did not affect Warner-Bratzler shear force values (P = 0.64). In addition, ADG, DMI, final BW, and feed efficiency were unaffected by treatment (P > 0.05). Carcass measurements also were unaffected by the temporary decrease in dietary Ca (P > 0.05). In conclusion, temporary depletion of dietary Ca during ZH supplementation did not alter beef tenderness, live animal performance, or carcass measurements.

Effects of flaxseed encapsulation on biohydrogenation of polyunsaturated fatty acids by ruminal microorganisms: feedlot performance, carcass quality, and tissue fatty acid composition.

The objective of this study was to evaluate the efficacy of protecting PUFA within ground flaxseed against ruminal biohydrogenation by encapsulating them in a matrix consisting of a 1:1 blend of ground flaxseed and dolomitic lime hydrate (L-Flaxseed). Crossbreed heifers ( = 462, 346 ± 19 kg) were blocked by weight and randomly assigned to pens. Pens were assigned to 1 of 6 dietary treatments in a randomized complete block design. Treatment 1 consisted of a combination of 54.6% steam-flaked corn (SFC), 30.0% wet corn gluten feed, 8.0% roughage, and supplement (0% flaxseed). In treatments 2 and 3, a proportion of SFC was replaced with 3 and 6% flaxseed, respectively; in treatments 4, 5, and 6, SFC was replaced with 2, 4, or 6% L-Flaxseed, respectively. Cattle were fed for 140 or 168 d and then harvested in a commercial abattoir where carcass data were collected. Approximately 24 h after harvest, carcasses were evaluated for 12th-rib fat thickness, KPH, LM area, marbling score, and USDA yield and quality grades. Samples of LM were also obtained for determination of long-chain fatty acid profiles. Cattle that were fed diets with 4 and 6% L-Flaxseed consumed less feed than other treatments ( < 0.05), which adversely affected ADG. Compared with cattle fed 0% flaxseed, cattle in these treatments had lower final BW (18 and 45 kg less for the 4 and 6% L-Flaxseed treatments, respectively), less ADG (0.16 and 0.48 kg/day less for the 4 and 6% L-Flaxseed treatments, respectively), and lower carcass weights, dressing percentages, LM areas, backfat thicknesses, and marbling scores ( < 0.05). The addition of flaxseed or 2% L-Flaxseed did not affect performance or carcass traits ( > 0.05). Supplementation with flaxseed increased ( < 0.05) the concentration of α-linolenic acid (ALA) in meat (0.173, 0.482, 0.743 mg/g for 0, 3, and 6% flaxseed, respectively). Furthermore, proportionate increases in the ALA content of muscle tissue were 47% greater when flaxseed was encapsulated within the dolomitic lime hydrate matrix (0.288, 0.433, 0.592 mg/g for 2, 4, and 6% L-Flaxseed, respectively). Both products showed a linear response in ALA concentration ( > 99%; increases for Flaxseed and L-Flaxseed of 0.095 and 0.140 mg of ALA/g of tissue for each percentage of flaxseed added). This study indicates that a matrix consisting of dolomitic lime hydrate is an effective barrier to ruminal biohydrogenation of PUFA; however, adverse effects on DMI limit the amounts that can be fed.

Protection of polyunsaturated fatty acids against ruminal biohydrogenation: Pilot experiments for three approaches.

Three methods for protection of PUFA against biohydrogenation by ruminal microorganisms were evaluated. In method 1 a blend of ground flaxseed, calcium oxide, and molasses was processed through a dry extruder. In method 2, a blend of ground flaxseed, soybean meal, molasses, and baker's yeast was moistened and prewarmed, allowing enzymes from yeast to produce reducing sugars, and the mixture was subsequently processed through a dry extruder like in method 1. In method 3, ground flaxseed was embedded within a matrix of dolomitic lime hydrate (L-Flaxseed) as a protective barrier against biohydrogenation. Dolomitic lime was mixed with ground flaxseed, water was added, the mixture was blended in a high-speed turbulizer, and the resulting material was then dried to form a granular matrix. Methods 1 and 2 were tested in 1 study (study 1), and method 3 was tested in 2 studies (studies 2 and 3). In study 1, 60 crossbred yearling steers (BW = 475 ± 55 kg) were used in a randomized complete block design experiment. Steers were fed for 12 d with a diet consisting of 48.73% steam-flaked corn, 35% wet corn gluten feed, 12% corn silage, and 4.27% vitamins and minerals (Control). For the other 4 treatments, a portion of wet corn gluten feed was replaced with 5% of unprocessed or extruded mixtures as described for methods 1 and 2. Steers were weighed, and jugular blood samples were taken for analysis of long-chain fatty acids (LCFA) on d 0 and 12 of the study. Both methods failed to improve resistance of PUFA against biohydrogenation (P > 0.1). In study 2, in situ fatty acid disappearance was evaluated for ground flaxseed (Flaxseed) or L-Flaxseed using 6 ruminally fistulated Holstein steers. The proportion of α-linolenic acid (ALA) that was resistant to ruminal biohydrogenation was approximately 2-fold greater for L-Flaxseed than for Flaxseed (P < 0.05). In study 3, 45 steers (269 ± 19.5 kg initial BW) were used in a randomized complete block design. Steers were fed diets containing 0% Flaxseed (No Flaxseed), and in treatments 2 and 3, a portion of flaked corn was replaced with Flaxseed or L-Flaxseed. Animals were weighed and blood samples were taken on d 0, 7, and 14 of the study, and LCFA were analyzed. The use of L-Flaxseed in study 3 increased plasma concentrations of ALA to more than 4 times the level observed in cattle fed unprotected flaxseed, suggesting the dolomitic lime hydrate was effective as a protective barrier against biohydrogenation.

Generation of neutral atomic beams utilizing photodetachment by high power diode laser stacks.

We demonstrate the use of high power diode laser stacks to photodetach fast hydrogen and carbon anions and produce ground term neutral atomic beams. We achieve photodetachment efficiencies of ∼7.4% for H(-) at a beam energy of 10 keV and ∼3.7% for C(-) at 28 keV. The diode laser systems used here operate at 975 nm and 808 nm, respectively, and provide high continuous power levels of up to 2 kW, without the need of additional enhancements like optical cavities. The alignment of the beams is straightforward and operation at constant power levels is very stable, while maintenance is minimal. We present a dedicated photodetachment setup that is suitable to efficiently neutralize the majority of stable negative ions in the periodic table.