Effect of ascorbic acid on the disease caused by Escherichia coli challenge infection

In a series of experiments, leghorn-type chickens were fed diets containing from 0 to 880 mg of ascorbic acid/kg of feed beginning 1 day before air-sac challenge with Escherichia coli. Infection occurred in 46/60 (76%) of the controls and in 12/63 (19%) of those given feed containing 330 mg of ascorbic acid/kg. Levels of ascorbic acid above and below 330 mg/kg feed were less effective.     

Adrenal cortex reactivity in dairy cows differs between lactational stages and between different feeding levels

Changes in ACTH challenge test characteristics in dairy cows changing their physiological status at different lactational stages and different feeding levels were not investigated in terms of repeatability yet. In 23 multiparous Holstein cows (10 cows fed a sole fresh herbage diet without concentrate, 13 cows fed with concentrate), three ACTH challenge tests were performed: once during pregnancy shortly prior to drying off ( T1 ), and in week 3 ( T2 ) and 8 ( T3 ) after parturition. Test characteristics were correlated to performance and metabolic parameters: DMI, BW, energy balance (EB), plasma concentrations of free fatty acids (NEFA) and beta‐hydroxybutyrate (BHB). Basal plasma cortisol concentrations were higher at T1 compared with T2 and T3 (p < .05). The adrenal cortex sensitivity (expressed as total AUC (AUC_t) of cortisol response after ACTH application) was lowest at T2 compared with T1 and T3 (p < .05). Ranking of the individual animals’ responses was not repeatable between time points of the ACTH tests. Enhancing the energy deficiency during early lactation by omission of concentrate did not affect baseline cortisol concentrations in plasma, but decreased peak height at T2 (p < .05). Baseline plasma cortisol concentrations were positively correlated with cortisol peak values after ACTH application, previous lactation performance, milk yield and BW (p < .05). The AUC_t was positively correlated with baseline cortisol concentrations, EB and DMI. Cortisol release after ACTH injection was lower in animals with high plasma concentrations of NEFA, BHB and with higher contents of fat and free fatty acids in milk (p < .05). Cortisol peak height after ACTH administration was higher in cows with a more positive EB, higher DMI and lower plasma concentrations of NEFA and BHB. In summary, cortisol responses to ACTH challenges in this study were not repeatable in dairy cows changing their physiological status.     

Morphology of alpaca (Vicugna pacos) embryos in the first third of pregnancy

The breeding of South American camelids is the main economic activity of the high Andean region of South America and it, is potentially, the most profitable resource in of the Puna environmental conditions of the Puna. The duration of the gestation in alpaca is 339.7 ± 12 days. The objective of the present work was to macroscopically and microscopically describe the ontogenic development of the splanchnic cavities of the alpaca and to determine the gestational time in which the post‐cranial ossification centers are observed in the embryos/fetuses of this species, from day 21 to 107 of gestation. The documentation of normal ontogenic development, which is vacant for this period, is of the utmost importance to understand the consequences of the alterations at the different gestational times, as well as for the estimation of the gestational age in the case of abortions. Forty‐seven alpaca specimens of both sexes, at different times of their gestational development, collected during slaughter at local slaughterhouses of the Department of Huancavelica, Peru, were evaluated. Specimens were assigned to seven groups according to their morphological characteristics. The embryogenesis in the alpaca was characterized by a series of changes comparable to those occurring in other mammals with similar gestational periods. Despite these similarities, species differences were found in some organs as stomach, which are observed too in adult individuals.     

Drugs from bugs: the use of insects as a valuable source of transgenes with potential in modern plant protection strategies

Transgenic expression of antimicrobial peptides in crops has become a novel approach among the strategies to combat phytopathogens in modern plant protection measures. The first antimicrobial transgenes of insect origin, modified cecropins, have been demonstrated to confer resistance of several transgenic cultivars against both bacterial and fungal phytopathogens. Insects represent a promising reservoir for antimicrobial peptides to engineer disease resistant crops. The increasing knowledge about the potent insect innate immunity may help to develop a novel strategy in sustainable agriculture. Several approaches are presently under investigation to prevent evolution of phytopathogens that can overcome disease resistance in transgenic crops expressing an insect antimicrobial peptide. Pathogen-induced expression of insect antimicrobial peptides in crops and combined multiple expression of different antimicrobial peptides along with proteinase inhibitors from insects may prevent selection of resistant phytopathogens. The potential of insect antimicrobial peptides as transgenes to render disease resistant crops has just started to be explored and may provide tools to be ahead of the evolutionary adaptability of phytopathogens.     

Interactive effects of elevated CO2 concentration and nitrogen supply on partitioning of newly fixed 13C and 15N between shoot and roots of pedunculate oak seedlings (Quercus robur)

Pedunculate oak (Quercus robur L.) seedlings were grown for 3 or 4 months (second- and third-flush stages) in greenhouses at two atmospheric CO2 concentrations ([CO2]) (350 or 700 micromol mol(-1)) and two nitrogen fertilization regimes (6.1 or 0.61 mmol N l(-1) nutrient solution). Combined effects of [CO2] and nitrogen fertilization on partitioning of newly acquired carbon (C) and nitrogen (N) were assessed by dual 13C and 15N short-term labeling of seedlings at the second- or third-flush stage of development. In the low-N treatment, root growth, but not shoot growth, was stimulated by elevated [CO2], with the result that shoot/root biomass ratio declined. At the second-flush stage, overall seedling biomass growth was increased (13%) by elevated [CO2] regardless of N fertilization. At the third-flush stage, elevated [CO2] increased growth sharply (139%) in the high-N but not the low-N treatment. Root/shoot biomass ratios were threefold higher in the low-N treatment relative to the high-N treatment. At the second-flush stage, leaf area was 45-51% greater in the high-N treatment than in the low-N treatment. At the-third flush stage, there was a positive interaction between the effects of N fertilization and [CO2] on leaf area, which was 93% greater in the high-N/elevated [CO2] treatment than in the low-N/ambient [CO2] treatment. Specific leaf area was reduced (17-25%) by elevated [CO2], whereas C and N concentrations of seedlings increased significantly in response to either elevated [CO2] or high-N fertilization. At the third-flush stage, acquisition of C and N per unit dry mass of leaf and fine root was 51 and 77% greater, respectively, in the elevated [CO2]/high-N fertilization treatment than in the ambient [CO2]/low-N fertilization treatment. However, there was dilution of leaf N in response to elevated [CO2]. Partitioning of newly acquired C and N between shoot and roots was altered by N fertilization but not [CO2]. More newly acquired C and N were partitioned to roots in the low-N treatment than in the high-N treatment.     

Comment on "Productivity is a poor predictor of plant species richness"

Adler et al. (Reports, 23 September 2011, p. 1750) analyzed the standardized sampling data from 48 herbaceous-dominated plant communities and concluded that "Productivity is a poor predictor of plant species richness" at fine-scale. However, their method was biased toward site-number-dominated plant communities. They also failed to provide enough data for regional analysis and detailed information for within-site analysis.     

Inhaled carbon monoxide concentration during halothane or isoflurane anesthesia in horses

OBJECTIVE: The purpose of this study was to assess carbon monoxide (CO) exposure during equine anesthesia with either halothane (H) or isoflurane (I) delivered in a circle rebreathing system. STUDY DESIGN: Prospective clinical investigation. ANIMALS: Fifty client-owned horses. METHODS: Horses were randomly assigned for anesthetic maintenance with H (n = 26) or I (n = 24). Two large animal anesthetic machines were used and assigned to a single agent for 2-4 weeks at a time. Machines were disassembled and soda lime changed prior to switching anesthetic agents. Inhalant anesthetic concentration and CO concentration were measured in gas samples obtained from the inspiratory limb of the anesthetic circuit. Values were recorded at 15 minute intervals for 90 minutes. Soda lime status (new or used) and mode of ventilation (spontaneous or mechanical) were also recorded. Data were analyzed using a five-factor ANCOVA with repeated measures. RESULTS: Inspired CO concentration for H and I increased from 1 +/- 3 and 6 +/- 11 ppm at baseline to 54 +/- 33 and 21 +/- 18 ppm at 90 min, respectively (mean +/- sd). H was associated with significantly greater CO concentrations than I at 30 to 90 min, although baseline CO was significantly greater in the I group than the H group. Oxygen flow rates were 9.9 +/- 0.5 L/min at baseline for H and I, and 5.0 +/- 0.4 and 5.0 +/- 0.7 L/min at 90 min for H and I, respectively. There were no significant differences between groups for O2 flow at any time point. Neither mechanical ventilation nor new versus used soda lime affected CO concentration. CONCLUSIONS: Significantly higher concentrations of CO were recorded during the administration of H than I. CLINICAL RELEVANCE: Levels of CO observed during the administration of either H or I for 90 minutes to horses were not clinically significant.     

Evaluation of forelimb horseshoe characteristics of thoroughbreds racing on dirt surfaces

OBJECTIVE: To describe forelimb horseshoe characteristics of horses racing on dirt surfaces and determine whether these characteristics vary with region of California, season, horse characteristics, and race-related factors. ANIMALS: 5,730 Thoroughbred racehorses. PROCEDURE: From June 17, 2000, to June 16, 2001, the characteristics of 1 forelimb horseshoe of horses that raced on dirt surfaces at 5 major racetracks in California were recorded. These characteristics included shoe type; toe grab height; and presence of a rim, pad, and heel traction devices (jar caulks, heel stickers, heel blocks, and special nails). Horse and race information was obtained from commercial records. One race/horse was randomly selected. RESULTS: 99% of forelimb horseshoes were aluminum racing plates, 35% had a pad, 23% had a rim, and 8% had a heel traction device. A toe grab was observed on 75% of forelimb horseshoes (14% very low [< or = 2 mm], 30% low [> 2 and < or = 4 mm], 30% regular [> 4 and < or = 6 mm], and 1% high [> 6 and < or = 8 mm]). Forelimb horseshoe characteristics varied with region of California, season, age and sex of the horse, race purse and distance, and track surface condition. Log-linear modeling revealed that all of these factors were significantly interrelated. CONCLUSIONS AND CLINICAL RELEVANCE: Complex interrelationships among forelimb horseshoe characteristics and region, season, age and sex of the horse, and race-related factors need to be considered when evaluating the relationships between injury and horseshoe characteristics in Thoroughbred racehorses.