蘑菇废弃菌棒及其与猪粪混合发酵对沼气产量及质量的影响

为了研究厌氧消化过程中日产气量、累计产气量和甲烷含量随厌氧消化时间的变化规律,在中温35℃±1℃条件下,采用批式单相厌氧消化工艺,分别用香菇、杏鲍菇和平菇废弃菌棒与猪粪混合发酵。结果表明,蘑菇菌棒具有很好的产气潜力,其中香菇菌棒TS产气量最高,为142.9mL.g-1,平均产气量664.1mL.d-1,杏鲍菇菌棒所产气体甲烷含量最高,平均63.8%;添加猪粪调节蘑菇菌棒C/N至25/1,对香菇菌棒前期严重酸化现象起到了很好的缓冲作用,使香菇菌棒、杏鲍菇菌棒和平菇菌棒累计产气量较单一物料分别提高了131.5%、97.9%和79.9%。研究结论为:香菇、杏鲍菇和平菇废弃菌棒均具有良好的产气潜力;添加猪粪能显著提高蘑菇菌棒累计产气量,同时提高香菇菌棒甲烷含量,降低杏鲍菇菌棒甲烷含量,对平菇菌棒甲烷含量影响不大。     

Effect of selenium and vitamin E addition to the extender on liquid stored capercaillie (Tetrao urogallus) semen quality

Captive breeding has become an important tool in species conservations programmes, maintaining genetic diversity and restoring wild, endangered populations. In order to improve the reproductive efficiency of captive kept capercaillie, the purpose of the study was to determine the effect of selenium and vitamin E addition to semen extender on sperm characteristic during short‐term storage. Ejaculates collected individually from four capercaillie were divided into two parts, diluted threefold with basic EK extender and EK enriched with 1 mg/ml of organic selenium and 8 mg/ml of vitamin E (EK+Se+E) and stored 24 hr at temp. +4°C. Spermatozoa morphology, motility and motility parameter were evaluated in net, diluted and stored semen samples. Significant (p < .05) differences between individual males were stated in relation to the majority of traits evaluated in the freshly collected semen. Comparing to the fresh semen, a significant (p < .05) decrease in percentage of live sperm in total (by 3.8% points on average) has been observed in samples diluted by EK extender, while in semen diluted with EK+Se+E extender this decrease was lower (1.5%pts on average) and not significant. Also per cent of motile sperm in EK+Se+E extender was higher (p < .05) then in EK (71.6% vs. 58.9%), but taking into account the values of individual males, both extender and male effect on liquid semen storage become apparent. Obtained data allow concluding that selenium and vitamin E addition to EK extender had positive effect on morphology and motility of capercaillie semen stored 24 hr at 4°C and can be recommended for similar studies carried out on other Galliformes species.     

Influence of fish meal and supplemental fat on performance of finishing steers exposed to moderate or high ambient temperatures.

Ninety-six Hereford x Angus steers (mean initial BW = 295 kg) were used in two growth experiments conducted at moderate and high ambient temperatures (AT), 48 steers per AT. Within each AT, calves were assigned to six dietary treatments consisting of a basal diet (approximately 60% corn and 20% grass hay) supplemented with either 0, 2.5, or 5% fat and with either soybean meal (SBM) or Menhaden fish meal (FM) included at levels such that a ratio of 16.3 kcal of NEm per kilogram of CP was maintained. Blood and ruminal fluid were collected 40 d before slaughter. During the final 28 d of the moderate AT experiment, apparent digestibility of dietary components was measured in four individually fed steers from each dietary treatment. Steer ADG was not affected by fat, and DMI and efficiency of gain were not affected (P > .10) by treatment. Average daily gain was lower for steers fed FM than for those fed SBM at moderate AT but higher at high AT (CP source x AT interaction; P < .05). Ruminal ratio of acetate to propionate declined linearly with increasing fat at moderate AT but was not affected by fat at high AT (fat x AT interaction trend; P = .08). Plasma urea N concentration increased linearly (P < .05) with increasing fat and was higher (P < .05) in steers kept at high than in those kept at moderate AT. Although apparent digestibility was not altered in steers fed FM, DM and NDF (P < .05) and ADF (P = .07) digestibility decreased with increasing fat in steers fed SBM (CP source x fat interaction).(ABSTRACT TRUNCATED AT 250 WORDS)     

Luteal maintenance in cattle after conceptus death during the first trimester of gestation.

The objectives of this experiment were to evaluate effect of age of the conceptus at death on subsequent interval to estrus and to determine whether prostaglandin F2 alpha (PGF) treatment after induced conceptus death would reduce interval to estrus. Sixty-four beef cows were diagnosed pregnant by ultrasonography between 24 and 50 d of gestation. Nine pregnancy groups were identified; each encompassed a 3-d interval from d 24 through 50 of gestation. Cows were allocated at random within pregnancy group to be treated with colchicine to induce conceptus death. Forty-eight hours after colchicine treatment, conceptus death was verified by ultrasonography and each animal received either saline or PGF. There was no evidence of an effect of age of conceptus at death on the subsequent interval to estrus after either saline or PGF. Interval to estrus after saline was 13.5 +/- .8 d, which was greater (P less than .01) than the 6.2 +/- .8 d after PGF. After saline, the estimate for the linear effect of time on serum progesterone (P4) was -1.32 +/- .36 ng/d and was less (P less than .05) than -2.83 +/- .36 ng/d for cows given PGF. Cows were exposed to fertile bulls at the first postabortion estrus. Pregnancy rates were 37.5% for cows given saline vs 31.3% for those given PGF. These results indicate that interval to estrus after conceptus death between 24 and 50 d of gestation is not affected by the age of the conceptus and can be reduced by PGF treatment.     

Effects of hydrochloric,acetic, butyric,and propionic acids on pathogenesis of ulcers in the nonglandular portion of the stomach of horses

OBJECTIVE: To identify the pathogenesis of gastric ulcers by comparing injury to the nonglandular gastric mucosa of horses caused by hydrochloric acid (HCl) or volatile fatty acids (VFAs). SAMPLE POPULATION: Gastric tissues from 30 horses. PROCEDURE: Nonglandular gastric mucosa was studied by use of Ussing chambers. Short-circuit current (Isc) and potential difference were measured and electrical resistance calculated for tissues after addition of HCl and VFAs to normal Ringer's solution (NRS). Tissues were examined histologically. RESULTS: Mucosa exposed to HCl in NRS (pH, 1.5) had a significant decrease in Isc, compared with Isc for mucosa exposed to NRS at pH 4.0 or 7.0. Also, exposure to 60mM acetic, propionic, and butyric acids (pH, 4.0 or 1.5) caused an immediate significant decrease in Isc. Recovery of sodium transport was detected only in samples exposed to acetic acid at pH 4.0. Recovery of sodium transport was not seen in other mucosal samples exposed to VFAs at pH < or = 4.0. CONCLUSIONS AND CLINICAL RELEVANCE: Acetic, butyric, and propionic acids and, to a lesser extent, HCl caused decreases in mucosal barrier function of the nonglandular portion of the equine stomach. Because of their lipid solubility at pH < or = 4.0, undissociated VFAs penetrate cells in the nonglandular gastric mucosa, which causes acidification of cellular contents, inhibition of sodium transport, and cellular swelling. Results indicate that HCl alone or in combination with VFAs at gastric pH < or = 4.0 may be important in the pathogenesis of gastric ulcers in the nonglandular portion of the stomach of horses.     

Comparison of endoscopic,necropsy and histology scoring of equine gastric ulcers

Equine gastric ulcer syndrome (EGUS) represents a major health problem in performance horses. Much debate exists regarding endoscopic gastric ulcer scoring systems and their ability accurately to predict severity or depth of gastric ulcers. The purpose of this study was to evaluate the ability of an endoscopist to count gastric ulcers and predict gastric ulcer severity or depth using 2 endoscopic scoring systems and compare them to the same gastric ulcers see on necropsy and histopathology. Endoscopic examination of the stomach was performed under general anaesthesia on 23 mixed breed yearling horses, after feed was withheld for 24 h. Gastric ulcers were scored using 2 systems, number/severity-scoring (N/S) and practitioner simplified (PS) systems. After endoscopy, the horses were subjected to euthanasia and the stomach mucosa examined blindly and scored again at necropsy using above scoring systems. Representative gastric ulcers were then placed in 10% formalin and processed routinely for histopathology. The gastric ulcers were scored using a histopathology system (HSS) based on ulcer depth. Number scores in the N/S scoring system and PS on endoscopic and necropsy examinations were compared using Friedman 2 way analysis of variance. Where significant differences between variables were found a post hoc analysis was conducted using a Tukey's Studentised range (HSD) test. Severity scores using the N/S (ENGS) and PS scores recorded for the stomach via endoscopy and scores from HSS were evaluated for significant association using a Mantel-Haenszel Chi-square and Pearson moment correlation coefficient analysis. Significance was P < 0.05. All horses had gastric ulcers in the nonglandular mucosa via endoscopic examination and at necropsy examination. Mean nonglandular ulcer number (ENGN) score was significantly (P = 0.0024) lower on endoscopic examination compared to the score at necropsy (NNGN); whereas PS scores were not significantly different on endoscopy when compared to necropsy examination. A significant but weak association was found between ENGS and HSS (3.89, P = 0.048; r = 0.453, P = 0.045) and no correlation was found between PS and HSS (1.2, P = 0.272; r = 0.117; P = 0.622). Only 1/23 horses had glandular ulcers observed via endoscopic examination whereas, 6/23 horses had glandular ulcers at necropsy and on histopathology. The prevalence of EGUS is high in stalled yearling horses. The endoscopist may underestimate the number of gastric ulcers and may not be able accurately to predict the severity or depth of those ulcers present in the nonglandular equine stomach. Furthermore, the endoscopist may miss glandular gastric ulcers.     

Validation of the FACSCount AF System for Determination of Sperm Concentration in Boar Semen

A flow cytometric method has been developed for rapid determination of sperm concentration in semen from various mammalian species. * * Patent Pending, Int. Publication Number WO/00/54026.
All cells containing DNA are stained with SYBR‐14 or propidium iodide (PI) and sperm concentration is determined in relation to an internal standard of fluorescent microspheres (beads). Satisfactory staining can be achieved within 2–3 min and the following flow cytometric analysis on the FACSCount AF System rapidly provides the user with a precise and accurate assessment of the sperm concentration. In this study, the FACSCount AF System and Sperm Counting Reagent (BD Biosciences) was compared with microscopic counting using a Bürker–Türk haemocytometer. In addition, sperm concentration was determined using the Corning 254 spectrophotometer which is used routinely by Danish artificial insemination stations for boars. The results show that the agreement between flow cytometry and microscopic counting is very high. The slope for the regression line was 1.12 (SE = 0.03) with an estimated intercept with the Y‐axis of 22 × 10⁶sperm/ml (SE = 10 × 10⁶ sperm/ml) and an estimated error of the model of 10 × 10⁶ sperm/ml. For the spectrophotometer, the slope of the regression line was 1.09 (SE = 0.07) with an estimated intercept of 137 × 10⁶ sperm/ml (SE = 25 × 10⁶ sperm/ml). The average error made by the spectrophotometer was 55 × 10⁶ sperm/ml. In addition, the results obtained using flow cytometry was highly repeatable (CV = 2.7%) in comparison with the spectrophotometric method (CV = 6.3%). These results indicate that the FACSCount AF System is a valuable tool for precise and accurate assessment of sperm concentration in boar semen and that use of this system may lead to production of more uniform insemination doses containing a specific number of sperm per dose.     

The effect of autonomic manipulation on heart rate variability in dogs

Beat‐to‐beat variation of heart rate is reflective of autonomic balance and has been used to assess pain and stress in human beings. The purpose of this investigation was to pharmacologically manipulate the autonomic nervous system and to determine the effect of these manipulations on heart rate variability (HRV) in dogs. Four adult male hound dogs (27 ± 1 kg) were used in the investigation. Each dog was given five treatments: Parasympathetic blockade (glycopyrrolate; 0.01 mg kg^–1 IV and 0.01 mg kg^–1 IM), parasympathetic stimulation (phenylephrine; 0.005 mg kg^–1 IV + 0.05 mg kg^–1hour^–1), sympathetic blockade (propranolol; 0.11 mg kg^–1 IV), sympathetic stimulation propranolol; 0.01 μg kg^–1 minute^–1), and saline control. At least 48 hours were allowed between treatments. ECG recordings were obtained using an ambulatory ECG monitor. A 5‐minutes period of continuous recording obtained ~30 minutes after initiation of drug administration was used for data analysis. Changes in HRV were evaluated by time and frequency‐domain analysis. The standard deviation of normal R‐R intervals (SDNN), as well as the standard deviation of successive differences in RR intervals (SDSD) were assessed for each treatment. Low frequency (LFP; 0.05–0.15 Hz), high frequency (HFP; 0.15–0.35 Hz), and total (TP; 0.017–0.5 Hz) spectral power were also determined. The LFP:HFP ratio was also evaluated. A two‐way anova with a Tukey's test was used to detect differences (p < 0.05). Administration of glycopyrrolate or isoproterenol increased HR and decreased SDNN and SDSD below control levels. Phenylephrine or propranolol administration were without effect. LFP was diminished by glycopyrrolate and isoproterenol, but was unaffected by phenylephrine and propranolol. HFP, TP, and LFP:HFP were unaffected by treatment. Both branches of the autonomic nervous system influence SDNN and LFP. SDSD, in contrast, is altered primarily by parasympathetic activity. Thus, it appears that parasympathetic activity modulates HRV in the resting dog, as either withdrawal of parasympathetic influence or accentuated sympathetic activity led to significant changes in these measures of HRV. Conversely, augmentation of parasympathetic activity or withdrawal of sympathetic tone minimally affected HRV.     

A function for kinesin I in the posterior transport of oskar mRNA and Staufen protein

The asymmetric localization of messenger RNA (mRNA) and protein determinants plays an important role in the establishment of complex body plans. In Drosophila oocytes, the anterior localization of bicoid mRNA and the posterior localization of oskar mRNA are key events in establishing the anterior-posterior axis. Although the mechanisms that drive bicoid and oskar localization have been elusive, oocyte microtubules are known to be essential. Here we report that the plus end-directed microtubule motor kinesin I is required for the posterior localization of oskar mRNA and an associated protein, Staufen, but not for the anterior-posterior localization of other asymmetric factors. Thus, a complex containing oskar mRNA and Staufen may be transported along microtubules to the posterior pole by kinesin I.