Effect of pre-anesthetic meperidine on gastro-esophageal reflux in anesthetized dogs

Meperidine has been shown to decrease lower esophageal sphincter tone in monkeys and people, to have little effect in cats, and to physically increase it in dogs. We hypothesized that administration of meperidine to dogs before anesthesia would decrease the probability of GER during the subsequent anesthetic. In this randomized, prospective clinical trial we aimed to determine the incidence of GER in dogs undergoing elective orthopedic surgery and receiving either meperidine or morphine prior to anesthesia. Dogs were admitted to the study, if they were healthy, with no history of vomiting or dysphagia. Dogs were fasted overnight. Dogs were received either morphine (0.66 mg kg^–1 IM) or meperidine (8.8 mg kg^–1 IM) with acepromazine. Anesthesia in all dogs included thiopental and isoflurane in oxygen. To measure esophageal pH a sensor-tipped catheter was placed with the tip 5–7 cm cranial to the lower esophageal sphincter, and connected to a computer for continual data collection. Dogs were observed for vomiting after pre-medication, and the pH of any fluid running from the mouth or nose during anesthesia was measured. Gastro-esophageal reflux was defined as a decrease in esophageal pH below 4 or an increase above 7.5 for greater than 15 seconds. One-way anova was used to test significance of differences between groups in parametric variables. Fisher's Exact test was used to test significance of differences in incidence between groups. In dogs receiving meperidine the incidence of vomiting was 0, and of GER was 31% (4/13), compared to 60% (6/10) and 60% (6/10), respectively in dogs receiving morphine. In this preliminary study, the administration of pre-anesthetic meperidine was associated with a 29% reduction in the absolute risk of GER compared to morphine.     

Moho offset across the northern margin of the tibetan plateau

Anomalous double-pulse teleseismic P-wave arrivals were observed at one station near the northern margin of the Tibetan Plateau. The azimuthal dependence of the waveform distortion and its absence at nearby stations indicated that the distortion was produced by receiver-side crustal heterogeneity. Modeling of the three-component data revealed a 15- to 20-kilometer Moho offset that occurs over a narrow lateral range of less than 5 kilometers. This east-west-striking offset separates the thick Tibetan Plateau crust from the Qaidam Basin crust. Such a sharp crustal thickness change implies a weak Tibetan Plateau crust that thickens vertically in response to penetration by India from the south and to blockage caused by a strong Qaidam Basin crust to the north.     

Incidence of leptospiral abortion in Brazilian dairy cattle

We examined dams' paired serum samples and foetal kidneys (histopathologically and attempting leptospiral cultures) from 120 Brazilian Holstein abortions from 10 herds near Sao Paulo, Brazil, in 1996. Leptospiras was isolated from 15 foetuses. The Leptospira interrogans serovar hardjo was obtained from four, pomona from three and wolffi from eight foetuses. Ten of these 15 foetuses showed a four-fold rise in titres between the day of abortion and the second samples taken 15 days later. Fifty-seven other foetuses had histologic evidence of leptospires; 27 of their dams (47%) had four-fold rises in titres. In total, 72 of 120 aborted foetuses had evidence of leptospiral infection.     

Assessment of field fertility and several in vitro sperm characteristics following the use of different Angus sires in a timed-AI program with suckled Nelore cows

In order to provide information that may help researchers to understand the main cause(s) of differences in bull fertility frequently observed in field trials, this study aimed to investigate conception rates as well as several in vitro sperm characteristics of different sires of unknown fertility utilized in a Timed-AI (TAI) program. Suckled Nelore cows submitted to the same TAI protocol were allocated into eight breeding groups of approximately 120 animals each. Frozen semen doses from three Angus bulls and three different batches from each bull were utilized. Approximately 100 doses from each batch were used in TAI. Sires, batches and AI technicians were equally distributed across breeding groups. Cows were examined for pregnancy diagnosis 40 d after TAI. For in vitro sperm analyses, the same thawing procedure was repeated in the laboratory to mimic field conditions. The following in vitro sperm characteristics were assessed: computerized motility, thermal resistance, plasma and acrosomal membrane integrity, lipid peroxidation, morphology, morphometry and chromatin structure. No effect of breeding group, body condition score, AI technician and sire was observed. However, some significant differences among bulls were detected in laboratory analyses. Semen from sire presenting numerically lower (P > 0.05) pregnancy/AI also presented lower (P < 0.05) values in all sperm characteristics analyzed in thermal resistance test at 4 h (Total Motility, Progressive Motility, Average Path Velocity, Straight-Line Velocity, Curvilinear Velocity, Amplitude of Lateral Head Displacement, Beat Cross Frequency, Straightness, Linearity, and Percentage of Rapidly Moving Cells), higher (P < 0.05) Major and Total Defects in sperm morphological test, lower (P < 0.05) Length, Ellipticity and Fourier parameter (Fourier 0) in sperm morphometric analysis as well as higher (P < 0.05) chromatin heterogeneity. It was concluded that, although no bull effect was observed in the field experiment, the sire that presented numerically lower pregnancy/AI also presented lower semen quality according to the laboratory analyses performed.     

Diallel analysis of maize inbred lines for carotenoids and grain yield

Vitamin A deficiency causes xerophthalmia in preschool-aged children worldwide. The objective of this study was to estimate the genetic parameters that would be useful in selecting parent plants for developing productive hybrids with higher levels of provitamin A in the maize kernel. A complete 7 × 7 diallel mating scheme was used to generate 21 single-cross hybrids. The F₁ crosses and check hybrids were evaluated in complete block design across three different Brazilian environments, and carotenoid content was analyzed by high performance liquid chromatography. General combining ability effects were significant for all traits except α-carotene This result indicates that the contribution of the additive effect was more important for provitamin A and other carotenoids and, consequently that there is high chance of improving this trait through recurrent selection methods. Line 3 produced the highest level of kernel provitamin A among the inbred lines evaluated and also demonstrated the potential to contribute to the development of genetic materials with a good performance for provitamin A. Inbred lines 1, 6, and 7 showed a higher concentration of favorable alleles for grain yield, and inbred lines 3 and 6 exhibited a higher concentration of favorable alleles for β-carotene. Hybrid 1 × 3 performed well in terms of provitamin A and grain yield and combination 2 × 3 was the best performer in terms of lutein content.     

Performance and intestinal microbiota of chickens receiving probiotic in the feed and submitted to antibiotic therapy

The purpose of this study was to verify the ability of a probiotic in the feed to maintain the stability of the gut microbiota in chickens after antibiotic therapy and its association with growth performance. One thousand six hundred twenty 1‐day‐old Cobb male were housed in floor pens (36 pens, 45 birds/pen) and were fed corn‐/soya bean meal‐based diets supplemented with or without probiotic (Bacillus subtilis) during the entire rearing phase. From 21 to 24 days of age (three consecutive days), the chickens were submitted to antibiotic therapy via drinking water (bacitracin and neomycin) in order to mimic a field treatment and induce dysbiosis. Growth performance was monitored until 42 days of age. At 2, 4 and 6 days after antibiotic therapy, three chickens from each pen were euthanized and the contents of the small intestine and caeca were collected and pooled. The trial was conducted with four treatments and nine replicates in a 2 × 2 factorial arrangement for performance characteristics (with and without probiotic × with and without antibiotic therapy); for the intestinal microbiota, it was in a 2 × 2 × 3 factorial arrangement (with and without probiotic × with and without antibiotic therapy × 2, 4 and 6 days after the antibiotic therapy) with three replicates per treatment. Terminal restriction length polymorphism (T‐RFLP) analysis showed that the structure of gut bacterial community was shaped by the intestinal segment and by the time after the antibiotic therapy. The number of 16S rDNAs copies in caecum contents decreased with time after the therapeutic treatment. The antibiotic therapy and dietary probiotic supplementation decreased richness and diversity indexes in the caecal contents. The improved performance observed in birds supplemented with probiotic may be related to changes promoted by the feed additive in the structure of the intestinal bacterial communities and phylogenetic groups. Antibiotic therapy modified the bacterial structure, but did not cause loss of broiler performance.