Natural Stable Isotopes for Determination of Gastrointestinal Transit Time in Fish

This study evaluated the application of stable isotopes of carbon as an alternative and more accurate method to determine gastrointestinal transit time (GTT) in fish by comparing it to the inert marker method. The stable isotope method detects alterations of the normal carbon flow in a biological system by analyzing naturally occurring isotopes of carbon, contrary to studies based on conventional techniques that apply external markers to the diet to determine GTT through visual observation of the color change in feces. Therefore, 320 pacu, Piaractus mesopotamicus juveniles were reared in 32 tanks under two different temperatures (25 and 29 C). The pacu juveniles received two different diets, one based on ingredients derived from C₃ photosynthetic cycle plants and the other based on C₄ plant ingredients, both containing titanium oxide (TiO₂) as a marker. After 40 d, the isotopic signature of the diets was changed, and the marker was replaced by chromic oxide (Cr₂O₃). In the isotopic technique, the feces were analyzed to determine the exchange in the isotopic ratio of carbon δ¹³C. Both methods found that GTT was faster (nearly 6 h) in fish at 29 C when using the C₄/C₃ feeding strategy and slower in fish at 25 C using the C₃/C₄ strategy (15 h by inert marker and 18 h by the isotopic method). In conclusion, GTT determination in pacu juveniles using the stable isotope technique exhibits the same accuracy obtained with the inert marker method at temperatures suitable (nearly 29 C) for the metabolism of these animals.     

Diverticulum of the third ventricle and absence of the interthalamic adhesion in a dog

A 10-month-old male Pomeranian dog was examined for neurological abnormalities consistent with diffuse forebrain and cerebellar disease. Based on ultrasound and magnetic resonance imaging (MRI) a diagnosis of diverticulum of the third ventricle, partial agenesis of the corpus callosum, and absence of the interthalamic adhesion was made. As conservative treatment was unsuccessful, a ventriculoperitoneal shunt was placed.     

Does reverse growth dominance develop in old plantations of Eucalyptus saligna?

Patterns of stand growth and dominance among individual trees change through stand development. We tested a prediction that large, old plantations of Eucalyptus saligna (Sm.) in Hawaii and Brazil would show a pattern of “reverse” growth dominance, with the largest trees contributing more to stand biomass than to current stand increment. This pattern might develop if the largest trees accounted for a large portion of the total resource use of the stand, but were less efficient at utilizing resources to produce stemwood. The 70-year-old plantation in Hawaii had a stem mass of 610 Mg/ha, compared with 325 Mg/ha in the 66-year-old Brazil plantation. Cumulative frequency plots for both sites showed that dominant trees comprised a very large proportion of total stand mass; the largest 20% of the trees accounted for 50% and 30% of the total stand mass in Hawaii and Brazil, respectively. Contrary to expectations, the largest trees continued to produce a disproportionately large amount of total stand growth, with the largest 20% of trees accounting for 60% (Hawaii) and 40% (Brazil) of stand growth. The frequency distributions resulted in positive growth dominance coefficients (similar to Gini coefficients) of 0.14 for Hawaii and 0.09 for Brazil, rather than negative values that would indicate that reverse growth dominance. The failure of these monoculture Eucalyptus stands to develop reverse growth dominance contrasts starkly with a variety of studies with pine species, which tend to show neutral-to-reverse growth dominance. Indeed, continued dominance of large trees suggests the trees might respond well to silvicultural treatments such as thinning or fertilization. Future work that contrasts patterns of growth dominance among species will be important as a foundation for developing generalizations about trends in growth dominance with stand development.     

Synthesis and toxicological properties of some alkyl and aryl 3,4-methylenedioxyphenyl N,N′-thio-bis-N-methylcarbamates

A series of asymmetrical thio-bis-N-methylcarbamate derivatives were synthesised by combining 3,4-methylenedioxyphenyl N-methylcarbamate with different N-methylcarbamates. Some of these derivatives combined good insecticidal activity against the housefly with reduced acute oral toxicity to mice. The thio-bis-N-methylcarbamates obtained exhibited a lower anti-cholinesterase activity than the more toxic of the two carbamate moieties contained in each combination. The weak synergism of piperonyl butoxide on the insecticidal activity of the derivatives suggests the possibility of a self synergism phenomenon caused by the 3,4-methylenedioxyphenyl group.     

Effect of the fungicide imazalil on hepatic microsomal cytochrome P-450 and cytochrome P-450 dependent activities in the Bobwhite quail (Colinus virginianus)

Bobwhite quails were treated with imazalil for 8 weeks. The fungicide was given admixed in the food at 0, 100, 300, 500 and 1000 mg kg^?1. Even at the highest dose tested, imazalil did not affect the liver weight or the hepatic microsomal protein content. In treated quails, no significant induction of cytochrome P-450 or NADPH-cytochrome c-reductase activity was observed. Furthermore, imazalil did not induce or inhibit 7-ethoxyresorufin or 7-ethoxycoumarin O-deethylase in quail microsomes. Only a slight but significant increase by 35% and 49% in aniline hydroxylase activity was measured for the 500- and 1000-mg kg^?1 dose levels, respectively. After a drug-free period of one week, aniline hydroxylase activity returned to control values, indicating that the effect was fully reversible. It is concluded that imazalil does not induce or inhibit drug-metabolizing enzymes in the quail, even at doses which exceed by far the maximum levels currently used to dress seed under field conditions (100 mg kg^?1).     

New mite-borne virus isolates from rakkyo,shallot and wild leek species

Flexuous viruses were transmitted from rakkyo (Allium chinense) and wild leek species (especiallyA. commutatum) to plants of crow garlic (A. vineale), by transfer of dry bulb mites. By electron microscope decoration tests using three antisera and by inoculations onto test plants, it was concluded that from each of the two natural host species at least two viruses were isolated. The viruses from wild leeks are both pathogenic onAllium spp. and may be of economic importance. Decoration tests on a virus mixture from shallot obtained earlier, revealed another new mite-borne virus in this species. The mite-borne viruses ofAllium spp. appear to be very common; they are largely diverse and their identification remains difficult.     

Modelling the microbial breakdown of pesticides in soil using a parameter estimation technique

Results of field measurements and laboratory experiments were used to simulate the behaviour of 1,3-dichloropropene (1,3-D) in a loamy sand soil. Microbial activity was described using pre-set conditions to compute transformation rates as dependent on compound concentrations and temperature. These kinetics could only be analysed using non-linear transformation rates. To link the development of microbial populations and the consumption of the compound over time, an iterative technique was used to estimate the necessary parameters.     

Crude protein fractions in common vetch (Vicia sativa L.) fresh forage during pod filling

Crude protein (CP) of forages can be separated into fractions of differentiated abilities to provide available amino acids in the lower gut of ruminants. This knowledge is critical to develop feeding systems and to predict animal responses. We have measured during two growing seasons (1996 to 1997 and 1997 to 1998) the CP fractions of common vetch fresh forage with the objective being to assess the influence of maturity on concentration of CP fractions (as a percentage of total CP) and fraction yields. Fraction B2, which represents true protein of intermediate ruminal degradation rate, was the largest single fraction in common vetch forage (about 40% of CP across seasons and maturity stages). Soluble fractions (A plus B1) were less than 50% of total CP while the unavailable fraction C ranged from 4 to 8% of total CP. As a result, the remaining fraction B3 (true protein of very low degradation rate) only represented 2 to 9% of total CP. Concentration and yield of fraction B3 increased (P < 0.05) from flowering to pod-filling. Results showed that undegraded dietary protein represented a small proportion of total CP in common vetch forage. Moving the harvesting stage from flowering to the pod filling phase allowed for greater yield of undegraded dietary protein.     

Disease and mortality on red deer farms in New Zealand

A longitudinal observational study of 15 red deer farms was carried out in New Zealand for two years from March 1992. The deer were monitored for performance and health problems, and farm management practices were recorded. Numbers at risk were 4,683 hind-years, 2,459 stag-years and 3,202 weaner-years. The numbers of primiparous and adult hinds at risk of losing their progeny by weaning were 653 and 3,364, respectively. Where possible, postmortem examinations were carried out, and organs were sampled for histological and microbiological investigation. Rates of mortality varied with season with most stag and hind deaths in winter and weaner deaths in autumn and winter. Overall mortality rates were 1.77, 2.60 and 5.87 per 100 deer-years for hinds, stags and weaners, respectively. Malignant catarrhal fever accounted for 0.53 stag and 0.17 hind deaths per 100 deer-years at risk Misadventure, including broken bones, accounted for 15.4 per cent of weaner mortalities, or 0.53 weaner mortalities per 100 weaner-three months in autumn. Yersiniosis was confirmed in 18.6 per cent of weaner deaths, or 1.09 weaners per 100 weaner-years during the first six months after weaning, but was also suspected but unconfirmed in a further 41 per cent of weaner mortalities. Overall, 17 per cent of yearling hinds, and 9.2 per cent of adult hinds lost their progeny between pregnancy diagnosis in June and weaning in March. One outbreak of osteochondrosis was recorded. Mortality rates varied between farms and many mortalities were preventable.     

Open reduction of sacral fractures using transarticular implants at the articular facets of L7-S1: 8 consecutive canine patients (1995-1999)

OBJECTIVE: To describe and evaluate facet stabilization as an aid for open reduction and fixation of sacral fractures. STUDY DESIGN: A clinical case series. STUDY POPULATION: Eight consecutive client-owned dogs with sacral fractures. METHODS: A combination of a standard lateral approach to the ilium and a dorsal approach to the articular facets of L7-S1 was performed. The articular facets were reduced and stabilized with a Kirschner wire or a combination of a Kirschner wire and a cortical screw. Primary stabilization of the sacrum was then accomplished using a cortical screw inserted from the lateral aspect of the ilium, through the sacral fracture into the body of the sacrum. Accuracy of reduction, position of the implants, percent screw depth/sacral width, pelvic canal diameter ratio, and complications were assessed using radiographs and physical examination. RESULTS: Mean sacral fracture reduction was 91% immediately after surgery, and was 87% when measured at follow-up examinations. Mean screw depth/sacral width was 66%. Mean pelvic canal diameter ratio was 1.12 postoperatively and 1.03 at the 4- to 6-week reevaluation. Six of the 8 dogs were using the leg well 10 to 12 days after surgery; none had clinically detectable neurologic deficits. The long-term (mean, 2.7 years) outcome for these dogs was good (normal to grade I lameness). CONCLUSION: Fixation of the L7-S1 facet joints facilitates repair of sacral fractures.