Biomass and nutrient allocation to aboveground components in fertilized <Emphasis Type="Italic">Eucalyptus saligna</Emphasis> and <Emphasis Type="Italic">E. urograndis</Emphasis> plantations

The objective of this study was to evaluate biomass allocation and nutrient pools in aboveground biomass components in 18-month-old plantations of Eucalyptus saligna and E. urophylla × E. grandis (i.e. E. urograndis) in Brazil. The plantations were established by pulp companies in a large area comprising three soil types (Acrisols, Vertisols and Leptosols) in the grassland biome in southern Brazil, and an operational regime of planting and maintenance fertilization was used to ensure full availability of nutrients. Vertisols showed the highest availability of soil nutrients, and the P and Ca concentrations in aboveground biomass were also highest in this type of soil. The nutritional status of both species indicates great consumption of nutrients, particularly of P, K and Ca. At this early age, canopy biomass components still made the largest relative contribution, although debarked stem biomass already accounted for 41.5% and 37.4 of total aboveground biomass in E. saligna, and E. urograndis, respectively. Nutrient concentrations in biomass components were similar across species. For all macronutrients, except Ca and Mg, the concentration gradient followed the order wood < bark < branches < leaves. For all micronutrients, except Cu, the concentration gradient followed the order wood < branches ≈ bark < leaves. At the plantation stage studied, i.e. before canopy closure, the importance of the components as nutrient pools followed the order leaves > branches > wood > bark. The branches hold the majority of Ca reserves in biomass and are a very important pool of Mg, K, P and B. The bark makes a small contribution to total biomass, but stores a similar amount of Ca as leaves, being the second major pool after the branches. Comparison of the nutrients supplied by fertilization and the amounts stored in soil and aboveground indicates that the operational dose should be adjusted to each type of soil after further experimental fertilizer trials, as the supply of N and P appears to be too high, particularly for Vertisols. This is leading to the immobilization of P in biomass components that are not of importance in the biological or biochemical nutrient cycles, thus increasing the risk of larger exports of P during biomass removal.     

Serological survey of viral antibodies in llamas (Lama glama) in Argentina.

This study analysed sera from 390 llamas (Lama glama) from nine farms located in three different Argentine provinces: Buenos Aires, Cordoba and Jujuy. The samples were tested for antibodies against 8 virus known to infect cattle: bovine herpesvirus type 1 (BHV-1), bovine viral diarrhea virus (BVDV), bovine adenovirus (BAdV III), bovine enterovirus (BEV), bovine rotavirus (BRV), bluetongue virus (BTV), bovine leukaemia virus (BLV), and foot-and-mouth virus (FMDV) by conventional methods such as seroneutralization, immunoperoxidase staining, and agar gel immunodiffusion. The antibody prevalences detected in llamas were: BHV-1 in 0.77% (3/390), BVDV in 2.05% (8/390), BAdV III in 5.13% (20/390), BEV in 4.10% (16/390), BRV in 87.69% (342/390). No antibodies against BTV, BLV and VIAA (FMDV infection associated antigen) were detected.     

Characterization and functional properties of digestive proteases in two sparids; gilthead seabream (Sparus aurata) and common dentex (Dentex dentex)

Digestive proteases present in two sparids, seabream (Sparus aurata) and common dentex (Dentex dentex), have been characterized using both biochemical and electrophoretic techniques. Although optimum pH and temperature for maximum activity of both acid and alkaline proteases were similar in the two species, important differences in total activity, as well as in thermal and pH stability were found. Specific inhibitors and SDS-PAGE zymograms were used to clarify such differences. Evidences support the existence of a more active and complex protease set in dentex. Results are discussed from the perspective of their application to the formulation of feeds for each species.     

Effect of diphenyl diselenide diet supplementation on oxidative stress biomarkers in two species of freshwater fish exposed to the insecticide fipronil

The ability of diphenyl diselenide [(PhSe)₂] to attenuate oxidative damage was evaluated in the liver, gills, brain, and muscle of carp (Cyprinus carpio) and silver catfish (Rhamdia quelen) experimentally exposed to fipronil (FPN). Initially, the fish were fed a diet without (PhSe)₂ or a diet containing 3.0 mg/kg of (PhSe)₂ for 60 days. After the 60-day period, the fish were exposed to 0.65 µg/L of FPN for 192 h. The results showed that carp exposed to FPN and not fed with (PhSe)₂ exhibited acetylcholinesterase (AChE) inhibition in brain and muscle, and increased thiobarbituric acid-reactive substance (TBARS) in liver, gills, and brain. Furthermore, FPN decreased nonprotein thiols (NPSH) and δ-aminolevulinate dehydratase (δ-ALA-D) in carp liver and gills, and increased plasma glucose and protein levels. In silver catfish, FPN inhibited AChE and increased TBARS levels in muscle. In addition, glutathione S-transferase (GST) decreased in liver and muscle, and plasma glucose was increased. (PhSe)₂ reversed some of these effects. It prevented the increase in TBARS levels in liver, gills, and brain in carp and in silver catfish muscle, and reversed the increase in plasma glucose levels in both species. Additionally, (PhSe)₂ increased the NPSH levels in carp and silver catfish that had decreased in response to FPN exposure. However, (PhSe)₂ was not effective in reversing the AChE inhibition in brain and muscle or the δ-ALA-D decrease in carp liver. Thus, (PhSe)₂ protects tissues of both species of fish, mainly by preventing or counteracting the effects of FPN, on TBARS levels, antioxidants, and present anti-hyperglycemic property.     

Relationship between phosphatase active bacteria and phosphatase activities in forest soils

Acid phosphatase and alkaline phosphatase active colonies of bacteria, isolated from forest soils, were stained. The activity of acid and alkaline phosphatase and other soil properties (the number of aerobic bacteria, basal respiration, the level of ammonification, the number of bacteria active in ammonification, the level of nitrification, the number of micromycetes) were compared with the number of bacteria belonging to the genus Micrococcus. Soil samples were taken from the following horizons: F-AO1 (fermentative), H-AO2 (humic), and A (basic). The soil samples were taken from beneath forest stands in the Izera Mountains (North Bohemia, Czech Republic). The number of acid phosphatase active colonies correlated positively with the number of alkaline phosphatase active colonies in the F-AO1 horizon, and there was a high, positive correlation between the former and the level of ammonification in the H-AO2 horizon. The number of alkaline phosphatase active colonies correlated positively with organic carbon, the number of ammonification bacteria, and the number of micromycetes in the H-AO2 horizon. The A horizon was almost biologically inactive. Neither acid nor alkaline phosphatase activities correlated positively with the number of phosphatase active colonies of bacteria. Received: 6 December 1996     

Effect of ovariohysterectomy on canine postsurgical leukocyte function

The effect of surgery on phagocytic activity of blood leukocytes and mitogen-induced blastogenesis of lymphocytes was studied in fourteen dogs. Simple ovariohysterectomy with anaesthesia induced by ketamine and xylazine or by ketamine, xylazine and halothane caused a short nonsignificant depression of phagocytic activity that persisted for four hours after surgery. Ingestion capacity of leukocytes decreased significantly immediately after surgery. Mitogen-induced blastogenesis of lymphocytes was depressed significantly in the first 48 hours and despite partial recovery this parameter did not reach the value of the control groups until the end of observation (7 days). A more conspicuous decrease of blastogenic response of blood lymphocytes to mitogens was found after the use of ketamine and xylazine in a dose maintaining anaesthesia. Anaesthesia with ketamine and xylazine in the lower dose and maintained with halothane resulted in a later improvement of the blastogenic response of lymphocytes.     

Larval toxocarosis in sheep: the immunohistochemical characterization of lesions in some affected organs

Morphological and immunohistochemical responses of lambs following oral infection with 10,000 infective Toxocara canis (T. canis) eggs were studied up to 28 days post-infection (pi). The small intestine, liver, lungs and brain of both infected and control lambs were examined using the routine histological methods for paraffin sections and immunohistochemical techniques for frozen tissue sections. Eosinophil-rich hepatic granulomas and diffuse T. canis-induced pulmonary inflammation were the most prominent pathological features. CD2+, CD4+, CD8+, IgM bearing cells, and macrophages were demonstrated in the liver granulomas. The observed histomorphologic changes were similar to other paratenic hosts. It was concluded that larval toxocarosis followed the classical migratory path in the infected lambs.     

Aeromonas hydrophila Isolated from Wild Freshwater Fish in Croatia

Aeromonas hydrophila was recovered from fish living in lake Vrana on the Croatian island of Cres. The occurrence of the bacterium in the fish was assessed and related to gross signs of disease and findings at necropsy as a potential health hazard for fish. Isolated bacteria were subjected to morphological, physiological, biochemical and antibiotic susceptibility tests. A total of 26 A. hydrophila isolates were obtained. There was a clear seasonality, as no isolates were recovered in the summer months. Most of the isolates were sensitive to all the antimicrobials used in the study except novobiocin and penicillin G. Affected fish manifested haemorrhages over the skin, in the liver, kidney and swim bladder, spleen infarcts, fatty liver, ascitic fluid and swollen haemopoietic tissues. A. hydrophila does not appear to pose a major threat for the fish in the lake at present but under unfavourable and stressful conditions it could seriously compromise fish health.     

Treatment of male goats with equine chorionic gonadotrophin during the non-breeding season does not affect their sperm characteristics during the subsequent breeding season

Tropical Animal Health and Production - Equine chorionic gonadotrophin (eCG) is a hormone having FSH/LH effects. It can be used to enhance sperm quality in male goats (bucks) during the...