Uterine Infection Influences Size and Follicular Fluid Composition of the Largest Follicle in Buffalo (Bubalus bubalis)

The effect of uterine infection on size and follicular fluid composition of the largest follicle was studied in buffalo. Reproductive tracts were collected from 102 graded Murrah buffaloes at an abattoir. Uterine infection was diagnosed by physical examination of uterine mucus, white side test and uterine cytology. Samples with pus‐containing mucus, positive reaction on white side test and/or >5% neutrophils were considered to be positive for uterine infection. Diameter of the largest follicle was measured, and follicular fluid was aspirated and assayed for nitric oxide (NO), ascorbic acid (AA), cholesterol, oestradiol (E₂) and progesterone (P₄). Infected buffaloes had smaller‐sized (p < 0.0001) largest follicles than non‐infected buffaloes. Follicular fluid collected from the largest follicle in infected buffaloes had greater (p < 0.0001) NO and P₄ concentrations coincident with lesser AA (p < 0.001), cholesterol (p < 0.0001) and E₂ (p < 0.0001) concentrations. Results indicated that uterine infection has an inhibitory effect on growth of the largest follicle in buffalo. The changes in follicular fluid composition in infected buffaloes suggest that the direct effect of uterine infection on ovarian function may be mediated through an alteration in the follicular microenvironment. Greater NO and lesser AA concentrations in the follicular fluid of infected animals are novel findings.     

Gene expression profiles in the brain predict behavior in individual honey bees

We show that the age-related transition by adult honey bees from hive work to foraging is associated with changes in messenger RNA abundance in the brain for 39% of approximately 5500 genes tested. This result, discovered using a highly replicated experimental design involving 72 microarrays, demonstrates more extensive genomic plasticity in the adult brain than has yet been shown. Experimental manipulations that uncouple behavior and age revealed that messenger RNA changes were primarily associated with behavior. Individual brain messenger RNA profiles correctly predicted the behavior of 57 out of 60 bees, indicating a robust association between brain gene expression in the individual and naturally occurring behavioral plasticity.     

A weight‐of‐evidence approach to determine estuarine fish health using indicators from multiple levels of biological organization

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Effects of irrigation, nitrogen and gypsum on yield, nitrogen accumulation and water use by wheat

Responses of wheat grown on a heavy clay soil in the Goulburn-Murray Irrigation Region of south-eastern Australia to a factorial combination of three irrigation treatments and nitrogen and gypsum application were investigated.Irrigation treatments included a rainfed control (treatment R_F) and irrigation on either a weekly (treatment I_w) or fortnightly (treatmnt I_F) basis beginning in spring and maintained until physiological maturity. Nitrogen was applied at 0 and 150 kg N ha⁻¹ (treatments N₀ and N₁₅₀, respectively) and gypsum at 0 and 5 t ha⁻¹. Nitrogen and gypsum treatments were applied at sowing.

Yield increased from a mean of 4 t ha⁻¹ treatment R_F to 6.6 t ha⁻¹ in treatments I_F and I_W, largely because of promotive effects of irrigation on kernel weight (increase from 31 mg to 42 mg kernel⁻¹ and kernel spikelet⁻¹ (1.4 as compared with 1.7). Seasonal conditions and the relative fertility of the site were sufficient to maximise spike number and spikelet spike⁻¹. Nitrogen increased kernel spikelet⁻¹ but effects on yield were not significant because of a decrease in kernel weight. Effects of gypsum on yield were not significant.

Water-use efficiency of both rainfed and irrigated treatments was ca. 1.25 g grain kg⁻¹ H₂O. However, transpirational water-use efficiency, calculated after allowing 110 mm water for soil evaporation, fell from 2 g kg⁻¹ in treatment R_F to 1.7 and 1.5 g kg⁻¹ in treatments I_F and I_W, respectively. The decrease was ascribed, in part, to lodging and soil evaporative losses may have been in excess of 110 mm with more frequent irrigation. Effects of N on water use could not be distinguished, again because of the initial fertility of the site, which supported rapid growth and resulted in complete canopy closure.

Nitrogen and irrigation treatments had independent effects on the concentration of N in the grain (%N_G) which increased by a mean of 0.6% with N treatment despite a decrease in N harvest index (HI_N) from 0.77 to .70. Irrigation decreased %N_G by approximately 0.5%. Approximately 90 kg pN ha⁻¹ was found in the grain of treatments R_FN₀, I_WN₀, I_wN₀ and R_FN₁₅₀ and differences in %N_G in these treatments attributed to a ‘dilution’ effect mediated by the increase in yield effected by irrigation. The grain accounted for approximately 115 kg N ha⁻¹ in treatments I_FN₁₅₀ and I_WN₁₅₀, countering the inverse relationship between %N_g and yield despite the increase in HI_N index caused by N application.     

Expression and Localization of Vascular Endothelial Growth Factor and its Receptors in the Corpus Luteum During Oestrous Cycle in Water Buffaloes (Bubalus bubalis)

The aim of this study was to document the expression and localization of VEGF system comprising of VEGF isoforms (VEGF 120, VEGF 164 and VEGF 188) and their receptors (VEGFR1 and VEGFR2) in buffalo corpus luteum (CL) obtained from different stages of the oestrous cycle. Real‐time RT‐PCR (qPCR), Western blot and immunohistochemistry were applied to investigate mRNA expression, protein expression and localization of examined factors. In general, all the components of VEGF system (the VEGF isoforms and their receptors) were found in the water buffalo CL during the oestrous cycle. The mRNA as well as protein expression of VEGF system was highest during the early and mid‐luteal phase, which later steadily decreased (p < 0.05) after day 10 to reach the lowest level in regressed CL. As demonstrated by immunohistochemistry, VEGF protein was localized predominantly in luteal cells; however, VEGFR1 and VEGFR2 were localized in luteal cells as well as in endothelial cells. In conclusion, the dynamics of expression and localization of VEGF system in buffalo corpora lutea during the luteal phase were demonstrated in this study, indicating the possible role of VEGF system in the regulation of luteal angiogenesis and proliferation of luteal as well as endothelial cells through their non‐angiogenic function.     

The effect of elemental Zn boluses on concentrations of Zn in serum and faeces of South American camelids

ABSTRACT

Aims: To monitor the effect of using long-acting Zn boluses on the Zn status of a group of South American camelids, using measurements of concentrations of Zn in faeces and serum.

Methods: As part of a facial eczema (FE) prevention programme, 15 camelids were treated with long-acting Zn boluses designed for preventing FE in sheep. Based on bodyweight, 13 alpacas (Vicugna pacos) received two boluses (26.4?g Zn/bolus) and two llamas (Lama glama) received three boluses. In order to monitor Zn status, measurements were made of concentrations of Zn in serum and faeces immediately prior to bolus treatment (Week 0) and 4, 6, 8 and 10 weeks later. Gamma glutamyl transferase (GGT) activity in serum was measured at Weeks 0 and 8.

Results: Two alpacas regurgitated the boluses; in one case the animal was quickly re-treated but this was not possible in the second animal. Mean concentrations of Zn in faeces were higher at all time points compared to Week 0 (p?<?0.001). Peak concentrations were measured at Week 8, and concentrations >120?mg/kg fresh weight (FW), suggested as being protective in calves, were only measured in all (13/13) treated camelids at Week 6. Mean concentrations of Zn in serum differed between weeks of sampling but changes were not consistent, and concentrations did not exceed 18?μmol/L following treatment. There was no evidence of a natural sporidesmin challenge during the study period and activity of GGT in serum of all animals was <45?IU/L.

Conclusions: Treatment with Zn boluses significantly increased concentrations of Zn in faeces but not in serum, but peak concentrations in faeces were only detected 8 weeks after treatment.

Clinical Relevance: The delay in achieving concentrations of Zn in faeces which were associated with protection against FE in calves, combined with the difficulties of administering boluses to camelids, means that we do not believe that Zn boluses should be used as the primary method for preventing FE in camelids. We recommend that FE prevention in camelids should focus on minimising spore production in pasture through the use of fungicides, grazing management and alternative forages, with boluses only used when it is thought that these methods are unlikely to provide sufficient protection against FE. Such use should always be under the guidance of a veterinarian and monitoring of serum GGT activity should be used to ensure that FE control is being achieved.     

Surgical management of bilateral diaphragmatic paralysis in a dog

Bilateral diaphragmatic paralysis of uncertain cause developed in a 3-month-old Golden Retriever. A surgical procedure for tightening the diaphragmatic muscle was used to help alleviate the dog's respiratory distress. During thoracotomy, the central tendon of the diaphragm was plicated, using an interlocking suture pattern. The dog improved after surgery, and although complete recovery from paralysis was achieved only on one side, the dog has remained clinically normal 1 year after surgery.     

High-frequency jet ventilation during pneumothorax in dogs

Pneumothorax (45 ml of N/kg of body weight insufflated into the pleural space) in anesthetized dogs ventilated with air caused a significant (P less than 0.05) increase in pleural pressure, central venous pressure, capillary wedge pressure, and venous admixture. Cardiac index (CI) and arterial O2 tensions were decreased. Ventilation with 100% O2 increased arterial O2 tensions, but did not affect calculated intrapulmonary shunting of blood or CI. Application of 10 cm of H2O-positive end-expiratory pressure in the presence of pneumothorax during positive-pressure ventilation and high-frequency jet ventilation reduced intrapulmonary shunting of blood, which remained higher than control values, and caused a further decrease in CI. Cardiopulmonary function during pneumothorax in anesthetized dogs was more profoundly affected by the application of positive end-expiratory pressure than by the form of mechanical ventilation.     

The response of two South African east coast estuaries to altered river flow regimes

1. Major reductions in catchment run‐off, a result of frequent and prolonged drought conditions, together with extensive impoundment of rivers and streams, has led to concern about the possible negative effects on downstream estuaries. Preliminary studies have shown that changes in river flow and associated nutrient inputs have had a predominantly negative impact on the aquatic biota of Eastern Cape estuaries. Natural successions now have human imposed trajectories which are reducing variability and forcing both freshwater ‘deprived’ and freshwater ‘enriched’ systems into artificial cycles. 2. The Kariega and Great Fish estuaries in the Eastern Cape Province are used in a comparative manner to illustrate how differences in riverine inflow can influence the structure and functioning of selected biotic components in permanently open systems. Maximum chlorophyll a values in the freshwater deprived Kariega Estuary were 1 μg L⁻¹, whereas maximum values in the freshwater enriched Great Fish Estuary were 22 μg L⁻¹. Mean zooplankton biomass in the lower, middle and upper reaches of the Kariega Estuary was always below 50 mg m⁻³, whereas in the same reaches of the Great Fish Estuary, these values ranged from 256 to 4253 mg m⁻³. Similarly, mean ichthyonekton densities in the mouth region of the Kariega Estuary were 49 individuals per 100 m² compared with 279 per 100 m² in the Great Fish Estuary. 3. Temporal changes of riverine flow reinforce the importance of allochthonous inputs to the functioning of Eastern Cape estuaries. A comparison between a dry and wet period in the Kariega Estuary revealed mean nitrate and phosphate concentrations increasing from 5 to 101 μmol L⁻¹ and from 1 to 5 μmol L⁻¹, respectively. Phytoplankton stocks responded positively to freshettes in both the Kariega and Great Fish estuaries. Similarly, peaks in zooplankton biomass in the Great Fish Estuary increased rapidly in response to high food resource availability resulting from elevated river discharge. The higher ichthyoplankton and ichthyonekton densities in the Great Fish Estuary, when compared with the Kariega Estuary, were attributed to a combination of stronger olfactory cues for larval immigrants from the sea and elevated food stocks in the former system. Copyright © 2000 John Wiley & Sons, Ltd.     

An index for the management of South African estuaries for juvenile fish recruitment from the marine environment

The release of fresh water from major impoundments to meet the requirements of estuaries has become a recognized need and methodologies to define appropriate release strategies have become an urgent priority in some parts of the world. A recruitment index for juvenile marine fish is presented, based on information relating to the preferred recruitment periods for 27 species, as well as the extent of dependency of these species on estuaries. The status of the estuary mouth (i.e. open or closed) and the longitudinal salinity differences (i.e. the difference between the salinity at the estuary head and the mouth) in the estuary are obtained from a hydrodynamic model of the estuary. The recruitment index integrates this information to provide an indication of potential recruitment (or recruitment opportunity). This index was applied in a case study of the Great Brak Estuary, South Africa, and a distinct decrease in the recruitment index was associated with a reduction in freshwater inflow. In the estuary modelled, annual run-off could be halved without an appreciable decrease in the fish recruitment index (FRI), but with a potentially sharp decline in fish recruitment thereafter. While the index represented recruitment opportunity rather than actual recruitment, it does at least provide an indication of where ecological risk is likely to increase substantially. Since the index integrates the current understanding with respect to the key processes which regulate recruitment of juvenile marine fish into estuaries, it is suggested that it has the potential to fulfil a vital role in identifying appropriate freshwater release policies for impoundments in South Africa.