Planning wetland protection and restoration for the safeguard of ecosystem service flows to beneficiaries

Landscape Ecology - Human activities have led to the degradation of wetlands, impinging on their capacity to deliver essential ecosystem services to society. Wetland restoration now appears an...     

Dietary levamisole modulates the immune response and disease resistance of Asian catfish Clarias batrachus (Linnaeus)

In order to determine the immunomodulatory effect of dietary levamisole in Asian catfish (Clarias batrachus), fish were fed four different diets for 10 days: a formulated diet as control and the same diet supplemented with 50, 150 or 450 mg levamisole kg^?1 feed. The serum bacterial agglutination titre against Aeromonas hydrophila as a measure of specific immunity, serum haemagglutination titre, natural haemolytic complement activity (ACH₅₀), myeloperoxidase and lysozyme activities, total protein level and oxidative radical production by neutrophils as a measure of non‐specific immunity as well as disease resistance against A. hydrophila challenge to separate vaccinated and non‐vaccinated groups were evaluated at 0, 1, 2 and 3 weeks after last administration of levamisole. Levamisole supplement at the lowest level (50 mg kg^?1) significantly enhanced oxidative radical production and serum myeloperoxidase (MPO) content immediately after 10 days of feeding, which reached peak values after 3 and 2 weeks of feeding respectively. Haemolytic complement and haemagglutination titre were significantly enhanced after 3 and 1 weeks respectively. Haemolytic complement activity and MPO activities were significantly raised to 150 mg kg^?1 after 3 and 2 weeks, respectively. At the highest level of levamisole feeding (450 mg kg^?1) significant decreases in superoxide production and complement activity were measured immediately after levamisole feeding, which returned to the normal level after 1 week post‐ feeding. Fish were challenged with a virulent strain of A. hydrophila at 0, 1, 2 and 3 weeks after levamisole feeding, and the cumulative per cent survival was recorded over 10 days. Feeding levamisole at 50, 150 or 450 mg kg^?1 increased per cent survival in vaccinated fish immediately after levamisole feeding, and survival was significantly higher at 450 mg kg^?1. There was no difference in mortality patterns in non‐vaccinated fish. The results support the use of levamisole at 50 mg kg^?1 feed for 10 days as an immunostimulant in Asian catfish farming.     

Use of an immortalized bovine mammary epithelial cell line (MAC-T) to measure the mitogenic activity of extracts from heifer mammary tissue: effects of nutrition and ovariectomy

The objectives of the experiment were (1) to determine whether MAC-T cells would accurately mimic the previously observed proliferative responses of primary mammary epithelial cells (MEC) to mammary tissue extracts from high and low-fed heifers and (2) to determine whether mammary tissue extracts from ovariectomized (OVX) heifers would have lower mitogenic activity than intact controls. Addition of mammary tissue extracts to cell culture media of MAC-T cells plated on plastic or collagen-coated plastic to a range of concentrations between 1 and 8% resulted in dose-dependent increases in cell proliferation. Furthermore, mammary tissue extracts from low-fed prepubertal heifers aged 9 months, stimulated significantly more proliferation of MAC-T cells, as measured by 3H-thymidine incorporation into DNA than mammary tissue extracts from high-fed heifers (40.6 cpm x 10(3) per well versus 21.9+/-1.8 cpm x 10(3) per well). These observations suggested that MAC-T cells would be a suitable alternative to primary MECs for measuring the mitogenic activity of mammary tissue extracts. Conversely, no difference was observed in the mitogenic activity of mammary tissue extracts from OVX or control heifers. Possibly, MAC-T cells provide a good model for nutrition- but not ovarian-induced changes in mammary growth. Alternatively, that reduction of in vivo mammary development following OVX did not result in reduced mitogenic activity of the mammary tissue extracts emphasizes that heifer mammary development is the result of complex interactions between local growth factors and systemic hormones.     

Pharmacokinetic studies of ivermectin: effects of formulation

Studies are reported which describe the effects of formulation, animal species, and route of administration on the pharmacokinetics of ivermectin. Biological half-life t1/2 increases in the order: swine (0.5 day) less than dogs (1.8 day) less than cattle approximately equal to sheep (2.8 day). Formulation modifications, based upon the solubility properties of the drug, have been directed towards the development of a nonaqueous injectable formulation for cattle and an aqueous vehicle for horses. Bioavailability following subcutaneous injection in cattle can be regulated by control of injection solvent composition: a vehicle composed of a mixed aqueous-organic solvent exhibits pharmacokinetic properties (i.e., Cp, t1/2, AUC, and F) intermediate between those furnished by an aqueous formulation and via a purely nonaqueous solvent. The longer apparent biological half-life from this latter vehicle (t1/2 = 8.3 days) confirms that a slow absorption process dominates the pharmacokinetics in the nonaqueous injectable product to produce an effective controlled-release formulation. These bioavailability results illustrate the increase in the concentration of an organic solvent and a concomitant decrease in surfactant concentration in a micellar aqueous system for prolonged drug delivery via injection.