Bioavailability of chloramphenicol in cattle: variation with the number of injection sites and the concentration of the pharmaceutical preparation

A bioavailability study of three commercial chloramphenicol preparations was carried out in cattle in order to determine the influence of the number of muscular injection sites and the concentration of the product on the level of chloramphenicol serum concentration. Results show that chloramphenicol should be injected at the dose of 22 mg/kg at multiple injection sites to reach 5 μg/mL of serum which is considered to be the minimal inhibitory concentration.     

Entérite nécrotique chez le poulet de gril II. Caractères des souches de Clostridium perfringens isolées

A Gram positive bacillus, strictly anaerobic, was isolated from the viscera of all diseased birds showing lesions of necrotic enteritis. Its morphology and biochemical reactions, the presence of alpha and thêta hemolysins and the production of a lecithinase-C in vitro, all these characteristics indicated a similarity to those belonging to the group of Clostridium perfringens.

The two hemolysins were neutralized in vitro only by the antitoxin A. Broiler chickens injected I.V. with a Viande-Foie (VF) broth culture of Clostridium perfringens together with the antitoxin A survived, whereas those receiving antitoxin C died. These results seem to indicate that this organism belongs to the type A. This bacillus was sensitive to a great variety of antibiotics, except neomycin.

     

Semiochemical and natural product-based approaches to control Spodoptera spp. (Lepidoptera: Noctuidae)

The genus Spodoptera contains some of the most destructive crop pests in the world owing to the worldwide distribution of the different species and their wide host ranges. Uses of semiochemicals for insect control have been recently reviewed, but strategies developed specifically against Spodoptera species are scarce. In this review, we present an updated account of the semiochemicals and other natural product-based approaches to monitor and control the most damaging Spodoptera spp. In general, successful control of Spodoptera littoralis, S. frugiperda, S. litura, and S. exigua have been reported through mass trapping, mating disruption, and attract-and-kill methods. An updated survey of the pheromone components of these species and an outlook of future perspectives against these pests are also outlined.     

Single layer centrifugation of fresh dromedary camel semen improves sperm quality and in vitro fertilization capacity compared with simple sperm washing

Single layer centrifugation (SLC) through a colloid is a tool for selecting viable mammalian spermatozoa but has not been used previously for fresh dromedary camel sperm. Semen from six camels (2 ejaculates/male) was diluted 1:5 (v:v) or 1:10 (v:v) in a Tris–citrate–fructose buffer for mechanical liquefaction by gentle pipetting. Following liquefaction, semen was processed either by SLC or by centrifugation without a colloid (control). Total and progressive motilities, CASA kinematics, vitality and acrosome integrity (eosin–nigrosin) and plasma membrane integrity (Hypo‐osmotic swelling test; HOST), and fertilizing ability in a heterologous assay (zona‐free goat oocytes) were evaluated. Both total (p = .003) and progressive motilities (p = .003) were higher in SLC‐processed than in control semen samples, irrespective of dilution. Positive HOST values increased when using colloid in 1:5 (p = .001) and 1:10 dilution (p = .010). Colloid‐selected sperm had higher penetration rates than controls (p < .001 and p = .02 for 1:5 and 1:10 dilutions, respectively). However, only the SLC sperm at 1:5 dilution showed higher percentages of pronuclear formation (p = .02) than controls. Dilution effect was only significant for total motility before in vitro fertilization, with higher values for the 1:5 dilution (p = .033). The recovery rates of motile sperm between dilutions were similar (26.1% vs 35.4%; p = .226). In conclusion, SLC is a promising tool for selecting functional dromedary camel sperm and warrants more research.     

The 1949 Atlas of French peat deposits,a starting point for a national inventory of peatlands

Fifty per cent of European peatlands are in a damaged state. While intact peatlands are natural carbon sinks, degraded sites release important amounts of greenhouse gases into the atmosphere, contributing to global warming. Restoration of the hydrological functionality of peatlands has proved to be an efficient tool to avoid these emissions. In France, Tuffnell & Bignon's ministerial report (2019) emphasized the need for peatlands ‘integration into the National Low Carbon Strategy, targeting carbon neutrality by 2050. However, current knowledge regarding French peatlands’ distribution and carbon stocks is insufficient and does not allow decision makers and managers to prioritize areas for restoration. The most complete database to date is the 1949 Atlas, an inventory of exploitable peat deposits that was conducted during WWII for peat exploitation as fuel. Until its digitalization, the latter database was archived and never used in a scientific study. It provides detailed information about peatland surfaces, peat thicknesses and carbon contents at that time. We estimated peat carbon stocks from French peatlands to be 111 Mt C in 1949 for 63,290 ha identified as peaty sites, the equivalent of 3% of the organic carbon contained in the upper 30 centimetres of French soils. 34% of this stock was held in Lower Normandy (37.7 Mt C) and 12% in the Picardy's region (13.0 Mt C), in large lowland peatlands. However, not all peatlands were prospected in the 1949 inventory and the characteristics of the prospected peatlands may have changed with anthropic disturbances of the last decades, such as draining or climate change. These first results highlight the need for a recent inventory of French peatlands and carbon stocks based on local data aggregation. Data from the 1949 Atlas could help constituting this new inventory but should be validated before being used to describe the present.