Effect of dietary conjugated linoleic acid and monounsaturated fatty acids on productive, carcass and meat quality traits of pigs

Three levels (0, 1 and 2%) of conjugated linoleic acid (CLA) were combined with two levels (low and high) of monounsaturated fatty acids (MUFA) for pig feeding. Productive, carcass and meat quality traits were studied. Large White ♂ × Landrace × Large White ♀ gilts (n = 288) weighting 70 kg were randomly allotted to 6 different feeding treatments and fed to a final average weight of 107 kg. Loins were taken from 48 animals (8 animals randomly selected from each treatment). No differences due to dietary CLA, MUFA or CLA × MUFA interaction were found on average daily gain, average daily consumption, feed conversion ratio, carcass yield, backfat thickness, loin weight, loin pH and loin colour. A significant increase in intramuscular fat content (p = 0.010) and in saturated fatty acids (SFA) (p < 0.001), and a decrease in MUFA (p = 0.001) and desaturase indices were found as consequence of dietary CLA, regardless the MUFA level. Therefore, dietary CLA, MUFA and their interaction did not influence productive and carcass traits of pigs. However, the use of CLA for swine feeding increased the intramuscular fat content and modified the fatty acid profile, regardless the MUFA level of the diets.     

The role of grazing in creating suitable sward structures for breeding waders in agricultural landscapes

French wet grasslands support important populations of lapwings and other waders. Grazing management is a key issue in the use of grasslands by these birds since they are very sensitive to sward structure (height and heterogeneity). To assess the impact of different grazing regimes on sward structure during spring, sward height was repeatedly measured in a coastal marsh for 2 years. Sward structure was characterised by variables related to height classes and an index of heterogeneity. Grazing regimes were described by stocking rates per period and N fertilisation level. Heterogeneity index was quadratically related to mean sward height both years. Four types of sward structures were characterised through principal component analysis. Co-inertia analysis showed a strong relationship between grazing regimes and sward structure. However, during spring, the relationship between stocking rate and sward structure differed according to year, impact of grazing being greater during drought year. Suitable sward structures were observed for both lapwings and redshanks. Wader habitat management through grazing calls for more attention to be paid to the delayed effects of autumn and winter grazing regimes. Sward heterogeneity emerges as a new characteristic to control, because it may introduce new constraints for livestock production.     

Cytologic and histologic features of a poorly differentiated glioma in a dog

A 5-year old female Boxer with a 1-week history of progressive paresis and paraplegia had a T10-13 subarachnoid filling defect on myelography. Exploratory hemilaminectomy revealed an intramedullary spinal cord tumor which was subsequently diagnosed as a poorly differentiated glioma, most likely an anaplastic ependymoma. The cytologic, histologic, and immunocytochemical staining characteristics of this neoplasm are described. Differential diagnoses, including primary and secondary tumors involving the central nervous system are discussed.     

Detection and estimation of Citrus Tristeza Virus infection rates based on Elisa Assays of packing house fruit samples

Enzyme-linked immunosorbent assay (ELISA) proved to be a sensitive detector for citrus tristeza virus (CTV) in orange fruits (Citrus sinensis (L.) Osbeck). Samples of five fruits were taken from 350-kg packing house containers and tested by ELISA to predict the infection rate of CTV in two infected orange groves. The predicted infection rates, 1% and 11%, were in reasonable agreement with the observed rates of 1% (15/1400) and 16% (324/2053), respectively. The 360 test samples from reputedly uninfected groves all tested negative. These results suggest that the ELISA procedure may provide a general method of detecting viral or other systemic pathogenic infections using the fruit as the test material in place of tree tissue. Fruit samples can be collected routinely at the packing house to reduce test costs.     

Kinetics of Uptake and Metabolism of Atrazine in Model Plant Systems

The present work concerns atrazine absorption and metabolism by corn (Zea mays.) seedlings immersed in an aqueous medium in comparison with Acer pseudoplatanus cell cultures. At the point of equilibrium, the apparent concentration inside the A. pseudoplatanus cells (with a moderate lipid content: 0·17% of dry weight) was about twice that of the medium. This equilibrium was probably due to a simple partition process; part of the atrazine was dissolved in the cell water and reached the same concentration as in the external medium while the rest was concentrated inside the cellular lipids. The theoretical calculation of the lipid/water partition, taking into account the value of log P measured not with the lipids but with octanol (log P=2·5), gave a value of 1·5 for concentration inside the plant material. Such an equilibrium, resulting from a partition process between water and lipids, was also obtained in non-living corn seedlings. In living seedlings, an over-concentration of radioactivity due to [¹⁴C]atrazine derivatives was rapidly obtained inside roots and shoots giving concentrations respectively 7- and 12-fold higher than that of atrazine in the external medium. This was due to very rapid chemical transformation of atrazine into its hydroxy derivatives, especially hydroxyatrazine. This hydrolysis of atrazine in corn was due to the presence of high levels of benzoxazinone derivatives in corn seedling cells. The hydroxylated metabolites were able to concentrate in the cells very rapidly and were unable to diffuse freely into the external medium. As a consequence, this process facilitated the penetration of large quantities of atrazine which became rapidly hydroxylated, allowing therefore the passive penetration of atrazine to be further improved, since the concentration C₁ in the receiver compartment was always close to zero. The passive transfer of atrazine, following Fick's law: dq/dt=-Pa (C₀–C₁), was therefore optimized. © 1997 SCI.     

Variation among seven genotypes of Lycopersicon esculentum and 36 accessions of L. hirsutum for interspecific crossability

To improve the efficiency of introgressing genes from Lycopersicon hirsutum (H) into L. esculentum (E), environmental and genetic variation for the number of progeny per fruit from E × H crosses was quantified. Over three dates in a year, 36 H accessions were crossed to seven E accessions in a greenhouse. The proportion of total variation for the number of E × H progeny per fruit due to environment (dates, location, and error), H accession, E accession, interactions between E and H, and interactions between accessions and environments was 0.42, 0.26, 0.12, 0.11, and 0.09, respectively. Sampling greater numbers of fruit on a single date improved the efficiency of recovering progeny more than increased sampling over time. The specific combination of E and H parents can profoundly affect the number of E × H progeny recovered and therefore the efficiency of gene introgression. Accessions of H from the southern edge of the species' natural geographic range generally yielded few to zero progeny per fruit in crosses with E. In contrast to the southern H accessions, most northern accessions produced greater than 40 E × H progeny per fruit. Most genes within H should be readily accessible for tomato breeding but genes that are found only in southern H accessions may be challenging to introgress. This revised version was published online in July 2006 with corrections to the Cover Date.     

Optimization of virulence functions through glucosylation of Shigella LPS

Shigella, the leading cause of bacillary dysentery, uses a type III secretion system (TTSS) to inject proteins into human cells, leading to bacterial invasion and a vigorous inflammatory response. The bacterium is protected against the response by the O antigen of lipopolysaccharide (LPS) on its surface. We show that bacteriophage-encoded glucosylation of Shigella O antigen, the basis of different serotypes, shortens the LPS molecule by around half. This enhances TTSS function without compromising the protective properties of the LPS. Thus, LPS glucosylation promotes bacterial invasion and evasion of innate immunity, which may have contributed to the emergence of serotype diversity in Shigella.