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The use of cultivar mixtures to control foliar fungal diseases is well documented for windborne diseases, but remains controversial for splash-dispersed diseases. To try to improve this strategy, a cultivar mixture was designed consisting of two wheat cultivars with contrasted resistance to Mycosphaerella graminicola, responsible for the rainborne disease septoria tritici blotch ( STB), in a 1:3 susceptible:resistant ratio rather than the 1:1 ratio commonly used in previous studies. The impact of natural STB epidemics in this cultivar mixture was studied in field experiments over 4 years. Weekly assessments of the number of sporulating lesions, pycnidial leaf area and green leaf area were carried out on the susceptible cultivar. In years with sufficient STB pressure, disease impacts on the susceptible cultivar in the mixture were always significantly lower than in the pure stand (e.g. 42% reduction of pycnidial leaf area for the three upper leaves in 2008 and 41% in 2009). In years with low STB pressure (2010 and 2011), a reduction of disease impacts was also shown but was not always significant. After major rainfall events, the number of sporulating lesions observed on the susceptible cultivar after one latent period was reduced on average by 45% in the mixture compared to the pure stand. All the measurements showed that a susceptible cultivar was consistently protected, at least moderately, in a mixture under low to moderate STB pressure. Therefore, the results prove that the design of an efficient cultivar mixture can include the control of STB, among other foliar diseases. [ABSTRACT FROM AUTHOR]

1. The objective of this experiment was to study two feeding methods, which could potentially act on the gut microflora, the structure and/or the function of the digestive tract and thereby improve the performance of broilers. 2. Four dietary treatments were studied: a negative control (wheat based) with no additives (C), a positive control with 0·01 g/kg avilamycin (AV), a treatment with 0·6 g/kg fructo-oligosaccharides (FOS) and a treatment with the same composition as treatment C but in which a part or all (400 g/kg) of the wheat was given as whole wheat and a concentrate supplement (WW). The measurements were: the performance from 0 to 6 weeks, the bacterial counts at 3 and 6 weeks, the digestive tract morphology and the activity of some intestinal enzymes at 3 weeks. 3. The birds given AV had better daily live weight gain (DLWG) and feed conversion ratio (FCR) compared to treatment C. The birds given FOS had a lower feed intake and a lower DLWG than the birds on treatment C but their FCR was significantly improved. WW resulted in a numerically lower feed intake and a significantly lower DLWG than treatment C. With AV, the number of aerobic mesophilic bacteria in the caeca was reduced at 3 weeks. With WW, gizzard and pancreas weights were greater and the surfaces of the ileal crypts were larger. An increased activity of leucine aminopeptidase (LAP) in the duodenum was found for treatments AV, FOS and WW. 4. In conclusion, in this study, treatments WW and FOS reduced DLWG, which may have been due to a lower feed intake during the whole period. With WW, the FCR was not affected, maybe because of both positive and negative effects on digestive tract (higher gizzard and pancreas development and LAP activity; larger crypts). However, FOS improved FCR, which may be partly explained by the higher LAP activity. [ABSTRACT FROM AUTHOR]

Puccinia striiformisf. sp.tritici(PST), a clonal basidiomycete causing yellow rust disease on wheat, has a long record of‘overcoming’ cultivar resistance introduced by breeders. Despite the long dispersal capacity of its spores, the French population ofPSTpresents a strong geographical structure, with the presence of a specific pathotype (array of avirulence genes) at high frequencies in the south of France. The genetic diversity underlying this differentiation was analysed by microsatellite and AFLP markers. A total of 213 French isolates belonging to 10 pathotypes collected over a 15-year period were investigated. For each of the 12 microsatellites used, polymorphism resulted from a unique allelic variant associated to the south-specific pathotype. This pathotype was characterized by 40 specific markers over the total of 63 polymorphims detected using 15 AFLP primer combinations. Phylogeographical analysis indicated a strictly clonal structure of the population, and a strong genomic divergence between the northern population and a south-specific clone. Both virulence and molecular data show that the northern French population belongs to the northwestern European population, whereas the southern clone is most likely related to a Mediterranean population, the two subpopulations resulting from the ancient divergence of two clonal lineages. While the virulence complexity in the northern population may be explained by the successive introduction of corresponding resistance genes in cultivars, the maintenance of a simple virulence type in southern France, despite gene flow between the two populations, may be explained in terms of host cultivars repartition and local adaptation to specific host or climatic conditions. [ABSTRACT FROM AUTHOR]

Studies the effects of whole wheat added to pelleted protein on digestive tract of broiler chickens. Pepsin activity in proventriculus in whole wheat-fed chickens; Evidences for increase in chemical and physical functionality of upper part of digestive tract due to whole grain feeding.

Abstract: The objective of the current study was to investigate the impact of including whole wheat in broiler diets on the development of the digestive tract. Chickens were fed a standard feed containing 400g ground wheat/kg or the same diet with a part of the wheat given separately as whole grains that increased progressively from 200g/kg at 8d to 400g/kg at 22d. Every week, from 16 to 44d, growth performance, modifications of the size of the digestive tract organs and intestinal enzyme activities were investigated. Morphology of villi and crypts in the small intestinal segments (duodenum, jejunum, ileum) were analyzed at 23 and 44d. Microbacterial counts were performed in jejunal, ileal and caecal contents weekly from 16 to 44d. During the adaptation period from 8 to 15d, the birds fed the whole wheat diet had lower feed intake and lower weight gain. Thereafter, they showed improved growth performance so that by the end of the experiment, they had higher body weight compared to the standard-fed birds, 2430±29 versus 2331±36g. Higher relative weights of gizzard (+26%) and pancreas (+12%) were observed from 16 to 44d for whole wheat-fed birds compared to standard-fed birds. No differences in relative size of the different intestinal segments were observed, except that the jejunum was shorter. Increased villus to crypt length and surface ratios were observed at 23d in the duodenum of whole wheat-fed birds, with no differences in morphometry between groups thereafter. Alkaline phosphatase activity was higher from 16 to 44d in the duodenum and jejunum of whole wheat-fed birds. However, the activities of the digestive enzymes, leucine aminopeptidase and maltase, were similar between the two diets in the measured intestinal segments. A lower number of facultative anaerobic bacteria was found in the ileum of the whole wheat-fed birds, with no differences between treatments for Escherichia coli and for Lactobacillus counts. In the jejunum and the caeca, no differences in microflora counts were observed. The present results showed that feeding whole grains to broilers led mainly to modifications in the upper part of the digestive tract (gizzard, pancreas) and had little influence on the small and large intestine. [Copyright &y& Elsevier]

Abstract: An experiment was performed to assess the effect of feeding whole grain to poultry infected with coccidiosis. At the age of 7d, whole wheat and a pelleted protein concentrate (WP) were given to broiler chickens and compared to chickens fed a complete ground and pelleted diet (C). At 22d of age, each dietary treatment was divided into four groups, one uninfected control and the others inoculated each with one species of coccidia infecting different parts of the gut: Eimeria acervulina (duodenum), Eimeria maxima (jejunum and ileum) and Eimeria tenella (caeca). The effects of diets were assessed on growth performance until market-age, coccidial development criteria, and the faecal microflora. In uninfected birds, the WP diet led to a higher feed conversion efficiency from 7 to 28d of age and to a more beneficial microflora (higher counts of lactobacilli and lower counts of coliform bacteria) at 22d compared to the C diet. However, after experimental infection with each Eimeria species, bird performance was more affected with the WP diet than the C diet. During the acute phase of the disease, whole wheat led to a lower weight gain than the C diet: 17±7g/d versus 47±7g/d with E. acervulina (3–5dpost-inoculation, dPI), 16±11g/d versus 73±7g/d with E. maxima (4–7dPI), 13±12g/d versus 71±5g/d with E. tenella (4–6dPI). During the recovery phase, similar weight gains were found for both diets, whatever the Eimeria species. The decrease in serum coloration with E. maxima was higher in WP than C-fed birds. E. tenella led to a decrease in haematocrit only in WP-fed birds. The serum IgG antibody response to E. acervulina and E. tenella was higher in birds fed the WP than the C diet. The total oocyst excretion was similar between the two diets with E. acervulina, slightly higher with E. maxima (×1.5), and 10 times higher with E. tenella in WP- than C-fed birds. After coccidial infection, no effect on the microflora was observed in C-fed chickens, while in WP-fed chickens Escherichia coli counts were increased compared to their uninfected counterparts. Although whole wheat feeding appeared beneficial for uninfected chickens, after an experimental inoculation with coccidia this mode of feeding led to detrimental effects compared to the same diet with ground wheat. [Copyright &y& Elsevier]