The Mx gene is considered to confer positive antiviral responses to the orthomyxovirus in many organisms. In the chicken, 1 nonsynonymous single nucleotide polymorphism (G to A) at position 2,032 of Mx cDNA was demonstrated to confer positive antiviral activity in vitro to avian influenza virus in a previous study. In the current study, 15 Chinese native chicken breeds, 4 highly selected commercial lines, and the Red Jungle Fowl were selected to detect allele frequencies of the Mx mutation. The frequencies of the favorable allele A in native breeds were 0.7241 to 0.9554, which were much higher than those (0.0565 to 0.2742) found in the commercial populations. Whereas most native breeds were in Hardy-Weinberg equilibrium at this locus (P > 0.01), 3 out of 4 commercial populations were not in Hardy-Weinberg equilibrium (P < 0.01). Selection, environment, and negative correlations between production and disease resistant traits could contribute to highly skewed frequencies of the mutation among native breeds and commercial populations. The results suggested that further studies are needed with regard to the genetic resistance to avian influenza in different populations with various domestication background and selection history.

Bacillus subtilis ANSB060 from the fish gut had strong ability to detoxify aflatoxins. The aim of this research was to investigate the protective effect of B. subtilis ANSB060 (ANSB060) on egg quality and biochemical and histopathological changes of liver and kidney in laying hens when exposed to aflatoxin B(1). Treatments (C20, C40, and C60) were prepared by substituting corn contaminated by aflatoxin B(1) (AFB1) at different proportions (20, 40, and 60%) for normal corn in basic diets. The aflatoxin degradation enzyme (E) treatments (E20, E40, and E60) were mixed with the fermentation liquor of ANSB060 with C20, C40, and C60, respectively. The results showed that ANSB060 can improve the eggshell strength in E60 compared with C60 (P ≤ 0.05), and toxin reduced the content of total protein (in groups C20, C40, and C60) and albumin (in C20 and C40; P < 0.05) and heightened the activities of GPT (in C60) and GOT (in C40 and C60) in serum (P < 0.05). In the liver, AFB1 inhibited the activity of superoxide dismutase and glutathione peroxidase (C40 and C60; P < 0.05) and increased the content of malonaldehyde (in C40 and C60), which induced the damage in the liver and kidney as shown in the photomicrographs of hematoxylin and eosin-stained sections. The addition of ANSB060 can enhance the activity of antioxidant enzymes, and it recovered the protein synthesis in liver. Moreover, ANSB060 also ameliorated the damage of liver and kidney tissue and restored them to normal. Hence, ANSB060 had the ability to inhibit the damage induced by AFB1; it will have a great potential in industrial applications.

The Mx protein, which confers resistance to orthomyxovirus, has been detected in several organisms, and one nonsynonymous substitution (S631N) of the chicken Mx protein has been shown to affect resistant activities to the avian influenza virus in vitro. In the current study, the genomic sequence and polymorphism of the chicken Mx gene are reported. The full length of the chicken Mx gene spans about 21 kb, with 13 exons on chromosome 1 of the chicken genome. A total of 237 single nucleotide polymorphisms were found in the chicken Mx gene by comparison among 4 directly sequenced Mx genomic DNA sequences, and the reference sequence was inferred from the chicken genome project. The genomic diversity of the chicken Mx gene showed large variation in different regions, with the highest diversity in the 5' untranslated region and the lowest in the 3' untranslated region. The genomic structure and variation of sequences gathered here will allow an extensive analysis of the gene function with the aim of improving the antiviral resistance activities of chickens.

SummaryLong-term changes of soil nematode diversity and distribution patterns in replant peach orchard (RPO) and continuous-planting peach orchard (CPPO) were assessed to evaluate different effects on nematode community and function by RPO and CPPO, in relation to peach replant problem from the point of soil fauna. Observations were conducted on a silt loam soil, and soil sampling was performed four times through the growing season of peach trees in the period from 2006 to 2008 in Pinggu, Beijing. The result showed that RPO differed from CPPO by its higher abundance of plant feeding nematodes but lower abundance of bacterivore nematodes, as well as signifi cantly higher values of plant parasite index but lower nematode biodiversity. Obviously, the absolute abundance of Paratylenchus in RPO was higher than that in CPPO, which could be a key factor for the peach replant problems from the part of soil nematode. Nematode function indices and weighted nematode fauna profi le analysis were no signifi cantly different in the two peach ecosystems, but they represented an indication of high disturbance, N-enriched, bacterial decomposition pathway.