Xingzheng Li

Comparison of grain from corn rootworm resistant transgenic DAS-59122-7 maize with non-transgenic maize grain in a 90-day feeding study in Sprague-Dawley rats

DAS-59122-7 (59122) is a transgenic maize (Zea mays L.) that contains genes encoding Cry34Ab1 and Cry35Ab1 proteins from Bacillus thuringiensis Berliner strain 149B1 and phosphinothricin acetyltransferase (PAT) protein from Streptomyces viridochromogenes. Expression of these proteins in planta confers resistance to corn rootworms and other Coleopteran parasites and tolerance to herbicides containing glufosinate ammonium, respectively. In the current study, processed flours from 59122 maize grain or its near isogenic control line (091) were used at two concentrations (50% and 70% wt/wt) to produce diets that were fed to rats for 90 days in accordance with Chinese toxicology guidelines (GB15193.13-2003). A commercial AIN93G diet was used as an additional negative control. No significant differences in body weight and feed utilization were observed between rats consuming diets formulated with 59122 and 091 Control corn. Statistical differences (p<0.05) were observed in certain hematology and serum chemistry response variables between rats consuming diets formulated with 59122 or 091 Control flour compared to AIN93G diet. However, the mean value of these response variables in the 59122 groups were not statistically different from those observed in diets formulated with corresponding high and low concentrations of the flour from the 091 Control maize grain. Therefore, the statistical differences were considered to be related to consumption of diets containing high concentrations of maize flour (compared to AIN93G diets) regardless of source rather than to consumption of flour from 59122 maize grain. The results from this study demonstrated that 59122 maize grain is as safe as non-transgenic maize grain.

Protective effect of Bacillus subtilis ANSB060 on egg quality, biochemical and histopathological changes in layers exposed to aflatoxin B1

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.

Comparative Physicochemical Properties and Structure of Rice Containing the sck+cryIAc Genes and Its Nontransgenic Counterpart

The physicochemical properties and structure of an insect-resistant rice, Liangyou Kefeng Nr. 6 (IRR), containing the sck and cryIAc genes were compared with those of its nontransgenic counterpart designated as Liangyou 2186 (control), considering their key role in determining commercial value. Basically the appearance of IRR was not affected in terms of size and shape after foreign gene transformation but improved with lower chalkiness. The milling yield of IRR with lower chalkiness was higher measured by head rice yield compared with its parental control. The differences in appearance and milling quality were confirmed by the structure of raw rice grain by scanning electron microscopy (SEM). Slight differences were observed in pasting properties and textural quality determined by rapid viscosity analyzer and texture analyzer which was in agreement with the result of the structure of cooked rice grain by SEM. The above differences might be as a result of a positional effect of T-DNA insertion. On the whole, the appearance, milling quality, and eating quality of IRR were not adversely affected by transgenes, which will facilitate its acceptance by the consumer after commercialization.

Impact of cuticle quality and eggshell thickness on egg antibacterial efficiency

ABSTRACT The cuticle is the first barrier against bacterial trans‐shell penetration. To evaluate the cuticle quality among different colored eggshells, an efficient and reliable method is proposed in this paper on the basis of the opacity theory. It is shown that the Spearmans rank correlation coefficients between the proposed opacity method and the reported reflectance and &Dgr;E*ab methods are all more than 0.90 in measuring the cuticle deposition for the same breed eggs, indicating that the result measured by the opacity method is credible. In addition, the validity of opacity method is also verified by the Escherichia coli penetration experiments performed on the eggs of Dwarf Layer (tinted‐shelled), Hy‐Line Brown (brown‐shelled), and White Leghorn (white‐shelled) birds. Results show that the Dwarf Layer eggs, with the thickest cuticle deposition, have the lowest bacterial penetration ratio than the eggs of the other 2 investigated breeds. We found that eggshell thickness is another important factor influencing bacterial penetration apart from the cuticle. Therefore, enhancing cuticle deposition and eggshell thickness would significantly improve the eggs antibacterial efficiency. It is found that the antibacterial efficiency will reach as high as 98% in such a case where the cuticle opacity is over 27.5% and the eggshell is thicker than 340 &mgr;m. No significant difference was found in pore density between the penetrated and non‐penetrated eggs. Moreover, according to the data for 3 regions of the penetrated eggs, we found that the sharp end shows the highest proportion of bacterial contamination compared with the blunt end and equator. The cuticle quality at equator shows a strong positive correlation between the blunt and sharp end (r2 = 0.8 and 0.7, respectively, P < 0.05). The cuticle at the equator can be selected as an indicator for cuticle breeding to improve the cuticle quality at the blunt and sharp end simultaneously. These results are of significance for the improvement of egg quality and safety in modern commercial breeding.

Fishy Odor and TMA Content Levels in Duck Egg Yolks: Fishy odor of duck eggs…

The differences between the trimethylamine (TMA) content levels in duck and chicken egg yolks under normal dietary conditions were compared. Moreover, the association between the polymorphisms of the duck FMO3 gene and TMA content levels in duck egg yolks was analyzed. Then, to detect the mutations associated with the fish-flavor trait, duck populations were selected for a high-choline diet experiment, which was followed by full-length sequencing of the FMO3 exons. The results showed that the TMA content levels in duck eggs (3.60 μg/g) were significantly higher than those in chicken eggs (2.35 μg/g) under normal dietary conditions (P < 0.01). With regard to the high-choline diet, the average TMA content levels in duck egg yolks (9.21 μg/g; P < 0.01) increased significantly. Furthermore, 5 SNPs reported in Ensembl database were detected in duck FMO3 exons. However, no mutation loci were found to be significantly associated with the TMA content levels in duck egg yolks. Besides, duck liver FMO3 mRNA expression levels were not associated with the TMA content levels. The results indicated that excessive TMA deposition in duck eggs is one of main factors causing the fishy odor in duck eggs, and the addition of choline in the ducks diets was responsible for inducing an increase in the TMA content levels in duck eggs.nnnPRACTICAL APPLICATIONnOur study can help to diminish the fishy taste in duck eggs by reducing the amount of supplemented choline. Furthermore, this study laid a solid foundation for revealing the genetic factors involved in the fishy odor in duck eggs.

The Distribution Characteristics and Applications for Maternal Cells on Chicken Egg Vitelline Membrane

The major components of vitelline membrane (VM) are ovomucin, VM outer (VMO) I and VMO II. At present, the distribution pattern of maternal cells on the VM has not been described in detail. In this study, the existence and distribution characteristics of maternal cells on VM were observed. There were more than 3.2u2009×u2009105 somatic cells on VM, which were uneven distributed. The calcein AM/PI staining of the maternal cells on the VM showed that the cells’ viability changed with the freshness of the eggs, and that the maternal cells gradually underwent apoptosis and became degraded. The results of morphology of different tissues indicated that the most of maternal cells on the VM were granulosa cells. Moreover, the karyotype of the cultured granulosa cells, which is the main source of cells on VM, were identified as the normal diploid karyotype of chicken. Furthermore, the VM DNA extracted from chickens and quails, which represent the eggs of different size, was adequate for further genetic analysis. The VM DNA was easily accessible and relatively constant, without cross-contamination. Therefore, the VM DNA could potentially be applied for the molecular traceability between eggs and chickens, and be beneficial in avian ecology research studies.

Salmonella Contamination in Layer Farms of Different Scales in China: Detection and ERIC-PCR Analysis

Salmonella is the most common cause of foodborne illnesses worldwide. Poultry eggs are a major contamination source of Salmonella. The prevalence of Salmonella has been effectively reduced since a series of measures were taken to reduce contamination in egg-laying houses. In the present study, 1,512 environmental samples obtained from layer farms of different production scales were screened in a voluntary Salmonella survey study. Contaminations were detected using a PCR method. Genetic relationships among Salmonella samples were specified using molecular typing by enterobacterial repetitive intergenic consensus (ERIC)-PCR. The survey results showed that two layer farms, located in the Shandong and Hebei provinces, were contaminated with Salmonella. Thirty-one samples from these two farms, including feed, drinking nipples, egg collection belt, air inlets and outlets, air, overshoes, and eggshells, were identified as Salmonella-positive. It was observed that certain samples within the henhouses as well as in the egg collecting areas showed relatively high genetic similarities. The survey conclusively revealed minor Salmonella contamination in northern China. Moreover, various areas within the layer farms were identified as part of the propagation chain of Salmonella. Furthermore, evidence of cross-contamination of Salmonella was found in the laying houses and egg collection areas, even between these two regions. Therefore, it is necessary to establish routine Salmonella detection and subsequent environmental control measures in order to decrease the prevalence of Salmonella.

Salmonella Enteritidis in Layer Farms of Different Sizes Located in Northern China: On-Farm Sampling and Detection by the PCR Method

Salmonella enterica subspecies enterica serotype Enteritidis (SE) has caused foodborne infections over decades. It is transmitted mainly from contaminated eggs to humans. SE is commonly present in layer houses, and closely interacts with environmental factors. The objective of the present study was to develop a viable PCR method to identify SE in environmental samples collected in layer farms of different sizes, and to evaluate SE contamination status in four main egg-production provinces of northern China. After specificity retrieval using PrimerBLAST against the NCBI database, three SE specific oligonucleotide primers were selected as candidate primers. The primers targeting Prot6e gene were adopted and primers targeting Sdf I were also selected to validate the results, after testing eight different types of pooled poultry environmental samples (overshoe, air, drinking nipple, feed, egg collection belt, eggshell, air inlet, and air outlet) by PCR. A PCR detection limit of 1 CFU/mL was determined using cell lysates from pure cultures. Testing time was less than 48 h. On-farm samples were collected from two layer farm sizes (one housing more than 50,000 layers, and the other, less than 50,000 layers) in each province. The applied PCR method was shown to be simple, inexpensive and effective for screening SE in a large amount of farm samples. The study identified only one SE-positive farm, which a large farm and where nine samples were found to be contaminated with SE: drinking nipples (3), egg collection belt (1), air inlet (1), air (1), overshoe (1) and eggshell (2).