Evaluation of the in vitro and in vivo efficiency of in-feed bacteriophage cocktail application to control Salmonella Typhimurium and Salmonella Enteritidis infection in broiler chicks.

RESEARCH HIGHLIGHTS: Bacteriophage (BP) cocktail was partially resistant to different temperatures and pH values.The BP cocktail showed lytic effects on different Salmonella isolates.The BP cocktail reduced Salmonella colonization in the internal organs of broilers.

The effect of heavy metals on the nutritional value of Alfalfa: comparison of nutrients and heavy metals of Alfalfa (Medicago sativa) in industrial and non-industrial areas.

The aim of this study is to compare the nutritional value of Alfalfa and accumulation of heavy metals in the farms near and far from the industrial regions. Three regions were considered located at 2, 32 and 65 km distances from an industrial region, and the nutrient content of the Alfalfa including crude protein, crude fiber, crude fat, nitrogen-free extract, and Ash as well as soil and plant heavy metals was determined. The results showed no significant difference in the value of nutrients in the three regions except nitrogen-free extract (mainly starch and sugars). A positive correlation was observed between nitrogen-free extract and lead, chromium, and arsenic (p ≤ 0.05). In addition, the highest accumulations of heavy metals such as arsenic, chromium, lead and cadmium were found in soil and Alfalfa produced at 2 km distance from the industrial area. The lead and cadmium concentrations were higher than the maximum allowable agricultural soil concentration in the areas near industrial region; the accumulation of these metals in the Alfalfa was however lower than the cattle and plant risk levels. The distribution of heavy metals in the Alfalfa cultivated in these three areas (zinc > copper > lead > chromium > arsenic > cadmium) did not coincide with the average of these metals in the soils (lead > zinc > chromium > copper > cadmium > arsenic). The positive correlation was also recorded between electrical conductivity of agricultural soils and copper, lead, chromium and arsenic content of Alfalfa. The highest translocation factors of arsenic, chromium and lead elements were detected in industrial areas. For copper and zinc, the highest translocation factor was found in non- industrial areas. The results of this study can be applied as an important control program in different areas.

Simultaneous optimization of power and duration of radio-frequency pulse in PARACEST MRI.

Chemical exchange saturation transfer (CEST) MRI is increasingly used to probe mobile proteins and microenvironment properties, and shows great promise for tumor and stroke diagnosis. The CEST effect is complex and depends not only on the CEST agent concentration, exchange rates, the characteristic of the magnetization transfer (MT), and the relaxation properties of the tissue, but also varies with the experimental conditions such as radio-frequency (RF) pulse power and duration. The RF pulse is one of the most important factors that promote the CEST effect for biological properties such as pH, temperature and protein content, especially for contrast agents with intermediate to fast exchange rates. The CEST effect is susceptible to the RF duration and power. The present study aims at determining the optimal power and the corresponding optimal duration (that maximize the CEST effect) using an off-resonance scheme through a new definition of the CEST effect. This definition is formulated by solving the Bloch-McConnell equation through the R1ρ method (based on the eigenspace solution) for both of the MT and CEST effects as well as their interactions. The proposed formulations of the optimal RF pulse power and duration are the first formulations in which the MT effect is considered. The extracted optimal RF pulse duration and power are compared with those of the MTR asymmetry model in two- and three-pool systems, using synthetic data that are similar to the muscle tissue. To validate them further, the formulations are compared with the empirical formulation of the CEST effect and other findings of the previous researches. By extending our formulations, the optimal power and the corresponding optimal duration (in the biological systems with many chemical exchange sites) can be determined.

Effects of diets containing alfalfa hay or barley flour mixed alfalfa silage on feeding behavior, productivity, rumen fermentation and blood metabolites in lactating cows.

The effects of barley flour on the fermentation parameters of alfalfa silage and on the productivity of dairy cows were investigated. Alfalfa forage was ensiled either with or without barley flour. Barley flour was soaked in water for 24 h before being mixed with alfalfa (12 kg: 100 kg dry matter bases) at ensiling. Eighteen multi-parous cows were assigned to three equal treatment groups using a completely randomized design. Three isocaloric and isonitrogenous total mixed rations containing alfalfa hay, ordinary alfalfa silage or barley flour mixed alfalfa silage were then prepared. The concentrations of ammonia nitrogen, acetic acid and butyric acid were lower in barley flour mixed alfalfa silage compared to that in ordinary alfalfa silage but the concentration of lactic acid was lower in the ordinary alfalfa silage. Feeding behavior, milk yield and composition, ruminal fermentation and blood metabolites were measured. Although dry matter intake and milk production were not affected, the effect of preparation of alfalfa influenced feeding behavior and rumen fermentation parameters. Cows on alfalfa silage diets spent longer ruminating compared to those fed alfalfa hay. The ruminal ammonia nitrogen and blood urea were affected by ensiling (alfalfa hay versus alfalfa silages) while both parameters were lower in cows fed on barley flour mixed alfalfa silage than those fed on ordinary silage. Although similar blood glucose was recorded for cows fed on alfalfa silages, it was higher in cows fed on alfalfa hay. It is concluded that the addition of barely flour when making alfalfa silage may improve both the fermentation process during ensilage and the ruminal ammonia nitrogen utilization with no significant effects on productivity.

Relative fibrolytic activities of anaerobic rumen fungi on untreated and sodium hydroxide treated barley straw in in vitro culture.

The fibrolytic activities of rumen fungi were studied in terms of dry matter loss, plant cell wall degradation and enzyme (cellulase and xylanase) activities, when grown in vitro on either untreated or sodium hydroxide treated stems of barley straw over a 12 day period. Changes in fungal growth, development and overall biomass were followed using chitin assay and scanning electron microscopy. Treatment with sodium hydroxide resulted in a decrease in the NDF content together with the disruption of cuticle and the loosening and separation of the plant cells within the straw fragments. The enzyme activities of the anaerobic fungi have a high positive correlation (R(2)=0.99) with their biomass concentration assessed by chitin assay indicating that chitin is a valuable index for the estimation of the fungal biomass in vitro. The anaerobic fungi produced very extensive rhizoidal systems in these in vitro cultures. After incubation with rumen fungi, dry matter losses were, respectively, 35% and 38% for the untreated and treated straw samples and the overall fungal biomass, determined by chitin assay, was significantly higher in the treated samples. In vitro degradation of cellulose and hemicellulose was also higher in the treated than that of untreated cultures. Although, comparatively, xylanase activity was higher than that of cellulase, the cellulose fraction of the straw was degraded more than hemicellulose in both treated and untreated straw.

Methods for the isolation, culture and assessment of the status of anaerobic rumen chytrids in both in vitro and in vivo systems.

Anaerobic fungi were isolated from both the rumen and faeces of nine sheep and a cow. A reliable and simple method for the isolation of anaerobic fungi using 24 h rumen incubated milled straw as the inoculum source was developed. We also evaluate the use of chitin measurements as an assay of rumen fungal biomass. Chitin levels were determined from various sample sources (milled barley straw used as the fungal culture substrate in vitro; plant particulate digests from the rumen (PLP) and centrifuged strained rumen fluid (CSRF) using both HPLC and colorimetric methods. Both methods were highly correlated and consequently the simpler colorimetric method was adopted for subsequent studies. There was also a high degree of correlation between anaerobic fungal cellulase activities with the assayed chitin content of milled barley straw cultures over 12 d of an in vitro experiment. The colorimetric chitin assay protocol was then used to assess the diurnal variation and abundance of rumen fungi in in vivo assays. We assessed the distribution of chitin (mg g(-1) dry matter) in various fractions of the strained rumen fluid (SRF) and PLP samples from the rumen of sheep. Chitin was detected in all fractions of strained rumen fluid but the main source of chitin in the samples may be attributed to the fungal biomass. We did not detect any significant differences in chitin levels over a 24 h sampling period. Finally, an SEM study on subsamples of milled straw and plant particulate matter used in the chitin assays, revealed that the pattern of the fungal development on substrate material differs from the culture medium to the rumen.

Distribution and estimation of anaerobic zoosporic fungi along the digestive tracts of sheep.

The status of anaerobic zoosporic (Chytridiomycota) fungi along the entire digestive tract of sheep was assessed both analytically and microscopically. Digest samples were taken from different segments of the digestive tracts of three newly killed sheep that previously had been used in experimental dietary studies. These digest samples were tested for the presence of rumen fungi by assessing the recovery of live fungi from the samples, direct observation of digested plant remains under the scanning electron microscope (SEM), and using a chitin assay as an estimation of fungal biomass. Live anaerobic fungi were recovered from the abomasum, small and large intestine, caecum and faeces of sheep, but not from the digest samples of rumen and omasum. However, SEM examination of the samples confirmed the presence of fungal structures from all of these organs. In the large intestine and caecum samples the observed sporangial structures were rounded and showed conspicuous surface pitting. Results of the chitin assay indicated that the anaerobic fungi might account for up to 20% of the total microbial biomass in the rumen of sheep. The results of this study support the view that anaerobic fungi may be present as a resistant stage in the lower reaches of the digestive tract.