Effects of hemp seed and flaxseed on enzyme activity in the broiler chicken digestive tract.

The activity of enzymes in the digestive tract is an important parameter for appropriate digestive tract function. Feed mixtures can be adjusted to support enzymatic activity in different parts of the digestive tract. Flaxseed and hemp seed are commodities and significant sources of nutrition, and their addition to feed could change enzymatic activity in the digestive tract and improve nutritional intake. The aim of this study was to determine the effects of flaxseed, hemp seed and a combination of both on basic enzymes in the polysaccharidase group, such as amylase, cellulase, pectinase, xylanase and inulinase; basic enzymes in the disaccharidase group, including maltase, invertase and lactase; proteinases and lipases in the digestive tract of broiler chickens. During the experiment, the control group was fed a diet without flaxseed or hemp seed. The diet of the second group contained 80 g/kg flaxseed, the diet of the third group contained 40 g/kg hemp seed, and the diets of the fourth to sixth groups contained 80 and 30 g/kg, 80 and 40 g/kg and 80 and 50 g/kg flaxseed and hemp seed, respectively. Enzyme activity was found to depend on the location in the digestive tract and the composition of the feed mixture (P < 0.05). Most enzymatic conversion occurs in the ileum, where the addition of flaxseed and hemp seed to the diet increased most enzyme activities, namely, amylase, cellulase, pectinase, xylanase, maltase, invertase, proteinase and lipase activities. The highest values of enzyme activity were found in groups IV-VI fed a combination of flaxseed and hempseed, especially in chickens fed diet VI (flaxseed and hemp seed at 80 and 50 g/kg). Growth performance results confirmed the enzyme activity results, as the weights of the chickens increased after the addition of flaxseed and/or hemp seed. The findings have economic implications, suggesting that feeding a diet with a combination of flaxseed and hemp seed is beneficial.

Dietary fumonisin may compromise the nutritive value of feed and distort copper and zinc digestibility and retention in weaned piglets.

Fumonisins (FUM) have been reported to impede gut functioning in pigs. However, investigations into the possible effect on mineral metabolism are limited. Thus, the trial studied the apparent total tract digestibility (ATTD) and retention of dietary nitrogen and minerals, intestinal architecture, digestive enzymes activity and heat-shock protein 70 (Hsp70) activity. Eighteen weaned piglets of 7 weeks old were assigned to three groups and their feed either contained 0, 15 or 30 mg FUM/kg for 21 days. ATTD and retention of dietary N and minerals were measured in a 5- day long balance trial between Day 17 and Day 21. The digestible and metabolisable energy (DE and ME) content of the feeds were also determined. The body weights, cumulative feed intake, relative organ weights, digestive enzymes activity and intestinal morphology were not affected (p > 0.05) by dietary treatments. The DE content was significantly lower (p < 0.05) when the feed contained 15 mg/kg FUM, but no statistically reliable treatment effect was confirmed for ME content. Dietary FUM significantly lowered (p < 0.05) the ATTD of Ca and P but not (p > 0.05) N, K, Mg and Na. The relative retention rate of N, Ca, P, K, Mg and Na in all groups were not impacted (p > 0.05) by treatments. The ATTD and relative retention of Cu and Zn were remarkably (p < 0.05) lower in piglets fed FUM-contaminated feed. In addition, the expression of Hsp70 activity in the liver was significantly elevated (p < 0.05) in the highest treatment group. These findings suggest that a dietary dose of 15 or 30 mg FUM/kg diet distorts the nutritive value of the mixed feed, results in poor ATTD and retention rates of Zn and Cu, and elevate Hsp70 activity in the liver without altering intestinal architecture or digestive enzymes' activity in weaned piglets.

Effect of housing system and feed restriction on meat quality of medium-growing chickens.

The aim of the study was to evaluate the differences in meat quality of 420 Hubbard JA757 cockerels in relation to the housing system (litter and mobile box) and level of mixed feed (ad libitum [AL], reducing the level by 20% [R20] and 30% [R30]). Three groups of chickens were housed in litter boxes for the entire fattening period (stocking density: 0.094 m2/bird). The other 3 groups were housed in litter boxes until 28 d of age and then relocated into mobile boxes (stocking density: 0.154 m2/bird) on pasture until the end of the experiment at 57 d of age. Restricted groups received a reduced diet level from 29th to 57th d of age. Feed mixture restriction increased the pasture vegetation intake of chickens from 2.63 to 3.50 (R20) and 3.94 g of dry matter/bird/d (R30). Restriction adversely affected the dressing percentage (P < 0.001) and breast yield (P < 0.001), while the leg yield (P < 0.001) was increased with increasing restriction levels. Meat of chickens housed in mobile boxes on a pasture showed lower cooking loss (P < 0.001) and higher redness and yellowness values in the skin (P = 0.030 and P = 0.026; respectively) and meat (P = 0.008 and P < 0.001; respectively). The fragile meat after cooking was observed in chickens reared on litter (P = 0.001). As the level of restriction increased, the number of muscle fibres (P = 0.001) increased, and their cross-sectional area (P = 0.001) and diameter (P = 0.002) decreased. The highest contents of lutein (P = 0.002) and zeaxanthin (P = 0.006) in breast muscle were found in chickens housed in mobile boxes and fed 80% and 70% AL. However, the concentrations of α- and γ-tocopherol (P = 0.006 and P = 0.003) were negatively affected by feed restriction. A 30% reduction in feed level in outdoor housed chickens led to a decrease in oxidative stability (P = 0.024). Feed restriction (R20) in chickens housed in mobile boxes significantly increased the n3 fatty acids content (P = 0.002) and h/H index (P = 0.005) and reduced the n6/n3 ratio (P < 0.001) and atherogenic (P < 0.001) and thrombogenic index (P = 0.003), which possess a health benefits for human. In addition, restriction of mixed feed decreased cholesterol content in breast meat (P = 0.042). It might be concluded that, in terms of meat quality, cereal diet restriction of 20% in medium-growing cockerels housed in mobile boxes on a pasture is beneficial. The higher level of restriction does not lead to further improvement in meat quality indicators.

Local inhomogeneities resolved by scanning probe techniques and their impact on local 2DEG formation in oxide heterostructures.

Lateral inhomogeneities in the formation of two-dimensional electron gases (2DEG) directly influence their electronic properties. Understanding their origin is an important factor for fundamental interpretations, as well as high quality devices. Here, we studied the local formation of the buried 2DEG at LaAlO3/SrTiO3 (LAO/STO) interfaces grown on STO (100) single crystals with partial TiO2 termination, utilizing in situ conductive atomic force microscopy (c-AFM) and scattering-type scanning near-field optical microscopy (s-SNOM). Using substrates with different degrees of chemical surface termination, we can link the resulting interface chemistry to an inhomogeneous 2DEG formation. In conductivity maps recorded by c-AFM, a significant lack of conductivity is observed at topographic features, indicative of a local SrO/AlO2 interface stacking order, while significant local conductivity can be probed in regions showing TiO2/LaO interface stacking order. These results could be corroborated by s-SNOM, showing a similar contrast distribution in the optical signal which can be linked to the local electronic properties of the material. The results are further complemented by low-temperature conductivity measurements, which show an increasing residual resistance at 5 K with increasing portion of insulating SrO-terminated areas. Therefore, we can correlate the macroscopic electrical behavior of our samples to their nanoscopic structure. Using proper parameters, 2DEG mapping can be carried out without any visible alteration of sample properties, proving c-AFM and s-SNOM to be viable and destruction-free techniques for the identification of local 2DEG formation. Furthermore, applying c-AFM and s-SNOM in this manner opens the exciting prospect to link macroscopic low-temperature transport to its nanoscopic origin.

Metabolic Effects of a Hydrophobic Alginate Derivative and Tetrahydrolipstatin in Rats Fed a Diet Supplemented with Palm Fat and Cholesterol.

The effects of octadecylamide of alginic acid (amidated alginate) and tetrahydrolipstatin on serum and hepatic cholesterol, and the faecal output of fat and sterols, were investigated in rats. Amidated alginate is a sorbent of lipids, tetrahydrolipstatin is an inhibitor of pancreatic lipase. Rats were fed diets containing cholesterol and palm fat at 10 and 70 g/kg, respectively. Palm fat was provided by coconut meal. Amidated alginate at 40 g/kg diet significantly decreased serum total cholesterol, low-density lipoprotein and hepatic cholesterol, and hepatic lipids and increased the faecal output of fat and coprostanol. Tetrahydrolipstatin at 300 mg/kg diet significantly decreased low-density lipoprotein cholesterol and hepatic lipids and increased the faecal output of fat. The intake of feed was not significantly influenced; however, the weight gains in rats fed amidated alginate were lower than in rats of the control group. Both amidated alginate and tetrahydrolipstatin modified the fatty acid profile in excreta lipids. Concentrations of saturated fatty acids were decreased and those of unsaturated fatty acids increased. Despite different modes of action, amidated alginate and tetrahydrolipstatin were equally efficient in removing the dietary fat from the body.

Tailoring grating strip widths for optimizing infrared absorption signals of an adsorbed molecular monolayer.

Metal structures with resonances in the mid-infrared spectral range enable an increased sensitivity for detecting molecular vibrational signals. 1D gold strip gratings have already proven potential in surface-enhanced infrared absorption (SEIRA) experiments, as grating resonances and local electric field enhancement can be spectrally tuned by changing the grating period. Here, we identify the grating strip width as another important design parameter, which is investigated for further optimization of molecular absorption signal enhancement in SEIRA experiments. Previous literature used gratings to increase light absorption in relatively thick polymer layers. Here, we demonstrate the capability of gold strip gratings fabricated on a CaF2 substrate to enhance the CH2 vibrational modes of a thiol-based monolayer of MHDA. An optimal choice of the strip width w = 1.33 µm enables a maximum vibrational signal enhancement factor of around 84, when normalized to microscopic GIR measurements of an MHDA monolayer on an extended gold surface. Numerical simulations demonstrate the broadband local field enhancement of gold strip gratings, which are suitable for enhancing multiple vibrational modes in a large hot-spot volume.

Nanoscale resolved infrared probing of crystal structure and of plasmon-phonon coupling.

We show that slight variations of a crystal lattice cause significant spectral modifications of phonon-polariton resonant near-field interaction between polar semiconductor crystals and a scanning metal tip. Exploiting the effect for near-field imaging a SiC polytype boundary, we establish infrared mapping of crystal structure and crystal defects at 20 nm spatial resolution (lambda/500). By spectroscopic probing of doped SiC polytypes, we find that phonon-polariton resonant near-field interaction is also sensitive to electronic properties due to plasmon-phonon coupling in the crystals.

Performance of visible and mid-infrared scattering-type near-field optical microscopes.

We describe the principles of two scattering-type near-field optical microscopes (s-SNOMs), one operating at 633 nm wavelength, the other at selectable wavelengths in the range 7.3-11.3 micro m, and compare the measurement experience. Both use interferometric detection of scattered radiation, and are therefore capable of amplitude and phase-contrast imaging. In this study both instruments use the same or even identical commercial probe tips, and measure a single, three-component, test sample. Our results show that the imaging process of s-SNOM is wavelength-independent, namely, that the resolution is determined by the properties of the tip only, and that the contrast is given by the complex refractive index of the sample, predictable from a simple, analytical model of tip-sample interaction. A novel, 'edge-darkening' artefact is described which may appear in s-SNOM and that is wavelength-independent.

Phonon-enhanced light matter interaction at the nanometre scale.

Optical near fields exist close to any illuminated object. They account for interesting effects such as enhanced pinhole transmission or enhanced Raman scattering enabling single-molecule spectroscopy. Also, they enable high-resolution (below 10 nm) optical microscopy. The plasmon-enhanced near-field coupling between metallic nanostructures opens new ways of designing optical properties and of controlling light on the nanometre scale. Here we study the strong enhancement of optical near-field coupling in the infrared by lattice vibrations (phonons) of polar dielectrics. We combine infrared spectroscopy with a near-field microscope that provides a confined field to probe the local interaction with a SiC sample. The phonon resonance occurs at 920 cm(-1). Within 20 cm(-1) of the resonance, the near-field signal increases 200-fold; on resonance, the signal exceeds by 20 times the value obtained with a gold sample. We find that phonon-enhanced near-field coupling is extremely sensitive to chemical and structural composition of polar samples, permitting nanometre-scale analysis of semiconductors and minerals. The excellent physical and chemical stability of SiC in particular may allow the design of nanometre-scale optical circuits for high-temperature and high-power operation.