Productive Performance of Broiler Chicks Fed Irradiated Diet

The aim of this study was to determine feasibility of Gamma irradiation in broiler chicks’ diet and scrutiny of productive performance of broiler due to gamma irradiated diets. There were 256 broiler chicks (male and female) from Arian strain. Experiment was statistically analyzed using balanced complete randomized design with four factors (including four irradiation doses: 0, 6.7, 7.7 and 8.7 Kilogray) and four replicates in each treatment. The results showed that there were significant (P≤0.05) difference in body weight gain and feed intake between control and irradiated groups. There was no significant (P>0.05) difference in feed conversion ratio (FCR) between irradiated and control groups. Statistical comparison for mortality rate indicated that there was no significant (P>0.05) difference between irradiated and control groups

Microstructure and tribological properties of as-cast and multi-pass friction stir processed Mg-0.5Zn-0.5Zr/SiC composite fabricated by stir casting technique

In this investigation, the Mg-0.5Zn-0.5Zr/4%SiC composite fabricated by the stir casting method was subjected to multi-pass friction stir processing (MFSP) to evaluate its microstructure, hardness, dry-sliding wear, and friction properties in comparison to those of the as-cast composite (ACC). Microstructural observations revealed the formation of a Mg matrix with average grain size (AGS) of 107 ± 12 μm, uneven dispersion (agglomeration) of SiC particles in the structure, and the formation of Zr-rich phase with the chemical composition of Zr:78.42, C:19.46, Mg:1.86, and Zn:0.26 wt%, ZrC, as well as some new formed carbide-based phases mostly propagated along the grain boundaries. On the other hand, the MFSP implementation led to a significant microstructural modification, i.e., in the optimum circumstance, the AGS and SiC particle size in the stir zone was reduced by 97.28 % (107–2.9 μm) and 67.69 % (21.33–6.89 μm), respectively, and the density of the composite increased from 1.669 to 1.774 gr/cm3. According to dry-sliding wear test results, applying FSP and increasing the pass number to three reduced the wear rate and coefficient of friction (COF) of the composites by about 45 % and 24 %, respectively, compared to those of ACC. The wear resistance enhancement was ascribed to wear mechanisms changing from delamination/adhesion/severe abrasion to mild abrasion wear, which stemmed from the formation of a stable O-rich tribolayer on the worn surface of FSPed samples

Enhancing the elevated temperatures tribological properties of Al–Mg2Si composites by in-situ addition of Ti-based intermetallics and hot working

Dry-sliding wear and friction behaviors of Al–15Mg2Si–5TiB2–4TiAl3 in-situ hybrid composites were evaluated at different temperatures (100–300 °C) and loads (10–60 N). The addition of TiB2 and TiAl3 particles enhanced the wear resistance. Moreover, the severe wear transition condition was changed from 300 °C to 10 N for the as-received Al–15Mg2Si composite to 300 °C - 60 N for the as-cast Al–15Mg2Si–5TiB2–4TiAl3 hybrid composite. This change was ascribed to the presence of thermostable particles and refined/modified Mg2Si particles via nucleation mechanism. Applying thermomechanical processing and hot deformation by the extrusion process necessitated higher loads and temperatures for this transition. Indeed, fragmentation and more homogeneous dispersion of reinforcements, higher hardness and toughness of composite due to grain refinement by dynamic recrystallization (DRX), reduction and closure of casting defects, and stability of tribolayer were recognized as leading reasons for replacing severe adhesive/plastic deformation wear with the abrasive mechanism. Accordingly, this study introduced an Al matrix hybrid composite with excellent performance at elevated temperatures

A Survey on the Gastrointestinal Parasites of Rabbit and Guinea Pig in a Laboratory Animal House

There is documented evidence that infection in laboratory animals can often influence the outcome of experiments. All infections, apparent or inapparent, are likely to increase biological variability. As a research project concerning the diversity and distribution of parasites of rabbit and guinea pig in a conventional laboratory animal house, about 87 rabbits (from 700 ) and 105 guinea pigs (from 1500 ) were selected randomly from a Research, Production & Breeding of Laboratory Animals Department. Samples were collected between 19.02.2010 and 20.05.2011. The samples and animals were examined by dissection and flotation methods. In this study only one species of nematodes (Passalorus ambiguus: 6.9%); one species of protozoa (Eimeria spp.: 21.8%) in rabbits and one species of nematodes (Paraspidodera Uncinata: 24.7%); one species of protozoa (Balantidium coli: 11.4%) in guinea pigs were identified. However, there was not any cestodes or trematodes identified from this group of laboratory animals

Food web effects of titanium dioxide nanoparticles in an outdoor freshwater mesocosm experiment

<p>Over the course of 78 days, nine outdoor mesocosms, each with 1350 L capacity, were situated on a pontoon platform in the middle of a lake and exposed to 0 μg L⁻¹ TiO₂, 25 μg L⁻¹ TiO₂ or 250 μg L⁻¹ TiO₂ nanoparticles in the form of E171 TiO₂ human food additive five times a week. Mesocosms were inoculated with sediment, phytoplankton, zooplankton, macroinvertebrates, macrophytes and fish before exposure, ensuring a complete food web. Physicochemical parameters of the water, nutrient concentrations, and biomass of the taxa were monitored. Concentrations of 25 μg L⁻¹ TiO₂ and 250 μg L⁻¹ TiO₂ caused a reduction in available soluble reactive phosphorus in the mesocosms by 15 and 23%, respectively, but not in the amount of total phosphorus. The biomass of Rotifera was significantly reduced by 32 and 57% in the TiO₂ 25 μg L⁻¹ and TiO₂ 250 μg L⁻¹ treatments, respectively, when compared to the control; however, the biomass of the other monitored groups—Cladocera, Copepoda, phytoplankton, macrophytes, chironomids and fish—remained unaffected. In conclusion, environmentally relevant concentrations of TiO₂ nanoparticles may negatively affect certain parameters and taxa of the freshwater lentic aquatic ecosystem. However, these negative effects are not significant enough to affect the overall function of the ecosystem, as there were no cascade effects leading to a major change in its trophic state or primary production.</p