Search Results (3)

This study was conducted to investigate the effects of different proteases alone or in combination on protein digestibility of broilers. In vitro, the properties of four proteases in broilers, including acidic protease (AcP), alkaline protease (AlP), neutral protease (NeP) and keratinase (Ker), on endogenous protease activity and their effects on protein digestibility of common ingredients in broiler diets were investigated using a gut-mimicking model. In vivo, 640 1-day-old male broilers were randomly divided into 8 groups of 10 with 8 replicates of 10 birds per replicate cage. Eight dietary treatments included a corn–soybean meal basal diet (control), and the basal diet with 1.6 U AcP/g, 0.8 U NeP/g, 0.8 U AlP/g, 0.4 U Ker/g, 1.6 U AcP/g + 0.8 U NeP/g, 1.6 U AcP/g + 0.8 U AlP/g, or 1.6 U AcP/g + 0.4 U Ker/g added. The experiment lasted for 31 days. The results showed that the optimum pH values of AcP, NeP, AlP and Ker were 3.0, 9.0, 11.0 and 11.0 in vitro, respectively. Ker recovery proportion was 37.68% at pH 3.3–6.2. AcP alone or in combination with NeP, AlP or Ker increased in vitro crude protein digestibility (IVCPD) and decreased ileal apparent digestibility of crude protein in 31-day-old broilers (p < 0.05). All protease supplementation reduced the ileal apparent digestibility of amino acids compared to the control (p < 0.05). Acidic protease had a positive effect on trypsin and chymotrypsin activities, while AlP and Ker showed a negative effect. In vivo, average daily gain and average daily feed intake were significantly (p < 0.05) increased in broiler diets supplemented with AcP compared to the control group. When adding exogenous proteases to broiler diets, their sensitivity to digestive pH and their negative effects on endogenous protease activity, dosage and combination effects should be taken into account. In addition, the properties and dosage of proteases and the protein level in the feed should be considered. Full article

The study aimed to compare the in vitro biocompatibility of pectin gels formed by different cross-linking cations. Hydrogel beads named CaPG, ZnPG, FePG, and AlPG were prepared from 4% solutions of apple pectin using ionotropic gelling with CaCl₂, ZnCl₂, FeCl₃, and AlCl₃, respectively. Cations influenced the gel strength of the wet gel beads in the following order (least strong) Ca²⁺ < Zn²⁺ < Fe³⁺~Al³⁺ (most strong). The swelling degree of the CaPG beads after 24 h of incubation in the RPMI-1640 medium was 104%, whereas the ZnPG, FePG, and AlPG beads swelled by 76, 108, and 134%, respectively. The strength of the pectin gel decreased significantly after incubation in the RPMI-1640 medium for 24 h, regardless of the cross-linking cation, although the FePG beads remained the strongest. All the pectin beads adsorbed serum proteins to a low degree, however the serum protein adsorption by the ZnPG and FePG beads (1.46 ± 0.87 and 1.35 ± 0.19 µg/mm²) was more than the CaPG and AlPG beads (0.31 ± 0.36 and 0.44 ± 0.25 µg/mm²). All the pectin beads reduced the production of TNF-α and IL-10 by hPBMCs in response to LPS stimulation. The IL-1β response of cells to LPS was significantly reduced by the CaPG, ZnPG, and FePG beads, whereas the AlPG beads enhanced it twofold. The CaPG, FePG, and AlPG beads had no cytotoxicity. The viability of hPBMCs and human fibroblasts incubated with ZnPG beads was 5.3 and 7.2%, respectively. Thus, the use of different cross-linking cations changed the properties of the pectin gel, which is important for biocompatibility. Full article

It is important to understand residential energy use as it is a large energy consumption sector and the potential for change is of great importance for global energy sustainability. A large energy-saving potential and emission reduction potential can be achieved, among others, by understanding energy consumption patterns in more detail. However, existing studies show that it requires many input parameters or disaggregated individual end-uses input data to generate the load profiles. Therefore, we have developed a simplified approach, called weighted proportion (Wepro) model, to synthesise the residential electricity load profile by proportionally matching the city’s main characteristics: Age group, labour force and gender structure with the representative households profiles provided in the load profile generator. The findings indicate that the synthetic load profiles can represent the local electricity consumption characteristics in the case city of Amsterdam based on time variation analyses. The approach is in particular advantageous to tackle the drawbacks of the existing studies and the standard load model used by the utilities. Furthermore, the model is found to be more efficient in the computational process of the residential sector’s load profiles, given the number of households in the city that is represented in the local profile. Full article