Effects of Dietary Supplementation with Red Yeast (Sporidiobolus pararoseus) on Productive Performance, Egg Quality, and Duodenal Cell Proliferation of Laying Hens.

Nowadays, industrial poultry producers are more focused on the safety of their products, especially contaminants from feedstuffs such as mycotoxin and pesticides. The residue from animal production using antibiotic growth promoters (AGPs) may cause some problems with antimicrobial resistance in human and animals. Red yeast (Sporidiobolus pararoseus) has a cell wall consisting of ß-glucan and mannan-oligosaccharides and pigments from carotenoids that may be suitable for use as a substitute for AGPs. The objective was to evaluate the effects of red yeast in laying hen diets on productive performance, egg quality, and duodenal health. A total of 22-week-old laying hens (n = 480) were divided into five groups: control diet (CON), AGP at 4.5 g/kg and red yeast supplementation at 1.0 (RY1.0), 2.0 (RY2.0) and 4.0 g/kg (RY4.0) of diet. The results show that the AGP, RY2.0, and RY4.0 groups had significantly higher final body weight compared with the other groups (p < 0.001). The red yeast supplementation improved the egg shape index (p = 0.025), Haugh unit (p < 0.001), and yolk color (p = 0.037), and decreased yolk cholesterol (p < 0.001). Diet with red yeast supplementation improved villus height to crypt depth ratio and crypt cell proliferations. In conclusion, red yeast supplementation at 2.0 g/kg of diet can substitute AGP in layer diet.

The survival of pathogenic bacteria and plant growth promoting bacteria during mesophilic anaerobic digestion in full-scale biogas plants.

The introduction of biogas plants is a promising way to recycle organic wastes with renewable energy production and reducing greenhouse gas. Application of anaerobic digestate as a fertilizer reduces the consumption of chemical fertilizers. In this study, the survival of pathogenic bacteria and plant growth promoting bacteria (PGPB) in two full-scale biogas plants operated at mesophilic condition were investigated. Feedstock and anaerobic digestate samples were collected from biogas plants and bacteria load in samples were detected using standard dilution plate method. Pathogenic bacteria were reduced to not detected level through mesophilic digestion tank except for Campylobacter. However, it could be reduced by 98.7% through a sterilization tank. Bacillus was detected at 8.00 and 7.81 log10  CFU/g dry matter in anaerobic digestates, and it was also resistant to sterilization tank. Bacillus spp. is considered to be the safe bacteria that hold remarkable abilities for promoting plant growth. The results showed that treatment at biogas plants is effective to reduce pathogenic bacteria in dairy manure, and sterilization could further reduce the sanitary risks of pathogenic bacteria relating to anaerobic digestate application. Anaerobic digestates could also be utilized as bio-fertilizer as the high load of plant growth promoting bacteria.

Potential of anaerobic digestate of dairy manure in suppressing soil-borne plant disease.

Frequent use of pesticides to control soil-borne plant disease leads to environmental pollution and the development of pesticide resistance in phytopathogens. Soil amendment is considered to have the potential of suppressing plant disease because of its biological properties. However, information on anaerobic digestate is limited. In this study, potential of antagonistic activities of anaerobic digestate against phytopathogens were investigated by detecting the amounts of antagonistic bacteria (Bacillus and Pseudomonas) in anaerobic digestates of dairy manure. The results showed that anaerobic digestion increased the total amounts of Bacillus and Pseudomonas in digestate. Bacillus suppressed growth of phytopathogens, while Pseudomonas did not show any antagonistic activities. These results indicated that Bacillus was an effective antagonistic bacterium in digestate against phytopathogens. Furthermore, two selected isolates, B11 (Bacillus subtilis) and B59 (Bacillus licheniformis), were applied in field experiments and showed significant reduction in percent infection of potato late blight (Phytophthora infestans). These results demonstrate the benefits of digestate in suppressing soil-borne plant diseases caused by antagonistic bacteria.

Valorizing waste iron powder in biogas production: Hydrogen sulfide control and process performances.

Biogas is composed of different gases including hydrogen sulfide (H2S), which is a hazardous gas that damages pipes and generators in anaerobic digestion system. The objective of this study was to control H2S by waste iron powder produced by laser cutting machine in a steel and iron industry. Waste iron powder was mixed with dairy manure at a concentration between 2.0 and 20.0 g/L in batch experiments, while the concentration was varied between 1.0 and 4.0 g/L in bench experiment. In batch experiment, a reduction of up to 93% of H2S was observed at waste iron powder of 2.0 g/L (T1), while the reduction was of more than 99% at waste iron powder beyond 8.0 g/L (T4 âˆ¼ T6). The total sulfide concentration (ST) increased together with waste iron powder concentration and was fitted with a quadratic equation with a maximum ST of 208.0 mg/L at waste iron powder of 20.2 g/L. Waste iron powder did not have significant effect on methane yield in batch and bench experiments. However, hydrolysis rate constant was increased by almost 100%, while the lag-phase period was reduced to half in test digesters compared to that in control digester. In bench experiment, H2S concentration was reduced by 89% at 2.0 g/L, while 50% at 1.0 g/L. Therefore, waste iron powder was effectively removed H2S and did not affect negatively anaerobic digestion process.