Association between Digesta pH, Body Weight, and Nutrient Utilization in Chickens of Different Body Weights and at Different Ages

Supplementation with liquid whey and ACIDAL® ML in drinking water affect gut pH and microflora and productive performance in laying hens

1. As the use of antibiotics as growth promoters has been banned in many regions, there has been an on-going search for possible alternative compounds, such as prebiotics and organic acids. 2. This study was conducted to investigate the influence of liquid whey (LW) and organic acid (ACIDAL® ML) supplementation on performance, eggs characteristics, gut pH and health status in laying hens. 3. Seven hundred and fifty, Isa Brown chicks were randomly assigned to five treatments groups (n = 150) and each treatment had five replicates of 30 birds each. The birds were reared for 48 weeks. The treatments were administered in the drinking water at doses of: 250 ml/l of LW (Lacto25), 500 ml/l of LW (Lacto50) or 1 ml/l of ACIDAL® ML (Aci). A positive control group (T+) was treated with 500 mg/l of Tetracolivit (an antibiotic). The negative control group (T-) did not receive any treatment in the drinking water. 4. Administration of LW or ACIDAL® ML in the drinking water reduced (P < 0.05) the pH in the crop, proventriculus, ileum and caeca, as well as total coliform bacteria and E. coli, but increased Lactobacillus spp. in the ileum and caecum, compared to the negative control. 5. Oviposition was earlier in the birds in both the Lacto50 and Aci groups. The weight of birds at first lay and point of lay in the four treated groups was higher than those in negative control group. Furthermore, egg production was increased by 10.44% in birds receiving Lacto25, but the weight and quality traits were unaffected, while the egg shell ratio was higher in the Aci group compared to the other treatments. 6. The data indicated that addition of LW or ACIDAL® ML improved hens' performance by modifying gut pH and microflora.

A Novel Phytase Derived from an Acidic Peat-Soil Microbiome Showing High Stability under Acidic Plus Pepsin Conditions

Four novel phytases of the histidine acid phosphatase family were identified in two publicly available metagenomic datasets of an acidic peat-soil microbiome in northeastern Bavaria, Germany. These enzymes have low similarity to all the reported phytases. They were overexpressed in <i>Escherichia coli</i> and purified. Catalytic efficacy in simulated gastric fluid was measured and compared among the four candidates. The phytase named rPhyPt4 was selected for its high activity. It is the first phytase identified from unculturable Acidobacteria. The phytase showed a longer half-life than all the gastric-stable phytases that have been reported to date, suggesting a strong resistance to low pH and pepsin. A wide pH profile was observed between pH 1.5 and 5.0. At the optimum pH (2.5) the activity was 2,790 μmol/min/mg at the physiological temperature of 37°C and 3,989 μmol/min/mg at the optimum temperature of 60°C. Due to the competent activity level as well as the high gastric stability, the phytase could be a potential candidate for practical use in livestock and poultry feeding

Identification and characterization of a mesophilic phytase highly resilient to high-temperatures from a fungus-garden associated metagenome

Phytases are enzymes degrading phytic acid and thereby releasing inorganic phosphate. While the phytases reported to date are majorly from culturable microorganisms, the fast-growing quantity of publicly available metagenomic data generated in the last decade has enabled bioinformatic mining of phytases in numerous data mines derived from a variety of ecosystems throughout the world. In this study, we are interested in the histidine acid phosphatase (HAP) family phytases present in insect-cultivated fungus gardens. Using bioinformatic approaches, 11 putative HAP phytase genes were initially screened from 18 publicly available metagenomes of fungus gardens and were further overexpressed in Escherichia coli. One phytase from a south pine beetle fungus garden showed the highest activity and was then chosen for further study. Biochemical characterization showed that the phytase is mesophilic but possesses strong ability to withstand high temperatures. To our knowledge, it has the longest half-life time at 100 °C (27 min) and at 80 °C (2.1 h) as compared to all the thermostable phytases publicly reported to date. After 100 °C incubation for 15 min, more than 93 % of the activity was retained. The activity was 3102 μmol P/min/mg at 37 °C and 4135 μmol P/min/mg at 52.5 °C, which is higher than all the known thermostable phytases. For the high activity level demonstrated at mesophilic temperatures as well as the high resilience to high temperatures, the phytase might be promising for potential application as an additive enzyme in animal feed.