Principle and development of single base editing technology and its application in livestock breeding / 生物工程学报

CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein) is widely used in the field of livestock breeding. However, its low efficiency, untargeted cutting and low safety have greatly hampered its use for introducing single base mutations in livestock breeding. Single base editing, as a new gene editing tool, can directly replace bases without introducing double strand breaks. Single base editing shows high efficiency and strong specificity, and provides a simpler and more effective method for precise gene modification in livestock breeding. This paper introduces the principle and development of single base editing technology and its application in livestock breeding.

Antibiotic resistance in environment of animal farms / 生物工程学报

World Health Organization has recognized antibiotic resistance is one of the serious threats to public health and food-safety in the 21st century. Recently, the antibiotic resistance gene (ARG) has been widely considered as a new pollutant. Now, many studies suggested that animal farm is one of the major reservoirs of ARGs. Antibiotic resistance bacteria and antibiotic resistance genes enter the environment along with animal excrement, accelerating the spread of ARGs in the environment. In the livestock and poultry breeding environment, ARGs and antibiotic resistant bacteria could be transmitted to humans through the food chain, water or air, posing a great threat to public health. This review highlights the prevalence of antibiotic resistant bacteria and antibiotic resistant genes in livestock-breeding environment, the retention and spread of ARGs and the method used to study the antibiotic resistance, which will provide certain support for risk assessment of antimicrobial resistance in food animal breeding environment.

Ceftiofur-loaded PHBV microparticles: a potential formulation for a long-acting antibiotic to treat animal infections

Background: The infectious diseases in the livestock breeding industry represent a significant drawback that generates substantial economic loss and have led to the indiscriminate use of antibiotics. The formulation of polymeric microparticles loaded with antibiotics for veterinary use can: reduce the number of required doses; protect the drug from inactivation; and maintain a sustained-release of the antibiotic drug at effective levels. Accomplishing all of these goals would have a significant economic and animal health impact on the livestock breeding industry. Results: In this work, we formulated ceftiofur-loaded PHBV microparticles (PHBV-CEF) with a spherical shape, a smooth surface and diameter sizes between 1.65 and 2.37 μm. The encapsulation efficiency was 39.5 +/- 1.1 percent w/w, and we obtained a sustained release of ceftiofur in PBS-buffer (pH 7.4) over 7 days. The antibacterial activity of ceftiofur was preserved after the encapsulation procedure, and toxicity of PHBV-CEF microparticles evaluated by MTS was represented by an IC50 > 10 mg/mL. Conclusions: Our results suggest that PHBV-CEF particles have a potential application for improving the treatment of infectious diseases in the livestock breeding industry.