Expression of the Extracellular Domain of SLA-1 Derived from Topigs Pig in Escheichia coli NH3 and N2O emission and nitrogen loss rate from biogas liquid produced by pig slurry after topdressing on vegetable fields Single nucleotide polymorphisms and genetic effects of CAST gene on meat quality traits in pigs The diversity of PLFAs biomarkers for the microbial community in the stroma cushion of non-pollution pigsty