Effect of Extremely Thermophilic Bacteria on Amino Acid Degradation of High-temperature Treated Dead Pigs

Effect of addition of mixed extremely thermophilic bacteria on the degradation of amino acids in the high-temperature-treated pig carcass was studied.Samples applied in this study included materials of dead, diseased pigs prior to fermentation (Group Q) and after aseptic treatment (thermophile-free Group Wj that had been composted for 60 days) as controls, as well as those with additions of various ultra-thermophiles at 0.05%, 0.08%, 0.10% or 0.12%.Changes on the composition and content of amino acids of the samples after treatments were determined. The Illumina MiSeq method was used to analyze the microbial community on the samples. The 16S gene sequencing data obtained were compared to a reference genome database of known metabolic functions to predict those of the bacteria collected. The results showed that the addition of 0.08%-0.12% thermophiles significantly promoted the amino acid degradation that significantly reduced the total and individual amino acid contents. The reductions on total amino acid content were 7.04%-8.49% with an addition of the thermophiles more than 0.05% (P < 0.05)as the asparagine, threonine, glycine, alanine, leucine, phenylalanine, lysine contents decreased significantly. On the other hand, the degradations on glutamic acid, valine, isoleucine, tyrosine and arginine did not differ significantly in Group Wj. The amino acid metabolic functions of the dead pigs before and after treatment were significantly different. Those of Group Q and the treatment groups were significantly different indicating the addition of 0.08%-0.12% the extremely thermophilic bacteria enhanced the metabolism and amino acid degradation in the high-temperature-treated pig carcass, and that the effect was similar to a 60 day compost fermentation.