Application of porcine lipase secreted by pichia pastoris to improve fat digestion and growth performance of postweaning piglets.

The aim of the study was to use Pichia pastoris to express a recombinant porcine lipase gene (pLip). The expression-secretion cassette was constructed using the P. pastoris GAPDH (glyceraldehyde-3-phosphate-dehydrogenase) promoter and an 89-residue prepro-alpha-factor secretion signal fused to the AOX1 terminator (the pGAPZalphaA vector). A total of 1,408 bp of pancreatic lipase cDNA was produced, which was located from the position of 4-nt upstream of ATG to 1408-nt inside the intact coding region of the pLip sequence. In an animal trial, three concentrations of recombinant lipase activity (0, 5,000 and 10,000 U/kg) were blended with the basal diet and fed to weaned piglets for six weeks. During the experimental period, the growth performance (bodyweight, feed intake, and feed efficiency) of the test groups was superior to that of the control group (p < 0.05). Furthermore, the group fed the diet blended with 10,000 U/kg of recombinant lipase showed significant (p < 0.05) increases in blood triglyceride (TG) concentration on the seventh day postweaning. These results suggested that the porcine lipase protein yielded by transformed yeast cells may improve fat digestibility and enhance the growth performance in postweaning piglets.

Production of recombinant porcine colipase secreted by Pichia pastoris and its application to improve dietary fat digestion and growth of postweaning piglets.

Recombinant porcine pancreatic colipase (pCoL) was produced in the methylotrophic yeast Pichia pastoris. A synthetic yeast secretion cassette was constructed with the constitutive promoter of the glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) gene and the yeast alpha-mating factor signal peptide. The pCoL cDNA corresponding in the coding sequence, excluding a 16-amino acid segment of the native signal sequence, was cloned into the pGAPZalphaB vector and integrated into the genome of P. pastoris. Yeast transformants were cultured and bioactive pCoL protein was detected in the supernatant at a high-level of 126.8 mg/L after 3 days of culture. The transformed yeast containing the highest recombinant colipase level (pCoL yeast) and native yeast GS 115 not containing pCoL (non-pCoL yeast, as a control group) were separately cultured and the supernatants were adsorbed by dried skim milk. In an animal trial, two concentrations of colipase activity (0 vs. 5,000 U/kg in the diet) were blended with the pig corn-soybean basal diet and fed to weaned piglets for 4 weeks. The pCoL-administrated test group gained significantly more weight than piglets in the control group when measured at Day 15 (11.84 +/- 0.70 vs. 10.59 +/- 0.39 kg, P < 0.05), Day 22 (15.84 +/- 0.95 vs. 14.32 +/- 0.59 kg, P < 0.01), and Day 28 (20.19 +/- 1.47 vs. 18.54 +/- 0.92 kg, P < 0.01) after weaning. The blood triglyceride (TG) concentrations were significantly increased in the experimental test group that received recombinant colipase on the 28th day of postweaning when compared with that of the control group (32.50 vs. 16.37 mg/dL; P < 0.0001). These experimental data suggest that the use of recombinant porcine colipase as a dietary supplement provides an alternative approach for improving fat digestion and enhancing growth in postweaning piglets.