title: Growth enhancement of fowls by dietary administration of recombinant yeast cultures containing enriched growth hormone.
abstract: In present study the methylotrophic yeast, Pichia pastoris, was used to express a recombinant growth hormone (rGH) gene of swine. A synthetic secretion cassette was constructed using the promoter of the alcohol oxidase1 gene (AOX1), and a alpha-factor signal peptide. After electroporatic transformation and zeocin selection, several clones exhibited high levels of rGH protein expression constituting more than 20% of total yeast protein. Over 95% of rGH was shown to be export into the culture supernatant. Yeast transformant containing the highest recombinant growth hormone level (rGH yeast) and native GS115 Pichia pastoris (non-rGH yeast, as a control) were separately cultured, harvested and adsorbed by wheat bran. Yeast cultures of four dosages (0.05, 0.1, 0.2, and 0.4%) were mixed respectively with chick basal diet and fed to simulated country chickens for 9 weeks. The results showed that, when compared to control chicks, the percentage of body weight gain was improved significantly (P<0.05) in chicks fed with diets containing 0.1 or 0.2% rGH-rich yeast culture at brooding stage, and in chicks fed with 0.4% rGH-rich yeast culture at growing stage. The average weight gain in rGH yeast treated groups for the full-term (0 to 63d) and short term (43 to 63d) of growth were 10.6 and 9.4%, respectively, better than the non-rGH yeast control group. These experimental data suggest that the use of rGH-containing yeast as a supplement in fed provided an alternative approach for growth improvement in simulated country chickens.
authors.affiliation: Department of Zoology, College of Life Science, National Chung Hsing University, Taichung, Taiwan. chchen1@gragon.nchu.edu.tw
authors.forename: C M
authors.initials: CM
authors.lastname: Chen
authors.forename: W T
authors.initials: WT
authors.lastname: Cheng
authors.forename: Y C
authors.initials: YC
authors.lastname: Chang
authors.forename: T J
authors.initials: TJ
authors.lastname: Chang
authors.forename: H L
authors.initials: HL
authors.lastname: Chen
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics; D000595:Amino Acid Sequence; D000821:Animal Feed; D000818:Animals; D001483:Base Sequence; D002645:Chickens / Q000254:growth & development*; D003001:Cloning, Molecular; D019587:Dietary Supplements; D013006:Growth Hormone / Q000008:administration & dosage / Q000235:genetics*; D000072235:Mating Factor; D010455:Peptides / Q000235:genetics; D010843:Pichia / Q000235:genetics; D011401:Promoter Regions, Genetic; D021382:Protein Sorting Signals / Q000235:genetics; D011994:Recombinant Proteins / Q000008:administration & dosage; D013552:Swine; D015430:Weight Gain
chemical_list: D010455:Peptides; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D000072235:Mating Factor; D013006:Growth Hormone; D000429:Alcohol Oxidoreductases; C019643:alcohol oxidase