title: Nutrient assessment of olive leaf residues processed by solid-state fermentation as an innovative feedstuff additive.
abstract: OBJECTIVE
  Olive leaf residue feedstuff additives were prepared by solid-state fermentation (SSF), and its feeding effects on broiler chickens were examined.
  
  
  RESULTS
  The fermentation's nutrient value, that is, protein enrichment, cellulase activity, tannic acid degradation and amino acid enhancement, was determined. The effect of different strains, including molds (Aspergillus niger, Aspergillus oryzae and Trichoderma viride) and yeasts (Candida utilis, Candida tropicalis and Geotrichum candidum), and the fermentation time on the nutrient values of the feedstuff additives was investigated. The experimental results showed that the optimal parameters for best performance were A. niger and C. utilis in a 1 : 1 ratio (v/v) in co-culture fermentation for 5 days. Under these conditions, the total content of amino acids in the fermented olive leaf residues increased by 22·0% in comparison with that in the raw leaf residues. Both Glutamic acid and Aspartic acid contents were increased by more than 25·4%. Broiler chickens fed with different amounts of feedstuff additives were assessed. The results demonstrated that the chicken weight gains increased by 120%, and normal serum biochemical parameters were improved significantly after 10% of the feedstuff additives were supplemented to the daily chicken feed for 28 days.
  
  
  CONCLUSIONS
  The co-culture combination of A. niger and C. utilis with SSF for olive leaf residue had the best nutrient values. The addition of 10% fermented olive leaf residue facilitated the chicken growth and development.
  
  
  CONCLUSIONS
  This study reveals that olive leaf residues fermented by SSF exhibited considerable potential as feed additives for feeding poultry.
authors.affiliation: National Engineering Lab. for Biomass Chemical Utilization, Key and Open lab. on Forest Chemical Engineering, SFA, Key Lab. of Biomass Energy and Material, Institute of Chemical Industry of Forest Products, CAF, Nanjing, Jiangsu, China.|Institute of New Technology of Forestry, CAF, Beijing, China.
authors.forename: P-J
authors.initials: PJ
authors.lastname: Xie
authors.affiliation: National Engineering Lab. for Biomass Chemical Utilization, Key and Open lab. on Forest Chemical Engineering, SFA, Key Lab. of Biomass Energy and Material, Institute of Chemical Industry of Forest Products, CAF, Nanjing, Jiangsu, China.|Institute of New Technology of Forestry, CAF, Beijing, China.
authors.forename: L-X
authors.initials: LX
authors.lastname: Huang
authors.affiliation: National Engineering Lab. for Biomass Chemical Utilization, Key and Open lab. on Forest Chemical Engineering, SFA, Key Lab. of Biomass Energy and Material, Institute of Chemical Industry of Forest Products, CAF, Nanjing, Jiangsu, China.|Institute of New Technology of Forestry, CAF, Beijing, China.
authors.forename: C-H
authors.initials: CH
authors.lastname: Zhang
authors.affiliation: National Engineering Lab. for Biomass Chemical Utilization, Key and Open lab. on Forest Chemical Engineering, SFA, Key Lab. of Biomass Energy and Material, Institute of Chemical Industry of Forest Products, CAF, Nanjing, Jiangsu, China.
authors.forename: Y-L
authors.initials: YL
authors.lastname: Zhang
mesh_terms: D000821:Animal Feed; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001234:Aspergillus niger / Q000378:metabolism; D001236:Aspergillus oryzae / Q000378:metabolism; D002645:Chickens / Q000254:growth & development*; D019587:Dietary Supplements / Q000032:analysis; D005285:Fermentation; D018698:Glutamic Acid / Q000378:metabolism; D031658:Olea / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D014242:Trichoderma / Q000378:metabolism
chemical_list: D001224:Aspartic Acid; D018698:Glutamic Acid
keywords: amino acid; broiler chicken feeding test; cellulase activity; olive leaf residues; protein enrichment; solid-state fermentation