Effects Of Fermentation, Exogenous Enzyme And Feeding Stimulants On Utilization Of Soybean Meal Protein By Japanese Flounder (Paralichthys Olivaceus)

Feeding trials were conducted in indoor culture system to investigate the effects of partially replacing fish meal (FM) in diets with fermented soybean meal (SBM) and unfermented SBM, supplemental exogenous enzyme and feeding stimulants on feed intake, growth and feed utilization of Japanese flounder (Paralichthys olivaceus). Results of the study are presented as follows:I. Effects of partially replacing fish meal with fermented soybean meal (FSBM) and unfermented soybean meal (USBM) in diets on feed intake, growth and feed utilization of Japanese flounder I: Effects of Candida utilis, Rhizopus oligosporus and Bacillus subtilis FSBM. The SBM were inoculated with a single Candida, Rhizopus or Bacillus strain and fermented to obtain 3 FSBM (CSBM, RSBM and BSBM). Fermentation decreased the amounts of phytate, trypsin inhibitor and soyasaponins and increased the amount of free amino acid in SBM (P<0.01). Ten isonitrogenous (50.5% crude protein) and isocaloric diets (20.5 kJ g-1) were formulated in which USBM protein replaced 0%, 30%, 45% and 60% FM protein (diet 1 - 4); CSBM, RSBM and BSBM protein respectively replaced 45% and 60% FM protein (diet 5 -10). Diet 1 was the control diet. At the end of the feeding trial, there was no significant difference in survival of the fish fed different diets (P>0.05). The fish fed the control diet had significantly higher weight gain rate (WGR) than the fish fed the diets containing 45% and 60% USBM, RSBM and BSBM protein (P<0.01) except for the fish fed the diets contained 45% CSBM and 30% USBM protein. The fish fed 45% CSBM protein diet had significantly higher feed intake (FI) and WGR than the fish fed 45% USBM protein diet (P<0.01). Partial replacement of FM by USBM significantly decreased the activities of digestive enzymes and apparent digestibility coefficients (ADC) of dry matter, crude protein and lipid (P<0.01). But the CSBM and RSBM significantly elevated the activities of digestive enzymes and the ADC when compared with USBM (P<0.01). The results of the present study indicated that CSBM protein can replace 45% FM protein in diet for Japanese flounder with good FI, growth and feed utilization, but the replacement of...