Determination of True Amino Acid Digestibility and Metabolizable Energy in Fermented Palm Kernel Meal with Aspergillus wentii TISTR 3075 for Chickens

The determination of energy and digestibility values of new added-value products is important for feed formulation. True amino acid digestibility and metabolizable energy of feedstuffs were evaluated in adult meat type crossbred chickens. Sulfur amino acids (cysteine and methionine) and lysine were limiting amino acids in palm kernel meal (solvent extract; PKM) and fermented palm kernel meal (FPKM) with Aspergillus wentii TISTR 3075. The FPKM with Aspergillus wentii TISTR 3075 lead to an increase in true amino acids digestibility except for arginine. The apparent metabolizable energy (AME; DM basis) of corn, PKM and FPKM were 3,628.88, 2,201.83 and 2,080.26 kcal/kg, respectively. The true metabolizable energy (TME) of PKM (DM basis: 2,958.21 kcal/kg) was slightly higher than FPKM (DM basis: 2,843.01 kcal/kg) while the nitrogen-corrected apparent metabolizable energy (AMEn), nitrogen-corrected true metabolizable energy (TMEn) of PKM (DM basis: 2,411.84 and 2,603.33 kcal/kg, respectively) were significantly higher than FPKM (DM basis: 2,153.11 and 2,333.07 kcal/kg, P = 0.03 and P = 0.02 respectively). Aspergillus wentii may use up nitrogen-free extract (NFE) in PKM as an energy source during the fermenting process, resulting in a lower metabolizable energy of FPKM when compared to PKM (without fermentation)

Effects of feeding rates on the growth, water quality and nutrient budget of western king prawn (Penaeus latisulcatus Kishinouye) reared in recirculating aquaculture systems

Feed rate is one of the important variables considered for the improvement in production of prawns. The effects of four feeding rates on growth, water quality and the nutrient budget of Penaeus latisulcatus were investigated for 98 days. The specific growth rate (SGR) at 3.0% feed rate was significantly higher than at all higher feed rates, and there was no significant difference in SGR between 4.5%, 6% and 7.5%. Total ammonia nitrogen concentrations in all treatments remained low in the safe range for prawn culture. Dissolved inorganic nitrogen and nitrate nitrogen were significantly higher (P < 0.05) in prawn tanks received feed rates of 6.0% and 7.5%. Total phosphorus and the soluble reactive phosphorus linearly increased with the progression of the trial and feeding rates. Nutrient conversion rates were significantly higher (P < 0.05) in prawns receiving the feeding rate of 3.0% than feeding rates of 6.0% and 7.5%. The lowest food conversion ratio was recorded at feeding rates of 3% and 4.5%. Nutrient budget showed that 6.01–15.99% nitrogen and 4.53–9.29% phosphorus of the nutrient inputs were retained in the prawn biomass. The results indicated that the growth and nutrient conversion rate may not increase with the increase above 3.0% of biomass per day