Nutritional evaluation of fermented palm kernel cake using red tilapia

The use of palm kernel cake (PKC) and other plant residues in fish feeding especially under extensive aquaculture have been in practice for a long time. On the other hand, the use of microbial-based feedstuff is increasing. In this study, the performance of red tilapia raised on Trichoderma longibrachiatum fermented PKC (TL-PKC) was evaluated. Seven isonitrogenous and isocaloric diets were formulated. Reference diet, D1 had no PKC, while the other diets, D2 to D5 contained 10, 20, 30and 40% fermented PKC (TL-PKC), respectively. All diets contained 1% chromic oxide as an inert marker. Red tilapias of average weight of 2.5 g were fed on these six diets for a period of 8 weeks. The fish were fed at 4% of their body weight, twice a day. There was no difference in mortality rate of fish on the various diets used. However, weight gain decreased with an increase of TL-PKC in diets. There were significant (P £ 0.05) differences in the apparent digestibility coefficient (ADC) of protein and drymatter between the reference diet and diet containing TL-PKC. The ADC of both protein and dry matter generally decrease when the percentage TL-PKC was increased in the test diets. There was also no significant difference in carcass protein content among fish on the various diets. However, there was a significant (P £ 0.05) increase in the levels of phosphorus, calcium and copper in the carcass of fish raised on TL-PKC, but the level of lipids was significantly reduced. Decreasing dry matter and protein digestibility with corresponding weight reduction may have resulted from increased crude fibre content of diets with TL-PKC

Mycelial growth interactions and mannan-degrading enzyme activities from fungal mixed cultures grown on palm kernel cake

Palm kernel cake (PKC), a by-product of the palm kernel oil extraction process contains mannan as its main polysaccharide. Mixed culture microbial degradation may enhance mannan-degrading enzymesproduction. Therefore, the objective of the study was to examine the nature of mycelial interactions and corresponding production of mannan-degrading enzymes of PKC. Fungal interactions was carried outusing Sclerotium rolfsii and Aspergillus niger co-cultured with three Trichoderma strains (Trichoderma harzianum, Trichoderma longiobrachiatum and Trichoderma koningii) on potato dextrose agar (PDA) in disposable petri-dishes. Measurements of growth diameters were taken on days 2 and 13. For mannandegrading enzyme production, single and co-cultures of these fungi were carried out under submergedcultivation for 13 days with PKC as the carbon source. About 57% of observed interactions on PDA were deadlock, 29% replacement and 14% intermingling. In Trichoderma sp./A. niger mixed cultures,there was an overall significant enhancement of enzyme: 2 to 200 fold (b-D-mannanase), 8 to 25 fold (bmannosidase) and from no change to 15 fold increase (a-galactosidase). There was no obviousrelationship between enzyme production and protein yield. However, co-culturing of A. niger with the Trichoderma strains showed an enhancement of mannan-degrading enzyme activities without reducingbiomass yield

Valorization of a biomass: phytochemicals in oilseed by-products

A huge amount of residue is released every year in agricultural and food industries. If this waste is valorised properly, it would be very beneficial from both economic and environmental aspects. Recently, seeds of oil crops have been getting great interest due to their waste rich in a great variety of lipophilic and hydrophilic phytochemicals. On the other hand, oilseed processing by-products comprise approximately 35 millions of tons seed for oil in European Union. Therefore, this remarkable amount of residue should be considered as a resource from waste to health. The purpose of the present research is to introduce the types of oilseed by-product and their high added value phytochemicals by summarizing the recent studies on the valorization of different wastes of several oilseed crops. This research also supplies an overview of the oilseed sources with their botanical names, production regions and target phytochemical ingredients. Moreover, further remarks with some certain concerns are discussed