Aqueous fractionation improves the nutritional value of wheat distillers grains for rainbow trout (Oncorhynchus mykiss)

Fractionation of wheat wet distillers grains (WWDG) was performed to reduce non‐starch polysaccharides (NSP) and increase protein content. WWDG was collected from two ethanol plants, and protein was extracted by the addition of water, autoclaving to precipitate protein and drying in a forced air oven at 55 °C to create WWDG–protein concentrate (WWDG–PC). This process increased crude protein (CP) and decreased NSP in the WWDG–PC (P < 0.05). Dry matter and energy digestibility of WWDG–PC in rainbow trout were increased by fractionation (P < 0.05). A 56‐day growth trial was performed to determine the effect of feeding WWDG–PC on growth performance of rainbow trout. Rainbow trout (n = 18/tank; body weight = 231 g; 3 tanks/treatment) were fed diets containing 0, 75, 150, 225 or 300 g kg^?1 WWDG–PC. All diets were formulated to contain 386 g kg^?1 digestible CP and 17.6 MJ kg^?1 digestible energy. There was no significant linear or quadratic relationship between inclusion rate and growth, feed intake or feed conversion, indicating that at inclusion levels of up to 300 g kg^?1 of WDDG–PC does not reduce the growth performance of rainbow trout.     

Studies on the artificial propagation of Monopterus albus (Zuiew)

Artificial propagation of Monopterus albus (Zuiew) was conducted during their spawning season in the present study. Different doses of luteinizing-hormone-releasing-hormone analogue (LHRH-A) were tested for inducing the ovulation of brood females. No significant difference was found in the degree-hours and fertilization rates between three different doses (0.1, 0.2 and 0.3 μg LHRH-A g^-1 fish). A fertilization solution of 0.3% NaCl produced significantly higher fertilization rates than the other three solutions (0.5% NaCl, 0.65% NaCl and water). Fertilization times ranging from 5 to 2 0 min gave no significant difference in the fertilization rates. The embryonic and larval development of M. albus was observed and illustrated. The hatching time of eggs of M. albus was about 140 h in the 28-3 0^oC water temperature range. Using Tubifex spp. for the first food for the larval nursery gave higher growth rate than two other foods, zooplankton and artificial food.