A method for extracting coenzyme Q10 (CoQ10) from Artemia was developed. 1 g of fresh Artemia was incubated with 75 % acetic acid at (30 ± 2)°C for 24 h, followed by three consecutive extractions with a mixture of 5 mL of hexane and 5 mL of ethanol, then analysis by a validated high-performance liquid chromatography with a diode-array detector. The calibration curve for CoQ10 was linear in a range of 1–50 μg mL−1. The limits of detection and quantification were 0.3 μg mL−1 and 1.1 μg mL−1, respectively. Mean recoveries were 94–100 % with a high precision of below 10 %. The method developed was found to be simple, efficient and the time required for releasing CoQ10 from Artemia was short. The method provides not only low energy consumption but is also practical for industrial applications.

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The effect of feeding time was studied in rainbow trout fed different dietary levels of fat. Fish were fed either 1 h after light on in the morning or 1 h after light off in the evening with a low energy diet (LE, 6 % lipid) or a high energy diet (HE, 23 % lipid). Regardless of the diet, apparent digestibility and post-prandial protein synthesis were higher in fish fed in the morning than in those fed at the beginning of the night. In fish fed the LE diet in the morning, growth performance and nutrient retention efficiency tended to be higher than in those fed at the beginning of the night. In contrast, fish fed the HE diet in the morning had lower protein growth rate, protein content and protein retention efficiency than those fed in the evening. These results suggest that protein metabolism might be involved in the effect of feeding time on growth and that there is an interaction between the time of feeding and dietary level of fat on growth.

Biogas production is proposed as an alternative approach to using natural rubber Hevea brasiliensis latex serum, a major waste product from the production of concentrated latex. To make the most efficient use of the reactor size, the addition of macroalgal biomass as a co-substrate to the fermentation system was investigated. The biogas yield of latex serum as a single substrate was (398 ± 14) L per kg of volatile solids added (VSA). For the co-digestion system, algae mixed with serum were investigated at wet mass ratios of Chaetomorpha sp. to Ulva intestinalis to serum at 3 : 0 : 1, 2 : 0 : 2, 1 : 0 : 3, 0 : 1 : 3, 0 : 2 : 2 and 0 : 3 : 1. The co-digestion system with latex serum at 2 to 3 out of 4 parts produced the highest biogas yields within the range of 422-460 L kg