Utilization of Waste Porphyra Products as Eco-friendly Feed Ingredients

摘要

We investigated the growth and hepatopancreatic enzyme activities in red sea bream, Pagrus major, fed diets containing waste nori, Porphyra spp. (red algae, purple laver) with different protein to fat ratios. Fingerlings of 10.1 g average body weight were fed for 10 weeks on the optimum fat and protein (11 and 55 96) control diet (CTD) and two higher fat and lower protein (19 and 42 % and 25 and 36 %, respectively) experimental diets (MFD and HFD). All diets were supplemented with 5 % waste nori. Weight gain, specific growth rate and feed efficiency in fish fed the CTD and MFD were higher than those in fish fed the HFD. Plasma total cholesterol, phospholipid, and free fatty acid concentrations and whole body crude fat content were increased as dietary fat level increased, whereas hepatopancreatic lipogenic enzyme activities (glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, NADP-isocitrate dehydrogenase and NADP-malate dehydrogense) were decreased as the dietary fat level increased. Aspartate aminotransferase activity of the MFD group was significantly lower than the activity of the CTD group. These findings suggest that dietary fat content can be increased from 11% to 19% by supplementing 5% waste nori in fingerling red sea bream diets.