Effects of feed palygorskite inclusion on pelleting technological characteristics, growth performance and tissue trace elements content of blunt snout bream (Megalobrama amblycephala)

The study aimed to investigate the effect of feed palygorskite inclusion on pelleting technological characteristics, growth performance and tissue trace elements content of blunt snout bream, Megalobrama amblycephala. Diets without (control group) or with 2% palygorskite were pelleted and were measured for pelleting technological characteristics. Then the diets were fed to two groups of fish in four replicates (30 fish per replicate) for six weeks. Compared with the control group, dietary 2% palygorskite inclusion enhanced pellet production rate, pellet durability and the degree of starch gelatinization of pellet, and reduced percentage of fines. There was no difference in the weight gain, feed conversion rate, condition factor, hepatosomatic index and viscera/body ratio of fish between groups. Palygorskite supplementation significantly enhanced the Fe content in the blood and muscle and Zn content in the muscle, but reduced muscular Cd concentration. However, the accumulations of Cu and Pb in the body were not affected by palygorskite. The results indicated that dietary palygorskite supplementation could enhance pellet production efficiency, pellet quality, and alter trace elements accumulation in the tissues without impairing growth performance of blunt snout bream. (C) 2015 Elsevier B.V. All rights reserved.