Effects And Mechanism Of Rare Earth-Chitosan Chelate On Growth Performance Of Carassius Auratus L.

A feeding study was performed to investigate possible performance enhancing effects of the Rare Earth-Chitosan Chelate (RECC) on growth performance, digest enzyme activity, digest structure and quantity of IGF-â… mRNA expressed in hepatopancreas of Carassius auratus L. Three hundred and sixty individuals (about 5.0g) were allotted to four dietary treatments: a control group and three RECC-treated groups. RECC-treated groups were supplemented with 800mg, 1600mg and 2400mg of RECC per kg feed respectively. Each group had three duplicates. The whole feeding period lasted for sixty days. Results were shown as fellows:1. RECC added in the diet improved the growth of C. auratus L. significantly. When added 0.08% RECC in the diet, final average weight of fishes was significantly higher than that of the control group (P<0.01), and weight gain rate of this group was remarkably higher than the control group (P<0.05). Meanwhile, when added 0.08%, 0.16% and 0.24% RECC in the diet, special growth ratio of each group had raised 51.69%, 14.41% and 28.81% ( P>0.05 ) . Compared with the control group, protein efficiency ratio of 0.08%, 0.16% and 0.24% RECC group was 52.78%, 12.50% and 23.61% higher respectively ( P>0.05) ; feed coefficient had decreased 42.96%, 9.62% and 22.30% respectively( P>0.05) ; biology synthesis evaluation of each experimental group was 1.53, 1.11 and 1.22.2. RECC added in diet enhanced digest enzyme activity. It was found that in comparison with the control group, the 0.08% RECC group had a better intestinal amylase and lipase activity (P<0.01), as well as protease activity (P<0.05); the 0.16% RECC group also had a better intestinal amylase, protease and lipase activity (P<0.01); the intestinal lipase activity in the 0.24% group was significantly (P<0.01) higher than that in the control group, as well as amylase and protease activity (P<0.05). However, three RECC-treated groups all had no significantly influence on amylase, protease and lipase activity in hepatopancreas (P>0.05).3. RECC added in diet promoted the development of intestine. It was found that RECC-treated groups had higher numbers of plicamucosa than the control group, and plicamucosas became longer and narrower. Compared with the control group, the 0.08% RECC group had a better number of plicamucosa (P<0.05), a lower width of policamucosa(P<0.05), and a higher number of goblet cell (P<0.05); the 0.16%RECC group had a better number of goblet cell (P<0.01). Scanning electron microscope observation showed that microvilli in RECC-treated groups were more uniform and dense than the control group.4. RECC added in diet encouraged the expression of IGF-â… mRNA in hepatopancreas. Quantities of IGF-â… mRNA in 0.08%, 0.16% and 0.24% RECC groups were 47.44%, 32.54% and 29.70% higher than control group (P<0.01). No significant differences were found among the three RECC groups (P>0.05).