WANG Yu-heng1，2, LIU Wen-bin2, WANG Hui-chong1,CHEN Jun1, LUO Gui-lan1,XING Jun1
1.Department of Animal Husbandry & Veterinary Medicine，Jiangsu Polytechnic College of Agriculture and Forestry, Zhenjiang 212400,China;2.Key Laboratory of Aquaculture Nutrition of Jiangsu Province,College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
Abstract: Juvenile blunt snout breamMegalobramaamblycephalawith initial body weight of (0.80±0.02) g were randomly allotted into 36 tanks at a rate of 20 fish per tank and fed nine purified diets containing three linoleic acid(LA) levels (0.5%, 1.0% and 1.5%) and three α-linolenic acid(ALA) levels (0.5%, 0.9% and 1.3%)with tetraplication at water temperature of (27±3)℃ for 8 weeks. Weight gain, specific growth rate and protein efficiency ratio were shown to be increased first and then decreased significantly with increase in dietary LA and ALA levels(P<0.05),the maximum in the fish fed the diets containing 1.0% LA and 0.9% ALA. There was significantly higher food conversion ratio in the fish fed the diet containing 1.3% ALA than that in the fish in other groups(P<0.05) without significant difference in the fish fed the diets containing LA(P>0.05). The fish fed the diet containing 1.3% ALA had significantly higher condition factor (CF) than the other fish fed the diets containing ALA(P<0.05), and no significant differences in CF were found in the fish fed the diets containing LA. The fat content in whole body was found to be significantly increased with increase in dietary LA levels(P<0.05) while moisture and hepatopancreatic fat content was decreased with increase in dietary LA levels. No significant difference in condition factor, and moisture and fat in whold fish body was observed in the fish fed the diet containing ALA(P<0.05), though the minimal lipid content in the fish fed the diet containing 1.3% ALA. Also, there was significantly higher lipid content in hepatopancreas of the fish fed the diet containing 0.5% LA than that in the other groups(P<0.05). The fish fed the diet containing 0.5% LA had significantly lower activities of intestine lipase and protease than that the fish in the other groups(P<0.05), the minimum in the fish fed the diet containing the maximal ALA. It is concluded that 1.09% LA and 0.84% ALA are of the optimal for growth and best carcass quality in juvenile blunt snout bream.
2014, Vol. 29 
