COMPENSATORY GROWTH AFTER EXPERIENCING CYCLES OF FEED DEPRIVATION AND RE2FEEDING IN PACIFIC SALMON, ONCORHYNCHUS SPP

A 64-days compensatory growth experiment in Pacific Salmon, Oncorhynchus spp. was conducted to determine the ef-fects of growth following starvation infreshwater. 108 Pacific salmon (initial weight ca.240g) were divided into 6 treatments with triplicate groups in a recirculated system at 15.5 ± 3.7 ℃. The control fishes were fed continuously and the test fishes were expe-riencing 1day deprivation and 1 day re2feeding,2 days deprivation and 2 days re-feeding, or 4,8,16 days deprivation and 4,8, 16 days re-feeding. The results indicated that the survival rate (SR) of fish in all groups is 100 % and the weight-gain in fish of test group 1,2,3 is close to fish at the control group, but fish in test group 4, 5 are significantly lower than those of the control group. The specific growth rate (SGR),feeding rate (FR),feed efficiency (FE) of fish in test group 1,2,3 were significantly higher than those of the control group (P < 0.05 or 0.01),but fish in test group 4,5 were significantly lower than those in the control group (P < 0.01). The condition factor (CF) and the rate of liver/ body,content of lipid and glycogen in liver, content of lipid in muscle of fish in all test groups were in different degree lower thanfish in the control group. The ratio of total saturated fatty acids(ΣSFA)in lipidof liver withfish in test groups was higher and total polyunsaturatedfatty acid (ΣPUFA) was lower than fish in the control group. The indexes of triglyceride(TG), cholesterol (CHOL),low density lipoprotein (LDL2C) in plasma of fish in test group 1,2,3 were significantly lower than those in the control group, but glucose in plasma and thyroxine T4in serum were significantly higher than those in the control group (P < 0.05). These results suggested that Pacific salmon with initial weight ca. 240g, which were deprivedfeedfor 1,2,4 days and then were re-fed for same days subsequently during 64 days peri-od, showed a positive compensatory growth through raising the feeding rate (FR) and feed efficiency (FE),but the fish which were deprived feed for 8-16 days and then were re2fed same days during the same period, showed a negative compensatory growth due to decrease of feeding rate (FR) and feed efficiency(FE).