Effects Of The Cyclic Starvation-Refeeding On Growth Performance, Body Composition, Digestive Enzymes And Antioxidant Enzymes Of Megalobrama Amblycephala Yih And Cyprinus Carpio Var.Jian

The purpose of this study was to investigate the effects of the cyclic starvation-refeeding on growth performance, body composition, digestive enzymes and antioxidant enzymes of Megalobrama amblycephala Yih and Cyprinus carpio var. Jian to provide theoretical basis for compensatory growth and culturing skills of Megalobrama amblycephala Yih and Cyprinus carpio var. Jian. The study included two parts:Part I:A 48-day-multi-cycle experiment was carried out to determine the effects of cyclic starvation-refeeding on growth performance, body composition, digestive enzymes activities and antioxidant enzymes activities in juvenile Megalobrama amblycephala Yih with initial weight of(4.5±0.2)g. Fish were assigned one of five groups,namely the control group (daily feeding), S1F1 (feeding every other day), S2F2 (starvation 2d,feeding 2d), S4F4 (starvation 4d,feeding 4d) and S8F8 (starvation 8d,feeding 8d). By the end of the experiment, Weight Gain Ratio(WGR) of S1F1,S2F2 had no significant difference from that of the control group(P>0.05). Weight Gain Ratio(WGR) of S4F4, S8F8 were significantly lower than that of the control group(P<0.05).However, Specific Growth Rate(SGR) and Feeding Rate(FR) of all four test groups were significantly higher than that of the control group(P<0.05). Feed Conversion Ratio(FCR) of all four test groups had no significant difference from that of the control group(P>0.05). No significant difference was observed in Moisture, protein content, ash content of whole body of all groups(P> 0.05); Lipid content of whole body of S2F2, S4F4, S8F8 were significantly lower than that of the control group(P< 0.05).Lipid content of whole body of S1F1 had no significant difference from that of the control group(P>0.05). Hepatosomatic Index(HSI) of S4F4, S8F8 were significantly higher than that of the control group(P<0.05). Hepatosomatic Index(HSI) of S1F1, S2F2 had no significant difference from that of the control group(P> 0.05). Carcass Ratio(CR) of S2F2, S4F4, S8F8 were significantly lower than that of the control group(P<0.05). Carcass Ratio(CR) of S1F1 had no significant difference from that of the control group(P>0.05). No significant difference was observed in Condition Factor(CF) between all groups(P>0.05).Intestinal digestive enzymes activities of all four test groups were higher than those of the control group, besides Lipase and Amylase were significantly higher than those of the control group(P<0.05). Activities of SOD in liver of four test group deceased with inceasing length of starvation in single cycle. Activities of SOD of S2F2, S4F4, S8F8 were significantly lower than that of the control group(P<0.05). Activities of SOD of S1F1 were significantly higher than that of the control group(P< 0.05).In all, S1F1 (feeding every other day)had the similar and even better performance compared with the control group (feeding every other day) in aspects of growth performance, body compositon, digestive enzymes and antioxidant enzymes, which could be tried in practice production.Part II:This experiment was conducted to investigate the effects of cyclic starvation-refeeding on growth performance, body composition, digestive enzymes activities and antioxidant enzymes activities in Cyprinus carpio var. Jian with initial weight of (1.5±0.2) g. The control group was fed continuously for 60 d, while the test groups were subjected to 9 different repetitive cycles of starvation-refeeding (S1F2, S1F3, S1F4, S2F4, S2F6, S2F8, S4F8, S4F12, S4F16) respectively. The results showed that Weight Gain Ratio (WGR)increased with increasing length of refeedng in single cycle within a certain starvation day, having the trend of S1F2<S1F3<S1F4; S2F4<S2F6<S2F8; S4F8< S4F12<S4F16.No significant difference was observed in WGR between S1F4, S2F8, S4F16 and control group(P>0.05).The WGR of other test groups were significantly lower than that of the control group (P<0.05). Specific Growth Rate (SGR)and Feeding Rate (FR)of all test groups were significantly higher than control group (P<0.05),No significant difference was observed in the Feed Conversion Ratio(FCR) of all groups(P>0.05). No significant difference was observed in moisture, protein content, ash content of whole fish composition, nor in moisture, protein content, lipid content of carcass compositon and nor in moisture, protein content of liver compositon in all groups(P>0.05).However lipid content of whole fish of all test groups were lower than that of control group,with the trend of S1F2<S1F3<S1F4; S2F4<S2F6<S2F8; S4F8<S4F12<S4F16,indicating that lipid was inceasingly consumed with increasing frenquency of starvation. Lipid content in liver of all test groups were significantly higher than control group (P<0.05), with the trend of S1F2<S1F3<S1F4; S2F4< S2F6< S2F8; S4F8<S4F12<S4F16. No significant difference was observed in Condition Factor(CF), Viscerasomatic Index(VSI) and Hepatosomatic Index(HSI) between all groups.The same trend that(S1F2<S1F3<S1F4 S2F4<S2F6<S2F8; S4F8< S4F12< S4F16) was observed in both CF and HSI. Activities of Protease and Lipase in intestine of all test groups were signicantly higher than that of the control group (P<0.05), and the same trend that S1F2<S1F3<S1F4; S2F4< S2F6<S2F8; S4F8<S4F12<S4F16 was observed in both. Activities of Amylase in intestine of all test groups were higher than that of the control group, having no clear regularity.Activities of SOD in liver of all test groups were higher than that of control group. No significant difference was observed in activities of GOT and GPT in liver of all groups(P>0.05). In all, S1F4(starvation 1d,feeding 4d), S2F8(starvation 2d, feeding 8d),S4F16(starvation 4d, feeding 16d) had similar growth performance, body compositon compared with the control group (feeding everyday), had a higher activities of digestive enzymes and antioxidant enzymes and tent to be a labor-saving feeding mode,which could be tried in practice production.