Effect Of Dietary Lipid Level On Growth Performance, Body Composition And Digestive Enzyme Activities Of Ancherythroculter Nigrocauda

The trial was conducted to evaluate the effects of dietary lipid levels ongrowth performance and body composition of Ancherythroculter nigrocauda. Fivehundred and fourty fish with average initial body weight of5.74±0.07g wererandomly divided into6groups (named L0to L5) with3replicates of30fish ineach replicate. Fish oil and soybean oil, mixing them1to1, were used as lipidsources. Six groups were fed diets with0(group L0, control group),4%(group L1),8%(group L2),12%(group L3),16%(group L4) and20%(group L5)lipid,respectively (measured lipid levels of6diets were0.52%,4.49%,8.98%,12.46%,14.58%and16.49%, respectively). The experiment lasted for60days.1. In the range of0to20%, with the increasing dietary lipid levels, the weightgain ratio, protein efficiency and specific growth ratio were originally increasedand then decreased; and the feed coefficient originally decreased and then increased.The regression model analysis showed the best dietary lipid level which couldacquire the best weight gain, protein efficiency, specific growth ratio and feedcoefficient was7.61%,8.49%,7.57%and8.45%, respectively.2. Whole body lipid level increased with the increase in dietary lipid levels;and when the dietary lipid level was8.98%, the body lipid level was significantlyhigher than that in control group (P<0.05), but there was a downward trend inprotein content, and the control group was significantly higher than the othergroups (P<0.05). No significant differences were found in whole body dry matter orash contents of fish fed the different lipid levels (P>0.05).3. No significant differences were found in condition factor of different dietarylipid levels (P>0.05). Different dietary lipid levels could influence onhepato-somatic index of A. nigrocauda significantly (P<0.05), and thehepato-somatic index increased with the increase in dietary lipid levels. The controlgroup was significantly lower than the groups L3, L4and L5(P<0.05), but therewas no significant differences with the groups L3, L4and L5(P>0.05). 4. Different dietary lipid levels had a significantly effect on activities ofprotease, amylase and lipase of A. nigrocauda. When the dietary lipid level was12.46%, the activities of protease, amylase and lipase reached the maximum value,484.03μg·Tyr/min·g,0.75mg·maltose/min·g and193.53U/mL respectively.5. Different dietary lipid levels had a significantly effect on activities oflipoprotein lipase, hepatic lipase and tolal lipase of A. nigrocauda, and the controlgroup was significantly lower than the other groups (P<0.05). With the increasingdietary lipid levels, the activities of lipoprotein lipase, hepatic lipase and tolallipase of A. nigrocauda were originally increased and then decreased, and when thedietary lipid level was12.46%, the activities of lipoprotein lipase, hepatic lipaseand tolal lipase reached the maximum value, and was significantly higher than theother groups (P<0.05).The results suggested that, different dietary lipid levels had a significantlyeffect on growth of A. nigrocauda. Mainly considering the growth performance, itwas concluded that the suitable dietary lipid level for A. nigrocauda fingerlingshould be7.57%~8.49%.