| Generally agreed that with rapid expansion of aquaculture, raw materials like fish mealand fish oil from marine fisheries may not be able to sustain the needs of aquaculture in nottoo distant future.This is because the global demand for these raw materials for aquafeeds hasincreased steadily despite the static global production levels and may not be able to meet thedemand in the near future (FAO2006). Consequently, replacement of these popularly usedfeed ingredients in aquafeeds with economically viable and sustainable alternatives havebecome more than casual considerations. silkworm pupae,which includes high level ofprotein and lipids and has a good balance of all of the essential amino acids, has a greatpotentials in aquatic feed.The study was going to make efforts on the follow topics:(1) Effects of twotreating technology on quality of silkworm pupae meal;(2) Effect of silkworm pupaereplacement of fish meal on growth performance, biological parameters, body composition,serum biochemical indices and intestinal histological structure of Cyprinus carpio var.specularis fingerlings;(3) Effects of different dietary lipid sources in the silkworm pupa baseddiet for mirror carp (Cyprinus carpio var. specularis) on growth performance, bodycomposition and health status.The aim of the study was to offer theory basis and reference datasfor silkworm pupae utilizations in Cyprinus Carpio Var. Specularis diets. The experimentresults showed as follow:(1) The silkworm pupae meal of n-hexane defatted was odorless,decolorant,andvolume-weight, crude protein and ash was the highest,crude fat was the lowest(P<0.05).Though water boiled defatted SM was odorless,but it became more colorant. Then-hexane defatted significantly changed fatty acids composition of silkworm pupaemeal,though the water boiled changed little fatty acids composition. We found that differenttreating technology had different effects on amino acids composition of silkworm pupaemeal, they became close to FAO/WHO standard mode after defatted.(2) Fish meal (FM) group diet(100g/kg fish meal,0g/kg silkworm pupae, CP36.18%,EE5.18%) and silkworm pupae (SP) group diet (50g/kg fish meal,55g/kg silkworm pupae,CP35.38%, EE5.06%) were formulated to feed for mirror carp, Cyprinus carpio var.specularis fingerlings (initial body weight12.10±0.89g)(mean±S.D.) three times daily tovisual satiety in indoor circulating water system for61days.The results showed that growth performance, feed utilizition, biological parameters, chemical composition, serumbiochemical indices of the SP group and FM groups had no significant difference(P>0.05).The contents of Lys in whole body and Tyr in muscle of SP group were significantly lowerthan those in FM group(P<0.05). The content of C14:0, C16:1n-7and C18:1n-7in muscle ofSP group were significantly lower than that in FM group, that of C18:3n-3and Σn-3PUFA inmuscle of SP group were significantly higher than that in FM group(P<0.05). While thecontent of C18:3n-3and C22:5n-3in hepatopancreas of SP group was significantly higherthan that in FM group (P<0.05). Neither index of atherogenicity (IA) nor index ofthrombogenicity (IT) has significant difference in SP group and FM group. There are nosignificant difference in mucosa amount, mucosa height, mucosa width and submucosathickness of foregut and midgut, however the muscular coat thickness of foregut is significantlower in SP group than FM group (P<0.05).(3) Four isonitrogenous (36.5%crude protein), isolipidic (7%crude fat) experimentaldiets were formulated to contain2%soybean oil (SO), rapeseed oil (RO),fish oil (FO),1:1:1soybean-rapeseed-fish oil(MIX) in silkworm pupa based diet,respectively. Each diet was fedto triplicate groups of27mirror carp, Cyprinus carpio var. specularis (initialweight:10.70±0.70g) to apparent satiation three times a day for58-day in a recirculationsystem.The results showed that final weight and intestine length ratio was the highest in SO,the lowest in FO. Condition factor and intestine index in SO were significant higher than thatin FO (P<0.05).Hepatosomatic index was the highest in SO,followed FO and RO,the lowestin MIX. The effect of dietary lipid sources on the chemical composition of tissues wassignificant only for whole body and muscle,especially for the moisture and crude fat. Liverand muscle fatty acid composition for all treatments generally reflected the composition inthe diet. Hepatopancreas polyunsaturated fatty acid (PUFA) level was similar in SO andRO,which were significant higher than FO. Muscle PUFA level in SO was higher than that inFO, while Muscle HUFA in RO was higher than FO and MIX. No significant differencewere found in serum biochemical indices, except the GLU contents in RO was higher thanSO.Although there was no significant difference in serumT-SOD activity, GSH-XP activityin SO was the highest, AKP activity in FO was the lowest and MDA contents in SO waslower than FO and MIX. Hepatopancreas T-SOD activity in FO was the highest, AKPactivity in FO was higher than RO and MIX, GSH-XP activity in FO was higher than MIX.No significant difference was found in hepatopancreas MDA contents.Conclusion: silkworm pupae meal defatted with n-hexane has higher content of crudeprotein, lower content of crude fat and excellent fatty acids and amino acidcomposition,which can be propitious to application in feed fields; Silkworm pupae is an acceptable alternative animal protein source that can replace up to50%of fish meal proteinin diet without significant adverse influence on growth performance, biologicalparameters,commom body composition, serum biochemical indices and intestinalhealth,though it could affect tissue amino acids and fatty acids composition of Cyprinuscarpio var. specularis; The pupa fat in diet with the addition of soybean oil or rapeseed oilhad positive effects on growth performance, body composition and health status, while withthe addition of fish oil or mixed oil had negative effects. |
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