Research Of Silkworm Pupa Oil Application In Tilapia (Oreochromis Niloticus) Feed

The experiment was conducted to study the feasibility of the application of silkworm pupal oil in tilapia(Oreochromis niloticus)feed.The relative content of unsaturated fatty acids in silkworm pupal oil was quite high,with a mass fraction of 61.5%.Silkworm pupal oil is rich in ?-linolenic acid that could derived for high unsaturated fatty acids in EPA(C20:5n-3)and DHA(C22:6n-3)and its have high value of development and utilization.In order to explore the feasibility of the application of silkworm pupa oil in GIFT Oreochromis niloticus feed,the following two aspects were studied: 1.Comparative study on effects of silkworm pupal oil and other six kinds of lipid on growth,body composition and lipid metabolism of GIFT Oreochromis niloticusSeven isonitrogenous and isolipidic diets were formulated by adding 5.0% silkworm pupal oil(SPO),marine fish oil(MFO),tilapia oil(TO),pork lard(PL),chicken oil(CO),linseed oil(LO)and soybean oil(SO),respectively,to the basal diet to feed tilapia [initial body weight(47.51±0.52)g].Each treatment contained three replicates with 20 fish per replicate and fish were fed for 56 days.The results showed that the final body weight,weight gain rate and specific growth rate of LO and SO groups were significantly higher than that of SPO and MFO groups,but showed no significant differences with that of TO,PL and CO groups.Feed conversion ratio of SPO group was significantly higher than that of other groups,except that of MFO group,while protein efficiency rate showed an opposite trend.Feed intake showed the lowest value in SPO group,and highest value in SO group.TO group presented the lowest viscerosomatic index,body length / body depth and intraperitoneal fat ratio and the highest condition factor.Hepatosomatic index in PL group was significantly higher than that of other groups except LO group.Intraperitoneal fat ratio in MFO group was significantly higher than that of other groups except CO group.Compared with the other groups,SPO could reduce the crude lipid in whole body lipid and tissue and triglyceride(TG),glucose and malonaldehyde contents in serum.MFO could reduce the crude lipid in whole body and enhance the acetyl-CoA carboxylase(ACC)activity in fish liver.PL groups presented lower TG and total cholesterol(TC)contents in serum and higher carnitine acyl transferase-I(CPT-I)and ACC activities in liver.The highest TG,TC,low density lipoprotein cholesterol(LDL-C)contents and aspartate transaminase activity were observed in serum of CO group.LO and SO could significantly increase the lipid retention ratio and crude lipid content in whole body and muscle.SO significantly increase the high density lipoprotein cholesterol(HDL-C)and reduced LDL-C and TC contents in serum.SPO,LO and SO,respectively,could significantly increase highly unsaturated fatty acids,?-linolenic acid and linoleic acid contents in fish muscle.In conclusion,although fish growth performance is decreased,SPO has advantages of decreasing body lipid,blood lipid and glucose,protecting fish health,optimizing muscle fatty acids composition.2.Effects of combination of silkworm pupa oil and soybean oil on growth,body composition and lipid metabolism of GIFT Oreochroms niloticus.Five disonitrogenous and isolipidic diets were formulated,based on either silkworm pupa oil or soybean oil,the total addition level was 5%.The configuration of silkworm pupa oil(soybean oil)levels were 5%(0%),3.75%(1.25%),2.5%(2.5%),1.25%(3.75%)and 0%(5%),respectively(SPO,SPO:SO 3:1,SPO:SO 2:2,SPO:SO1:3 and SO),to feed tilapia [initial body weight(48.07±0.23)g].Each treatment contained three replicates with 20 fish per replicate and fish were fed for 56 days.The results showed that: With the increase of the proportion of silkworm chrysalis oil and the decline of soybean oil,the final body weight,weight gain rate,specific growth rate,protein efficiency ratio and feeding amount initially increased initially and then decreased,and all got maximum at SPO:SO 3:1,and all got minimum at SPO,by contrast,feed coefficient showed downward trend.Body length / body depth and intestinal index initially increased and then decreased,and there was no significant difference in viscerosomatic index,hepatosomatic index and intestinal fat coefficient.The crude lipid content of whole body,liver and muscle initially increased and then stabilized,the ash of whole body initially increased initially and then decreased and then stabilized,the moisture of whole body initially decreased and then stabilized,while the moisture in liver was irregular.The deposition rate of dry matter,protein and ash in Tilapia increased initially and then decreased,while the lipid retention ratio increased initially and then stabilized.The content of linoleic acid in the muscle increased,and the content of linolenic acid and high unsaturated fatty acid decreased;Tilapia serum TG increased continuously,HDL-C and CPTI increased initially and then decreased,and all got the maximum chrysalis oil: soybean oil 2:2 group.LDL-C,ACC and GPT decreased initially and then increased,and all got minimum at silkworm pupa oil: soybean oil 3:1,MDA and alkaline phosphatase were increased initially and then decreased.The research revealed,silkworm chrysalis oil accounted for 50% to 75% of the combination of silkworm chrysalis oil and soybean oil,which has advantages of enhancing the growth performance of tilapia,promote the deposition efficiency of fish to feed dry matter,protein and minerals,protecting fish health.