Effects Of Prickly Ash Seed Powder And Its Oil On The Growth,Body Composition And Lipid Metabolism Of Grass Carp,Ctenopharygodon Idellus

As the main by-product of the production of Zanthoxylum bungeanum,prickly ash seed(PAS)has rich resources in our country,which is rich in a variety of nutrients and biologically active ingredients,which is a potential source of fat and protein source;and the prickly ash seed oil(PASO)is rich in polyunsaturated fatty acids(PUFA),which has certain regulatory effect on lipid metabolism.This study took grass carp as the research object to estimate the effects of PAS powder on the growth,body composition and lipid metabolism of grass carp juveniles,and explored the control effect of PASO on lipid accumulation of liver in grass carp.The study will provide a certain theoretical reference,and provide part of the theoretical basis for the high-value utilization of PAS.Trial 1 Formulate five groups of practical feeds for grass carp(33% protein and5% fat),and added 0%(Ⅰ),2.5%(Ⅱ),5.0%(Ⅲ),7.5%(Ⅳ)and 10%(Ⅴ)PAS powder respectively.Five kinds of equal nitrogen and energy feed is made.Total of 270 juvenile grass carp(9.21±1.20g)were selected and randomly divided into five groups,three repeats per group,18 fishes for each repeat.A 56-day feeding trial was conducted.The results:(1)Compared with group Ⅰ,the growth performance and biological characteristics of grass carp in the treatment group were not significantly different(P>0.05);the RIL of group V was significantly higher than that of groups Ⅱ and Ⅲ,and the VSI was significantly higher in group II(P<0.05);(2)The crude protein content of hepatopancreas in group V increased while the crude fat content was significantly decreased(P<0.05),the crude fat content of muscle in group Ⅰ was significantly higher than the content of the other four groups(P<0.05),the crude fat content of whole fish in group Ⅳ and group Ⅴ was significantly higher than the content in group Ⅱ and Ⅲ(P<0.05);no significant difference was founded in ash content among the groups(P>0.05);(3)In the hepatopancreas of groups Ⅲ and Ⅳ,the contents of linoleic acid and linolenic acid were significantly higher than the contents in group Ⅰ,and the proportion of DHA and n-3/n-6 PUFA in group Ⅲ were significantly higher than the proportion in group Ⅰ(P<0.05);The trend of linoleic acid and linolenic acid in IPF is opposite: the content of linoleic acid decreases with the increased level of PAS,and the content of linolenic acid increases accordingly.Significant differences appear in group Ⅲ,Ⅳ andⅤ;The n-3 PUFA content and n-3/n-6 PUFA content of group Ⅲ,Ⅳ and Ⅴ were significantly higher than group Ⅰ and Ⅱ(P<0.05);the content of linolenic acid in muscle increased with the addition of PAS,and group Ⅰ was significantly lower than group Ⅴ(P<0.05);The proportion of n-3PUFA and n-3/n-6 PUFA also increased with the level of prickly ash seed powder,but it was not significant(P>0.05);(4)As the level of PAS powder increased,the degree of vacuolization of hepatopancreas gradually decreased,and the arrangement of hepatocytes became denser.In groupⅤ,the degree of vacuolation of hepatopancreas was the lowest;the area of adipocytes in IPF in group IV was significantly smaller;(5)In hepatopancreas,the m RNA expression levels of lipid synthesis-related genes DGAT-1,PPARγ,and FAS were significantly down-regulated in group IV,group IV and Ⅴ,and group Ⅲ,IV and Ⅴ,respectively(P<0.05),and the m RNA expression level of lipid hydrolysis-related genes PPARα and CPT-1 in group III was significantly raised and higher than group Ⅰ and other three groups(P<0.05).The above results show that adding proper amount of PAS powder to grass carp feed can significantly decrease the accumulation of lipids in fish bodies.In addition,it can also save soybean oil to reduce feed costs,and has no negative impact on the health of grass carp.The optimum amount of PAS powder in grass carp feed is7.5%.Trial 2 At 4%(basic level)and 8%(high level)oil levels,PASO was used in the feed,and formulated into basic soybean oil group(SO)and basic PAO group(PASO),high-fat soybean oil group(HSO)and high-fat PASO group(HPASO)4 groups of equal nitrogen feed,the protein level is 32%.216 juvenile grass carp(9.43±0.82 g)were selected and randomly divided into four groups,three repeats per group,18 fishes for each repeat.A 56-day breeding experiment was conducted.The results showed that:(1)The VSI of HSO and HPASO was significantly higher than the VSI of SO(P<0.05);(2)The crude fat content of hepatopancreas in HSO and HPASO was significantly higher than the content of SO and PASO,The crude fat content in muscle of HSO was significantly higher than the other three groups(P<0.05);(3)The content of linolenic acid in PASO/HPASO in the hepatopancreas was higher than the content in SO/HSO,even though the difference was not significant(P>0.05);The proportion of n-6PUFA of PASO was significantly lower than the proportion of SO,and n-3/n-6 PUFA was significantly raised compared to SO(P<0.05);the content of linolenic acid in PASO/HPASO in IPF was higher than that of SO/HSO and was significant different in the basic groups(P<0.05);the n-6PUFA content in the PASO/HPASO is lower than SO/HSO and the n-3PUFA content is higher than SO/HSO,but no significant difference is founded(P>0.05),in PASO n-3/n-6 PUFA is significant higher than SO(P<0.05);linolenic acid content in HPASO was significantly higher than HSO(P<0.05)in muscle,n-6PUFA content in PASO/HPASO was lower than SO/HSO,in PASO n-3/n-6 PUFA was higher than SO;(4)In comparison with SO,liver cells in HSO had more obvious fat infiltration and nuclear deviation,and the degree of fibrosis also increased,the symptoms were improved in PASO/HPASO;the adipose cell area in PASO in the IPF was smaller as a whole;(5)In comparison with SO,PASO m RNA expression levels of the transcription factors PPARγ,SREBP1 and CEBPα of lipid synthesis-related genes in the hepatopancreas were significantly down-regulated(P<0.05);the m RNA expression levels of lipid decomposition genes PPARɑ and CPT-1 were significantly up-regulated in PASO(P<0.05).According to the results,using of PASO in the grass carp feed has no adverse effect on the growth performance of grass carp,and when the feed lipid level is4%,PASO can improve the fatty acid composition of the fish body and reduce the lipid accumulation of body and tissues.But when the feed lipid level is 8%,it has no obvious improvement effect on the lipid accumulation of liver in grass carp.In summary,the two application forms of PAS powder and PASO in grass carp feed have similar effects.They can both regulate the lipid metabolism of fish bodies,reduce lipid accumulation,and have no negative impact on the growth of grass carp.The optimal addition ratio of PAS power in grass carp feed is 5%-7.5%.The PASO can decrease the lipid accumulation of fish body at the basic lipid level,but it has no obvious improvement effect on lipid accumulation of liver in grass carp at high-fat conditions.