Studies On The Utilization Of Dietary Lipid In Innovate Pompano (Trachinotus Ovatus)

The present study was conducted to investigate the influence of lard,fish oil and mixed oil (1:1 of fish oil and lard) on the growth,physiological functions and fatty acid composition of the body in the conditions of 2% and 4% and lipid-lowering factor (compound carnitine,bile acid) on innovate pompano.525 innovate pompano (initial body weight 50.3g) were selected and distributed randomly into a system of 21 cages (1m length×1m width×2m high) with 25 fish per cage. The 7 experimental diets contained 43% crude protein and 6.95% to 9.62% crude lipid were fed to the fish with 3 replicate for 56 days.The main results were shown as follows:①Growth performance and biochemical parameters of innovate pompano fed diets containing different oil source.Compared 2% fish oil group (P2) and 2% lard group (P3),4% fish oil group (P4) with 4% lard group (P5),we found no significant differences (P>0.05) in specific growth rate,feed efficiency,protein efficiency and the levels of plasma total cholesterol (CH), triglyceride (TG),high density lipoprotein (HDL-C),low density lipoprotein (LDL- C) (P>0.05);Between mixed oil group (P1),4% fish oil group (P4) and 4% lard group (P5),we found no significant differences (P>0.05) in specific growth rate,feed efficiency, protein efficiency.The levels of CH,TG and LDL-C of serum were also not signify- cantly affected.The results suggested that in order to save the cost of feed,Lard can be used as a substitute for fish oil in diets of innovate pompano without affecting their growth performance.②Growth performance and biochemical parameters of innovate pompano fed diets reduced 3% import fishmeal and increased 2% lipid with the same protein percent.Compared 2% fish oil,35% fish meal group (P2) with 4% fish oil,32% fish meal group (P4),the specific growth rate of (P2) group was higher 0.06% than (P4) group, there was no significant difference (P>0.05).The feed conversion ratio significantly reduced by 0.18% and the protein efficiency ratio significantly increased by 14.87% (P<0.05).The T-SOD activity in mucus, liver and serum respectively significantly increased by 10.34,61.98 and 36.26.The liver GOT activity significantly increased by 173.14 (P<0.05).The serum HDL-C content significantly increased by 0.26 (P<0.05). The specific growth rate of (P3) group was higher than (P5) group by 0.10% without significant difference (P>0.05).The feed conversion ratio significantly reduced by 0.21% and the protein efficiency ratio significantly increased by 14.74% (P<0.05).In physiological indicators:T-SOD activity in liver and serum significantly increased by 16.79 and 9.22.The GOT activity in liver significantly increased by 142.04 (P<0.05).The results suggested that innovate pompano grew better fed the diets with high level import fish meal and low level lipid than the diets with low level import fish meal and high level lipid.It showed that the innovate pompano have a stronger demanded on high-quality protein source for instance fishmeal and have a stronger digestion and absorption ablity.③Growth performance and biochemical parameters of innovate pompano fed diets with anti-fat factors.Compared 4% fish oil and anti-fat factor added group (P7) with 4% fish oil group (P4), 4% lard group with the anti-fat factor added (P6) with 4% lard group (P5),to add the anti-fat factors,no significant differences were found in specific growth rate,feed efficiency, protein efficiency of the fish oil group (P>0.05);no significant differences were found in specific growth rate of the lard group (P>0.05),but the feed efficiency and protein efficiency were found significant differences (P<0.05).How- ever,they can enhance the mucus LSZ activity,the liver T-SOD activity,liver GOT activity,improve the metabolism of body lipid and protect the liver of Trachinotus ovatus.It played an important role in improving immune response and disease resistance.It is a good measure to add composite Carnitine 220 mg/kg and bile acid 100 mg/kg to the diet of Trachinotus ovatus to prevent the disease such as fatty Liver or poor disease resistance caused by high-energy and high-protein diet.④Tissue fatty acid profileDiet is the most important factor that affects the fatty acid composition of fish. Under the premise of dfferent fat sources,the feed added lard had a greater impact on relevance;with the rise of the adding level,The relevance of fatty acid composition of body and feed in lard group had increased but decreased in fish oil group(except for skin and muscle);Fatty acid composition of different tissues and organs affected by the fatty acid composition and feed have a certain degree of difference.Muscles, intestinal fat,intestine,skin,heart and brain were greater affected by fatty acids composition,and had a stronger correlation with feed fatty acid composition.But the effects of fatty acids in liver,spleenis relatively small,and had a smaller correlation with feed fatty acid composition.Both the content of n-3 PUFA (the majority of tissues) and n-6 PUFA (all tissues and organs) were less than the feed group,the reduction of n-3 PUFA is mainly due to the decreasing content ofα-C_18:3n-3 and C_22:6n-3,the reduction of n-6 PUFA is mainly due to the decreasing content of C_18:2n-6. And most of the increasing types of fatty acids in various tissues and organs were C_20:5n-3 and C_20:4n-6, i.e. fish can lengthened and desaturaseα-C_18:3n-3 and C_18:2n-6 into fatty acids such as C_20:5n-3 and C_20:4n-6.It indicated that fish have some certain capacity on conversion of different fatty acids,which is mainly from n-3 series and n-6 series into the n-3,n-6 high unsaturated fatty acids in the body.Further more,the highest content of C_16:0 and C_18:1n-9 was observed in various of tissues and organs of Trachinotus ovatus,it indicated that these fatty acids played an important role in the structure and physiological function in the tissue cells.