Effects Of Different Oil-seeds On Growth, Physiological Function And The Composition Of Fatty Acids In Tissues And Organs Of Megalobrama Amblycephala

This experiment was conducted to investigate the effect of Megalobrama amblycephala fed the diets containing four different oil-seeds at dietary two lipid levels on the growth(survival rate, growth velocity, feed coefficient rate, physique and body index, Viscerosomatic index, composition of fish body),physiological function(lysozyme, LSZ; superoxide dismutase, SOD; aspartate transaminase, GOT; hemoglobin, Hb) and study on the correlation rate (CR) between fatty acid composition in tissues and organs and that of the feed. Four hundred and five M. amblycephala frys, weighing 9 g, were randomly assigned to nine dietary treatments at triplicates and each tank had fifteen fish. Two dietary lipid levels (1.5% and 3.0%) were tested. The control diet contained 1.5% soybean oil and the soybean oil was replaced by the inclusion of raw soybean, rapeseed, peanut or sunflower seed to obtain two lipid levels. The feeding trial lasted for 102 days.On the growth, the results showed that①at 1.5% lipid level, compared to the control group, specific growth rate (SGR) of the fish of raw soybean, peanut and sunflower seed groups increased by 11.54%, 14.42% and 11.54%, respectively; Protein efficiency ratio (PER) increased by 7.69%, 12.31% and 10.00%, respectively and feed conversion ratio (FCR) decreased by 11.19%, 12.64% and 6.86%, respectively.②at 3% lipid level, compared to the control group, the SGR of the fish of peanut group increased by 19.23%, the PER increased by 17.69% and the FCR decreased by 17.69%.③When the dietary lipid increased from 1.5% to 3.0%, SGR of peanut group increased from 1.19%·d-1 to 1.24%·d-1;PER increased from 1.46 to 1.53 and the FCR decreased from 2.42 to 2.28.④There were no significant different in condition factors, in muscle lipid and protein content of fish fed different diets. The fish fed soybean showed significantly lower body lipid content while higher protein content. Hepatopancreas lipid content was significantly lower and protein was significantly higher in the fish fed soybean meal diets at 3.0% dietary lipid. In physiological function, compared to control group, Hb and LSZ of serum and phlegm degraded, SOD of phlegm of rapeseed group and sunflower seed group; GOT of serum of all groups increased besides sunflower seed group, hepatopancreas was opposited. The correlation rate (CR) between fatty acid composition in tissues and organs and that of the feed showed that:①The correlation rate (CR) between fatty acid composition in organs and that in the feed grows along with the increased amount of lipid added to the feed, e.g. when soybean added up to 1.5% lipid oil, CRs are 0.81 (in muscle), 0.53(in hepatopancreas) and 0.83 (in kidney). Correspondingly in lipid content of 3.0%, CRs are 0.87 (in muscle), 0.59 (in hepatopancreas) and 0.90 (in kidney).②There are variations in the relationship between fatty acid composition in different organs and that in the feed. The coefficients in tissues and organs, including muscle, gut fat, cavity fat, gut, kidney and skin, exceed 0.80. However, the coefficients are relatively low in serum, hepatopancreas, spleen, heart, and cerebrum.③Compositions of fatty acids in these oil-seeds have varied effect on tissues and organs. Soybean oil, soybeans and sunflowers exhibit distant connection with fatty acid composition in tissues and organs. In contrast, remarkable effect is produced by rapeseeds and peanuts.④In terms of fatty acids in organs, C18:2n-6 of series n-6 diminishes in accord with the feed, with the increase ofγ-C_18:3n-6, C_20:2n-6, C_20:3n-6 and C_20:4n-6.These results indicated that①at the 1.5% lipid level, the growth of Megalobrama amblycephala of the soybean, peanut and sunflower seed groups were better than this of control group, and they can be used as the raw materials for feed;②When the lipid level increased from 1.5% to 3.0%, the growth of Megalobrama amblycephala of the peanut group was further enhanced, but that of the soybean and sunflower groups decreased, there was no significant change in the rapeseed group.③There have passive impact on the fish fed the diet added oil-seeds in immune function, hepatopancreas, hematopoiesis function.④There are variations in the relationship between fatty acid composition in different organs and that in the feed, and compositions of fatty acids in these oil-seeds have varied effect on tissues and organs; Fish is somewhat capable of converting fatty acids from the feed, which mainly rests on the conversion of series n-3and n-6 within the type.