Effects Of Amino Acid Chelates On Growth,Liver And Intestinal Health And Immunity Of Juvenile Grass Carp(Ctenopharyngodon Idellus)

In order to study the effects of amino acid trace element chelates on the growth performance and liver and intestine health of grass carp(Ctenopharyngodon idellus),and determine the optimal replacement level of amino acid trace element chelates in grass carp feed compared with 100 % inorganic trace element chelates,the between the two in grass carp feed were compared.In this study,the juvenile grass carp with initial body weight of(40.05 ±0.05)g was used as the research object,and the basic diet without trace elements was designed as the control group(CON).Based on the commercial trace element formula,the inorganic trace element formula was designed,including Fe,Cu,Mn,Zn and other elements(IT100).At the same time,amino acid trace element chelates were used to replace 100 % of inorganic trace elements(OT25,OT50,OT75 and OT100)by 25 %,50 %,75 % and 100 %,and the organic trace element formula was designed.Six isonitrogenous and isoenergetic diets were formulated with three replicates per group.The experiment was conducted in a pond cage(1.5m × 2.0 m × 1.5 m)for 8 weeks.The results are as follows:1.Effects of amino acid trace element chelates on grass carp growth,trace element deposition and serum biochemistryCompared with the CON group,the weight gain rate of OT75 group was significantly increased,and the feed coefficient was significantly decreased.With the increase of the proportion of amino acid chelates replacing 100 % inorganic trace elements,the weight gain rate increased first and then decreased,and the OT50 group reached the growth effect of IT00 group.According to the quadratic regression equation,the amount of trace element deposition in the spine of grass carp reached the level of IT100 group at the addition level of Cu 67.53 %,Fe 58.22 %,Zn 58.68 % and Mn 56.07 %,respectively.When the replacement content of amino acid trace element chelate was more than 75 %,the trace element deposition increased significantly.With the increase of amino acid trace element chelate levels,the intestinal amylase,trypsin and lipase activities of juvenile grass carp increased first and then decreased,and the highest in OT75 group.The addition of amino acid trace elements had no significant effect on the composition of grass carp.With the increase in the addition level of amino acid trace element chelates,the levels of serum TG,T-CHO,LDL-C,BUN,GPT and GOT in grass carp showed a downward trend,and were the lowest in the OT100 group and significantly lower than those in the IT100 group,while the levels of C3,ACP and HDL-C were the opposite,and were the highest in the OT100 group and significantly higher than those in the IT100 group.2.Effect of amino acid trace elements on liver and intestine health of grass carpThe levels of GPx,GSH,CAT and SOD in hepatopancreas of grass carp increased with the increase of amino acid trace element levels,and increased significantly in OT100 group,which was significantly higher than that in IT100 group.The change trend of MDA content was opposite,and decreased significantly in OT100 group,which was significantly lower than that in IT100 group.With the increase in the addition level of amino acid trace element group,the morphology,abundance of hepatic sinusoid and arrangement of hepatic cord of grass carp tended to be normal.With the increase in the addition level of amino acid trace elements,the intestinal villus height,muscular thickness and goblet cell number of grass carp showed a trend of first increase and then decrease,and significantly increased in the OT75 group.Compared with the IT100 group,the intestinal villus height of OT100 group was significantly increased,and the muscular thickness and goblet cell number had no significant change.With the increase of amino acid trace element chelate concentration,the relative expression of occludin,claudin12,zo-1 and zo-2 genes in the intestine of grass carp increased first and then decreased,and it was significantly up-regulated in OT75 group.The relative expression of il-1β and il-6 was opposite,and it was significantly down-regulated in OT75 group.In addition,compared with the IT100 group,there was no significant difference in the expression levels of occludin,claudin12,zo-1,zo-2,il-1β and il-6 related genes in the intestinal tract of grass carp in the OT100 group.In summary,the appropriate concentration of amino acid trace element chelates(Fe,Cu,Mn,Zn)instead of inorganic trace elements can improve the growth performance and digestion and absorption ability of grass carp,improve the intestinal tissue structure,regulate the expression of intestinal tight junction proteins and intestinal cytokines,maintain the intestinal immune barrier function,improve the antioxidant capacity of liver and pancreas of grass carp,and maintain the health of liver and pancreas.Compared with inorganic trace elements,amino acid trace elements can improve the utilization efficiency of trace elements in grass carp,effectively promote the growth of grass carp and improve the health of liver and intestines of grass carp,and the growth effect of 100 % inorganic trace elements was achieved when the addition of amino acid trace element chelate was 50 %.Based on the quadratic curve model of weight gain rate,the suitable concentration of amino acid trace element chelate as a whole in trace element additives was 79.37 %.At the same time,the quadratic curve model of single element deposition in amino acid trace element chelates of grass carp spine was compared with inorganic trace elements.Cu,Fe,Zn and Mn reached 100 % titer of inorganic trace elements at 67.53 %,58.22 %,58.68 % and 56.07 %,respectively.