Effects Of Fermented Grain Protein On The Growth,the Digestive Enzymes Activity And Digestive System Histology Of Carassius Auratus Gibelio

A 90d growth trial was conducted to evaluate the effect of the dietary fermented grain protein (FGP) for Carassius auratus gibelio.The control diet contained 5% fish meal, the blank diet contained 0% FM and 0% FGP, whereas the other six diets, Group FGP₂ to FGP₁₂, were fish meal free diets, directly contained 2%, 4%, 6%, 8%, 10% and 12% of the FGP respectively.This growth trial determined the growth performance, apparent digestibility, body composition, activities of intestinal and liver digestive enzyme, and the structure of foregut.The main results were shown as follows:1. The weight gain,the specific growth rate (SGR)and protein efficiency ratio of fish fed FGP diets (group FGP₂ to FGP₁₂) were higher than those fed FM diet, but had no significant difference(P>0.05).The fish in Group FGP₁₂ showed the highest weight gain and SGR.2. Feed coefficient in blank group showed higest in all groups (P<0.05).The feed coefficient in group FGP₁0 and FGP₁₂ were significantly lower than that in control group (P<0.05).3. Compared with the control diet,experiment groups (FGP₂ FGP₁₂) gave slightly higher apparent digestibility for dry matter,crude protein and crude ash, but not significantly different(P>0.05).There is no significant difference between each group about the apparent digestibility of crude fat(P>0.05) . The apparent digestibility of phosphorus was significant higher for fish fed FGP groups (FGP₄ FGP₁₂) compared with those fed FM diet (P<0.05).The apparent digestibility of phosphorus enhanced with the increase of FGP content in diets from 2% to 12% (FGP₂ FGP₁₂) and so as increased calcium dihydrogen phosphate.4. The protease of intestine in gibel carp fed with FGP group has no significant difference with the control group and the blank group(P>0.05),but the protease activities of liver significant higher than the blank group (P<0.05).The amylase activities of intestine in gibel carp fed with FGP group has no significant difference with the control group and the blank group(P>0.05),but the amylase activities of liver slightly lower than the control group(P>0.05).5.The fermented grain protein has no effect on the crude protein,crude fat, crude ash,water and phosphorus in the body of gibel carp(P>0.05),the crude ash and phosphorus in the body of gibel carp fed with fermented grain protein showed higher than the fish fed with the control group (P>0.05),but crude fat in the body of gibel carp fed with fermented grain protein showed lower than the fish fed with the control group(P>0.05),all of them has no significant different.6.Fermented grain protein had no damage to the structure of foregut,it even promoted the function of intestine,the numbers of goblet cell in the fish fed with fermented grain protein were more than the blank group(P<0.05),but has no significant difference with the control group(P>0.05);the height of plicamucosa enhanced with the increased fermented grain protein content in diet 12% fermented grain protein group is 85.18μm higher than the blank group,and 32.68μm higher than the control group,but 4%¹2% fermented grain protein group has no significant difference than the control group and blank group(P>0.05).The 6% fermented grain protein group has thicker circular muscle layer than the blank group significantly,the other fermented grain protein group has thicker circular muscle than the blank group,but no significant difference . The numbers of plicamucosa,thickness of longitudinal muscle layer and the width of plicamucosa have no difference between with each group(P>0.05).