| In order to explore the effect of different fermentation time on the nutrient content of bio-fermented feed and the effect of bio-fermented feed on the growth performance,digestion and immunity of fertility crucian carp,the determination of feed nutrients in different fermentation time and the effect of bio-fermented feed on growth performance,digestive enzyme and immune enzyme activity of fertility crucian carp were studied in this study.In the study,the fertility crucian carp with an average body weight of(15.13±1.51)g and body length of(8.19±0.59)cm,were randomly divided into 4 groups.The control group was group A,and the experimental group was group B,C,and D respectively.Each group had three replicates and 50 fish in each group.The group A,B,C and D were fed with biological fermented feed at different fermentation times(0 d,1 d,3 d and 5 d)for 28 d,respectively.During the experiment,the change of nutrient content of fermented feed and the changes of growth performance,digestive enzyme activity and immune enzyme activity of fertility crucian carp were measured,so as to determine the effects of bio-fermented feed on the growth,digestion and immune function of fertility crucian carp.The results showed as follows:After fermentation,compared with the unfermented group,the feed fermented for1 d had a golden color,aromatic taste and good texture,and the contesents of crude fat,crude ash and total amino acids were increased,but the differences were not significant.The counts of viable bacteria in the feed fermented group.The feed fermented for 5 d was brown,pungent and sour,and the quality was lower than that in the unfermented group.Bio-fermented feed with suitable fermentation time could increase weight gain rate of fertility crucian carp.The weight gain rate of fertility crucian carp in group B was significantly higher than that in the group A,which was 19.46% higher.The weight gain rate of fertility crucian carp in group C was 6.21% higher than that in thegroup A,but the difference was not significant.The weight gain rate of fertility crucian carp in group D was significantly lower than that in the group A,which decreased by 6.76%.There was no significant difference in the effect of bio-fermented feed on the activity of immune enzymes in fertility crucian carp.With the increase of fermentation time,the activity of amylase,trypsin and lipase in fertility crucian carp increased first and then decreased.As for group B,the content of amylase,trypsin and lipase were 40.43 U/mg,847.45 U/mg and 3.39 U/mg respectively,which were slightly higher than those in group A but had no significant difference.However,the activity of lipase and amylase in group C was higher than that in group A.The activity of lipase,amylase and trypsin group D was the lowest,which with content were1.92U/mg,39.08U/mg and 781.31U/mg,respectively.Bio-fermented feed could improve the nonspecific immunity enzyme activity of fertility crucian carp.The glutamate transaminase activity in group B,C and D of fertility crucian carp was significantly higher than that in group A while the superoxide dismutase activity was higher than that in group A but had no significant difference.The catalase activity of group C was slightly higher than that in group A,but the difference was not significant.The results showed that the bio-fermented feed with appropriate fermentation time,sensory evaluation and better feed quality could not only improve the nutritional composition of the feed,but also improve the growth performance of fertility crucian carp,and promote the growth obviously.Besides,the activity of digestive enzyme and immune enzyme of fertility crucian carp were also improved.In addition,the determination results of growth,digestion and immune indexes of fertility crucian carp also indicated that the appropriate fermentation time of bio-fermented feed was 1 day. |
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