Study On Bacterial Flora With Early Life Stages Of The Grass Carp (Ctenopharyngodon Idellus)

The succession of bacterial flora in the early life stages(egg,larvae,juvenile and young) of grass carp(Ctenopharyngodon idellus) was invested.Meanwhile,the bacterial flora of water and food were also studied.At egg stage:The bacteria flora was detected at fertilizing(0.0 h after fertilizing),the cleavage period(2.0 h after fertilizing),the blastocyst stage(7.0 h after fertilizing),the organ differentiation period(15.5 h after fertilizing) and before hatching(23.5 h after fertilizing),respectively.The results showed that:1.The number of bacterial flora was increased with the development of eggs after fertilizing,the number was 1.24x10~1 cfu/egg at fertilizing,and it was increased to 1.41x10~5 cfu/egg before hatching.With the development of eggs,the predominant bacterial flora of eggs was Aeromonas,Enterobacteriaceae,Micrococcus and Corynebacterium,later,the predominant bacterial flora of eggs was Moraxella and Acinetobacter.2.The number of bacterial flora in water was stable,which was 1.05x10~4-3.85x10~4 cfu/mL.But the number was rapidly before hatching,which was 1.32x10~6 cfu/mL in water.The predominant bacteria flora in water was Aeromonas,Enterobacteriaceae and Moraxella.At larvae,juvenile and youny stege:The intestinal bacteria was detected at non-feeding stage,1d,3d,7d,14d,21d,28d,35d,49d,63d and 77d after feeding,respectively. The results showed that:1.The bacterial flora was not detected at non-feeding stage.The number of aerobic and facultative anaerobic,anaerobic intestinal bacteria was increased with the development of grass carp after feeding.After diet conversion,the number of intestinal aerobic facultative anaerobic bacteria was stable,but at 63d after feeding,the number of aerobic and facultative anaerobic intestinal bacteria in the group which was feeded with artificially formulated food group were slightly higher than that of duckweed(Spirodela polyrhiza) group.After diet conversion,the number of anaerobic intestinal bacteria continued to increase,at 49 d after first feeding,the number was stable,and it was not affected by different diets.The predominant aerobic and facultive anaerobic intestinal bacteria was Aeromonas,Enterobacteriaceae,Vibrio,Acinetobacter,Moraxella, Corynebacteriurn in the early development of grass carp.Form ld to 14d after first feeding,the composition species of aerobic and facultive anaerobic intestinal bacteria were gradually increased.After diet conversion,the composition proportion of aerobic and anaerobic intestinal bacteria was changed which was feeded with duckweed.The percentage of Moraxella and Acinetobacter was increased at first then decreased, Aeromonas and Enterobacteriaceae was inversely correlated.Fininly,the composition proprotion of aerobic and anaerobic intestinal bacteria was considerate to the group that was feeded artificially formulated food.The predominant facultive anaerobic intestinal bacteria was Bifidobacterium.2.The number of bacterial flora in water was relatively stable before and after diet conversion.After diet conversion,the number of bacteria in water was increased which was feeded with artificial diet,but it was stable which was feeded duckweed.During the early development of grass carp,the predominant aerobic and facultive anaerobic in water was Aeromonas,Enterobacteriaceae,Vibrio,Moraxella,Acinetobacter and Flavobacterium.After diet conversion,the composition of bacteria in water was changed, the proportion of Aeromonas,Enterobacteriaceae and Vibrio decreased,and the proportion of Moraxella,Acinetobacter and Flavobacterium increased.3.The bacteria number of zooZooplankton(mainly cladocera) was 1.6×10~7 cfu/g, and that of duckweed was 1.24×10~7 cfu/g.There was no bacterial detected in artificially formulated food.The predominant bacteria of Zooplankton was Aeromonas, Enterobacteriaceae,Vibrio,Corynebacterium,the predominant bacteria of duckweed was Enterobacteriaceae,Flavobacterium,Aeromonas,Acinetobacter,Moraxella.The bacterical flora of grass carp eggs was related to the bacterial flora in water,the intestinal bacterical flora of the early stages of grass carp was related to the bacterial flora of water and food.