饲喂枯草芽孢对草鱼粪便、养殖水体中芽孢数量和水质的影响

Effect of dietary Bacillus subtilis Spores on water quality and the number of spores in the grass carp(Ctenopharyngodon idellus) faeces and water

分别在饲料中添加不同含量的枯草(Bacillus subtilis)芽孢(A组实测芽孢数量为2.6×107 cfu/g,B组为4.4×106 cfu/g,空白组为0),饲喂静水水族箱中100 g左右的草鱼(Ctenopharyngodon idellus)10 d,测定饲喂枯草芽孢后草鱼粪便、养殖水体中芽孢数量和水质的变化。结果表明:(1)9 d内,水体中芽孢数量A组和B组在前6 d时不断增加,在6 d时达到稳定,其中A组和B组稳定时的含量分别为2.22×106 cfu/g和3.98×105 cfu/g。(2)10 d内,草鱼粪便干物质中的芽孢数量与饲料中的枯草芽孢含量相比,A组和B组粪便中的枯草芽孢损失率分别为89.76%～90.71%和83.83%～86.84%。(3)草鱼饲喂枯草芽孢后,A组和B组粪便中排出的枯草芽孢对水体中亚硝酸盐和氨氮有降低的趋势,但各组之间差异不显著(P>0.05),对化学需氧量(COD)没有影响。

Ten days feeding experiment was conducted to investigate the effects of different levels of Bacillus subtilis spores supplement on water quality and the number of spores in the grass carp（Ctenopharyngodon idellus）faeces and water.The basal diet was applied as control,in which 2.6×107 cfu/g,4.4×106 cfu/g were added as tested diets A,B,respectively.Healthy grass carp（C.idellus）with an average intial body weight of 100 g were stocked randomly in each aquarium.The results showed that：（1）The number of spores in water of group A and B increased in the first 6 days,and stayed stable in 6-9 days which was 2.22×106 cfu/g in group A and 3.98×105 cfu/g in group B.（2） In 10 days,compared with B.subtilis spores in diet,the lose rate of B.subtulis spores in faeces（DM） of group A and B was 89.76%～90.71% and 83.83～86.84%,respectively.（3）After the grass carp was fed with B.subtilis spores,the faeces that contained B.subtilis spores had the trend to reduce the nitrite and ammonia content in water,but the differences among groups were not significant,and no effect can be found in COD.