Physiological And Biochemical Responses Of Olaquindox To Cyprinus Carpio L. And Its Residue In Tissues

It's well known that olaquindox poses double actions to animals. The positive effect is that it can be used in disease treatment and prevention (therapeutic and prophylactic uses), or can improve feed intake, growth rate, and feed conversion efficiency of several farm species fed continuously at low levels (sub-therapeutic use). On the other hand, it can result in toxicity to target animals with inappropriate use. So far most studies focused on livestock or fowls, however few investigations of olaquindox on fishes are reported, especially in toxicity to fishes. Hence, beforehand, an acute toxic test of olaquindox to fish was carried out, based on this, two feeding trials(in trial one, eight different doses of olaquindox in feeds were used, ig 0, 50, 100, 200, 400, 800, 1600 and 3200 mg/kg; except doses of 50 and 100 mg/kg, the remainders were used in trial two) were introduced to study the physiological and biochemical effects of olaquindox on young carp Cyprimts Carpio L. fed with feed containing different doses of olaquindox. And also the accumulation and residue in tissues of carp were investigated through the same two feeding trials.An acute toxicity test was conducted to investigate the toxicity of olaquindox to juvenile carp. Olaquindox was taken orally at the doses of 2000~10000mg/kg body weight and injected through abdominal cavity with 800~2441.4mg/kg body weight respectively. After 96h, any obvious toxic symptoms or death didn't occur on olaquindox-takening-orally carp. And median lethal dose to carp through abdominal injection was 1023mg/kg. The results showed that olaquindox toxicity to carp is very low. It's suggested that oral olaquindox with large dose is safe for carp.The influence of different concentrations of olaquindox (0, 200, 400, 800, 1600 and 3200mg/kg) in feed on growth performance and microflora in the intestine of carp was investigated in trial one. After the test finished, fish were weighed from each treatment group. Two fish sampled randomly from each group were used to determine the quantity and composition of their microflora in the fore, mid and hind gut at the end of this experiment. Olaquindox improved growth and feed efficiency of carp by 20.3%~32.9% and 14.5%~22.0% within doses of 200-800 mg-kg-1 of olaquindox as compared with control. At dose of 3200mg/kg, growth of carp depressed markedly, its growth decreased by 48.4%, and feed efficiency decreased by 54.9%.Microflora number in intestine of olaquindox-treated groups decreased to some extent when compared with control, which reduced by about an order of magnitude. The number of microflora in 3200 mg-kg-1 group reduced nearly for two orders of magnitude. The number of microflora reduced markedly in fore-gut from dose of 1600 mg-kg-1, in mid-gut from dose of-IV-200 mg-kg'1, in hind-gut at all olaquindox-treated group.There were seven varieties of dominant microflora detected in control, as also found in olaquindox-treated groups. But the composition of the microflora was not different among groups, in which Aeromonas and Acinetobacter changed obviously. The percentages of Aeromonas in corresponding total microflora of 1 1.06%, 11.74% and 7.41% at doses of 800, 1600 and 3200 mg-kg-1 were significantly lower than that in control. On the contrary, the percentages of 37.5%, 36.52% and 41.36% of Acinetobacter at doses of 800, 1600 and 3200 mg-kg- were all markedly higher than that in control. The results suggest that olaquindox can accelerate the growth of carp at appropriate dosage, but suppress its growth when the concentration of olaquindox was elevated to 3200mg/kg. The quantity and composition of microflora in the intestine in carp would change when fish are fed with feed containing different dosages of olaquindox.Oxygen consumption at the end of 50 days and 70 days was examined in trial one. The red blood cell number(RBC), hematocrit (PCV) and dyskaryosis in erythrocytes in carp were also determined after the trial finished. The results showed that oxygen consumption rates of fish treated with dose of 50~...