| Epinephelus moara?×Epinephelus lanceolatus?(hereinafter referred to as Yunlong) and Epinephelus coioides?×Epinephelus lanceolatus?( hereinafter referred to as Green Arowana) Epinephelus fuscoguttatus ?× Epinephelus lanceolatus ?(hereinafter referred to as Pearl Gentian) were used to study the effect of high and low temperature on resistance and serum biochemical parameters variation of hybrid groupers. We detected the semi-lethal temperature of Pearl Gentian, Green Arowana, Oplegnathus punctatus and Yunlong, in order to provide theoretical basis for the epinephelus healthy aquaculture in high temperature and low temperature environment. We also detected the sex steroid hormone during the parent epinephelus radiatus breeding time via temperature adjusting and controlling and nutrient enhancer in order to provide help for improving the reproductive capacity of parent.(1) The effect of temperature adjusting and controlling and nutrient enhancer on parent Epinephelus moaraIn this study, we selected 240 Epinephelus moara as research objects which are healthy and fit, grossness good, the average weight of 5.2±0.15 kilogram, and the average body length of 75±0.6 centimeter.We began to heat up the temperature via regulation from March, and we ensured adequate illumination and fortified feeding for them during heating period. The results showed that, the broodstock gonadal developed well and the hormone levels were normal by temperature adjusting and controlling and nutrient enhancer. The hormone levels of nutritional supplements group were much more higher than the control group?s.(2) The effect of high temperature on hybrid grouperswe chose the hybrid of Epinephelus Pearl Gentian, Epinephelus Yunlong, and Epinephelus Green Arowana as research objects and the experiment was setted up four temperature gradient including 25 29? ?,33 and 36? ?. The fishes were treated at a heating rate of 1 / d starting ?from 25 during high temperature stress observation experiment. At different time we detected ?the serum biochemical indicators and metabolic enzyme activities of Epinephelus Yunlong, and Epinephelus Green Arowana. The results indicated the semi-lethal temperature of Yunlong, Green Arowana and Pearl Gentian were 37?, 38 ?and 39?, respectively. For the Green Arowana with the increasement of stress strength and time in the high temperature compulsive experiments, the trend of serum triglycerides(TG) content and serum glucose(GLU) content were increased significantly, and serum creatinine(CREA) content and total cholesterol(T-CHO) content were decreased before increasing. The trend of serum superoxide dismutase(SOD) activity, seruglutamic-oxaloacetic transaminase(GOT) activity and serum acid phosphatase(ACP) activity were upward as stress continues, while the trend of serum glutamate pyruvate transaminase(GPT) activity, serum alkaline phosphatase(AKP) activity and serum catalase(CAT) activity were fluctuated. For the Pearl Gentian with the increasement of stress strength and time in the high temperature compulsive experiments, the trend of serum glucose(GLU) content and serum total cholesterol(T-CHO) content were upward as stress continues. The trend of serum triglycerides(TG) content and serum creatinine(CREA) content were increased before decreasing. The trend of serum glutamic-oxaloacetic transaminase(GOT) activity, serum alkaline phosphatase(AKP) activity and serum acid phosphatase(ACP) activity were decreased as stress continues. The trend of serum glutamate pyruvate transaminase(GPT) activity, serum superoxide dismutase(SOD) activity and serum catalase(CAT) activity were fluctuated.(3) The effect of low temperature on hybrid grouperswe chose the hybrid of Epinephelus Pearl Gentian, Epinephelus Yunlong, and Epinephelus Green Arowana as research objects in this study.The low temperature compulsive experiments was setted up five temperature gradient including 20(served as control)?,16?,15?,13 and ?10?, starting with 20?, and the rate of temperature fall was 1?/d. These three Epinephelus hybrids were observed and recorded survival rate and the Yunlong was detected serum biochemical indicators and metabolic enzyme activities during the experiment. As the results showed, the semi-lethal temperature of Pearl Gentian, Green Arowana, Oplegnathus punctatus and Yunlong were 11?, 9.5?, 9 and 8? ?, respectively. The trends of serum creatinine(CREA) content and total cholesterol(T-CHO) were decreased before increasing with increase of stress strength and time in the low temperature compulsive experiments. The trend of serum triglycerides(TG) content fluctuated and there were significant differences at 15 ?and 10 ?comparing with the control groups(P<0.05). The trend of serum glucose(GLU) content varied with the low temperature and there were significant differences at 16 and 13? ?comparing with the control groups(P<0.05). The trend of serum alkaline phosphatase(AKP) content was increased slightly and the other groups had no significant differences comparing with the control groups(P?0.05). The trend of serum catalase(CAT) activity fluctuated and there were significant differences at 16?, 15 ?and 10 ?comparing with the control groups(P<0.05). The trend of serum glutamic-oxaloacetic transaminase(GOT) activity had a slightly higher than the control groups(P?0.05). The trend of serum glutamate pyruvate transaminase(GPT) activity increased before decreasing with increase of stress strength and time in the low temperature compulsive experiments and there were significant differences 16 ?and 15 ?comparing with the control groups(P<0.05). As a result, Yunlong has the lowest temperature resistant compared with the other two hybrids. The low temperature could impair immunity and antioxidant capacity of juvenile fish and it is necessary to reduce low temperature compulsive intensity and shorten low temperature compulsive time during actual production. |
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