日光照周期对大菱鲆幼鱼摄食、消化酶活力与血清激素含量的影响
EFFECTS OF DAILY PHOTOPERIOD ON FEED CONSUMPTION, DIGESTIVE ENZYME ACTIVITIES AND BLOOD HORMONE OF TURBOT SCOPHTHALMUS MAXIMUS L. JUVENILES
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摘要: 研究了4种光照周期24L﹕0D(D1)、16L﹕8D(D2)、8L﹕16D(D3)和0L﹕24D(D4)对体重(30.5±2.0) g大菱鲆Scophthalmus maximus L.幼鱼20h (8:00am—4:00am)内摄食、消化酶活力、血清激素含量的影响。结果显示: (1)实验鱼的摄食率随光照时间的缩短而降低; D1组实验鱼每隔8h出现摄食高峰, 其他组均在8:00am及4:00pm出现摄食高峰。(2)D1、D2和D3组在12:00am和8:00pm出现肠道蛋白酶及淀粉酶活力峰值, 脂肪酶活力显著高于D4组(P<0.05)。(3)各组8:00am至8:00pm生长激素(GH)含量无显著变化, D1组4:00am时显著高于其他组(P<0.05), D4组0:00am及4:00am显著低于其他组(P<0.05); D1、D2和D3组初次摄食8h内皮质醇(COR)含量无显著变化, 8h后先升高后降低, D4组COR含量先升高后降低, 8:00pm时达到最高; D1和D2组0:00am时去甲肾上腺素(NE)含量显著高于其他组(P<0.05), D4组8:00pm时显著低于其他组(P<0.05); D2组8:00am及12:00am时三碘甲状原氨酸(T3)含量显著高于其他组(P<0.05), D4组8:00pm时显著低于其他组, 0:00am时显著高于其他组(P<0.05), D2和D3组4:00am显著低于D1和D4组(P<0.05), 各组T3最高值均出现在8:00pm。在实验条件下, 光照周期影响了大菱鲆幼鱼摄食、消化酶活力及血清激素含量。在此光照强度下, 大菱鲆养殖中以8—16h光照周期、日投喂2次为宜。Abstract: This study was conducted to investigate the effects of 4 kinds 24L﹕0D (D1), 16L﹕8D (D2), 8L﹕16D (D3), 0L﹕24D (D4) of photoperiods on feed consumption, digestive enzyme activities and blood hormone of turbotScophthalmus maximus L. juveniles with initial body weight of (30.5±2.0) g in 20 hours (8:00am—4:00am). The results showed that the feed rate decreased with the shorten of illumination time, and feeding peak in D1 group appeared every 8h, meanwhile others appeared at 8:00am and 4:00pm. Activities of protease and amylase of former 3 groups were appeared spike at 12:00am and 8:00pm, and lipase was significantly higher than that of the D4 group. There were no difference of GH contents from 8:00am to 8:00pm among all groups, and D1 group at 4:00am was significantly higher than others, but D4 group was significantly lower than others from 0:00am to 4:00am. COR contents of D1, D2 and D3 groups were not significant difference in 8h after first feeding, and then increased firstly and decreased afterwards; D4 group reached the maximum level at 8:00pm. NE content of D1 and D2 groups were significantly higher than that of the others at 0:00am, meanwhile D4 group was significantly lower than others at 8:00pm. T3 content of D2 group was significantly higher than that of the other groups at 8:00am and 12:00am; D4 group was lower at 8:00pm, and higher at 0:00am than others; D2 and D3 group were lower than those of D1 and D4 group at 4:00am; The highest values of T3 of all groups were appeared at 8:00pm. These results demonstrated that feed intake, digestive enzyme activities and serum hormone contents of turbot juvenile were affected by photoperiod under current experimental conditions. 8—16 lighting period and feed twice daily would be recommended for turbot culture under this intensity of illumination.