白化牙鲆幼鱼与角叉菜和孔石莼混养的能量平衡和体色恢复率

Energy budgets and retrieval pigmentation in albino Japanese flounder (Paralichthys olivaceus) juveniles stocked with Ulva pertusavar and Pelvetua siliquosa

将体重为(5.04±2.14)g、体长为(8.15±2.84)cm的白化牙鲆Paralichthys olivaceus幼鱼饲养在容积38 L、底面直径17 cm的白色塑料桶中,放养密度为15尾/桶。试验共设7组,分别放入密度为0(对照组)、1、2、3 g/L的孔石莼Ulva pertusavar和3、5、7 g/L的角叉菜Pelvetua siliquosa,每组设3个重复,自然光照。30 d的生长试验表明,牙鲆与石莼混养能改善水质,促进牙鲆体色恢复。第二个阶段的试验,白化牙鲆仅与石莼混养,放养密度为10尾/桶。试验共设4组,每组放入石莼的密度(湿重)分别为4、3、2、0 g/L,记为H、I、J、K组,每组设3个重复。测定牙鲆的能量收支和体色恢复率(即试验结束和开始时白化鱼有眼侧正常体色的面积分别占试验结束和开始时有眼侧总面积的百分比之差)。经60 d的饲养,各组鱼的能量平衡式如下:H组100C=8.99F+5.66U+29.60R+46.33G(平衡率为90.58%);I组100C=7.20F+6.28U+33.20R+41.52G(平衡率为88.20%);J组100C=7.53F+7.13U+35.60R+36.62G(平衡率为86.88%);K组(对照组)100C=8.40F+7.04U+44.90R+29.91G(平衡率为90.25%),其中H、I、J 3个试验组鱼的生长能占同化能的比例分别比对照组的增加了16.42%、11.61%和6.71%;体色恢复率也显著高于对照组(P<0.05),依次为I组>J组>H组>K组(对照组)。

In the first trial, albino Japanese flounder Paralichthys olivaceus juveniles（5.04 ± 2.14）g in mean body weight） were stocked into 21 38 - L plastic aquaria at a rate of 15 fish per aquarium and polycultured with Ulva pertusavar and Pelvetua siliquosa at a rate of 0,1,2, 3 g/L and 3, 5, and 7 g/L, with triplication, respectively. It was found that Ulva pertusavar improved water quality and growth of juvenile flounder. Hence, in the second trial, albino Japanese flounder juveniles with same sizes were stocked into 12 38 - L plastic aquaria at a rate of 10 fish per aquarium and polycultured with Ulva pertusavar at a density of 4（ Group H） , 3 （Group I） , 2 （Group J） , 0 g/L（ Group K）with triplication for 60 days, respectively. The energy budgets and retrieval pigmentation rates （ a ratio of albino surface area on the ocular side to normal pigmentation surface area at the ocular side at the end of the experiments compared with that at the beginning of the experiments） of these juveniles were determined under these conditions. The energy budgets of the fish in different treatments were as the following： Group H 100C=8.99F＋5.66U＋29.60R＋46.33G; Group I 100C=7.20F＋6.28U＋33.20R＋41.52G; Group J 100C =7.53F ＋7.13U＋35.60R＋36.62G; Group K 100C=8.40F＋7.04U＋44.90R＋29.91G, where C = feed energy ; F = fecal energy ; U = urine energy ; R = metabolic energy ; G = growth energy, indicating that for growth energy in feed energy there were 16.42% , 11.61% and 6.71% higher in Group H, Group I and Group J than that in Group K, respectively. Retrieval pigmentation rates were found to be significantly higher in Group H, Group I and Group J than that in Group K and were ranged at the descendant order as： Group I 〉 Group J 〉 Group H 〉 Group K.