养殖密度对珍珠龙胆石斑鱼行为活动 和生长性能的影响

Effects of stocking density on behavior and growth performance of Epinephelus fuscoguttatus ♀× Epinephelus lanceolatus ♂

  • 摘要: 目的研究不同养殖密度对珍珠龙胆石斑鱼摄食行为、生长及血液生化指标的影响,为工厂化养殖珍珠龙胆石斑鱼提供参考依据.方法在工厂化条件下,设60、100和140尾/m33种养殖密度,养殖周期50 d,记录珍珠龙胆石斑鱼的摄食行为,并测定其生长性能及血液生化指标.结果在摄食行为方面,随养殖时间的延长和养殖密度的增加,珍珠龙胆石斑幼鱼摄食形态基本遵循圆锥形—碗形—团形—平铺形的变化规律;随着养殖密度的增加,珍珠龙胆石斑鱼分布在上层摄食比例逐渐降低,对应的平均摄食比例分别为80.0%、72.0%和66.7%,其在摄食等级1所占比例也逐渐降低,分别为82.7%、73.3%和64.0%.在生长性能方面,珍珠龙胆石斑鱼的平均增重、日增重、饵料转化率和生长效率等4项指标随养殖密度的增加而逐渐下降,饵料系数则随养殖密度的增加呈上升趋势,组间差异均达显著水平(P<0.05,下同);体长、全长、增重率、增长率、特定生长率和存活率等6项指标受养殖密度的影响均未达显著水平(P>0.05,下同).在血液生化指标方面,随着养殖密度的增加,珍珠龙胆石斑鱼白细胞含量呈逐渐上升趋势,而葡萄糖含量无明显变化,组间差异均不显著.综合各项指标,以养殖密度为100尾/m3的效果最佳.结论养殖密度过低或过高均不利于珍珠龙胆石斑鱼生长,工厂化养殖珍珠龙胆石斑鱼的适宜密度为100尾/m3,既能保障其健康生长,降低生产成本,又可获得理想的经济效益.

     

    Abstract: ObjectiveEffects of stocking density on ingestion behavior, growth, blood physiological and biochemical indexes of Epinephelus fuscoguttatus♀×E. lanceolatus♂were evaluated to provide reference for its breeding under indus-trial conditions. MethodUnder industrial conditions, three stocking densities 60, 100 and 140 ind/m3 were set, and the breeding cycle was 50 d. Ingestion behavior of E. fuscoguttatus♀×E. lanceolatus♂ was recorded, and its growth perfor-mance and blood physiological and biochemical indexes were measured. ResultIn terms of ingestion behavior, as breeding cycle extended and stocking density increased, the ingestion patterns of juvenile E. fuscoguttatus♀×E. lanceolatus♂showed a certain regularity, and basically followed cone-calathiform-agglomeration-tiling type. With increase of stocking density, the proportion of E. fuscoguttatus♀×E. lanceolatus♂in upper layer of ingestion gradually reduced and the cor-responding average ingestion rates were 80.0%(60 ind/m3), 72.0%(100 ind/m3) and 66.7%(140 ind/m3). In addition, the proportion of ingestion level 1 also gradually reduced and the average proportions were 82.7%(60 ind/m3), 73.3%(100 ind/m3) and 64.0%(140 ind/m3). In growth performance, average weight gain, daily weight gain, feed conversion rate and growth efficiency declined with the increase of stocking density; feed coefficient increased as stocking density increased, the dif-ferences between groups were significant(P<0.05, the same below). But effects of stocking density on body length, whole length, weight gain rate, growth rate, specific growth rate and survival rate did not reach significant level(P>0.05, the same below). In terms of blood biochemical indicators, with the increase of stocking density, white blood cell content of E. fuscoguttatus♀×E. lanceolatus♂ rose, but glucose content remained stable. There was no significant difference between groups. Taking all the indxes into consideration, 100 ind/m3 was the optimal stocking density. ConclusionExcessively low density or high stocking density are not beneficial for growth of E. fuscoguttatus♀×E. lanceolatus♂, the optimum breeding density was 100 ind/m3 for its breeding under industrial conditions. This stocking density can ensure the healthy growth of E. fuscoguttatus♀×E. lanceolatus♂, reduce production costs, and obtain desired economic benefits.

     

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