两种规格虹鳟胃排空模型和投喂频率的研究

Studies on Gastric Evacuation Rate and Feeding Frequency of Rainbow Trout(Oncorhynchus mykiss)in Two Sizes

为确定不同规格虹鳟(Oncorhynchus mykiss)幼鱼的最佳投喂频率,本研究采用胃含物分析法对两种规格(105.15±9.41)和(32.94±4.21)g虹鳟进行胃排空实验。两种规格虹鳟分别在饥饿72 h后饱食投喂一次,在投喂后第0、3、6、12、18、24、36和48小时提取胃含物。分别称量虹鳟胃含物的湿重和干重,并用线性模型、指数模型、平方根模型和逻辑斯蒂模型进行胃排空模式拟合。研究表明,利用胃含物干重进行虹鳟胃排空模式拟合效果较好,小规格和大规格虹鳟的胃排空模式分别符合指数模型和平方根模型。小规格虹鳟的胃排空速率高于大规格虹鳟。小规格和大规格虹鳟分别需要21.43和29.92 h达到80%胃排空。研究结果表明,对不同规格的虹鳟应采取不同的投喂频率,小规格和大规格虹鳟的投喂间隔应分别为20和30 h左右。本实验结果为智能化投喂系统提供了数学参考模型,为鱼类深远海养殖的早期大规格苗种培育提供了理论依据。

To determine the optimal feeding frequency of juvenile rainbow trout(Oncorhynchus mykiss)in different sizes,gastric evacuation experiment in rainbow trout in two sizes(small size(32.94±4.21)g and large size(105.15±9.41)g)was carried out by analyzing gastric contents.After 72 h of fasting,rainbow trout in two sizes were fed once.Subsequently,gastric content was extracted at 0,3,6,12,18,24,36,and 48 h after feeding,and wet mass and dry mass of gastric content were weighed.Linear regression model,exponential model,square root model,and logistic model were used to fit the gastric evacuation data.Results of this experiment indicated that gastric evacuation patterns have higher goodness-of-fit by using dry mass of gastric content compared to wet mass.The gastric evacuation patterns of small and large size rainbow trout were in accordance with exponential model and square root model,respectively.The gastric evacuation rate of rainbow trout in small size was higher than that in large size.Small and large size rainbow trout spent around 21.43 and 29.92 h in achieving 80%gastric evacuation,respectively.Therefore,feeding frequency should be modulated according to the size of rainbow trout.Feeding interval of about 20 and 30 h was the optimum for small and large size rainbow trout,respectively.We proposed a more reasonable feeding frequency of rainbow trout in intelligent feeding system,which provided a mathematical model for the intelligent feeding system,and a theoretical basis for the cultivation of large size fry in green salmonids for offshore farming industry.