Dataset on body weight and length of rainbow trout, Oncorhynchus mykiss, fed with dihydroquercetin, arabinogalactan or a mixture of both in an aquaria experiment

The use of natural dietary supplements in aquaculture has received a great deal of attention in recent years. This article provides data describing body weight and length of rainbow trout juveniles fed with natural dietary supplements dihydroquercetin, arabinogalactan or a mixture of both in an aquaria experiment. Before feeding trial, rainbow trout were tagged to identify individuals. Fish grown in tanks were fed one of four diets in duplicate: a basal diet without any supplements (control diet) or a basal diet supplemented with dihydroquercetin (experimental diet 1), arabinogalactan (experimental diet 2) or a mixture of both (experimental diet 3). Our dataset could be used to evaluate the effect of dihydroquercetin, arabinogalactan or a mixture of both on the growth performance of cultivated rainbow trout.


Specifications
Aquatic Science Specific subject area Aquaculture nutrition, growth performance of cultivated fish Type of data Table and Figure  How data were acquired Rainbow trout body weight and length were measured with a digital balance (accuracy: 0.01 g; model SPX2202, OHAUS Corporation, USA) and a 300 mm liquid crystal display (LCD) digital Vernier caliper (accuracy: 0.01 cm; CHIZ, Russia), respectively. Data were analyzed with the lmer function from the lme4 package for R.

Data format
Raw Analyzed Parameters for data collection Body weight and length measurement of tagged rainbow trout was conducted before and during the feeding trial. Fish grown in tanks were fed one of four diets in duplicate groups: a basal diet without any supplements (control diet) or a basal diet supplemented with dihydroquercetin (experimental diet 1), arabinogalactan (experimental diet 2) or a mixture of both (experimental diet 3). Description of data collection 124 rainbow trout juveniles (age: 6 months) were included in aquaria experiment. Control group included 32 fish in two tanks (no. 1, n 1 = 16; no. 8, n 2 = 16), experimental group 1 included 30 fish in two tanks (no. 5, n 1 = 14; no. 3, n 2 = 16), experimental group 2 included 32 fish in two tanks (no. 4, n 1 = 16; no. 7, n 2 = 16), experimental group 3 included 34 fish in two tanks (no. 2, n 1 = 17; no. 6, n 2 = 18) ( Fig. 1). Before feeding trial, rainbow trout were PIT tagged to identify individuals. Fish tagging and body weight and length measurement followed by anesthesia using a clove oil bath. Rainbow trout body weight and length measurements were conducted with an accuracy of 0.01 g and 0.01 cm, respectively.

Data source location
Laboratory for Environmental Biochemistry, Institute of Biology of Karelian Research C enter of the Russian Academy of Sciences, Petrozavodsk, Russia. Rainbow trout, O. mykiss , juveniles were obtained from the commercial trout farm, Ladmozero Lake, Republic of Karelia, Russia.

Data accessibility
With the article Value of the Data • The presented data give details on the effect of dietary dihydroquercetin (25 and 10 0 0 mg kg − ¹ of diet), arabinogalactan (50 and 20 0 0 mg kg − ¹ of diet) or their combination (25 + 50 and 10 0 0 + 20 0 0 mg kg − ¹ of diet) on the weight and length of rainbow trout in an aquaria experiment. • These data could be taken into account by fish farmers in the estimation of the effect of natural dietary supplements such as dihydroquercetin and arabinogalactan on rainbow trout growth. These data will be helpful for researchers involved in aquaculture nutrition assessments and related research. • These data support the development of further studies aimed to reveal concentrations of dihydroquercetin and arabinogalactan that may affect the growth performance of farmed rainbow trout. • These data confirm the current knowledge on the growth pattern of rainbow trout juveniles. The dataset presented in this article as a supplementary file (.xls) provides raw data on the growth of rainbow trout individuals fed with dihydroquercetin, arabinogalactan or a mixture of both in an aquaria experiment. It has 7 columns: tag number, measurement date, weight (g), length (cm), group (control, dihydroquercetin-fed, arabinogalactan-fed, or a mixture of dihydroquercetin and arabinogalactan-fed), the concentration of supplements (mg kg − ¹ of feed), and tank number. We applied multilevel linear modeling for repeated measures data, which revealed  no difference in growth parameters (body weight and length) between the control and experimental groups. Data extracted from this experiment are summarized in Fig. 2 . No significant differences in weight ( Fig. 2 A) or length ( Fig. 2 B) between studied groups were found.

Experimental system and fish rearing
All animal handling procedures were approved by the Ethics and Animal Care Committee of the Institute of Biology, Karelian Research C enter of the Russian Academy of Sciences, following EU-established norms and procedures.
On November 1, 2018 rainbow trout, O. mykiss , juveniles (age: 6 months) obtained from a commercial trout farm (Ladmozero Lake, Republic of Karelia, Russia) were transported to the Laboratory for Environmental Biochemistry at the Institute of Biology, Karelian Research C enter of the Russian Academy of Sciences (Petrozavodsk, Russia). Fish were randomly stocked into 8 glass tanks (250 -270 L capacity) with 14-17 fish per tank. Tanks were continuously supplied with aerated water with the flow rate set at 0.16 L min − ¹, water temperature 12 ± 1 °C, dissolved oxygen 7.5-8.5 ppm, total ammonia nitrogen < 0.1 mg L − 1 , nitrite nitrogen < 0.1 mg L − 1 and nitrate nitrogen < 10.0 mg L − 1 , under natural photoperiod. On November 19, 2018 fish were PIT tagged intraperitoneally to identify individuals. Fish were anesthetized using a clove oil bath (25-30 mg L − ¹) before tagging as well as before all subsequent body weight and length measurements. On November 19, 2018 stocking density was 3.24, 3.25, 3.39, 3.24, 3.12, 3.60, 3.29, 3.37 kg m − 3 for tanks from 1 to 8, respectively. Before the start of the feeding trial, all fish were given a basal diet, EFICO Alpha 717R (BioMar, Denmark), containing 22-25% lipid, 40-43% protein, 20-23% carbohydrate, 2.8-5.8% fiber, 0.9% total P, 4-7% ash and 22-25 MJ kg − ¹ total energy. Tagged fish were acclimatized to the experimental conditions for 19 days prior to the start of the feeding trial.

Diet and feeding protocol
Dihydroquercetin, a bioflavonoid, («Lavitol-dihydroquercetin», certificate no. 396-08.17) and arabinogalactan, a polysaccharide, («Lavitol-arabinogalactan», certificate no. 452-08.17) were purchased from Ametis (Russia). Distilled water was used to dissolve supplements; then the solution was heated up to 45 °C and stirred continuously for 1 h. Visual control of the dissolution process made it possible to make sure that there was no sediment. The solution with supplements was sprayed onto feed pellets from a spray gun directly on the day of feeding. Then the feed pellets were dried at room temperature for an hour. In the control group, distilled water alone was added to the feed.
The feeding trial was started on December 8, 2018. Fish were fed one of four diets in duplicate tanks: a basal diet without any supplements (control diet) or a basal diet supplemented with dihydroquercetin (25 mg kg − ¹ of diet; experimental group 1), arabinogalactan (50 mg kg − ¹ of diet; experimental group 2) or a mixture (25 + 50 mg kg − ¹ of diet, respectively; experimental group 3). The supplement concentrations listed above were recommended by the manufacturer (Ametis, Russia) for fish farming. Fish were fed these diets until March 20, 2019. From March 21, 2019 until May 15, 2019, fish were fed diets with a 40-fold increase of the initial supplement concentration: a basal diet without any supplements (control diet), or a basal diet supplemented with dihydroquercetin (10 0 0 mg kg − ¹ of diet; experimental group 1), arabinogalactan (20 0 0 mg kg − ¹ of diet; experimental group 2) or a mixture of both (10 0 0 + 20 0 0 mg kg − ¹ of diet, respectively; experimental group 3). High concentrations of dihydroquercetin (10 0 0, 50 0 0 and 10,0 0 0 mg kg − ¹ of diet) have been used previously in the experiment with gilthead seabream with no toxicity for fish [1] . Fish were fed once a day; the feeding level based on percent of tank biomass was equal for experimental and control groups. The food was eaten completely. Pellet size of the diet was equal for all groups. From November 1, 2018 until March 1, 2019 pellet size of the diet was 3 mm, and from March 1, 2019 it was 4 mm.

Experimental data analysis
The analysis of repeated measures data was performed utilizing a multilevel linear model (MLM). The data were analyzed with the lmer function from the lme4 package [2] for R [3] . The differences between the experimental groups were evaluated using F-and t-tests for the objects returned by a mixed model function with a p value cutoff of 0.05 for statistical significance.

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article.