The present study was conducted in the frame of the project DIVERSIFY to investigate the effects of different feeding frequencies in larger greater amberjack juveniles (> 250 g). During the trial, fish growth performance and feed efficiency were evaluated.Postprin

Jerez, S. (Salvador)

English

The present study was conducted in the frame of the project DIVERSIFY to investigate the effects of different feeding frequencies in larger greater amberjack juveniles (> 250 g). During the trial, fish growth performance and feed efficiency were evaluated.N

Jerez, Salvador

Digital.CSIC

Evaluation of different feeding frequencies in the growth of greater amberjack juveniles

The present study was conducted in the frame of the project DIVERSIFY to investigate the effects of different feeding frequencies in larger greater amberjack juveniles (> 250 g). During the trial, fish growth performance and feed efficiency were evaluated

Repositorio Institucional Digital del IEO

32 Greater amberjack (Seriola dumerili) has recently attracted much attention and has been recognized as one of the more promising candidates to help diversify finfish aquaculture produc-tion. It is expected to increase in future production based on the successful progress achieved in recent years and due to the relevant results obtained in the recently concluded DIVERSIFY project. The use of appropriate feed manage-ment strategies results in higher growth rates, improved feed efficiency and less feed wasted with the consequent economic and environmental advantages. There are a few previous studies on frequency and ration effects on greater amberjack growth performance (De la Gandara et al., 2004; Jerez, 2013), but the information is scarce. The results obtained during the project DIVERSIFY related to parameters that affect the Evaluation of different feeding                  frequencies in the growth of greater amberjack juveniles By Salvador Jerez Herrera, Centro Oceanográfico de Canarias, Instituto Español de Oceanografía, Tenerife,                                          Islas Canarias, Spain. Feeding the right way is fundamental to improve the growth performance and condition of reared greater amberjack, reduce the feed cost and prevent environmental deterioration.  FEED MANAGEMENT  33 use of feed on the farm (temperature, feeding rates, stocking densities) are of great importance for the industrial production of this species (Mylonas et al., 2019). The present study was conducted in the frame of the project DIVERSIFY to investigate the effects of different feeding frequencies in larger greater amberjack juveniles (> 250 g). During the trial, fish growth performance and feed efficiency were evaluated.  Growth trial One hundred and eighty greater amberjack juveniles (~250 g and 23.0 cm, initial body weight and length, respectively) produced in the facilities of the Centro Oceanográfico de Canarias (Instituto Español de Oceanografía) in Tenerife, Spain, were divided into 12 homogeneous groups and reared with a constant water exchange and aeration and under natural photoperiod, salinity and temperature during four months. Triplicate fish groups were fed daily ad libitum with a commercial turbot diet (3-5 mm diameter; Skretting Ltd, Norway; 52 % crude protein and 20% crude fat) at a feeding frequency of 1 (08:00 h), 2 (08:00 and 18:30 h), 3 (08:00, 13:30 and 18:30 h) and 7 (08:00, 10:00, 12:00, 13:30, 15:00, 17:00 and 18:30 h) meals day-1. The daily feed intake was calculated (FI). Fish were sampled and weight gain (WG, g), percentage of weight gain (% WG, %), coefficient of variation for weight (CV, %, standard deviation by mean weight), feed conversion ratio (FCR, feed consumed by biomass produced) and condition factor (K, g cm-3, body weight by cubic length) were estimated. Five fish at the beginning and six fish per treatment at the end of the trial (120 days) were slaughtered and hepatosomatic (HSI, %) and viscerosomatic index (VSI, %) were used as production performance indices.   Fig. 1. Facilities of IEO in Tenerife, Canary Islands (COC).  Fig. 2. Greater amberjack hand-fed.  34 Results During the experiment, average DO was 92.4 ± 4.8 % (7.1 ± 0.4 mg O2 l-1), and temperature decreased from 19.4 ºC to 18.1 ºC throughout the experiment (mean ± S.D. temperature of 18.8 ± 0.4 ºC). In this study, greater amberjack juveniles fed 1 meal day-1 showed a lower final body weight (by 392 g) than the other three feeding strategies (2, 3 and 7 meals day-1). However, the different feeding frequencies did not affect body weight variations of fish (P > 0.05), although fish fed 1 and 7 meals day-1 showed the higher coefficient of variation (CV) (Table 1). The WG of fish fed 1 meal day-1 was lower (by 117 g) than the one shown by fish fed 2, 3 and 7 meals day-1, which presented a percentage of weight gain of 53.3, 57.6 and 60.7 %, respectively, values between 10 and 17% higher than showed by fish fed 1 meal day-1 (by 43 %) (Table 1). Fish fed 1 meal day-1 showed a significantly lower condition factor (K) compared to 7 meals day-1 (P < 0.05) at the end (120 days). Also, hepatoso-matic index (HSI) was lower in 1 meal day-1 respect to 3 meals day-1 (P < 0.05) (Table 2). Furthermore, fish fed 1 meal day-1 showed a marked decrease of K (13.7 %) and HSI (61.2 %) respect to the initial indices (2.12 ± 0.09 and 1.27 ± 0.14, for K and HSI, respectively). However, viscerosomatic index (VSI) was similar regardless of the feeding strategy and decreasing between 46.8 and 43.2 % respect to the initial value Fig. 4. Feed intake (FI) and feed conversion rate (FCR) of greater amberjack juveniles fed 1, 2, 3 and 7 meals day-1 after 120 days. The data presented are means of the three                           replicates. Different letters indicate significant differences (P < 0.05). Table 1. Initial and final body weight (g), and coefficient of variation (CV, %) of body weight of greater amberjack juveniles fed at 1, 2, 3 and 7 meals day-1 after 120 days. The data presented are mean ± S.D. of the 3 replicates. Treatment Initial Body Weight (g) Final Body Weight (g) CV (%) 1 meal day-1 266.3 ± 9.4 392.2 ± 32.6 19.6 ± 6.0 2 meal day-1 260.6 ± 7.1 399.6 ± 15.8 17.5 ± 2.7 3 meal day-1 256.0 ± 14.6 404.9 ± 11.6 17.5 ± 3.0 7 meal day-1 260.7 ± 14.4 409.7 ± 30.8 18.8 ± 8.9 Table 2. Condition factor index (K; g cm-3), hepatosomatic (HSI; %) and viscerosomatic  index (VSI; %) and percentage of decrease with respect to the initial value of greater              amberjack juveniles fed 1, 2, 3 and 7 meals day-1 after 120 days. The data presented are means of the three replicates. Different letters indicate significant differences (P < 0.05). Treatment K Change vs. initial HSI Change vs. initial VSI Change vs. initial   (g cm-3) (%) (%) (%) (%) (%) 1 meal day-1 1.83 b 13.7 0.49 b 61.2 3.19 45.7 2 meal day-1 1.89 ab 11.3 0.68 ab 46.6 3.35 43.2 3 meal day-1 1.83 ab 12.4 0.73 a 42.7 3.20 45.6 7 meal day-1 1.91 a 11.2 0.69 ab 45.1 3.14 46.8 35 (5.89 ± 0.79). Fish fed 1 meal day-1 showed the higher feed intake (FI), about 37% more feed compared to fish fed 7 meals day-1 (Fig. 2). Furthermore, they showed the worst food efficiency, resulting in reduced FCR (by 2.5 %). For larger greater amberjack juveniles (> 250 g), the better results in growth performance and feed conversion rates were obtained when fish were fed from 2 to 7 meals day-1. The findings of the current study have practical significance for establishing greater amberjack rearing practice. Furthermore, a technical “production manual” for greater amberjack has been also released by the project and is freely available in the project’s website. It can be used by the industry to continue the study of the potential of greater amberjack as an alternative marine species for European warm-water aquaculture.  References available on request.  Acknowledgments The project DIVERSIFY was funded by the European Union’s Seventh Framework Program for research, technological development and demonstration (KBBE-2013-07 single stage, GA 603121, DIVERSIFY). Exploring the biological and socio-economic potential of new/emerging candidate fish species for expansion of the European aquaculture industry, six new/emerging finfish species were identified with a great potential for the expansion of EU aquaculture. This EU funded project, which started in 2013, achieved all its objectives in the greater amberjack research. The knowledge achieved let greater amberjack to be considered as a feasible farmed species for the aquaculture industry.     AFΩ Salvador Jerez Herrera Senior Researcher IEO, Centro Oceanográfico de Canarias, Spain E: salvador.jerez@ieo.es https://www.diversifyfish.eu.  

Greater amberjack (Seriola dumerili)
has recently attracted much attention
and has been recognized as one of the
more promising candidates to help
diversify finfish aquaculture production. It is expected to increase in
future production based on the
successful progress achieved in recent
years and due to the relevant results
obtained in the recently concluded
DIVERSIFY project.
The use of appropriate feed management strategies results in higher
growth rates, improved feed
efficiency and less feed wasted with
the consequent economic and
environmental advantages. There are
a few previous studies on frequency
and ration effects on greater
amberjack growth performance (De la
Gandara et al., 2004; Jerez, 2013), but
the information is scarce. The results
obtained during the project DIVERSIFY
related to parameters that affect the
use of feed on the farm (temperature,
feeding rates, stocking densities) are
of great importance for the industrial
production of this species (Mylonas et
al., 2019).
The present study was conducted in
the frame of the project DIVERSIFY to
investigate the effects of different
feeding frequencies in larger greater
amberjack juveniles (> 250 g). During
the trial, fish growth performance and
feed efficiency were evaluated

http://www.repositorio.ieo.es/e-ieo/bitstream/10508/12284/1/32%20%20Evaluation%20of%20different%20feeding%20frequencies%20in%20the%20growth%20of%20greater%20amberjack%20juveniles.pdf

Evaluation of different feeding frequencies in the growth of greater amberjack juveniles

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