scholarly journals Effects of Stocking Density on Growth Performance and Stress Responses of Bester and Bester ♀ × Beluga ♂ Juveniles in Recirculating Aquaculture Systems

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2292
Author(s):  
Lorena Dediu ◽  
Angelica Docan ◽  
Mirela Crețu ◽  
Iulia Grecu ◽  
Alina Mogodan ◽  
...  
Keyword(s):  
Growth Performance ◽  
Stress Responses ◽  
Stocking Density ◽  
Serum Cortisol ◽  
Lower Serum ◽  
Serum Parameters ◽  
Hematological Indices ◽  
Recirculating Aquaculture ◽  
Crowding Stress ◽  
Recirculating Aquaculture Systems

The study aimed to compare the growth performance and physiological responses of bester (B) and backcrossed bester ♀ × beluga ♂ (BB) in response to crowding stress under different stocking densities, as well as to establish a threshold stocking density for rearing BB in a recirculating aquaculture system (RAS) without welfare impairment. For this purpose, in the first trial (T1), B (181.15 ± 21.21 g) and BB fingerlings (181.98 ± 28.65 g) were reared in two stocking densities of 2 kg/m2 and 4 kg/m2 in fiberglass tanks (1 m3) for 6 weeks. In a parallel trial (T2), the BB hybrids (335.24 ± 39.30 g) were kept in four initial stocking densities, ranging from 5 kg/m2 to 12 kg/m2. The results of T1 revealed better growth indices (i.e., final mean weight, weight gain, specific growth rate) at lower stocking densities for both hybrids; however, in terms of growth performance, the BB hybrid showed better results when compared with the B hybrid. BB hybrids registered significantly (p < 0.05) lower serum cortisol and MDA and higher lysozyme than B hybrids, showing higher tolerance to crowding stress. Nevertheless, at higher densities, selected serum parameters (i.e., hematological indices, cortisol, glucose, protein, malondialdehyde, lysozyme) and growth performance indices used to evaluate the hybrids indicate that high stocking density could affect the growth and welfare of BB hybrids, and that the selected serum parameters could be used as good indicators for chronic stress caused by overcrowding conditions.

scholarly journals SUBSTANTIATING SCALES OF SIMILARITY OF OPTICAL QUANTITIES IN HYDROBIONT GROWING SYSTEMS

2021 ◽  
Vol 2021 (1) ◽  
pp. 7-13
Author(s):  
Alexander Alekseevich Nedostup ◽  
Alexey Olegovich Razhev ◽  
Evgeniy Ivanovich Khrustalyov ◽  
Kseniia Andreevna Molchanova
Keyword(s):  
Computer Vision ◽  
Optimal Algorithm ◽  
Stocking Density ◽  
Aquatic Organisms ◽  
Similarity Criteria ◽  
Light Effect ◽  
Behavioral Reactions ◽  
Recirculating Aquaculture ◽  
Recirculating Aquaculture Systems ◽  
Growing Conditions

The article highlights the problems of physical modeling the elements of recirculating aquaculture systems (RAS) and open aquaculture cages (OAC) for hydrobionts growing, in particular, the question of substantiating the rules of optical quantities similarity has been raised. Formulation of the problem is based on the assumption that using the computer vision which controls the behavioral reactions of hydrobionts to the growing conditions (e.g. light effect) will make the biotechnological process controllable in RAS and OAC and, as a result, more efficient. Evaluating the light effect on biological objects as to the depth of its penetration into the basins, the degree of its dispersion among the aquatic organisms and other characteristics can become an important element of computer vision. This fact will help to choose the optimal algorithm for the biotechnical process, for example, to calculate the daily feed portion and feeding periods, to define the optimal place for feeding, to determine the appropriate sorting time, the optimal stocking density, etc. There have been proposed the additional similarity scales for optical quantities, methods for their calculation and graphs of their dependences on the geometric scale Cl. However, one should know that achieving the complete similarity is absolutely impossible, no matter how large the list of similarity criteria is.

scholarly journals Determination of stocking density limits for Crassostrea gigas larvae reared in flow-through and recirculating aquaculture systems and interaction between larval density and biofilm formation

2017 ◽  
Vol 30 ◽  
pp. 29 ◽  
Author(s):  
Katia Asmani ◽  
Bruno Petton ◽  
Jacqueline Le Grand ◽  
Jérôme Mounier ◽  
René Robert ◽  
...  
Keyword(s):  
Crassostrea Gigas ◽  
Biofilm Formation ◽  
Larval Density ◽  
Stocking Density ◽  
Rrna Gene ◽  
Larval Rearing ◽  
Filamentous Bacteria ◽  
Recirculating Aquaculture ◽  
Recirculating Aquaculture Systems ◽  
Flow Through

The first aim of this study was to determine the stocking density limits for Pacific oyster Crassostrea gigas larvae reared in flow-through system (FTS) and recirculating aquaculture systems (RAS). The second aim was to examine biofilm formation on the larval tank wall and its interaction with larvae growth. Three larvae concentrations were tested: 50, 150, and 300 mL−1. Chemical parameters and larvae performance were measured. The biofilm was observed by scanning electron microscopy, and its bacterial composition was investigated by pyrosequencing analysis of part of the 16S rRNA gene. The highest growth (13 µm day–1), survival (87%) and metamorphosis (50%) rates were observed in FTS at 50 larvae mL–1, while lower and similar performances occurred at 150 larvae mL–1 in both systems. At 300 larvae mL−1, performances dropped with occurrence of mortality. Biofilm thickness increased with larval density. The pioneer bacteria were coccobacilli followed by filamentous bacteria. The latter constituted abundant braids at the end of rearing at high larval concentrations. The first colonizers were mainly Rhodobacteraceae (α-Proteobacteria). The filamentous bacteria were Saprospirae (Bacteroidetes) and Anaerolineae (Chloroflexi). The biofilm was also made up of other minor groups, including Actinobacteria, Planctomycetes, δ-, γ-Proteobacteria, and Flavobacteriales. The biofilm's composition was more similar to that found in a sewage reactor than in open-sea collectors, which might negatively influence larval rearing due to potential metabolites. This first study on biofilms provides insights into the interaction between rearing density and larvae performance.

Effects of dietary tryptophan supplementation and stocking density on growth performance and stress responses in rainbow trout (Oncorhynchus mykiss)

Aquaculture ◽  
2020 ◽  
Vol 519 ◽  
pp. 734908 ◽  
Author(s):  
Seyyed Morteza Hoseini ◽  
Ali Taheri Mirghaed ◽  
Melika Ghelichpour ◽  
Esmaeil Pagheh ◽  
Yousef Iri ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Growth Performance ◽  
Stress Responses ◽  
Stocking Density ◽  
Rainbow Trout Oncorhynchus Mykiss
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