Effects of Stocking Density on Growth Performance and Stress Responses of Bester and Bester ♀ × Beluga ♂ Juveniles in 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 s...

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Bibliographic Details
Published in:Animals
Main Authors: Lorena Dediu, Angelica Docan, Mirela Crețu, Iulia Grecu, Alina Mogodan, Marilena Maereanu, Lucian Oprea
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2021
Subjects:
stocking density
hybrid sturgeons
overcrowding stress
physiological response
RAS
serum parameters
Veterinary medicine
SF600-1100
Zoology
QL1-991
Beluga
Beluga*
Online Access:https://doi.org/10.3390/ani11082292
https://doaj.org/article/041a3ec05ddb4481a958731223a17b02
Description
Summary: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/m 2 and 4 kg/m 2 in fiberglass tanks (1 m 3 ) 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/m 2 to 12 kg/m 2 . 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.

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