ADVANCES IN THE EARLY LARVAL STAGES OF SIBERIAN STURGEON: MUSCLE DEVELOPMENT AND STRUCTURE UNDER DIFFERENT REARING CONDITIONS
Tesi di Dottorato
Data di Pubblicazione:
2019
Citazione:
ADVANCES IN THE EARLY LARVAL STAGES OF SIBERIAN STURGEON: MUSCLE DEVELOPMENT AND STRUCTURE UNDER DIFFERENT REARING CONDITIONS / M.l. Matela Da Silva Aidos ; tutor: A. Di Giancamillo ; coordinator: F. Gandolfi. DIPARTIMENTO DI SCIENZE VETERINARIE PER LA SALUTE, LA PRODUZIONE ANIMALE E LA SICUREZZA ALIMENTARE, 2019 Feb 28. 31. ciclo, Anno Accademico 2018. [10.13130/matela-da-silva-aidos-maria-lucia_phd2019-02-28].
Abstract:
Fish larval stages are particularly sensitive to environmental conditions, as these can severely affect survival and potential growth. In fish species destined for production and commercialisation, a suitable early environment is of great importance, for what concerns growth efficiency and quality at harvest. Temperature and stocking density are among the most important factors affecting the early stages of development, regarding somatic and muscle growth of fish. Moreover, environmental enrichment is considered to improve biological functioning of captive animals, including fish, by improving their psychological and behavioral needs.
Siberian sturgeon (Acipenser baerii) is a species at risk of extinction and, therefore, production of this species in aquaculture is of vital importance, not only to provide the market with caviar and meat, but also for repopulation purposes. Taking into account that little is known regarding the impact of environmental conditions in early life stages of the Siberian sturgeon, the aim of this Thesis is to provide new knowledge on the influence on muscle growth and development during the endogenous feeding phase. This was performed by addressing morphological, physiological and molecular aspects of muscle growth structure and development. This Thesis may contribute to identify and select the most suitable environmental conditions to improve Siberian sturgeon larval rearing in aquaculture production.
Three trials have been performed, one in each year of my PhD, where 1) rearing temperature, 2) stocking density and 3) environmental enrichment were examined in important timepoints of Siberian sturgeon larvae development: hatching, schooling and complete yolk-sac absorption stage.
In Chapter 1, is presented a general overview of Siberian sturgeon biology and development, a brief description of the muscle morphology and of the methods used to study muscle growth. Following, the types of sturgeon muscle growth are described, as well as the mechanisms involved in muscle growth regulation. Finally, the environmental effects on growth are presented along with a short overview of the plasticity of the myogenic phenotype.
In Chapters 2, 3 and 4, the effects of three different rearing temperatures (16, 19 or 21 °C) applied from hatching until the yolk-sac full absorption were assessed. Siberian sturgeon fertilized eggs were all incubated at 16°C and newly-hatched larvae were then subjected to three different temperatures throughout the endogenous feeding phase. All the three experimental rearing temperatures were congruent with a correct development of farmed A. baerii (Chapter 2, 3 and 4), but a rearing temperature of 22°C lead to a higher developmental rate, which could be advantageous in commercial hatcheries, as it shortens the endogenous feeding phase and allows to feed the larvae sooner with exogenous feed. In Chapter 2, histometrical, histochemical and immunohistochemical analyses were performed in order to characterize muscle growth (total muscle area, TMA; slow muscle area, SMA; fast muscle area, FMA), development (anti proliferating cell nuclear antigen –PCNA) as well as stress status by specific stress biomarkers (heat shock protein 70 or 90; HSP70 or HSP90). Histometry revealed that both TMA and FMA were larger in the schooling stage at 19°C while no differences were observed in the SMA at any of the tested rearing temperatures. PCNA quantification revealed a significantly higher number of proliferating cells in the yolk-sac absorption phase at 22°C than at 16°C. HSP90 immunopositivity seems to be particularly evident at 19°C. HPS70-immunopositivity was never observed in the developing lateral muscle. It was possible to conclude from this study that a temperature of 19°C could be taken i
Tipologia IRIS:
Tesi di dottorato
Elenco autori:
M.L. MATELA DA SILVA AIDOS
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