M. García-Gallego

Evaluation of lupin seed meal as an alternative protein source in feeding of rainbow trout (Salmo gairdneri)

Abstract The nutritive quality of trout diets including lupin seed meal at 10, 20, 30 and 40% of dietary protein content was evaluated. Influence of heating on nutritional quality was also tested. Food intake, conversion index, digestibility of dietary protein, protein efficiency ratio and protein productive value were the parameters evaluated. The possibility of including crude lupin seed meal in trout diets at levels as high as 30% of dietary protein was demonstrated. Heating did not improve nutritional quality.

Effect of starvation and refeeding on digestive enzyme activities in sturgeon (Acipenser naccarii) and trout (Oncorhynchus mykiss)

The digestive enzyme activities were determined in Adriatic sturgeon and rainbow trout during starvation and refeeding period. Overall, the digestive enzyme activities are affected in the same sense in both species. The protease and lipase activities were decreased later than amylase activity. Even after 1 month of starvation, both species would be prepared to digest protein and lipids in an effective way. After 72 days of starvation, the digestive machinery of the sturgeon and of the trout shows an altered capacity to digest macronutrients. The capacity to digest proteins and lipids, after 60 days of refeeding, begins to become re-established in sturgeon and trout. In contrast, in this period, the capacity to digest carbohydrates remains depressed in both species.

Biology, Conservation and Sustainable Development of Sturgeons

Taxonomy and Biogeography.- The Regression of Sturgeons in Southern Europe.- Analysis of Mitochondrial and Nuclear DNA Markers in Old Museum Sturgeons Yield Insights About the Species Existing in Western Europe: A. sturio, A. naccarii and A. oxyrinchus.- Morphological and Morphometric Characters in Sturgeon Taxonomy and Phylogeny.- Molecular Markers and the Study of Phylogeny and Genetic Diversity in North American Sturgeons and Paddlefish.- Forensic Strategies Used for DNA Extraction of Ancient and Degraded Museum Sturgeon Specimens.- Mechanisms of Polyploid Evolution in Fish: Polyploidy in Sturgeons.- Biology and Aquaculture.- Histological, Histochemical and Ultrastructural Changes in the Digestive Tract of Sturgeon Acipenser naccarii During Early Ontogeny.- The Developmental Anatomy of the Heart of the Sturgeon Acipenser naccarii.- Observations on the Brain Development of the Sturgeon Acipenser naccarii.- Hormonal Induction of Ovulation In Vitro in Sturgeon Fishes.- Dispermic Androgenesis as a Method for Recovery of Endangered Sturgeon Species.- Influence of Temperature on the Sterlet (Acipenser ruthenus L.) Ovarian Follicles State.- On Nutrition and Feeding Studies as the Basis for the Culture of Different Sturgeon Species.- Recovery and Conservation.- Restoration of Adriatic Sturgeon (Acipenser naccarii) in Italy: Situation and Perspectives.- Acipenser sturio Recovery Research Actions in France.- Conservation of the Sturgeon Fish in Lower Volga.- Experience of Conservation of Acipenser naccarii in the Ticino River Park (Northern Italy).- Identification of Sturgeon Caviar Using DNA Markers.- International Trade in Caviar and Business Perspectives in Russia.- The Ecological Problems of Introduction and Reintroduction of Sturgeons.- Hydrological and Production Characteristics of the Main Basins for Reproduction and Fattening of Sturgeons.- Towards the Definition of Optimal Size-Weight Standards of Hatchery-Reared Sturgeon Fry for Restoration.- Acceptability and Prerequisites for the Successful Introduction of Sturgeon Species.- Prerequisites for the Restoration of the European Atlantic Sturgeon, Acipenser sturio and the Baltic Sturgeon (A. oxyrinchus x A. sturio) in Germany.- Sturgeon Recovery Plan in the Rhone River (France): Preliminary Results on Species Determination and Habitat Suitability.- Main Steps and Proposals for a Recovery Plan of Sturgeon in the Guadalquivir River (Spain).

Liver and white muscle protein turnover rates in the / European eel Anguilla anguilla: effects of dietary protein quality

Abstract The influence of the quality of dietary protein source on growth and protein synthesis and degradation rates was studied in the liver and white muscle of the European eel. Fish were fed isonitrogenous diets differing in protein source: one (control) contained fish meal, three others incorporating meat meal (MM) or sunflower meal (SFM) as the only protein source, and SFM supplemented with some essential amino acids (EAAs) were also tested. Fish fed diets containing unsupplemented MM or SFM exhibited dietary utilization and growth indices poorer than those fed the control, while EAA supplementation greatly improved the performance of the SFM-diet. Liver showed higher rates of protein synthesis ( k s ) and degradation ( k d ) associated with a higher capacity for protein synthesis per unit of DNA but a lower protein deposition efficiency (PDE), compared to muscle. Low quality dietary protein increased the protein turnover rate, with a higher protein synthesis rate per unit of DNA and RNA but a decrease of PDE. In white muscle, MM and unsupplemented SFM diets decreased k s without changing k d . The MM diet reduced the efficiency of protein synthesis and deposition. EAA supplementation of the SFM diet raised the protein synthesis rate and capacity as well as protein deposition compared to control values.

Use of protein sources alternative to fish meal in diets with amino acids supplementation for the European eel ( Anguilla anguilla )

This experiment was conducted to test two different protein sources as alternatives to the commonly used fish meal (FM) in the diet of the European eel (Anguilla anguilla). Six experimental diets were tested in three replicated lots of European eels. All diets contained the same protein and energy content (ca, 300 g crude protein per kg dry matter and 18·5 MJ/kg, respectively) but differed in the nature of the protein source: FM was the only protein source in the control diet and was fully or partially (0–5: 0–5) replaced by meat meal (MM) or sunflower meal (SFM) in four other diets; a sixth diet included SFM as the only protein source but was supplemented with several essential amino acids. Food intake, fish growth and several indices of diet and protein utilization were measured. MM clearly was the poorest protein source while SFM could replace, at least 0·5 of the FM with no significant reduction in performance. In addition, the European eel was able to utilize the supplement of essential amino acids. The full-SFM diet was improved significantly when supplemented and results were not statistically different from the control FM-based diet. Overall, a good correlation was found between the results of each diet and the respective essential amino acid index, calculated using as reference the essential amino acid requirements previously defined for another eel species, Anguilla japonica. This index could be used as a reliable measure for an a priori evaluation of alternative protein sources to be included in commercial foods for eels.

Utilization of dietary carbohydrates by fish: a comparative study in eel and trout

To evaluate the ability of the eel to use diets with high carbohydrate content, a comparative study was made by using the rainbow trout, a carnivorous fish, as a reference species. Four isoenergenetic diets (in terms of gross energy) were formulated incorporating different protein/carbohydrate ratios (450/200, 370/300, 290/400 and 210/500 as g/kg dry matter, respectively) and each one was tested in three replicates groups of eels and trout. The data on growth, food conversion and utilization of dietary protein and energy show that the eel has a comparatively greater ability than the rainbow trout for using diets with a high carbohydrate level. Thus it is postulated that higher carbohydrate levels could be used for formulating cheaper diets.

On Nutrition and Feeding Studies as the Basis for the Culture of Different Sturgeon Species

Any attempt to save the endangered sturgeon species will depend on the availability of a sufficient stock of the fish in question, as aquaculture is a very suitable tool and has proved feasible for several sturgeon species and, additionally, it could contribute to the development of a new productive activity.

Influence of pre-slaughtering feed restriction on muscle characteristics of farmed sea bass (Dicentrarchus labrax L.) during cold storage

BACKGROUND This paper deals with the consequences of dietary restriction or complete starvation before slaughtering on the biochemical and textural characteristics of sea bass muscle. RESULTS Results showed that only severe feed restriction influenced negatively total body and individual organ weights, and these animals showed lower condition factor as well. Neither moderate feed restriction (up to 50% of the standard ration) kept for 30 days nor total starvation up to 12 days caused significant effects on fish weight and fillet yield. Muscle lipid content was lower in feed-restricted fish, although this parameter was not altered by starvation time. Differences between the two feeding strategies studied were observed in muscle textural and biochemical parameters, and the results point to an influence of the nutritional status on the post-mortem evolution of collagen and myofibrillar proteins, although firmness was not modified. CONCLUSIONS Moderate feed restriction prior to slaughtering could be advisable in sea bass culture, given that no detrimental effects on fish quality or fish performance were noticed, whereas substantial amounts of feed can be saved.

Histological, Histochemical and Ultrastructural Changes in the Digestive Tract of Sturgeon Acipenser naccarii During Early Ontogeny

Besides species diversification, current priorities in aquiculture include the development of suitable inert diets to enable the artificial feeding of fish from the onset of exogenous feeding. Achieving this aim demands knowledge of the structural and functional characteristics of the digestive tract throughout ontogeny. This chapter provides a histological, histochemical and ultrastructural analysis of the digestive tract of Acipenser naccarii sturgeons during different ontogenic development stages (lecithotrophic, lecithoexotrophic and exotrophic periods). These data are essential to our understanding of the digestive capacity of this species during the first stages of life. The knowledge gained will be useful for the investigation and design of appropriate diets to optimize the farming of this species, an activity of major ecological and economic importance.

Use of freeze-dried microalgae for rearing gilthead seabream, Sparus aurata L., larvae. II. Biochemical composition

The objectives of this study were to test whether freeze-dried microalgae are nutritionally adequate for rearing rotifers as food for gilthead seabream larvae. The elemental composition (C, N, H) and fatty acid composition were analysed in larvae of gilthead seabream, Sparus aurata L., rotifers Brachionus plicatilis and Brachionus rotundiformis and freeze-dried microalgae Nannochloropsis oculata. Four larval feeding treatments were tested: (A) larvae fed rotifers cultivated with freeze-dried microalgae and daily addition of freeze-dried microalgae to the larval tanks; (B) larvae fed rotifers cultivated with freeze-dried microalgae and daily addition of live microalgae to the larval tanks; (C) larvae fed rotifers cultivated with freeze-dried microalgae, without addition of microalgae to the larval tank and (D) larvae fed rotifers cultivated with live microalgae and daily addition of live microalgae to the larval tanks. No significant differences were observed between the biochemical composition of larvae with treatment A (with freeze-dried microalgae) and the composition of larvae in treatment D that were obtained with the acceptable methods for culture systems (with live microalgae).