Fabio Caprino

Effects of alternative dietary lipid sources on performance, tissue chemical composition, mitochondrial fatty acid oxidation capabilities and sensory characteristics in brown trout (Salmo trutta L.)

The efficiency of five dietary lipid sources (fish oil as control—C; canola oil—CO; poultry fat—PF; pork lard—PL; and oleine oil—OO) were evaluated in juvenile brown trout (58.4±0.7 g) in an experiment conducted over 70 days at 14.6±0.4 °C. The best growth was observed in fish fed the C diet whereas the PL diet fed fish had the best feed utilization. Significant differences in carcass and muscle proximate composition, but not in liver, were noted among fish fed the different dietary treatments. The fatty acid composition of muscle largely reflected that of the diets, while total cholesterol was not affected. The atherogenicity and the thrombogenicity qualities of the trout flesh were modified by the lipid sources. Sensory analysis did not show any significant differences among the cooked fillets with respect to dietary treatments, while in uncooked products, some significant differences were observed. The carnitine palmitoyltransferase I and II (CPT-I and CPT-II) activities of liver and white muscle were assayed for a better understanding of the potential β-oxidation capability of the different dietary lipid sources. The hepatic, but not white muscle CPT-I and CPT-II activities were affected by dietary treatments. This study showed that alternative lipid sources could be used effectively for oil coating extruded diets for brown trout.

Traceability issues in fishery and aquaculture products

Nowadays availability and international trade of fish and seafood are strongly influenced by food safety norms. Several European Directives have introduced safety standards into the chain for fisheries and aquaculture products with the concept ‘from farm to fork’, usually based on the Codex Alimentarius provisions. A labelling regulation for fishery and aquaculture products came into effect in the European Union in 2001, requiring identification of the official commercial and scientific name, the origin of the fish and its production method (farmed or wild). This regulation aims to provide consumers with a minimum of information on characteristics of such products and is enforced in Italy by Ministry of Agriculture Decree No. 27.03.02 on the labelling of fish products. In addition, in Regulation No. 178/2002, which lays down procedures in the matter of food safety and establishment of the European Food Safety Authority, the Commission defines traceability as ‘the ability to trace and follow a food, feed, foodproducing animal or substance intended to be or expected to be incorporated into a food or feed, through all stages of production, processing and distribution’. As a consequence of these regulations, various labelling schemes from producers and distributors are now in place for fish products. These aim to promote resource sustainability, distinction of quality and product safety. Typically, such producer’s or distributor’s labels inform the consumer as to which aquaculture techniques have been used and which type of feed or raw materials have been used in the feed formulation. New interest in organic fish products or ‘natural’ fish products is also particularly intense in aquaculture, although current schemes tend to be complex and expensive and, so far, a ‘physiological’ incompatibility between aquaculture and organic production of fish seems to exist. Consumers are increasingly interested in ‘natural’ or wild fish products. This results from a decreased confidence in the quality and safety of farmed fish, especially that produced in other countries, as well as concern about environmentally friendly production methods. Unfortunately, recent food scares (i.e. BSE) and the malpractices of some food

The Health Benefit of Seafood

Due to the continuous demand on the part of consumers for high-quality healthy food, primary animal production systems are trying to reduce the impact of some risk factors on human health. The available technologies for farmers to reach this goal seem to lie in genetic improvement and the improvement of feeding and management practices. To date many nutritional theories have focused their attention on the numerous health implications of the fatty acid profile of the diet; in particular the relationship between saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), long-chain polyunsaturated fatty acids (PUFA) of both the n-3 and n-6 categories, seems to play a major role. An important feature of polyunsaturated fatty acids, in particular n-3 fatty acids, is their role in the prevention and modulation of certain diseases that are common in industrialized countries. These are the following (Pike, 1999): (i) impaired development of brain and visual acuity (reduced intellectual capacity in infants, aggression and depression); (ii) neurological dysfunction, including visual symptoms; (iii) inflammatory and autoimmune disorders (rheumatoid arthritis, psoriasis, ulcerative colitis, asthma); (iv) coronary heart disease (restenosis, cardiac arrhythmias); (v) mild hypertension (high blood pressure). As shown in numerous studies, coronary heart diseases (CHD) are largely influenced by dietary habits in correlation with the characteristic lipid profile. Pike (1999) reported interesting data about the characterization of the lipids in the human diet in relationship to the incidence of cardiac and coronary pathologies. He observed that in the last two centuries, with the continuous increase in the consumption of total lipids and SFA and the parallel diminution of the assumption of PUFA and n-3 fatty acids, a remarkable increase of the percentage incidence of cardiovascular pathologies has been recorded. It is known that CHD are caused by obstruction of the coronary vessels by the formation of atheromi or thrombi and, as suggested by Ulbricht and Southgate (1991), it seems that CHD can be influenced by seven dietary factors that

Fatty acid composition and volatile compounds of caviar from farmed white sturgeon (Acipenser transmontanus)

The present study was conducted to characterize caviar obtained from farmed white sturgeons (Acipenser transmontanus) subjected to different dietary treatments. Twenty caviar samples from fish fed two experimental diets containing different dietary lipid sources have been analysed for chemical composition, fatty acids and flavour volatile compounds. Fatty acid make up of caviar was only minimally influenced by dietary fatty acid composition. Irrespective of dietary treatments, palmitic acid (16:0) and oleic acid (OA, 18:1 n-9) were the most abundant fatty acid followed by docosahexaenoic acid (DHA, 22:6 n-3) and eicopentaenoic (EPA, 20:5 n-3). Thirty-three volatile compounds were isolated using simultaneous distillation-extraction (SDE) and identified by GC-MS. The largest group of volatiles were represented by aldehydes with 20 compounds, representing the 60% of the total volatiles. n-Alkanals, 2-alkenals and 2,4-alkadienals are largely the main responsible for a wide range of flavours in caviar from farmed white surgeon.

Authentication of farmed and wild turbot (Psetta maxima) by fatty acid and isotopic analyses combined with chemometrics.

Fatty acid composition and stable isotope ratios of carbon (delta(13)C) and nitrogen (delta(15)N) were determined in muscle tissue of turbot (Psetta maxima). The multivariate analysis of the data was performed to evaluate their utility in discriminating wild and farmed fish. Wild (n=30) and farmed (n=30) turbot of different geographical origins (Denmark, The Netherlands, and Spain) were sampled from March 2006 to February 2007. The application of linear discriminant analysis (LDA) and soft independent modeling of class analogy (SIMCA) to analytical data demonstrated the combination of fatty acids and isotopic measurements to be a promising method to discriminate between wild and farmed fish and between wild fish of different geographical origin. In particular, IRMS (Isotope Ratio Mass Spectrometry) alone did not permit us to separate completely farmed from wild samples, resulting in some overlaps between Danish wild and Spanish farmed turbot. On the other hand, fatty acids alone differentiated between farmed and wild samples by 18:2n-6 but were not able to distinguish between the two groups of wild turbot. When applying LDA isotope ratios, 18:2n-6, 18:3n-3, and 20:4n-6 fatty acids were decisive to distinguish farmed from wild turbot of different geographical origin, while delta(15)N, 18:2n-6, and 20:1n-11 were chosen to classify wild samples from different fishing zones. In both cases, 18:2n-6 and delta(15)N were determinant for classification purposes. We would like to emphasize that IRMS produces rapid results and could be the most promising technique to distinguish wild fish of different origin. Similarly, fatty acid composition could be used to easily distinguish farmed from wild samples.

Determination of astaxanthin stereoisomers and colour attributes in flesh of rainbow trout (Oncorhynchus mykiss) as a tool to distinguish the dietary pigmentation source

The presence of carotenoids in animal tissue reflects their sources along the food chain. Astaxanthin, the main carotenoid used for salmonid pigmentation, is usually included in the feed as a synthetic product. However, other dietary sources of astaxanthin such as shrimp or krill wastes, algae meal or yeasts are also available on the market. Astaxanthin possesses two identical asymmetric atoms at C-3 and C-3′ making possible three optical isomers with all-trans configuration of the chain: 3S,3′S, 3R,3′S, and 3R,3′R. The distribution of the isomers in natural astaxanthin differs from that of the synthetic product. This latter is a racemic mixture, with a typical ratio of 1:2:1 (3S,3′S:3R,3′S:3R,3′R), while astaxanthin from natural sources has a variable distribution of the isomers deriving from the different biological organism that synthesized it. The high-performance liquid chromatographic (HPLC) analysis of all-trans isomers of astaxanthin was performed in different pigment sources, such as red yeast Phaffia rhodozyma, alga meal Haematococcus pluvialis, krill meal and oil, and shrimp meal. With the aim to investigate astaxanthin isomer ratios in flesh of fish fed different carotenoid sources, three groups of rainbow trout were fed for 60 days diets containing astaxanthin from synthetic source, H. pluvialis algae meal and P. rhodozyma red yeast. Moreover, the distribution of optical isomers of astaxanthin in trout purchased on the Italian market was investigated. A characteristic distribution of astaxanthin stereoisomers was detected for each pigment sources and such distribution was reproduced in the flesh of trout fed with that source. Colour values measured in different sites of fillet of rainbow trout fed with different pigment sources showed no significant differences. Similarly, different sources of pigment (natural or synthetic) produced colour values of fresh fillet with no relevant or significant differences. The coefficient of distance computed amongst the feed ingredient and the trout fillet astaxanthin stereoisomers was a useful tool to identify the origin of the pigment used on farm.

Monola oil versus canola oil as a fish oil replacer in rainbow trout feeds: effects on growth, fatty acid metabolism and final eating quality.

Monola oil, a high oleic acid canola cultivar, and canola oil were evaluated as replacers of fish oil at three levels of inclusion (60%, 75% and 90%) in rainbow trout diets. After a 27-week grow-out cycle, the diet-induced effects on growth, fatty acid metabolism and final eating quality were assessed. Overall, no effects were noted for growth, feed utilisation or fish biometry, and the fatty acid composition of fish fillets mirrored that of the diets. Dietary treatments affected fillet lipid oxidation (free malondialdehyde), pigmentation and flavour volatile compounds, but only minor effects on sensorial attributes were detected. Ultimately, both oils were demonstrated to possess, to differing extents, suitable qualities to adequately replace fish oil from the perspective of fish performance and final product quality. However, further research is required to alleviate on-going issues associated with the loss of health promoting attributes (n-3 long chain polyunsaturated fatty acids) of final farmed products.

The relative absorption of fatty acids in brown trout (Salmo trutta) fed a commercial extruded pellet coated with different lipid sources

Abstract The objective of the present study was to investigate the fatty acid absorption capabilities of brown trout (Salmo trutta) fed commercial extruded diets. Five commercial extruded pellets, different only in the lipid sources used for fat coating, were tested on juvenile brown trout for 45 days. The trout were reared in fresh water at 14.6 ± 0.4° C and 7.7 ± 0.3 mg/l, temperature and dissolved oxygen, respectively. The tested lipid sources were fish oil, canola oil, oleine oil, swine fat and poultry fat. After the adaptation period faeces were collected by gently stripping from anaesthetized fish. Fatty acid analysis was performed on experimental diets and on collected faeces to evaluate the relative absorption capabilities of the trout digestive system with respect to each detected fatty acid. The use of the relative absorption efficiency (rAE) was opted to evaluate the intrinsic capability of each fatty acid to be absorbed. Brown trout showed a specific preferential order of absorption of the fatty acids, preferring shorter over longer chain fatty acids and preferring the more unsaturated to the more saturated fatty acids. The fatty acid that showed the best relative absorbability was the C18:4n-3 (rAE = 5.14 ± 0.72), which has a fairly short carbon chain, but at the same time a high unsaturation level, followed by the C18:3n-3 (rAE = 3.38 ± 0.30). The fatty acid that showed the worst relative absorbability (rAE = 0.21 ± 0.02) was C24:1n-9.

Discrimination of origin of farmed trout by means of biometrical parameters, fillet composition and flavor volatile compounds

Abstract To date it is well known that the quality of farmed trout is affected by diet composition, by feeding regime, by husbandry practices and by rearing conditions and environment. The trout processing industry and the large-scale retail trade, in consideration of the wide variability of trout quality and characteristics, have imposed, or will soon impose, quality criteria for the end product. Moreover, recent food scares and the malpractices of some food producers have increased public requests for traceability. The aim of the present study was to evaluate the main chemical quality and the biometrical characteristics of rainbow trout produced in three different farms in Italy (two intensive farms, located one on mountain and one on plain, and an extensive farm in which fish fed only on naturally available nutrients) and to establish whether farmed trout origins could be differentiated by these parameters. Trout farmed in the intensive mountain farm (IMF) showed the highest crude lipid content in the fillets and the fatty acids of their fillets were characterized by the highest percentage of MUFA. Trout farmed in the intensive plain farm (IPF) were characterized by low dressing percentage, and the lipid of their fillets was rich in n-6 fatty acids. Trout stocked for the last year of their life in the extensive farm (EF) were leaner both in the carcass and in the fillets. The analysis of flavor volatile compounds showed some differences in the bouquet design, particularly differences in the amounts of n-3 and n-6 derivates volatile aldehydes and alcohols. All data significantly different (P<0.05) were subjected to Linear Discriminant Analysis (LDA) and 8 variables were chosen to create two discriminant equations generating a strong prediction model for classification of farmed trout respective to their origins.

The impact of processing on amino acid racemization and protein quality in processed animal proteins of poultry origin

Re-authorization of processed animal proteins (PAPs) in EU, derived from by-products of human food production, could increase manufacturing of proteins for feed ingredients and reduce the need of imported proteins mainly of plant origin. The PAPs production is largely done by the rendering process during which authorized animal by-products are heat treated to extract valuable protein and animal fat, ensuring sterilizing conditions of raw incoming materials. Proteins exposure to certain processing conditions induces two important chemical changes, racemization of amino acids and formation of cross-linked amino acid. These changes are associated with appreciable reduction of protein digestibility and nutritional value. The aim of this study was to verify the effect of heat treatment on amino acid racemization in processed animal proteins of poultry origin and related nutritional implications by evaluation of their in vitro digestibility. The results reported confirm the detection of racemized amino acids in processed animal proteins, especially D-aspartic acid, as realistic indicators of thermal treatments during PAP manufacturing. In our results, the severe (115°C) and prolonged heat treatment (180 minutes) revealed a D-Asp content of 28.1%. Prolongation of temperature treatment (20, 30 and 180 min, at 115°C) significantly (P<0.05) affects in vitro protein digestibility, which decrease from 86.0%, in no-treated sample, to 78.3% and 79.1% after 20 and 30 min, respectively, and to 76.3% after 180 min. The processing conditions applied during PAPs preparations and the racemization of proteins amino acids may reasonably be involved in the loss of protein quality.