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.

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.

Comparison of the performances of Nero Siciliano pigs reared indoors and outdoors: 2. Joints composition, meat and fat traits.

A study on the effect of rearing system on tissue composition of principal joints and chemical-physical traits of meat and subcutaneous fat, was carried out on a local pig breed. A total of 78 Nero Siciliano pigs was used; 41 pigs were reared in woods, 37 pigs were reared in pens and fed a commercial diet. Weight at slaughter was 101.9 and 88.2 kg for indoor and outdoor pigs, respectively. Means were estimated at 77 kg of live weight. At ham dissection outdoor-pigs showed higher percentages of lean (58% vs. 55%) and lower subcutaneous fat (31% vs. 34%). In Longissimus lumborum outdoor-pigs showed a higher intramuscular fat percentage (4.3% vs. 3.3%), a lower protein content (22.2% vs. 23.4%), and higher free water (9.6 vs. 7.9 cm(2)). Outdoor pigs produced more light (L(*)=50 vs. 46.7) and more yellow (b(*)=5.84 vs. 4.88) meat. Subcutaneous fat of outdoor pigs showed higher percentages of MUFA (53.3% vs. 47.2%) and lower percentages of PUFA (10.85% vs. 14.45%), no differences were found for n-3 PUFA. Outdoor-pigs had lower atherogenicity (0.48 vs. 0.53) and thrombogenicity (1.03 vs. 1.21) indices.

Identification of species in animal feedstuffs by polymerase chain reaction--restriction fragment length polymorphism analysis of mitochondrial DNA.

Restriction site analysis of Polymerase Chain Reaction (PCR) products of cytochrome b mitochondrial DNA was applied to identify species in meat meal and animal feedstuffs. PCR was used to amplify a variable region of cytochrome b mitochondrial DNA gene. Species differentiation was determined by digestion of the obtained 359 bp amplicon with restriction enzymes, which generated species-specific electrophoresis patterns; the sequencing of PCR products was used as confirming analysis. PCR-RFLP analysis revealed the presence of meat meal in animal feedstuffs and distinguished species of interest. The results supported the application of the method in control measures which should be adopted for meat-meal-based animal feed, as suggested by EU law. As a technical improvement, to simplify the analysis, the number of enzymes presented in this study for the detection of different species was smaller than others described in the literature; discrimination between ruminant and nonruminant species and between mammalian and poultry species was possible with few digestions.

Racemization kinetics of aspartic acid in fish material under different conditions of moisture, pH, and oxygen pressure.

The racemization kinetics of aspartic acid in heat-treated whole herring have been studied under conditions of treatment comparable to those that may occur in processing of fish meal. D-Aspartic acid content in the samples has been measured by RP-HPLC with precolumn automatic derivatization. The major parameters affecting the rate of racemization of aspartic acid k(Asp) have been demonstrated to be temperature (elevation of temperature from 95 to 120 degrees C resulted in an increase of k(Asp) from 0.46 to 3.39x10(-3) min(-1)), moisture of the raw material (reduction of the moisture content of the raw material from 80 to 15% lowered k(Asp) measured at 95 degrees C from 0.46 to 0.06x10(-3) min(-1)), and to a lesser extent, pH (k(Asp) at 95 degrees C was lowered from 0.46 to 0.37x10(-3) min(-1) following a decrease of pH from 7.0 to 4.0). No significant effects on the racemization rate of aspartic acid was observed for reducing the oxygen pressure to 0.8%. The results from the present study show that the content of D-aspartic acid in fish material is a function of heat exposure and may be used to predict the thermal history of fish meal.

High-performance liquid chromatographic determination of polyamines in milk as their 9-fluorenylmethoxycarbonyl derivatives using a column-switching technique.

A high-performance liquid chromatographic method for the determination of polyamines in milk is milk is described. Polyamines were extracted in perchloric acid and derivatized with 9-fluorenylmethoxycarbonyl chloride (FMOC-Cl). The excess of reagent was reacted with aspartic acid before the analysis on a column-switching system. Linearity of derivatization was calculated for each amine and the coefficient of regression ranged from 0.994 to 0.999. Chromatographic separation of FMOC-polyamines was achieved with a gradient elution programme of water-acetonitrile. The correlation coefficients of the standard curves in the concentration range from 0.5 to 5 nmol ml-1 were higher than 0.991. The repeatability of the method, expressed as R.S.D. for each polyamines ranged from 3.0 to 8.6%. The percent mean recoveries at 1 nmol ml-1 spiking level were 49 +/- 3, 58 +/- 5, 61 +/- 5 and 48 +/- 4 for putrescine, cadaverine, spermidine and spermine, respectively. The limit of detection, calculated on the basis of three times signal-to-noise ratio, was 50 pmol ml-1 for each polyamine.

High-performance liquid chromatographic determination of oxytetracycline in channel catfish (Ictalurus punctatus) muscle tissue.

A high-performance liquid chromatographic method for the determination of oxytetracycline in channel catfish muscle tissue is presented. Oxytetracycline is extracted three times from muscle tissue with an ethylenediaminetetraacetic acid disodium salt-McIlvaine buffer (pH 4.0) by using an Ultra Turrax. Analysis is carried out by using high-performance liquid chromatography and an acetonitrile-oxalic acid (0.05 mol 1(-1), pH 2.2) mixture (14 + 86, v/v) is used as mobile phase. Oxytetracycline is separated on a Lichrosorb RP-8 125 x 4.0 mm i.d. column and ultraviolet detection at 355 nm is used. The limit of quantification is 10 ng g-1 and the linearity, tested in the spiking range 20-500 ng g-1, is 0.9997. Recovery from muscle spiked at 20, 50, 100, 200 and 500 ng g-1 levels is in the range 70-80%. Precision, expressed as percentage relative standard deviation, is below 7%. The method is applied to muscle tissue from channel catfish fed on a medicated diet.

Effect of temperature and diet composition on residue depletion of oxytetracycline in cultured channel catfish.

Oxytetracycline is an antibacterial agent widely used in fish farming. The normal method of administration of oxytetracycline to the fish is to mix the drug into the feed. As a consequence, the concentration of the drug in feed, together with the preparation and the composition of feed, can influence the disposition of the drug itself. An experimental study was carried out to evaluate the residue depletion of oxytetracycline from muscle tissue of channel catfish (Ictalurus punctatus) fed different medicated diets. Three hundred channel catfish were randomly divided into six tanks (50 fish per tank), maintained at water temperatures of 18 degrees C (three tanks) and 23 degrees C (three tanks). The animals were fed with three diets, differing in their energy content and composition, for the duration of the experiment oxytetracycline was added to the diets at a level of 7500 mg kg-1 for 7 d. After cessation of the treatment, five fish from each tank were killed on days 1, 3, 8, 13, 18, 24, 30, 35 and 40. Oxytetracycline residues in muscle tissue were determined by high-performance liquid chromatography. The results indicate that the energy level and chemical composition of the medicated diets administered to channel catfish influence oxytetracycline disposition in fish, and that temperature is an important factor in conditioning the reported dietary effects. Therefore, formulation of specific diets to administer drugs to farmed fish could assure better bioavailability of the chemotherapeutant and shorter withdrawal times.

Automated high-performance liquid chromatographic determination of chloramphenicol in milk and swine muscle tissue using on-line immunoaffinity sample clean-up.

An on-line high-performance liquid immunoaffinity chromatographic (HPLIAC) system for the direct determination of chloramphenicol in milk and swine muscle tissue is described. The system consisted of a dual-column system in which an HPLIAC column was directly coupled to an RP-8 high-performance liquid chromatographic column. Skimmed and deproteinated milk or aqueous muscle tissue extract was directly injected into the HPLIAC column. After a washing step with phosphate-buffered saline, chloramphenicol was desorbed by a glycine-NaCl buffer (pH 2.8) and directly concentrated on the RP-8 column. Next, chromatography was carried out using acetonitrile-sodium acetate buffer as the mobile phase. Chloramphenicol was detected at 280 nm. Mean recoveries from spiked raw milk were 70 +/- 2% (1-50 micrograms/kg) and from spiked swine muscle tissue 64 +/- 2% (10-50 micrograms/kg). The calibration curves were linear in the range 1-200 micrograms/kg spiking levels. Limits of determination were 1 microgram/kg for milk and 10 micrograms/kg for muscle tissue.

Treatment of infections by staphylococci and other gram-positive bacteria with teicoplanin: an open study.

Teicoplanin, 200-400 mg (3-6 mg/kg) daily iv or im, was used to treat 71 episodes of infection. The average duration of treatment was 22 days. The 64 evaluable episodes comprised 24 skin/soft tissue, 20 osteoarticular, ten urinary tract and one ventriculo-atrial shunt infections; one case of primary bacteraemia, three of endocarditis, two of pneumonia and three of pleural empyema. Fifty-five episodes were treated with teicoplanin monotherapy and nine with teicoplanin in association to other antibiotics. Overall 61% (39/64) of the evaluable infections were cured, 25% (16/64) improved and 14% (9/64) failed. Staphylococcus aureus was the most frequent pathogen, with 46 isolates. Infections by both methicillin-sensitive and resistant Staph. aureus strains showed favourable clinical and microbiological responses to teicoplanin. Side effects were observed in eight of the 64 episodes (12.5%). Bronchospasm was observed in two other cases at the beginning of therapy and the antibiotic administration was discontinued. Teicoplanin is an effective and well tolerated antibiotic for infections by Gram-positive bacteria, and it is effective against methicillin-resistant staphylococci.