Automated image analysis as a tool to quantify the colour and composition of rainbow trout (Oncorhynchus mykiss W.) cutlets

The goal of this paper is to propose and evaluate automated image analysis methods for describing muscle cutlets in rainbow trout. The proposed automated image analysis methods were tested on a total of 983 scanned images of trout cutlets, and included quality traits such as fat percentage, flesh colour and the size of morphologically distinguishable subparts of the cutlet. A sub-sample of 50 images was randomly selected for manual segmentation of the cutlet, the dorsal fat depot and the red muscle and regions. The identification of these regions by manual and automatic image analysis correlated strongly (r = 0.97, r = 0.95 and r = 0.91, respectively). The estimated fat percentage obtained from image analysis, based on the area of visible fat and the colour of the cutlet flesh, correlated well with chemical fat percentage measured by mid-infrared transmission spectroscopy (MIT) (r = 0.78). The automated image analysis methods are therefore a reliable means of predicting the fat percentage of trout cutlets. Principal component analysis (PCA) loading plots were used to identify subsets of variables from the image analysis of special significance for further studies; cutlet area, dorsal fat depot area, red muscle area, back height, cutlet width, and width of left and right abdomen wall were among the variables selected. PCA loading plots of different colour variables indicated that simple statistical coefficients such as percentiles and mean values can be used to quantify different aspects of flesh colour. In conclusion, the methods presented here provide a powerful toolbox for describing important morphological structures and quality traits of trout cutlets.     

Effect of lipid source and bile salts in diet of Atlantic salmon, Salmo salar L., on astaxanthin blood levels

A study was conducted to determine the effects of dietary lipid and bile acids on astaxanthin absorption in Atlantic salmon (Salmo salar L.). Fish with an average weight of 1500 g were fitted with a dorsal aorta cannula and fed diets containing herring oil, soybean lecithin, lard, or herring oil supplemented with taurocholic acid (2.5 g/kg diet). Each fish was fed all of the experimental diets in successive order to minimize the effect of individual variation. At a given time following the feeding of each diet, blood was collected and analyzed for astaxanthin. Soybean lecithin significantly lowered the absorption of astaxanthin compared to fish fed herring oil. A 20% (p < 0.12) increase in blood astaxanthin was observed when the fish were fed the diet supplemented with taurocholic acid. Feeding lard significantly increased the blood astaxanthin level compared to the control group. It appears that altering the micellar structure by stimulating micellar (taurocholic acid) or mixed micellar (lecithin) systems did not increase the apparent absorption of astaxanthin. However, increasing the phospholipid level may have actually decreased the absorption possibly by lowering the astaxanthin solubility in the micelles. The increased apparent absorption of astaxanthin with lard is possibly linked to the increased content of 16:0, 18:1n − 9 or 18:2n − 6 fatty acids in this diet, or a reduction in very long chain monoenes (20:1n − 9 and 22:1n − 9). This suggests that the solubility of astaxanthin is higher in diets containing higher levels of 16:0 or 18:1n − 1, or alternatively, that reductions in longer chain monoenes (20:1n − 9 and 22:1n − 9) increase the micellar solubility of this pigment.     

Changes in arterial PO₂, physiological blood parameters and intracellular antioxidants in free-swimming Atlantic cod (Gadus morhua) exposed to varying levels of hyperoxia

Free-swimming Atlantic cod (Gadus morhua) were exposed to water oxygen pressures (P _wO₂) ranging from 18.1 to 41.5 kPa and sampled for blood using an indwelling caudal artery cannula. Arterial blood oxygen pressure (P _aO₂) increased with increasing P _wO₂, from 12.0 kPa in normoxia (18.1 kPa) to 34.2 kPa in the highest hyperoxic level tested (41.5 kPa). Blood CO₂ pressure and plasma bicarbonate concentration increased with P _wO₂, indicating reduced ventilation with increased P _wO₂. Plasma glucose, sodium and potassium were not affected by water oxygen level. Blood oxidative stress biomarkers, reduced glutathione, oxidized glutathione and the oxidative stress index (ratio between oxidized and total glutathione) differed intermittently between normoxia and hyperoxia. The oxidative stress index was higher in the blood of exposed compared to unexposed control cod. Together with elevated P _aO₂, these findings suggest increased production of reactive oxygen species and increased oxidative stress in Atlantic cod exposed to hyperoxia.     

Low-Temperature Nonoxidative Activation of Methane over H-Galloaluminosilicate (MFI) Zeolite

Conversion of methane to higher hydrocarbons by its low-temperature activation without forming undesirable carbon oxides is of great scientific and practical importance. Methane can be highly activated, yielding high rates of conversion to higher hydrocarbons and aromatics (10 to 45 percent) at low temperatures (400° to 600°C), by its reaction over H-galloaluminosilicate ZSM-5 type (MFI) zeolite in the presence of alkenes or higher alkanes. The methane activation results from its hydrogen-transfer reaction with alkenes.     

Changes in demand feeding behaviour in Arctic charr, Salvelinus alpinus L., caused by differences in dietary energy content and reward level

The objective of this study was to determine whether Arctic charr, Salvelinus alpinus L., are able to adjust their demand feeding behaviour in accordance to differences in dietary energy content (experiment 1) and reward level (amount of food received in response to one trigger actuation) (experiment 2). Fish (initial size 215 g in experiment 1 and 88 g in experiment 2) were reared in 0.8-m³ indoor tanks at commercial stocking densities and fed using demand feeders for 57 and 180 days, respectively. Demand feeding activity did not differ significantly between groups of charr fed diets with a low (19.8 MJ kg^-1) gross energy content and those given high-energy (22.0 MJ kg^-1) feed. As a result, fish offered the high-energy diets grew significantly faster. The results show that charr held under culture conditions are unable to adjust their demand feeding activity based on the energy content of the food. On the contrary, Arctic charr are able to adjust their demand feeding activity to either low (0.33 g), medium (0.87 g) or high (1.52 g) rewards, and thereby, regulate their food supply to fit their needs. However, it took about 90 days before charr in the low-reward treatment released a daily food ration as high as that released in the high-reward groups. Consequently, there was a significant positive relationship between the size of the reward and final weights. To avoid any depression of initial growth rates, the optimal size of the reward should be 0.1 g per kg fish and trigger actuation.     

Liquid chromatographic determination of the estrogens daidzein, formononetin, coumestrol, and equol in bovine blood plasma and urine

A liquid chromatographic (LC) method is described for the determination of the plant estrogens diadzein, formononetin, and coumestrol and the estrogenically active metabolite equol in bovine blood plasma and urine. The blood and urine samples are incubated overnight with and without beta-glucuronidase/sulfatase for analysis of both free and conjugated forms of estrogens. Samples are applied to Extrelut columns, extracted with ethyl acetate, and evaporated to dryness. Residues from urine samples are dissolved in methanol, diluted with water, acidified with HCl, and purified by injection through a Sep-Pak C18 cartridge. This eluate is used for LC analysis. Residues from blood samples are dissolved in benzene-petroleum ether (1 + 1), extracted with ammonium hydroxide, acidified with glacial acetic acid, and extracted with ethyl acetate. The ethyl acetate extract is evaporated, dissolved in 80% methanol, injected onto a LC reverse-phase column, and separated in a linear gradient system between 40 and 80% methanol in phosphate buffer. Quantitation is performed by means of UV and fluorescence responses. The method was sensitive enough to determine 0.4 ng/mL of daidzein and formononetin and 0.1 and 13 ng/mL of coumestrol and equol, respectively, in blood, and 130, 80, and 7 ng/mL of daidzein, formononetin, and coumestrol, respectively, and 4 micrograms/mL of equol in urine. The applicability of the method was checked by the determination of total and free plant estrogens in blood samples from a dairy cow fed a normal diet.     

Spawning induces a shift in energy metabolism from glucose to lipid in rainbow trout white muscle

Enzymatic changes that occur in the white somatic muscle of rainbow trout (Oncorhynchus mykiss) in response to spawning were investigated, and the evenness of their distribution across the ventral-dorsal plane of this muscle was assessed. Four enzymes that are involved in energy metabolism were measured (phosphofructokinase: glycolytic capacity, 3-hydroxyacyl-CoA dehydrogenase: -oxidation, citrate synthase: citric acid cycle, cytochrome oxidase: oxidative capacity). The enzyme activities were followed in different parts of the white muscle of non-spawning female rainbow trout from May, four months after their first spawning, until December, at second spawning. Samples were taken from white epaxial muscle along the lateral line, on the dorsum, and in between. Samples were also taken from red muscle of non-spawning fish. The isoforms of myosin heavy chains (MyHC) were electrophoretically identified on 6% SDS-PAGE gel to study possible changes in contractile properties of the muscle.Transformation from the non-spawning to spawning phase was associated with dramatic changes in the activity of the enzymes studied in white muscle: glycolytic capacity decreased to less than half, whereas oxidative metabolism increased about two- to four-fold in all areas. Significant quantitative differences in enzyme activities were found between the three epaxial muscle areas: in the non-spawning fish lateral line samples differed from those taken in the other two areas, whereas in spawning fish the dorsal sample difered from the other two. No difference in the expression of MyHC-isoforms was found between spawning and non-spawning fish. Co-expression of both slow and fast isoforms was found in single fibres isolated from red muscle.The results show that the energy metabolism in white muscle of domestic rainbow trout is altered during spawning; i.e., the metabolism becomes increasingly aerobic, with an increased capacity for fatty acid utilization, concomitant with phenotypic changes associated with sexual maturation. These changes are especially pronounced in ventral, superficially located fibres.     

Production of Wild Buffalo (Bubalus arnee) Embryos by Interspecies Somatic Cell Nuclear Transfer Using Domestic Buffalo (Bubalus bubalis) Oocytes

The objective of this study was to explore the possibility of producing wild buffalo embryos by interspecies somatic cell nuclear transfer (iSCNT) through handmade cloning using wild buffalo somatic cells and domestic buffalo (Bubalus bubalis) oocytes. Somatic cells derived from the ear skin of wild buffalo were found to express vimentin but not keratin and cytokeratin‐18, indicating that they were of fibroblast origin. The population doubling time of skin fibroblasts from wild buffalo was significantly (p < 0.05) higher, and the cell proliferation rate was significantly (p < 0.05) lower compared with that of skin fibroblasts from domestic buffalo. Neither the cleavage (92.6 ± 2.0% vs 92.8 ± 2.0%) nor the blastocyst rate (42.4 ± 2.4% vs 38.7 ± 2.8%) was significantly different between the intraspecies cloned embryos produced using skin fibroblasts from domestic buffalo and interspecies cloned embryos produced using skin fibroblasts from wild buffalo. However, the total cell number (TCN) was significantly (p < 0.05) lower (192.0 ± 25.6 vs 345.7 ± 42.2), and the apoptotic index was significantly (p < 0.05) higher (15.1 ± 3.1 vs 8.0 ± 1.4) for interspecies than that for intraspecies cloned embryos. Following vitrification in open‐pulled straws (OPS) and warming, although the cryosurvival rate of both types of cloned embryos, as indicated by their re‐expansion rate, was not significantly different (34.8 ± 1.5% vs 47.8 ± 7.8), the apoptotic index was significantly (p < 0.05) higher for vitrified–warmed interspecies than that for corresponding intraspecies cloned embryos (48.9 ± 7.2 vs 23.9 ± 2.8). The global level of H3K18ac was significantly (p < 0.05) lower in interspecies cloned embryos than that in intraspecies cloned embryos. The expression level of HDAC1, DNMT3a and CASPASE3 was significantly (p < 0.05) higher, that of P53 was significantly (p < 0.05) lower in interspecies than in intraspecies embryos, whereas that of DNMT1 was similar between the two types of embryos. In conclusion, these results demonstrate that wild buffalo embryos can be produced by iSCNT.