First Description of Partial Atrioventricular Septal Defect in a Rabbit

Congenital heart diseases have rarely been described in rabbits. The purpose of the present case report is to describe the clinical, radiographic, echocardiographic, and pathological features of a partial atrioventricular septal defect in a pet rabbit. A 3-month-old, 380-g male vaccinated pet rabbit was presented for decreased activity, increased respiratory rate and effort, anorexia, and decreased fecal output of 2 days duration. Total body radiographic images revealed severe cardiomegaly associated with enlarged caudal pulmonary vessels and increased interstitial to alveolar lung pattern. Echocardiographic imaging showed evidence of distended heart chambers, abnormal flow through the atria, and mitral valve regurgitation. The rabbit was treated with furosemide and an angiotensin-converting enzyme inhibitor but rapidly deteriorated and died. Necropsy confirmed the dilation of both ventricles and the presence of a partial atrioventricular septal defect associated with an ostium primum atrial septal defect just over the tricuspid valve and the mitral valve.     

Protein and lipid oxidation during frozen storage of rainbow trout (Oncorhynchus mykiss)

This study aimed at investigating protein and lipid oxidation during frozen storage of rainbow trout. Rainbow trout fillets were stored for 13 months at -20, -30, or -80 degrees C, and samples were analyzed at regular intervals for lipid and protein oxidation markers. Lipid oxidation was followed by measuring lipid hydroperoxides (PV), as well as secondary oxidation products (volatiles) using dynamic headspace GC-MS. Free fatty acids (FFA) were measured as an estimation of lipolysis. Protein oxidation was followed using the spectrophotometric determination of protein carbonyls and immunoblotting. Significant oxidation was observed in samples stored at -20 degrees C, and at this temperature lipid and protein oxidation seemed to develop simultaneously. FFA, PV, and carbonyls increased significantly for the fish stored at -20 degrees C, whereas the fish stored at -30 and -80 degrees C did not show any increase in oxidation during the entire storage period when these methods were used. In contrast, the more sensitive GC-MS method used for measurement of the volatiles showed that the fish stored at -30 degrees C oxidized more quickly than those stored at -80 degrees C. Detection of protein oxidation using immunoblotting revealed that high molecular weight proteins were oxidized already at t = 0 and that no new protein oxidized during storage irrespective of the storage time and temperature. The results emphasize the need for the development of more sensitive and reliable methods to study protein oxidation in order to gain more explicit knowledge about the significance of protein oxidation for food quality and, especially, to correlate protein oxidation with physical and functional properties of foods.     

Characterization of oxidative changes in salted herring (Clupea harengus) during ripening

Salted herring were prepared in barrels according to a traditional recipe. The biochemical changes in the fish and in the brine were monitored during a prolonged ripening period (12 months). The process was followed by measuring pH, protein, salt, dry matter, free fatty acids, and lipid content in the brine and in the fish according to standard protocols. The results showed that most of the biochemical changes occurred at an early stage in the ripening process. Lipid oxidation was followed in the fish muscle using spectroscopic determination for lipid hydroperoxide (PV) and by GC-MS for determination of secondary oxidation products. Protein oxidation was determined using spectrophotometric determination of protein carbonyl groups. To follow protein degradation (proteolysis) and protein oxidation SDS-PAGE and immunoblotting for protein carbonyl were performed on both brine and fish during the ripening period. Results revealed that no lipid oxidation occurred in fish muscle during ripening but a significant level of protein oxidation was detected. Finally, iron alpha-tocopherol, and 3-methylbutanal levels were also measured. Alpha-tocopherol levels decreased during ripening, further supporting that oxidative reactions took place. Peroxidase activity was demonstrated in the brine, suggesting that hemoglobin might be a crucial parameter, which might trigger protein oxidation. This indicates that protein oxidation might be important for the development of the characteristic organoleptic properties of salted herring.     

Enzymatic degradation of cell wall polysaccharides from mango (Mangifera indica L.) puree

Ripe mango puree (Smith cultivar) was treated with fungal polysaccharidases containing pectinolytic, hemicellulolytic, and cellulolytic activities for 2 h at 50 degrees C. A loss of 30% of the cell wall material (CWM) was measured. CWM polysaccharides were hydrolyzed to varying degrees: 88, 65, and 65% of, respectively, galacturonic acid-, arabinose-, and rhamnose-containing polymers were hydrolyzed, whereas 50% of cellulose was degraded. After 30 min of treatment, the ethanol precipitation test on the serum was negative, indicating that pectic substances were rapidly hydrolyzed. Oligogalacturonic acids (degree of polymerization, 1-12) were observed in the serum. A viscosity drop of 90% was measured after 2 h, confirming the dominant role of pectic substances in puree viscosity.