Using trace elements in otoliths to discriminate between wild and farmed European sea bass (<Emphasis Type="Italic">Dicentrarchus labrax</Emphasis> L.) and Gilthead sea bream (<Emphasis Type="Italic">Sparus aurata</Emphasis> L.)

Trace elements in otoliths of sea bass (Dicentrarchus labrax L.) and sea bream (Sparus aurata L.) from fish farms and coastal wild populations in the western Mediterranean Sea were analysed by inductively coupled plasma-mass spectrometry. Results showed that concentrations of Mg, K, and Mn differed significantly between wild and farmed sea bass, while concentrations of Mg, K, Mn, Fe, Zn, Sr, and Ba varied significantly between wild and farmed sea bream. Discriminate analysis and cross-validation classification showed that the trace element profile in otoliths can be used to separate farmed fish from wild stocks with high accuracy on both sea bass (individuals correctly classified: 90.7 %) and sea bream (individuals correctly classified: 96.6 %). Moreover, trace elements in otoliths resulted to be useful to discriminate among wild fish stocks within each species.     

Influence of dietary enzyme complex on the performance of broilers fed on diets with and without antibiotic supplementation

1. The aim of the experiment was to test the possible interactions of an enzyme complex and a food antibiotic on the growth and metabolism, carcase yield, whole body composition and nutrient deposition in broilers. The basal diet contained 400 g/kg barley. The four treatments were as follows: O—without supplements (control), E—enzyme complex Roxazyme® G, 200 mg/kg, A—antibiotic avoparcin, 10 mg/kg, EA—Roxazyme G, 200 mg/kg plus avoparcin, 10 mg/kg.

2. Roxazyme G positively influenced weight gain, food conversion efficiency, energy metabolisability, fat and nitrogen utilisation and the dry matter content of droppings. Fat and energy deposition in the whole body were also increased, whereas protein deposition and carcase yield were not influenced.

3. Avoparcin increased energy metabolisability and fat utilisation, but had no influence on nitrogen utilisation. No significant improvements from avoparcin were seen in growth or in nutrient deposition in the body. The fibre degradability (NDF and ADF fraction) was significantly depressed by antibiotic supplementation.

4. The inclusion of both supplements to the diet did not have a fully additive effect on growth, energy metabolisability, or fat and nitrogen utilisation. The interaction between enzyme and antibiotic for food conversion efficiency during the first experimental period (7 to 21 d) was nearly significant (P= 0.053). Except for fibre degradability (P ≤ 0.01), no other significant interactions between enzyme and antibiotic were found.     

The Effect of Thermal Treatment Method on Fatty Acid Composition in Northern Pike (Esox lucius) Fillets

The aim of the present study was to investigate the effect of thermal treatment methods, such as microwave cooking, steaming, and shallow pan-frying on fatty acids composition in northern pike fillets. All methods of thermal treatment increased fat content in the fillets. Microwave cooking decreased the proportion of saturated fatty acids and increased the proportion of total, n-3, and n-6 polyunsaturated fatty acids as compared with fresh fillets. Steam cooking did not affect the proportion of saturated, monounsaturated, and polyunsaturated fatty acids, whereas pan-frying significantly increased the proportion of monounsaturated and n-6 polyunsaturated fatty acids. All cooked fillets, regardless of the thermal treatment used, had acceptable n–6/n–3 ratio; however, microwave cooking enabled fish products to obtain more beneficial n-6/n-3 ratio than frying. Due to high polyunsaturated fatty acids content and low n-6/n-3 ratio, microwave cooking may be recommended for preparing wild pike fillets in households.     

Dependence of the common carp (Cyprinus carpio L.) fatty acid profile on diet composition in a semi‐intensive farming system: tissue and time variability

Increasing the amount of n‐3 PUFA in carp meat is one of the most important tasks in enhancing its overall quality. However, the relative influence of supplemental feed and natural feed on the FA profile of cultivated carp flesh is not well documented, making it difficult to choose the most efficient strategy. Carp diet composition and diet and flesh fatty acid profiles were simultaneously followed in order to determine the influence of pelleted feed compared to natural feed on fatty acid profiles of carp tissues. Pelleted feed clearly dominated over zooplankton and Chironomidae in the carp diet, producing carp tissue fatty acid profiles closely resembling those of pelleted feed. However, increase in the abundance of zooplankton over the course of the investigation resulting in concomitant increase of its proportion in feed bulk was in strong positive correlation with increase in n‐3 HUFA in the dorsal muscle. n‐3 PUFA enrichment of supplemental feed could be the dominant mechanism in production of carp meat rich in n‐3 PUFA. However, even a small increase in natural feed availability could significantly change the diet of common carp and result in considerable improvement of meat quality with regard to n‐3 HUFA content.     

Composition and antifungal activity of the essential oil of Seseli annuum wild-growing in Serbia

The essential oil from the aerial parts of Seseli annuum, wild-growing in Serbia, was obtained by hydrodistillation and analyzed using GC and GC/MS. A total of 43 components were identified representing 96.5% of S. annuum oil. The most abundant compounds were germacrene D (29.8%), sabinene (10.3%), beta-ocimene Z (9.8%) and limonene (8.6%). The essential oil showed antifungal activity against fifteen fungi with MICs between 12.5 to 50 microl/ml.     

3D morphometric study of domestic fowl glomerulus—A scanning electron microscope study of vascular corrosion casts

Microvascularization of domestic fowl kidneys was studied using scanning electron microscopy (SEM) of vascular corrosion casts (VCCs). Two types of nephrons, mammalian-type (MT) and reptilian-type (RT) nephrons and their glomerular structure were analysed quantitatively by 3D morphometry. A significant difference in shape and size between the MT and RT glomeruli was found. The mean diameter of the RT glomeruli was about 56 µm, while that of MT glomeruli was significantly larger, namely about 80 µm. The afferent arterioles in mammalian-type glomeruli usually bifurcated into two lobular branches and formed a complex glomerular capillary network with numerous loops. Reptilian-type glomeruli consisted of a single capillary forming few loops and leaving the glomerulus as efferent arteriole. Diameters of afferent and efferent arteriolar replicas were similar in all three kidney divisions of MT and RT nephrons. The absence of the interconnecting branches between the MT nephron capillaries at the gross inspection suggests that the mammalian-type nephron glomeruli, although more complex than the reptilian type, are not equivalent to those in mammalian kidneys.     

Short-term effect of acarbose on specific intestinal disaccharidase activities and hyperglycaemia in CBA diabetic mice

The purpose of this study was to examine the short-term effects of 75, 100 and 150 mg of acarbose mixed in 100 g standard laboratory chow on specific intestinal disaccharidase activities and on hyperglycaemia in diabetic CBA strain mice on standard diet. The small intestine was excised and divided into three segments, from pylorus to duodenum, and two equal lengths of the jejunum and ileum of control and diabetic mice with or without added acarbose. Specific maltase and sucrase activities were determined using maltose and sucrose as substrates respectively. Increased specific activities of maltase and sucrase were detected in the intestines of CBA mice on standard laboratory diet seven days after alloxan-induced diabetes. Feeding for 7 days with 75, 100 or 150 mg acarbose uniformly mixed in 100 g standard laboratory chow, induced a decrease in the specific maltase and sucrase activities, compared with diabetic mice on standard laboratory diet. Feeding with 75 mg acarbose mixed in 100 g standard laboratory chow caused a statistically significant decrease of maltase in the duodenum and of sucrase in duodenum and jejunum, without a antihyperglycaemic effect. Feeding with 100 or 150 mg caused statistically significant decreases in specific maltase and sucrase activities in duodenum, jejunum and ileum. An antihyperglycaemic effect was observed only in the group of diabetic mice fed with 100 mg acarbose. This indicates that the antihyperglycaemic effect of acarbose involves factors other than these, related only to its inhibitory effect on disaccharidase activities.     

Endozoochory by European bison (Bison bonasus) in Białowieża Primeval Forest across a management gradient

We examined the year-round viable seed dispersal by European bison (Bison bonasus L.) subject to three population management systems (captive, semi-wild, wild) in Bia?owie?a Primeval Forest. The forest is inhabited by the world's largest free-roaming population of European bison (>450 head). Dung samples were collected approximately fortnightly from September 2005 to September 2006 in each of the management systems. Emergent seedlings were counted for 24 months in greenhouse conditions. A total of 10,807 seedlings, which included 178 plant taxa, emerged from 74 bison dung samples. Species richness and seedling abundance/sample were greatest during August and September, the months of the highest fructification season, and were lowest in May. Twenty-two percent of recorded species were forest plants. The captive bison population had the greatest mean seedling abundance (236 ± 61/sample), the greatest species diversity (144), and the highest percentage of synanthropic species (29.2%). The gradient of these characteristics decreased with a decrease in management intensity of the bison populations. The results of the regression analysis indicated that in the semi-wild managed system, the number of plant species found in dung samples collected during winter was significantly negatively correlated with snow depth. Number of seedlings and number of plant species dispersed depended on plant phenology and intensity of supplementary feeding. The mean number of seeds/sample dispersed by European bison was 5–15 times lower, and the mean number of species/sample was 2–3 times lower than those published for cattle or horses. In contrast, the total number of plant species dispersed by bison was approximately 2–3 times higher than for wild or domestic large ungulates. These results indicate that European bison are an important dispersal agent of seeds in forest ecosystems. The high percentage of synanthropic species dispersed by bison demonstrated that seeds in the fodder help maintain native and non-native plant diversity of ecosystems. Managers of animal populations must pay proper attention to fodder origin and quality.