Tomislav Mašek

Production performance, meat composition and oxidative susceptibility in broiler chicken fed with different phenolic compounds

BACKGROUND Various studies have been conducted to evaluate the effect of phenolic compounds on production animals. Supplementation of animal diets with phytogenic compounds, such as different essential oils and polyphenols, could improve animal productivity as well as the chemical composition and oxidative stability of food derived from those animals. RESULTS During the trial, 80 male broilers of the Ross 308 strain were allocated to four dietary groups: control and three groups supplemented with thymol, tannic acid and gallic acid. Feed utilisation was improved in all experimental groups and tannic acid also improved final body weight. Gallic acid significantly increased n-3 long-chain polyunsaturated fatty acids. A hypocholesterolaemic effect was noticed in all groups in liver, but not in muscle. The glucose lowering effect in serum was noticed in the tannic acid group in comparison to other experimental groups. Oxidative susceptibility was improved by tannic acid in liver and breast and by gallic acid in breast muscle. CONCLUSION The inclusion of phenolic compounds enhanced growth performance, decreased lipid oxidation, decreased cholesterol value and increased beneficial fatty acids content. Positive effects varied depending on phenolic compound used and, therefore, it would be interesting to further investigate synergistic effects of investigated phenolic compound.

Long-term streptozotocin diabetes impairs arachidonic and docosahexaenoic acid metabolism and ∆5 desaturation indices in aged rats

We have investigated the long term effects of insulin dependent diabetes mellitus (IDDM) on the fatty acid profile of tissues in aging rats. For this purpose, a rat model for IDDM was established by streptozotocin application. The rats were randomly divided into four groups of 8 animals each: CON 6 (control group sacrificed after 6 months of the experiment), CON 12 (control group sacrificed after 12 months of the experiment), DM 6 (streptozotocin treated and sacrificed after 6 months of diabetes) and DM 12 (streptozotocin treated and sacrificed after 12 months of diabetes). The periods of 6 and 12 months were taken to observe the changes in lipid metabolism for chronic, long-term diabetes. Fatty acid profiles of the liver and skeletal muscle total lipids and phospholipids as well as desaturation indices for ∆6 desaturase (D6D), ∆5 desaturase (∆6D), ∆9 desaturase (∆9D) and de novo lipogenesis index (DNL) were estimated. Additionally the long-term effects (12 months) were tested in the brain, perirenal fat and bone marrow. The fatty acid composition of lipids was altered in IDDM rats in all tested tissues. The desaturation indices revealed the expected significant decrease in ∆9D and ∆5D indices in tested tissues, while indices for ∆6D were not influenced by diabetes. DNL revealed the strong inhibition of de novo lipogenesis in the liver tissue. Values for arachidonic C20:4n6 (arachidonic acid) significantly decreased in liver total lipids in DM 6 and DM 12 groups and in phospholipids in the DM 12 group. Surprisingly, values for C20:4n6 were also significantly lower in the brain tissue in the DM 12 group. Accumulation of C20:4n6 precursors (C18:2n6 and C20:3n6) was visible in all tissues. Docosahexaenoic acid (C22:6n3) significantly decreased in liver total lipids, liver phospholipids and in the brain phospholipids of the DM 12 group. The present results show that age could exacerbate the expected decrease in the liver synthesis of C20:4n6 in IDDM. Moreover, long-term diabetes could impair C22:6n3 synthesis in the liver and muscle, and incorporation of both important fatty acids into brain phospholipids. In conclusion, numerous changes in fatty acid composition are caused by long-term diabetes in aged rats. These changes could be involved in the pathogenesis of senile and diabetes-induced damage. The results could have clinical significance due to the increasing age of diabetic patients.

Blood biochemical parameters of crossbred Istrian x East Friesian dairy ewes: relation to milking period

Abstract The research was conducted to investigate the serum biochemistry values for crossbred Istrian x East Friesian dairy ewes and additionally to test the effects of the milking period on biochemistry values. The values could be used for monitoring metabolic status and breeding program. Biochemical values for crossbred Istrian x East Friesian dairy ewes were derived from one hundred and twenty ewes raised in the Mediterranean region of Croatia. The milking period was divided into early, mid and late milking periods in order to examine the effects of the milking period on biochemical values. The concentrations of calcium, phosphorus, magnesium, blood urea nitrogen (BUN), creatinine, glucose, total protein, albumin, globulin, total lipids, triglycerides, cholesterol, beta-hydroxy-butirate as well as aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl-transferase (GGT), alkaline phosphatase (ALP), and creatine phosphokinase (CK) activities were examined.

The effects of castration on the growth parameters, carcass yield and meat chemical composition of intensively reared Common Pheasant (Phasianus colchicus colchicus L.)

Abstract The effects of castration on growth performance, carcass characteristics and chemical composition of m. iliotibilais cranialis and m. pectoralis superficialis of pheasants were examined. Forty pheasants reared in commercial pheasantry were included in the experiment. Half of the pheasants were castrated at 8 weeks of age. Values for live weight tended to be higher in castrated pheasants in the 24th week (P<0.1) and values for weight gain were significantly higher between the 16th and 24th weeks (P<0.05). Feed-to-gain-ratio (8th – 32nd week) was significantly better (P<0.05) in castrated pheasants. Eviscerated weight and dressing percentage at 32nd week were not significantly different between treatments. The chemical composition of m. iliotibilais cranialis and m. pectoralis superficialis showed significantly higher values of fat (P<0.01) and moisture (P<0.05) in castrated pheasants in comparison with intact ones. Protein content of both muscles was higher in intact pheasants (P<0.05). Body part weights were not influenced by the treatment with the exception of heart weight, which was significantly higher in the intact pheasants (P<0.05). We concluded that castration tended to improve growth performance only in the first 24 weeks of the fattening period and, therefore, continuation of fattening after that period is no longer feasible. The most important characteristic of the castrated pheasant’s meat was an increased amount of fat. More studies under different feeding and alternative breeding systems are necessary to improve production.

Gender and gonadectomy influence on neurons in superior cervical ganglia of sexually mature rats.

Gonadal hormones have a significant influence on both the number of neurons and the density of synapses in the superior cervical ganglion (SCG) during the early postnatal period. There are no studies reporting influence of the absence of these factors in sexually mature animals, although changes in SCG-neurons of the rat were observed up to 6 months of age. Hence, we investigated whether gonadectomy of sexually mature rats influences morphological properties of neurons in the SCG of the rat and if so, would it have a specific effect on neurochemically distinct subpopulations. Male and female Sprague-Dawley rats were gonadectomized at the age of two months. After 30 days, they were sacrificed and SCGs were harvested and processed immunohistochemically. The mean diameter of NPY- neurons was greater in male rats, in comparison to all other groups (p<0.05). The number of NPY+, NPY- and total neurons per section area was significantly higher in female than in male, orchidectomized or the ovariectomized animals (p<0.05). The share of the different neuronal populations in the SCG that were encircled with calretinin-positive baskets (c.b+) or c.b.- (NPY+ or NPY-) was significantly influenced by the gender of the animals and gonadectomy, with significantly more c.b.+ in male animals (p<0.05). Results of the present study indicate that substantial changes in the SCG neurons of the rat occur after reaching sexual maturity, and are influenced by the gonadectomy.

Tissue fatty acid composition and estimated ∆ desaturase activity after castration in chicken broilers fed with linseed or sunflower oil

The aims of this study were to investigate the influence of the short-term addition of sunflower and linseed oil and castration on fatty acid composition and desaturation indexes in chicken broilers. Forty-eight male Ross 308 chicken broilers were supplemented with 5% of sunflower or linseed oil. The four experimental groups were linseed oil supplementation and castration (LC), linseed oil without castration (LN), sunflower oil and castration (SC) and sunflower oil without castration (SN). There was no significant influence of castration or oil supplement on live weights, weight gain, feed intake or feed conversion. Castration resulted in an increase in polyunsaturated fatty acids (PUFA), total n3, n6, measured desaturation indexes and a decrease in the saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) content of abdominal fat. In breast muscle, castration increased PUFA and 18:3n3 values, while in the liver tissue, castration did not influence the parameters measured. Linseed oil supplementation significantly increased 18:3n3, n3 long chain polyunsaturated fatty acids (LC PUFA), total n3 and decreased total n6, n6/n3 ratio, and 20:4n6 content. Values for 20:4n6 were the highest in SC and the lowest in the LC group. Linseed oil also significantly decreased ∆5 and ∆4 desaturation indexes in the thighs and ∆5 and ∆5, 6 in abdominal fat and the liver. These results suggest that short-term supplementation of basal diet with 5% of linseed oil could significantly increase n3 LC PUFA and decrease n6/n3 ratio content in the edible tissues of chicken broilers, without adverse effects on growth performance. Meanwhile, castration only improved fatty acid profile in abdominal fat, which is not nutritionally important. The interactions observed between basal diet, supplemented oil, sex hormones and other non-nutritional factors must be elucidated in future trials in order to correctly predict the nutritional value of linseed-fed poultry.

Liver enzymes and blood metabolites in a population of free-ranging red deer (Cervus elaphus) naturally infected with Fascioloides magna

We investigated the effects of Fascioloides magna infection on the serum biochemistry values of the naturally infected red deer population in eastern Croatia. The investigation was performed on 47 red deer with F. magna infection confirmed patho-anatomically in 27 animals (57.4%). Fibrous capsules and migratory lesions were found in 14 deer while only fibrous capsules without migratory lesions were found in 13 deer. In 13 deer both immature and mature flukes were found, in 5 deer only immature flukes were found and in 9 deer only mature flukes were found. Fascioloides magna infected deer with fibrous capsules and migratory lesions had significantly higher values for lactate dehydrogenase (LDH), glutamate dehydrogenase (GLDH) and globulin, and lower values for albumin/globulin ratio and glucose compared to uninfected deer. Fascioloides magna infected deer with fibrous capsules without the presence of migratory lesions had higher values for alanine aminotransferase (ALT) and globulin, and lower values for albumin/globulin ratio and glucose, than the uninfected deer. The number of immature flukes was positively correlated with values of aspartate aminotransferase (AST), γ-glutamyltransferase (GGT), LDH, GLDH, urea and triglycerides. The number of migratory lesions was positively correlated with GGT, GLDH, globulin and urea values. The creatinine value was positively correlated with the number of mature flukes. The trial showed that F. magna infection causes significant changes in serum biochemistry. Moreover, these changes do not completely resemble changes following F. hepatica infection. Further investigation of changes in liver enzymes and other serum metabolites in controlled, experimentally induced fascioloidosis in red deer is needed to better understand the pathogenesis of F. magna.

Expression of PTHrP and PTH/PTHrP receptor 1 in the superior cervical ganglia of rats.

PTHrP and its receptor PTHR1 are found in the CNS and peripheral nervous system. The presence of PTHrP mRNA has been detected in the superior cervical ganglion (SCG), but there are no data on the cellular distribution of PTHrP and PTHR1 in the SCG. Although it is known that ovarian activity and reproductive status influence sympathetic activity, and the PTHrP/PTHR1 system is influenced by estrogens in different tissues, it is not known whether these factors have a similar effect on expression of PTHrP and PTHR1 in the nervous system. Hence, we investigated the presence and distribution of PTHrP and PTHR1 in neurons and glia of the SCG of rats, as well as the influence of ovariectomy on their expression, by using immunohistochemistry. PTHrP and PTHR1 immunoreactivity was observed in cytoplasm as well as in nuclei of almost all neurons in the SCG. In male rats, intensity of PTHrP fluorescence was significantly higher in cytoplasm of NPY-, in comparison to NPY+ neurons (p < 0.05). In female rats, 2 months post-ovariectomy, significantly lower intensity of PTHrP fluorescence in cytoplasm of the SCG neurons was observed in comparison to sham operated animals (p < 0.05). In addition to neurons, PTHrP and PTHR1 immunoreactivity was observed in most of the glia and was not influenced by ovariectomy. Results show the expression of PTHrP and its receptor, PTHR1, in the majority of neurons and glial cells in the SCG of rats. Expression of PTHrP, but not PTHR1 in the cytoplasm of SCG neurons is influenced by ovarian activity.

Serologic evidence of Leptospira spp. serovars in brown bears (Ursus arctos) from Croatia.

Serum samples from 52 free-ranging brown bears (Ursus arctos) collected in Croatia over a period of 10 yr (1998–2007) were tested by microscopic agglutination test for specific antibodies (Ab) to 12 Leptospira spp. pathogenic serovars. At titers ranging from 1:100 to 1:2,000, 19 samples (36.5%) were Ab-positive to at least one serovar. Antibodies for 10 Leptospira spp. serovars were detected: Icterohaemorrhagiae, Australis, Sejroe, Canicola, Poi, Hardjo, Ballum, Saxkoebing, Pomona, and Grippotyphosa. In comparison to previous reports, the prevalence of Ab to serovar Icterohaemorrhagiae (52.6%) was significantly higher. Other common serovars were Australis (47.4%) and Sejroe (42.1%). High Ab titers for serovars Canicola (1:500) and Grippotyphosa (1:1,000) were detected for the first time in free-ranging bears from Croatia. A significant correlation between the age of the bears and detection of Ab to Leptospira spp. serovars suggested the presence of pathogenic agents in the natural habitats, whereas increasing trends of Ab prevalence for specific serovars (Icterohaemorrhagiae, Australis, and Sejroe) confirmed cohabitation of bears with rats and other small terrestrial mammals on garbage dumps and at bear feeding stations. To prevent cohabitation of bears and rodents, improvements in Croatian waste treatment, big game management, and rodent control programs are strongly recommended, especially in Lika and Gorski Kotar, regions that have high-quality natural habitats for brown bears in Croatia.

Hematology and serum biochemistry of European mouflon (Ovis orientalis musimon) in Croatia.

The aim of the present study was to determine the reference intervals for the most commonly used hematological and biochemical parameters of European mouflon from a closed hunting ground in the eastern part of the Republic of Croatia. Blood samples were collected from 39 live, physically restrained, clinically normal European mouflon, as well as from 50 domestic sheep. The distribution of values within each parameter was determined and statistical differences in values between sexes were also determined. For each sample, 14 hematological and 18 biochemical parameters were analyzed. Hematology and biochemistry values of the European mouflon were also compared with the values of domestic sheep. In further studies, the established values might be useful for the health assessment of mouflon.