Iosif Bizelis

Effect of vitamin E supplementation on neutrophil function, milk composition and plasmin activity in dairy cows in a commercial herd

Fifty-six Holstein dairy cows from a commercial dairy herd in the Northern part of Greece were used to determine the effect of vitamin E supplementation on immune parameters, milk composition and milk quality. Cows were assigned to one of two experimental groups: control (no vitamin E supplementation) and vitamin E supplementation. Supplementation of vitamin E started 4 weeks prior to and continued up to 12 weeks after parturition. Supplementation included daily oral administration of vitamin E at 3000 i.u./cow prepartum and was reduced to 1000 i.u./cow post partum. Blood samples were collected weekly for 8 weeks starting 4 weeks before parturition, neutrophils were isolated and the following parameters were determined in neutrophils activated by phorbol myristate acetate: total cell-associated and membrane-bound urokinase plasminogen activator (u-PA) activity and superoxide production. Milk samples were collected weekly and fat, protein, lactose, somatic cell count (SCC), plasmin and plasminogen-derived activity were determined. Activated neutrophils isolated from cows that received supplemental vitamin E had higher (P<0.01) total and membrane-bound u-PA activities during the first 3 weeks after parturition and higher (P<0.01) superoxide production during week 1 prepartum and week 1 post partum compared with the corresponding values of activated neutrophils isolated from control cows. Vitamin E supplementation had no effect (P=0.28) on plasminogen-derived activity in milk. Milk obtained from cows that received supplemental vitamin E had SCC lower by 25% (P<0.05) and plasmin lower by 30% (P<0.01) than corresponding values in milk obtained from control cows. The reduction in plasmin as a result of vitamin E supplementation is very beneficial to the dairy industry because plasmin reduces the cheese-yielding capacity of milk, affects the coagulating properties of milk and its overall ability to withstand processing during cheesemaking. In conclusion, vitamin E supplementation had positive effects on the function of bovine neutrophils and milk quality in a commercial dairy herd.

The effect of various vitamin E derivatives on the urokinase-plasminogen activator system of ovine macrophages and neutrophils

The effect of vitamin E derivatives on the urokinase-plasminogen activator (u-PA) system of resting and phorbol myristate acetate (PMA)-activated ovine macrophages and neutrophils were investigated. Blood monocyte-macrophages and neutrophils were isolated from twenty-four animals. Macrophages or neutrophils were cultured in vitro for 3 or 24 h with or without various vitamin E derivatives: free alpha-tocopherol (alpha-T), alpha-tocopheryl acetate (alpha-TA), or alpha-tocopheryl succinate (alpha-TS). Following incubation, cells were stimulated with 80 microm-PMA. Total cell-associated u-PA, membrane-bound u-PA and free u-PA binding sites were determined before and after stimulation with PMA. Results showed that none of the vitamin E derivatives had any effect (P>0.05) on the u-PA system of resting monocyte-macrophages or neutrophils. In contrast, alpha-TS, but not alpha-TA or alpha-T, increased (P<0.01) total cell-associated u-PA and membrane-bound u-PA of PMA-stimulated macrophages and neutrophils. alpha-TS had no effect (P>0.05) on total u-PA and membrane-bound u-PA activities of macrophages and neutrophils cultured in the presence of 4-phorbol 12,13 didecanoate, a phorbol ester that does not activate protein kinase (PK) C. Addition of H7 (1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride), which is a potent inhibitor of both PK A and C, completely abolished the effect of alpha-TS on total cell-associated u-PA and membrane-bound u-PA of PMA-activated macrophages and neutrophils. Addition of HA1004 (N-(2-quanidinoethyl)-5-isoquinoline sulfonamide hydrochloride), which is a potent PK A but a weak PK C inhibitor, had no effect (P>0.05) on total cell-associated u-PA and membrane-bound u-PA of PMA-activated macrophages and neutrophils cultured in the presence of alpha-TS. Thus, PK C modulates the effect of alpha-TS on the u-PA system of ovine macrophages and neutrophils.

Effects of caponisation on lipid and fatty acid composition of intramuscular and abdominal fat of medium-growth broilers

1. Capons and intact male broilers were used to investigate the effects of caponisation on intramuscular fat and abdominal adipose tissue lipid content and fatty acid profile. 2. Capons had significantly higher total lipid content (P < 0·05). 3. Neutral lipids were the major fractions in intramuscular and abdominal fat but their proportions differed significantly among groups and tissues (P < 0·05). 4. The predominant saturated, monounsaturated and polyunsaturated fatty acids in all samples were C16:0, C16:1 ω-9, C18:0, C18:1 ω-9, C18:1 ω-7, C18:2 ω-6 and C20:4 ω-6. 5. Caponisation resulted in a significant ω-6/ω-3, PUFA and PUFA/SFA ratio reduction as well as a significant increase in atherogenic and thrombogenic indices increase in intramuscular fat (P < 0·05) without affecting their appropriate value for a healthy diet.

Effects of caponization on growth performance, carcass composition and meat quality of males of a layer line

The present experiment was conducted in order to evaluate the effects of caponization on growth, carcass composition and meat quality of males of a layer line reared until the 34th week of age. Two hundred and fifty males of a layer line were purchased and randomly divided in two equal groups: intact males and capons. Caponization was conducted at 45 days of age. Three slaughters were performed at the ages of 26, 30 and 34 weeks of age. Caponization did not affect feed intake and final live weight. Capons had a heavier breast and lighter leg than intact males. Lipid accumulation was enhanced by the caponization and fat was stored mainly at the fat pad and the skin of the commercial parts excluding the drumstick. The Pectoralis major muscle of capons had higher intramuscular fat content, lightness (L) and yellowness (b*) values and lower redness values (a*). In conclusion, caponization could be applied to a layer genotype in order to produce commercial chicken meat.

Cellularity and enzymatic activity of adipose tissue in the Karagouniko dairy breed of sheep from birth to maturity

SUMMARY The cellular and enzymatic characteristics of dissected subcutaneous and perirenal adipose tissues were examined in a total of 102 male and female animals from commerical flocks of the Karagouniko dairy sheep. The animals were slaughtered in groups of three males and three females at 45-day intervals from birth to 720 days of age. The following determinations were made on each animal: (1) subcutaneous and perirenal chemical fat, (2) fat cell size and number and (3) the activities of NADP-isocitrate dehydrogenase and 6-phosphogluconate dehydrogenase in subcutaneous and perirenal adipose tissues. Subcutaneous adipose tissue expanded by a combination of fat cell hypertrophy and hyperplasia during the accelerating phase of the growth curve of chemical fat, after which the fat expansion was accomplished primarily by hyperplasia. The changes in perirenal chemical fat weight with increasing age were primarily due to hypertrophy of fat cells during the accelerating phase of the curve of chemical fat growth and due to a combination of hypertrophy and hyperplasia during the diminishing phase of the curve. The enzyme activities were higher in subcutaneous than in perirenal adipose tissue, with the NADP-isocitrate dehydrogenase being the most active enzyme in both tissues and sexes. The changes in enzyme activities in subcutaneous adipose tissue with increasing age were parallel to the changes in the rate of chemical fat weight during growth. ZUSAMMENFASSUNG: Zellularitaet und enzymatische Aktivitaet des Fettgewebes beim Karagouniko Milchschaf von der Geburt bis zur Reife. Es wurden die Anzahl und die Groesse der Fettzellen sowie die Aktivitaeten der NADP-Isocitrat-Dehydrogenase und der 6-Phosphogluconat Dehydrogenase in subcutanen und perirenalen Fettgewebe des Schafes waehrend des Wachstums undersucht. Das Tiermaterial bestand aus 51 maennlichen und 51 weiblichen Schafen der Karogouniko Milchrasse. Die Schafe wurden in Gruppen bestehend aus 3 maennlichen und 3 weiblichen Tieren in 45-taegigen Abstaenden von der Geburt bis zum Alter von 720 Tagen geschlachtet. Es wurden die folgenden Merkmale erfasst: Chemisches Fett, Anzahl and Groesse der Fettzellen, Aktivitaeten der gennanten Enzyme. Das subcutane Fettgewebe wuchs durch eine Kombination von Hypertrophie und Hyperplasia waehrend der beschleunigten Phase der Wachstumskurve fuer das chemische Fett. Nach dieser Wachstumsphase, das weitere Wachstum des subcutanen Fettgewebes kam vorwiegend durch Hyperplasia der Fettzellen zustande. Das perirenale Fettgewebe wuchs zunaechst durch Hypertrophie der Fettzellen und anschliessend durch eine Kombinationn von Hypertrophie und Hyperplasia. Die Aktivitaet der NADP-Isocitrat-Dehydrogenase war hoeher als die Aktivitaet der 6-Phosphogluconat-Dehydronase in beiden Geweben und Geschlechtern waehrend der gesamten Versuchsdauer. Die Aenderungen der Enzymaktivitaet waehrend des Wachstums stimmten gut ueberein mit den entsprechenden Aenderungen der taeglichen Wachstumstrate der subcutanen Fettgewebes.

Cloning and functional characterization of the ovine Hormone Sensitive Lipase (HSL) full-length cDNAs: an integrated approach.

Hormone Sensitive Lipase (HSL) is a highly regulated enzyme that mediates lipolysis in adipocytes. HSL enzymatic activity is increased by adrenergic agonists, such as catecholamines and glucagons, which induce cyclic AMP (cAMP) intracellular production, subsequently followed by the activation of Protein Kinase A (PKA) and its downstream signalling cascade reactions. Since HSL constitutes the key enzyme in the regulation of lipid stores and the only enzyme being subjected to hormonal regulation [in terms of the recently identified Adipose Triglyceride Lipase (ATGL)], the ovine Hormone Sensitive Lipase (ovHSL) full-length cDNA clones were isolated, using a Polymerase Chain Reaction-based (PCR) strategy. The two isolated isoforms ovHSL-A and ovHSL-B contain two highly homologous Open Reading Frame (ORF) regions of 2.089 Kb and 2.086 Kb, respectively, the latter having been missed the 688th triplet coding for glutamine (DeltaQ(688)). The putative 695 and 694 amino acid respective sequences bear strong homologies with other HSL protein family members. Southern blotting analysis revealed that HSL is represented as a single copy gene in the ovine genome, while Reverse Transcription-PCR (RT-PCR) approaches unambiguously dictated its variable transcriptional expression profile in the different tissues examined. Interestingly, as undoubtedly corroborated by both RT-PCR and Western blotting analysis, ovHSL gene expression is notably enhanced in the adipose tissue during the fasting period, when lipolysis is highly increased in ruminant species. Based on the crystal structure of an Archaeoglobus fulgidus enzyme, a three-dimensional (3D) molecular model of the ovHSL putative catalytic domain was constructed, thus providing an inchoative insight into understanding the enzymatic activity and functional regulation mechanisms of the ruminant HSL gene product(s).

Effects of Gestational Maternal Undernutrition on Growth, Carcass Composition and Meat Quality of Rabbit Offspring

An experiment was conducted in order to evaluate the effects of gestational undernutrition of rabbit does on growth, carcass composition and meat quality of the offsprings. Thirty primiparous non lactating rabbit does were artificially inseminated and randomly divided in three treatment groups: Control (C; fed to 100% of maintenance requirements throughout gestation, n = 10), early undernourished (EU; fed to 50% of maintenance requirements during days 7–19 of gestation, n = 10) and late undernourished (LU; fed to 50% of maintenance requirements during days 20-27 of gestation, n = 10). During the 4th week of the gestation period, LU does significantly lost weight compared to C and EU groups (P<0.05). At kindling, C does produced litters with higher proportions of stillborn kits (P<0.05) while the total litter size (alive and stillborn kits) was not different among groups (10.7, 12.8 and 12.7 kits in C, EU and LU groups, respectively). Kit birth weight tended to be lower in the LU group. During fattening, body weight and feed intake were not different among offsprings of the three experimental groups. Moreover, the maternal undernutrition did not have any impact on carcass composition of the offsprings in terms of carcass parts and internal organs weights as well as meat quality of L. lumborum muscle (pH24, colour, water holding capacity and shear values) at slaughter (70 days of age). Therefore, it can be concluded that the gestational undernutrition of the mother does not have detrimental effects on the productive and quality traits of the offsprings.

Effects of caponization on fat metabolism–related biochemical characteristics of broilers

A two-trial experiment was conducted to evaluate the effects of caponization on fat metabolism-related biochemical characteristics of broilers. Male Redbro broilers were purchased, caponized at 3 weeks and reared until either the 18th (Trial 1) or the 24th (Trial 2) week. In Trial 1, five slaughters were performed at 6, 9, 12, 15 and 18 weeks of age while in Trial 2 one slaughter at the end of the experiment (24 weeks). In each slaughter, the abdominal adipose tissue cellularity, the NADP dehydrogenase activity in the liver and some serum lipoproteins concentrations were assessed. Caponization had a marked effect on the adipocyte volume and NADP-malate dehydrogenase activity in the liver at 24 weeks but it did not affect adipocyte number or the activity of NADP-isocitrate dehydrogenase activity at any age (p < 0.05). Regarding the lipoproteins, cholesterol and HDL-cholesterol were elevated in capon serum at 18 weeks of age while no difference was detected in the triglyceride concentration at any age. In conclusion, a relationship between fat deposition at the phenotypic level and the level of lipogenic enzymes and lipoproteins capons was established but not as pronounced as expected as some parameters displayed a constant increasing pattern while others did not.

Expression of plasminogen activator-related genes in the adipose tissue of lactating dairy sheep in the early post-weaning period

There is growing evidence that plasminogen activator inhibitor type 1 (PAI-1) is expressed in adipose tissue and its expression is implicated in inflammation that accompanies obesity-associated diseases. The physiological role of other genes implicated in the plasminogen-activating cascade such as urokinase-type plasminogen activator (u-PA), u-PA receptor (u-PAR) and plasminogen activator inhibitor type 2 (PAI-2) in ovine adipose tissue remains unknown. The objective of this study was to examine the changes in the expression of four plasminogen activator (PA)-related genes during the early post-weaning period in dairy ewes. A total of 21 subcutaneous adipose tissue samples were obtained from seven lactating dairy ewes of the Chios breed at weeks 1, 2 and 4 after weaning. Results indicated that expression of all PA-related genes was detected in most of the samples examined. Greatest expression of u-PAR corresponded to highest (week 1), while greatest expression of PAI-2 corresponded to lowest (week 4) rate of lipolysis, as indicated by the expression of hormone-sensitive lipase, in the ovine adipose tissue. There were no significant differences in the expression of the other two PA-related genes (u-PA, PAI-1) throughout the experimental period. Plasminogen activator-related genes are not expressed in a coordinated manner in the adipose tissue of lactating dairy sheep in the early post-weaning period. In conclusion, adipose tissue mobilization is correlated with highest expression of u-PAR and lowest expression of PAI-2.

Molecular study of ovine glucose 6-phosphate dehydrogenase gene expression in respect to different energy intake

Glucose 6-phosphate dehydrogenase (G6PD) plays an important role in a ruminants metabolism catalyzing the first committed reaction in the pentose phosphate pathway as it provides necessary compounds of NADPH for the synthesis of fatty acids. The cloning of ovine (Ovis aries) G6PD gene revealed the presence of two cDNA transcripts (oG6PD(A) and oG6PD(B)), with oG6PD(B) being a product of alternative splicing and with no similarity to any other previously reported G6PD transcript. Here, we attempt to study the effect of energy balance in ovine G6PD transcript expression, trying simultaneously to find out any potential physiological role of the oG6PD(B) transcript. Changes of energy balance that lead to synergistic changes in the expression of both transcripts, but in opposite directions and not in a proportional way. Negative energy balance favours the presence of the oG6PD(B) transcript leading to a significant increase of its expression, compared to oG6PD(A) expression (P<0.05). In contrast, positive energy balance leads to a significant increase of oG6PD(A) compared to oG6PD(B) expression (P<0.05). In either condition oG6PD(B) expression is unchanged. Regression analysis showed that there is an energy balance threshold where the expression of both transcripts shows no change.