The combined effects of temperature and GnRHa treatment on the final stages of sexual maturation in Atlantic salmon (Salmo salar L.) females

Atlantic salmon (Salmo salar L.) females (2 SW), maturing for the first time, were reared under one of three temperature regimes (high: 14.3 ± 0.5°C; natural: 10.6 ± 1.0°C; and cold: 6.9 ± 1.0°C) in combination with one of two experimental treatments; an injection of GnRH analogue (GnRHa) contained in biodegradable microspheres, or a sham injection (microspheres only). The six experimental groups were then reared under simulated natural photoperiod for 4 weeks. Blood samples were drawn for analysis of plasma steroid levels and the fish were inspected for ovulation weekly. Batches of stripped eggs were incubated in triplicate incubators in raceways until the eyed stage. Treatment with GnRHa resulted in a substantial advancement and synchronization of ovulation at all temperatures, while exposure to cold water also appeared to advance ovulation slightly. While 75% (warm and cold) to 90% (natural) of GnRHa fish ovulated during the 4-week trial, only 30% of sham-treated females exposed to cold water, and none of the sham-treated fish held at higher temperatures, ovulated during this period. Survival rates of embryos to the eyed-stage were significantly higher for broodstock exposed to cold water. Plasma levels of testosterone (T), 17β-oestradiol (E₂), and 17α,20β-dihydroxy-4-pregnen-3-one (17,20βP) were all significantly affected by treatment with GnRHa and, to a lesser extent, temperature. The efficiency of GnRHa in counteracting the negative effects of high temperature on ovulation and the associated changes in circulating sex steroids suggest that temperature inhibition operates at least in part at the brain or pituitary.     

Nutritive and antioxidative potential of fresh and stored pomegranate industrial byproduct as a novel beef cattle feed

Pomegranate peel is a nutritive-rich byproduct whose amounts are extensively growing due to the exponential increase in the production of pomegranate juice and "ready to eat" arils. Pomegranate peel is a rich source for antioxidants and thus may serve in the prevention of cattle diseases and in the improvement of beef products, making it an attractive component in beef cattle diets. The present study aims to evaluate the effect of commonly used storage practices on the nutritive and antioxidative properties of pomegranate peel. In general, storage conditions preserved most antioxidant capacity. Ensiling ambivalently affected the nutritive values of the peel and promoted increased levels of antioxidative components. In addition to polyphenols, nonphenolic components, such as alpha- and gamma-tocopherols, contributed to the total antioxidative capacity, and several minerals found in the peel added to its nutritional value. Dietary supplementation with fresh peels promoted significant increases in feed intake and alpha-tocopherol concentration in the plasma, with positive tendency toward increased weight gain of bull calves. All in all, the nutritive value and the antioxidant capacity of pomegranate peel turn it into a favorable health-promoting constituent of feedlot beef cattle diet.     

The bioactivity of gonadotropin releasing hormones and its regulation in the gilthead seabream,Sparus aurata: in vivo andin vitro studies

Thein vivo andin vitro potency of native and modified forms of gonadotropin releasing hormone (GnRH) to release gonadotropin (GtH) was studied inSparus aurata and correlated with their relative susceptibility to degradation by cytosolic-bound enzymes of the pituitary, kidney, and liver. Salmon (s) GnRH and luteinizing hormone-releasing hormone (LHRH) are equipotent whereas analogs of these peptides ((D-Arg⁶-Pro⁹NET)-sGnRH, (D-Ala⁶-Pro⁹NET)-LHRH, (D-Trp⁶)-LHRH) are superactive in inducingin vivo GtH release (at 10 μg/kg body weight). In anin vitro superfusion system of pituitary fragments all analogs are equipotent to the native peptides (at 10⁻¹⁰ to 2.5 × 10⁻⁷M). sGnRH and LHRH are rapidly degraded by cytosolic peptidases of the pituitary, liver, and kidney. The preferred site of cleavage is the Tyr⁵-Gly⁶ bond. Substitution of the position 6 glycine by D-amino acids renders the 5–6 bond resistant to degradation and shifts the main site of cleavage to the Pro⁹-Gly¹⁰NH₂ bond. Substitution at position 6 (as above) and at position 10 with Pro⁹NET results in analogs that are resistant to degradation. We propose that enzymatic cleavage terminates GnRH bioactivityin vivo and thus increased resistance to degradation is a major determinant of GnRH analog superactivity.     

Resveratrol and a novel tyrosinase in Carignan grape juice

Polyphenol levels in wines are affected by the wine-making process. Resveratrol is one polyphenol which has been the subject of a commendable amount of recent research. In this work, we found that resveratrol is immediately degraded by tyrosinase. A novel tyrosinase was purified from Carignan grapes. The purification process included salting out and separation on a cation-exchange column, followed by gel filtration. Tyrosinase was purified in a homogeneous form by SDS-PAGE and was characterized: its specific activity toward 3-(3,4-dihydroxyphenyl)-L-alanine (DOPA) increased by a factor of 24 with an overall recovery of 3% of initial activity. The apparent molecular mass of the purified tyrosinase was 40 kDa as determined by SDS-PAGE, and 42 kDa as determined by gel filtration. Its activity was optimal at pH 6 and at 25 degrees C. The enzyme exhibited high activity toward phenylenediamine, epicatechin, pyrogallol, DOPA, and resveratrol. Tyrosinase activity was inhibited by KCN, thiourea, and SO(2). Resveratrol levels were stable following the removal of proteins from the juice, suggesting that early spraying of grapes with SO(2) is an important factor affecting the final amount of resveratrol in wine.     

Influence of time of harvest and maturity index on olive oil yield and quality

Harvesting plays a major role in the virgin olive oil production line, being the most expensive single component, but also due to its significant effect on the whole year's produce. Previous studies have focused on the effects of harvest timing on either oil yield or quality. Here we determined the separate and combined effects of harvesting date, fruit maturation, cultivar and fruit load on olive oil quality and quantity. Cultivars typical to the Middle East region were selected: the traditional cv. Souri and the newer cv. Barnea, grown under intensive conditions. The results demonstrate fundamental differences between the two cultivars with respect to harvest strategy. In high-yielding ‘Barnea’, oil accumulation continued throughout the ripening season resulting in increasing yield of oil with time while maintaining high quality. Hence, exploiting the production potential in ‘Barnea’ requires late harvest and advanced fruit maturity. However, in heavily loaded ‘Souri’, oil accumulation was accompanied by early massive shedding of fruits. Furthermore, late harvest and advanced maturation in ‘Souri’ were associated with a sharp increase in free fatty acids combined with a rapid decline in polyphenol content, and in MUFA to PUFA and saturated to unsaturated fatty acid ratios, all resulting in loss of oil quality. Rapid decline in oil yield coupled with deterioration of oil quality call for early harvesting at low maturity index in ‘Souri’. In medium-yielding trees of both cultivars, maturation progressed more rapidly, resulting in earlier harvest to utilize optimal oil potential.     

A serosurvey of Hepatozoon canis and Ehrlichia canis antibodies in wild red foxes (Vulpes vulpes) from Israel

A seroepidemiological survey was conducted to investigate the prevalence of antibodies reactive with Ehrlichia canis and Hepatozoon canis antigens in free-ranging red foxes (Vulpes vulpes) in Israel. Of 84 fox sera assayed, 36% were seropositive for E. canis by the indirect fluorescent antibody (IFA) test and 24% were positive for H. canis using an enzyme-linked immunosrbent assay (ELISA). Canine ehrlichiosis and hepatozoonosis appear to be endemic in the wild red fox populations in Israel, and foxes may serve as a reservoir for infection of domestic dogs and other wild canine species.     

Protection of lipids from oxidation by epicatechin, trans-resveratrol, and gallic and caffeic acids in intestinal model systems

Consumption of polyphenols is associated with health promotion through diet, although many are poorly absorbed in animals and humans alike. Lipid peroxides may reach the intestine and initiate deleterious oxidation. Here we measured inhibition of the oxidation of linoleic acid (LA) in authentic fluid from rat small intestine (RIF) by two dietary polyphenols, a flavonoid, epicatechin (EC), and a stilbene, resveratrol (RV), and by gallic (GA) and caffeic (CA) acids, and their partition coefficients. Both polyphenols inhibited 80%, and CA inhibited 65%, of the production of hexanal. GA was the weakest antioxidant in this assay. Interestingly, measuring peroxides production in RIF showed that only epicatechin inhibited the first stage of oxidation. The oxidizing agent, the antioxidant comound, the solution pH and lipophilicity are known to affect the total antioxidative activity. We suggest that the mechanism of this activity changes in accord with the environment: i.e., RV may act as a free radial scavenger, but here, in protecting lipids in intestinal fluid from oxidation, it acts as a hydrogen atom donor. Since the concentration of phenolics is much higher in the intestinal fluid than is ever achieved in plasma or other body tissues, it is suggested that their antioxidant activity could be exerted in the gastrointestinal tract (GIT), breaking the propagation of lipid peroxides oxidation and production of toxic compounds.     

The N-acetyl-D-glucosamine specific adhesin from Mannheimia haemolytica activates bovine neutrophils oxidative burst

In this work we identified specific bovine leukocytes that were bound by the Mannheimia haemolytica adhesin molecule (MhA) and the biological effect on the leukocytes. Histochemical staining and flow cytometry showed that MhA bind neutrophils (90%) and monocytes (5%). MhA induced an oxidative response in purified neutrophils; this effect was 1.5-fold higher than the effect observed with control cells activated with Zymosan. Cellular binding by MhA was inhibited with GlcNAc and its oligomers, as well as by glycoproteins containing tri- and tetra-antennary N-glycosydically linked glycans. MhA-induced oxidative burst was significantly inhibited by GlcNAc, iodoacetamide, superoxide dismutase, and piroxicam (p<0.05). Our findings suggest that among bovine leukocytes, neutrophils are the main target for MhA, inducing production of oxidative radicals by non-opsonic mechanism that seem to play an important role in tissue damage during mannheimiosis.     

Antioxidant activity and inhibition of alpha-glucosidase by trans-resveratrol, piceid, and a novel trans-stilbene from the roots of Israeli Rumex bucephalophorus L

The roots of Rumex bucephalophorus, collected in Israel, were analyzed for trans-stilbenes. Two stilbene-O-glycosyl derivatives were identified, in addition to 3,5,4'-trihydroxystilbene (1) (resveratrol). The stilbene-O-glycosyl derivatives were 5,4'-dihydroxystilbene-3-O-beta-d-glucopyranoside (2) (piceid) and the new 5,4'-dihydroxystilbene-3-O-alpha-arabinopyranoside (3), which is being named rumexoid. The structure of rumexoid was elucidated by using spectroscopic data. The antioxidant capacities of stilbenoids 1-3 were determined and expressed as trolox equivalent antioxidant capacity (TEAC). TEAC value for trans-resveratrol was highest (2.7) and for rumexoid lowest (1.5). In vitro, trans-resveratrol and rumexoid demonstrated a potent inhibitory effect on alpha-glucosidase activity (IC50 < 0.1 and < 0.5 mM, respectively). The commercial antidiabetic agent acarbose was shown to inhibit only 35% of the enzyme activity at 0.5 mM. The addition of piceid to the reaction mixture did not inhibit alpha-glucosidase in vitro in the range of concentrations used. These findings extend the range of reported beneficial effects of stilbene derivatives, and demonstrate the multifaceted activities that dietary polyphenols may exert in the intestine, where their concentrations are highest in the body.     

Effect of NaCl and high pH on seedling growth of 15 Eucalyptus camaldulensis Dehnh. provenances

Eucalyptus camaldulensis Dehnh. is a moderately salt-tolerant Australian tree species widely used in farm forestry, often in salt-affected landscapes. In a glasshouse experiment, E. camaldulensis seedlings from 15 wide-ranging Australian seed sources (provenances), were cultured in sand-filled pots and treated for 57 days with control (no added NaCl in tap water, neutral pH), saline (150 mol m^–3 NaCl, stepped high pH (pH 7.6 to 9.5) and combined NaCl and high pH solutions. Significant differences were found among provenances in height and shoot dry weight. Differences in provenance response to treatment were found for dry weight but not for height. Reductions in shoot dry weight due to NaCl and high pH ranged from 42.9% to 82.0% and 4.3% to 51.7% respectively. Provenances from Lake Hindmarsh-SE (Victoria) and Lake Albacutya-N (Victoria) had relatively high tolerance to both stresses whereas those from Lake Albacutya-S (Victoria), Lowan Valley (Victoria), Silverton (New South Wales) and Katherine (Northern Territory) had low tolerance to both stresses. Provenances from De Grey River and Fitzroy River (Western Australia) were most tolerant of high pH. The performance of these provenances in this experiment generally accorded well with that in saline field environments.