Effects of additive iron on growth,tissue distribution,haematology and immunology of gilthead sea bream, <Emphasis Type="Italic">Sparus aurata</Emphasis>

The comparative effects of iron-supplemented levels on growth, tissue distribution, haematology and immunology of gilthead sea bream, Sparus aurata (2 g) were investigated, using four organic (50, 100, 200, 300 mg ORG/kg diet) and one inorganic iron source (200 INOR mg/kg diet). Fish were treated for 12 weeks with the experimental diets and maintained at a water temperature of 19–22°C. Growth (final weight and specific growth rate), tissue distribution (spleen, liver and muscle), haematological parameters (red blood cells, haematocrit, haemoglobin and mean corpuscular haemoglobin concentration) and non-specific immune indexes (respiratory burst activity and antibacterial activity of serum) were analysed. No significant differences were found in growth and iron tissue distribution among the tested groups. Red blood cell counting was statistically higher in fish given 50 ORG, 100 ORG, 200 ORG and 200 INOR feeds. However, haematocrit, haemoglobin and mean corpuscular haemoglobin concentration were not significantly affected by increasing dietary iron. Fish receiving the 100 ORG diet had the best performance with respect to the respiratory burst activity and significantly higher values for antibacterial activity of serum were obtained in fish fed with the 300 ORG diet. The present findings provided no clear evidence of the optimum iron concentration. However, there was adequate indication that iron supplementation enhanced the performance of gilthead sea bream, mainly from a haematological and immunological point of view.     

Efficient synthesis of (+/-)-4-methyloctanoic acid, aggregation pheromone of rhinoceros beetles of the genus Oryctes (Coleoptera: Dynastidae, Scarabaeidae)

(+/-)-4-Methyloctanoic acid and its ethyl ester are aggregation pheromones of many rhinoceros beetles of the genus Oryctes and are investigated for the control of these pests by olfactory trapping. A simple, economical, and high-yield (>50%) synthesis of (+/-)-4-methyloctanoic acid and its ethyl ester is presented starting from n-hexanal. The key step in this sequence is an orthoester Claisen rearrangement for the elongation of the carbon chain by two.     

Antioxidant activity of dietary oregano essential oil and alpha-tocopheryl acetate supplementation in long-term frozen stored turkey meat

The effects of dietary oregano essential oil and alpha-tocopheryl acetate supplementation on the oxidative stability of long-term frozen stored turkey meat were investigated. Thirty 12-week-old turkeys, randomly divided into five groups, were given a basal diet or a basal diet supplemented with 200 mg of alpha-tocopheryl acetate kg(-1), or 100 or 200 mg of oregano oil kg(-1), or 100 mg of oregano oil plus 100 mg of alpha-tocopheryl acetate kg(-1) for 4 weeks prior to slaughter. Lipid oxidation in breast and thigh meat was assessed after 1, 3, 6, and 9 months of frozen storage at -20 degrees C prior to or following 7 days of refrigerated storage at 4 degrees C. Results showed that oregano oil increased the oxidative stability of breast and thigh meat during the frozen storage. Dietary oregano oil at the inclusion level of 200 mg kg(-1) feed was significantly (p < 0.05) more effective in delaying lipid oxidation compared to the level of 100 mg kg(-1), but equivalent to dietary alpha-tocopheryl acetate supplementation at 200 mg kg(-1), which in turn was inferior to dietary supplementation of 100 mg kg(-1) oregano essential oil plus 100 mg kg(-1) alpha-tocopheryl acetate that was significantly (p < 0.05) superior to all other treatments. Thigh meat was more susceptible to oxidation than breast meat, although the former contained alpha-tocopherol at markedly higher levels. Mean alpha-tocopherol levels in breast and thigh meat from all treatments decreased during the frozen storage, the decrease being sharper between 1 and 3 months of frozen storage for breast and between 3 and 6 months for thigh meat. Oregano oil supplementation increased (p < 0.05) the retention of alpha-tocopherol in meat, the increase being positively correlated with the supplementation level. However, the retention of alpha-tocopherol in meat could only partly elucidate the antioxidant activity exhibited by dietary oregano oil supplementation.     

Monitoring the gravitational reflex of the ectoparasitic mite Varroa destructor: A novel bioassay for assessing toxic effects of acaricides

We investigated the effect of several acaricides on Varroa destructor by monitoring the rhythmic expansion of the sternum, followed by a strong flexion of the legs, initiated when the mite was placed in a dorsal side-down position, as an indication of a mite’s vitality. The pulses generated by the force of the rhythmic expansions had an average duration of 3.11 s, force (amplitude) of 73 μN, and frequency of 0.228 Hz. These parameters remained constant for the first 10 h of recording, whilst significant changes occurred after 15 h. The rhythmic sternal expansion is an indication of a Varroa mite’s gravitational reflex, or attempt to return to an upright position; this reflex is observed in all invertebrates and vertebrates. The sternal expansion can be recorded for over 20 h, or for as long as the Varroa mite remains alive, and the expansion stops as soon as the mite is placed in a normal, upright position. Proper function of the chain of proprioceptors, interneurons, motorneurons, neuromuscular junctions, and muscles of Varroa is required for the initiation and maintenance of such a behavioural motor pattern. Any deleterious effect of synthetic chemicals or natural compounds (acaricides) may have a direct effect on one or more of these links, thereby disturbing or even inhibiting the reflex. Topical application of 1.81 × 10⁻³ mg/mite of amitraz completely inhibited the gravitational reflex within 60–70 min for all mites tested. The volatile acaricides formic acid (13.83 mg), thymol crystals (250 mg), and Apiguard® (1000 mg) eliminated the reflex within 10–35 min. This bioassay, based on the gravitational reflex, could be a useful tool for accurate assessment of the acaricidal action of numerous compounds under laboratory conditions, saving money and time necessary to conduct field trials.     

Linking small pelagic fish and cetacean distribution to model suitable habitat for coastal dolphin species,Delphinus delphis and Tursiops truncatus,in the Greek Seas (Eastern Mediterranean)

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Effects of long-term feed deprivation on body weight loss,muscle composition,plasma metabolites,and intermediate metabolism of meagre (<Emphasis Type="Italic">Argyrosomus regius</Emphasis>) under different water temperatures

The effect of feed deprivation at four water temperatures (17, 20, 23, 26 °C) was investigated in meagre (Argyrosomus regius) of initial mean weight ± SD, 116.16?±?4.74 g, in triplicate groups. Fish were deprived of feed for a period of 60 days and sampled on days 0, 14, 41, and 60, during which body weight, specific growth rate, somatic indices, muscle proximate composition, plasma metabolite levels (total lipids, proteins, cholesterol, triglycerides, glucose), and liver and muscle enzymatic activities [L-lactate dehydrogenase (L-LDH), citrate synthase (CS), malate dehydrogenase (MDH)] were evaluated. Long-term feed deprivation resulted in a significant decrease in body weight, condition factor (CF), hepatosomatic index (HSI), muscle lipids, and plasma metabolites (all except proteins) and increase in muscle moisture. Plasma glucose concentration decreased with time and became significantly lower at 41 and 60 days. Glucose concentration and weight loss expressed a different response in the short term (14 days) than in the long term (14 and 60 days) of feed deprivation, suggesting a change in glucose metabolic profile. After 60 days of feed deprivation, there was an increase in the L-LDH activity in the liver at all temperature levels, which reflects a rising glycolytic potential by activating the carbohydrate metabolism and an ATP-dependent demand. MDH activity increased in the liver and muscle, except at 17 °C in the muscle, which indicates aerobic glycolysis and lipolysis. CS activity in the liver increased after the 60 days, whereas that in the muscle decreased, indicating the muscle is less dependent on aerobic oxidation for energy reserves.     

Cultivar and seasonal effects on the contribution of pre-anthesis assimilates to safflower yield

In crops grown under Mediterranean environments, translocation of pre-anthesis assimilates to the seed is of great importance for seed growth, because hot and dry conditions during the seed filling period diminish photosynthesis and crop nitrogen uptake. This field study was conducted to assess the genetic and seasonal variation in the amount of pre-anthesis dry matter and nitrogen accumulated and translocated to seed by safflower (Carthamus tinctorius L.) plants, and the possible N losses occurring between anthesis and maturity. Ten genotypes, 4 hybrids and 6 open pollinated cultivars, were grown for 2 growing seasons without irrigation, on a silty clay (Typic Xerorthent) soil. The proportion of dry matter and N content at anthesis that was translocated to seed differed among genotypes and ranged from 14.9 to 39.6 and from 24.8–59.3%, respectively. Genotypic differences in dry matter and N translocation were mainly associated with dry matter and N accumulated during the vegetative growth of the plants. Greater amounts of dry matter and N content at anthesis resulted in a greater dry matter and N translocation to seed during the filling period. When the N contents of aboveground plant parts at anthesis and maturity were compared, both gains and losses were observed, and were mainly related to the sink size. No N losses were detected when yield was high. When yield was low, N losses depended on N content at anthesis; high N content resulted in N losses, otherwise no N losses were observed. The contribution of pre-anthesis accumulated reserves to seed weight ranged from 64.7 to 92.2%, indicating the importance of pre-anthesis storage of assimilates for attaining high safflower yield.     

Nitrogen utilization efficiency of safflower hybrids and open-pollinated varieties under Mediterranean conditions

The identification of the factors determining nutrient utilization of safflower (Carthamus tinctorius L.) is useful for the successful introduction of the crop to the cropping system of a region. A field study was conducted to compare and analyze the relative importance of the various component traits causing variation in nitrogen utilization efficiency (NUE) of safflower under Mediterranean conditions. Ten genotypes, four hybrids and six open-pollinated varieties, were grown for two growing seasons without irrigation, on a silty clay (Typic Xerorthent) soil. Seed yield varied greatly among genotypes and ranged from 923 to 3391 kg ha⁻¹. Hybrids showed a mean seed yield superiority of 12.5% against varieties. Seed yield was the most important component of seed N yield and its contribution to the total variation in seed N yield among genotypes was at least 53%. NUE for biomass production during the seed-filling period was lower compared to that during the vegetative period. Genotypes differed in NUE for seed production (NUE_s) and the differences followed those of nitrogen harvest index (NHI). The contribution of NHI to the total variation in NUE_s among genotypes was much greater compared to that of yield per unit seed nitrogen and accounted for more than 79%. NUE_s is positively correlated with seed yield, suggesting that high yield was probably associated with more efficient exploitation of nitrogen. NUE_s is negatively correlated with (leaf + stem) N concentration at maturity, meaning that low straw N concentration may be indication of higher NUE_s. Results indicated that selection for NUE in safflower should be based on multiple criteria rather than just one criterion and also should be accompanied by evaluation for seed yield to ensure an improvement in both traits.     

Blood gas and acid-base status during tiletamine/zolazepam anaesthesia in dogs

OBJECTIVE: To evaluate the effect of the tiletamine/zolazepam (TZ) combination (Zoletil 100; Virbac, Carros, France) with and without atropine on blood gas values and acid-base status in dogs. STUDY DESIGN: Randomized cross-over experimental study. ANIMALS: Six healthy adult cross-bred dogs, weighing 11.0-18.5 kg. MATERIALS AND METHODS: Each dog received four different drug treatments at intervals of at least 15 days: (i) 5 mg kg(-1) intravenous (IV) TZ (TZ.IV); (ii) 10 mg kg(-1) intramuscular (IM) TZ (TZ.IM); (iii) atropine, 20 microg kg(-1) IV, followed 5 minutes later by 5 mg kg(-1) TZ IV (A.TZ.IV); and (IV) atropine (same dose) given 5 minutes before 10 mg kg(-1) TZ IM (A.TZ.IM). Arterial blood samples were collected from each dog before drug administration (baseline) at induction of anaesthesia (time 0) and 2, 5, 10 and 30 minutes thereafter. RESULTS: Transient hypoxaemia and respiratory acidosis were observed just after induction. PaO(2) and SaO(2) dropped, while H(+) concentration and PaCO(2) rose significantly above baseline values. In groups TZ.IV and A.TZ.IV, PaO(2) values as low as 6.0-6.4 kPa (45-48 mm Hg) were recorded. However, there was no significant difference in blood gas variables among the groups encountered during the evaluation period. The overall change in [HCO(3) (-)] and base excess (BE) was not significant among groups. Atropine did not affect the above variables. CONCLUSIONS AND CLINICAL RELEVANCE: Tiletamine/zolazepam injection may induce transient hypoxaemia and respiratory acidosis, but acid-base status changes are clinically unimportant. Particularly, close observation of dogs is recommended during the first 5-10 minutes after induction with TZ, especially in animals with cardiopulmonary disease. TZ should perhaps not be used in animals intolerant of tachycardia.