Growth performance and carcass characteristics of broiler chickens fed diets supplemented with graded levels of charcoal from maize cob or seed of <Emphasis Type="Italic">Canarium schweinfurthii</Emphasis> Engl

Growth performances and carcass characteristics of broiler chickens fed diets supplemented with graded levels of Canarium schweinfurthii Engl seed (charcoal A) or maize cob (charcoal B) were studied using a total of 110 3-week-old male chicks. 11 experimental diets including a control and other containing either 0.2, 0.4, 0.6, 0.8 or 1% charcoal from C. schweinfurthii Engl seed (A_0.2, A_0.4, A_0.6, A_0.8, and A_1%, respectively) or from maize cob (B_0.2, B_0.4, B_0.6, B_0.8, and B_1%, respectively) supplements were used. Each of the diets was fed to ten individually birds caged in a completely randomized design. Results indicated that birds fed 0.2, 0.4, and 0.6% of either charcoal A or B had significantly (P < 0.05) higher final body weights as compared to control birds, while, above 0.6% slightly depressed average final body weights and weight gain. The best growth performance was achieved with 0.2% inclusion of charcoals. There was no significant (P > 0.05) influence of charcoal B on the overall feed intake. Only the B_0.6 feed significantly (P < 0.05) improved feed conversion ratio as compared with the control. Dressing percentage, liver weight and abdominal fat were not significantly (P > 0.05) affected by charcoal. However, there was a significant (P < 0.05) reduction in gizzard weight with charcoal B. Charcoal had no significant (P > 0.05) influence on intestine length and weight. More than 0.6% of charcoal A significantly (P < 0.05) depressed intestine density. It was concluded that under the conditions of this study, charcoal from maize cob or Canarium seeds could be used to improve growth performances and some carcass traits in broiler chickens.     

Just Add Water and Salt: the Optimisation of Petrogenic Hydrocarbon Biodegradation in Soils from Semi-arid Barrow Island, Western Australia

We investigated the potential of soil moisture and nutrient amendments to enhance the biodegradation of oil in the soils from an ecologically unique semi-arid island. This was achieved using a series of controlled laboratory incubations where moisture or nutrient levels were experimentally manipulated. Respired CO₂ increased sharply with moisture amendment reflecting the severe moisture limitation of these porous and semi-arid soils. The greatest levels of CO₂ respiration were generally obtained with a soil pore water saturation of 50?C70%. Biodegradation in these nutrient poor soils was also promoted by the moderate addition of a nitrogen fertiliser. Increased biodegradation was greater at the lowest amendment rate (100 mg N kg^?1 soil) than the higher levels (500 or 1,000 mg N kg^?1 soil), suggesting the higher application rates may introduce N toxicity. Addition of phosphorous alone had little effect, but a combined 500 mg N and 200 mg P kg^?1 soil amendment led to a synergistic increase in CO₂ respiration (3.0×), suggesting P can limit the biodegradation of hydrocarbons following exogenous N amendment.     

Modelling diurnal and seasonal patterns of maize pollen emission in relation to meteorological factors

Modelling the risk of cross-pollination between maize crops can help to define efficient isolation methods to reduce the risk of gene flow between these crops. However, the use of such models over the pollen emission season is limited by poor estimations of pollen emission. In this study, we present a model that predicts hourly pollen emission fluxes over the pollen season and that accounts for effects of both meteorological conditions and crop variety. It consists of two sub-models that predict: (i) the seasonal pattern on a daily basis and (ii) the normalized diurnal pattern on an hourly basis.To assess the variability of pollen emission, ten field experiments were carried out in July and August over four years using three crop varieties. The model was built from (i) a parameterisation of the measured diurnal and seasonal patterns of pollen emission followed by (ii) a quantification of the relationships between parameter values and meteorological conditions. Total production of pollen was fairly constant for a given variety over years and sowing dates, while patterns of emission varied with meteorological conditions. The pollen emission season was longer when temperature was low and humidity was high. In most cases, the diurnal pattern was unimodal: the onset and the peak of emission were delayed when relative humidity was high or wind speed was low. In some cases, a second peak of emission occurred during the afternoon. This was observed more frequently when temperatures were high.     

Effect of some repetitive factors on turbot stress response

The stress response of the turbot, Scopthalmus maximus (L.), to repetitive factors including netting, air exposure, blood sampling and hand-stripping, were tested using two different tank sizes as well as two blood sampling techniques. Exposure of juvenile fish to air for 1-4 min had no immediate effect on plasma cortisol concentrations or haematocrit values. Similarly, the serial netting of immature fish from tanks did not significantly modify plasma cortisol concentrations, haematocrit or osmolarity values. Hand-stripping of mature males was more disturbing than air exposure. The cumulative effect on plasma cortisol levels and osmolarity of stress factors such as netting, air exposure, blood sampling and stripping applied simultaneously to mature males in a 16 m3 tank and repeated twice daily for several days was recorded. The level of cortisol increased from 5 ng ml-1 to 300 ng ml-1 after 10 days of treatment, while an osmoregulatory imbalance and fish death were observed. Moreover, adaptation of fish to smaller tanks seemed to improve the increased plasma cortisol levels and death rate. Reduction in the number of stress factors applied greatly decreased both the range of physiological responses and the death rate. In order to avoid a cumulative stress response, handling of fish should therefore be reduced to a minimum.     

Pharmacokinetics and tissue distribution of oxytetracycline in sea bass, Dicentrarchus labrax, at two water temperatures

A pharmacokinetic study of oxytetracycline (OTC) following an intravascular administration (40 mg/kg) was carried out in sea bass, Dicentrarchus labrax (110 g), at 13.5 and 22 °C water temperature. Blood, muscle and liver samples were taken at 1, 2, 4, 8, 16, 32, 64 and 128 h post-injection. The plasma data were conformed to a two-compartment model. The kinetic profile of the drug was found to be temperature dependent. The absorption half-life (t_1/2) of OTC was 0.98 and 0.192 h at 13.5 and 22 °C, respectively, whereas the elimination half-time (t_1/2β) of the drug was 69 h at 13.5 °C and 9.65 h at 22 °C. The apparent volume of distribution of the drug at steady state [V_d(ss)] was 5.62 l/kg at 13.5 °C and 2.59 l/kg at 22 °C. The mean residence time (MRT) of OTC was found to be 37.7 h at 22 °C and 71 h at 13.5 °C. The total clearance of the drug (CL_T) was calculated to be 73.5 and 68.7 ml/kg/h at 13.5 and 22 °C, respectively.

Liver levels indicated higher OTC values than respective muscle levels at all time points and for both temperatures. The elimination of OTC from tissues tested was faster at the high temperature, whereas the drug was eliminated faster from liver compared to muscle when comparisons are made at the same temperature.     

Development of a reference diet for use in indispensable amino acid requirement studies of gilthead seabream Sparus aurata L.

The development of a test diet supporting good fish growth to be used in gilthead seabream indispensable amino acid (IAA) requirement studies based on dose–response relationship was the objective of the present study. Four isonitrogenous diets, one serving as control (diet C) based on fish meal LT, and three others in which the fish meal component was reduced to 45% and the rest of the nitrogen was provided by mixtures of crystalline AA were formulated. Diet S resembled the whole body IAA profile of wild seabream. Diet D was made deficient in all IAA and a 10% excess of IAA compared with diet S was used in diet E. Triplicate groups of fish were fed the diets to satiation for 6 weeks. Growth parameters and nutrient utilization efficiencies among diets C and S were similar, while excessive supplementation of IAA negatively affected most of them, compared with the control. Whole body composition was differentiated in relation to the diet fed. No significant differences were observed among groups fed the control and diet S. As shown by the results, the presence of crystalline AA in diet S does not significantly affect growth, and could therefore serve as control diet in IAA requirement studies of gilthead seabream.     

Temperature-dependent pharmacokinetics and tissue distribution of oxolinic acid in sea bass, Dicentrarchus labrax L., after a single intravascular injection

The pharmacokinetics and tissue distribution of oxolinic acid following an intravascular administration (15 mg kg^?1 fish) were determined in sea bass, Dicentrarchus labrax L. (110 g), at 13 °C and 22 °C water temperature. The kinetic profile of the drug was found to be temperature dependent, with increased temperature having a greater effect on distribution after equilibrium and the elimination phase than on the distribution process. The distibution half‐life of oxolinic acid was 1.15 and 2.76 h at 22 °C and 13 °C respectively, whereas the elimination half‐life of the drug was 55 h at 22 °C and 315 h at 13 °C. The values of the apparent volume of distribution (1.44 L kg^?1 at 22 °C and 3.31 L kg^?1 at 13 °C) and the volume of distribution at steady state (5.2 and 14.7 L kg^?1 at the high and low temperature respectively) were considerably different between the two tested temperatures. The total body clearance of the antibiotic was found to be low (1.47 L kg^?1 day^?1 at 22 °C and 0.80 L kg^?1 day^?1 at 13 °C). Lower rates of elimination were found for the liver compared with muscle, the difference increasing with increasing temperature, while elimination rates from the serum were higher than those of other tissues, especially at the high temperature.