An evaluation of the duration of efficacy of emamectin benzoate in the control of Caligus curtus Müller infestations in Atlantic cod, Gadus morhua L

The duration of efficacy of emamectin benzoate in the control of Caligus curtus infestations in Atlantic cod, Gadus morhua L., was studied following an administration of 50 μg kg^?1 for seven consecutive days. No lice were found on medicated fish when challenged 1 week (challenge 1) or 5 weeks (challenge 2) following termination of medication, whereas the mean abundance of lice among the unmedicated fish was 17.9 and 19.3 lice per fish in challenge 1 and 2, respectively. Muscle concentrations of 19.5 ± 8.2 ng g^?1 and 3.4 ± 0.9 ng g^?1, respectively, and skin concentrations of 23.1 ± 10.8 and 4.2 ± 1.0 ng g^?1, respectively, were found 27 and 55 days following the termination of medication. Tissue concentrations and the duration of efficacy indicate a dosing regime for emamectin in cod, similar to the regime used for Atlantic salmon, Salmo salar L.     

Synthesis of macroporous minerals with highly ordered three-dimensional arrays of spheroidal voids

Titania, zirconia, and alumina samples with periodic three-dimensional arrays of macropores were synthesized from the corresponding metal alkoxides, using latex spheres as templates. In a fast, single-step reaction, the monomeric alkoxide precursors permeate the array of bulk polystyrene spheres and condense in air at room temperature. Close packed, open-pore structures with 320- to 360-nanometer voids are obtained after calcination of the organic component at 575 degreesC. The examples presented demonstrate the compositional diversity possible with this technique. The resulting highly structured ceramics could have applications in areas ranging from quantum electronics to photocatalysis to battery materials.     

Minimally invasive approach to lumbosacral decompression in a cadaveric canine model

AIMS: To determine efficacy of a minimally invasive (MI) surgical approach using a human MI lumbar retractor for canine lumbosacral dorsal laminectomy and partial discectomy and to compare this technique to the standard open surgical (OS) approach.

METHODS: Lumbosacral dorsal laminectomy and partial discectomy was performed on 16 large-breed canine cadavers using either a standard OS (n=8) or MI (n=8) approach. Skin and fascial incision length, procedure time, and intraoperative complications were recorded. Postoperatively specimens were evaluated for laminectomy and discectomy dimensions, and visible damage to the cauda equina and exiting nerve roots.

RESULTS: Median length of skin and fascial incisions in the OS group were longer than in the MI group (p<0.001). Median laminectomy length was similar between both approaches (p=0.234) but width was greater for the MI than OS approach (p=0.002). Both approaches achieved similar partial discectomy width (p=0.279). Overall surgical time was longer for MI approaches compared to OS, with a median of 18.5 (min 15.5, max 21.8) minutes for MI compared to 14.6 (min 13.1, max 16.9) minutes for OS (p=0.001).

CONCLUSIONS: The MI approach reduced incision lengths while retaining comparable laminectomy and discectomy dimensions. For this in vitro model the MI approach required more time to complete, but this difference may not be relevant in clinical cases.

CLINICAL RELEVANCE: Dogs undergoing lumbosacral dorsal laminectomy are commonly large-breed dogs. The traditional open approach requires a large skin incision and soft tissue dissection, especially in overweight animals. A MI approach accomplishing the same surgical result while minimising soft tissue trauma could reduce post-operative pain and recovery time, and may lower wound-related complications. Clinical studies are needed to confirm postoperative benefit and assess operating times in vivo.     

Surveillance of selected nutrients,additives and undesirables in commercial Norwegian fish feeds in the years 2000–2010

This article presents data on commercial, Norwegian fish feeds from 2000 to 2010, including elements, additives, some selected vitamins and a range of environmental contaminants. Iodine, selenium and vitamin D concentrations, all declined during the time period; simultaneously, a reduction in marine ingredients in feeds has occurred. Still, the feeds fulfilled known fish nutrient requirements. Arsenic (As) in the feed was fitted with a polynomial regression with peak concentrations in 2004, correlating with fishery landings of blue whiting (Micromesistus poutassou), a reduction species with high content of As. A polynomial regression was also significant for mercury, which peaked in 2005 and was correlated to fish meal (FM) inclusion in the feeds. Residues of the pesticide DDT and its metabolites, chlordane and toxaphene, as well as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers and sum dioxins and dioxin‐like PCBs, all decreased during this time period. These positive changes in undesirable substances can likely be attributed to the increasing replacement of marine ingredients with plant ingredients, as well as the increased use of South American fish oils rather than North Atlantic ones. On the other hand, cadmium concentrations were twofold higher in South American FMs, and increased in feeds from 2000 to 2010.     

Corpus Luteum Development and Function after Supplementation of Long‐Acting Progesterone During the Early Luteal Phase in Beef Cattle

Strategic supplementation of P4 may be used to increase conception rates in cattle, but timing of supplementation in relation to ovulation, mass of supplementary P4 and formulation of the P4‐containing supplement has not been determined for beef cattle. Effects of supplementation of long‐acting progesterone (P4) on Days 2 or 3 post‐ovulation on development, function and regression of corpus luteum (CL) were studied in beef cattle. Cows were synchronized with an oestradiol/P4‐based protocol and treated with 150 or 300 mg of long‐acting P4 on Day 2 or 3 post‐ovulation (6–7 cows/group). Colour‐doppler ultrasound scanning and blood sample collection were performed from Day 2–21.5. Plasma P4 concentrations were greater (p < 0.05) from Day 2.5–5.5 in the Day 2‐treated groups and from Day 3.5–5.5 in the Day 3‐treated cows than in the control group. CL area and blood flow during Day 2–8.5 did not differ (p > 0.05) among groups, suggesting no effect of P4 treatment on luteal development. The frequency of cows that began luteolysis before Day 15 was greater (p < 0.04) in cows treated with 300 mg than in the controls, but there were no differences between non‐treated and 150 mg‐treated cows. The interval from pre‐treatment ovulation to functional and structural luteolysis was shorter (p < 0.01) in the combined P4‐treated groups than in the control cows. In conclusion, was showed for the first time that long‐acting P4 supplementation on Day 2 or 3 post‐ovulation increases P4 concentrations for ≥3 day, has no effect on luteal development, but anticipates the beginning of luteolysis in beef cattle.     

Pharmacokinetic and efficacy studies on bath-administering potentiated sulphonamides in Atlantic halibut, Hippoglossus hippoglossus L.

The uptake, metabolism, tissue distribution and excretion of four sulphonamides and trimethoprim following bath treatment of Atlantic halibut, Hippoglossus hippoglossus L., were studied. Bath treatment using a concentration of 200 μg ml^–1 for 72 h resulted in peak sulphadimidine concentrations in muscle and abdominal organ homogenates of 32·6 and 68·2 μg g^–1, respectively. The corresponding values were 24·4 and 73·4 μg g^–1 for sulphaguanidine, 6·1 and 45·1 μg g^–1 for sulphamethoxazole, 2·1 and 15·1 μg g^–1 for sulphadimethoxine, and 99 and 169 μg g^–1 for trimethoprim. After a 72-h treatment, approximately 90% of the sulphadimethoxine and sulphamethoxazole present in tissues was found as the N⁴-acetylated metabolite, whereas for sulphadimidine and sulphaguanidine, the N⁴-acetylations were from 9 to 23%. Based on these preliminary absorption studies, sulphadimidine was chosen as the companion sulphonamide to trimethoprim. Using a combination of 500 μg ml^–1 sulphadimidine and 100 μg ml^–1 trimethoprim in the bath for 72 h, peak muscle and liver concentrations of 262 and 312 μg g^–1, respectively, for sulphadimidine and 32·8 and 83·6 μg g^–1, respectively, for trimethoprim were achieved. Elimination half-lives (t_1/2β) for sulphadimidine were calculated to be 35 and 48 h for muscle and liver, respectively. The corresponding values for trimethoprim were 98 and 116 h. Using the 95% confidence limit for single observations (95% prediction limit) and a maximum residue limit (MRL) value of 0·05 μg g^–1 for trimethoprim and 0·1 μg g^–1 for sulphadimidine, the elimination times (E_t95) for muscle and liver were calculated to be 18 and 26 days, respectively, for sulphadimidine and 40 and 55 days, respectively, for trimethoprim. Minimum inhibitory concentrations (MIC) values against selected strains of Vibrio sp. were equal to or above 128 μg ml^–1 for sulphadimidine, between 0·25 and 4·00 μg ml^–1 for trimethoprim and between 0·4 and 8·8 μg ml^–1 for various ratios of the sulphadimidine:trimethoprim combination. In the tested ratios, the combined antimicrobial action of trimethoprim and sulphadimidine were synergistic, as revealed by their fractional inhibitory concentration (FIC) indices. In general, the 1:5 trimethoprim sulphadimidine ratio showed the highest degree of synergism. Using a combination of 500 μg ml^–1 sulphadimidine and 100 μg ml^–1 trimethoprim in the bath for 72 h, concentrations greater than a MIC value of 0·8 μg ml^–1 were maintained for 22 days in muscle and 29 days in liver. In a laboratory challenge experiment using Vibrio anguillarum strain HI 11347, a significantly lower mortality was observed in the drug-treated group (40%) compared to the untreated control group (93%).     

Residue levels of enrofloxacin and ciprofloxacin in processed animal by‐products used in Atlantic salmon feeds and their long‐term carry‐over to the edible part of the fish

Residue levels of the antibacterials enrofloxacin and ciprofloxacin were analysed in 15 commercially relevant animal by‐products (ABPs). Enrofloxacin was detected in all ABPs, and ciprofloxacin was detected in 11 of 15 ABP samples. Feed to muscle and skin carry –over of low background enro‐ and ciprofloxacin levels were assessed by applying a simple toxicokinetic model. The muscle and skin uptake and elimination rates were established in Atlantic salmon (Salmo salar L.) fed enrofloxacin enriched diets (100 μg kg^?1 ‘low’ and 4000 μg kg^?1 ‘high’) in triplicate for 41 days followed by a 90 days depuration period. The terminal half‐lives were 17 ± 0.4 and 18 ± 0.7 days, and uptake rates were 9.3 ± 3.3 and 11 ± 3.1 (day^?1) for the ‘low’ and ‘high’ groups, respectively. Only fish fed high background levels had quantifiable levels of the metabolite ciprofloxacin with a formation of 0.25 ± 0.01% day^?1. The toxicokinetic carry‐over model predicted muscle and skin steady state levels of 1.8 μg kg^?1 when fed theoretically high enrofloxacin levels (158 μg kg^?1), which is below the EU limit of 100 μg kg^?1 for enrofloxacin in finfish food products. The antibacterial residue levels could however be detected in EU food surveillance programmes.     

水产养殖治疗性药物的使用、法规和药残控制

亚洲国家水产养殖有悠久的历史.过去几十年里,水产养殖已经从亚洲快速扩展到世界其他地区并出现了许多先进的养殖技术.2004年全球食品供应中,水产养殖产量是5.94×107 t[1].