水质量对饮水免疫效果的影响

饮水免疫接种成功与否取决于管理条件，例如水质量、氯离子中和作用、疫苗溶液的分配和利用以及疫苗溶液的摄入率。     

Evidence of diadromy in the French Polynesian Kuhlia malo (Teleostei: Percoidei) inferred from otolith microchemistry analysis

Abstract – Strontium/Calcium (Sr/Ca) and Barium/Calcium (Ba/Ca) ratios were measured in 60 otoliths of the French Polynesian flagtail Kuhlia malo. Both elemental ratios were needed to correctly distinguish residence in marine, brackish and fresh water. High Sr/Ca and low Ba/Ca around the nucleus of all otoliths provided evidence of marine residency during the early life of all individuals. At about 0.5 mm from the core, Ba/Ca increased rapidly and remained high in all otoliths. High and unstable Sr/Ca ratios were attributed to estuarine residency, whereas low and stable Sr/Ca ratios were attributed to freshwater residency. These chemical signatures inferred that following recruitment to rivers, some fish remained in the estuary, while others moved upstream. Some individuals shared their time between fresh and brackish waters later in life. The findings of this study have important implications for the protection of nearshore, brackish and freshwater environments for the conservation of this French Polynesian diadromous species.     

Detection of Cryptosporidium oocysts in goat kid faeces: comparison of a latex agglutination test with three other conventional techniques

Detection of Cryptosporidium oocysts from goat kid faeces: comparison of a latex agglutination test with three other conventional techniques. A quantitative latex agglutination test (QLAT) with monoclonal antibodies for the detection of Cryptosporidium oocysts in faeces was compared with 3 other conventional techniques: Heine staining on faecal smears (HS) giving semi-quantitative results (scores from 1 to 5), sucrose flotation on diluted faeces (SF) with results expressed in oocysts/g of faeces (opg), direct ELISA (DE) giving qualitative results. Goat kid unconcentrated faecal samples (234) from 8 farms were processed according to the 4 techniques. Data were analyzed with Win Episcope 1.0 and Testview 1.1 softwares. The oocyst outputs ranged from 100 000 (detection limit for SF) to 200 millions opg (mean: 15.2 millions opg). A very good agreement was recorded between QLAT and HS, SF, DE: Kappa values ranged between 0.82 and 0.90. When considering the samples exhibiting oocysts (or not) as positive (or negative) using both HS and SF (n = 219), the sensitivity and specificity of QLAT were respectively 95.1 and 96.0%. The lack of sensitivity was observed in faeces harboring a few oocysts (< or = 200 000 opg, scores < or = 2) whereas the lack of specificity was only observed in 3 samples originating from the same farm. A significant correlation was calculated between the percentage of agglutination in QLAT and the number of oocysts in SF or scores in HS (Spearman correlation ranging from 0.45 to 0.48, p < 0.001). QLAT is a rapid, simple and reliable tool for routine detection of Cryptosporidium oocysts in faeces.     

Dairy science and health in the tropics: challenges and opportunities for the next decades

In the next two decades, the world population will increase significantly; the majority in the developing countries located in the tropics of Africa, Asia, Latin America, and the Caribbean. To feed such a population, it is necessary to increase the availability of food, particularly high-value animal protein foods produced locally, namely meat and dairy products. Dairy production in tropical regions has a lot of growth potential, but also poses a series of problems, particularly as dairy production systems were developed in temperate countries and in most cases are difficult to implement in the tropics. Drawbacks include hot weather and heat stress, the lack of availability of adequate feeds, poor infrastructure, and cold chain and the competition with cheap imports from temperate countries. This position paper reviews the major drawbacks in dairy production for the five major dairy species: cattle, water buffalo, sheep, goat, and camel, as well as the future trends in research and development. It also concerns the major trends in reproduction and production systems and health issues as well as environmental concerns, particularly those related to greenhouse gas emissions. Tropical Animal Health and Production now launches a topical collection on Tropical Dairy Science. We aim to publish interesting and significant papers in tropical dairy science. On behalf of the editorial board of the Tropical Animal Health and Production, we would like to invite all authors working in this field to submit their works on this topic to this topical collection in our journal.

     

Application of a putative fatty-acid binding protein to discriminate serologically the two European quarantine root-knot nematodes, Meloidogyne chitwoodi and M. fallax, from other Meloidogyne species

Two major proteins, Mcf-A67 and Mcf-B66, were identified by mini two-dimensional polyacrylamide gel electrophoresis in order to distinguish the two European quarantine root-knot nematodes, Meloidogyne chitwoodi and M. fallax, from eight other species. These quarantine proteinic markers have been microsequenced after enzymatic digestion. The internal amino acid sequences exhibit similarities to members of a family of low molecular weight intracellular lipid-binding proteins. Moreover, to explore a simple, rapid, and inexpensive way to identify the two quarantine nematodes, dot blot hybridizations were performed using an antiserum (A67) produced from the longest amino-acid sequence of the protein Mcf-A67. Although several proteins stained on the M. chitwoodi and M. fallax western blot membranes, the two nematodes were easily distinguished from other root-knot nematodes, on dot blot assays with soluble proteins extracted from a single female. Because of its specificity and sensitivity, the use of the A67 antiserum to improve the diagnosis of the two European quarantine root-knot nematodes is discussed.     

Modelling transport of chokka squid (Loligo reynaudii) paralarvae off South Africa: reviewing,testing and extending the ‘Westward Transport Hypothesis’

Annual landings of chokka squid (Loligo reynaudii), an important fishing resource for South Africa, fluctuate greatly, and are believed to be related to recruitment success. The ‘Westward Transport Hypothesis’ (WTH) attributes recruitment strength to variability in transport of newly hatched paralarvae from spawning grounds to the ‘cold ridge’ nursery region some 100–200 km to the west, where oceanographic conditions sustain high productivity. We used an individual‐based model (IBM) coupled with a 3‐D hydrodynamic model (ROMS) to test the WTH and assessed four factors that might influence successful transport – Release Area, Month, Specific Gravity (body density) and Diel Vertical Migration (DVM) – in numerical experiments that estimated successful transport of squid paralarvae to the cold ridge. A multifactor ANOVA was used to identify the primary determinants of transport success in the various experimental simulations. Among these, release area was found to be the most important, implying that adult spawning behaviour (i.e., birth site fidelity) may be more important than paralarval behaviour in determining paralarval transport variability. However, specific gravity and DVM were found to play a role by retaining paralarvae on the shelf and optimizing early transport, respectively. Upwelling events seem to facilitate transport by moving paralarvae higher in the water column and thus exposing them to faster surface currents.     

A 13CO2 Enrichment Experiment to Study the Synthesis Pathways of Polyunsaturated Fatty Acids of the Haptophyte Tisochrysis lutea

The production of polyunsaturated fatty acids (PUFA) in Tisochrysis lutea was studied using the gradual incorporation of a ¹³C-enriched isotopic marker, ¹³CO₂, for 24 h during the exponential growth of the algae. The ¹³C enrichment of eleven fatty acids was followed to understand the synthetic pathways the most likely to form the essential polyunsaturated fatty acids 20:5n-3 (EPA) and 22:6n-3 (DHA) in T. lutea. The fatty acids 16:0, 18:1n-9 + 18:3n-3, 18:2n-6, and 22:5n-6 were the most enriched in ¹³C. On the contrary, 18:4n-3 and 18:5n-3 were the least enriched in ¹³C after long chain polyunsaturated fatty acids such as 20:5n-3 or 22:5n-3. The algae appeared to use different routes in parallel to form its polyunsaturated fatty acids. The use of the PKS pathway was hypothesized for polyunsaturated fatty acids with n-6 configuration (such as 22:5n-6) but might also exist for n-3 PUFA (especially 20:5n-3). With regard to the conventional n-3 PUFA pathway, Δ6 desaturation of 18:3n-3 appeared to be the most limiting step for T. lutea, “stopping” at the synthesis of 18:4n-3 and 18:5n-3. These two fatty acids were hypothesized to not undergo any further reaction of elongation and desaturation after being formed and were therefore considered “end-products”. To circumvent this limiting synthetic route, Tisochrysis lutea seemed to have developed an alternative route via Δ8 desaturation to produce longer chain fatty acids such as 20:5n-3 and 22:5n-3. 22:6n-3 presented a lower enrichment and appeared to be produced by a combination of different pathways: the conventional n-3 PUFA pathway by desaturation of 22:5n-3, the alternative route of ω-3 desaturase using 22:5n-6 as precursor, and possibly the PKS pathway. In this study, PKS synthesis looked particularly effective for producing long chain polyunsaturated fatty acids. The rate of enrichment of these compounds hypothetically synthesized by PKS is remarkably fast, making undetectable the ¹³C incorporation into their precursors. Finally, we identified a protein cluster gathering PKS sequences of proteins that are hypothesized allowing n-3 PUFA synthesis.     

Euthanasia of honey-bee colonies: Proposal of a standard method

Honey bees are most often kept for production purposes. Sanitary, regulatory, or zootechnical circumstances may lead the beekeeper or the veterinarian to dispose of a honey-bee colony. Unfortunately and at present, no standard method of euthanasia exists, leaving the door open to many more or less acceptable practices. Based on a short survey of current practices in 8 countries, we list and rank these methods. Although imperfect, the sulfur dioxide technique appears to be the most efficient. We suggest that it should become the reference method to be taught and incorporated into veterinary and regulatory guidelines.