The Advantages of Combining Low‐Density Lipoproteins with Glutamine for Cryopreservation of Canine Semen

Twenty sperm samples from five dogs were frozen in liquid nitrogen at ?196°C in 16 different media, two control media containing 20% egg yolk and 6% low‐density lipoproteins (LDL); 10 test media containing 6% LDL (the active cryoprotective ingredient of chicken egg yolk) combined with 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mmol of glutamine respectively at 4%, 5%, 7%, and 8% LDL. Following thawing, sperm mobility was assessed using an image analyser, HAMILTON THORN CERROS 12. The percentage of mobile spermatozoa was 62.05% in the 6% LDL + 20 mmol glutamine medium compared with 48.90% in the egg yolk‐based medium (p < 0.05) or 57.55% for the 6% LDL medium (p < 0.05). Furthermore, in most cases, the motility parameters (average path velocity, curvilinear velocity, straight line velocity) in the 6% LDL + 20 mmol glutamine medium, were superior, to a statistically significant extent, to those in the control media. Finally, the 6% LDL + 20 mmol glutamine combination provides spermatozoa with better protection during freezing than egg yolk or the 6% LDL medium alone in terms of acrosome integrity (fluorescein isothiocyanate–Pisum sativum agglutinin test: p < 0.05), the flagellar plasma membrane (hypo‐osmotic test: p < 0.05 for 6% LDL), the DNA (acridine orange test; no significant difference) and the integrity of the acrosome (Spermac^® test: no significant difference).     

矮小型肉种鸡的新看法

"矮小型"肉种鸡进入市场已几乎有40年的历史,并且一直以来在家禽行业内存有争论,一些人表示支持利用这一鸡种,但也有些人表示对其不感兴趣。两者往往都夸大其有利或不利的一面,或者更倾向于考虑市场行情和环境条件的不同。让我们以实事求是的态度看待此鸡种!     

橡胶树品种热研88-13易碎胚性愈伤组织的诱导及其植株再生

以高产优质橡胶品种热研88-13的幼嫩种子内珠被为外植体材料,对愈伤组织诱导培养基和继代培养基中的影响因素如植物生长调节剂的种类和浓度、钙离子浓度等进行了研究。经过连续6个月的继代选择培养,逐渐诱导出易碎的胚性愈伤组织,适宜的易碎胚性愈伤组织诱导培养基为:MH基本成分,添加0.5 mg/L KT,2.0 mg/L 2,4-D,11.0 mmol/L CaCl2,80.0 g/L蔗糖和2.0 g/L Phytagel。组织学切片证明长期继代培养的易碎胚性愈伤组织维持了胚性的状态。取继代培养2 a多的易碎胚性愈伤组织诱导体细胞胚的形成,得到了16 000多个体细胞胚。将这些胚进行进一步的转移培养,得到了115株再生植株。     

Study of an Amphoteric Surfactant in a Soil Decontamination Process Using ANS Enhanced Fluorescence: Micellar Behavior and Dosing in Synthetic and Soil Solutions

Cocamidopropyl hydroxysultaine (CAS) has been used in a pilot plant study as a biodegradable surfactant for the extraction of polycyclic aromatic hydrocarbons (PAHs) and lead (Pb) from contaminated soils. The soil treatment has been done in flotation cells with a concentration of 0.20 g CAS L⁻¹ in saline conditions (3 M NaCl) and using a pulp density of 20% (w/w). The process integrates the recirculation of the liquid phases separated from the soil by centrifugation or filtration. Thus, it was necessary to understand CAS-PAHs micellar behavior and to follow the behavior and the fate of the surfactant in the process. 1-8-anilino-naphthalene sulfonate (ANS) is used as a fluorophor compound in the ANS enhanced fluorescence technique. A three-dimensional model detailing the change in the micellar behavior at high NaCl concentration and at different pH has been established. Fluorescence results of centrifuged soil matrix containing CAS have been compared to the results from synthetic solutions assays. A method allowing an accurate titration of the CAS has been developed by using the exact same matrix of the soil as the tested samples for the preparation of the calibration curves. The study of the surfactant concentration in the process has been performed and allows the adjustment of the CAS concentration in the recirculated water.     

Does the influence of earthworms on water infiltration, nitrogen leaching and soil respiration depend on the initial soil bulk density? A mesocosm experiment with the endogeic species Metaphire posthuma

Soil compaction has a negative impact on both earthworm abundance and diversity. Recent studies, however, suggest that earthworm cast properties are not influenced by the initial soil bulk density. With time, earthworms could therefore transform soils with different bulk densities into a soil with the same physical state and thus with a similar ecological functioning. This study aimed to test this hypothesis in two laboratory incubation experiments. First, we measured the influence of soil bulk density (1.1 or 1.4?g?cm^?3) on the production of cast by the endogeic earthworm species Metaphire posthuma. In a second experiment, we investigated the effect of M. posthuma on water infiltration, NH ₄ ⁺ , and NO ₃ ^? leaching and soil respiration at the same two soil bulk densities. Although initially higher, earthworm casting activity in soil at 1.4?g?cm^?3 decreased until it reached the same level of activity as earthworms in soil at 1.1?g?cm^?3. This behavioral plasticity led to a transformation of compacted and loose soils, with their own functioning, to a third and similar state with similar hydraulic conductivity, nitrogen leaching, and soil respiration. The consequences for soil organization and soil functioning are discussed.     

Estimation of transmission parameters of a fluoroquinolone-resistant Escherichia coli strain between pigs in experimental conditions

Antimicrobial resistance is of primary importance regarding public and animal health issues. Persistence and spread of resistant strains within a population contribute to the maintenance of a reservoir and lead to treatment failure. An experimental trial was carried out to study the horizontal transmission of a fluoroquinolone-resistant Escherichia coli strain from inoculated to naïve pigs. All naïve contact pigs had positive counts of fluoroquinolone-resistant E. coli after only two days of contact. Moreover, re-infections of inoculated pigs caused by newly contaminated animals were suspected. A maximum likelihood method, based on a susceptible-infectious-susceptible (SIS) model, was used to determine the transmission parameters. Two transmission levels were identified depending on the quantity of bacteria shed by infected individuals: (i) low-shedders with bacterial counts of resistant E. coli in the faeces between 5*10³ and 10⁶ CFU/g (β_L = 0.41 [0.27; 0.62]), (ii) high shedders with bacterial counts above 10⁶ CFU/g (β_H = 0.98 [0.59; 1.62]). Hence, transmission between animals could be pivotal in explaining the persistence of resistant bacteria within pig herds.     

Issues and special features of animal health research

ABSTRACT: In the rapidly changing context of research on animal health, INRA launched a collective discussion on the challenges facing the field, its distinguishing features, and synergies with biomedical research. As has been declared forcibly by the heads of WHO, FAO and OIE, the challenges facing animal health, beyond diseases transmissible to humans, are critically important and involve food security, agriculture economics, and the ensemble of economic activities associated with agriculture. There are in addition issues related to public health (zoonoses, xenobiotics, antimicrobial resistance), the environment, and animal welfare.Animal health research is distinguished by particular methodologies and scientific questions that stem from the specific biological features of domestic species and from animal husbandry practices. It generally does not explore the same scientific questions as research on human biology, even when the same pathogens are being studied, and the discipline is rooted in a very specific agricultural and economic context.Generic and methodological synergies nevertheless exist with biomedical research, particularly with regard to tools and biological models. Certain domestic species furthermore present more functional similarities with humans than laboratory rodents.The singularity of animal health research in relation to biomedical research should be taken into account in the organization, evaluation, and funding of the field through a policy that clearly recognizes the specific issues at stake. At the same time, the One Health approach should facilitate closer collaboration between biomedical and animal health research at the level of research teams and programmes.     

Antibody response against Trichinella spiralis in experimentally infected rats is dose dependent

ABSTRACT: Domestic pigs are the main representatives of the domestic cycle of Trichinella spiralis that play a role in transmission to humans. In Europe, backyard pigs of small household farms are the most important risks for humans to obtain trichinellosis. Rats might play a role in the transmission of Trichinella spiralis from domestic to sylvatic animals and vice versa. In order to be able to investigate the role of wild rats in the epidemiology of T. spiralis in The Netherlands, we studied the dynamics of antibody response after T. spiralis infections in experimental rats, using infection doses ranging from very low (10 muscle larvae, ML, per rat) to very high (16 000 ML per rat). To evaluate the feasibility of rats surviving high infection doses with T. spiralis, clinical and pathological parameters were quantified. Serological tools for detecting T. spiralis in rats were developed to quantitatively study the correlation between parasite load and immunological response. The results show that an infection dose-dependent antibody response was developed in rats after infection with as low as 10 ML up to a level of 10 000 ML. A positive correlation was found between the number of recovered ML and serum antibody levels, although specific measured antibody levels correspond to a wide range of LPG values. Serum antibodies of rats that were infected even with 10 or 25 ML could readily be detected by use of the T. spiralis western blot 2 weeks post infection. We conclude that based on these low infection doses, serologic tests are a useful tool to survey T. spiralis in wild rats.