不同水平的蛋氨酸锌对肉用仔鸡生产性能和免疫的影响

试验采用完全随机试验设计,将1日龄的罗斯308肉鸡360只分成6组,每组3个重复,每个重复20只鸡,研究蛋氨酸锌(ZnMet)对肉鸡平均日增重(ADG)、平均日采食量(ADFI)和料重比(F/G)以及免疫器官指数和ND抗体效价的影响。日粮处理组为在不添加锌的玉米-豆粕型基础饲粮基础上分别添加20、40、60、80和100mg/kg水平的蛋氨酸锌(以锌计),结果表明,饲粮中添加蛋氨酸锌能提高肉鸡的平均日增重,改善料重比和免疫功能,60～80mg/kg为适宜添加量。     

Behavior of Insecticide Chlorpyrifos on Soils and Sediments with Different Organic Matter Content from Provincia de Buenos Aires, República Argentina

Buenos Aires Province (República Argentina) has undergone, in the last years, a great increase in agricultural activities based on the incorporation of new technologies and reduction of diversity to meet the increasing food demand. The increase of intensive agricultural systems in Argentina involves the use of fertilizers and pesticides such as herbicides, insecticides, and fungicides. Chlorpyrifos is one of the insecticides most widely used in these crops and constitutes a risk for human health, birds, and aquatic biota such as macroinvertebrates and fishes. In order to assess the possible contamination that the use of this product may represent for the environment, it is necessary to study its interaction with the different types of soils because fate and transport of environmental pollutants may be influenced by their interactions with soil particles. The behavior of chlorpyrifos was analyzed through the study of the recoveries from spiked solid environmental matrices. A strong dependence with organic matter content was observed along with an important dependence with the initial concentrations employed. Here, we show that chlorpyrifos behavior on solid matrices not only depends on soil chemical composition. A significant dependence of recovery percentages with initial concentrations of the pesticide was evident in all cases. Recovery percentages decreased with an increase of the initial concentration employed, no matter the variations in matrices of chemical compositions.     

Untargeted Metabolomics Approach for the Discovery of Environment-Related Pyran-2-Ones Chemodiversity in a Marine-Sourced Penicillium restrictum

Very little is known about chemical interactions between fungi and their mollusc host within marine environments. Here, we investigated the metabolome of a Penicillium restrictum MMS417 strain isolated from the blue mussel Mytilus edulis collected on the Loire estuary, France. Following the OSMAC approach with the use of 14 culture media, the effect of salinity and of a mussel-derived medium on the metabolic expression were analysed using HPLC-UV/DAD-HRMS/MS. An untargeted metabolomics study was performed using principal component analysis (PCA), orthogonal projection to latent structure discriminant analysis (O-PLSDA) and molecular networking (MN). It highlighted some compounds belonging to sterols, macrolides and pyran-2-ones, which were specifically induced in marine conditions. In particular, a high chemical diversity of pyran-2-ones was found to be related to the presence of mussel extract in the culture medium. Mass spectrometry (MS)- and UV-guided purification resulted in the isolation of five new natural fungal pyran-2-one derivatives—5,6-dihydro-6S-hydroxymethyl-4-methoxy-2H-pyran-2-one (1), (6S, 1’R, 2’S)-LL-P880β (3), 5,6-dihydro-4-methoxy-6S-(1’S, 2’S-dihydroxy pent-3’(E)-enyl)-2H-pyran-2-one (4), 4-methoxy-6-(1’R, 2’S-dihydroxy pent-3’(E)-enyl)-2H-pyran-2-one (6) and 4-methoxy-2H-pyran-2-one (7)—together with the known (6S, 1’S, 2’S)-LL-P880β (2), (1’R, 2’S)-LL-P880γ (5), 5,6-dihydro-4-methoxy-2H-pyran-2-one (8), (6S, 1’S, 2’R)-LL-P880β (9), (6S, 1’S)-pestalotin (10), 1’R-dehydropestalotin (11) and 6-pentyl-4-methoxy-2H-pyran-2-one (12) from the mussel-derived culture medium extract. The structures of 1-12 were determined by 1D- and 2D-MMR experiments as well as high-resolution tandem MS, ECD and DP4 calculations. Some of these compounds were evaluated for their cytotoxic, antibacterial, antileishmanial and in-silico PTP1B inhibitory activities. These results illustrate the utility in using host-derived media for the discovery of new natural products.     

Genetic Characterization of Cryptosporidium spp. in Diarrhoeic Children from Four Provinces in South Africa

The diversity of Cryptosporidium at species, subtype family and subtype level in diarrhoeic children was investigated in four provinces in South Africa. A total of 442 stool samples from children <5 years of age were collected under a large rotavirus surveillance programme and analysed by Ziehl–Neelsen acid‐fast staining. Fifty‐four (12.2%) were positive for Cryptosporidium, of which 25 were genotyped by polymerase chain reaction (PCR)–restriction fragment length polymorphism (RFLP) and DNA sequence analyses of the 18S rRNA gene. The majority of genotyped specimens were identified as C. hominis (76%), and a high genetic diversity was found with five different C. hominis subtype families (Ia, Ib, Id, Ie and If). Cryptosporidium parvum was found in 20% of the isolates, and three subtype families were identified (IIc, IIe and IIb), with subtype family IIc being the most common. One specimen was identified as C. meleagridis of the subtype family IIId. These results are in accordance with findings from other developing countries and report for the first time the presence in South Africa of C. meleagridis, various subtypes of C. parvum and the subtype family Ie of C. hominis. The results suggest that C. hominis and anthroponotic C. parvum subtypes are the major cause of cryptosporidiosis in South Africa. Further molecular studies are needed to better understand the epidemiology and public health importance of Cryptosporidium in humans in South Africa.     

Die potensiaal vir droëland aangeplante weiding in die vrystaatstreek

Uittreksel

Die uitbreidingspotensiaal van aangeplante weiding in die Vrystaatstreek is ondersoek. Die potensiaalomskrywing is gedoen aan die hand van klimatologiese oorwegings, beskikbaarheid van grond en die winsgewendheid van aangeplante weiding teen‐oor veld, mielie‐ en koringproduksie.

Die ondersoek toon aan dat daar aansienlike potensiaal vir die uitbreiding van aangeplante weiding bestaan sover dit die reenval en beskikbare grondoppervlakte aanbetref. Voorts is dit duidelik dat dit nie ekonomies geregverdig is om veld in ‘n redelike toestand vir aangeplante weiding om te ploeg nie. Dit word betwyfel of dit winsgewend is om marginale lande van koring‐ en mielieverbouing te onttrek en met aangeplante grasweidings te vestig waar gemiddelde en onder gemiddelde bestuur toegepas word. Droëlandlusern, benut deur wolskape en melkkoeie, en sorghums benut deur melkkoeie, blyk ekonomies geregverdig op marginale lande te wees.     

Voorlopige evaluasie van sporobolus fimbriatus as aangeplante weiding in die sentrale oranje‐vrystaat

Uittreksel

Die potensiaal van Sporobolus fimbriatus as aangeplante weiding is ten opsigte van relatiewe groeitempo, kumulatiewe groei, droëmateriaalproduksie, weikapasiteit, blaar : stingel verhouding en kwaliteit (ruproteïen en verteerbaarheid) geëvalueer.

Die groeipatroon is tipies van ‘n tropiese grasspesie. Die droëmateriaalproduksie van onbeweide en beweide S. fimbriatus was gemiddeld 3 329 kg/ha en 2720 kg/ha onderskeidelik. ‘n Gemiddelde weikapasiteit van 4,22 ha/GVE/jaar is verkry. Die blaar : stingelverhouding het heelwat tussen seisoene verskil, terwyl die verhouding deurgaans meer gunstig onder snytoe‐stande as onder beweiding was. Beide die ruproteïeninhoud en verteerbaarheid van dieregeselekteerde plantmateriaal het feitlik deurgaans aan die behoefte van herkouers voldoen.     

Distribution of the portunid crab Ovalipes punctatus (De Haan) in Algoa Bay and salinity and temperature tolerances of its zoeae

The three-spot swimming crab Ovalipes punctatus is commonly found in surf zones off sandy beaches in Algoa Bay. It is exclusively marine and occurs down to a depth of 38 m. Large crabs were found close inshore while smaller crabs were predominantly found in deeper water, suggesting that settlement mainly occurs offshore in water 25 – 38 m deep. Gravid females were found closer inshore in shallow water. The zoeae could not tolerate high temperatures (>27,5 °C) or low salinities (<15‰). The optimal temperatures and salinities for survival of the zoeae were 15–22 °C and 34–35‰ respectively.     

Out-of-season breeding of milk goats--the effect of light treatment,melatonin and breed

The purpose of this study was to evaluate the effectivity of melatonin in addition to light treatment (exposure to 2 hours of light during the night = a long-day photoperiod) to modify the breeding season of Saanen and cross-bred milk goats and to compare the difference between the breeds. Twenty-two Saanen and 22 cross-bred does were randomly divided into 3 treatment groups. Group 1 (controls) received no treatment, Group 2 received light treatment for 37 days and Group 3 received light treatment plus melatonin implants after the light treatment. After a further 35 days the 3 groups were brought together and a billy goat that had also been exposed to the extra light at night, had received a melatonin implant and had been isolated from the does during the treatment period, was introduced to the does for natural mating. Ultrasound scanning was used to diagnose pregnancy and all the pregnant goats kidded. Significantly more Saanen does compared to cross-bred does (P = 0.018) became pregnant and kidded after natural mating, when the group that received melatonin as well as light treatment was compared to the group that received light treatment only. Compared to light treatment only, the addition of melatonin to light treatment improved (P = 0.0028) conception after natural mating, in both the Saanen and the cross-bred does.