Effect of the Medium Replacement Interval on the Viability,Growth and In Vitro Maturation of Isolated Caprine and Ovine Pre‐Antral Follicles

The aim of the present study was to evaluate the effects of different medium replacement intervals on the viability, antral cavity formation, growth and in vitro maturation (IVM) of oocytes from caprine and ovine pre‐antral follicles. Pre‐antral ovarian follicles (≥150 μm) were isolated from the ovarian cortex of goats and sheep and were individually cultured for 24 days using two different medium replacement intervals [2 days (T₁) or 6 days (T₂)]. Follicle development was evaluated on the basis of antral cavity formation, increases in follicular diameter and the presence of healthy cumulus oocyte complexes and fully grown oocytes. For caprine species, results showed a higher percentage (p < 0.05) of viable follicles in T₁ than T₂ from day 6 until the end of the culture. In addition, when comparing both treatments after the same culture duration, the rate of antrum formation was significantly higher in T₁ than in T₂ from day 12 onwards. Yet, in ovines, when both treatments were compared on day 24 of the culture, there were more viable follicles in T₂ than in T₁ (p < 0.05). In the caprine species, percentages of fully grown oocytes (≥110 μm) acceptable for IVM after 24 days of culture were significantly higher in normal follicles cultured in T₁ (30.0%) than in T₂ (6.7%; p < 0.05). On the other hand, in ovines, at the end of the culture, the percentage of oocytes destined for IVM was higher in T₂ than in T₁ (23.5% vs 2.9%; p < 0.05). In conclusion, under the same conditions, the frequency of medium replacement significantly affected the in vitro development of caprine and ovine pre‐antral follicles. To improve the efficiency of the culture system, the medium must be replaced every 2 and 6 days for goat and sheep pre‐antral follicles, respectively.     

Antioxidant activity of uruguayan propolis. In vitro and cellular assays

The antioxidant capacity of propolis from the southern region of Uruguay was evaluated using in vitro as well as cellular assays. Free radical scavenging capacity was assessed by ORAC, obtaining values significantly higher than those of other natural products (8000 μmol Trolox equiv/g propolis). ORAC values correlated well with total polyphenol content (determined by Folin-Ciocalteu method) and UV absorption. Total polyphenol content (150 mg gallic acid equiv/g propolis) and flavonoids (45 mg quercetin equiv/g propolis) were similar to values reported for southern Brazilian (group 3) and Argentinean propolis. Flavonoid composition determined by RP-HPLC indicates a strong poplar-tree origin. Samples high in polyphenols efficiently inhibit low-density lipoprotein lipoperoxidation and tyrosine nitration. In addition, Uruguayan propolis was found to induce the expression of endothelial nitric oxide synthase and inhibit endothelial NADPH oxidase, suggesting a potential cardiovascular benefit by increasing nitric oxide bioavailability in the endothelium.     

Synthesis of a combinatorial library of amides and its evaluation against the fall armyworm, Spodoptera frugiperda

The fall armyworm Spodoptera frugiperda is a polyphagous pest that causes important damage in different regions of America and mainly affects corn crops in both tropical and subtropical areas. Currently, control relies on both transgenic plants and/or chemical pesticides. In this work we describe the preparation of an indexed combinatorial library of amides and its toxic effect by contact against S. frugiperda . (E)-1-(1-Piperidinyl)-3-[4-(trifluoromethoxy)phenyl]-2-propen-1-one was the most active compound with an LD(50) = 0.793 μg mg(-1) of larva. This amide was also evaluated by ingestion and at the lowest concentration (1 mg kg(-1)) achieved 83.3% mortality.     

Geomorphology and soils distribution under paraglacial conditions in an ice-free area of Admiralty Bay, King George Island, Antarctica

The main pedological, geomorphological and cryogenic features of Keller Peninsula, part of Admiralty Bay, King George Island, Maritime Antarctica, were mapped and quantified with emphasis on the relationship between the ice retreat process, melt-out, landform development and soil distribution. Moraines, protalus, scree slopes, inactive glacial cirques, uplift marine terraces, biogenic landforms, arêtes and Felsenmeer were mapped. Scree slope is the main landform, covering approximately 25% of the peninsula, indicating prominent paraglacial features. Inherited, glacial landforms, such as lateral moraines, highland plateau and exhumed U shaped-valleys, are now being exposed in north Keller by ice shrinkage of former ice protecting cover. Landforms influenced soil formation and stability. Cryosols and Leptosols (WRB) roughly corresponding to Gelisols and Entisols (SSS), respectively, are the most common soil classes, with an overall tendency of absent permafrost in the coastal areas, changing to sporadic permafrost at mid-slope, and discontinuous permafrost with greater altitude and substrate stability.     

Determination of the quality index of a Paleudult under sunflower culture and different management systems

Soil is an essential resource for life and its properties are susceptible to be modified by tillage systems. The impact of management practices on soil functions can be assessed through a soil quality index. It is interesting to assess soil quality in different soil types. Therefore, the aim of this study was to determine the soil quality index of a Paleudult under different management conditions and sunflower culture. The experiment was carried out in Botucatu (SP, Brazil), in an 11-year non-tilled area used for growing soybean and maize during summer and black oat or triticale in winter. Four management systems were considered: no-tillage with a hoe planter (NTh), no-tillage with a double-disk planter (NTd), reduced tillage (RT) and conventional tillage (CT). Soil samples were taken from the planting lines at harvest time. To determine the soil quality indices, following the methodology proposed by Karlen and Stott (1994), three main soil functions were assessed: soil capacity for root development, water storage capacity of the soil and nutrient supply capacity of the soil. The studied Paleudult was considered a soil with good quality under all the observed management systems. However, the soil quality indices varied between treatments being 0.64, 0.68, 0.86 and 0.79 under NTh, NTd, RT and CT, respectively. Physical attributes such as resistance to penetration and macroporosity increased the soil quality index in RT and CT compared to NTh and NTd. The soil quality indices obtained suggested that the evaluated soil is adequate for sunflower production under our study conditions. In view of the SQI values, RT is the most suitable management for this site since it preserves soil quality and provides an acceptable sunflower yield.     

Ruminal and histological characteristics and nitrogen balance in lamb fed diets containing cactus as the only roughage

Tropical Animal Health and Production - This study examined rumen fermentation, histological, blood, and urinary characteristics as well as ammoniacal nitrogen concentration, pH, nitrogen balance,...