Characterization of clay and fine silt fractions of forest soils by standardized K/Ca sorption isotherms

For better comparison of selectivity characteristics of clay and fine silt fractions sorption isotherms standardized on the cation exchange capacity (CEC) are useful. Due to the effect of the CEC on the sorption isotherms, it is necessary to characterize the exchanging substance with regard to different ion selectivities with standardized potassium/calcium‐(K/Ca) sorption isotherms. This procedure helps to complete the knowledge about the mineralogical composition, which is obtained by X‐ray powder diffractometry. A Haplic Luvisol from boulder marl shows distinct differences in its K selectivity both between different particle size fractions and different horizons. This is partly due to the presence of smectites and vermiculites which are differently distributed within the particle size fractions. The increase of K selectivity with increasing particle diameter in the calcareous C horizon can be attributed to the marginal expansion of mica/illite by Ca²⁺ ions. The K selectivity of individual particle size fractions in different horizons of a Gleyic Cambisol from glacial sand shows major similarities. If pedogenic chlorite is formed, no changes in selectivity characteristics can be observed.     

Effects of Agave fructans (<Emphasis Type="Italic">Agave tequilana</Emphasis> Weber var. azul) on Body Fat and Serum Lipids in Obesity

Obesity affects millions of people worldwide, constituting a public health problem associated with premature mortality. Agave fructans decrease fat mass, body and liver weight, and generate satiety in rodents. In the present study the effects of agave fructans on weight control, lipid profile, and physical tolerability were evaluated in obese people. Twenty-eight obese volunteers were randomly divided into two groups. In the first group, 96 mg/bw of agave fructans was administered for 12 weeks; in the second group, maltodextrin as a placebo was administered for 12 weeks. All participants consumed a low-calorie diet of 1500 kcal/day. Anthropometric and biochemical measurements were taken at baseline and at the end of the study. The body mass index (BMI) of the agave fructans treated group was reduced significantly from the baseline to the final measurements. Hip and waist circumferences decreased statistically in both groups. A decrease of 10% in total body fat was observed in the agave fructans treated group, resulting in a statistically significant difference in the final versus baseline measurements between the Agave fructans treated group and the placebo treated group. Triglycerides were reduced significantly in the agave fructans treated group. Glucose values did not change in either group. Agave fructans intake was safe and well tolerated throughout the study. The results showed that the ingestion of agave fructans enhanced the decrease in BMI, the decrease in total body fat, and the decrease in triglycerides in obese individuals who consume a low-calorie diet.     

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.     

Unsaponifiable lipids from haulm and tuber sprouts of potato (Solanum tuberosum L.)

Summary Fractions containing Δ⁵- and Δ⁷-sterols, 4-methyl-sterols, triterpenic alcohols, tocopherols and hydrocarbons were isolated by TLC from petroleum ether extracts of the haulm and tuber sprouts of cv Désirée. Sterol and triterpenic alcohol fractions of unsaponifiable lipids of the haulm and tuber sprouts were found to contain twelve sterols and four triterpenic alcohols, respectively. 24R-4-stigmasten-3-on, Δ⁷, Δ⁷, lanosterol, cycloeucalenol and obtisufoliol have not been identified previously in unsaponifiable lipids from haulm and sprouts. In the hydrocarbon fractions of the haulm extract, C₂₃-to C₃₃-n-parafins, C₁₉-and C₃₁-cyclohexyl hydrocarbons, C₂₂-to C₃₈-olefins and squalene were identified, and in the hydrocarbon fractions of the tuber sprouts C₁₂-to C₂₆-olefins and squalene were identified.     

Influence of sward height, daily timing of concentrate supplementation, and restricted time for grazing on forage utilization by lactating beef cows

To establish the effect of sward height, concentrate feeding time, and restricted time for grazing on forage utilization by grazing cattle, 32 crossbred beef (24 Angus and eight Hereford) cows (632 kg BW) and calves (104 kg BW) were grouped by weight and calving date. They were assigned randomly to two sward height treatments (4 to 8 or 8 to 12 cm), replicated four times. The herbage comprised mainly Kentucky bluegrass, orchardgrass, some forbs, and white clover. The cows were restricted to 12 h/d grazing (0700 to 1900) or unrestricted to 24 h/d grazing and fed a concentrate supplement (4.1 kg DM.cow(-1).d(-1), approximately 0.65% of BW or 33% of total DMI) either at 0700 or 1800. The experiment was repeated over three 15-d periods in May, June/July, and August 2000. The herbage on high sward height pasture was higher (P = 0.06) in NDF and ADF and lower (P < 0.01) in CP than low sward height herbage. For cows restricted to 12 h/d grazing, supplementing at 0700 as opposed 1800 resulted in greater (P = 0.04) forage DMI (8.6 vs. 8.1 kg/d), whereas cows that were unrestricted showed little change (8.2 kg/d at 0700 vs. 8.4 kg/d at 1800). Supplementing at 1800 as opposed to 0700 resulted in greater (P = 0.03) herbage DM digestibility (67.7 vs. 64.5%) for cows on high sward height, whereas cows on low sward height exhibited minimal differences (65.4% at 1800 vs. 66.3% at 0700). Cows restricted to 12 h/d grazing and supplemented at 0700 as opposed to 1800 resulted in greater (P = 0.06) digestible DMI (5.0 vs. 4.7 kg/d), whereas unrestricted cows exhibited the opposite response (4.6 kg/d digestible DMI at 0700 vs. 4.9 kg/d at 1800). Supplementing at 1800 as opposed to 0700 increased the time spent grazing to a greater (P = 0.09) extent for restricted than for unrestricted cows. When forage availability or grazing time was limiting (due to a low forage allowance and restricted access to forage, respectively) supplementing concentrates at 0700 resulted in greater forage utilization and intake rate because of increased forage DMI, DM digestibility, and digestible DMI. However, when forage or grazing time was not limiting, supplementing concentrates at 1800 resulted in greater forage utilization because of increased forage DM digestibility.     

反刍家畜铜中毒的诊断与治疗

绵羊是对铜毒副作用最敏感的畜种。绵羊的铜中毒可分为慢性或急性中毒,取决于给铜的剂量和持续的时间。Boughton等1934年首次报道绵羊的铜中毒。他们证实,喂含铜的矿物质添加剂几周或数月的绵羊,会发生一种快速死亡的急性病,该病与红细胞迅速遭受破坏、突发血色素血症、黄疸和血红蛋白尿有关,患羊在出现危象的几天内死亡。牛铜中毒见于幼犊,当口服丸剂或非肠道给予某种混合物以补铜时多见。在一份报告中,作者推测慢性铜中毒是造成娟珊母牛死亡的原因。还有一些关于奶牛铜中毒的报道。Stogdale注意到在缺铜草地放牧而饲喂添加铜的燕麦的成年…