Liquid chromatography and fluorescence detection of vitamin A in animal feeds, finished feeds, and premixes

A simple liquid chromatographic method for vitamin A (retinol) in animal feeds is described. The feed is saponified, diluted to minimize interferences, and extracted into petroleum ether with a single step. The analysis is sensitive and specific with liquid chromatography and a fluorescence detector. The minimum level of detection is 15 ng/mL, which is equivalent to 10,000 units/lb vitamin A. The method includes a stable and reproducible standardization of vitamin A that is used to calibrate standard peak heights in terms of units retinol/mL. Guarantees of 10,000 units/lb up to premix levels can be analyzed with good recoveries and precision.     

Turbidimetric assay for virginiamycin in feeds and premixes

A turbidimetric assay method applicable to virginiamycin at level ranging from 5 g/ton in feeds to 50% in a premix is described. Incubation period is 4 h. Test organism is Streptococcus faecium ATCC 8043. On 6 levels of feed-grade material, the overall mean recovery was 6.75% Standard recovery studies resulted in RSD values ranging from 2.01 to 3.88% and a mean standard recovery of 100%.     

锥栗贮藏过程维生素C的降解速率以及保鲜条件研究

采用试验研究了锥栗贮藏过程中维生素C(维生素C)的降解速率及其保鲜条件。将3个不同品种的锥栗经不同浓度的抑霉唑浸泡，并在3个不同温度(-1～0℃、5℃、10℃)中进行贮藏，测定贮藏中锥栗维生素C的含量的变化。锥栗中维生素C的降解速率与维生素C的浓度成正比，求得降解速率系数k，对其进行非线性拟合，并用极差分析法和方差分析法进行分析研究。试验结果表明，最优的保鲜条件为：温度-1～0℃、品种为长芒、抑霉唑浓度2000 μL/L。     

微晶化对钾长石粉钾素释放的影响

摘要: 利用微晶化设备对钾长石进行机械力活化处理,研究了不同处理时间对钾长石粉颗粒组成、 钾素释放量及生物有效性的影响。结果表明,钾长石经微晶化设备分别加工10 min、 40 min、 120 min和180 min后,微细颗粒（d10 m）组成比例分别达到51.69%、 65.44%、 85.34%和93.93%,比表面积明显增大,衍射峰强度显著减弱,同时钾素的释放量显著提高,其中微晶化处理180 min样品T3效果最好,2 mol/L HNO3和蒸馏水3次提取的钾总量分别为6118.8 mg/kg和2867.8 mg/kg; 4个处理（10 min、 40 min、 120 min和180 min）酸提钾总量分别是蒸馏水提钾总量的2.46、 1.81、 2.19和2.13倍,两种浸提剂提钾总量占钾长石全钾的0.50%~5.73%。微晶化以后钾长石粉中的绝大部分钾素仍以矿物态存在,但其生物有效性显著提高,促进了籽粒苋的生长和钾素积累。     

Effects of acid sulphate on DOC release in mineral soils: the influence of SO42− retention and Al release

Dissolved organic carbon (DOC) in acid‐sensitive upland waters is dominated by allochthonous inputs from organic‐rich soils, yet inter‐site variability in soil DOC release to changes in acidity has received scant attention in spite of the reported differences between locations in surface water DOC trends over the last few decades. In a previous paper, we demonstrated that pH‐related retention of DOC in O horizon soils was influenced by acid‐base status, particularly the exchangeable Al content. In the present paper, we investigate the effect of sulphate additions (0–437 µeq l^?1) on DOC release in the mineral B horizon soils from the same locations. Dissolved organic carbon release decreased with declining pH in all soils, although the shape of the pH‐DOC relationships differed between locations, reflecting the multiple factors controlling DOC mobility. The release of DOC decreased by 32–91% in the treatment with the largest acid input (437 µeq l^?1), with the greatest decreases occurring in soils with very small % base saturation (BS, < 3%) and/or large capacity for sulphate (SO₄^2?) retention (up to 35% of added SO₄^2?). The greatest DOC release occurred in the soil with the largest initial base status (12% BS). These results support our earlier conclusions that differences in acid‐base status between soils alter the sensitivity of DOC release to similar sulphur deposition declines. However, superimposed on this is the capacity of mineral soils to sorb DOC and SO₄^2?, and more work is needed to determine the fate of sorbed DOC under conditions of increasing pH and decreasing SO₄^2?.     

High pressure liquid chromatographic determination of vitamin D3 in livestock feed supplements.

Vitamin D3 is determined in livestock feed supplements by high pressure liquid chromatography (HPLC). Extracts of the samples are quantitated using normal phase chromatography. If interfering co-extractives are present, an aliquot of the extract is injected on the normal phase column, and the fraction corresponding to vitamin D3 is collected. The vitamin fraction is then further cleaned up and separated from interferences by reverse phase chromatography, and quantitated by measuring the ultraviolet absorption at 254 and 280 nm. The method measures actual vitamin D3 content in the presence of pre-vitamin D, tachysterol, isotachysterol, and vitamin A.     

Effects of vitamin E supplementation on lipid peroxidation and color retention of salted calf muscle from a diet rich in polyunsaturated fatty acids.

The color of fresh meat is one of the most important quality criteria of raw muscle foods. This red color is principally due to the presence of oxymyoglobin. The present study was undertaken to examine the effect of a diet rich in polyunsaturated fatty acids (PUFA), the addition of NaCl, and the influence of dietary supplementation with vitamin E on calf muscle oxymyoglobin oxidation (color) and lipid peroxidation. Vitamin E was added to the feed at a concentration of 4000 mg/day for 90 days before slaughter. This diet increased the alpha-tocopherol concentration in muscle membrane from 2.6-2.8 to 6.5-7.0 microg/g of fresh weight. It was found that the diet rich in PUFA and, especially, the addition of NaCl increased muscle lipid peroxidation and oxymyoglobin oxidation as indicated by the contents of thiobarbituric acid-reactive substances and substances that impaired color value readings during storage at 4 degrees C. Both undesirable reactions during storage were controlled very efficiently by the presence of a critically high concentration of alpha-tocopherol in the muscle tissues. The findings concerning the antioxidant activity of alpha-tocopherol in this study form additional evidence of its efficient protection against oxidative reactions during storage of muscle tissues and its potential to maintain a high nutritional value in them.     

Quality changes and nutrient retention in fresh-cut versus whole fruits during storage

The influences of processing and storage on the quality indices and nutritional content of fresh-cut fruits were evaluated in comparison to whole fruits stored for the same duration but prepared on the day of sampling. Fresh-cut pineapples, mangoes, cantaloupes, watermelons, strawberries, and kiwifruits and whole fruits were stored for up to 9 days in air at 5 degrees C. The postcutting life based on visual appearance was shorter than 6 days for fresh-cut kiwifruit and shorter than 9 days for fresh-cut pineapple, cantaloupe, and strawberry. On the other hand, fresh-cut watermelon and mango pieces were still marketable after 9 days at 5 degrees C. Losses in vitamin C after 6 days at 5 degrees C were < or = 5% in mango, strawberry, and watermelon pieces, 10% in pineapple pieces, 12% in kiwifruit slices, and 25% in cantaloupe cubes. No losses in carotenoids were found in kiwifruit slices and watermelon cubes, whereas losses in pineapples were the highest at 25% followed by 10-15% in cantaloupe, mango, and strawberry pieces after 6 days at 5 degrees C. No significant losses in total phenolics were found in any of the fresh-cut fruit products tested after 6 days at 5 degrees C. Light exposure promoted browning in pineapple pieces and decreased vitamin C content in kiwifruit slices. Total carotenoids contents decreased in cantaloupe cubes and kiwifruit slices, but increased in mango and watermelon cubes in response to light exposure during storage at 5 degrees C for up to 9 days. There was no effect of exposure to light on the content of phenolics. In general, fresh-cut fruits visually spoil before any significant nutrient loss occurs.     

堆肥含水量与腐熟度对其粉碎度的影响研究

以鸡粪和麦秸为原料，通过堆肥不同腐熟度和不同含水量下粉碎度的测定，表明堆肥含水量是控制粉碎度大小的首要因素，堆肥粉碎度随含水量的增加而降低，两者满足二级动力学方程。粉碎度的临界含水量为20％，含水量低于20％时，粉碎度的变化较小。含水量大于20％时，腐熟度对粉碎度的影响增强。腐熟的堆肥更容易粉碎。粉碎度与GI(发芽指数)、EC、pH值等腐熟度指标并不存在相关关系。但与TOC呈负线性相关，与全N、C/N比呈显著负二次相关。粉碎度与堆肥化学参数：纤维素、半纤维素含量呈负线性相关，与木质素无相关性。     

Liquid chromatographic method for determination of furazolidone in premixes and complete feeds: collaborative study

A liquid chromatographic (LC) method for determining furazolidone in finished feeds and premixes was collaboratively studied. Finished feed sample is extracted with acetone-water (93 + 7) on a Goldfisch apparatus, extracting solvent is removed, and the residual material is dissolved in warm DMF. A solution of tetraethylammonium bromide is added, the fat layer is removed, and the sample is clarified by filtration and injected onto a reverse phase LC system with detection at 365 nm. Premixes, extracted by shaking with DMF and diluted so that the final furazolidone concentration is about 55 micrograms/mL, are chromatographed and detected the same as finished feed samples, using a mobile phase of acetonitrile-2% acetic acid (20 + 80). Ten commercial feed samples were preweighed and supplied to 14 collaborators. The 5 matched pairs were chosen to represent the following allowed levels: 0.0055, 0.022, 0.033, 2.2, and 22%. Two familiarization samples at the 0.0055 and 11% levels were also supplied. Instructions called for a single analysis of each sample. Two results were eliminated by the Dixon test. The coefficients of variation, following treatment by the ranking test, ranged from 2.0 at the 22% level to 6.5 at the 0.0055% level. Calculated F-values are not significant (P greater than 0.01) except for the 0.0055% level samples extracted overnight. This method has been adopted official first action.     

Effects of nonylphenols on soil microbial activity and water retention

The main aim of this study is to analyze the influence of 4-nonylphenol (NP) on soil water retention and biological activity. Two doses of 4-nonylphenol (25 and 50 mg kg⁻¹) were tested in a loam soil with and without peat amendment. In general, one week after the start of the experiment, the soil water content retained at −0.75 MPa of soil suction was 18% higher in the soil amended and its basal respiration (BR) was 15% higher than soil without peat. In contrast, the microbial activity indices (CM: coefficient of mineralization or BR:total organic carbon (TOC) ratio; Cmic:Corg: microbial biomass carbon (MBC):TOC ratio; qCO₂: metabolic quotient or BR:MBC ratio) were higher in the soil without peat, compared to the soil amended with peat. On the other hand, the addition of NP to soil was able to modify soil biological but not physical (water retention, desorption) properties. When soil was amended with peat, MBC was reduced one week after applying NP. In contrast, no effects of NP on MBC were observed in the soil without peat. BR was reduced by 16% one week after applying 50 mg kg⁻¹ of NP to soil with peat, and was increased by 46% one week after applying 25 mg kg⁻¹ of NP to soil without peat. The effects of NP on MBC and BR could be associated more with the adsorption of NP by soil organic matter, while changes in CM or Cmic:Corg ratio were more closely related to changes in soil water retention. The potential toxic effects of NP (high qCO₂ values) were only observed in the absence of peat amendments. Peat addition reduced NP toxic effects on microorganisms.     

Determination of oxytetracycline in premixes and veterinary products by liquid chromatography

A liquid chromatographic method for the assay of oxytetracycline in premixes and veterinary products is described. Premix samples are extracted with acidified methanol, diluted with mobile phase, and filtered before chromatography on a C-8, reverse phase column. The assay method separates oxytetracycline from epioxytetracycline, tetracycline, and chlortetracycline. Total elution time for oxytetracycline is less than 5 min at 1.5 mL/min. Five spiked premix samples each of 2 and 50 g/lb had a coefficient of variation of 3.5 and 4.5% and a mean recovery of 99 and 104%, respectively. The results of premixes and veterinary products assayed by this method compared closely with those of the same assayed by the official AOAC microbiological method.     

Effects of mineral nutrition on tillering of rice

Studies on tillering of the rice plant show that a tiller primordium is always present at each node of the culm (10). Whether the primordllun develops into a tiller depends on such factors as the nutritional status of the plant, the supply of carbohydrates, and the light and temperature conditions (2,3,5,6,7,8,9,11,12,13,14,15,17).     

Effects of excess aluminum on mineral uptake in mycorrhizal sorghum

Soil acidity is often associated with toxic aluminum (Al), and mineral uptake usually decreases in plants grown with excess Al. This study was conducted to evaluate the effects of Al (0, 35, 70, and 105 μM) on Al, phsophorus (P), sulfur (S), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn,) and copper (Cu) uptake in shoots and roots of sorghum [Sorghum bicolor (L.) Moench, cv. SC283] colonized with the vesicular‐arbuscular mycorrhizal (VAM) fungi isolates Glomus intraradices UT143–2 (UT143) and Glomus etunicatum UT316A‐2 (UT316) and grown in sand (pH 4.8). Mycorrhizal (+VAM) plants had higher shoot and root dry matter (DM) than nonmycorrhizal (‐VAM) plants. The VAM treatment had significant effects on shoot concentrations of P, K, Ca, Fe, Mn, and Zn; shoot contents of P, S, K, Ca, Mg, Fe, Mn, Zn, and Cu; root concentrations of P, S, K, Ca, Mn, Zn, and Cu; and root contents of Al, P, S, K, Ca, Mg, Fe, Mn, Zn, and Cu. The VAM effects on nutrient concentrations and contents and DM generally followed the sequence of UT316 > UT143 > ‐VAM. The VAM isolate UT143 particularly enhanced Zn uptake, and both VAM isolates enhanced uptake of P and Cu in shoots and roots, and various other nutrients in shoots or roots.     

Effects of mineral and biofertilizers on barley growth on compacted soil

Abstract

Biofertilizers are an alternative to mineral fertilizers for increasing soil productivity and plant growth in sustainable agriculture. The objective of this study was to evaluate possible effects of three mineral fertilizers and four plant growth promoting rhizobacteria (PGPR) strains as biofertilizer on soil properties and seedling growth of barley (Hordeum vulgare) at three different soil bulk densities, and in three harvest periods. The application treatments included the control (without bacteria inoculation and mineral fertilizers), mineral fertilizers (N, NP and P) and plant growth promoting rhizobacteria species (Bacillus licheniformis RC04, Paenibacillus polymyxa RC05, Pseudomonas putida RC06, and Bacillus OSU-142) in sterilized soil. The PGPR, fungi, seedling growth, soil pH, organic matter content, available P and mineral nitrogen were determined in soil compacted artificially to three bulk density levels (1.1, 1.25 and 1.40 Mg m^?3) at 15, 30, and 45 days of plant harvest. The results showed that all the inoculated bacteria contributed to the amount of mineral nitrogen. Seed inoculation significantly increased the count of bacteria and fungi. Data suggest that seed inoculation of barley with PGPR strains tested increased root weight by 9–12.2%, and shoot weight by 29.7–43.3% compared with control. The N, NP and P application, however, increased root weight up to 18.2, 25.0 and 7.4% and shoot weight by 31.6, 43.4 and 26.4%, respectively. Our data show that PGPR stimulate barley growth and could be used as an alternative to chemical fertilizer. Soil compaction hampers the beneficial plant growth promoting properties of PGPR and should be avoided.