19 research outputs found

    The Effect of Soil Texture on the Conversion Factor of 1:5 Soil/Water Extract Electrical Conductivity (EC1:5) to Soil Saturated Paste Extract Electrical Conductivity (ECe)

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    The electrical conductivity of soil saturated paste extract (ECe) is used as an indicator for estimating soil salinity. This method is time consuming and laborious and therefore, easier and faster methods are usually used with different soil/water ratios, such as 1:5 (EC1:5), for estimating the ECe. Usually, the relationship between ECe and EC1:5 is described by a simple linear empirical equation. The value of the conversion factor (CF) of EC1:5 to ECe is affected by the particular characteristics of the soil, such as its texture. The objective of this study is to investigate models that allow the inclusion of soil texture in the calculation of the CF, in order to improve the prediction of the ECe. A total of 148 soil samples with different soil texture and salinity levels were selected from three regions of Greece, and ECe, EC1:5, as well as clay and sand contents were determined. The results show that the CF can be estimated from an equation which incorporates the clay and sand contents through the soil saturation percentage (SP) and can give a fairly good prediction of ECe from EC1:5 (R2 = 0.9887 and RMSE = 1.39 dSm−1)

    Saturated Hydraulic Conductivity Measurements in a Loam Soil Covered by Native Vegetation: Spatial and Temporal Variability in the Upper Soil Layer

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    Saturated hydraulic conductivity (Ks) of soil, especially of the upper soil layer, is a basic parameter for modeling water infiltration and solute transport in the soil. In the present study, spatial and temporal variability of Ks in the upper soil layer of a loam soil, which was covered by native vegetation for 20 years and had not undergone any cultivation treatment, is investigated. Saturated hydraulic conductivity of 76 undisturbed soil samples, taken twice a year at the dry (37 soil samples) and rainy periods (39 soil samples), was measured using a constant head method. The study reveals that Ks values exhibit significant spatial variability over the two time periods of measurement and follow a lognormal distribution with a coefficient of variation greater than 70%. On the contrary, there was no statistically significant seasonal variability of Ks between summer (dry period) and winter (rainy period) sampling (p > 0.05), and, therefore, there was no significant temporal variability of Ks. The outcome of this study indicated that hydrological models have to include more process understanding in terms of natural variability

    The Effect of Soil Texture on the Conversion Factor of 1:5 Soil/Water Extract Electrical Conductivity (<i>EC</i><sub>1:5</sub>) to Soil Saturated Paste Extract Electrical Conductivity (<i>EC<sub>e</sub></i>)

    No full text
    The electrical conductivity of soil saturated paste extract (ECe) is used as an indicator for estimating soil salinity. This method is time consuming and laborious and therefore, easier and faster methods are usually used with different soil/water ratios, such as 1:5 (EC1:5), for estimating the ECe. Usually, the relationship between ECe and EC1:5 is described by a simple linear empirical equation. The value of the conversion factor (CF) of EC1:5 to ECe is affected by the particular characteristics of the soil, such as its texture. The objective of this study is to investigate models that allow the inclusion of soil texture in the calculation of the CF, in order to improve the prediction of the ECe. A total of 148 soil samples with different soil texture and salinity levels were selected from three regions of Greece, and ECe, EC1:5, as well as clay and sand contents were determined. The results show that the CF can be estimated from an equation which incorporates the clay and sand contents through the soil saturation percentage (SP) and can give a fairly good prediction of ECe from EC1:5 (R2 = 0.9887 and RMSE = 1.39 dSm−1)

    The effect of whole sesame seeds on milk chemical composition, fatty acid profile and antioxidant status in goats

    No full text
    Whole sesame seeds (WSS), although rich in linoleic acid, have not been studied for their impact on the milk fatty acid (FA) profile. Twenty-four goats were divided into three homogeneous subgroups. A control (CON) group and treated groups, in which WSS were incorporated in the concentrates of the CON at 5% (WSS5) and 10% (WSS10), respectively, by partial substitution of both soybean meal and corn grain, were evaluated. Significant increases in the milk fat and total solids contents of goats fed the WSS10 diet compared with the CON were found. In the milk of WSS10-fed goats, the proportions of long-chain fatty acids, monounsaturated fatty acids and unsaturated fatty acids (UFAs) were increased, while those of medium-chain fatty acids and saturated fatty acids (SFAs) were decreased compared with those of the CON group. Significant decreases in the proportions of short-chain fatty acids, in the SFA/UFA ratio and in the atherogenicity index value in milk of treated goats were observed. The proportions of C15:0 and C17:0 FAs in the blood plasma of WSS10-fed animals compared with CON-fed animals were reduced significantly. Superoxide dismutase and catalase activities increased significantly in the blood plasma of WSS10-fed goats compared with CON-fed goats. Additionally, in the treated goats, the protein carbonyls (PC) in blood plasma and both PC and malondialdehyde contents in milk declined significantly. A significant enhancement in the total antioxidant capacity [measured by the ferric reducing ability of plasma (FRAP)] in the milk of WSS10-fed goats compared with the CON was found. Similarly, an increase in the FRAP value of milk of WSS5-fed goats compared with CON-fed goats was observed. In conclusion, the highest inclusion level of WSS (WSS10) in goat diets improves the FA profile and the oxidative stability of milk and improves the organism's antioxidant status

    Assessment of the Microbiological Quality and Biochemical Parameters of Traditional Hard Xinotyri Cheese Made from Raw or Pasteurized Goat Milk

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    Traditional hard Xinotyri cheese was manufactured using raw or pasteurized goat milk, without starter cultures, and the changes in microbiological and biochemical characteristics were studied during ripening and storage. Mesophilic lactic acid bacteria (LAB) predominated (>8.5 log CFU/g) in freshly fermented Xinotyri cheeses (pH 4.5–4.6), regardless of milk pasteurization. Enterobacteria, pseudomonads and staphylococci were suppressed below 6 and 4–5 log CFU/g in fresh cheeses from raw and pasteurized milk, respectively. Salmonella and Listeria spp. were absent in 25 g cheese samples. Coagulase-positive staphylococci exceeded the 5-log safety threshold in fresh raw milk cheeses, which also had 10-fold higher levels of enterococci than pasteurized milk cheeses. Non-LAB groups declined <100 CFU/g, whereas yeasts increased to 5–6 log CFU/g in both cheeses during ripening. Milk pasteurization affected the protein, fat, ash, moisture, nitrogen fractions, total free fatty acids and total free amino acids content of cheeses. Primary proteolysis, detectable by urea-PAGE, was more intense in raw milk cheeses than in pasteurized milk cheeses. However, the hydrophilic and hydrophobic peptides and their ratio in the water-soluble fraction were similar in both cheeses. Cheeses discriminated clearly according to the milk kind (raw, pasteurized) and the stage of ripening, based on the examined biochemical characteristics

    Assessment of the Microbiological Quality and Biochemical Parameters of Traditional Hard Xinotyri Cheese Made from Raw or Pasteurized Goat Milk

    No full text
    Traditional hard Xinotyri cheese was manufactured using raw or pasteurized goat milk, without starter cultures, and the changes in microbiological and biochemical characteristics were studied during ripening and storage. Mesophilic lactic acid bacteria (LAB) predominated (&gt;8.5 log CFU/g) in freshly fermented Xinotyri cheeses (pH 4.5&ndash;4.6), regardless of milk pasteurization. Enterobacteria, pseudomonads and staphylococci were suppressed below 6 and 4&ndash;5 log CFU/g in fresh cheeses from raw and pasteurized milk, respectively. Salmonella and Listeria spp. were absent in 25 g cheese samples. Coagulase-positive staphylococci exceeded the 5-log safety threshold in fresh raw milk cheeses, which also had 10-fold higher levels of enterococci than pasteurized milk cheeses. Non-LAB groups declined &lt;100 CFU/g, whereas yeasts increased to 5&ndash;6 log CFU/g in both cheeses during ripening. Milk pasteurization affected the protein, fat, ash, moisture, nitrogen fractions, total free fatty acids and total free amino acids content of cheeses. Primary proteolysis, detectable by urea-PAGE, was more intense in raw milk cheeses than in pasteurized milk cheeses. However, the hydrophilic and hydrophobic peptides and their ratio in the water-soluble fraction were similar in both cheeses. Cheeses discriminated clearly according to the milk kind (raw, pasteurized) and the stage of ripening, based on the examined biochemical characteristics

    The Effect of Forage-to-Concentrate Ratio on Schizochytrium spp.-Supplemented Goats: Modifying Rumen Microbiota

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    The inclusion of feed additives and the implementation of various nutritional strategies are studied to modify the rumen microbiome and consequently its function. Nevertheless, rumen enzymatic activity and its intermediate products are not always matched with the microbiome structure. To further elucidate such differences a two-phase trial using twenty-two dairy goats was carried out. During the first phase, both groups (20HF n = 11; high forage and 20HG n = 11; high grain) were supplemented with 20 g Schizochytrium spp./goat/day. The 20HF group consumed a diet with a forage:concentrate (F:C) ratio of 60:40 and the 20HG-diet consisted of a F:C = 40:60. In the second phase, the supplementation level of Schizochytrium spp. was increased to 40 g/day/goat while the F:C ratio between the two groups were remained identical (40HF n = 11; high forage and 40HG n = 11; high grain). By utilizing a next-generation sequencing technology, we monitored that the high microalgae inclusion level and foremost in combination with a high grains diet increased the unmapped bacteria within the rumen. Bacteroidetes and Prevotella brevis were increased in the 40HG -fed goats as observed by using a qPCR platform. Additionally, methanogens and Methanomassiliicoccales were increased in high microalgae-fed goats, while Methanobrevibacter and Methanobacteriales were decreased. Fibrolytic bacteria were decreased in high microalgae-fed goats, while cellulolytic activity was increased. Ammonia was decreased in high grains-fed goats, while docosapentaenoic and docosahexaenoic acids showed a lower degradation rate in the rumen of high forage-fed goats. The alteration of the F:C ratio in goats supplemented with Schizochytrium spp. levels modified both ruminal microbiota and enzymatic activity. However, there was no significant consistency in the relations between them

    The Impact of Whole Sesame Seeds on the Expression of Key-Genes Involved in the Innate Immunity of Dairy Goats

    No full text
    Whole sesame seeds (WSS) are rich in both linoleic acid (LA) and lignans. However, their impact on the innate immunity of goats is not well studied. Twenty-four goats were divided into three homogeneous sub-groups; comprise one control (CON) and two treated (WWS5 and WWS10). In the treated groups, WSS were incorporated in the concentrates of the CON at 5 (WSS5) and 10% (WSS10) respectively, by partial substitution of both soybean meal and corn grain. The expression levels of MAPK1, IL6, TRIF, IFNG, TRAF3, and JUND genes in the neutrophils of WSS10 fed goats were reduced significantly compared with the CON. The same was found for the expression levels of IFNG and TRAF3 genes in the neutrophils of WSS5 fed goats. Both treated groups primarily affected the MYD88-independent pathway. The dietary supplementation of goats with WSS might be a good nutritional strategy to improve their innate immunity

    Influence of dietary sesame meal, vitamin E and selenium supplementation on milk production, composition, and fatty acid profile in dairy goats

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    Although sesame oil meal is rich in linoleic acid, and both selenium (Se) and vitamin E (VitE) protect prone-unsaturated fatty acids (UFA) from oxidation, their influence on goats’ milk fatty acids (FAs) profile have not been studied. Thus, thirty dairy goats were divided into five groups and fed with alfalfa hay and concentrates. Two types of concentrates were used; one for the control (CON) and another for the treated groups. In the concentrate of the treated groups which contained sesame oil meal, apart from the quantities of VitE and Se included in the trace mineral-vitamin premix, either no extra VitE and Se (SOM) or extra 60 mg of VitE/Kg of concentrate (SOME), or 0.1 mg organic Se/Kg of concentrate (SOMSe) or its combination (60 mg of VitE and 0.1 mg organic Se/Kg of concentrate) (SOMESe) were incorporated. In blood plasma, the proportion of C14:0 reduced significantly in the SOME-fed goats compared with CON-fed goats while that of C16:0 reduced significantly in those goats fed the SOM, SOMSe, SOMESe diets. The proportions of medium-chain FAs (MCFA) and saturated FAs (SFA), and the atherogenicity index value reduced significantly in the milk of treated animals. Significant was also the decline in the SFA/UFA ratio in the milk of goats fed with the SOM, SOME and SOMESe diets. On the contrary, the proportions of long-chain FAs in the milk of SOM and SOMESe fed goats increased significantly. A significant increase in the proportions of UFA in the milk of SOME and SOMESe-fed goats and in the proportions of MUFA in those goats fed the SOM, SOME and SOMESe diets was found. In conclusion, the SOMESe diet can be considered as the most effective nutritional strategy to affect positively the goats’ milk FAs profile since the sharpest modifications in the aforementioned FAs were observed with this dietary treatment
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