CH4 oxidation and N2O emissions at varied soil water-filled pore spaces and headspace CH4 concentrations

Emission of N₂O and CH₄ oxidation rates were measured from soils of contrasting (30-75%) water-filled pore space (WFPS). Oxidation rates of ¹³C-CH₄ were determined after application of 10 μl ¹³C-CH₄ l⁻¹ (10 at. % excess ¹³C) to soil headspace and comparisons made with estimates from changes in net CH₄ emission in these treatments and under ambient CH₄ where no ¹³C-CH₄ had been applied. We found a significant effect of soil WFPS on ¹³C-CH₄ oxidation rates and evidence for oxidation of 2.2 μg ¹³C-CH₄ d⁻¹ occurring in the 75% WFPS soil, which may have been either aerobic oxidation occurring in aerobic microsites in this soil or anaerobic CH₄ oxidation. The lowest ¹³C-CH₄ oxidation rate was measured in the 30% WFPS soil and was attributed to inhibition of methanotroph activity in this dry soil. However, oxidation was lowest in the wetter soils when estimated from changes in concentration of ¹²⁺¹³C-CH₄. Thus, both methanogenesis and CH₄ oxidation may have been occurring simultaneously in these wet soils, indicating the advantage of using a stable isotope approach to determine oxidation rates. Application of ¹³C-CH₄ at 10 μl ¹³C-CH₄ l⁻¹ resulted in more rapid oxidation than under ambient CH₄ conditions, suggesting CH₄ oxidation in this soil was substrate limited, particularly in the wetter soils. Application of and (80 mg N kg soil⁻¹; 9.9 at.% excess ¹⁵N) to different replicates enabled determination of the respective contributions of nitrification and denitrification to N₂O emissions. The highest N₂O emission (119 μg ¹⁴⁺¹⁵N-N₂O kg soil⁻¹ over 72 h) was measured from the 75% WFPS soil and was mostly produced during denitrification (18.1 μg ¹⁵N-N₂O kg soil⁻¹; 90% of ¹⁵N-N₂O from this treatment). Strong negative correlations between ¹⁴⁺¹⁵N-N₂O emissions, denitrified ¹⁵N-N₂O emissions and ¹³C-CH₄ concentrations (r=−0.93 to −0.95, N₂O; r=−0.87 to −0.95, denitrified ¹⁵N-N₂O; P<0.05) suggest a close relationship between CH₄ oxidation and denitrification in our soil, the nature of which requires further investigation.     

Effect of variety and maturation of cheese on supercritical fluid extraction efficiency

Supercritical fluid extraction (SFE) has been utilized by the food industry in many applications to extract, fractionate, and recover compounds from various food matrices. However, little research has been conducted using SFE as an alternative process for producing reduced-fat cheese. Lipids in cheeses may be selectively extracted due to the nonpolar properties of supercritical carbon dioxide (SC-CO2), without leaving residual chemicals as is the case in solvent extraction. The objective of this study was to evaluate the influence on the extraction process due to cheese variety and protein breakdown by age. A Latin square design was utilized to test the extractability of lipids from Parmesan and Cheddar cheeses, aged young (9-10 months) or old (24 months). Extraction took place in a 500 mL SFE vessel using 100 g of grated cheese samples. The SFE parameters of the extraction were 350 bar, 35 degrees C, and supercritical carbon dioxide at a flow rate of 20 g/min for 55 min. Compositional analysis measured all treated samples and controls of total lipids, lipid profiling, total protein, protein/peptide analysis, moisture, ash, and pH. Cheese type was a major variable in fat extraction. The extraction in Cheddar showed an average fat reduction of 53.56% for young cheese, whereas that in old Cheddar was 47.90%. However, young Parmesan was reduced an average of 55.07%, but old Parmesan was reduced at 68.11%, measured on a dry basis. SFE extracted triglycerides and cholesterol, but did not remove phospholipids. This investigation introduces the observations of the effect of Cheddar and Parmesan varieties on SFE, offering data on the important parameters to consider in the design of SFE processes to reduce fat in cheese.     

Causes of natal dispersal and emigration and their effects on harem formation in Misaki feral horses

Misaki feral horses were separated into 2 herds and the difference between dispersal from natal group (natal dispersal) and dispersal from natal area (natal emigration) was studied. The causes of dispersal and emigration and their effects on harem formation were studied 1979-1994. The number of horses ranged from 73 (mature males: 8, mature females: 26, young males: 8, young females: 3, colt foals: 6, filly foals: 10 and geldings: 12) in 1979 and 86 (mature males: 14, mature females: 37, young males: 12, young females: 7, colt foals: 5, filly foals: 7 and geldings: 4) in 1994 when the present study ended. All 29 males which survived to age 4 years and 58 females which survived to age 3 years left their natal or mother groups at age one to 3. Seventeen of 22 dispersing males and 29 of 39 dispersing females left their natal groups around the birth of their siblings and significant correlations were found between natal dispersal and birth of a sibling. The number of emigrating young males correlated negatively and significantly with the total number of young males in another herd and the number of emigrating young females correlated positively and significantly with the total number of young females in the natal herd. All 13 emigrating stallions which survived to age 5 years formed stable harem groups and a significant correlation was found between natal emigration and harem formation. Twenty-three of 35 resident mares formed stable consort relations with harem stallions and a significant correlation was found between residence and formation of stable consort relations.     

Crossbreeding effects for post-weaning growth traits in a project of Spanish V-line with Baladi Red Rabbits in Egypt

A four-year crossing scheme involving Spanish V line (V) and Egyptian Baladi Red (B) rabbits was carried out to produce five genetic groups: V, B, 1/2B1/2V(F₁), (1/2B1/2V)²(F₂), and ((1/2B1/2V)²)². The last genetic group was considered a new line, named APRI. Body weights (BW) and daily gains in weight (DG) from four to twelve weeks were evaluated for 13,383 rabbits produced by 330 sires and 1074 dams. An animal model was used to estimate heritabilities and common litter effects and a generalized least squares procedure was used to estimate direct additive effects, and direct and maternal heterosis.Heritabilities for growth traits were mostly moderate, ranging from 0.075 to 0.240 for BW and from 0.020 to 0.104 for DG. The V line was heavier and had better gains at each weighing than B rabbits. The F₂ and APRI were also lower in most post-weaning growth performance measures than V line rabbits. APRI rabbits were significantly lighter by 39, 26, 46, 64, and 50 g at ages of 4, 6, 8, 10, and 12 weeks, respectively, relative to the purebred V line, while APRI was significantly heavier by 36 and 127 g relative to the B line at 4 and 12 weeks. The V line, in general, had a higher DG than B line. The differences were 3.15, 7.91 and 1.95 g/d at age intervals of 8–10, 10–12 and 4–12 weeks. Differences in direct additive effects between the two lines were in favor of V line rabbits reaching 15.0% (76 g) at 4 weeks and 13.3% (195 g) at 12 weeks. Direct additive effects for DG were significant during most age intervals reaching 35.7% (7.19 g/d) in the interval of 10–12 weeks. All estimates of direct heterosis were positive and ranged from 4.9 to 16.7% for BW and 14.4 to 29.5% for DG, but the estimates for maternal heterosis were, in most cases, significantly negative and ranging from − 4.5 to − 15.2% for BW and from 20.6 to − 36.9% for DG. If the results are confirmed at commercial farms, the APRI line could be reared in heat stress conditions.     

Protein Changes During Various Stages of Breadmaking of Four Spring Wheats: Quantification by Size-Exclusion HPLC

Protein changes for four hard red spring wheat genotypes (Len, Marshall, 215, and Butte 86) were assessed at various stages of breadmaking using a size-exclusion HPLC technique. Breadmaking stages considered were flour, after mixing, before punching, after punching, after fermentation, and after proofing. Quality and functional characteristics of the four wheat genotypes were determined. The three main protein groups isolated by SE-HPLC were further characterized by SDS-PAGE. A direct relationship between polymeric glutenin (peak I of SE-HPLC fractions) in flours and loaf volume was found for the three wheat genotypes with identical high molecular weight glutenin subunit (HMW-GS) composition (2*, 7+9, 5+10) and one line with similar HMW-GS composition (2*, 7+9, 2+12), differing in the Glu-D1 locus. Quantitative changes in the distribution of SDS-soluble proteins fractionated by SE-HPLC were also examined. Peak I proteins (polymeric proteins) from SDS-extractable proteins tend to decrease during breadmaking, while peak III proteins (low molecular weight) tend to increase. Peak II (monomeric proteins, medium molecular weight) did not show a change in quantity during breadmaking. These results seem to indicate that some type of rearrangement took place during the breadmaking process to release proteins of smaller molecular weight.     

Effects of background colour on growth performance,skin pigmentation,physiological condition and innate immune responses of goldfish,Carassius auratus

A study was carried out to investigate the effects of background colour on the growth performance, skin colour, haematology, physiological condition and non‐specific immune responses of goldfish, Carassius auratus. Goldfish were reared in tanks with four different background colours (white, black, blue and red) for 8 weeks. Fish growth performance markedly rose in white background compared with the other treatments. There was no significant difference in haematological parameters or plasma proteins concentrations between treatments. Plasma cortisol of fish reared in red background was significantly higher than that in black and white backgrounds. Plasma antiprotease and lysozyme activities were more than doubled in white and black treatments compared with the red and blue groups. The other immune parameters tested (plasma peroxidase, complement and bactericidal activities) did not significantly change between treatments. Skin carotenoid content and the intensity of fish skin colour extremely diminished in white background. This study revealed that red and blue backgrounds are chronically stressful and immunosuppressive in goldfish. White backgrounds will preferably be used for the culture of goldfish for best fish growth. However, a way to revert the colour loss of goldfish skin reared in white backgrounds remains to be investigated.     

N2O, NH3 and NOx Emissions as a Function of Urea Granule Size and Soil Type Under Aerobic Conditions

We examined the influence of various urea granule sizes (< 2, 7.0, 9.9 and 12.7 mm) applied into a silt loam soil (experiment 1) and soil types (sandy, silt and clay loam) treated with the largest granule (experiment 2) on gaseous N loss (except N₂) at field capacity. The prilled urea (PU) was mixed into the soil whereas the urea granules were point-placed at a 5.0-cm depth. For experiment 1, N₂O emission was enhanced with increasing granule size, ranging from 0.17–0.50% of the added N during the 45-day incubation period. In the case of experiment 2, the sandy loam soil (0.59%) behaved similarly with the silt loam (0.53%) but both showed remarkably lower emissions than were found for the clay loam soil (2.61%). Both nitrification and N₂O emissions were delayed by several days with increasing granule size, and the latter was influenced by mineral N, soil water and pH. By contrast, the NH₃ volatilization decreased with increasing granule size, implying the inhibition of urease activity by urea concentration gradients. Considering both experimental results, the NH₃ loss was highest for the PU-treated (1.73%) and the larger granules regardless of soil type did not emit more than 0.27% of the added N over 22 days, possibly because the high concentrations of either mineral N or NH₄ ⁺ in the soil surface layer (0–2.5 cm) and the high H₊ buffering capacity might regulate the NH₃ emission. Similar to the pattern of NH₃ loss, NO_x emission was noticeably higher for the PU-treated soil (0.97%) than for the larger granule sizes (0.09–0.29%), which were the highest for the sandy and clay loam soils. Positional differences in the concentration of mineral N and nitrification also influenced the NO_x emission. As such, total NH₃ loss was proportional to total NO_x emission, indicating similar influence of soil and environmental conditions on both. Pooled total N₂O, NH₃ and NO_x emission data suggest that the PU-treated soil could induce greater gaseous N loss over larger urea granules, largely in the form of NH₃ and NO_x emissions, whereas a similar increase with the largest granule size was mainly due to the total N₂O flux.     

Analysis and effect of water sources used as diluents on Newcastle disease vaccine efficacy in chickens in the Sudan

Samples of artesian well, shallow well, surface water, tap water, and bottled water were collected from different areas in Khartoum; these were chemically analyzed and used as diluents to vaccinate chicks against Newcastle disease. Immune response in vaccinated chicks, as measured by the hemagglutination inhibition test, was significantly better in birds which received the vaccine diluted in bottled water followed by those vaccinated using tap water. It appears that water with low turbidity and total dissolved solids were the best water for vaccine dilution. The order of preference of water source, according to this study was bottled water, tap water, shallow well water, artesian well water, and finally surface water.