Consumption of oxidized oil increases oxidative stress in broilers and affects the quality of breast meat

A total of 120 4-week-old broiler chickens were allotted to 12 pens and fed one of three diets including control, oxidized diet (5% oxidized oil), or antioxidant-added diet (500 IU vitamin E) for 2 weeks. Blood samples were collected at the end of feeding trial, and breast muscles were sampled immediately after slaughter. Breast meats were also collected 24 h after slaughter and used for meat quality measurements. Oxidative stress in blood, lipid and protein oxidation, and sarcoplasmic reticulum Ca2(+)-ATPase (SERCA) activity of breast muscle were determined. The oxidized diet increased oxidative stress in blood and increased carbonyl content in breast meat compared with the other two dietary treatments (P < 0.05). Lipid oxidation of breast muscles with the antioxidant-supplemented diet was lower than that with the oxidized and control diet groups (P < 0.05). Meat from birds fed the oxidized diet showed higher drip loss after 1 and 3 days of storage and greater 0-1 h post-mortem pH decline (P < 0.05). Significant differences in specific SERCA activity in breast muscles from birds fed control and oxidized diets (P < 0.05) were detected. This suggested that dietary oxidized oil induced oxidative stress in live birds and increased lipid and protein oxidation in breast muscle. Decrease in SERCA activity in breast muscles due to oxidative stress in live animals accelerated post-mortem glycolysis, which sped the pH drop after slaughter and increased drip loss, indicating that oxidation of diet can cause PSE-like (pale, soft, and exudative) conditions in broiler breast muscles.     

Impact of housing nursery pigs according to body weight on the onset of feed intake,aggressive behavior,and growth performance

Tropical Animal Health and Production - Housing nursery pigs according to body weight is an observed common practice in production systems and, supposedly, improves growth performance and reduces...     

Variations in annual precipitation and selenium accumulation by Milk‐Vetch

Four Se accumulators and two non‐accumulator plants were examined for their Se content in wet and dry years. No significant change in Se quantity was noted in the non‐accumulators in relation to variations in annual precipitation. However, the concentration of Se found in accumulator plants is significantly higher in wet years than in dry ones. Furthermore, in wet years there is a higher percentage of water soluble Se in these plants than in dry ones. The soils supporting these plants were also examined for their Se content. In dry years these soils contain more water soluble Se than in wet ones but, in dry years, this form of Se is less available due to the lack of available moisture. High precipitation may tend to reduce absorption of Se by plants by diluting the water soluble Se present in the soil solution, but it is clear that it also promotes absorption of Se by encouraging vigorous growth of these accumulator plants.     

Aluminum tolerance in maize: Minimizing pH changes in screening solutions 1

Preliminary screening of maize (Zea mays L.) genotypes for aluminum (Al) tolerance in nutrient solutions over a 12‐day growth period showed greater plant‐induced pH changes in solutions without Al than in solutions containing Al. Such pH changes may alter the specific effect of Al on relative root length (length in Al‐containing solution/length in 0 Al solution) commonly used as an index to rank genotypes with respect to Al tolerance. The objective of this study was to examine several screening methods for identifying Al‐tolerant maize genotypes, and to identify those procedures which resulted in minimal pH fluctuations during the course of screening. The following methods of controlling pH in nutrient solutions were compared: (i) 12‐day exposure to 0 or 5 mg Al/L in nutrient solutions (a) with or (b) without daily pH adjustment or (c) with different NO₃ ^‐/NH₄ ⁺ ratios, and (ii) 2‐day exposure to 0, 5, 10, 25 or 40 mg Al/L treatment solutions followed by a 3‐day recovery period in solutions with an initial pH at (a) 4.6 or (b) 4.0. In the 12‐day experiments, daily pH adjustment to 4.6 did not eliminate large pH fluctuations in the control (0 Al) solutions, and it substantially decreased the soluble Al concentration in the Al‐treatment solution. Varying the ratio of NO₃ ^‐ to NH₄ ⁺ did not eliminate large pH fluctuations. Exposing the seedlings for 2 days to Al solutions at pH 4.6 resulted in large pH differences between 0 Al and Al‐containing solutions and in precipitation of large amounts of Al. In contrast, the 2‐day procedure using solutions with an initial pH at 4.0 was more satisfactory in that the pH was maintained between 4.0 and 3.7 in all solutions, and Al precipitation was minimized. When the 2‐day method at pH 4.0 was used to screen the genotypes, PDMR3 had consistently higher relative root lengths in Al‐containing solutions than did Kalimpos, IPB Varl, UPCA Varl and Trinidad Grp1&2.     

Effects of low root temperature on sap flow rate,soluble carbohydrates,nitrate contents and on cytokinin and gibberellin levels in root xylem exudate of sand‐grown tomato

Tomato (Lycopersicon esculuntum Mill.) grown in open fields in dry land areas or in non‐controlled greenhouses are subjected to substantial daily changes in root temperature. In the field, root‐zone temperatures fluctuate both diurnally and during the growing season. The purpose of this study was to monitor root‐zone temperature effects on tomato initial growth, transpiration, sap flow rate, leaf and air temperatures differences, nitrate accumulation, total nitrogen, and soluble carbohydrates in the shoot and roots as well as levels of endogenous cytokinins and gibberellins in xylem exudate. Tomato seedlings were grown in three growth cabinets with variable control of root temperatures. Three day/night root temperature regimes (12/12, 16/8 and 20/20°C) were employed. Low day root temperatures of 12 and 16°C reduced shoot dry weight by 47 and 26%, root dry weight by 36 and 14%, shoot nitrate by 79 and 50%, root nitrate by 49 and 16%, levels of cytokinins in root xylem exudate by 27 and 13% and gibberellins by 65 and 23%, in relation to the respective values of 20°C day root temperature. Soluble carbohydrates in the shoot and roots were increased significantly (18 and 111%) by 12°C root temperature. The main effects of low root temperatures on shoot growth stem from slow upward transport of plant hormones and nitrate rather than reduction in their rate of biosynthesis or entry to the root, respectively.     

Nitrogen supply determines responses of yield and biomass partitioning of perennial ryegrass to elevated atmospheric carbon dioxide concentrations

Perennial ryegrass (Lolium perenne L. cv. Parcour) grown at eight levels of nitrogen (N) fertilization (0–765 mg/pot) was exposed to ambient (390 ppm) and elevated (690 ppm) carbon dioxide (CO₂) concentrations for 83 days. Plants were cut three times and dry matter yields determined for each harvest. At final harvest, dry weight of root and stubble biomass was determined, as N concentrations of all plant fractions were determined. Carbon dioxide enrichment effects on yield and total plant biomass increased with increasing N fertilization. The weaker CO₂‐related yield enhancement at low N supply was due to the plants inability to increase tiller number. Root fraction of total plant biomass at final harvest was increased by high CO₂ and decreased by N supply. Root biomass was significantly increased by CO₂ enrichment and for both CO₂ treatments the N supply for maximum root mass coincided with the N supply for reaching maximum total plant biomass. A significant correlation between root fraction of total plant dry matter and N concentration of total plant biomass, which was not changed by CO₂ enrichment, indicates that biomass partitioning between shoot and root is controlled by the internal N status of the plant.     

Performance of cowpea cultivars when grown as an intercrop with maize of contrasting maturities

A field trial was conducted during the rainy seasons of 2008 and 2009 at Samaru in northern Guinea savannah of Nigeria to determine the performance of semi-determinate and indeterminate cowpea cultivars intercropped with extra early, early and late maize cultivars. The trial was laid out in a randomized complete block design (RCBD) having treatments arranged as a split-plot factorial. Transmitted radiation was reduced by 49–63% due to shading by the maize plants. Similarly, intercropping cowpea with maize reduced intercepted radiation, fodder yield and grain yield of cowpea by 59–70%, 39–51% and 45–62%, respectively. Intercepted radiation and yields of intercropped cowpea were lower for late maize which maintained high leaf area over a longer period of time. This is supported by the higher plant height, higher leaf area index (LAI) and reduced transmitted radiation recorded in late maize compared with extra early and early maize. Extra early and early maize were less competitive with cowpea because of shorter period of association in addition to permitting higher radiation. Crop value of maize plus cowpea was higher than that of sole cowpea ($2616.8 vs. $1218.7 ha^?1) because higher combined yield was achieved by a more efficient use of resources in the intercrop. Therefore, cowpea cultivar may be intercropped with extra early maize.     

Leaching of potassium,magnesium, manganese and iron in relation to porosity of tilled and orchard loamy soil

Abstract

The aim of this study was to examine the leaching of potassium, magnesium, manganese and iron in tilled and orchard silty loam soil. The experimental treatments were: conventionally tilled field (CT) with main tillage operations including pre-plough (10 cm)+harrowing followed by mouldboard ploughing to 20 cm depth, and a 35-year-old apple orchard (OR) with a permanent sward. Leaching of the cations was determined in soil columns of undisturbed structure, 21.5 cm diameter and 20 cm height, from a depth of 0–20 cm. All the columns were subjected to spray irrigation at a level of 1110 ml (30 mm), and leachate in 50-ml increments was collected. Concentration of the cations in the leachate was determined using a spectrophotometer ICP-AS. Pore size distribution data showed that the volume of pores >20 µm under CT was greater at a depth of 0–10 cm and lower in the 10–20 cm soil layer under OR, and the reverse was true with respect to pores <6 µm. At each 50-ml leachate, concentration of all the cations was greater under CT than OR. In most leachates the differences were more pronounced for potassium and magnesium than iron and manganese. Percolation of the leachate was considerably faster in orchard than tilled soil.     

Characterization of stem rust resistance in old tetraploid wheat landraces from the Watkins collection

Stem rust is one of the important diseases of tetraploid wheats worldwide. One hundred and five landraces from the Watkins collection were assessed for seedling and adult plant stem rust response variation. Seedling resistance genes Sr8a, Sr8b, Sr9e, Sr9g, Sr12, Sr13, Sr17 and Sr23 were postulated in 28 genotypes using Australian and Indian Puccinia graminis f. sp. tritici pathotypes. Four genotypes possessed either uncharacterized seedling stem rust resistance gene(s) or combinations of known stem rust resistance genes with compensating avirulences among pathotypes used. Adult plant stem rust response assessments were made on 73 seedling susceptible genotypes in Australia and Ethiopia. Adult plant stem rust responses varied from 1 (very resistant) to 7 (moderately susceptible) on a 1–9 scale. The Ethiopian nursery was exposed to Ug99 (TTKSK) and JRCQC (virulent on Sr9e and Sr13). Some genotypes that exhibited high responses in Australia were scored low in Ethiopia. These results demonstrated the effectiveness of some resistance gene(s) that were ineffective in Australia. The opposite trend was also noted. Over 50 % genotypes exhibited commercially acceptable rust responses varying between 2 and 5 across sites and years. Genotyping with the Sr2-linked molecular marker csSr2 did not detect Sr2 in any of the genotypes. The marker gwm533 however detected the presence of Sr2 in eight genotypes. Stem rust resistant genotypes that carried varying levels of APR could carry new genes. Genetic analysis and deployment of these uncharacterized sources of seedling and APR in new cultivars will ensure durable stem rust control through increased diversity.     

BORON DEFICIENCY IN RAINFED WHEAT IN PAKISTAN: INCIDENCE,SPATIAL VARIABILITY AND MANAGEMENT STRATEGIES

Boron (B) deficiency is potentially an important nutrient constraint in calcareous soils. We determined B deficiency incidence and spatial distribution in rainfed wheat (Triticum aestivum L.) in 1.82 Mha Pothohar plateau in Pakistan, its relationship with soil types, crop responses to B, and internal B requirement and B fertilizer use efficiency of wheat. Plant and soil analyses indicated deficiency in 64% of the 61 sampled fields; geostatistics-aided contour maps delineated B deficient areas. In rainfed field experiments, B use increased wheat yields up to 11%. Fertilizer requirement was 1.2 kg B ha^?1; critical B concentration (mg kg^?1) ranges were: young whole shoots, 4–6; flag leaves, 5–7. Boron uptake by wheat was 0.14–0.58% of applied dosage, leaving substantial residual impact. Highly cost-effective B use or B-efficient genotype adoption can enhance wheat productivity and grower-income. Such effective nutrient assessment and management approaches can be beneficially adopted elsewhere as well.