Soil mixing in the East Anglian fens

Abstract. Experiments were started in 1967 to investigate the effects of soil mixing on fen peat soil. Peaty topsoil was mixed with mineral subsoil to a maximum depth of 80 cm at two sites, one with a clay subsoil, the other sand. Mixing was done on a commercial scale with a range of implements. After initial increases, yields of arable crops on both mixed soils were subsequently similar to those on unmixed soil. Residual herbicide activity was enhanced on mixed soils, and evidence of peat conservation was obtained at one site. The practice has not been taken up commercially because of the high capital cost of mixing and lack of serious problems which had been predicted following peat wastage.     

Effect of dietary n-6-to-n-3 fatty acid ratio on complete blood and total white blood cell counts, and T-cell subpopulations in aged dogs

OBJECTIVE: To determine effect of diets with variable n-6-to-n-3 fatty acid (FA) ratio on CD4+ and CD8+ T-lymphocyte subpopulations, and on results of routine laboratory analyses (CBC and total WBC count, serum biochemical analyses, and urinalysis). ANIMALS: 20 healthy, aged (9.5 to 11.5 years old) female Beagles. PROCEDURE: Dogs were fed 1 of 3 diets that contained 6% fat by weight but differed in amounts of n-6 and n-3 FA. For 11 weeks, 6 dogs were fed a low concentration of n-3 FA (ratio, 31:1), 7 were fed a medium concentration (5.4:1), and 7 were fed a high concentration (1.4:1). Preprandial blood and urine samples were collected before beginning the study and at 8 weeks for evaluation of laboratory variables. Before and at 3, 6, and 8 weeks during the study, blood was drawn for total WBC and lymphocyte counts and for characterization of T-cell subpopulations. At 8 and 10 weeks, dogs were vaccinated with keyhole limpet hemocyanin suspension. Blood was drawn 4 days after each vaccination, and lymphocytes were isolated for flow cytometry. Effects of diet and vaccination on each variable were determined. RESULTS: After vaccination, total lymphocyte count increased and CD4+ T lymphocyte count and the CD4(+)-to-CD8+ ratio decreased in dogs consuming the diet with n-6-to-n-3 FA ratio of 1.4:1. CONCLUSION: Feeding a diet with n-6-to-n-3 FA ratio of 1.4:1 had significant effects on CD4+ T lymphocytes in healthy, aged Beagles after vaccination.     

Effects of serum vitamin E levels on skin vitamin E levels in dogs and cats

Skin problems are common in small animal practice. Oxidative stress, or the imbalance between prooxidants and the body's antioxidant defense system, likely plays a role in the development of skin disease. According to this study, increasing amounts of vitamin E in foods for dogs and cats increases serum and cutaneous concentrations of vitamin E. Based on available scientific data, these increases in vitamin E concentration are likely to be beneficial. However, the relationship between increases in serum and skin vitamin E concentrations and the prevention, development, and treatment of skin disease remains to be elucidated by intervention studies.     

Antioxidants in veterinary nutrition.

Nutritional antioxidants have experienced a surge in research and interest in the past 20 years. this surge may be attributed to the improved methodology for investigation as well as the focus on diseases and aging processes related to oxidative stress that lend themselves to opportunistic outcomes. As such, the field of veterinary nutritional antioxidant research is also beginning to yield some interesting results, albeit, small in number compared with laboratory animals and human beings. Nonetheless, this article updates the practitioner on recent advances in research involving nutritional antioxidant applications in companion animals.     

Comparison of Serum Concentrations of Symmetric Dimethylarginine and Creatinine as Kidney Function Biomarkers in Cats with Chronic Kidney Disease

Background

Symmetric dimethylarginine (SDMA) has been shown to be an accurate and precise biomarker for calculating estimated glomerular filtration rate (GFR) in humans, as well as a more sensitive biomarker than serum creatinine concentration (sCr) for assessing renal dysfunction.

Objectives

The purpose of this retrospective study was to report on the utility of measuring serum SDMA concentrations in cats for detection of chronic kidney disease (CKD) before diagnosis by conventional measurement of sCr.

Animals

Chronic kidney disease cats (n = 21) included those persistently azotemic for ≥3 months (n = 15), nonazotemic cats with GFR >30% decreased from median GFR of normal cats (n = 4), and nonazotemic cats with calcium oxalate kidney stones (n = 2). Healthy geriatric cats (n = 21) were selected from the same colony.

Methods

Symmetric dimethylarginine concentrations (liquid chromatography‐mass spectroscopy) and sCr (enzymatic colorimetry) were determined retrospectively from historical data or banked serum samples in azotemic cats or at the time GFR (iohexol clearance) was measured in nonazotemic cats.

Results

Serum SDMA (r = −0.79) and sCr (r = −0.77) concentrations were significantly correlated to GFR (both P < .0001). Symmetric dimethylarginine became increased before sCr in 17/21 cats (mean, 17.0 months; range, 1.5–48 months). Serum SDMA had higher sensitivity (100%) compared with sCr (17%), but lower specificity (91% versus 100%) and positive predictive value (86% versus 100%).

Conclusion and Clinical Importance

Using serum SDMA as a biomarker for CKD allows earlier detection of CKD in cats compared with sCr, which may be desirable for initiating renoprotective interventions that slow progression of CKD.     

The effect of demand feeding on swimming speed and feeding responses in Atlantic salmon Salmo salar L., gilthead sea bream Sparus aurata L. and European sea bass Dicentrarchus labrax L. in sea cages

Abstract Using underwater cameras, data were collected on the feeding behaviour and swimming speeds of Atlantic salmon Salmo salar L., gilthead sea bream Sparus aurata L. and European sea bass Dicentrarchus labrax L. in sea cages. Comparisons were made between the behaviours of fish fed on demand using interactive feedback systems and those of fish fed under the standard feeding practice of each farm (control). In all three species, swimming speeds were similar before feeding , but they were significantly higher in the control regimes during feeding. When fed on demand, sea bass had reduced swimming speed just before and during feeding compared with that observed during the non‐feeding periods. Higher proportions of feeding fish were observed in the control regime cages than in fish fed on demand for all three species, indicating a greater feeding intensity during meals in the control regimes. This was further supported by observations of an increase in the density of sea bass in the upper water in the control cages during feeding. The results suggest decreased levels of competition between the on demand‐fed fish during feeding, which might be hypothesized to lead to improved growth and production efficiency in aquaculture.     

Selection against the bracting defect of cauliflower

Summary The appearance of bracts through the surface of the cauliflower curd had a heritability estimate of 0.73 ± 0.10 based on the regression of progeny on parent when grown under field conditions. When curds were taken from field grown plants and aseptically cultured, their bracting characteristics were enhanced. It is advocated that a two-tier system of selection, firstly in the field and then in culture, would increase the likelihood of breeding bract free cauliflowers.Also, Department of Biological Sciences, The Polytechnic, Hatfield, Hertfordshire, UK.     

Improved selection against the purple colour defect of cauliflower curds

Summary Purple colourations of the cauliflower curd detract from the commercial value of the crop. Curds were found to develop purple colourations when in aseptic nutrient culture, and this was correlated with their inherent tendencies to form purple curds in the field as revealed by a progeny test. It was advocated that selection against the defect in the field should be supported by assessment in culture.     

Dietary antioxidants and behavioral enrichment enhance neutrophil phagocytosis in geriatric Beagles

The study objective was to determine the effects of feeding food enriched in antioxidants and a program of environmental/cognitive enrichment on selected ex vivo assays of inflammatory and immune cells in healthy geriatric Beagle dogs (n=21). Four groups of dogs were tested using a 2 x 2 factorial design. The 2-year longitudinal study included both nutritional (control food or antioxidant-fortified food) and behavioral (normal level or cognitive enrichment) interventions. Behavior enrichment included increased exercise, environmental enrichment, and a series of learning tasks. Phagocytosis of opsonized latex-coated beads by peripheral blood neutrophils was measured by flow cytometry and found to be significantly increased in dogs receiving both dietary antioxidants and cognitive enrichment. Simultaneous stimulation of cells with Con A and suppression with Dex resulted in decreased lymphocyte proliferation in dogs receiving both dietary antioxidants and cognitive enrichment, compared to dogs receiving dietary antioxidants or cognitive enrichment alone. There were no significant differences between the groups of dogs for percentages of CD4 and CD8 T-lymphocyte subpopulations before or after lymphocyte stimulation with Con A. These results support our hypothesis that both dietary antioxidants and behavioral enrichment enhance host defense mechanisms.     

Fiber but not conjugated linoleic acid influences adiposity in dogs

Feeding obese dogs a high-fiber food with or without added conjugated linoleic acid (CLA) resulted in reduced caloric consumption, reduced body weight, and a 3.3% reduction in body fat, whereas feeding a low-fiber food resulted in a comparable increase in caloric consumption and a 2.4% gain in body fat. The addition of CLA did not significantly affect food intake, energy intake, final lean body percent, change in lean body percent, or final fat percent. These results suggest that the addition of dietary fiber but not CLA to foods may be helpful in the treatment of canine obesity.