Determination of critical nitrogen dilution curve based on leaf area index for winter wheat in the Guanzhong Plain,Northwest China

Excessive use of nitrogen(N) fertilizers in agricultural systems increases the cost of production and risk of environmental pollution. Therefore, determination of optimum N requirements for plant growth is necessary. Previous studies mostly established critical N dilution curves based on aboveground dry matter(DM) or leaf dry matter(LDM) and stem dry matter(SDM), to diagnose the N nutrition status of the whole plant. As these methods are time consuming, we investigated the more rapidly determined leaf area index(LAI) method to establish the critical nitrogen(N_c) dilution curve, and the curve was used to diagnose plant N status for winter wheat in Guanzhong Plain in Northwest China. Field experiments were conducted using four N fertilization levels(0, 105, 210 and 315 kg ha-1) applied to six wheat cultivars in the 2013–2014 and 2014–2015 growing seasons. LAI, DM, plant N concentration(PNC) and grain yield were determined. Data points from four cultivars were used for establishing the N_c curve and data points from the remaining two cultivars were used for validating the curve. The N_c dilution curve was validated for N-limiting and non-N-limiting growth conditions and there was good agreement between estimated and observed values. The N nutrition index(NNI) ranged from 0.41 to 1.25 and the accumulated plant N deficit(N_(and)) ranged from 60.38 to –17.92 kg ha~(-1) during the growing season. The relative grain yield was significantly affected by NNI and was adequately described with a parabolic function. The N_c curve based on LAI can be adopted as an alternative and more rapid approach to diagnose plant N status to support N fertilization decisions during the vegetative growth of winter wheat in Guanzhong Plain in Northwest China.     

Chronic diarrhea associated with intestinal anomalies in a six-year-old dog.

A 6-year-old mixed-breed dog was referred because of chronic diarrhea, which had begun after antibiotic treatment for pulmonary disease. Intestinal bacterial overgrowth was presumptively diagnosed on the basis of intestinal mucosal cytologic examination and low serum cobalamin concentration. When the diarrhea did not respond to treatment, contrast radiography was performed and a short small intestine was found. The diarrhea could not be managed by medical treatment, and the dog was euthanatized. Necropsy revealed 2 blind intestinal pouches attached to a 46-cm length of small intestine connecting the stomach and colon. The dog's deteriorating condition was attributable to necrosis and rupture of 1 of the pouches.     

Estimation of the relative bioavailability of copper sources in chicks fed on conventional dietary amounts

1. Tissue accumulation of Cu from dietary additions of 0, 5, 10, or 20 mg/kg Cu as reagent grade Cu acetate and feed grade Cu carbonate was determined in day‐old chicks fed on conventional maize‐soyabean meal starter diets (5.41 mg/kg Cu as‐fed basis) for 3 weeks.

2. Average daily food intake, daily weight gain and food conversion were similar among treatments.

3. There were linear increases in plasma and liver Cu concentrations (P< 0.01) as dietary Cu increased.

4. Bioavailability of Cu as carbonate was 0.66 that of Cu in the acetate based on the multiple regression slope ratio of liver Cu concentration on added dietary Cu. Although responses for the two Cu sources did not differ significantly, the relative bioavailability of the Cu carbonate was similar (0.66 vs 0.68) to that obtained in an earlier study (Ledoux et al., 1991) with greater dietary Cu contents (150, 300 and 450 mg/kg) in which the slopes of the equations representing the two sources differed (P<0.05).     

Diagnostic imaging of oronasal fistulas in a dachshund

Oronasal fistula development is described anecdotally as a common disease process in the dachshund but little is known about its imaging appearance. This case report describes the clinical presentation, computed tomography (CT) characterisation, dental radiograph confirmation and treatment of bilateral oronasal fistulas in a 14‐year‐old dachshund.     

Efficacy of famotidine for the prevention of exercise-induced gastritis in racing Alaskan sled dogs

BACKGROUND: Omeprazole reduces the severity of exercise-induced gastritis but not the prevalence of gastric lesions in sled dogs. The frequent feeding of sled dogs during competition likely results in decreased absorption of omeprazole and, thereby, decreased efficacy. HYPOTHESIS: Famotidine, a histamine-2 blocker with good bioavailability in the presence of food, would reduce the incidence and severity of exercise-induced gastric disease in sled dogs. ANIMALS: Sixteen fit Alaskan sled dogs (4 female, 12 male, all intact, age 2-6 years). METHODS: Dogs were randomly assigned to treatment (22 mg famotidine PO q24h) or control groups (n = 8 per group). Famotidine was administered with a meal to the treatment group once daily for 7 days before a challenge and once during exercise. Control dogs were fed an identical diet as the principal group. The 16 dog team completed a 100-mile exercise challenge in 18 hours. A gastroscopy was performed 24 hours after the challenge. The appearance of the mucosa was scored by an individual by using a scoring system. RESULTS: Treatment with famotidine significantly reduced the severity score compared with control (P = .0004). No adverse effects of treatment were reported. CONCLUSIONS AND CLINICAL RELEVANCE: Famotidine is effective in reducing the severity of exercise-induced gastric disease in racing Alaskan sled dogs, with minimal to no adverse effects, and may be recommended for prophylactic use in short distance races.     

Gas-liquid chromatographic-mass spectrometric determination of alpha- and beta-naphthylamines in FD&C Red No. 2 (amaranth)

A method is described for the simultaneous quantitation of trace amounts of alpha- (alpha-NA) and beta-naphthylamines (beta-NA) with detectability in the 0.1 ppb range and sensitivity of 50 picomoles in certified food grade amaranth (FD&C Red No. 2; C.I. Food Red 9; CI 16185). The amaranth sample is extracted with benzene, and the evoporated residue is derivatized with perfluorooctanoic anhydride. The resulting derivatives are separated by gas-liquid chromatography and identified and quantitated by mass spectrometric monitoring of the m/e at 539.04. The method was used for quantitation of alpha-NA and beta-NA in randomly chosen samples of amaranth. Of 11 samples from different manufacturers, 5 were free of the beta-isomer; the remaining samples contained up to 1.2 ppb beta-NA. The concentration of alpha-NA ranged from no detectable amount to 970 ppb; the majority of the samples contained less than 7 ppb.     

Gas-liquid chromatographic determination of monosodium glutamate in soups and soup bases.

A method is given for determining monosodium glutamate (MSG) in soups and soup bases by gas-liquid chromatography (GLC) of the trimethylsilyl ether derivative of glutamic acid. This method compared favorably with existing methods including GLC of the trifluoroacetate (TFA)/butyl ester derivative, and analysis on an amino acid analyzer. In addition, some samples were analyzed by GLC/mass spectrometry. The MSG content of various products ranged from approximately 0.2% in some condensed soups to 13.1% on bouillon cubes. The method, which can detect as little as 0.05%, requires only a 10 min single step derivatization at room temperature and is preferred to the TFA/butyl ester technique.