Genotypic variation for root traits of maize (Zea mays L.) from the Purhepecha Plateau under contrasting phosphorus availability

Phosphorus (P) deficiency is a major constraint for maize production in many low-input agroecosystems. This study was conducted to evaluate genotypic variation in both root (root architecture and morphology, including root hairs) and plant growth traits associated with the adaptation of maize landraces to a P-deficient Andisol in two locations in the Central Mexican highlands. Two hundred and forty-two accessions from the Purhepecha Plateau, Michoacan were grown in Ponzomaran with low (23 kg P₂O₅ ha⁻¹) and high (97 kg P₂O₅ ha⁻¹) P fertilization under rain-fed field conditions, and subsequently a subset of 50 contrasting accessions were planted in the succeeding crop cycle in Bonilla. Accessions differed greatly in plant growth, root morphology and P efficiency defined as growth with suboptimal P availability. The accessions were divided into 3 categories of P efficiency using principal component and cluster analyses, and 4 categories according to the retained principal component and their relative weight for each genotype in combination with growth or yield potential. The distribution of accessions among three phosphorus efficiency classes was stable across locations. Phosphorus-efficient accessions had greater biomass, root to shoot ratio, nodal rooting, nodal root laterals, and nodal root hair density and length of nodal root main axis, and first-order laterals under P deficiency. Biomass allocation to roots, as quantified by the allometric partitioning coefficient (K) was not altered by P availability in the efficient accessions, but inefficient accessions had a lower K under low P conditions. Accessions with enhanced nodal rooting and laterals had greater growth under low P. Dense root hairs on nodal root main axes and first-order laterals conferred a marked benefit under low P, as evidenced by increased plant biomass. Late maturity improved growth and yield under low P. These results indicate that landraces of the Central Mexican highlands exhibit variation for several root traits that may be useful for genetic improvement of P efficiency in maize.     

Effect of housing environment on laying hen meat quality: Assessing Pectoralis major pH,colour and tenderness in three strains of 80–81 week-old layers housed in conventional and furnished cages

1. Meat quality is affected by factors such as stress, genetic strain and activity and is determined in part by measures of pH, colour and tenderness. In conventional laying hen cages (CC), lack of physical space and inability to perform highly motivated behaviours leads to stress and inactivity. Furnished cages (FCs) permit expression of highly motivated behaviours, but typically house larger group sizes than CC, thereby contributing to social stress. The objective of this study was to evaluate the effects of CC and FC laying hen housing environments and strain differences on meat quality of 80–81-week-old birds.

2. Pectoralis major meat quality was assessed for two flocks of Shaver White (SH), Lohmann Lite (LL) and Lohmann Brown (LB) hens housed in either 5-hen CC or 40-hen FC. Between 80 and 81 weeks, muscle samples were collected from randomly selected hens and analysed for muscle pH, colour and shear force (SF) using established methods.

3. In both flocks, the combined treatment body weights (BWs) were higher for CC than FC hens and the combined strain BWs were higher for LB than LL and SH hens. Flock 1 LB had lower initial and ultimate pH than SH and LL, and greater pH decline than SH. Muscle redness (a*) was higher for CC SH than FC SH in both flocks. Muscle a* was higher for LL than SH and LB in Flock 1, and higher than SH in Flock 2. Housing differences in muscle SF were absent. In CC, SF was higher for SH than LL and LB in Flock 1, and higher than LB in Flock 2.

4. Lack of housing differences suggests that environmental stressors present in both housing systems similarly affected meat quality. Strain differences for muscle pH, a* and SF indicate increased stress experienced by SH and LL hens. The absence of Flock 2 strain differences is consistent with the cannibalism outbreak that occurred in this flock and most severely impacted LB hens.     

Retrospective evaluation of COX‐2 expression,histological and clinical factors as prognostic indicators in dogs with renal cell carcinomas undergoing nephrectomy

Limited veterinary literature is available regarding prognostic markers for canine renal cell carcinoma (CRCC). We retrospectively evaluated COX‐2 expression, histological and clinical features associated with prognosis of CRCC. Sixty‐four cases post‐nephrectomy were included, 54 had histopathological assessment and 30 had COX‐2 immunostaining performed. Eight dogs (13%) had metastatic disease at initial diagnosis. Twenty‐seven dogs (42%) received adjuvant therapy after nephrectomy. On univariate analysis, COX‐2 expression, mitotic index (MI), histologic type, vascular invasion, neoplastic invasiveness and metastasis at diagnosis were significantly associated with overall median survival time (MST). COX‐2 score (COX‐2 score > 3 MST 420 days versus 1176 days if COX‐2 score <3; P = 0.011) and MI (MI > 30 MST 120 days versus 540 days for MI < 30; P = 0.003) were the only variables associated with CRCC outcome on multivariate analysis. The addition of MI and COX‐2 immunostaining to standard histopathological evaluation would help predicting outcome in CRCC patients.     

Evaluation of drum cavity size and planter tip on singulation and plant emergence in maize (Zea mays L.)

Thirty million hectares of maize (Zea mays L.) in the developing world are planted and harvested by hand. Indigenous planting encumbers placing two to three seeds per hill and this results in uneven spacing and decreased yields. Oklahoma State University (OSU) built a new hand planter to deliver single seeds with each strike (singulation). This planter includes a range in cavity sizes so as to accommodate different seeds. At all sites, the OSU internal drum resulted in similar emergence as the checks were planted by hand, and a John Deere vacuum planter. Developing world maize producers can use the OSU hand planter with drum “450S” if seeds are in the 2500–4000 seeds/kg range using a conventional metal tip. This planter also removes the chemically treated seed from producer's hands, reduces health risks, and serves as a mid-season fertilizer applicator.     

Preliminary Investigations of Pain and Analgesia Assessment in Horses Administered Phenylbutazone or Placebo After Arthroscopic Surgery

Twenty-five horses undergoing arthroscopic surgery were studied to develop a schemeor assessing pain in horses while investigating the effects of phenylbutazone (PBZ) analgesia. Fifteen of the 25 horses received PBZ 4 mg/kg intravenously (IV) before surgery and 2 mg/kg (IV) every 12 hours thereafter until 60 hours; the remaining 10 (placebo group) were given a corresponding volume of saline. In both groups, venous blood samples were collected for catecholamine, β-endorphin, and Cortisol assays before premedication and up to 72 hours after surgery. Postoperative pain was evaluated by measuring predefined behavioral and physiological variables. A total postoperative pain severity index (TPPSI) was calculated using all variables. There were no differences between PBZ and placebo groups in plasma β-endorphin or catecholamine concentrations, but the TPPSI was higher in the placebo group than in the PBZ group, suggesting that perioperative treatment with PBZ has some analgesic benefit. This study shows the difficulties associated with pain assessment in horses.     

beta-1,3-Glucanase Activity in Peanut Seed (Arachis hypogaea) is Induced by Inoculation with Aspergillus flavus and Copurifies with a Conglutin-Like Protein

ABSTRACT Infection of peanut (Arachis hypogaea) seed by Aspergillus flavus and A. parasiticus is a serious problem that can result in aflatoxin contamination in the seed. Breeding resistant cultivars would be an effective approach to reduce aflatoxin accumulation. The objective of this study was to investigate the expression of the pathogenesis-related (PR) protein beta-1,3-glucanase and the isoform patterns in peanut seed inoculated with A. flavus. Peanut genotypes GT-YY9 and GT-YY20 (both resistant to A. flavus infection) and Georgia Green and A100 (both susceptible to A. flavus infection) were used in this study. The activities of beta-1,3-glucanase were similar in the uninfected seed of all genotypes, but increased significantly in the resistant genotypes after inoculation in comparison with the susceptible genotypes. An in-gel (native polyacrylamide gel electrophoresis [PAGE]) enzymatic activity assay of beta-1,3-glucanase revealed that there were more protein bands corresponding to beta-1,3-glucanase isoforms in the infected seed of resistant genotypes than in the infected seed of susceptible genotypes. Both acidic and basic beta-1,3-glucanase isoforms were detected in the isoelectric focusing gels. Thin-layer chromatography analysis of the hydrolytic products from the reaction mixtures of the substrate with the total protein extract or individual band of native PAGE revealed the presence of enzymatic hydrolytic oligomer products. The individual bands corresponding to the bands of beta-1,3-glucanase isoforms Glu 1 to 5 were separated on the sodium dodecyl sulfate-PAGE, resulting in two bands of 10 and 13 kDa, respectively. The sequences of fragments of the 13-kDa major protein band showed a high degree of homology to conglutin, a storage protein in peanut seed. Conglutin is reported as a peanut allergen, Ara h2. Our data provide the first evidences for peanut having beta-1,3-glucanase activities and the association with the resistance to A. flavus colonization in peanut seed. We have not directly demonstrated that conglutin has beta-1,3-glucanase activity.     

Effect of liquid feeding weaned pigs on growth performance to harvest

Four experiments were undertaken to examine the effect of feeding postweaning diets as dry pelleted feed, fresh liquid feed, acidified liquid feed, and fermented liquid feed on pig performance from weaning (26 d) to harvest. In Exp. 1 (n = 12 replicates) and 2 (n = 10 replicates), the treatments were 1) dry pelleted feed and 2) fresh liquid feed. In Exp. 1, 2 kg of starter diet (16.7 MJ of DE/kg and 1.6% lysine) per pig and 5 kg of transition diet (16.7 MJ of DE/kg and 1.5% lysine) per pig followed by a weaner diet (14.0 MJ of DE/kg and 1.36% lysine) were offered to 27 d after weaning. In Exp. 3 (n = 8 replicates), the treatments were 1) dry pelleted feed, 2) fresh liquid feed, and 3) acidified liquid feed. In Exp. 4 (n = 8 replicates), the treatments were 1) dry pelleted feed, 2) acidified liquid feed, and 3) fermented liquid feed. In Exp. 2, 3, and 4, 3 kg of starter diet (16.1 MJ of DE/kg and 1.74% lysine) per pig and 6 kg of transition diet (15.3 MJ of DE/kg and 1.5% lysine) per pig followed by a weaner diet (14.0 MJ of DE/kg and 1.36% lysine) was offered to 27 d after weaning. All treatments were balanced for boars and gilts and diets were offered for ad libitum consumption. Acidified liquid feed was produced by adding lactic acid to the liquid feed so that its pH was decreased to 4.0. Fermented liquid feed was produced by adding an inoculum of Lactococcus lactis subsp. cremoris 303 (1.3%, vol/wt) to the first mix. In Exp. 1, ADG from weaning to d 27 after weaning was 338 and 286 g/d (SEM = 10; P < 0.01) and DM gain/feed in the same period was 888 and 594 g/kg (SEM = 23.1; P < 0.001) for dry pelleted feed and fresh liquid feed, respectively. In Exp. 2, ADG was 391 and 352 g/d (SEM = 6.4; P < 0.01) and DM gain/feed was 856 and 642 g/kg (SEM = 9.9; P < 0.001) for dry pelleted feed and fresh liquid feed, respectively, during the period from weaning to d 27 after weaning. In Exp. 3, ADG was 408, 416, and 433 g/d (SEM = 12.7; P > 0.05) and DM gain/feed was 865, 755, and 789 g/ kg (SEM = 14.5; P < 0.001) for dry pelleted feed, fresh liquid feed, and acidified liquid feed, respectively. In Exp. 4, ADG was 361, 389, and 347 g/d (SEM = 13.2; P = 0.11) and DM gain/feed was 888, 749, and 733 g/ kg (SEM = 15.8; P < 0.001) for dry pelleted feed, acidified liquid feed, and fermented liquid feed, respectively, during the period from weaning to d 27 after weaning. It is concluded that although feeding acidified liquid feed may have some merit in the first 27 d after weaning, this benefit is lost in the subsequent period. No benefit arose from feeding fresh liquid feed or fermented liquid feed. Growth performance from d 28 after weaning to harvest was not improved by any liquid feed treatment.     

Transitional cell carcinoma metastatic to the eye in a collared peccary (Tayassu tajacu)

A 15-year-old female collared peccary (Tayassu tajacu) was presented for ophthalmic examination following sudden onset of blindness. Bilateral retinal detachment was diagnosed, neoplasia suspected, and euthanasia performed. Widespread tumor dissemination was apparent at autopsy, and transitional cell carcinoma was diagnosed histologically. The tumor was identified as arising from the ovary. Epidemiologic features of this case are discussed.