In vitro effect of pH variations on rumen fermentation, and in vivo effects of buffers in lambs before and after adaptation to high concentrate diets

An in vitro wheat fermentation study (Exp. 1) was conducted to investigate the effect of pH (pH 7, 6, 5 and 4) on rumen lactate and VFA production. In another study (Exp. 2), lambs were fed high concentrate diets containing either no additions (control), 2% sodium bentonite, 2% limestone, 2% NaHCO3 or 10% alfalfa hay. The effect of these diets was determined on ruminal and systemic measurements before and after dietary adaptation. Effect of the control, bentonite, limestone and NaHCO3 treatments on nutrient digestibilities and mineral retentions after adaptation were also determined. Lactate production in the rumen fluid incubated at pH 7 or 6 was negligible. Reducing incubation pH from 6 to 5 resulted in accumulation of both total and L(+)-lactate, but further reduction to pH 4 did not result in an additional increase in lactate production. Variations in incubation pH or time did not affect the ratio of D to L isomers. Lowering the incubation pH to below 6 reduced total VFA production and increased the acetate to propionate ratio. In Exp. 2, the feeding of buffers or alfalfa hay was effective in maintaining a more normal feed intake and ruminal pH, and reduced ruminal lactate. Blood measurements were not affected by dietary treatment. When animals were adapted to the experimental diets, the dietary buffers did not influence rumen and blood measurements. Lambs fed 2% NaHCO3 digested more (P less than .05) organic matter, crude protein, N-free extract and starch, and 2% limestone increased (P less than .05) fiber digestibility. Dietary buffers tended to increase fecal pH and reduce fecal starch Magnesium retention with 2% bentonite, Ca retention with 2% limestone and Na and Mg retention with NaHCO3 were all increased (P less than .05).     

Extracellular cyclic adenosine monophosphate‐dependent protein kinase A autoantibody and C‐reactive protein as serum biomarkers for diagnosis of cancer in dogs

Protein kinase A, a cyclic adenosine monophosphate (AMP)‐dependent enzyme, normally exists within mammalian cells; however, in cancer cells, it can leak out and be found in the serum. Extracellular cyclic AMP‐dependent protein kinase A (ECPKA) has been determined to increase in the serum of cancer‐bearing dogs. However, there have been no reports in the veterinary literature on serum ECPKA autoantibody (ECPKA‐Ab) expression in dogs with cancer. The aim of this study was to evaluate ECPKA‐Ab and C‐reactive protein (CRP) as serum biomarkers for cancer in dogs. ECPKA‐Ab and CRP levels were detected by an enzyme‐linked immunosorbent assay in serum samples from dogs with malignant tumours (n = 167), benign tumours (n = 42), or non‐tumour disease (n = 155) and from healthy control dogs (n = 123). ECPKA‐Ab and CRP levels were significantly higher in the dogs with malignant tumours than in those with benign tumours or non‐tumour diseases, as well as in the healthy controls (P < 0.001, Kruskal‐Wallis test). There was a significant positive correlation between the neoplastic index, which was developed using ECPKA‐Ab and CRP levels, and the presence of cancer in dogs (P < 0.001); the area under the receiver‐operating characteristic curve was estimated to be >0.85 (P < 0.001). In conclusion, ECPKA‐Ab is a potential serum biomarker for a broad spectrum of cancers. Combined measurement of CRP and ECPKA‐Ab levels in serum improves the sensitivity and accuracy of a diagnosis of cancer in dogs.     

Serum Levels of Cardiac Markers NT‐proANP and NT‐proBNP in Brachycephalic bitches at Different Gestational Stages

The aim of this study was to determine serum levels of natriuretic peptide precursors (NT‐proANP and NT‐proBNP) during pregnancy in brachycephalic bitches. Fifteen healthy multiparous bitches were selected for this prospective study. Serum levels of NT‐proANP and NT‐proBNP were measured during anoestrous and at 14, 35, 42, 49 and 56 days (2nd, 5th, 6th, 7th and 8th weeks) of pregnancy. Fourteen animals had normal gestations, and one bitch developed single foetus syndrome. The natriuretic peptide levels of this animal were not included in this study; however, it is important to report that its NT‐proANP levels were four times greater than those of normal patients. There was no significant difference (p = 0.072) in NT‐proBNP levels between anoestrous (0.20 ± 0.10 ng/ml) and the different pregnancy weeks (0.27 ± 0.12 ng/ml). There was a positive correlation (p < 0.0001) between NT‐proANP and gestational age, and the levels of this marker increased significantly (p < 0.0001) during the 6th (0.26 ± 0.06 ng/ml), 7th (0.28 ± 0.04 ng/ml) and 8th weeks (0.29 ± 0.05 ng/ml) when compared to anoestrous (0.18 ± 0.02 ng/ml). NT‐proANP serum levels are correlated with gestational development and may be indicative of cardiovascular adaptation in canine brachycephalic pregnancy.     

Detection of Paranannizziopsis australasiensis in tuatara (Sphenodon punctatus) using fungal culture and a generic fungal PCR

AIMS: To describe the methods used at the Animal Health Laboratory (AHL, Ministry for Primary Industries) to identify Paranannizziopsis australasiensis.

METHODS: Skin biopsy samples from two adult male tuatara were submitted to the AHL in March 2014. Approximately half of each sample was processed for fungal culture and incubated on mycobiotic agar containing cycloheximide at 30°C. Following morphological examination of the culture products, DNA was extracted from suspect colonies. PCR was used to amplify the internal transcribed spacer (ITS) region of fungal rRNA using primers ITS1 and ITS4. Positive amplicons were subjected to DNA sequencing and the results were compared to published sequences. In addition, DNA was extracted from the remaining skin samples and the same PCR was carried out to compare the results.

RESULTS: After 7 days of incubation, colonies morphologically resembling P. australasiensis were observed. DNA extracted from these isolates tested positive for P. australasiensis by PCR and DNA sequencing. Samples of DNA extracted directly from the infected skin samples tested negative for P. australasiensis using the generic fungal PCR.

CONCLUSIONS AND CLINICAL RELEVANCE: Isolation and identification of P. australasiensis was carried out using a combination of fungal culture and molecular testing available at AHL. Results were available in significantly less time than in the past, when isolates had to be sent overseas. PCR and sequencing of fungal isolates is a valuable tool for identification of species that have few, if any, unique macroscopic or microscopic features to aid identification. Further sampling from captive and wild New Zealand reptiles will provide important information on the epidemiology of P. australasiensis, and the conservation and management implications for tuatara and other native reptile species.     

Effect of fermented total mixed rations on the growth performance,carcass and meat quality characteristics of Hanwoo steers

This study was conducted to assess the effects of fermented total mixed ration (FTMR) on the growth performance, carcass and meat quality traits of Hanwoo steers. The present study evidenced that the FTMR had a strong effect on dry matter intake, body weight, daily gain, slaughter weight and carcass characteristics compared with control animals. The results showed that the dry matter intake (7.17 ± 0.13 kg), average body weight (615.20 ± 112.82 kg), and daily gain (0.56 ± 0.16 kg) were greater in animals receiving FTMR than in control animals (P < 0.05). The meat quality characteristics indicated that cooking loss and the pH values did not vary between control and FTMR treated animals; however, animals in the treated groups (FTMR) had higher meat quality grades, carcass weight (396.13 ± 18.35), fat thickness (13.25 ± 1.75), marbling score (5.63 ± 0.56), meat color (40.06 ± 1.23), crude fat (18.39 ± 1.32) and sensory characteristics (flavor 5.03 ± 0.17; tenderness 4.42 ± 0.33; juiciness 5.10 ± 0.16). Nevertheless, the shear force values decreased significantly in FTMR‐treated animals compared with control group steers. Overall, FTMR may not only improve the growth performance, biochemical metabolites, and fatty and acetic acid profiles of steers, but may also enhance the carcass and meat quality characteristics of Hanwoo steers. Regarding economics, our research findings suggest that FTMR‐based feeds may enhance Hanwoo steer meat quality at a low cost.     

Characteristics of two duck farming systems in the Mekong Delta of Viet Nam: stationary flocks and moving flocks, and their potential relevance to the spread of highly pathogenic avian influenza

Ducks are considered to play a major role in the spread of highly pathogenic avian influenza (HPAI) H5N1 in Viet Nam, but detailed information on their management is limited. We distinguished two different systems (1) stationary duck flocks that are not commonly driven to rice fields beyond village boundaries and that are confined overnight on farms and (2) moving duck flocks that are intentionally driven to rice fields beyond village boundaries, that are not returning to home farms for extended periods and that are housed overnight in temporary enclosures in rice paddies. A total of 115 stationary and 22 moving flock farmers were interviewed in 2007 in the Mekong Delta of Viet Nam. Moving duck flocks are larger than stationary flocks, which is indicative of their more commercial production. Moving flock farmers apparently are more aware of HPAI risks than stationary flock farmers, as their flocks are more likely fully vaccinated and have less contact with chickens during scavenging. On the other hand, the spread of HPAI virus between birds might be promoted by moving duck flocks as they repeatedly use transport vehicles and numerous rice paddies for scavenging and are often visited by hatchery owners in the field for purchasing duck eggs. In addition, long distances travelled by moving duck flocks might also result in widespread dissemination of HPAI virus. Further studies are necessary to describe HPAI prevalence and travel patterns of moving duck flocks and to explore the moving duck flock network in detail.     

基于叶片SPAD的棉花氮营养指数估算研究

为了探究不同施氮处理对棉花叶片SPAD值、生物量和氮营养指数(NNI)的影响,通过两年田间试验,设置5个施氮水平（即0、120、240、360、480 kg/hm²）,开展棉花叶片SPAD值、氮素吸收分配规律和生物量变化的研究。研究结果发现：棉叶SPAD值随施氮量增加呈增加趋势,在N4处理下获得最大值;建立棉花氮浓度稀释模型：N_c=3.02W_max^-0.24,分析表明棉叶SPAD与NNI之间呈正相关关系,相关系数R²为0.05~0.74;经验证,棉花不同生育时期的模型模拟性能较好,出苗后97天时相关系数达到最大。棉花叶片SPAD值与临界氮浓度存在显著的正相关关系,可以作为棉花氮营养诊断的指标。     

漂白紫胶贮存性质的研究(第三报)——紫胶树脂卤化及脱卤反应产物结构的研究

为了证实紫胶漂白过程中生成的不稳定结合氯和稳定结合氯在树脂分子上的位置,用壳脑酸和壳脑酸二甲酯与溴反应模拟了紫胶树脂与游离氯之间的反应。两者的溴加成产物分别为α,β-二溴壳脑酸和α,β-二溴壳脑酸二甲酯,后者的脱溴产物为β-溴壳脑酸二甲酯.用各种波谱确定了上述3个化合物的结构.实验展示了在漂白过程中游离氯加成在紫胶树脂的萜烯酸双键上生成α,β二氯衍生物,脱氯时α位结合氯和β碳原子上的一个氢原子作为氯化氢脱落而恢复双键,留下β位上稳定的结合氯.     

大兴安岭西伯利亚红松及其形态学的研究

经一系列考察研究证实,我国50年代后期于大兴安岭发现的所谓“漠河红松”,应属西伯利亚红松Pinus sibirica,而并非红松P.koraiensis。天然红松实际上不入大兴安岭。西伯利亚红松主要覆被西、中西伯利亚地区。在我国大兴安岭,仅偶见于西北隅,属首次发现。种的鉴定,除根据一般常用形态性状鉴别外,还以解剖镜、光学显微镜与扫描电镜相结合,对针叶表皮上的下陷气孔外口及其在角质层上的印痕,进行了一系列的比较研究。结果发现,西伯利亚红松的气孔外口,乃至表皮细胞,也与红松明显不同,应视为一可靠鉴别特征。