布鲁菌赤藓醇代谢研究概况

布鲁菌感染动物后可以逃避宿主免疫系统清除而长期存在,并严重侵害动物生殖系统。赤藓醇是布鲁菌的一种优势碳源,对布鲁菌的生长具有明显促进作用。在布鲁菌基因组中已经鉴定出6个与赤藓醇代谢相关的基因,布鲁菌的赤藓醇代谢途径也基本研究清楚。缺失布鲁菌赤藓醇代谢相关基因会造成布鲁菌在多种感染模型中的生存能力不同程度的改变。论文从布鲁菌对赤藓醇的亲嗜性、赤藓醇代谢通路及转运、赤藓醇代谢的基因调控、赤藓醇对布鲁菌毒力影响等方面进行了综述。     

Effects of a high milk intake during the pre‐weaning period on nutrient metabolism and growth rate in Japanese Black cattle

This study aimed to determine the effects of feeding an increased volume of high‐fat milk during the early post‐natal life on metabolite concentrations in the blood, the expression of key genes regulating intermediary metabolism in the skeletal muscles, and the rate of growth of Japanese Black cattle. All calves were fed a high‐fat milk replacer (crude protein, 26%; crude fat, 25.5%; total dissolved nitrogen, 116%). Control calves (n = 4) were nursed with 500 g milk replacer until 3 months of age, whereas calves in the experimental group (n = 4) were nursed with 1800 g milk replacer until 3 months, and then the volume was gradually reduced until 5 months. Body weight was significantly higher in the experimental group than in the control group at 7 months. Plasma glucose concentrations were significantly lower in the experimental group. Expression of glucose‐transporter‐4 messenger RNA (mRNA) was lower, whereas that of glucose transporter 1, cluster of differentiation 36, and carnitine palmitoyltransferase‐1b mRNA was significantly higher in the Longissimus thoracis of the experimental group. Nutritional status during early post‐natal life appears to strongly influence the growth rate and glucose and lipid metabolism in Japanese Black cattle.     

Effects of butafosfan with or without cyanocobalamin on the metabolism of early lactating cows with subclinical ketosis

Fifty‐one dairy cows with subclinical ketosis were used to investigate the effects of butafosfan alone or in combination with cyanocobalamin on metabolism. Treatments included i.v. injection of 10 ml/100 kg of body weight with butafosfan (BUT) or combined cyanocobalamin with butafosfan (BUTCO) at a similar concentration as in Catosal^®. Control cows (CON) received a 0.9% saline solution. Cows were injected on days 1–3 at 22.3 ± 0.7 days post‐partum. Milk production and composition were not affected by the treatments. In plasma, CON cows had a significantly higher plasma NEFA concentration (0.59 ± 0.03 mm ) across the study period than BUTCO cows (p < 0.05; 0.42 ± 0.03 mm ), whereas the plasma NEFA concentration of BUT was intermediate (0.52 ± 0.03 mm ) but not significantly different from CON. Both BUTCO and BUT cows had lower (p < 0.05) plasma BHBA concentrations (1.02 ± 0.06 mm and 1.21 ± 0.06 mm , respectively) across the study period than CON (1.34 ± 0.06 mm ). Plasma glucose was not different between treatments, but plasma glucagon concentrations were consistently high in BUT compared to BUTCO and CON. Lowest post‐treatment glucagon levels were observed in BUTCO. Hepatic mRNA abundance of liver X receptor α, a nuclear receptor protein involved in lipid metabolism, was higher in BUTCO compared to BUT and CON (p < 0.05) on day 7. Furthermore, on day 7, the mRNA abundance of beta‐hydroxybutyrate dehydrogenase 2 was higher in BUTCO compared to BUT and CON (p < 0.01). In conclusion, injections of combined cyanocobalamin with butafosfan post‐partum in early lactation ketotic dairy cows act on lipid metabolism with effects on plasma metabolites, most likely mediated via modified activity of key factors in the liver. Results indicate that the application of butafosfan only in combination with cyanocobalamin exhibits the expected positive effects on metabolism.     

Evidence that oxidative stress is higher in replacement gilts than in multiparous sows

The recent success obtained in term of increasing the litter size of sows has not correlated with a reduction of replacement rate. There is thus an increased economic demand for gilts with optimal reproductive potential and longevity. Unfortunately, replacement gilts are known to be more susceptible to diseases and less productive than multiparous sows. Interestingly, reproductive performance, resistance to diseases and longevity could all be largely affected by oxidative stress. To investigate whether oxidative stress conditions could account for the poor longevity of gilts, three distinct groups of conventional Yorkshire × Landrace sows were formed based on their similar age and parity (gilts, second parity sows as well as fourth to fifth parity sows). All animals were slaughtered during the post‐ovulatory period, and blood as well as tissue samples were collected. Biomarkers of oxidative damage to proteins (carbonyls) and DNA (8‐OHdG) were analysed in samples. Specific mRNA expression of major antioxidants such as glutathione peroxidases 1, 3 and 4 (GPx1, GPx3, GPx4) as well as superoxide dismutases 1 and 2 (Sod1, Sod2) were monitored in liver and kidney samples by quantitative RT‐PCR. Specific enzymatic activities of both GPx and SOD were measured by spectrophotometric assays. The plasma concentration of protein carbonyls was significantly different between the three groups with the highest concentration being observed in gilts (p ≤ 0.001). The mRNA expression levels of GPx1 and GPx4 were also significantly increased in the liver of gilts when compared to multiparous sows (p ≤ 0.05). SOD2 enzymatic activity was found to be higher in the liver of gilts than multiparous sows (p ≤ 0.05). Taken together, these results indicate that replacement gilts sustain significantly higher oxidative conditions than multiparous sows. Current findings may contribute to the design of nutritional regimens that will increase the productivity of gilts by counteracting oxidative stress.     

Transient hyperammonemia due to urea cycle enzyme deficiency in Irish wolfhounds

BACKGROUND: Irish Wolfhounds frequently have a congenital portosystemic shunt, but a considerable proportion of the 6- to 8-wk-old pups has hyperammonemia in the absence of portosystemic shunting. This hyperammonemia causes no signs and is transient, normalizing at the age of 3-4 months. HYPOTHESIS: Transient hyperammonemia has a metabolic basis in Irish Wolfhounds. ANIMALS: Two related (same sire) litters of Irish Wolfhounds (17 pups) and their parents were studied. METHODS: Integrity of the portal circulation was examined by ultrasonography and scintigraphy. Absence of parenchymal liver disease was verified by liver biopsy. Amino acid profiles were measured in 4 pups and repeated in 2 of these pups when ammonia concentrations had normalized. The amino acid profiles were compared with those of healthy Irish Wolfhound pups. RESULTS: Fasting venous ammonia concentrations were high (113-622 microg/dL, 65-345 micromol/L) in all pups, whereas bile acids were within reference range in all but 1. The ammonia and bile acid concentrations from all parents were within reference range. Portosystemic shunting was excluded in all but 1 pup. Liver biopsy excluded significant lesions in all 10 pups examined. Hypercitrullinemia was found and persisted even when ammonia had normalized, at the expense of an increase in glutamine and asparagine. CONCLUSIONS AND CLINICAL IMPORTANCE: Citrulline concentrations are controlled by the urea cycle enzymes argininosuccinase and argininosuccinate synthetase, and a defect in either of these enzymes may be responsible for the transient hyperammonemia in Irish Wolfhounds. Resolution of the hyperammonemia is associated with increased activity of alternative metabolic pathways forming glutamine and asparagine. Confirmation requires measurement of enzyme activities in liver tissue.     

Gross anatomy,computed tomography,magnetic resonance imaging and bone mineral densitometry of the ovine metacarpo/metatarsophalangeal joint

This study was aimed to provide anatomical atlas of the ovine metacarpo/metatarsophalangeal joints using computed tomography (CT) scan and magnetic resonance imaging (MRI), as well as to investigate bone mineral density (BMD) and morphometric features of this joint. The limbs of twenty adult Sanjabi sheep were examined. Imaging was performed using a 16-slice multi-detector CT scanner and a 1.5 Tesla MRI scanner. The obtained images were correlated with corresponding anatomical sections. BMD was measured by Dual Energy X-ray Absorptiometry (DEXA) method. Also morphometric features included distance between metacarpal and metatarsal heads, width of metacarpal and metatarsal head, length, width and the height of the proximal sesamoid bones were measured. In MRI images, compact bones, ligaments and tendons showed less signal intensity (hypointense). The fatty tissue and bone marrow had more signal intensity (hyperintense), but articular cartilage and synovial fluid showed moderate signal intensity. BMD in the left hind limb was significantly higher than other three limbs (p ≤ 0.05). The length of proximal sesamoid bones in left forelimb was higher than right forelimb (p ≤ 0.05). The thickness of proximal sesamoid bones in left limbs was higher than those in their counterparts (p ≤ 0.05). The width of the medial head in the forelimbs was significantly greater than the hind limbs (p ≤ 0.05). The present results might be useful in managing the clinical techniques on this joint. Larger volume of the proximal sesamoid bones and wider medial head in the forelimbs compared to the hindlimbs impel this speculation that the centre of gravity is closer to the forelimbs.     

氮素营养水平对小麦后移栽棉氮代谢的影响

对不同氮素营养水平下的小麦后移栽棉叶片硝酸还原酶活性、棉株含氮量及叶片氨基酸含量等进行了测定。结果表明，除８月１９日外，叶片硝酸还原酶活性与施氮量呈极显著正相关（ｒ＝０．９６９３～０．９８８１）；地上部各器官的含氮率和绝对含氮量均随施氮量的增加而提高，且不同器官间呈同步增减的趋势，因而氮素分配比例的变化不大；提高氮素营养水平可显著增加小麦后移栽棉的叶片氨基酸总量和游离氨的含量（ｒ＝０．５３１６和０．５６０５），在１７种氨基酸中，谷氨酸、脯氨酸等７种氨基酸的含量与施氮量呈显著的正相关（ｒ＝０．５２５６～０．６０７４）。虽然施氮量越高，棉株的氮素代谢越旺盛，但小麦后移栽棉的适宜施氮量约为２０５ｋｇ／ｈｍ２。