不同处理方法对美国截叶胡枝子种子发芽的影响

美国截叶胡枝子的硬实率很高,发芽率只有17.3%.经过种子预处理,如采用不同温度下浸种、98%浓硫酸浸泡、机械破皮和机械破皮结合热水浸种等处理,结果表明,机械破皮后用60℃热水浸种处理的效果最好,发芽势和发芽率分别达到64.0%和74.3%;其次是机械破皮,平均发芽率达到50%;浓硫酸浸种可以显著提高种子发芽势,浓硫酸浸种5min效果最好,发芽率达到44.7%;热水浸种的处理效果不佳,最好的90℃热水浸种处理发芽率也仅有26.7%.     

Application and Commercialization of Flow Cytometrically Sex-Sorted Semen

The current technology to sort X and Y chromosome bearing sperm population requires individual identification and selection of spermatozoa in a modified high-speed flow cytometer. For farm animal species, the technology is capable of producing sexed sperm at greater than 90% purity. However, only in the bovine, the technology has reached a developmental level that allows its commercial application. Meanwhile, the demand for female calves has grown rapidly, which encourages the demand for sex-sorted semen from high genetic value bulls. The success of the technology will depend mainly on the fertilizing capacity of the sorted spermatozoa, as this is the most affecting and economically relevant factor. To date, fertility is still variable and is quite dependant on post-sort processing. New processing techniques are under investigation and will likely be able to improve the fertility rates after AI with sex-sorted semen. It is of great importance to select the right bulls and to test the sorted samples on a routine basis. In addition to the demand for sex-sorted semen by the cattle industry, there is also a significant demand expressed by pig farmers. However, it is still unknown if the use of sex-sorted semen through commercial pig AI will be economically feasible. For the pig, the combination of in vitro fertilization with sexed semen and non-surgical embryo transfer is an alternative that merits further scientific attention. Recent developments in ovine AI and ET will make it very likely that commercial sheep industry will adopt the sexing technology in their breeding concepts.     

TOTAL ANOMALOUS PULMONARY VENOUS CONNECTION IN A FOAL

An 8-day-old Arabian-Morgan cross colt underwent cardiac evaluation. The foal was tachycardic, tachypneic, exercise intolerant and had a loud right-sided heart murmur and cyanotic mucous membranes. Total anomalous pulmonary venous connection was diagnosed with echocardiography and confirmed at postmortem examination. Total anomalous pulmonary venous connection is a very rare congenital cardiac abnormality that has not been reported before in the horse.     

Broiler pulmonary hypertension syndrome. I. Increased right ventricular mass in broilers experimentally infected with Aegyptianella pullorum

Infection with the obligatory intra-erythrocytic anaplasma-like rickettsia Aegyptianella pullorum in 4-week-old broilers at a moderate altitude of 1,200 m produced a significant increase in the mean relative right ventricular (RV) mass (RV: TV) from 0.23 in the controls to 0.31 in the infected group. This was accompanied by an increase in the number of birds suffering from severe RV hypertrophy from 14.3% in the controls to 50% in the infected group. Pulmonary hypertension and subsequent RV hypertrophy could have been caused by the severe anaemia experienced in the course of the infection or by metabolic or biochemical action of A. pullorum. As the agent does not occur on commercial broiler farms, it cannot play a practical role in the broiler ascites syndrome.     

不同处理方法对美国截叶胡枝子种子发芽的影响

截叶胡枝子(Lespedezacunecta)是原产于亚洲东部的一种多年生的豆科植物,在我国南方地区野生分布很广。它具有耐瘠、耐旱、耐酸、耐热、固土能力强、适应性广等特性,在国外也颇受重视。我国于1983年从美国引种,通过对其生物学和生态学特性、经济性状和栽培技术研究证明,引进的美国截叶胡枝子在人工栽培条件下,表现出良好的经济性状,是南方草地改良的希望种子。但是在生产中,由于其硬实的存在,使得种子的发芽率很低,往往造成出苗困难和草地建植缓慢,甚至出现严重缺苗断垄的现象,直接影响田间产量,限制了它的进一步推广应用。试验采用不同处…     

Is sperm cryopreservation in absence of permeable cryoprotectants suitable for subfertile donkeys?

Sperm from fertile donkeys have been successfully frozen in absence of permeable cryoprotectants. The aim of this study was to determine whether this cryopreservation method is suitable for subfertile donkeys in comparison to conventional sperm freezing with glycerol. Ejaculates were collected from four Andalusian Donkeys: three fertile and one subfertile. Semen was frozen with an extender containing glycerol (GLY), or adding instead sucrose 0.25 molar and 1% bovine serum albumin (SUC) as non‐permeable cryoprotectants. After thawing, samples were assessed for total (TM, %) and progressive (PM, %) sperm motility by CASA, plasma membrane integrity (PMI, %) by epifluorescence microscopy and DNA integrity (DFI, %) by SCSA. Results (mean ± SD) were compared between extenders in fertile and subfertile donkeys using the Student's t test. No differences between GLY and SUC treatments were found in the fertile group for the sperm parameters assessed. In subfertile donkey ejaculates, GLY resulted in significantly higher values than SUC for TM (25.5 ± 3.1 vs. 19.6 ± 1.9) and PM (13.3 ± 5.1 vs. 4.0 ± 1.2), respectively. In conclusion, considering all the sperm parameters assessed, sperm freezing in absence of permeable cryoprotectants may not be still an option for cryopreservation of subfertile donkey sperm.     

Resting metabolic rates increase with elevation in a mountain‐dwelling lizard

Individuals that inhabit broad elevational ranges may experience unique environmental challenges. Because temperature decreases with increased elevation, the ectotherms living at high elevations have to manage limited activity time and high thermoregulatory effort. The resting metabolic rate (RMR) of a postabsorptive animal is related to its total energy requirements as well as many other fitness traits. Mesquite lizards (Sceloporus grammicus) living on La Malinche Volcano, Mexico, inhabit a wide elevational range with some populations apparently thriving above the tree line. We measured the RMR of lizards from different elevations (i.e., 2,600, 3,200, and 4,100 m) at four ecologically relevant temperatures (i.e., 15, 25, 30, and 35 °C) and found that RMR of mesquite lizards increased with temperature and body mass. More importantly, lizards from the high‐elevation population had mass specific RMR that was higher at all temperatures. While the higher RMRs of high‐elevation populations imply higher metabolic costs at a given temperature these lizards were also smaller. Both of these traits may allow these high elevation populations to thrive in the face of the thermal challenges imposed by their environment.     

Regional distribution and integrity of equine ovarian pre‐antral follicles

The goal of this study was to determine the distribution of pre‐antral follicles in the ovarian parenchyma of mares. For Experiment 1, each ovary was cut longitudinally at the greater curvature, performing two hemiovaries. After that, six fragments from each hemiovary were obtained, resulting in 12 fragments, which were divided into the innermost region of the parenchyma, the middle region and the outermost region. All the three obtained sections were cut transversally to obtain two fragments from each one. For Experiment 2, each ovary also submitted to a longitudinal cut on the greater curvature, forming two hemiovaries. Each hemiovary was sectioned into four symmetrical fragments, resulting in eight fragments per ovary. The fragments were related as being near to or far from the ovulatory fossa. The fragments of both experiments were immediately fixed in Carnoy for 12 hr and kept in 70% ethanol for 24 hr. Follicles were classified according to the stages of development and for morphological integrity according to oocyte morphology and granulosa cells. After the histological assessment, a total of 1,130 follicles were visualized from Experiment 1, being 1,054 (93.3%) primordial follicles and 76 (4.7%) follicles in development. The innermost region had the highest percentage of pre‐antral follicles compared to the other regions (p < .05). The middle and outermost regions showed higher percentages of intact primordial and developing follicles than the innermost region (p < .05). Considering Experiment 2, 938 follicles were found, being 894 (95.3%) primordial and 44 (4.7%) follicles in development. The region near the ovulatory fossa presented higher (58.7%; 551 of 938) follicular concentration compared to the region far from the ovulatory fossa (41.3%; 387 of 938; p < .05). As a conclusion, distribution of pre‐antral follicles in the equine ovary has a specific pattern through the parenchyma. Also, the follicular integrity differed in the studied ovarian areas.