草原生态保护与畜牧经济可持续发展探析

在我国的综合国力不断增强,社会经济稳定发展背景下,人们的生活质量、生活水平有了明显的提升,努力做好草原生态环境的保护工作,促进畜牧业可持续发展目标的顺利实现至关重要,相关人员从新的角度、不同层面分析草原生态保护现状,进行有效对策的总结、实践经验的积累,更好地完成草原建设,畜牧经济效益的充分发挥令人十分期待。本文具体地分析了草原生态问题,并对草原生态保护、畜牧经济的可持续发展阐述了几点不同看法。     

Spermatocrit and spermatozoa density in Atlantic cod (Gadus morhua): correlation and variation during the spawning season

The utility of spermatocrit (the proportion of solid packed material in semen after centrifugation) as an indicator of spermatozoa density and male spawning stage was tested in Atlantic cod (Gadus morhua). Semen was collected from captive male cod over three spawning seasons. Spermatocrit was positively and significantly correlated with spermatozoa density measured with a Coulter counter (Multisizer), but not with spermatozoa counts in a haemacytometer. Spermatocrit increased significantly as the spawning season progressed. However, day of season explained only 35% of the variation because spermatocrit varied among individual males. Spermatozoa size remained unchanged throughout the sampling period and was not correlated with spermatocrit, indicating that variation in spermatocrit was due to variation in spermatozoa number and not their size. Spermatocrit is a good estimator of sperm density but is not reliable as indicator of spawning stage because of the variation among individual males.     

猪氟烷基因对繁殖性能的影响初探

本文采用PCR—RFLP技术检测了德阳市种畜场“九五”期间长白猪选育群第三世代123个个体的氟烷基因型,并统计分析了其中80头母猪(NN型52头,Nn型28头)头胎繁殖性状受氟烷敏感基因(Haln)影响的情况。研究结果表明,该猪群中Haln基因的频率为13.82%;NN型个体35日龄断奶成活率显著高于Nn型个体,在其他繁殖性状上二者间无显著差异,研究结果为全面了解Haln基因的遗传效应及其合理利用提供了理论依据和参考。     

Ionic composition and osmolality of paddlefish (Polyodon spathula, Acipenseriformes) seminal fluid

Changes in ionic composition as Na⁺,K⁺, Ca²⁺ and Mg²⁺, osmolality inseminal fluid, percentage of motile spermatozoaand velocity were investigated in response toCPP and different dosage of LHRHa. The lowestvelocity of sperm was observed after use CPPtreatment. The velocity of spermatozoa,significant main effect of the treatment(P < 0.0001) and the time of sperm collection(P < 0.0104) were evaluated. The osmolality ofseminal fluid was different betweenexperimental groups of LHRHa (48.0–62.7mOsmol.kg^–1) and CPP (33.0–46.3mOsmol.kg^–1) treatments. The osmolalitywas significantly higher on the first day andone-half, then declined on day three, rangingfrom 33.0 to 62.7 mOsmol.kg^–1. Analysisof variance showed significant main effects ofthe treatment (P < 0.0001) and the time ofsperm collection (P < 0.0002) on the osmolalityof seminal fluid. The level of Na⁺ andK⁺ ion was different between experimentalgroups of LHRHa and CPP treatment. The highestconcentration of 11.11 mmol.l^–1 wasobserved at Na⁺ ion. Then theconcentrations declined on the level 1.56, 0.52and 0.36 mmol.l^–1 for K⁺, Ca²⁺and Mg²⁺ ions, respectively. There werehighly positive correlations between osmolalityof seminal fluid and dosage of LHRHa treatment(r = 0.84), velocity of spermatozoa andosmolality of seminal fluid (r = 0.57) andosmolality of seminal fluid and Na⁺concentration at seminal fluid (r = 0.70).Injection with LHRHa increased quality of spermas velocity of sperm, level of Na⁺,K⁺ and osmolality at seminal fluidcompared to CPP treatments.     

Effects of photoperiod on sex steroids and gonad maturation in Arctic charr

Four groups of Arctic charr (age 3+), previously exposed to natural photoperiod, were subjected to different photoperiod regimes from February 20: Simulated natural photoperiod (SNP; Tromsø 70°N), continuous light (LD 24:0) followed by short day (LD 6:18) from either May 1 (L_Feb–May) or June 25 (L_Feb–June), or continuous light (LD 24:0) throughout the experiment (L_Continuous). In females, peak levels of estradiol-17β and testosterone were 6 and 10, 6 and 7, and 3 and 5 weeks advanced, in L_Feb–May, L_Feb–June and L_Continuous, respectively, whereas in males plasma levels of 11-ketotestosterone peaked 8 weeks earlier in L_Feb–May and L_Feb–June than in SNP and L_Continuous. Median ovulation time in L_Feb–May and L_Feb–June was advanced by 10 weeks compared to SNP and L_Continuous, and median spermiation time (first observation of running milt in each individual) in L_Feb–May, L_Feb–June and L_Continuous was advanced by 10, 7 and 5 weeks, compared to SNP. A switch from long to short day early in the reproductive cycle (L_Feb–May and L_Feb–June) apparently resulted in stronger synchronization of both ovulation and spermiation. Ovulation in L_Feb–May and L_Feb–June occurred over 3 weeks (L_Feb–May) and 8 weeks (L_Feb–June), as compared to 10 weeks in the SNP group, whereas all males (except one individual) began spermiating over a period of 3 weeks (L_Feb–June), or less (L_Feb–May), as compared to 7 weeks in the SNP group. Lack of a short day stimulus (L_Continuous), on the other hand, resulted in larger variation in the timing of final maturation, with ovulation and spermiation being spread over 15 weeks. Low egg survival in L_Feb–May (17% versus 60% and 97% for L_Continuous and SNP) indicate that a long day signal of 10 weeks early in the reproductive cycle may be too short to ensure good egg and sperm quality. Photoperiod manipulation did not affect the proportion of maturing fish.     

家畜胚胎干细胞的分离培养和鉴定

家畜胚胎干细胞的分离培养和鉴定工作对于研究和利用家畜胚胎干细胞具有重大意义。本文对文献中报道的各种分离、培养和鉴定方法进行了综述 ,并介绍了几种主要家畜的胚胎干细胞在近十余年间的研究进展情况。     

A review of spawning induction,larviculture, and juvenile rearing of the fat snook, <Emphasis Type="Italic">Centropomus parallelus</Emphasis>

The fat snook, Centropomus parallelus, is a commercially valuable marine fish species with potential for aquaculture. This paper describes the development of technology for mass production of fat snook juveniles at the Experimental Fish Hatchery of the Universidade Federal de Santa Catarina, focusing on research about reproduction, larviculture, and juvenile rearing. Induced spawning of wild fat snook was first achieved in 1991 with a single injection of human chorionic gonadotropin (hCG). There was a substantial increase in egg quality when broodstock was conditioned in maturation rooms and induced to spawn. Different dosages of luteinizing hormone-releasing hormone analogue (LHRHa) with saline injection and colesterol implant were also tested. As fat snook exhibits group-synchronous oocyte development, females could be induced to spawn (with 35–50 μg kg⁻¹ of LHRHa) once a month, resulting in up to four consecutive spawnings. Results of larval culture were highly variable at the beginning; survival rates were frequently around 1% until the juvenile stage. Several experiments were conducted to evaluate the effect of environmental factors and feeding quality on survival and growth. With the improvement of the spawning induction technique and better larviculture practices, survival rates increased to 10–30%. Studies on the particular requirements of juveniles in terms of stocking density, feeding, nutrition, and environmental factors were also performed in order to improve growth rates and feed utilization. The present study demonstrates the feasibility of mass production of fat snook juveniles. However, further research is needed to develop cost-effective grow-out technology.     

动物源性食品中尼卡巴嗪残留量的测定

动物产品中的尼卡巴嗪药物残留已被我国及美国、日本、欧盟等国家和地区列为重点检测内容,其最大残留量为0．01mg／kg-0．2mg／kg不等。为探讨合适的检测方法,本文对国内外相关尼卡巴嗪的分析检测方法的优缺点做了分析和比较,并重点介绍了动物源性食品中尼卡巴嗪残留量检测的高效液相色谱法（HPLC）和高效液相色谱-质谱联用（HPLC-MS）法。运用这两种方法进行检测,其最低检测限可达到10μg／kg甚至0．5μg／kg,基本上符合现有相关标准的限量要求。     

牛鼻绳牵出10600年前苑和囿

苑和囿是业界认定属早期园林类型之一,囿的出现不早于殷商。野牛须先驯为畜,方可进囿。牛鼻绳是嫩竹篾扭成的绳,穿进牛鼻两孔间壁肉的穿孔,大犍牛就可被驾驭。这是迄今发现最早的大家畜驯化工具,是人类从原始社会跨进农牧社会门槛的"门栓"。这是人类1万年前首次改造和利用自然、发现自我价值的时代,也是苑和囿同时涌现的时代。     

三河牛母牛产奶量及生长性状遗传参数的估测

本试验采用1984、1987、1992、1997、1998年内蒙古谢尔塔拉种牛场881头三河牛母牛的测定记录．配合动物模型BLUP方法用MTDFREML软件估计了三河牛产奶量、体尺、体重、外貌评分等7个性状的遗传力、遗传方差。得出三河牛305天产奶量、外貌评分、体高、体斜长、胸围、管围、体重的遗传力分别为0．80、O．04、0．84、0．93、0．77、0．24、0．64,并且得到了7个性状的平均值以及它们之间的遗传相关、表型相关及环境相关估计值。这些遗传参数的估计可为种畜的选择提供依据。