硒对母猪氧化应激及其后代抗氧化能力的营养调控研究

硒作为的重要微量元素之一,可以通过胎盘和乳组织进行转移。仔猪可以从乳汁中获取硒源,提高硒含量,进而提高仔猪的初生重。同时,硒也能够调节母猪妊娠期间代谢速度,控制妊娠期自由基产生,进而提高胎盘输送营养功能。文章从母猪氧化应激体系角度来解析硒对母猪妊娠期氧化应激的调控机制、硒对哺乳母猪生产性能的调控作用。     

Association of RBP‐4 gene polymorphisms with follicular cysts in large white sows

Follicular cysts, which is a common infertility disease, can cause financial losses in pig breeding programmes. The pathogenesis and mechanisms of the formation of follicular cysts are not understood clearly. In our previous study, the concentration of retinol‐binding protein 4 (RBP‐4) in the follicular fluid (FF) of the ovary with follicular cysts was found to be significantly higher than that of normal ovary, thereby suggesting that RBP‐4 may be a candidate biomarker for porcine follicular cysts. To study the association of RBP‐4 and follicular cysts further, we detected the polymorphisms of the RBP‐4 gene and the presence of follicular cysts by PCR‐Restriction fragment length polymorphism (RFLP) assay. In this study, we screened the mutations of RBP‐4 gene in 79 sows with follicular cysts and 100 normal sows without cysts. Results showed that +249‐63G>C polymorphisms were significantly associated with follicular cysts, and sows with CC genotype in RBP‐4 gene had a high risk of developing follicular cysts. Hence, our findings further proved that RBP‐4 may be a novel biomarker for follicular cysts, which may be valuable for the diagnosis of follicular cysts and molecular breeding of pigs.     

晚稻机收留高茬紫云英迟播技术的应用效果研究

通过田间试验,研究了双季稻田晚稻机械收获留高茬后紫云英迟播的应用效果。结果表明,与传统紫云英播种技术相比,晚稻机械收获留高茬紫云英迟播显著缩短了紫云英的生育期,但其盛花期能保持与传统播种技术一致,对下茬早稻作物的种植没有影响;两种播种方法对盛花期鲜草产量、植株养分含量和养分积累量均没有显著影响,说明迟播播种能达到与传统播种一样的肥田目的;迟播对紫云英的种子产量及产量构成因素均没有明显影响,与传统播种技术相比可节约劳动力成本约45元/hm2,且可避免传统播种方法对晚稻植株的伤害。在现代双季稻种植条件下,晚稻机械收获留高茬紫云英迟播技术具有较大的优势和发展前景。     

Genetic parameters for litter size,piglet growth and sow's early growth and body composition in the Chinese–European line Tai Zumu

Genetics of piglet growth in association with sow's early growth and body composition were estimated in the Tai Zumu line. Piglet and sow's litter growth traits were calculated from individual weights collected at birth and at 3 weeks of age. Sow's litter traits included the number of piglets born alive (NBA), the mean piglet weight (MW) and the standard deviation of weights within the litter (SDW). Sow's early growth was measured by the age at 100 kg (A₁₀₀), and body composition included backfat thickness (BF₁₀₀). A main objective of this study was to estimate separately the direct genetic effect (d) and the maternal genetic effect (m) on piglet weight and daily weight gain during lactation. Variance components were estimated using the restricted maximum likelihood methodology based on animal models. The heritability estimates were 0.19 for NBA, 0.15 and 0.26 for SDW and MW at 3 weeks and 0.42 and 0.70 for A₁₀₀ and BF₁₀₀. The NBA was almost independent from SDW. Conversely, the A₁₀₀ and BF₁₀₀ were correlated unfavourably with SDW (r_g<−0.24, SE<0.12). A stronger selection for litter size should have little effect on litter homogeneity in weights. Selection for lean growth rate tends to favour heterogeneity in weights. The direct effect on piglet weight at birth and daily weight gain accounted for 12% (h² (d) = 0.02) and 50% (h² (d) = 0.11) of the genetic variance, respectively. The association between d and m for piglet weight was not different from zero at birth (r_g = 0.19, SE = 0.27), but a strong antagonism between d and m for daily weight gain from birth to 3 weeks was found (r_g = −0.41, SE = 0.17). Substantial direct and maternal genetic effects influenced piglet growth until weaning in opposite way.     

白花败酱繁育技术初步研究

采用种子繁殖、扦插繁殖和分株繁殖试验对白花败酱的繁殖技术进行研究。结果表明：上述三种方式的繁殖效果均表现良好，其中分株繁殖苗成活率近100％，且长势良好，见效最快；老枝和嫩枝在大棚内和露地的扦插成活率均在80％以上；种子发芽率虽较低，播种繁殖仍是一种较好的方法。白花败酱适应性强，适于人工繁育栽培。     

母猪热应激敏感指标体系的研究进展

母猪由于其皮下脂肪厚、汗腺不发达等特点,在高温环境下容易发生热应激。有研究表明：热应激会改变其生理状态和血液生化成分等,降低母猪繁殖力,造成严重的经济损失。然而,目前针对母猪热应激敏感指标的研究总体较粗略、评价体系不全面;而且,母猪的耐热性受遗传、年龄和日粮等多种因素的影响,使得准确评价母猪热应激状态比较困难,成为制约母猪适宜环境参数研究的重要因素。笔者在系统总结母猪热应激研究的基础上,从表型、生理、生化、分子等不同层次探讨了相关指标对热应激的敏感程度及其作为母猪热应激评价指标的可行性,以期为生产中母猪热应激诊断及环境参数的优化奠定基础。总结发现：母猪热应激敏感指标有表皮温度、呼吸频率、直肠温度、血液和肝脏热休克蛋白70（HSP70）等;比较敏感的指标有：血中皮质醇（COR）、天门冬氨酸转移酶（AST）、丙氨酸转移酶(ALT)、肌酸激酶（CK）和乳酸脱氢酶（LDH）。其他指标如血清蛋白、血糖、血液免疫细胞、K ⁺、Na ⁺等随母猪热应激也有所变化,可作为辅助参考指标。其中,表皮温度、呼吸频率、直肠温度和HSP70水平可作为评价母猪长期热应激的指标。此外,尽管母猪热应激造成的行为变化相对滞后,但其测定成本低、对动物无应激,仍然具有一定价值。     

玉米精播机漏播补偿系统设计

目前玉米免耕播种机的播种质量仍低于常规播种。本文讨论了微机控制的排种监测及漏播补偿装置，通过机电结合手段解决漏播问题。台架试验表明本装置能够准确发现漏播，并通过采取的措施实现及时补种，补种成功率可达90％以上。     

Genetic analysis for sow stayability at different parities in purebred Landrace and Large White pigs

Genetic parameters for sow stayability were estimated from farrowing records of 10,295 Landrace sows and 8192 Large White sows. The record for sow stayability from parity k to parity k + 1 (k = 1, …, 6) was 0 when a sow had a farrowing record at parity k but not at parity k + 1, and 1 when a sow had both records. Heritability was estimated by using single-trait linear and threshold animal models. Genetic correlations among parities were estimated by using two-trait linear–linear and single-trait random regression linear animal models. Genetic correlations with litter traits at birth were estimated by using a two-trait linear–linear animal model. Heritability estimates by linear model analysis were low (0.065–0.119 in Landrace & 0.061–0.157 in Large White); those by threshold model analysis were higher (0.136–0.200 & 0.110–0.283). Genetic correlations among parities differed between breeds and models. Genetic correlation between sow stayability and number born alive was positive in many cases, implying that selection for number born alive does not reduce sow stayability. The results seem to be affected by decisions on culling made by farmers.     

The Studies on the Grunting of Sows during Nursing and the Sucking Behaviour of Piglets

Two experiments were carried out to study the grunting of sows during nursing and the sucking be-haviour of piglets. In experimental I,six Yorkshire sows and their litters were observed and managed in farrowing crates.In experimental Ⅱ,six Harbin White sows and their litters were selected and housed in farrowing pens.The behaviours and activities of the sows during nursing and the actities of piglest during sucking were recorded with a portable video camera (PanasonicNV-VX22EN)The results showed that the characteristic patterns of grunting by the sows consist of an initial period of rhythmic grunting at a fairly constant rate and followesd by a period of more rapid grunting,and then a decline in grunting rate toward the completion of nursing.The pattern of vocalization showed by the mothers bears a reliable synchronization to the sucking behaviour of the piglets.The rate of grunting varied little during jostling for teat and nosing the udder.The beginning of slow sucking usually occurred during of just after the increase in grunt rate.The rapid sucking began 15-25seconds after the period of most rapid grunting,fol-lowingthe decrease of grunt rate.afterwards the nursing ended.There were individualities found in sows‘grunting patterns.It is found that vocalizations attracted the piglets to the sows and synchronized sucking activities of piglets,but the results indicated that the premassaging time and numbers of piglets enagaing massaging influ-enced the grunting pattern and the onset of the milk ejection.As more piglets were involved the massaging,the higher the grunting rate peak,the faster the milk ejection.     

营养调控对母猪繁殖性能的影响

探讨妊娠母猪妊娠早期日粮中补加一定量的甲基吡啶铬、叶酸、维生素E和维生素A对母猪窝产仔数、初生重、仔猪成活率的影响。试验分为后备母猪和经产母猪两个组,并设相应的对照组,通过试验得出妊娠母猪妊娠早期日粮中补加一定量的甲基吡啶铬、叶酸、维生素E和维生素A,结果显著地提高母猪窝产仔数,平均为29.5%,对初生重和仔猪成活率无显著影响。在母猪妊娠早期的日粮中补加甲基吡啶铬和叶酸等进行营养调控,可提高母猪的繁殖性能。