如皋黄鸡连产性状及其遗传参数分析

本文通过对如皋黄鸡两个世代(9世代866只,10世代423只)常规选育性状(开产日龄、开产体重、开产蛋重及40周龄产蛋数)和连产性状(连产周期、平均连产长度、最长连产长度、平均间歇天数、最长间歇长度及连产强度)进行统计分析,估计各性状的遗传力及之间的遗传相关并分析表型相关。结果表明:与常规选育性状相比连产性状的变异系数较大;9世代连产周期遗传力最高为0.523,开产体重和平均连产长度为中等遗传力性状(0.417和0.310),开产日龄、开产蛋重、40周龄产蛋数、最大连产长度、平均连产间歇天数、最长间歇天数及连产强度为低遗传力性状(0.068~0.244);40周龄产蛋数与平均连产长度、连产强度呈正遗传相关和极显著表型相关,与连产周期、最长连产间歇呈负的遗传相关和极显著表型负相关。以40周龄产蛋数为主选目标间接使10世代连产周期数下降,连产长度延长,而连产周期数的遗传力下降。综上,与40周龄产蛋数相比,连产性状中的连产周期和平均连产长度的遗传力估计值较高,与其遗传相关和表型相关均较高,可将连产性状作为选育指标对如皋黄鸡进行进一步选择。     

儋州鸡不同产蛋时期生殖激素分泌规律的研究

为研究儋州鸡不同产蛋时期生殖激素的分泌规律,采用ELISA方法对儋州鸡母鸡开产前期、开产期、产蛋高峰期及产蛋后期4个时期血液中促卵泡素(FSH)、促黄体生成素(LH)、催乳素(PRL)、孕酮(P)、雌二醇(E_2)的浓度进行测定。结果显示,开产期与产蛋高峰期FSH与LH浓度极显著高于开产前期和产蛋后期(P0.01);不同产蛋时期血液中PRL浓度呈上升趋势,且开产前期和开产期PRL浓度显著低于产蛋后期(P0.05);不同产蛋时期血液中E_2浓度呈下降趋势,且产蛋后期E_2浓度显著高于开产前期和开产期(P0.05),极显著高于产蛋高峰期(P0.01);开产期与产蛋后期P的浓度较高,均显著高于开产前期(P0.05),且极显著高于产蛋高峰期(P0.01)。研究表明,儋州鸡在不同产蛋时期血液中生殖激素含量水平有不同的变化,开产期血液中FSH、LH及P浓度较开产前期明显升高;产蛋高峰期血液中FSH与LH的浓度高于其他时期;产蛋后期血液中PRL、E_2、P的浓度较产蛋高峰期明显上升,且负反馈调节FSH与LH的分泌量。     

光照对鸡产蛋性能的影响及机理研究Ⅱ.光照对母鸡血浆雌二醇、黄体生成素和甲状腺素的影响

将70日龄星杂“579”小母鸡120只,随机分成A、B、C三个组。C组为自然光照组,A、B两组分别以32和8~(lx)的强度补充光照,使其每天的光照时间达14h。用放射免疫分析法测定了三组鸡在100～180日龄期间外周血浆雌二醇(E_2)、黄体生成素(LH)和甲状腺素(T_4)的水平。结果表明,B组鸡LH增加最显著,其峰值(149日龄)与基础值(100日龄)相比,增长率为231.4％,且与开产期早、产蛋量多关系最密切;A组鸡T_4水平显著增高,但其产蛋量相对降低,从而提示降低T_4水平及代谢率对产蛋可能有利;补充光照能促使外周血浆E_2峰值的出现早于自然光照组,但峰值之间无显著性差异,表明光照能促进鸡的性成熟,而光照刺激鸡产蛋似乎与E_2无明显关系。     

番鸭就巢期生殖激素水平的变化规律

对番鸭就巢期不同时间的血浆生殖激素水平进行测试,揭示了不同就巢时间血浆生殖激素浓度变化的规律,并对就巢与激素之间的相关性进行分析。结果表明:(1)抱窝期血浆PRL含量(0.68±0.11ng/mL)极显著高于醒抱期的含量(0.33±0.04ng/mL)(P<0.01);(2)醒抱前后血浆LH含量差异很大,醒抱后LH含量(33.17±15.49mIU/mL)极显著高于抱窝期含量(5.56±1.99mIU/mL)(P<0.01);(3)抱窝期血浆E2含量(0.9±0.65ng/mL)极显著低于醒抱期含量(1.9±1.17ng/mL)(P<0.01);(4)PRL与LH、PRL与E2、LH与E2之间的相关系数分别为-0.923、-0.666和0.641。     

影响蛋鸡产蛋的因素

<正>1产蛋周期与产蛋率优良品种蛋鸡一般可以连续产4~6个蛋,然后休产1~2天,呈现周期性产蛋现象,称之为产蛋周期。产蛋率是指某一段时间内鸡实际产蛋的个数。鸡产蛋率的高低与产蛋周期内连产的个数有关。鸡一般是白天产蛋,通常是前一个蛋产出约30分钟,开始下次排卵,产蛋周期和连产特性主要受遗传因子决定。产蛋周期越长,则产蛋量越高,反之产蛋周期越短则产蛋量越低。2季节和光照春季不论高产蛋鸡或是低产蛋鸡,产蛋周期都     

西藏多玛绵羊同期发情处理及外周血液激素含量变化研究

本研究采用孕酮阴道栓（CIDR,CIDR组）和氯前列烯醇（PGF2α,PG组）2种方法，分别对40头2～3岁、体重（65.12±6.41）kg的西藏多玛绵羊进行同期发情处理，对同期发情效果进行比较，并在处理后第1、4、7、10、13、16天和第19天（08:00）、（20:00）连续收集血清进行促卵泡素（FSH）、促黄体素（LH）、雌二醇（E2）和孕酮（P）浓度测定。结果表明：CIDR组和PG组的同期发情率达到100%，但CIDR组的受胎率和分娩率高于PG组（P<0.05）,2组分娩母羊产双羔的比率没有显著差异。处理过程中激素变化结果表明：CIDR组和PG组中FSH和LH激素变化趋势基本一致，CIDR组中第7天E2水平高于PG组（P<0.05）,CIDR组第1、4和第19天的P浓度高于PG组（P<0.05）。在CIDR组中，FSH与E2、LH与P的变化显著相关（P<0.05）。总体上，CIDR组的同期发情处理的效果优于PG组，激素变化和相关性分析均显示CIDR组处理方式优于PG组。     

mC3d3-DINHα(1～32)基因免疫对大鼠卵泡发育和生殖激素的影响

选择32只60日龄雌性性成熟大鼠分为4组,分别肌肉注射pcDNA-DPPISS-DINH(试验组1) 50 μg,pcDNA-DPPISS-DINH-mC3d3 (试验组2) 50 μg,空载体pcDNA3.1 (对照组1) 50 μg,生理盐水(对照组2)1 mL.首次免疫20、40 d后各组分别同剂量同样免疫程序加强免疫注射1次.结果发现,试验1和2组卵巢的重量都显著高于对照组1和2,但试验1和2组之间的差异不显著(P＞0.05);试验2组卵巢成熟卵泡发育个数和FSH的浓度显著高于试验1组和对照1和2组(P＜0.05);加强免疫第40天,试验1、2组的E2的浓度分别显著高于本试验组免疫前第0天,免疫后第20天的激素浓度;试验组与对照组在各个免疫试验时间LH的浓度在统计上差异不显著(P＞0.05).结果证明,应用重组抑制素真核表达质粒pcDNA-DPPISS-DINH-mC3d3(试验组2)免疫动物可以促进大鼠卵泡的发育,可提高血浆FSH、E2水平,为抑制素基因免疫大动物提供了试验依据.     

不同能量水平饲粮对云上黑山羊泌乳期繁殖激素的影响

试验研究了饲粮能量对羊繁殖激素的影响。选择60只云上黑山羊哺乳母羊,分为3组,分别饲喂3个不同能量水平饲粮。每个组随机选择5只母羊,在母羊产羔后第1、7、14、21、28、42 d采血。同时在这15只母羊发情时连续间隔12 h采血3次,测定血清促卵泡素(FSH)、促黄体生成素(LH)、雌二醇(E2)、孕酮(P)和催乳素(PRL)浓度。结果表明,第21 d中水平组FSH和LH浓度最高(P0.01);第1 d高水平组E2浓度高于中水平组(P0.05);第21 d,中水平组E2浓度高于高水平组(P0.01);发情12 h内高水平组E2浓度最高(P0.05);第42 d中水平组P浓度高于低水平组(P0.05);第28 d中水平组PRL浓度最高(P0.05);发情36 h低水平组PRL浓度最高(P0.01)。研究发现,饲粮能量水平对云上黑山羊泌乳期及泌乳期发情阶段的生殖激素没有显著影响,仅得到了云上黑山羊母羊繁殖激素的基础数据。     

肉用种母鸡血浆促黄体激素浓度和初产年龄的光照反应曲线

此试验目的是为了准确定义限饲条件下肉用种母鸡的光诱导促黄体激素（LH）分泌的反应曲线,并与光照反应曲线进行比较,以改进母鸡初产年龄（AFE）。选择平均体重为2．0kg的20周龄肉鸡,分别转移经受8、9、9．5、10、10．5、11、11．5、12、12．5、13、14、18h的光照,4d后测定血浆促黄体激素变化浓度,并记录个体的初产年龄。促黄体激素分泌最先显著增加的是转移到11．5h光照组的鸡,     

FSH对多浪羊子宫和卵巢组织及血清生殖激素的影响

为了探讨外源激素卵泡刺激素(FSH)在诱导绵羊超数排卵过程中子宫和卵巢形态、卵泡数量及8种生殖激素浓度变化情况,试验选取30只健康经产多浪羊,随机均分为超数排卵(DC)组和同期发情(DT)组,同时埋植孕酮缓释硅胶栓(CIDR),记为第0天;DC组在埋栓后第11,12,13天依次递减注射FSH,DT组不做处理;在埋栓后第13天两组均撤栓并注射前列腺素(PG)。从埋栓第11天开始每组屠宰3只多浪羊,至第15天结束,摘取子宫和卵巢,观察子宫和卵巢形态,记录卵巢优势卵泡数量,采用ELISA试剂盒检测外源FSH处理后多浪羊血清中8种生殖激素FSH、促黄体生成素(LH)、雌激素(E2)、孕酮(P₄)、促性腺激素释放激素(GnRH)、PG、抑制素(INH)和瘦素(LEP)浓度的变化。结果表明：多浪羊经过埋栓处理后卵巢中优势卵泡数量随着时间推移先增加后减少,DC组的平均优势卵泡数量高于DT组。第15天DC组个别卵巢表面可观察到“红体”出现,而DT组未发现。在注射FSH后,DC组中FSH和LH激素浓度持续增加,第13,14天时显著高于第10～12天(P<0.05);E2浓度先...     

Comparisons of time intervals and plasma LH concentrations during the ovulatory cycle of broiler breeder hens maintained under either a 24 h light:dark cycle or continuous light

The possibility that egg production in broiler breeder hens may be increased by selection for reduced oviposition interval under continuous light was investigated by comparing the pattern of pre-ovulatory releases of plasma luteinising hormone (LH) and the associated ovipositions in the same broiler hens maintained under normal cycles (15.25 h light/d) or continuous light. The lighting conditions had no effect on plasma concentrations of LH before and at the pre-ovulatory LH peak in first, mid-sequence or terminal ovulatory cycles. Plasma LH concentrations were similar during first, mid-sequence and terminal ovulatory cycles. Mid-sequence oviposition intervals and the interval between a mid-sequence LH peak and its associated oviposition were longer under continuous light than under normal lighting. Pre-ovulatory releases of LH occurred during a restricted period of day in both lighting conditions. Under continuous lighting they were probably entrained by the daily pattern of restricted feeding. Any selection programme for reduced oviposition interval under continuous lighting in broiler breeder hens should take into account the entraining effects of the daily pattern of feeding.     

Ovarian follicular growth and maturity and follicular production of progesterone and oestradiol in response to porcine luteinising hormone and porcine follicle stimulating hormone in albino (S*AS) hens in vivo and in vitro

The effects of the SAS gene on follicular growth were studied by feeding Sudan IV and Sudan Black B, on follicular maturity by measuring P4 and E2 output of the 5 largest follicles (F1 to F5) in vitro, and on ovarian response (plasma progesterone, P4, and oestradiol, E2) to administration of porcine follicle-stimulating hormone (pFSH) and porcine luteinising hormone (pLH) in old laying hens. Albino hens had fewer dye rings in the yolks of their eggs than non-albinos (8.32 compared to 8.59) and the yolks from albinos weighed less. The numbers of normal and atretic follicles larger than 3 mm in diameter did not differ between the two genotypes. The P4 outputs from the F1 and F2 follicles were significantly greater for albino hens, but P4 production of other follicles was not different for the two genotypes. The P4 output of the F1 follicle in response to pLH was dose-dependent and greater for albino hens than for non-albinos. Porcine LH did not increase the follicular E2 output in either genotype. Administration of pLH, but not pFSH, increased plasma P4 and E2 concentrations, with no difference between genotypes. These data suggest that the F1 follicles for albino hens are precocious, resulting in a reduced growth period and a smaller weight at ovulation.     

增蛋散对蛋鸡内分泌及消化作用的影响

将768只421日龄海兰白蛋鸡随机均分为2组,分别饲喂添加0和1.5%中药增蛋散的2种饲料,于饲养30、60d时采血和屠宰,测定血样中卵泡刺激素(FSH)、促黄体素(LH)、三碘甲状腺原氨酸(T3)、甲状腺素(T4)、雌二醇(E2)、孕酮(P4)、甲状旁腺素(PTH)、环磷酸腺苷(cAMP)等的含量及饲料中粗蛋白和钙的消化率,探讨该散剂促产蛋的作用机制.结果显示,当日粮中添加增蛋散饲喂30、60 d时,蛋鸡血清中FSH、LH、T3、T4、E2、P4、PTH的含量,下丘脑和腺垂体中cAMP含量及饲料中粗蛋白和钙的消化率均有显著提高(P＜0.05或P＜0.01).本试验结果为该散剂提高产蛋后期鸡的产蛋率,推迟其淘汰期的药理作用提供了实验依据.     

Comparison of the basal and luteinising hormone-releasing hormone induced luteinising hormone release by perifused hypophyses from turkey hens (Meleagris gallopavo) at different physiological stages.

1. An experiment was performed to investigate the weight of the ovary, the oviduct, the pituitary gland, the plasma concentrations of luteinising hormone (LH), progesterone, oestradiol and the responsiveness of the pituitary gland in vitro to doses of Luteinising Hormone-Releasing Hormone (LH-RH) ranging from 10(-10) to 10(-5) M in laying (L), incubating (I) and out-of-lay (OL) turkey hens. 2. Pituitary weights did not differ between the groups but the weights of the ovary and oviduct and the plasma concentrations of progesterone and oestradiol were lower in I and OL than in L hens. The plasma concentrations of LH were lower in I than in L hens. 3. In vitro, the basal release of LH was similar in L and I hens, but significantly higher in OL hens. A slow and linear increase in basal LH release by the glands from I and OL hens was observed throughout the experiment. 4. No clear dose-response relationship was found in any of the reproductive states with respect to LH release in vitro following LH-RH stimulation, probably as a result of partial cell desensitisation. On the other hand, the amount of LH released over basal level in responses to stimulation with different doses of LH-RH were not significantly different between L and I hens, but they were between 5- to 10-fold higher in OL hens, except at the lowest dose. 5. These findings confirm that there is no correlation between circulating LH in turkey hens and the capacity of the hypophysis to release LH in vitro passively or in response to LH-RH. Therefore, the low circulating concentrations of LH in I and OL turkey hens cannot be accounted for by decreased adenohypophyseal responsiveness to LH-RH. They may indicate a low level of hypothalamic secretion of LH-RH and/or to the existence of an inhibitory mechanism on LH secretion in vivo in both OL and I hens.     

Hormonal patterns of boars exposed to natural or supplemental lighting during pubertal development

Thirty-two crossbred boars (Hampshire X Duroc X Yorkshire) were reared under natural lighting (35 lx) or supplemental lighting (1,400 lx) beginning at 4 wk of age. Boars received supplemental lighting from six 40-W fluorescent bulbs between 0530 and 2030 in a nursery unit. From 9 to 32 wk of age, boars received either natural lighting (30 lx) or supplemental lighting (100 lx) in a growing-finishing unit. Blood samples were collected from indwelling cannulae at 20-min intervals for 6 h every 2 wk from 2.5 to 7 mo of age. Libido scores were evaluated during alternate weeks when intensive blood samples were not taken. Libido scores were not different between natural and supplemental lighting treatments (P greater than .30). However, at 122 d of age, libido scores of boars exposed to supplemental lighting tended to be higher (P = .10) than those exposed to natural lighting. Although mean serum concentrations of luteinizing hormone (LH) were higher (P less than .05) in boars at 75, 89, 103 and 131 d of age reared under supplemental lighting than boars of the same age reared under natural lighting, the number of LH secretory spikes was similar between the treatment groups (P = .39). Serum concentrations of LH decreased in both treatment groups as boars became older (P less than .05). However, the incidence of LH spikes was similar across ages and between treatment groups from 2.5 to 7 mo of age. Mean serum concentrations of follicle stimulating hormone and testosterone were similar between treatments (P greater than .75).     

Lighting regimens and plasma LH and FSH in broiler breeders

Egg production by meat-type fowl is markedly inferior to that from commercial laying hens, and so, to assess the degree to which photorefractoriness might be a contributing factor, male- and female-line broiler breeders were maintained on 8-, 11- or 16-h photoperiods. In addition, to determine the age-related rate of change in response to an increment in photoperiod, other birds were transferred from 8- to 16-h photoperiods at 67 or 124 d. Blood samples were taken from all groups, except those on constant 11-h photoperiods, in both genotypes at 67, 69, 124 and 126 d, and from all lighting groups in the female line at 58 weeks (end of trial), and the plasma was assayed for plasma luteinising hormone (LH) and follicle stimulating hormone (FSH) concentration to investigate possible correlations with rate of sexual maturity, total egg numbers and terminal rates of lay. Prepubertal LH was consistently higher for the female line than for the male line, and higher for 16-h birds than for 8-h birds. At 69 and 126 d, LH values were not significantly different from those 2 d earlier for 8-h birds, but significantly reduced for 16-h birds. There was an increase in LH following photostimulation at 67 d, but no significant change after the 124-d light increase. There were no significant differences in FSH between the two genetic lines, nor any effect of photostimulation at 67 or 124 d. There was a tendency for FSH in 8-h birds to be higher than for 16-h birds, and this difference became significant for male-line birds at 67 d. At 58 weeks, LH was higher for constant 11- and 16-h birds and for birds photostimulated at 67 d than for constant 8-h controls or birds transferred from 8 to 16h at 124 d. Neither baseline nor photoinduced prepubertal changes in plasma LH nor FSH were found to be of value for predicting age at sexual maturity or subsequent rates of egg production. At 58 weeks, LH was not generally correlated with sexual maturity, total eggs or terminal rates of lay, however, there was a negative correlation with age at first egg in birds photostimulated at 124 d. It must be concluded that plasma LH and FSH concentrations are of minimal value to the broiler breeder industry for predicting the degree of photorefractoriness, the age at sexual maturity, or subsequent egg production.     

Concentration of steroid sex hormones in the plasma of hens in relation to oviduct tumours

1. The concentrations of 17 beta-oestradiol (E2) and progesterone (P) were determined in the plasma of layer breeder hens at the end of their first laying season, in relation to neoplasms of the oviduct, including magnum tumours and leiomyomas. 2. The plasma concentration of E2 was higher in tumorous than in non-tumorous hens indicating it may be involved in the development of oviduct tumours. 3. The plasma concentrations of P in tumorous and non-tumorous hens were not significantly different, suggesting no active role of P in the aetiology of the tumours. 4. The E2: P ratio was higher in tumorous than in non-tumorous hens. This ratio could be of value in predicting hens at risk of developing oviduct tumours.     

GnRH-1 mRNA, LH surges, steroid hormones, egg production, and intersequence pause days alter in birds exposed to longer wavelength of light in the later stages of production in Gallus gallus domesticus

The objective of this was to establish the effects of red spectrum of light (650 nm, treated n = 12) and normal spectrum of light (450 nm control = 12) on GnRH-I mRNA expression, amplitude and frequency of luteinizing hormone (LH), and egg production from 72-82 weeks of age in white leghorn hens. Birds exposed to red spectrum of wavelength significantly improved (P < 0.01) steroid hormone, and egg production improved over old laying 72 to 82 weeks. Weekly interval profiles followed the same pattern. At 77th weeks of age blood, samples from both the groups were collected at every 3 h for 36 h to study the pulsatile secretion of LH surges. Plasma LH concentration was higher (P < 0.01) in treated birds with more number of frequencies and amplitude LH surges in plasma of treated birds. LH frequencies were more pronounced and advanced during 36 h of sampling at 3 h interval in treated birds. Weekly interval of plasma LH, E2β, and P(4) concentrations increased (P < 0.01) in treated birds from 72 to 82 weeks of age. GnRH-I mRNA concentration was significantly (P < 0.01) higher in birds exposed to red spectrum of light compared to controls. It is hypothesized that exposure of birds to red spectrum of light-enhanced (P < 0.01) GnRH-I mRNA with more number of yellow yolky follicles was found in birds exposed to red spectrum of light during 77 days (72-82 weeks of age) of experimental period. It is concluded that higher levels of GnRH-I mRNA, LH, E2β, and P(4) concentration with lower incidence of pause days enabled the birds to lay more eggs even later in the productive period by modulating the wavelengths of light under normal husbandry conditions.     

Role of ovarian steroids in the control of moult induction in laying fowls

1. Thirty-five Warren SSL hens were selected on the basis of variation in moulting response following a force-moult at 81 weeks of age. Fourteen hens were from a group which returned to layers mash ad libitum from day 9, while 21 came from a group with dietary restriction prolonged to day 28. Blood samples were taken on days 23 and 36, and hormone concentrations were measured. Moulting was recorded on days 0, 11, 23, 36, 52 and 68. 2. Progesterone (P4) but not oestradiol (E2) inhibited moulting during egg laying and the sharp fall in P4 concentration when laying ceased was a primary factor in the induction of moulting. 3. Thyroxine (T4) concentrations were closely correlated with all criteria of plumage renewal, but not with the onset of moulting. Although T4 was closely correlated with subsequent feather growth it is questionable whether T4 is a primer of moult-induction independent of P4. 4. Feathers which were pulled out required 12 +/- 2 d to be replaced beyond the feather-papillae stage. For remiges this timing was similar regardless of whether hens were moulting or still laying. The timing was similar for remiges and body-feathers in moulting hens, but the reappearance of body-feathers in laying hens was slightly delayed.