Dynamics of anterior pituitary immunoreactive gonadotrophs in moulted hens supplemented with protein,symbiotic and probiotics

The present work delineates redistribution patterns of the hormone‐producing cells of the anterior pituitary, after the phase of moulting. Two hundred single comb White Leghorn hens at the end of their first production cycle (Age = 70 week) were purchased from the commercial poultry farm and were induced to moult by high‐dietary zinc (3 g/kg feed/day) after 1 week of acclimatization, at the experimental research station, Department of Physiology and Pharmacology, University of Agriculture, Faisalabad. The moulted birds were equally (n = 50) and randomly allocated to their respective groups as G1 (control; CP (Crude protein) 16%, no supplement), G2 (CP18%, no other supplement), G3 (CP16%, symbiotic at does rate of 85 mg/l in drinking water daily) and G4 (CP16%, probiotic at dose rate of 85 mg/l in drinking water daily). Ten birds were slaughtered in each group at 5% and at peak of post‐moult production stage to collect their pituitary glands. An earlier post‐moult production recovery, sustained and lengthier production span was seen in the G2 as compared to all other groups. The lowest production and an earlier production decline were seen in G1. The cell diameter and area of follicle‐stimulating hormone (FSH) and luteinizing hormone (LH) gonadotroph increased (p ≤ 0.01) in G2 and G3 as compared to G1. The FSH gonadotroph nucleus diameter and area did increase (p ≤ 0.01) in G2 and G3, while LH gonadotroph nucleus diameter and area decreased (p ≤ 0.01) in G2 and G3 as compared to G1. The increased FSH and LH gonadotroph diameter in protein and symbiotic supplemented birds is accountable for the increased egg production in these groups.     

Changes in eggshell mechanical properties, crystallographic texture and in matrix proteins induced by moult in hens

The effect of moult on eggshell mechanical properties, on composition and concentrations of organic matrix components and on eggshell microstructure was investigated. The observed changes were studied to understand the role of organic matrix and eggshell microstructure in eggshell strength. Moult was induced by zinc oxide (20 g zinc/kg diet) in 53 ISA Brown laying hens at 78 weeks of age. No difference was observed for egg or eggshell weights after moult. In contrast, moult improved the shell breaking strength (28.09 vs 33.71 N). After moult, there was a decrease in the average size of calcite crystals composing the eggshell and in their heterogeneity, whereas crystal orientation remained basically the same. After moulting, the total protein concentration in eggshell increased slightly. The comparisons of SDS-PAGE profiles of the organic matrix constituents extracted before and after moulting showed changes in staining intensity of certain bands. After moult, bands associated with main proteins specific to eggshell formation (OC-116 and OC-17) showed higher staining intensity, while the intensity of the egg white proteins (ovotransferrin, ovalbumin and lysozyme) decreased. ELISA confirmed the decrease in ovotransferrin after moult. Its concentration was inversely correlated with breaking strength before moult. These observations suggest that changes in eggshell crystal size could be due to changes in organic matrix composition. These changes may provide a mechanism for the improvement in shell solidity after moulting.     

Immunocytochemical and morphometric studies on the pars distalis of the golden hamster from perinatal to senile stage

Six cell types of the pars distalis were studied from perinatal to senile stage in the golden hamster in combination with morphometric analysis and immunocytochemistry. GH cells occupied only a small area at 15 days of gestation and increased remarkably after birth to occupy a significantly larger area in the young adult than that in the other stages. PRL cells first appeared at 3 days after birth and increased rapidly thereafter to be distributed throughout the pars distalis. They always occupied a larger area in females than in males from 3 weeks after birth onward. ACTH cells were distributed mainly in the peripheral region of the pars distalis. They were dominant at 15 days of gestation, but relatively decreased after birth. The gonadotrophic cells were divided into LH cells and FSH cells. About 70% of LH cells were also immunoreactive to anti-FSH serum. LH cells occupied a larger area than that of FSH cells in every stage examined. TSH cells occupied the second largest area at 15 days of gestation, but rapidly decreased at 3 weeks after birth to occupy the smallest area among the immunoreactive cell types throughout the life-span. The chronological changes in the percentages of all cell types constituting the pars distalis seemed to reflect the activity of these cell types at a given stage.     

Induced moulting in cockerels: Effects on sperm production,plasma concentrations of luteinising hormone,testosterone and thyroxine,and on pituitary sensitivity to luteinising hormone‐releasing hormone

1. The ability of a moult‐inducing procedure to restore high levels of sperm production was assessed, in two experiments, using cockerels with reduced sperm production. The moulting procedure consisted of a period of food and light restriction for 6 weeks. The moulted birds were compared with control birds for 20 weeks.

2. Moult induction resulted in decreased daily sperm output (DSO) and plasma testosterone concentration, from weeks 3 to 7. In the first experiment, plasma luteinising hormone (LH) concentration in moulted birds was reduced on week 5.

3. No change in pituitary sensitivity to chicken luteinising hormone‐releasing hormone‐I (cLHRH‐I) was detected at week 3 in moulted cockerels. In moulted birds, a transient increase in plasma thyroxine concentration was detected.

4. After the end of moult induction, testosterone concentrations increased, plasma LH showed a rebound at week 7 and the pituitary sensitivity to LHRH was increased at week 9.

5. This increased activity of the pituitary‐testicular axis resulted for a short time in an increase in DSO of moulted birds compared with that of controls. Although amelioration was moderate, this result indicates the possibility of improving sperm production in the cockerel by using an induced moulting procedure.     

妊娠期山羊腺垂体中催乳素促卵泡素和促黄体素的分布特点

为了阐明妊娠期垂体中催乳素(PRL)、促卵泡素(FSH),促黄体素(LH)的分布和三者之间协调关系.本试验采用免疫组化SP法检测了PRL、FSH,LH三种激素在妊娠各期山羊的腺垂体细胞中免疫反应产物的分布特点.结果显示,在山羊妊娠过程中,腺垂体中PRL阳性细胞多存在于远侧部,数量逐渐增多,胞质呈强阳性;FSH和LH阳性细胞分布在远侧部和结节部,FSH胞质内颗粒着色深浅不一,LH多核膜着色;相对表达量都逐渐升高,而升高程度不同,表现为妊娠后期LH表达量急剧升高,FSH则变化较小,除了FSH的相对表达量在妊娠前期和中期之间无显著差异(P>0.05)外,3种激素的相对表达量在妊娠前期、中期和后期3个时期之间都存在显著差异(P<0.05),妊娠前、中期FSH的相对表达量均高于PRL和LH,妊娠后期LH的表达量最高.FSH次之,PRL最低.提示PRL,FSH和LH三种激素相互协同以促进胚胎着床并维持妊娠,而且在妊娠早期PRL起主要作用,之后协同FSH和LH维持妊娠.     

Comparison of moulting methods for layers: high-zinc diet versus fasting

1. The serum biochemical profiles, thyroid hormones, body weights and the production and quality of eggs subsequent to moulting, were compared in laying hens subjected to conventional forced moulting or forced moulting with a diet high in zinc.

2. A total of 200 Dekalb White laying hens in their second production cycle were studied. Blood sampling was conducted in a factorial experimental design (2 × 3) with two methods of moulting (fasting or zinc) and three sampling periods (pre-moult, moult and subsequent peak).

3. Total egg protein content, including globulins, was greater with the zinc diet, whereas egg weight and albumen percentage were greater after fasting. The zinc method resulted in an increased shell thickness and calcium percentage but lower percentage of phosphorus. During the moulting period, the hens in the zinc group had heavier mean body weights.

4. It was concluded that moulting with a high-zinc diet could replace fasting, without negative effects on body weight, biochemical variables or subsequent egg quality and production. The zinc method was also better for the birds’ welfare.

     

Cytological, Immunocytochemical and Ultrastructural Study of GH Cells of Pars Distalis Adenohipophysaria of Kids (Capra hircus)

Staining and histochemical methods, immunocytochemical and electron microscopy were used to individualize the somatotropic or GH cells in the adenohypophyseal pars distalis of the kid. They are found in a sagittal section throughout the pars distalis constituting 34% of the hypophyseal cell population. They are 12.37 micron in size and have as an ultrastructural characteristic secretory spherical granules of a large size (males, 391 nm and females, 427 nm) which are very electrodense.     

An appraisal of moulting on post-moult egg production and egg weight distribution in white layer hens; meta-analysis

1. The aim of this study was to establish how different moulting methods and body weight losses influenced post-moult performance and USDA egg weight distribution.

2. Data on 5 laying flocks (#34–38) of the North Carolina Layer Performance and Management Test were used in this meta-analysis.

3. The moulting methods were non-fasted moulted (NF), short feed restricted (SF), 13-d feed restricted (FR), non-anorexic moult programme (NA), non-anorexic moult programme with low sodium (NALS) as well as non-moulting programme as control treatment. The percentages of targeted body weight loss during the moulting period were 20, 24, 25 and 30% of body weight at the end of the first egg production cycle.

4. Post-moult egg production and egg mass were influenced by all moulting methods. Maximum increase in post-moult egg production rate and egg mass occurred with FR and NF programmes, respectively, at 30% of body weight loss, compared to non-moulted hens. Non-fasting methods reduced mortality rate more effectively than fasting methods.

5. Moulting resulted in increases in percentage of grade A and decreases in percentage of grade B eggs. Non-fasting methods increased percentage of grade A eggs more effectively than fasting methods. Percentage of cracked eggs decreased in moulted rather than non-moulted hens and the lowest rate was associated with the NA programme.

6. Post-moult egg weight was not significantly influenced by moulting methods. However, percentage of body weight reduction affected egg weight. The optimum increment in egg weight was achieved by 24% body weight reduction.

7. Overall, non-fasting methods resulted in similar egg production compared with fasting methods. Considering post-moult mortality and USDA egg weight distribution, non-fasting methods, especially NF and NA programmes, performed much better than fasting methods, indicating that non-fasting moulting methods, which are better for animal welfare, are effective alternatives to fasting methods.     

强制换羽对蛋鸡生产性能和蛋品质的影响

旨在研究强制换羽对蛋鸡生产性能和蛋品质的影响。选取80周龄海兰褐蛋鸡4 500只,分为A、B、C组,每组1 500只,于试验组Ⅰ区饲养;选取60周龄海兰褐蛋鸡3 000只,分为D、E组,每组1 500只,于试验组Ⅱ区饲养;另选取60周龄海兰褐蛋鸡1 500只（F组）,于对照组Ⅲ区饲养。试验组Ⅰ区和试验组Ⅱ区位于同一栋鸡舍,对照组Ⅲ区位于另外一栋鸡舍。采取饲料、饮水、光照控制的方式对A~E组鸡群进行强制换羽处理;F组不进行强制换羽处理。试验包括7 d的预试期和56 d的正试期。在正试期内,测定各组鸡群的产蛋率、蛋品质指标、死亡率。结果表明：与换羽前相比,强制换羽后A、B、C组的平均产蛋率的提高幅度为27.1%,强制换羽后D、E组的平均产蛋率的提高幅度为16.1%,换羽后F组的平均产蛋率的降低幅度为5.5%;5个接受强制换羽处理的试验组（A~E组）与对照组（F组）相比,蛋重增加2.5%,蛋壳强度提高11.8%,蛋白高度提高8.8%,蛋形指数提高3.3%,蛋壳尖端的厚度提高14.8%;5个接受强制换羽处理的试验组（A~E组）的平均死亡率为2.5%,对照组（F组）的死亡率为1.5%。综上所述,强制换羽技术的应用可以明显提高海兰褐蛋鸡的产蛋率,并提升蛋品质。     

Ultrastructural Classification of Three Different Rat Gonadotrophs after LH-RH Stimulation

The granule containing cells of the anterior pituitary lobe of metestrous female rats were observed by electronmicroscopy before and after i. v. injection of synthetic LH-RH. Increased granule release was found in three different types of gonadotrophs after LH-RH injection. All other known granule containing cells of the gland showed no response to LH-RH. The three gonadotrophs were morphologically distinguished on the basis of differing cytoplasmic staining and on differences in Golgi aggregation and granule diameters. Furthermore, time-dependent response-differences were observed, whereby gonadotroph type I and II responded immediately to LH-RH stimulation, type III on the other hand with a time-lag of at least 30 minutes. These time-related observations indicate that cells of type I and II secret LH, while cells of type III secret FSH.     

Variations in plasma prolactin, thyroid hormones, gonadal steroids and growth hormone in turkeys during the induction of egg laying and moult by different photoperiods.

1. Concentrations of prolactin, growth hormone, testosterone, progesterone, thyroxine and triiodothyronine were measured in the blood plasma of female turkeys during successive periods of egg laying, a decline in lay, a moult induced by a short photoperiod (6 light: 18 dark) and a resumption of egg laying induced by a long photoperiod (16L:8D). 2. Concentrations of prolactin, growth hormone, testosterone and progesterone were higher in laying birds than in birds which were moulting or not laying. 3. The concentration of testosterone, but not of the other hormones studied, increased significantly during the period of profuse moult. 4. Concentrations of the thyroid hormones did not change with the varying physiological condition of the birds. However, the concentration of thyroxine was depressed by the long photoperiod.     

Localization of the N-methyl-D-aspartate R1 Receptor in the Pituitary Gland of Immature Rainbow Trout (Oncorhynchus mykiss)

A study was conducted on the selective immunostaining of pituitary cells and pars nervosa of immature rainbow trout by antibody raised against the R1 subunit of the rat ionotropic N-methyl-D-aspartate (NMDA) receptor. In the pars distalis, the mammotrophs of the rostral pars distalis exhibited the most marked imunoreactivity, with the somatotrophs of the proximal pars distalis showing a consistently lower degree of immunoreactivity. No imunoreactivity was associated with the corticotrophs, thyrotrophs or gonadotrophs. In the pars intermedia, the melanotrophs showed no evidence of immunoreactivity, whereas the putative somatomammotrophs exhibited a wide inter-animal range of immunoreactivity. Some imunostaining was also evident in the anterior and posterior part of the pars nervosa, at the interface of the pars distalis or pars intermedia with the pars nervosa.     

哺乳动物下丘脑-垂体-卵巢轴的研究进展

哺乳动物的下丘脑、垂体和卵巢分泌的激素在功能上相互作用,构成一个完整的神经内分泌生殖调节体系,即下丘脑垂体卵巢轴,它在生殖活动中起着主要的调节作用。下丘脑中分布的GnRH神经元可以分泌GnRH,GnRH调节垂体中促性腺激素细胞分泌促性腺激素FSH和LH,促性腺激素作用于卵巢受体,引起雌激素和孕酮分泌并影响生殖活动。从组织学角度上研究,下丘脑垂体卵巢轴中的结构,如GnRH神经元、促性腺激素细胞、卵泡随周期性变化而呈现出不同的形态结构和分泌特点。因此,对以上各种细胞的研究是探讨其所分泌激素的基础,而下丘脑垂体卵巢轴中的各种激素的研究则是了解和控制动物繁殖机能的关键。     

Age and strain differences in plumage renewal during natural and induced moulting in hybrid hens

1. Replacement of remiges and body-feathers was studied in several flocks of brown and white layers and broiler-breeders under near commercial conditions. 2. Spontaneous moulting of primaries was not circannual in modern laying hybrids; moulting response was more retarded in brown than in white hens. 3. Following induction of moulting by a standard procedure in brown hens, the extent of replacement of remiges increased with increasing age, but even at 81 weeks of age, moult was not completed, but ceased when half of the flock had moulted less than half of the primaries. 4. At comparable age the moulting response was considerably more extensive in broiler-breeders than in layers; moulting was not enhanced in hens that had already started to moult before the induction. 5. Compared to the remiges, the moulting response of the body-feathers was more complete and quicker. However, these results might be influenced by a lower threshold of sensitivity to feather growth-induction of the empty follicles, the cumulative number of which is considerable among the contour-feathers after several months of laying.     

Evaluation of pituitary gland anatomy and histopathologic findings in clinically normal horses and horses and ponies with pituitary pars intermedia adenoma

OBJECTIVE: To determine size and weight of the pituitary gland and associations between pituitary gland size and weight and sex and age in horses without clinical signs associated with pituitary pars intermedia adenoma (PPIA) and horses and ponies with PPIA. ANIMALS: Pituitary glands from 100 horses without clinical signs of PPIA and 19 horses and 17 ponies with PPIA. PROCEDURES: Pituitary glands were weighed, measured, and examined histologically by use of H&E stain. Masson trichrome and periodic acid-Schiff staining were used, when appropriate. Histologic lesions in the pars intermedia, pars distalis, or both were classified as no significant lesions, single or multiple cysts, focal or multifocal hyperplasia, single or multiple microadenomas, and adenoma. Relative pituitary weight (RPW) was calculated as pituitary weight (grams) divided by body weight (grams). RESULTS: There was an age-related increase in the presence of pituitary lesions in the pars distalis and pars intermedia in geldings, mares overall, and non-pregnant mares. Mean (+/-SD) RPW in horses with PPIA was not significantly different from ponies with PPIA (15+/-5.9 x 10(-6) and 16+/-72 x 10(-6), respectively). Maximum pituitary weight in a horse with PPIA was 13.9 g (RPW, 2.9 X 10(-5)). Plasma glucose concentration was positively correlated with RPW in ponies with PPIA. CONCLUSIONS AND CLINICAL RELEVANCE: Pituitary lesions may be a factor in horses with insulin resistance and laminitis before development of clinical signs of PPIA. Ovarian steroids may be involved in the pathogenesis of lesions in the pars intermedia.     

Localization of leptin and leptin receptor in the bovine adenohypophysis

The present study was carried out to detail the cellular localization of leptin (Lep) and the leptin receptor (LepR) in the bovine adenohypophysis. Lep immunoreactivity (Lep-ir) was found in about 30% of adenohypophysial cells in the gland. Immunochemistry of Lep and specific hormones using serial sections revealed that Lep-ir was present in 60.4% of somatotrophs, 15.9% of gonadotrophs, 6.5% of mammotrophs, 6.5% of thyrotrophs and 2.4% of corticotrophs. Both the common short isoform (OBRa) and the long isoform (OBRb) of LepR mRNA were expressed in the bovine adenohypophysis. LepR immunoreactivity (LepR-ir) was found in only 2.8% of the adenohypophysial cells and over 50% of LepR-ir cells were gonadotrophs, in which most of the cells were distributed in the zona tuberalis. The findings on Lep and LepR in the adenohypophysial cells indicate that Lep may regulate gonadotroph function through autocrine/paracrine pathway in the bovine adenohypophysis.     

阉割对公马促性腺激素细胞及血中促性腺激素水平的影响

利用免疫组织化学和形态计测学的方法 ,观察了 7匹公马和 6匹在 1～ 2岁期间被摘除了睾丸的阉割马的脑垂体前叶促性腺激素 (GTH )细胞的数量和面积 ,同时利用放射免疫分析方法检测了血浆中垂体促卵泡激素 (FSH)和垂体促黄体激素 (L H)的水平。结果表明 ,公马阉割后 GTH细胞的数量和在垂体前叶实质细胞中的百分率并没有发生明显改变 ,但 GTH细胞的面积却明显增加 ,血中 GTH水平也明显升高。研究结果提示 ,处在生长发育期的马睾丸可能抑制脑垂体中 GTH细胞的合成与储存 ,也抑制 GTH的释放     

FSH分泌细胞在皖西白鹅脑垂体中的分布与定位

采用免疫组化SABC法并结合DAB显色技术时皖西白鹩脑垂体结构和促卵泡素(follicular stimulating hormone,FSH)分泌细胞进行了研究和定位.结果发现,皖西白鹅的垂体前叶由远侧部和结节部构成,没有中间部.垂体FSH免疫阳性细胞分布广泛,但前叶远侧部分布较多,从而表明皖西白鹅整个垂体都有FSH分泌,主要分泌部位在垂体前叶的远侧部.     

Comparative study of embryonal development in 2 oviparous and 1 ovoviviparous species (Gallus gallus, Coturnix c. japonica and Liolaemus tenuis t.)

In a study of the development of two oviparous species (domestic chicken and Japanese quail) and one ovoviviparous species (a common lizard), the relationship to alterations in egg size and weight during incubation was examined. It was observed, as reported by others that the avian egg diminishes in size during incubation, but that the lizard egg increases in size and weight. This investigation examines these relationships and suggests that the increase in the size and weight of the lizard egg is a result of an increase of liquid content. The mechanism is discussed.