Relationship of fetal position within the uterus to fetal weight, placental weight, testosterone, estrogens, and thymosin beta 4 concentrations at 70 and 104 days of gestation in swine.

Fetal intrauterine position relative to the sex of adjacent fetuses has an effect on reproductive performance in rodents. An experiment was conducted to determine whether sex of adjacent fetuses in utero has an influence on fetal and placental weights and whether the hormonal mechanisms documented in rodents are similar in fetal pigs. Sows were slaughtered at 70.1 +/- 1.7 d (n = 123) and 104.5 +/- .05 d (n = 135) of gestation. The fetuses and placentas were removed from the uterus and the position and sex of each fetus was recorded to indicate whether the fetus was between two males, two females, or a male and a female. Fetal blood was sampled for later hormonal analysis. At 70 d of gestation, male fetal and placental weights were heavier than those of females (P less than .05), but no differences were detected relative to the sex of adjacent fetuses. At 104 d of gestation, a fetus surrounded on each side in utero by fetuses of the opposite sex (two males or two females) was lighter in weight than a fetus surrounded by fetuses of the same sex (P less than .01). Differences in fetal weight due to the sex of adjacent fetuses were not related to placental function because placental weights were generally not different at 104 d of gestation. By 104 d of gestation, most placentas were not separated by necrotic regions and were in close apposition with surrounding placentas. No differences in growth or development could be related to hormonal effects (testosterone, estrone, or estrone sulfate) from surrounding fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)     

Allometric growth of spleen and liver in black-white bovine fetuses (Bos primigenius f. taurus)

Growth relationships between spleen and liver weights and body weight and CR length as well as between weights of liver and spleen in fetuses (145 males, 141 females) of black-white cattle. According to their body weights, the fetuses were divided into 4 growth groups: I, to 1000 g; IIa, 1000-3490 g; IIb, 3500-7990 g; III, over 8000 g. The relationships were described using appropriate allometric growth equations (log Y = b log X + A) derived both for individual groups and for the entire fetal period. Relative weights of the organs studied and the liver-spleen coefficient (L/S) were determined as well. The results are presented in equations, tables, and graphs.     

Intrauterine position effects in male and female swine: subsequent survivability, growth rate, morphology and semen characteristics

Pigs of known intrauterine position were obtained from 31 litters by a procedure in which donor sows were slaughtered at d 112 of gestation, their uteri removed and piglets delivered manually. Uterine position was recorded for each piglet as being positioned between two female fetuses (OM), between a male and female fetus (1M), between two male fetuses (2M), between a female fetus and the tip of the uterine horn (OE) or between a male fetus and the tip of the horn (1E). Piglets were fostered as litter groups to recipient sows and reared in these groups until 120 d of age. They then were regrouped and housed as groups of three and six for males and females, respectively. Intrauterine position had no effect on birth weight or survivability of pigs of either sex, although pigs positioned in utero nearest the ovaries (OE and 1E) tended to be heavier at birth. Body weights were similar among groups in each sex at 120 and 175 d of age when given ad libitum access to feed; however, 2M males gained more weight from d 175 to 270 under restricted feeding conditions (P less than .05). Intrauterine position had no effect on anogenital distances either at birth or 120 d of age, and predicted testes weights were similar among males from different positions. Semen characteristics at 220 d of age did not appear to vary due to prenatal environment. Although volume tended to be less for 0M males (P less than .12), concentration, motility and sperm/ejaculate were similar among groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Response of animals to dietary gramine. II. Effects of feeding high-gramine yellow lupin seeds on reproductive performance of rats and on selected hematological and biochemical parameters in offspring.

Two groups of 26 male and 26 female rats at the initial age 30 +/- 2 days were fed during 31 weeks on diets containing 20 percent of yellow lupin seeds having low (LG) or high (HG) gramine content. The animals were mated twice within nutritional groups, 1 male: 1 female, and their main reproductive parameters were recorded. In both reproductive cycles body weight of females at mating, after parturition and after 21-days lactation was lower in HG than in LG group. Fertility rate and body weight of neonates were not affected by the diet while number of neonates per litter tended to be lower by 0.7 and 0.8 pups in HG than in LG group. Body weight of weaners was also substantially smaller in dams fed on HG than LG diet. Relative weight of spleen but not of liver, kidney and heart was significantly greater in HG females. Four weeks old males and females issued from the first litters born to LG and HG animals (ten males and ten females per treatment) were fed individually on respective diets during 3 weeks. Feed intake and growth rate did not differ between the treatments. In males relative weight of liver and testicles was greater, while hematocrit and red blood count were lower in HG than in LG group. In females organ weights did not differ. Activity of liver enzymes determined in males was not affected by the diet. It may be concluded that high-gramine lupin affects negatively lactational performance, probably via lower feed intake, but it does not induce apparent teratogenic effects in the progeny.     

Sexual differentiation in litter-bearing mammals: influence of sex of adjacent fetuses in utero

In rodents and swine, individual differences in a broad range of characteristics correlate with intrauterine position during fetal life. By identifying the intrauterine position of mice at cesarean delivery, we can predict reliably postnatal reproductive traits such as genital morphology, timing of puberty, length of estrous cycles, timing of reproductive senescence, sexual attractiveness, sexual behavior, aggressiveness, daily activity level, body weight and tissue enzyme activity in females; in males we can predict genital and brain morphology, sexual behavior, aggressiveness, daily activity level, body weight, and tissue enzyme activity. In mice, as in all mammals, male fetuses have greater concentrations of testosterone than do females. In addition, female mouse fetuses have greater circulating concentrations of estradiol than do male fetuses, a condition not found in all mammals. A mouse fetus positioned between males has greater concentrations of testosterone than does a fetus of the same sex positioned between females, and a fetus positioned between females has greater concentrations of estradiol than does a fetus of the same sex positioned between males. Gonadal steroids regulate differentiation of secondary sexual characteristics. Studies in which the effects of intrauterine position have been eliminated by exposing fetuses to steroid receptor blockers reveal the critical role of steroids in mediating this phenomenon. The intrauterine position phenomenon provides the only mammalian model for relating postnatal traits to concentrations of endogenous hormones to which individuals are exposed during fetal life. Results from studies using this naturally occurring experimental system in litter-bearing species have given insights concerning the consequences of individual differences in steroid concentrations during sexual differentiation that likely apply to all mammals. One specific hypothesis is that circulating estradiol may interact with testosterone in mediating some aspects of sexual differentiation in rodents and, thus, possibly in other mammals.     

Bisphenol-A (BPA) affects reproductive formation across generations in mice

To understand effects of Bisphenol-A (BPA) exposure on the reproductive organ across generations, we analyzed morphology of the uterus and ovary, and the methylation pattern of HOXA10 gene of the 2(nd) generation. Pregnant mice (F0) were treated with sc injection of BPA in sesame oil at various doses of 0-1,000 mg/kg Bwt on days 12-16 of gestation. Their offspring (F1) were bred by foster mice, and the offspring (F2) from F1 mice were prepared. That is, F1 mice experienced in utero BPA exposure during the developmental period of reproductive organs, while F2 mice did not at all. Using these F2 mice, the present study was carried out. Comparing to the control, the body weights in BPA exposure groups were significantly increased. Correlating with the increase of body weight, the relative weights of the ovary and uterus in each group were decreased. The histological analysis revealed expansion or emphraxis of the uterine lumen and partial loss of the uterine epithelium. Unmethylation of HOXA10 gene in the uterus was observed in the intron region. The present study suggested that BPA exposure to F0 mice could affect reproductive organ of F2 mice who were not exposed to BPA.     

Short- and long-term influence of perinatal dexamethasone treatment on swine growth

The objective was to evaluate the effects of perinatal dexamethasone (Dex) treatment on postnatal growth in pigs. Experiment 1: 42 piglets were assigned according to birth weight and sex to receive either Dex (1 mg/kg body weight) or sterile saline (Control; equivalent volume) i.m. within 1h of birth. Body weights were recorded weekly and at sacrifice (day 18). Birth weights (1.43 +/- 0.05 kg) did not differ between treatment groups (P > 0.19). At day 18, Dex pigs were heavier than Control pigs (5.46 +/- 0.24 and 4.45 +/- 0.26 kg, respectively). Serum IGF-1 was 17.3% higher in Dex pigs (P < 0.04) compared to Controls. For serum GH, there was a treatment x sex interaction (P < 0.04) with GH being 51% lower in Dex males compared to Control males, and no differences in females. Experiment 2: 71 pigs were assigned according to birth weight and sex to receive either Dex (2 mg/kg body weight) or sterile saline (Control; equivalent volume) i.m. within 1 h of birth. Body weights were recorded weekly until weaning (day 21) and then every 14th day until market weight. Birth weights (1.53 +/- 0.03 kg) did not differ (P > 0.35) between treatment groups or sexes. Dexamethasone increased growth from birth to market weight by 4.15%. Carcass weights were not different (P > 0.34) between Dex (89.9 +/- 1.17 kg) and Control pigs (88.6 +/- 1.36 kg). Overall, Dex enhanced growth in pigs from birth to market weight with minimal effects on carcass and meat quality.     

Effects of 3-methyl-4-nitrophenol in diesel exhaust particles on the regulation of reproductive function in immature female Japanese quail (Coturnix japonica)

In a previous study, we found that 3-methyl-4-nitrophenol (PNMC), a component of diesel exhaust particles and also a degradation product of the insecticide fenitrothion, exhibits reproductive toxicity in the adult male Japanese quail. The present study investigated the toxicity of PNMC in the female Japanese quail and its ability to influence reproduction in immature females. The quail (21-day-old) were injected intramuscularly (im) with PNMC at doses 0.1, 1 or 10 mg/kg body weight daily for 3 days. There was no significant difference in body growth between the PNMC-administered and control birds. However, the weights of the oviducts were significantly lower in the PNMC-treated birds at all doses. Furthermore, the plasma concentrations of luteinizing hormone (LH) and estradiol-17 beta were significantly decreased with 1 and 10 mg/kg of PNMC. These findings suggest that PNMC might influence the hypothalamo-pituitary-gonadal axis with decreasing in secretion of GnRH, LH and ovarian steroid hormones and subsequently disturb growth of the reproductive organs of immature female quail. This study indicates that PNMC induces reproductive toxicity at the central level and disrupts reproductive function in the immature female quail.     

Nutritional value and physiological effects of soya-free diets fed to rats during growth and reproduction

The objective of the study was to assess the effects of substitution milk and egg for soya products in breeding diets for rats, with concomitant decrease of the dietary protein level and supplementation with amino acids. Soya-containing (S) and two soya-free (NS and NSA) diets were evaluated as protein and energy sources, and their effects on reproductive performance during two cycles, and on the quality of the offspring were assessed. Organ weights were registered in females and blood parameters were determined in males. In the offspring males from S and NS groups, plasma LH, testosterone and prolactin levels were measured on the 22nd and the 60th day of life. The S diet contained more protein of smaller concentration of methionine and cystine and lower biological value than both NS and NSA diets and promoted similar post-weaning growth rate, similar body weight changes of dams during gestation and lactation and slightly lower mating efficiency. Within each reproductive cycle, the number and individual and total body weight of newborn and weanling pups did not differ but in two cycles mean number of neonates per litter and mean litter weight were significantly lower on S than on NSA diet. Plasma concentration of hormones did not differ in 22-day-old offspring males while in the older ones LH and prolactin levels were higher in animals fed on S than on NS diet. It is concluded that replacing soya protein by milk and egg protein with concomitant lowering dietary protein level and amino acid supplementation does not impair the growth rate and tends to improve reproductive performance. Feeding soya-free vs. soya-containing diets differentiates hormonal status of young males.     

Histochemical studies of muscle development in decapitated and hypophysectomized pig fetuses: blood vessel development

In Exp. 1, fetuses were decapitated in utero on d 45 of gestation and examined at 110 d of gestation; in Exp. 2, fetuses were hypophysectomized (hypox) in utero with a cauterizing needle at d 70 of gestation and examined at 110 d of gestation. Semitendinosus muscles were sampled and transverse cryostat sections were cut from the medial portion of the muscle. Quantitative analysis of lectin-stained sections showed that capillary:fiber ratios (C/F) were lower (P less than .01) for sections from decapitated and hypox fetuses than for sections from control fetuses. The superficial and deep aspects of muscle sections from control fetuses had markedly different C/F ratios (deep region, 24.1 +/- 2; superficial region, 11.2 +/- .5). Fetal decapitation and hypophysectomy abolished differences in C/F ratios between deep and superficial regions of muscle sections (hypox fetuses; deep region, 6.9 +/- 1; superficial region, 6.4 +/- .6). Capillaries in sections from control fetuses were reactive for several enzymes, whereas capillaries in sections from experimental fetuses (decapitated and hypox) were not reactive for these enzymes. The number of small arterioles was reduced in sections from experimental fetuses (decapitated and hypox) compared with sections from control fetuses. These studies demonstrate that lowering the levels of pituitary hormones in the fetus retards the development of blood vessels in muscle tissue both quantitatively and qualitatively.     

Fetal development in cattle with multiple ovulations.

Treatment of lactating and nonlactating parous cows (n = 379) with 12 mg of FSH-P to evaluate development of multiple bovine fetuses resulted in ovulation rates ranging from 1 to 27 corpora lutea (CL). Fertilization rate (i.e., ova fertilized at 6 to 8 d postmating, 80.0%) was not affected by ovulation rate. The percentage of fetuses developing normally at 51 to 53 d postmating decreased (P less than .01) as ovulation rate increased; 1 CL, 100.0%; 2 CL, 100.0%; 3 CL, 66.7%; 4 CL, 45.8%; 5 CL, 33.3%; 6 to 10 CL, 13.6%; and greater than 10 CL, 8.9%. Of the 86 cows permitted to calve, 47 produced singles, 22 twins, 9 triplets, 7 quadruplets, and 1 quintuplets. Calf birth weight and gestational length decreased (P less than .01) as the number of calves born increased from one to two to three. Smaller decreases (P less than .05) in birth weight occurred among triplets, quadruplets, and quintuplets, whereas gestational length did not differ (P greater than .1) among these groups. Systemic progesterone concentrations in the dam were proportional (P less than .01) to the number of fetuses in utero between d 126 and 266 for dams gestating one, two, or three or more fetuses; estrone sulfate was lower (P less than .01) in dams with one than in those with two or more fetuses. Placental weight (i.e., cotyledons plus intercotyledonary membranes) per fetus at 52 +/- 1 d of gestation and at term decreased as the number of fetuses increased. The chorioallantoic membranes were often fused among multiple fetuses and contained either all viable or all dead fetuses, but not both, within the same anastomosed placental unit. These results suggest that ovulation rate is the first limiting factor to increasing cow productivity for beef cattle because some bovine females had the capacity to gestate up to three fetuses per uterine horn, or a total of five fetuses, above which pregnancy was terminated.     

Gestational exposure to nonylphenol causes precocious mammary gland development in female rat offspring

This study examined whether or not exposure to 4-nonylphenol (NP) during late gestation affects reproductive and mammary development in the offspring of female rats. Time pregnant Long Evans rats were gavaged with NP (10 or 100 mg/kg), atrazine (ATR, 100 mg/kg), or corn oil on gestation days 15-19. The uterus weights of the NP (100 mg/kg/d)-exposed pups were higher than those of the controls but the weights of the other organs were unchanged. Delayed mammary gland (MG) development was detected in the ATR pups on PND 4 and persisted through to PND 66. The high dose NP pups had advanced lobular development of their MG on PND 22, while the glands from the low dose NP pups were no different morphologically from the controls. Immunohistochemical comparisons of the mammary sections from PND 41 demonstrated low levels of estrogen receptor (ER) staining in the control gland stroma and epithelium but higher levels in the tissue of the pups exposed to NP and ATR. ATR also elevated ER in the stroma surrounding the epithelial layer of the terminal end buds. The level of progesterone receptor (PR) staining was markedly lower in the epithelium of the 100 mg/kg NP glands vs. the control glands. However, PR was present at high levels in the epithelium of the 10 mg/kg NP glands and was even more prominent in the ATR-exposed ductal epithelium and fat cell nuclei. The level of prolactin staining was only elevated in glands containing lobule areas (NP-exposed) compared with the control levels. These results suggest that NP and ATR have opposite effects on the development of MG after gestational exposure. Exposure to them during the critical period of epithelial outgrowth altered the receptor levels of mammary progesterone and prolactin and might contribute to the differences in the mammary morphology at PND 41.     

Quantification of Sexual Steroid Hormones in Faeces of Iberian Wolf (Canis lupus signatus): A Non‐invasive Sex Typing Method

The determination of gender in wild animals is essential for behavioural and ecological studies, and also for conservation. The objectives of this study were (i) the determination of gender in faecal samples of Iberian wolf based on the differential concentrations of sexual steroid hormones (SSH) and (ii) to analyse the profiles of SSH in males and females (considering the gender determination carried out previously) during the non‐reproductive and reproductive periods. The quantification of androgens (testosterone, T), progestin (progesterone, P) and oestrogen (oestradiol, E) was conducted by means of enzyme immunoassay. The k‐means conglomerate analysis showed that the 59 faecal samples grouped into three different conglomerates, considering SSH levels. Groups 1 and 2 showed higher levels of T than group 3. Therefore, the faecal samples included in groups 1 and 2 (17 samples) corresponded to males and those of group 3 (42 samples) to females. The levels of T + P + E and T/P were higher in the group of males than in the group of females. The results of this study also showed that levels of T in males were higher during the reproductive period than in the non‐reproductive period. However, the concentrations of P and E turned out to be higher during the non‐reproductive season. In females, the levels of the three hormones (T, P and E) were higher during the reproductive period.     

Differentiation of adipose tissue and muscle in hypophysectomized pig fetuses

In the present study, fetuses were hypophysectomized (hypox) in utero on d 72 to 74 of gestation with an electrical cauterizing needle. One to six successfully hypox fetuses were removed on d 110 of gestation from each of five gilts. Subcutaneous adipose tissue samples and semitendinosus muscles were obtained from the hypox fetuses and an equal number of control fetuses. Body weights of control fetuses (n = 15; mean +/- SE, 1,195 +/- 33 g) were similar to weights of hypox fetuses (n = 15; 1,179 +/- 67 g). Fat cell size in the middle subcutaneous layer of adipose tissue was increased in hypox fetuses (P less than .01) compared with control fetuses. The number of obvious fat cell clusters (outer layer) in lipid stained sections was reduced (P less than .01) by 50% in hypox fetuses. Histochemical reactions for glucose-6-phosphate dehydrogenase, esterase and lipoprotein lipase (LPL) activities in middle layer cell clusters were considerably enhanced in sections from hypox fetuses compared with sections from controls. Quantitative analysis of percent light transmittance (Zeiss photometer) through LPL-stained cell clusters indicated an increase (P less than .001) in LPL staining in sections from hypox fetuses when compared with sections from control fetuses. Transverse muscle sections (cryostat) from hypox fetuses failed to show normal patterns (as seen in control muscles) of reactions for acid ATPase, malate dehydrogenase (NAD-dependent), NADH-TR and alpha-glycerol phosphate dehydrogenase (without NAD). The number of muscle fibers that were stained for these enzymes was greatly reduced in hypox fetuses compared with control fetuses. The number of lipid positive fibers was also reduced in hypox fetuses compared with control fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of coccidiosis on reproductive maturation of male Japanese quail

The effects of coccidiosis on reproductive development of male Japanese quail were examined. Male Japanese quail were exposed to high (5 x 10(5) sporulated oocysts/quail) or low (5 x 10(3) sporulated oocysts/quail) doses of Eimeria uzura at 16 or 30 days of age and sampled at 37 days. Quail given high doses of coccidia had reduced testes weight and lowered circulating concentrations of androgen compared with control males. Low doses of coccidia did not affect testes weight but did result in elevated plasma androgen levels. There were no differences in average testes weights by 51 days; however, plasma androgen was still reduced in most groups. To study the effects of coccidiosis on egg production, males exposed to high doses of coccidia at 16 (16H) or 30 (30H) days of age were mated with control females, and control males were mated with control or 16H females. The onset of laying was delayed for 5 days in the control male: 16H female group. During the first week of production, eggs from females bred to 30H males had lower fertility and hatchability than those bred to control or 16H males. By the third week of production, levels of fertility were similar. Apparently, exposure of quails to coccidiosis before sexual maturation might result in long-term effects on later reproductive capability.     

Age-prevalence of Otarine Herpesvirus-1, a tumor-associated virus, and possibility of its sexual transmission in California sea lions

Otarine Herpesvirus-1 (OtHV-1) is a gammaherpesvirus routinely detected in urogenital tumor tissues of adult sea lions dying during rehabilitation, To investigate the epidemiology of this virus and guide the development of a mathematical model of its role in the multifactorial etiology of cancer in California sea lions, polymerase chain reaction (PCR) amplification of an OtHV-1 specific fragment of the DNA polymerase gene was used to look for evidence of OtHV-1 infection in urogenital and pharyngeal swabs and peripheral blood mononuclear cells (PBMC) of sea lions of different ages. Samples were also examined from pregnant females and their late term in utero or aborted fetuses to investigate potential for vertical transmission. Prevalence of infection in 72 adult females was 22%, whereas it was 46% in 52 adult males, and was significantly lower in 120 juvenile animals (6%). OtHV-1 DNA was most often detected in the lower reproductive tract of the adult animals, especially the males, and rarely in the pharynx or urogenital tract of juvenile animals. These data suggest sexual transmission may an important route of transmission. Additional studies are required to confirm this mode of transmission. Additionally, the virus was detected in a single prematurely born pup, suggesting the possibility of perinatal transmission. No indication of a PBMC associated viremia was evident in adults using standard PCR or in juveniles using standard and real time PCR.     

A description of the potential growth and body composition of two commercial broiler strains

ABSTRACT

1. The potential growth of feathers and feather-free body and their chemical components was measured in two commercial broiler strains.

2. A total of 200 chicks of each sex x strain were fed adequate amounts of dietary protein using a four-phase feeding programme. Ten birds per genotype were sampled at 14, 28, 42, 56, 70, 84, 98 and 112 d of age. They were weighed before and after being dry-plucked to determine the weight of feathers, and the feather-free body was then minced and analysed for water, protein and lipid.

3. Body weights and chemical composition of males of the two strains were similar throughout the trial. Females of the two strains differed only in their body lipid contents, with mature Cobb females being higher than Ross (1371 vs. 1210 g).

4. Mature body weights of males and females from both strains averaged 8420 g and 6650 g; mature body protein weights averaged 1555 g and 1030 g; and mature body lipid contents averaged 908 and 1290 g, respectively.

5. Rates of maturing per day of body weights of males and females of both strains averaged 0.0385 and 0.0368; feather-free body protein was 0.0316 and 0.0348 and body lipid was 0.0503 and 0.0375, respectively. The rates for body lipid differed between Cobb and Ross females (0.0352 vs. 0.0397/d). Separate equations were required for males and females to describe the allometric relationship between lipid and protein in the feather-free body.

6. The rate of maturing of feathers in females was higher than in males (0.0526 vs. 0398/d) and the mature weight was lower (205 vs. 266 g), respectively. Mature body weights of broilers in this trial were considerably higher than those measured using the same protocol 24 years ago, whereas rates of maturing remained the same.     

朝鲜鹌鹑屠宰性能及其与体重的相关性分析

选择7日龄的朝鲜鹌鹑300只(公、母各半),在相同管理条件下饲养至38日龄,每周定期称重,并在38日龄时随机抽取150只(公、母各半)进行屠宰,系统分析公、母鹑的体重及主要屠宰性能指标。结果表明,除10日龄体重外,朝鲜母鹌鹑的体重均极显著地高于公鹌鹑(P<0.01);母鹑的宰前重、放血重、屠体重、半净膛重、全净膛重、半净膛率、胸肌率、腿肌重和胸肌重显著高于公鹑(P<0.05或P<0.01);相关分析显示,公、母鹑不同日龄体重间均呈极显著的正相关(P<0.01);除母鹑的半净膛率、全净膛率、胸肌重、腿肌重及公鹑的屠宰率、半净膛率、胸肌重、腿肌重外,不同日龄体重与其他屠宰性状间多呈显著的正相关(P<0.05或P<0.01)。     

Effects of supplemental vitamin E in diet of Japanese quail on male reproduction, fertility and hatchability

1. Two experiments were conducted to examine the effect of feeding higher supplemental vitamin E (VE) concentrations on male reproductive variables, fertility and hatchability of quails. 2. In experiment 1, sixty 5-week-old male quails, reared in individual cages, were fed male breeder diets supplemented with 0, 75, 150, 225 or 300 IU alpha-tocopherol acetate/kg. At 10 weeks, observations on cloacal gland size, foam production, testes weight and blood samples for testosterone estimation were taken. 3. In experiment 2, 50 male and 50 female cage-reared quails (5 weeks old) were fed male breeder and layer rations, respectively, supplemented with 0, 75, 150, 225 or 300 IU/kg. At 13 weeks, 9 different mating pairs (5 pairs/group) were formed. Group 1 contained one control male and one control female in each of 5 pens. In groups 2 to 5, control males were paired with females on supplements of 75, 150, 225 or 300 IU/kg. In groups 6 to 9, control females were paired with males on supplements of 75, 150, 225 and 300 IU/kg. During subsequent adaptation and egg collection periods, each of 10 d, control layer ration was fed to all groups. All the eggs laid during the 10-d egg collection period were incubated artificially to estimate fertility and hatchability. The trial was repeated at 15 weeks. 4. Adult male quails receiving moderate supplemental VE (75 and 150 IU/kg) had a higher cloacal gland index, quantity of foam secretion, testicular weight and plasma testosterone than quails fed on either VE-deficient or more highly supplemented diets (225 and 300 IU alpha-tocopherol acetate/kg). 5. It was concluded that a supplement of 75 IU VE/kg in maize/soybean diet could provide the best reproductive performance of male breeder quails. Cloacal gland index, quantity of foam secretion, testicular weight and plasma testosterone can serve as indirect indicators of testicular activity and fertilising ability in quails. Supplemental VE did not affect the fertility and hatchability of male and female Japanese quails.     

Fertility control of Rattus nitidus using quinestrol: effects on reproductive organs and social behavior

Fertility control has been identified by studies in the laboratory and the field as a more appropriate and long‐term control strategy for rodent pests than lethal control. In this study, we investigated the effects of quinestrol on mass of reproductive organs and on social behaviors in female and male Himalayan field rats (Rattus nitidus). A total of 16 adult females and 16 adult males were randomly assigned to 4 groups. One male and one female group were fed rice with 0.005% quinestrol by weight for 7 days, and another 2 groups were fed rice only. After 7 days, rats were assigned to 10 min dyadic encounters between groups, and investigation, aggression, defense and attack latency were quantified. All animals were killed on day 10, and reproductive organs were dissected and weighed. Dyadic encounter data showed that there were obvious changes in social behaviors of quinestrol‐treated rats. Quinestrol significantly inhibited the investigative behavior of quinestrol‐treated males toward control females in Rattus nitidus, but seldom affected investigation between control males and quinestrol‐treated females. Aggression of control females toward quinestrol‐treated males was higher than that of quinestrol‐treated females, and defense of quinestrol‐treated males toward control females was more remarkable than that of control males. Quinestrol remarkably decreased wet masses of epididymis and spermotophore in males and ovaries in females, but had no effect on wet masses of testes and uteri after quinestrol treatment. These results indicate that the anti‐fertility effects of quinestrol on R. nitidus are attributed to not only suppressing reproductive organs but also impacting social behaviors associated with territory defense and mate choice.