The reproductive tactics and activity patterns of solitary carnivores: the Iriomote cat

Felids are generally considered to be crepuscular and nocturnal in their activity, but few studies have attempted to analyze the variability of their activity patterns. We studied the daily activity of the Iriomote cat Prionailurus iriomotensis by radio-tracking on Iriomote Island, Japan. The general activity patterns of Iriomote cats showed slightly prevailing activity during dark periods of the day with particular peaks at dawn and dusk or during the early hours of the night. However, these patterns were clearly dependent on the sex and reproductive status of the cat. Peaks of cats’ activity coincided with those of their main prey. On average, the cats were active for thirteen hours per day. During the mating season, the rhythm of activity in males followed that of breeding females, but not that of non-breeding ones. Males exhibited 11% higher total daily activity and longer active bouts during the mating period than in the remainder of the year. Breeding females had additional mid-day activity peak during the nursing period, but their total time of activity per day was 16% lower than in the period of kittens’ independence. Their active bouts were shorter and more frequent during nursing than at other times. These results suggest that lactating females perform frequent movements to and from the den site to care for kittens. During the non-nursing period, females increased their activity, possibly in response to lowered prey abundance and the need of intensive foraging to recover after lactation. Seasonal and sexual variation of activity patterns in the Iriomote cats confirmed the existence of different reproductive strategies of males and females of these solitary carnivores.     

Reproductive biology of the endemic Iranian cichlid, <Emphasis Type="Italic">Iranocichla hormuzensis</Emphasis> Coad, 1982 from Mehran River,southern Iran

We studied the reproductive biology of the endemic Iranian cichlid Iranocichla hormuzensis, a maternal mouthbrooder, in the Mehran River. Overall sex ratio was 1.44 M: 1F indicating a significant male bias. Monthly sex ratios did not differ from unity except in May and June when the sex ratios were strongly biased in favor of males. Four different reproductive indices and the high frequency of large oocytes, all suggest that the Iranian cichlid spawns at the end of winter and the beginning of spring. Mircoscopic gonadal maturation stages for both males and females were correlated to the gonadosomatic indices. The maximum number of larvae in the mouth of a female was 153.     

Fungus gardens of the leafcutter ant Atta colombica function as egg nurseries for the snake Leptodeira annulata

Attine ants are well known for their mutualistic symbiosis with fungus gardens, but many other symbionts and commensals have been described. Here, we report the discovery of two clusters of large snake eggs in neighboring fungus gardens of a mature Atta colombica colony. The eggs were completely embedded within the fungus garden and were ignored by the host ants, even when we placed them into another, freshly excavated fungus garden of the same colony. All five eggs contained embryos and two snakes eventually hatched, which we identified as being banded cat eyed snakes Leptodeira annulata L. Ant fungus gardens are likely to provide ideal climatic conditions for developing snake eggs and almost complete protection from egg predation. Our observations therefore indicate that mature banded cat eyed snakes are able to enter and oviposit in large and well defended Atta colonies without being attacked by ant soldiers and that also newly hatched snakes manage to avoid ant attacks when they leaving their host colony. We speculate that L. annulata might use Atta and Acromyrmex leafcutter ant colonies as egg nurseries by some form of chemical insignificance, but more work is needed to understand the details of this interaction. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

What affects fertility of sexed bull semen more, low sperm dosage or the sorting process?

Until now it has been unclear to what extent the reduced fertility with sexed semen in the dairy industry is caused by too few sperm per AI dose, or by the effect of flow cytometric sorting, which is the established procedure for sexing semen. Therefore, we evaluated the effects of low sperm numbers per dose with and without sorting on non-return rates after 56 days (NRR56); in addition, we evaluated the effects of bulls, in order to further optimize use of sexed semen.Based on results of using sexed semen from seven Holstein bulls, an overall numerical decline of 13.6% in NRR56 was observed (P < 0.05). About two-thirds of this decline (8.6%) was due to the low dose (P < 0.05), and a third (5.0%) due to the process of sorting (P < 0.05). The effect of low dosage and sorting differed among bulls. We observed a sex ratio of 91.6% females for sexed semen from the first 131 calves born.Currently the best way to increase fertility of sexed semen is by closely monitoring fertility so that the highest fertility bulls are used, and by improving farm animal management. However, to make substantial progress, more in depth studies are needed on the sexing technology, especially on aspects such as sorting procedures and sperm dosage.     

多囊卵巢综合征猕猴的生殖特性(英文)

多囊卵巢综合征(PCOS)是临床上常见的一种内分泌失调性疾病,也是造成无排卵性不孕的重要原因。对多囊卵巢综合征动物模型的研究有10余年,迄今尚未建立起较为理想的模型动物。该研究的目的在于构建猕猴多囊卵巢综合征动物模型,并分析该模型动物的一些主要生殖特性。将6只成年雌性猕猴(6～10a)平均分成2组:PCOS模型组和对照组。模型组动物的建立方法是:在月经周期的第1、3、5天,分别皮下注射丙酸睾丸酮一次,剂量为3.5mg/kg体重;接着在第7、9、11天,分别肌注人绒毛膜促性腺激素一次,剂量是350IU/kg体重;连续注射2个月经周期。对照组动物注射生理盐水。结果显示:PCOS模型组动物呈现出高血清LH和T,分别为(5.35±0.17)IU/L和(7.58±0.14)ng/mL,而且血清LH/FSH值(5.35/1.30=4.12);模型组动物血清FSH、E2和P的含量与对照组无显著差异。腹部B超扫描结果提示,模型组动物卵巢多囊化。对两组动物进行超排处理后,模型组动物卵巢呈明显的过刺激现象,模型组动物胚胎体外培养的囊胚率为23.53%,显著低于对照组(66.67%)(P<0.05),即用丙酸睾丸酮联合人绒毛膜促性腺激素,能够建立PCOS猕猴模型,该模型动物的一些主要生殖特性与人类PCOS相似。     

Circulating small non-coding RNAs provide new insights into vitamin K nutrition and reproductive physiology in teleost fish

Background

Vitamin K (VK) is a fat-soluble vitamin known for its essential role in blood coagulation, but also on other biological processes (e.g. reproduction, brain and bone development) have been recently suggested. Nevertheless, the molecular mechanisms behind its particular function on reproduction are not yet fully understood.

The effect of administering equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG) post artificial insemination on fertility of lactating dairy cows

The objective was to evaluate the effect of equine chorionic gonadotropin (eCG) and hCG post artificial insemination (AI) on fertility of lactating dairy cows. In Experiment 1, cows were either treated with eCG on Day 22 post AI (400 IU; n = 80) or left untreated (n = 84). On Day 29, pregnant cows were either treated with hCG (2500 IU; n = 32) or left untreated (n = 36). Pregnancy and progesterone were evaluated on Days 29 and 45. In Experiment 2, cows (n = 28) were either treated with eCG on Day 22 (n = 13) or left untreated (n = 15) and either treated with hCG on Day 29 (n = 14) or left untreated (n = 14). Blood sampling and ultrasonography were conducted between Days 22 and 45. In Experiment 3, cows were either treated with eCG on Day 22 post AI (n = 229) or left untreated (n = 241). Pregnancy was evaluated on Days 36 and 85. In Experiment 1, eCG on Day 22 increased (P < 0.02) the number of pregnant cows on Day 29 (50.0 vs. 33.3%) and on Day 45, the increase was higher (P < 0.01) in cows with timed AI (41.2 vs. 6.5%) than in cows AI at detected estrus (50.0 vs. 37.8%). Pregnancy losses were reduced by eCG and hCG, but increased in cows that did not receive eCG but were given hCG (P < 0.01). Treatment with hCG tended (P < 0.06) to increase progesterone in control cows, but not in cows treated with eCG. In Experiment 2, hCG increased (P < 0.01) the number of accessory CLs on Day 35 (28.5 vs. 0.0%) and tended (P < 0.07) to increase progesterone. In Experiment 3, eCG increased the number of pregnant cows (P < 0.05) on Days 36 and 85, but only in cows with low body condition (eCG = 45.6 and 43.5%; Control = 22.9 and 22.9%). In conclusion, eCG at 22 days post insemination increased fertility, primarily in cows with low body condition and reduced pregnancy losses when given 7 days before hCG; hCG induced accessory CLs and slightly increased progesterone, but hCG given in the absence of a prior eCG treatment reduced fertility.     

Expression profiling of cumulus cells reveals functional changes during ovulation and central roles of prostaglandin EP2 receptor in cAMP signaling

To understand the role of prostaglandin (PG) receptor EP2 (Ptger2) signaling in ovulation and fertilization, we investigated time-dependent expression profiles in wild-type (WT) and Ptger2^−/− cumuli before and after ovulation by using microarrays. We prepared cumulus cells from mice just before and 3, 9 and 14 h after human chorionic gonadotropin injection. Key genes including cAMP-related and epidermal growth factor (EGF) genes, as well as extracellular matrix- (ECM-) related and chemokine genes were up-regulated in WT cumuli at 3 h and 14 h, respectively. Ptger2 deficiency differently affected the expression of many of the key genes at 3 h and 14 h. These results indicate that the gene expression profile of cumulus cells greatly differs before and after ovulation, and in each situation, PGE₂-EP2 signaling plays a critical role in cAMP-regulated gene expression in the cumulus cells under physiological conditions.     

Characteristics, abundance and fertility of orphan eggs of the Lesser Rhea ( Pterocnemia-Rhea-pennata pennata ): implications for conservation

The Lesser Rhea (Pterocnemia-Rhea-pennata pennata) has a complex reproductive system that combines polygyny with sequential polyandry, in which males build the nest, fully incubate the eggs and care for the young. As occurs with the Greater Rhea (Rhea americana), Lesser Rhea females sporadically lay eggs outside the nest (‘orphan’ eggs), which are not incubated and thus fail to hatch. We have examined the orphan eggs of Lesser Rhea over two separate breeding seasons to determine their abundance and fertility status. During 2004 and 2005, weekly ground searches for orphan eggs were conducted in a wild population of Lesser Rhea in northwestern Patagonia, Argentina. During these searches the total number of nests, eggs in each nest and orphan eggs laid outside the nests was recorded. Orphan eggs represented approximately 7% of the total eggs laid in a breeding season. Six fresh orphan eggs were artificially incubated, four of them being fertile. Orphan eggs seemed to have two origins: some were laid near deserted nests in the early to mid-reproductive season; others were probably laid by first-time breeders and were found later in the reproductive season. Given the near-threatened status of the Lesser Rhea, harvesting and artificial incubation of orphan eggs, which otherwise would be unproductive, may contribute significantly to the conservation of this species, i.e., ‘recovered’ birds could be used for reintroduction or reinforcement of wild Lesser Rhea populations.