Cryptorchidism is a common reproductive abnormality, possibly resulting from abnormal hormone production/action by the fetal testis. Insulin-like factor 3 (Insl3) is thought to be involved in gubernaculum development and transabdominal testicular descent, but its importance is unclear, due partly to lack of suitable Insl3 antibodies. We generated (by genetic immunization) and validated a novel antirat Insl3 antibody, which we used to characterize immunoexpression of Insl3 in rat Leydig cells (LCs) from fetal life until adulthood and its relationship to cryptorchidism. Immunoexpression was strong on embryonic day (E) 17.5 and E19.5 and from 35 d of age onward but weak from E21.5 until puberty. Because in utero exposure to di (n-butyl) phthalate (DBP) induces cryptorchidism and suppresses Insl3 gene expression, we investigated Insl3 protein expression in fetal and adult rats exposed to 500 mg/kg.d DBP from E13.5 to E21.5. Expression on E17.5 and E19.5 decreased dramatically after DBP exposure, but there was no consistent correlation between this suppression and abnormal testis position. We also compared expression of Insl3 and P450 side-chain cleavage enzyme in fetal testes from rats exposed in utero to DBP or flutamide (50 mg/kg.d). DBP treatment suppressed expression of both P450 side-chain cleavage enzyme and Insl3 at E19.5, but flutamide exposure had no effect on either protein, demonstrating that Insl3 expression in fetal rat LCs is not androgen regulated. In adult rats, Insl3 expression was suppressed in 80% of cryptorchid and 50% of scrotal testes from rats exposed to DBP, suggesting that prenatal DBP exposure also leads to maldevelopment/malfunction of the adult LC population in some animals.

The aim of the present study was to assess whether the whole meiotic process of spermatogenic cells is able to take place in vitro. Fragments of seminiferous tubules from 20-to 22-or 28-day-old rats were seeded in medium containing 0.2% fetal calf serum in bicameral chambers and then cultured for 4 weeks in a chemically defined medium. The differentiation of meiotic germinal cells was followed by four criteria: (i) ultramicroscopic examination of the different types of germ cells present in the cell layer throughout the culture period; (ii) determination of the changes in DNA content per nucleus of the cell population seeded with time in culture; (iii) assessment of the ability of germinal cells to transcribe genes expressed after completion of meiosis; and (iv) monitoring the fate of BrdU-labeled leptotene spermatocytes. The ultrastructural study showed that the overall organization of the cells in the culture well recalls that of the seminiferous epithelium throughout the culture period. Moreover the identification of young round spermatids 21 days after seeding suggested that these spermatids had been formed very recently in culture. Determination of DNA content per nucleus showed that a 1C cell population could be observed after several days of cultures reaching 6 to 10% of total cells. An exponential-like increase in the amounts of the mRNAs encoding for TP1 or TP2 occurred from the time when 1C cells appeared in the culture until the end of the experiment. Finally, BrdU-labeled leptotene spermatocytes differentiated into pachytene spermatocytes and then into secondary spermatocytes, and BdrU-labeled round spermatids were observed from Day 21 of culture onward. Taken together these results indicate that the whole meiotic process from leptotene spermatocyte to round spermatid can indeed occur in vitro under the present culture conditions.

Current vaccines to Escherichia coli mastitis have shown some albeit limited efficacy. Their mode of action has not been documented, and immune responses protecting the mammary gland against E. coli are not completely understood. To improve our knowledge of mammary gland immune protection, cows immunized either intramuscularly or intramammarily with the E. coli P4 were submitted to a homologous mastitis challenge. A third group of mock-immunized cows serve as challenge controls. Local immunization modified favorably the course of infection, by improving bacterial clearance while limiting inflammation. Systemic clinical signs and reduction in milk secretion were also contained. This occurred with a modification of the cytokine profile, such as an increase in IFN-γ and a reduction in TNF-α concentrations in milk. Concentrations of IL-17A and IL-22 increased in milk at the onset of the inflammatory response and remained high up to the elimination of bacteria, but concentrations did not differ between groups. Accelerated bacteriological cure was not linked to an increase in the initial efficiency of phagocytosis in milk. Results support the idea that antibodies did not play a major role in the improvement, and that cell-mediated immunity is the key to understanding E. coli vaccine-induced protection of the mammary gland.

Automation of phenotypic measurements of livestock has become a more important goal for scientists and also for farmers who need a more precise, real-time knowledge of their animals. Among physiological measures, body temperature and its variations are key indicators of the physiological health and well-being of animals. Although measuring the body temperature may seem a trivial matter, its implementation is faced with many difficulties both at biological and technological levels in a field of constant progress. Today, there are many studies reporting taking temperature measurements without restraining animals. The present report focuses on the two main approaches to temperature measurements that use direct contact or radiation sensors. Specifically, we investigated the use of thermocouples, thermistors and infrared radiation sensors. A wide literature review using one of these techniques was conducted in which different animal species, different purposes, different experimental designs, various equipments, and different devices and gold standard methods are discussed. These technologies will continue their dizzying development, leading to new communication protocols, sensors miniaturization and a more efficient management of energy. These developments will have a direct impact on the increase of reading distances and the amount of information stored. In response to the request of farmers and researchers, integrated monitoring systems are already marketed with user-friendly interfaces and softwares for complex data storage and treatments.

Spermatogenesis is a finely regulated process of germ cell multiplication and differentiation leading to the production of spermatozoa in the seminiferous tubules. Spermatogenesis can be divided into three parts: spermatocytogenesis, meiosis and spermiogenesis. During spermatocytogenesis, germ cells engage in a cycle of several mitotic divisions that increases the yield of spermatogenesis and to renew stem cells and produce spermatogonia and primary spermatocytes. Meiosis involves duplication and exchange of genetic material and two cell divisions that reduce the chromosome number and yield four haploid round spermatids. Spermiogenesis involves the differentiation of round spermatids into fully mature spermatozoa released into the lumin of seminiferous tubules. The seminiferous epithelium is composed of several generations of germ cells due to the fact that new generations of sperm cells engage in the spermatogenic process without waiting for the preceding generations to have completed their evolution and to have disappeared as spermatozoa into the lumen of the tubules. In bulls, the duration of the seminiferous epithelium cycle is 13.5 days. The total duration of spermatogenesis is 61 days, that is 4.5 times the duration of the cycle of the seminiferous epithelium. The spermatogenetic wave is used to describe the spatial arrangement of cell associations along the tubules. Several theories have been described to explain the renewal of spermatogonia. Depending on the model, there are five or six spermatogonial mitoses explaining the renewal of stem cells and the proliferation of spermatogonia. Daily sperm production and germ cell degeneration can be quantified from numbers of germ cells in various steps of development throughout spermatogenesis. Bulls have a lower efficiency of spermatogenesis than most species examined, but higher than that of humans.

Although this culture model is clearly unsuitable for preparing germ cells for therapeutic purposes, it does represent a most valuable tool for testing the effects of biological and chemical agents on testicular tissue.

The aim of the present study was to set up a culture system allowing most of the meiotic phase of rat spermatogenesis to occur in vitro. For that purpose, the differentiation of spermatogenic cells was monitored by three criteria: 1) examination of expression of genes specifically expressed at a high level in pachytene spermatocytes (the phosphoprotein p19 [p19] and the testis-specific histone TH2B) or in round spermatids (transition protein 1 [TP1] and transition protein 2 [TP2]) by reverse transcription-polymerase chain reaction (RT-PCR); 2) ploidy analysis; and 3) cytological and immunocytochemical study of the germ cells. In the first trial, we determined the changes in the ratios of p19:TP1 and TH2B:TP2 mRNA-related PCR products in the whole testis of rats between 18 and 60 days postpartum and related those results to the sequential appearance of the various types of spermatogenic cells during that period. In the second trial, our aim was to reproduce, in a culture system using seminiferous tubules from 23- to 25-day-old rats, the changes observed in vivo. The p19:TP1 and TH2B:TP2 ratios decreased dramatically in testicular extracts of rats between 32 and 40 days postpartum, i.e., at the time period during which round spermatids become more and more numerous in the testis. When seminiferous tubules were seeded in bicameral chambers, cell viability remained close to 70% of total cells throughout the 3-wk culture period. Both p19:TP1 and TH2B:TP2 ratios decreased during the first week of culture. This was attributable to a decrease in the levels of p19 and TH2B mRNAs and also to an enhancement in the relative amounts of TP1 and TP2. These changes were correlated with the appearance of a 1C cell population in the culture. Histological examination of the culture demonstrated that under the conditions of the present study, 5-bromo-2'-deoxyuridine-labeled pachytene spermatocytes of stages IV-VI were able to differentiate into secondary spermatocytes, then into round spermatids.

Vaspin, also known as visceral adipose tissue-derived serine protease inhibitor, is a member of the serine protease inhibitor family. Its expression is associated with obesity, insulin resistance and type 2 diabetes, and elevated concentration is observed in polycystic ovary syndrome. However, vaspin has never been studied in the ovary. Here, we identified vaspin in two prolific breeds of pigs: fat Meishan (MS) and lean Large White (LW). We then investigated the molecular mechanism involved in the regulation of its expression in response to gonadotropins, insulin, insulin-like growth factor type 1 (IGF-1) and steroids (progesterone, testosterone and oestradiol) in ovarian follicles cells. Using real-time PCR and Western blot, we found higher vaspin mRNA and protein expression in the ovarian follicles and adipose tissue at 10–12 days of the oestrous cycle in MS compared to LW. Moreover, vaspin expression, as well as its concentration in plasma and follicular fluid, decreased in ovarian follicles of LW during days of the oestrous cycle, while the opposite results were noted in MS. Immunohistochemistry showed vaspin in granulosa, theca, cumulus cells and oocytes as well as in adipocytes. Vaspin level in the ovary increased by gonadotropin, insulin, IGF-1 and steroids stimulation through kinases JAK/Stat, ERK1/2, PI3K and AMPK, as well as factor NF-κB. These findings all show vaspin expression and regulation in the pig ovary, indicating vaspin as a new regulator in female reproduction. Future studies will be necessary for understanding the role of vaspin on ovarian physiology providing new insights into the pathology of ovaries.