Some fibroblast growth factors (FGFs) affect ovarian follicle cell growth and/or differentiation. Whereas many FGFs activate several FGF receptors, FGF7 and FGF10 primarily activate only one, FGFR2B. As FGF7 is produced by bovine theca cells and acts on granulosa cells, we tested the hypothesis that FGF10 may also play a role in folliculogenesis in cattle. Reverse transcription-polymerase chain reaction demonstrated the presence of FGF10 mRNA in the oocytes and theca cells of the antral follicles, as well as in the preantral follicles. FGF10 protein was detected by immunohistochemistry in the oocytes of the preantral and antral follicles, and in the granulosa and theca cells of the antral follicles. FGF10 expression in theca cells changed during follicle development; mRNA abundance decreased with increasing follicular estradiol concentration in healthy follicles, and was lowest in highly atretic follicles. Culturing of granulosa cells in serum-free medium revealed FSH regulation of FGF10 receptor expression. The addition of FGF10 to cultured granulosa cells decreased the level of estradiol but did not alter cell proliferation. These data support a role for FGF10 in signaling to granulosa cells from theca cells and/or the oocyte.

Paracrine cell signaling is believed to be important for ovarian follicle development, and a role for some members of the fibroblast growth factor (FGF) family has been suggested. In the present study, we tested the hypothesis that FGF-8 and its cognate receptors (FGFR3c and FGFR4) are expressed in bovine antral follicles. RT-PCR was used to analyze bovine Fgf8, Fgfr3c and Fgfr4 mRNA levels in oocytes, and granulosa and theca cells. Fgf8 expression was detected in oocytes and in granulosa and theca cells; this expression pattern differs from that reported in rodents. Granulosa and theca cells, but not oocytes, expressed Fgfr3c, and expression in granulosa cells increased significantly with follicle estradiol content, a major indicator of follicle health. Fgfr4 expression was restricted to theca cells in the follicle, and decreased significantly with increasing follicle size. To investigate the potential regulation of Fgfr3c expression in the bovine granulosa, cells were cultured in serum-free medium with FSH or IGF-I; gene expression was upregulated by FSH but not by IGF-I. The FSH-responsive and developmentally regulated patterns of Fgfr3c mRNA expression suggest that this receptor is a potential mediator of paracrine signaling to granulosa cells during antral follicle growth in cattle. IntroductionAntral ovarian follicle growth in monovular species is regulated by a number of factors, the most well known of which are the gonadotropins. Follicles are considered to be follicle-stimulating hormone (FSH)-dependent until dominance occurs, after which they become luteinizing hormone-dependent (reviewed by Fortune et al. 2001, Ginther et al. 2001. It has also become clear that growth factors are key stimulatory/regulatory molecules. Several lines of evidence point to a critical role for members of the transforming growth factor-b (TGF-b) superfamily, especially growth/differentiation factor 9 and bone morphogenetic protein 15 (reviewed by Gilchrist et al. 2004, Juengel et al. 2004, Shimasaki et al. 2004.The fibroblast growth factor (FGF) family is emerging as a group of factors that are potentially important for follicle growth. For example, FGF-7 is expressed in theca cells, its receptor is expressed in granulosa cells (Parrott & Skinner 1998, Berisha et al. 2004, and FGF-7 stimulated bovine granulosa cell proliferation and inhibited steroidogenesis (Parrott & Skinner 1998). Another potentially interesting member of this family is FGF-8. Widely expressed in fetal tissues, this factor is predominantly expressed in the gonads of adult rodents and ruminants (MacArthur et al. 1995a, Buratini et al. 2005. Within the ovary, Fgf8 gene expression occurs only in the oocyte in adult mice (Valve et al. 1997), which suggests a potential role in signaling of follicular cells by the oocyte.There are five known FGF receptor (FGFR) genes (Kim et al. 2001, Sleeman et al. 2001, of which FGF-8 preferentially activates FGFR4 and the 'c' splice form of FGFR3 (Ornitz et al. 1996). mRNAs encoding Fgfr4 or Fgfr3c were not consiste...

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Paracrine cell signaling is thought to be important for ovarian follicle development, and a role for some members of the fibroblast growth factor (FGF) family have been suggested. In the present study, we tested the hypothesis that FGF-8 and its cognate receptors (FGFR-3c and FGFR-4) are expressed in bovine preantral follicles. Reverse transcription-polymerase chain reaction was used to amplify bovine FGF-8, FGFR-3c, and FGFR-4 from preantral follicle samples and a variety of fetal and adult tissues. All three genes were widely expressed in fetal tissues, with a restricted expression pattern in adult tissues. FGF-8 and FGFR-3c were expressed in secondary follicles in 70% of fetuses examined, whereas FGFR-4 expression was significantly less frequent (20%). FGFR-3c expression frequency was significantly lower in primordial compared to secondary follicles, and FGF-8 expression showed a similar trend. FGFR-4 was only observed when all follicle classes of an individual were expressing both FGF-8 and FGFR-3c. We conclude that FGF-8 and its receptors are expressed in preantral follicles in a developmentally regulated manner.

ABSTRACT. This study aimed to evaluate the effect of probiotics on performance, intestinal morphology and carcass characteristics of broiler chickens housed on lower or higher environmental challenge. Three hundred male Cobb chicks were distributed into four groups in completely randomised design with treatments arranged in a 2 × 2 factorial scheme to evaluate effects of two diets (with or without probiotics) and two environmental conditions (lower or higher challenge), totaling four treatments with five replications with 15 birds per box. Probiotics were added on diets and were composed of Lactobacillus acidophilus, Bacillus subtilis, Bifidobacterium bifidum and Enterococcus faecium. The environment with lower challenge was made up of new wood shavings used as litter, low bird density (8 birds/m 2 ) and daily-cleaned bell drinkers. The environment with higher challenge was made up of re-used wood shavings used as litter (after three broods of broilers), bird density of 16 birds/m 2 with bell drinkers cleaned every two days. No significant interaction between diet and environmental challenge was found for any of the variables evaluated. Performance, slaughterhouse variables and chemical carcass composition were not affected by the use of probiotics. Chicks receiving diets without probiotics had lower intestinal crypt depth (267.1 vs. 316.6 μm, P=0.0068). Birds raised in the environment with higher challenge decreased feed intake (4,660 vs 5,020 g, P=0.0422), weight gain (2,610 vs 2,810 g, P= 0.0054), drumstick and thigh yield (21.98 vs 24.14 %, P=0.0354), and increased crypt depth (325.2 vs 258.5 μm P=0.0009). In conclusion, the probiotic does not promote satisfactory improvements, regardless of the environmental challenge.