17-estradiol and the influence of native and oxidised chylomicron remnants on cholesterol esterification in thp-1 cells k. batt *, m. napolitano, e. bravo, m. avella*, k. botham*. *the royal veterinary college, london nw1 0tu, uk; sect. biochemistry of lipids, lab. metabolism and pathol. biochem. istituto superiore di sanità, rome, italy.

Embryonic muscle development in fast‐ and slow‐growing chickens:
role for IGF‐I and myogenic transcription factors
Sara L. Al-Musawi and Neil C. Stickland
Department of Veterinary Basic Sciences, The Royal Veterinary College, Royal College Street, London NW1 0TU, UK.
Introduction
Results: embryonic movement
Results: gene expression analyses
 Chickens (Gallus gallus) have been genetically selected for different traits: fast-growing broilers have been intensively selected and reared for high growth rate and muscle ma ss (predominantly breast muscle).
The maturation and patterning of myoblasts into multinucleated myotubes and fusion into myofibers is dependent on the tightly orchestrated activation of a myriad of myogenic regulatory factors (MRFs) e.g. myf5, Insulin-like growth factor-I (IGF-I) plays major roles in onic da -y17G
modulating skeletal muscle mass and fibre size. In ovo Figure 3. Broiler chicks expressed more IGF-I mRNA in the pectoral
administration of IGF-1 stimulates post-natal muscle Figure 3. Broiler chicks are more motile (A) and heavier (B) than layers.
muscle (A) by hatch; IGF-I mRNA only remained higher in the broilers until ED15 in the gastrocnemious muscle (B) Results: gene expression analyses
Discussion and Conclusion
To determine whether differences in muscle phenotype of Broiler chicks are more active in ovo and show raised body mass fast- and slow-growing chicks originated during embryonic development and whether such differences  Broiler chick appear to display a larger expression of myoblast were a result of movement-dependent experiences that commitment (myoD mRNA) in both pectoral and gastrocnemious drive differential MRF and IGF-I expression patterns.
Materials and Methods
 There appears to be a greater proportion of differentiated fibres (myogenin mRNA) in the broiler pectoral muscle (ED15) but more Ross (broiler) & White Leghorn (layer) myogenin in layers in the gastrocnemious at the same time point.
eggs incubated at 37.5oC with daily rotations  Great muscle growth (IGF-I mRNA) towards hatch in the broiler ni da L-17
pectoral muscle; trend not seen in the gastrocnemious muscle.
nclusion, we have shown prolonged muscle cell proliferation (also in line with histological findings) and greater extent of differentiation and growth in the broiler pectoral muscle prior to hatch. References Acknowledgements
Hammond CL, Simbi BH & Stickland NC.
gastrocnemius muscle) for histology & influences embryonic motility and growth of limb tissues in the chick (Gallus gallus). J Exp Reagents were purchased from Sigma and Qiagen Ltd. UK.
Biol. 210(Pt 15): 2667-75.
Figure 4. Broiler chicks expressed more myoD mRNA on ED15 in both muscle
Kocamis H, Kirkpatrick-Keller DC,
QuantiTect SYBR Green kit used for RT-PCR.
types (A and B). Myogenin mRNA was greater in broilers on ED16 in the pectoral Klandorf H, Killefer J. (1998) In ovo
PCR product sequences were analysed by GeneService, UK muscle (C); however myogenin was greater in the layer gastrocnemious (D) earlier administration of recombinant human insulin- One-way ANOVA and Bonferroni post hoc test like growth factor-I alters postnatal growth and (* P< 0.05 ** P< 0.01 *** P< 0.0001) development of the broiler chicken. Poult
Sci.77(12):1913-9.

Source: http://www.vetschool.bris.ac.uk/bbsrc/images/Workshop%20Posters/Al-Musawi%20poster.pdf