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katherine-medina

Effects of experimental increase in insulin-like growth factor 1 on feather growth rate... - 0 views

journals.biologists.com/...ental-increase-in-insulin-like

birds biology HSR2023 insulin plumage feathers molt

shared by katherine-medina on 10 Jul 23 - No Cached
  • In mammals, IGF-1 also induces the proliferation of hair follicles and inhibits apoptosis, and therefore helps to keep them longer in the active (so-called anagen) phase and delay their transition to the regressive (catagen) phase
  • while a recently published study indicated a positive relationship between plumage quality, feather vane length and IGF-1 in a passerine species
  • Detailed quantification of the moulting stage was achieved by scoring the moult of the primary wing feathers and tail feathers on a scale of 0–5, using the standard protocol for recording the progress of feather growth as suggested by the British Trust for Ornithology and further described in
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      I had no idea one could predict when a bird will molt.
  • ...10 more annotations...
  • As a result, 2 weeks after treatment, IGF-1-treated birds were in a more advanced stage of moult than controls
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      Interesting
  • In the longer term, IGF-1 treatment altered the intensity of moult: 2 weeks after treatment, control birds were moulting fewer feathers than at the start of the experiment, while IGF-1-treated birds showed the opposite pattern and increased the number of feathers being moulted simultaneously, albeit with substantial individual variation
  • We manipulated IGF-1 levels using an injection of poly-(lactic-co-glycolid acid) (PLGA) microspheres prepared by S.V.-K. and B.A.G. as described previousl
  • For example, stressors may cause a decrease in circulating IGF-1 levels (Tóth et al., 2018), and it may not be beneficial if that would affect the growth rate or the size of the developing flight feathers.
  • The fact that the growth of the tail feathers was also unaffected by the manipulation is more surprising as they are sexually selected ornaments in this species
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      Wow, I wonder why it had no effect on the growth of the tail feathers.
  • espite the robust lack of effect on feather growth speed, IGF-1 treatment maintained or even increased the number of feathers moulted simultaneously within 2 weeks, while the number of simultaneously growing feathers dropped in controls within the same period
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      Cool
  • In contrast to hair, the number of feather follicles that produce wing and tail feathers is small and shows no variation within species
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      I had no idea.
  • Some species, however, moult several wing and tail feathers simultaneously, which also applies to the bearded reedling
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      Why do some species of birds molt more feathers at the same time than others.
  • . Protein synthesis in tissues, for example, is partly promoted by and regulated through IGF-1 and this might also be of importance during the growth of feathers, in particular considering the increased demand for proteins during moulting
  • The interaction of corticosterone and IGF-1 has been suggested to predict fitness in growing songbirds (Lodjak et al., 2016). Corticosterone levels are known to have a seriously detrimental effect on growing feathers
    • katherine-medina
      katherine-medina on 10 Jul 23
       
      How does corticosterone and IGF-1 interact?
  • katherine-medina on 10 Jul 23
     
    A study about the effect of insulin on the growth of feathers.
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