Appetite regulating genes may contribute to herbivory versus carnivory trophic divergence in haplochromine cichlids
- Published
- Accepted
- Subject Areas
- Developmental Biology, Evolutionary Studies, Genetics, Molecular Biology, Freshwater Biology
- Keywords
- Appetite regulation, East African Lakes, Cichlids, Gene expression, Trophic specialization, Adaptive radiation, Anorexigenic, Orexigenic, Brain, Larval development
- Copyright
- © 2019 Ahi et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2019. Appetite regulating genes may contribute to herbivory versus carnivory trophic divergence in haplochromine cichlids. PeerJ Preprints 7:e27865v1 https://doi.org/10.7287/peerj.preprints.27865v1
Abstract
Feeding is a complex behaviour comprised of satiety control, foraging, ingestion and subsequent digestion. Cichlids from the East African Great Lakes are renowned for their diverse trophic specializations, largely predicated on highly variable jaw morphologies. Thus, most research has focused on dissecting the genetic, morphological and regulatory basis of jaw and teeth development in these species. Here for the first time we explore another aspect of feeding, the regulation of appetite related genes that are expressed in the brain and control satiety in cichlid fishes. Using qPCR analysis, we first validate stably expressed reference genes in the brain of six haplochromine cichlid species at the end of larval development prior to foraging. We next evaluate the expression of 16 appetite related genes in herbivorous and carnivorous species from the parallel radiations of Lake Tanganyika, Malawi and Victoria. Interestingly, we find increased expression of two anorexigenic genes, cart and npy2r, in the brain of carnivorous species in all the lakes. This supports the notion that herbivory compared to carnivory requires stronger appetite stimulation in order to feed larger quantity of food and to compensate for the relatively poorer nutritional quality of a plant- and algae-based diet. Our study contributes to the limited body of knowledge on the neurological circuitry that controls feeding transitions and adaptations and in cichlids and other teleosts.
Author Comment
This is a submission to PeerJ for review.