There is a striking inverse relationship between intestine length and algal nutrient content among populations of T. brichardi, suggesting substantial plasticity in response to food quality,
and thus a strong dietary influence on patterns of intraspecific variation.
Diet is a strong predictor of intestine length at both intra- and interspecific scales, indicating
that fish adjust their phenotype to balance nutritional needs against energetic costs. Furthermore, functional explanations for trophic diversification of cichlid fishes in the African Great Lakes have long focused on jaw structures, but our results indicate that intestinal plasticity in response to diet quality may also be an important mechanism for accommodating trophic shifts during evolutionary radiations.
Our use of nitrogen isotope data to
distill the complexity of tropical fish diets into a single axis
of trophic position provides the first quantitative evidence
that gut length varies in a continuous fashion as a function of
diet. These results suggest that intestine length in cichlids
reflects a trade-off between maximizing nutrient and energy
absorption and minimizing the energetic demands of digestive
The nutrient content, energy content and digestibility of
food resources all influence the overall quality of an animal’s
diet. As these components of food quality are often correlated
(e.g. low-nutrient, low-energy, high-fibre plant material
vs. high-nutrient, high-energy, easily-digestible animal tissue),
their relative influences on intestine length are difficult
Again, this paper clearly shows just how adaptive wild Rift Lake cichlids can be when it comes to their diet, and demonstrates just how great intestinal plasticity can be in response to diet quality of various species of fish found in Lake Tanganyika. As the quality of diet changes, so does the length of the fishes intestines. Remarkable information that was not available many years ago when many of the "experts" were speculating on what types of foods cause dietary issues (such as bloat) with various species of cichlids.Second, intestinal plasticity has been demonstrated experimentally in perch (Olsson et al. 2007), prickleback fish (German et al. 2006) and Tropheus (P.McIntyre
and Y. Vadeboncoeur, unpublished data), and observations in Lake Malawi cichlids suggest shortening of the gut in mouthbrooding females that are unable to feed regularly (Reinthal 1989). More generally, plasticity in internal organs in response to environmental stimuli has been documented in many vertebrates (reviewed in Piersma & Lindstrom 1997; Starck 1999), including fasting snakes (Starck & Beese 2002), migrating birds (Karasov et al. 2004) and rodents in fluctuating environments (Naya, Bozinovic & Karasov 2008), and the physiological mechanisms underlying gastrointestinal plasticity are well understood in several taxa (Starck 2003).
Thus, we believe that the observed variation in T. brichardi
intestine length is a largely plastic response to differences in
the nutrient content of their algal diet.
Both our broad phylogenetic survey and our intraspecific
comparisons suggest that the intestine length of Tanganyikan
cichlids is determined in large part by diet quality.
Thanks RD,Hey Russ, sorry to hear about your alpha male, hopefully he pulls through!
Pipette throat method? Boy, I am in uncharted territory. Any guesses on dosage?At this point I honestly don't know if epsom salt is the answer? You could dump a couple of cups into the 55 gallon tank, that may help as act as a purgative agent. But as far as nuking the parasites, if it was my fish I would probably try getting the Metro solution into its gut. Once these parasites travel beyond the intestine, into the blood stream, and/or various organs, epsom salt alone may or may not be effective at totally eradicating the parasite. In more advanced cases I think that getting metro absorbed into the bloodstream may be the most effective manner in which to proceed.