deciphering nutritional values on caudata culture

[merk199]

Ok I am trying to decipher the nutritional values off the chart on caudata culture. I keep hearing earthworms/night crawlers are the best nutritionally, which I can see on the chart and that makes sense. I have also heard that blackworms are good nutritionally. But when I look at the chart they do not look so good. Am I missing something here? Also I thought crickets were nutrtionally poor unless dusted which the chart seems to confirm. But how are pintip crickets a healthy source? Are the numbers on the chart dusted for the pintips?

 

[SludgeMunkey]

aFor pinhead crickets, the calcium and phosphorous values shown are taken from a different reference than the data for adult crickets; Reference 1 reported values for pinheads being similar to those of adult crickets.

Crickets are a tricky bunch, regardless of developmental stage. "Dusting" while commonly quoted, generally refers to food for terrestrial reptiles in my experience.I believe that the CC chart quoted above refers to the fact that many different people feed their crickets many different things and to many different things.While there is some debate even now on the topic of "gut loading", this reference (http://www.nagonline.net/Technical Papers/NAGFS00397Insects-JONIFEB24,2002MODIFIED.pdf) from the CC chart bibliography explains it much better than I ever could. It really is a good read. It appears to me that at least one sample group of pinhead crickets used in the analysis were most likely fed a high calcium diet.

Quite a few references show evidence that calcium gutloaded diets for reptiles are beneficial with proper lighting and phosphorus content. As a food for caudates, calcium gut loading is generally not needed. It is best to judge a food based on the ratio of calcium to phosphorus however, and more details can be found on this topic in CC!

(following paragraphs are anecdotal and unsubstantiated, they are opinion and should be taken lightly)

As for crickets being nutritionally poor, I feel this is dependent on what they are being fed to, Axolotls would not normally consume crickets or other terrestrial insects in the wild. Their digestive tracts do not handle chitinous exoskeletons very well. They would have access to many types of worms and aquatic invertebrates. Tiger salamanders probably eat quite a few crickets in the wild, given both animals have a penchant for dark subterranean spaces. However, one really must think: Would a tiger eat nothing but crickets in the wild? Would an Axolotl eat nothing but Tetramin Turtle Stix? This is why a varied, balanced diet should be fed.


As for blackworms vs. earthworms, it really boils down to availability for may people. When I lived in Southern California, blackworms were very easy and cheap for me to get, earthworms were not. Now that I am in the Midwest, I harvest free caudate food right out of my yard every time it rains. Try and get blackworms in any form here and people do not even know what you are talking about.

 

[Ed]

Crickets are a tricky bunch, regardless of developmental stage. "Dusting" while commonly quoted, generally refers to food for terrestrial reptiles in my experience.

It depends on the supplement dusting the cricket. I've used some supplements and had aquatic caudates such as Cynops cyanurus take the dusted cricket off the top of the water so depending on the animal there are probable benefits to the consuming animal.

I believe that the CC chart quoted above refers to the fact that many different people feed their crickets many different things and to many different things.While there is some debate even now on the topic of "gut loading",

There is more argument over what "gut loading" actually means than the actual practice. Gut loading is actually a techical term that in the peer reviewed literature means one thing and one thing only... a diet that is fed to an invertebrate in an attempt to modify the calcium to phosphorus ratio of the invertebrate. A comprehensive review of the literature both historical and current with specific reference to crickets indicates that this is possible but requires strict controls and causes a high mortality in the crickets (the crickets have to be offered the high calcium diet as the only food source (not even fruit as a water source) as they would prefer to eat anything else but the diet for a minimum of 48 hours at kept as close to 80 F as possible. The crickets have to then be fed out before 72 hours as the crickets start to die from the high calcium diet after that point.
In the hobby, gut loading means that you have fed the crickets some diet that you percieve to be nutritious to the consuming animal before feeding out the crickets. This does have some value as crickets on analysis have been shown to be lacking in nutrients and allowing the crickets to feed for 48 hours allows the crickets to replace the nutrients that were lost. As a consequece there are a multitude of gut loading diets.. few if any have had the crickets analyzed to demonstrate what nutritional value they are providing to the consuming animal....

As for crickets being nutritionally poor, I feel this is dependent on what they are being fed to, Axolotls would not normally consume crickets or other terrestrial insects in the wild. Their digestive tracts do not handle chitinous exoskeletons very well. They would have access to many types of worms and aquatic invertebrates.

There is new analysis out that indicates that the amount of chitin in all of the analyzed insects has been overestimated by a factor of as much as 5 times. In addition, I am surprised that people consider crickets to have more chitin than say a dragon fly larva, or diving beetle. I have a hard time believing that axolotls would have a significantly different digestive tract than other padeomorphic Ambystoma (see for one example the reference http://www.jstor.org/pss/30054443 )

Oddly enough amphibian nutrition is something of an interest of mine and I have been refining what I know for awhile now...

Ed