Note: You must be registered in order to post a reply. To register, click here. Registration is FREE!
Posting A Reply To: Food Topic (Protein)
T O P I C R E V I E W
JettPosted - Jan 19 2009 : 06:12:37 PM
I'm concerned about the 50% protein in the diet suggested in the gliderpeadia. They do not increase the protein for lactating or pregnant mothers here in the Zoos in Australia and wondered where this figure came from. I do not just want to change the amount but would love some discussion from people and would love to know where this figure orginally came from if anyone knows? Chances are a diet too high in protein could also be a health concern, so what do people think?
2 L A T E S T R E P L I E S (Newest First)
Jett Posted - Jan 20 2009 : 12:41:18 AM
It's taking me a bit to digest all this Eric, but think I can see where you are coming from and I think it makes sence, although not easily.
quote:Now, to give this some context, the original number was the absolute bare minimum for wild sugar gliders. On page 122 of Hume, it says that "females would need to supplement this [...] to meet the additional protein demands imposed by reproduction."
I also will read up on this in Hume as i wondered where this originated, as I said they don't appear to change the diets to lactating mothers here in the Zoos. Maybe I will email them to find out if this is actaully the case, just cause it doesn't state it in any of their diet sheets I'm guessing doesn't mean the individual keepers don't make changes.
Eric C Posted - Jan 19 2009 : 11:26:31 PM
How are you reading it? I think there are two possible connotations, and the intended meaning is not what's stated. 50% protein doesn't mean 50% of the diet should be protein, but that 50% of the diet should come from food sources that people would consider as a source of protein. So, perhaps it should say "50% of diet from protein sources" instead of "50% protein."
From the chicken listed in the nutrient database, and I'm just picking this as an example as it seems to be commonly used, http://www.sugarglider.com/nutrition/food.asp?ndbid=05065 Chicken is roughly 29% protein. If chicken comprised 50% of the diet, then the portion of protein consumed would be only 14.5% of total matter consumed.
Now, here is where it gets confusing, and I've yet to see an explanation of the meaning of the -0.75, but if taken in the context of dimensional analysis, we get a low number. See Marsupial Nutrition by Hume, pages 121-2. The nitrogen requirement is 87 mg * kg-0.75 * d-1. The 0.75 is common notation, but like I said, I haven't seen a layperson explanation in the event that the usage is non standard mathematically. See Kjeldahl Method in the gliderpedia for specifics, but to convert that from a nitrogen requirement to a protein requirement becomes 543.75 mg * kg-0.75 * d-1.
On the nutrient page, using the Calculator and converting 1 tablespoon to cups, we see that 1Tbl = 0.0625 cups. Copying and pasting 0.0625 to the cups serving section, we see that 1 tablespoon of chicken is 2.536 grams of protein. That's way too much, so now begs the question, what should a serving size be? A teaspoon, which is just 1/3 of a tablespoon, would be 0.845 grams.
Now, to give this some context, the original number was the absolute bare minimum for wild sugar gliders. On page 122 of Hume, it says that "females would need to supplement this [...] to meet the additional protein demands imposed by reproduction."
So, one teaspoon of chicken per glider per day may be above the minimum requirements, but I think that's a good thing. I'm not so sure that it's enough to cause protein poisoning. I don't think we will ever see any studies done on wild gliders that eat too much protein, as that's just now how things work in the wild.
I did my own nutritional analysis recently, and the daily recommended intake for protein for me was 64 to 224 grams of protein per day. That's a pretty large spread. I'm sure there will be a range and not an number for the actual protein requirements for sugar gliders. Remember, the values calculated above are based on the bare minimum values and not necessarily recommended values. We want to be higher than those numbers, not lower.
I think there is definitely room for excess in this, so portion control is important. Excess protein consumption by a glider will have a very visible side effect, the glider will get fat. Excess protein is not stored as muscle, but is metabolized and stored as adipose tissue, commonly referred to as fat.
And unfortunately, the only way to get real scientific data for an upper limit on protein intake would be to treat sugar gliders like lab rats. That will happen eventually and has already happened in a few studies where they're treated as lab rats, although none of the studies were diet related if I remember correctly.