Live or p/k vs f/t nutrition

[daver676]

This was brought up in another topic here, but I thought it deserved it's own thread.

So is p/k more nutritious than f/t?

Dave

[OttawaChris]

One would have to assume yes... freezing destroys some of the vitamins and other goodies. It also destroys cellular structure and dries out the item (not an issue for most of us though because from what I read here most people thaw in hot water anyway) The only real bonus to freezing is you can buy MUCH cheaper in bulk and you dont have to constantly be going to the store to buy feeders.

...And I am sure frozen doesnt taste as good LOL I will take a fresh T-bone over a frozen one any day wouldnt you?? ;)

[Linds]

I agree with Chris, definitely p/k items are more nutritious. Although freezing destroys some of the nutritional value, it does kill off unwanted parasites prey items may be harbouring. Frozen prey items still retain enough nutritional value through the freezing process that snakes will be adequately nourished.

[Invictus]

I think you mean f/k... both frozen and fresh killed are both still "pre" killed. :)

We have a Kenyan that will NOT take thawed mice no matter how much we beg and plead, so I have to assume it smells different. If it smells different, I have to assume that the freezing process destroys something of the mouse smell. I don't, however, believe that it ruins THAT much of the nutrition. My frozen steaks are just as nutritious as freshly butchered steaks... the fresh just smells and tastes better. :)

[daver676]

So could I maybe inject the f/t mice with some type of suppliment to ensure my snake is getting the most bang for the buck?

Invictus,

yeah, I get confused sometimes...I had a long day at work....


Dave

[Linds]

There's no real need to supplement your snake, as I said the freezing process doesn't decrease the value significantly enough IMHO. Dusting infrequently with a vitamin supplement is fine, but not necessary. As a boost, a few times a year I will inject the rodents with a wee bit of unflavoured pedialyte... they don't -need- it but it makes for a nice little electrolyte boost :)

Originally posted by Invictus
I think you mean f/k... both frozen and fresh killed are both still "pre" killed. :)


P/k is still a widely used and acceptable term for freshly killed ;)

[Ed_r]

There will be some slight nutrient loss, in feezing. But Freezing also kills most of the parasites that rodents carry. So I think the nutrient loss is well worth not having to give your snake Panacur or Flagyl(sp?) or some antibiotics.
Plus there is a huge convenience factor involved too.

The slight nutrient loss is no reason to switch to prekilled prey. Not worth it.

[eyespy]

According to Susan Donoghue's research, if I remember correctly, B vitamins such as thiamin are the nutrients most affected by freezing. Protein values on an "as fed" basis actually go up slightly. The degradation of the cell walls that occurs during freezing and thawing makes the proteins, and possibly calcium, easier to digest and more bioavailable.

[reverendsterlin]

This is from an FAO report on meat processing. Part of the study does involve carcasses but I don't think accounts for gut-load nutritional values. Hope this helps.
Food and Agriculture Organization of the United Nations (http://www.fao.org/)



Nutritional Changes by Freezing

Meat is frozen without any prior treatment, unlike vegetables which have to undergo a preliminary blanching process to destroy enzymes involving considerable loss of water-soluble nutrients. So there is little or no loss of nutrients during the freezing procedure, nor, so far as there is reliable evidence, during frozen storage - apart from vitamin E.

Proteins are unchanged during frozen storage but fats are susceptible to rancidity. Pork and poultry meat are more susceptible since they are richer in unsaturated fatty acids than other meats, and comminuted meat is also very susceptible to rancidity because of the large surface area which is accessible to oxygen.

The vitamin E is damaged because the first products of fat rancidity, hydroperoxides, are stable at the low temperature and oxidise the vitamin. At room temperature they break down to harmless peroxides, aldehydes and ketones, so that vitamin E is more stable at room temperature than during frozen storage.

The losses incurred in frozen meat mostly take place when the meat is thawed, and juices are exuded containing soluble proteins, vitamins and minerals. This is termed "dripthaw" and the amount depends on the length of time of ageing (time between slaughter and freezing), whether frozen as carcass or meat cuts, conditions of freezing and speed of thawing; it varies between 1% and 10% of the weight of the meat and is usually about 5%.

There is some loss of nutrients when the meat is cooked after thawing; results published in the scientific literature tend to measure the combined losses from the original fresh meat to the final cooked product. Unfortunately the results vary so much that it is not possible to draw conclusions.

It must be emphasised that the variations are largely due to difficulties in analysis of the B vitamins, and to differences in conditions and methodology - even results from the same laboratories are inconsistent. This is illustrated very clearly by results published from one group of investigators who examined pork loin after freezing and storage at -12°C and 24°C and subsequent cooking at regular intervals over one year for changes in thiamin, riboflavin and pyridoxine (Mikkelsen, Rasmussen and Zinck 1984). Despite constant experimental conditions analyses at two monthly intervals showed wide fluctuations, especially for thiamin, which were attributed by the authors to difficulties in analytical methods.

It was tentatively concluded after storage at -12°C and cooking that about 90% of the thiamin was retained but no firm conclusions could be drawn about other vitamins. No conclusions could be drawn about storage at the lower temperature!

For riboflavin about 90% was retained at -12°C and 100% after storage at -24°C and cooking, although these results were also variable.

For pyridoxine 80% was retained when stored at -12°C and cooked but the results were erratic.

In the same report ground beef was examined only after 1 year storage and showed 80% retention of thiamine, 85% of riboflavin and 100% of pyridoxine at both temperatures.

A summary of earlier work (Fennema 1975) suggested that losses during freezing and storage of meat and poultry for 6 - 12 months at -18°C but excluding subsequent cooking, ranged between zero and 30% for thiamin, riboflavin, niacin and pyridoxine. A survey of frozen meals analysed after freezing, storage and cooking reported losses of up to 85% of thiamin, 55% of vitamin A, 33% vitamin E, 25% niacin and pyridoxine (De Ritter et al 1974).

Little research in this area has been reported in recent years and this limited number of reports illustrates the difficulty of making even generalisations about the stability of vitamins in frozen meat products

[Classic]

Invictus: It is probley not the smell that is is discourging your Kenyan Sand Boa not to eat. The sent should still be the same but maybe a little diliuted from the hot water. I had alot of trouble with a Sand Boa awhile back and managed to find away to get it to strike. Sand boas are very sensitive to vibration. Try using a 15" pair of thongs. If you can locate your sand boa or can see it without disturbing it. Bounce the pinkie lightly on the sand in the surrounding area of the boa and gradually come closer to it and he should show interest.

[Invictus]

We tried that, classic. And I always dry-thaw mice using a ziploc bag, so it's not the hot water. I tried literally for an hour one day to get the Kenyan to take a f/t mouse using tongs and simulated movement of a mouse, but the best result was, she struck and constricted, then spit it out right away. But, she goes NUTS for fresh kill. We use the feed bucket method, and as soon as she gets the scent she is all over that mouse. :)

[Invictus]

Oh, and great article Reverendsterlin. Thanks for sharing it.

[Classic]

Sounds alot like my experience. I kept it up and eventually he ate. Maybe try thawing in water without the ziploc.

[reverendsterlin]

try stimulating immediately after finishing one fresk killed prey item with a f/t one

[Invictus]

Again, tried both. :) Fresh killed or live just seems to be the only way she will take 'em. But she has been taking f/k for quite some time. Maybe I'll give f/t another shot tomorrow. I'll let ya know if I get any success.