Q: "You said you would post this=85I hate getting flamed for asking a simple question. Why do you say modern food is so bad if earlier ferrets ate bad chow like meow mix and didn't get as sick?" A: Did I say modern kibbles are bad for ferrets? Are you sure? Oh, wait, I did say that, didn't I? Gosh, what was I thinking? Extrusion technology is actually quite simple. You place the raw ingredients into a hopper (or series of hoppers), and allow the food to be introduced into a tube, where it is transported towards a die by one or more carefully designed screws, not unlike the type used to screw two pieces of wood together, only much larger. The screw(s) mix the food and transport it down the tube to the opposite end, where it is forced out a die. Because the hole in the die is much smaller than the diameter of the tube, great pressure and heat are generated just before the food exits the extruder. As the food exits the die, the pressure drops, and as anyone who has taken basic chemistry knows, place heated water under great pressure, then suddenly drop that pressure, and the water will turn to vapor and flash off. In this case, escaping water vapor expands the dough and leaves behind a cooked, dry, hard biscuit. The same thing happens when you make popcorn: the hard outer shell contains the heated water to a point that, when exceeded, causes the outer covering to split. The water suddenly turns to vapor, expanding the interior of the corn, and flashes off, leaving behind a dry product that when salted and buttered, becomes ambrosia. Yum! The angles and depth of the screw blades are varied to produce various amounts of mixing, shear, and friction. As the screw(s) turns, the food can be mixed, compressed, heated, sheared, melted, chemically changed, and even cooked. Some of these reactions are predictable; others are uninvestigated, or even harmful. For example, under extrusion, some harmless foods can be converted in carcinogenic feeds because of specific types of oxidative reactions, reactions with exposed extruder metals (Fe, Al), formation of free radicals, and lots of other stuff only a demented biochemist would love. Inedible starch- -cellulose- -could react with various nutrients, changing the way they are absorbed into the body. Edible starches that are typically hard to digest can be sheared and fragmented, making it quite easy for the body to absorb and convert to sugar. Generally, extrusion technology causes a denaturing of protein and gelatinization of starch so that both are easier to digest. Many things are extruded (Cherrios, Cheetos, Cheese Balls), and depending on the exact process, can be extruded, remixed for additional extrusion, or even baked or fried. The temperature and pressure can be adjusted so the same die and screw produce different products. Depending on the origin of the ingredients, significant differences can exist between batches of feed made in the same extruder, under the same conditions. You cannot make a direct comparison of old extruded foods to modern ones, even if you have a list of their basic ingredients. The reason is without knowledge of the exact screw mechanism, pressure and heat in the die chamber, and turning speed of the screw (among other factors), you cannot predict the exact chemical changes done to any particular formulation. I too have noticed what might be considered discrepancies in the health of ferrets eating the crappy foods a dozen years ago compared to those eating modern formulations today. I discount the differences for the most part because of their anecdotal nature. However, some comparison MAY have value. For example, Meow Mix may have had a lot more starch included in the formulation, BUT, if that starch wasn't as gelatinized during extrusion, the actual amount of digestible starch might be LESS than in modern formulations. Excluding problems of micronutrient malnutrition (solved with supplements), Meow Mix could have actually been healthier than modern feeds because of the lowered caloric energy available to the ferret per consumed quantity of feed. The other reason I ignore the Meow Mix "phenomenon" is due to modern formulations, the source of the ingredients, changes in extrusion technology (pressure, heat, friction, shear, exposed metals, die shape, screw pitch and depth, etc.), and even the source of the water used in mixing are ALL uncontrolled variables. Because of the difficulty of controlling these factors, you can cite as many anecdotal stories as you like, it still doesn't make the feed comparable to modern feeds. Are modern diseases due to a change in formulation? Are they due to a change in extrusion technology? What about oxidative reactions with water containing reactive minerals? Are the differences in disease real, or just an epiphenomenon of poor veterinary diagnosis or awareness? Are the anecdotes valid: are the memories reflecting a true event, or just the perception of one? See the problem? Without a handle on the variables, comparisons of earlier kibble formulations are moot. Personally, I suspect Meow Mix used a lower quality (cheaper) starch which wasn't denatured as well during the extrusion process, making it less effective in converting hard-to-digest starch into easy-to-digest starch. Easy to digest starch translates as caloric energy. It could mean the early Meow Mix might have been a calorie restrictive feed compared to modern ferret feeds. As a caloric restricted (CR/DR) food, it would have extended lifespan, reduced the incidence of tumors, and helped lessen or prevented disease. Maybe the anecdotes are right, and years of feeding a crappy, calorie restrictive food is evidence dietary restriction works. It may just be another hypothesis, but at least it has theoretical and practical merit. Still, it is an unprovable hypothesis unless someone has a collection hermetically sealed boxes of the stuff for analysis, as well as access to the formulation records (origin, quality), and extruder records. Or, is it unprovable? It could be someone is investigating the issue as we speak.... Bob C [Posted in FML issue 3962]