Meat meal

Other names: Meat and bone meal Nutritional Characteristics:

Meat meal is a by-product of beef or swine processing, and this can be of variable composition. For each 1 tonne of meat prepared for human consumption, about 300 kg is discarded as inedible product, and of this, about 200 kg is rendered into meat meal. In the past, meat meal referred only to soft tissue products, while meat and bone meal also contained variable quantities of bone. Today, meat meal most commonly refers to animal by-products with bone where protein level is around 50% and calcium and phosphorus are at 8% and 4% respectively. Because the mineral comes essentially from bone, the calcium phosphorus ratio should be around 2:1 and deviations from this usually indicate adulteration with other mineral sources.

Variation in calcium and phosphorus content is still problematic, and the potential for overfeeding phosphorus is a major reason for upper limits of inclusion level. Meat meals usually contain about 12% fat and the best quality meals will be stabilized with antioxidants such as ethoxyquin. Some of the variability in composition is now being resolved by so-called 'blenders' that source various meat meal products and mix these to produce more consistent meat meals.

Meat meals are currently not used in Europe because of the problems they have had with BSE (Bovine Spongiform Encephalopathy). It seems as though conventional rendering treatments do not inactivate the causative prions. However, pressure treatment to 30 psi (200 kPa) for about 30 minutes during or after rendering seems to destroy prions. Parsons and co-workers at the University of Illinois have shown that such pressure treatment can reduce lysine digestibility from 75% to 55% and cystine from 65% down to 30%. If extreme pressure treatment becomes standard during rendering of meat meal, it will obviously be necessary to carefully re-evaluate nutrient availability.

Recent evidence suggests that the metabolizable energy content of meat meal, and other animal protein by-products, is higher than the most common estimates used in the past. In bioassays, ME values determined at inclusion levels of 5 -10% are much higher than those determined at more classical levels of 40 - 50% inclusion. The reason for the higher values is unclear, although it may relate to synergism between protein or fat sources, and these are maximized at low inclusion levels. Alternatively, with very high inclusion levels of meat meal, the high calcium levels involved may cause problems with fat utilization due to soap formation, and so energy retention will be reduced. Another reason for change in energy value, is that commercial samples of meat meal today contain less bone than occurred some 20 - 30 years ago. Dale suggests that the TMEn of meat meal from beef is around 2,450 kcal/kg while that from pork is closer to 2,850 kcal/kg.

Another concern with meat meal is microbial content, and especially the potential for contamination with salmonella. Due to increasing awareness and concern about microbial quality, surveys show that the incidence of contamination has declined, but remains at around 10%. Protein blends are at highest risk, because obviously a single contaminated source can lead to spread of salmonella in various blended products. One means of reducing microbial load is to treat freshly processed meals with organic acids. In many studies, it is shown that meals are virtually sterile when they emerge from the cooking chambers, and that problems most often occur with recontamination. Certainly most feed ingredients contain salmonella, however, because of the relative proportion of meat meals used in a diet, the actual chance of contamination for a single bird may, in fact, come from corn (Table 2.7).

The relative risk to an individual bird is, therefore, claimed to be higher from cereals because, even though they are not usually contaminated, their much higher inclusion level results in a greater potential risk. However, this type of argument is open to the real criticism that meat meals are much more likely to contaminate the feed, trucks, equipment etc., and that salmonella numbers will likely increase after feed manufacture. Pelleted and extruded/

expanded diets will have much lower microbial counts than corresponding mash diets.

Unfortunately, there is variability in nutrient availability of conventionally rendered meat meal, where lysine digestibility, for example, can vary from 70 to 88%. Such variability is not highly correlated with simple in vitro assays such as pepsin digestibility and KOH solubility.

Potential problems:

Meat meal should contain no more than 4% phosphorus and 8% calcium, since higher ash content will reduce its energy value. Nutrient availability is variable across suppliers, and so it is important to have adequate quality control procedures in place, and especially when there is a change in supplier.

Table 2.7 Relative risk due to salmonella from various ingredients


Relative Risk Factor





Vegetable proteins




Meat meals




Table 2.7 Relative risk due to salmonella from various ingredients

Dry Matter




Crude Protein


Methionine + Cystine


Metabolizable Energy:




2450 - 2850




10.25 -11.92







Av. Phosphorus




Dig Methionine




Dig Meth + Cys




Dig Lysine


Selenium (ppm)


Dig Tryptophan




Dig Threonine


Linoleic acid


Dig Arginine


Crude Fiber


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Pregnancy Diet Plan

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The first trimester is very important for the mother and the baby. For most women it is common to find out about their pregnancy after they have missed their menstrual cycle. Since, not all women note their menstrual cycle and dates of intercourse, it may cause slight confusion about the exact date of conception. That is why most women find out that they are pregnant only after one month of pregnancy.

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