Learning Center / nutrition

Soybean meal is the best protein source for livestock feed. It has a well-balanced amino acid ratio, high palatability and has an economical per-unit cost. However, there are several problems with soybean meal. It is a good source for lysine and tryptophane but a poor source for methionine. Methionine is a very important sulfur-bearing amino acid, essential for wool, hair and fur growth. There has been work done on the fur bearing animals (mink and fox) that soybean meal is a good protein source for them. Excessive amounts of soybean hulls (very high fiber) was not good for meat rabbits but regular soybean meal was very acceptable as a rabbit feed.

Anti-nutritive factors in Soybean Meal

Soybeans must be “cooked” or heat-treated There are several anti-nutritive factors in soybeans. Soybeans must be heat-treated at 215°F for 15 minutes. This destroys the trypsin and chymotrypsin inhibitor-protease. You still have saponins, tannins, lectins, goitrogens (thyroid inhibitors) and phylates causing trouble. Phylates are naturally occurring phosphorus and inositol compounds. Phylate combines with zinc, iron and manganese to reduce the bioavailability of those metals. It is a metal chelating factor. You can supplement with calcium, phosphorus and zinc or add the enzyme phytase to liberate the phosphorus from the phylate compound.

There are haemagglutins/lectins that vary in the effect on species. Rabbits and rats seem to be more sensitive to these red blood cell‘s clumping agents. The proteinaceous products also bind with the cells of the intestinal mucosae causing nutrient malabsorption problems. Saponins are glycosides that cause a bitter taste and have a hemolytic effect on red blood cells. Goitrogenic factors or isoflavinic glycosides can result in the enlargement of the thyroid and the reduction in thyroxine activity. Bad news for hypothryoid patients. The final problem is a headache mainly for turkey producers. Rachitogenic factors interfere with the calcification of bone -mainly in turkeys.

Soybean Meal processing

After harvesting, soybeans are cleaned and dried. Then the beans are cracked into small pieces by a corrugated roller. This prepares them for oil extraction. You have to separate the hull from the “meat”. Air aspirators, screen or centrifuges are the common ways to separate the pieces.

Then the “meat” is steam-heated to 215°F and run through a roller mill to create soybean flakes. These flakes provide a greater surface area for the solvent (hexane or ethanol) to extract the oil. The solvent and crude soybean oil is drawn off by a pump and distilled into the pure soybean oil.

The wet soybean flakes and remaining solvent must be separated. The flakes are toasted at a high temperature to improve the nutritional value. The hulls may now be added back to the flake mixture. The addition of the hulls to the flakes will lower the protein content from 49-50% to a standardized 44% protein and up to a maximum of 7% crude fiber.

The Expeller or screw-press is an ancient method. It processes no more than 20% of the seed. The seeds are cleaned, delinted, dehulled, cooked and flaked. The revolving screw inside the barrels presses out the oil. The leftover oilseed cake is cooled, then ground into a meal and can be pelletized.
Direct Solvent (hexane) method means mixing the cooked flakes in the solvent. Direct solvent meals have the best quality protein (expeller/screw press has the worst quality protein). However clean air laws require stringent leak prevention of the hexane.

Prepress solvent processing combines the expeller and direct solvent process. The cottonseed is screw-pressed and then mixed with the hexane. Either solvent system processes about 40% of the crushed cotton seed. Cottonseed meal varies from 36-41% crude protein with 12-13% crude fiber. Crude fiber levels depend on how many cottonseed hulls have been screened out.

Anti-nutritive factors in Cottonseed Meal

Cottonseed meal has a few problems too. Nutritionally, it is rich in total phosphorus but low in Calcium, Vitamins A and D, and the Amino Acids -Lysine and Tryptophane. Gossypol is the chief anti-nutritive headache. It is a great male contraceptive. Gossypol is a toxic yellow substance produced by the pigment glands. When the cottonseed is processed, the pigment glands are ruptured. You can block Gossypol’s action with a highly soluble iron/salt: Ferrous Sulfate. The other anti-nutritive cottonseed products are Tannins and Cyclopropenoid fatty acid.

There are two basic types of Sunflowers; oil and confectionary. While most sunflower seed meal will be a by-product of the sunflower seed oil industry, confectionary sunflower seeds can be used to produce a oil-seed-meal or human snack food. Most of the confectionary types are eaten by somebody, be it -squirrels, birds or humans. There are three types of oilseed sunflowers; Linoleic Sunflower, High Oleic Sunflower and Nusun Sunflower. The Nusun is a new variety available.

Sunflower meal comes in three forms; With Hull, Partially De-Hulled and Completely De-Hulled. Protein levels rise with the amount of dehulling. If completely de-hulled, the crude protein will be 28-47%. Your crude fiber content will also vary from 11% (completely de-hulled ) to 24% (whole seed). Sunflower meal is deficient in the amino acid Lysine but rich in Methionine (better than soybean meal). Tannin is the anti-nutritive factor.

Canola is the Canadian-bred Rapeseed. The rest of the world is suppose to call the grain an “Oil -Rapeseed”. Rapeseed is generally not used for humans or livestock. The oil contains Erucic Acid (human health hazard) and a toxic sulfur compound, Glucosinolate, prevents the meal from being used for feed. Glucosinolates inhibit thyroid activity. You also have Tannins and Sinapine as anti-nutritional factors (as if you needed more anti-nutritive factors!).

Erucic Acid has commercial uses in the chemical industry. The acid can be used to make Dibasic Acids, Polyethylene film additives and water-resistant nylon.
Canola was developed for food/feed consumption. Canola oil is low-erucic acid rapeseed (LEAR). It contains less than 2% erucic acid. The regular rapeseed or high erucic acid rapeseed (HEAR) contains as much as 40-50% erucic acid.

Canola Meal has less than 1% glucosinolate compared to the usual 10% in the Rapeseed Meal. Compared against the gold standard of oilseed meals-soybean meal, Canola is 33-35% crude protein and 11-12% crude fiber. It is rich in the amino acids methionine and cystine, plus the minerals calcium and phosphorus.

Linseed meal is the by-product of the Flax industry. Besides linen, the flax plant can be used for many things. The straw is used as reinforcing fibers for plastics and the seed produces linseed oil and linseed meal. It takes a bushel of flaxseed to produce 37.1lbs of linseed meal.

Linseed meal contains 34-38% crude protein and less than 10% crude fiber. It is very low in Lysine and Tryptophane Amino Acids. However flaxseed will produce a very glossy shiny fur/hair coat. It also acts as a mild laxative. The anti-nutritive factors are Linatine and Linamarin.

Peanut meal is the co-product of peanut oil. The peanut shells are broken between rollers and removed by blowers. The nuts are crushed and then pressure cooked. The oil can be removed by either one of two ways- Hydraulic or Screw-Pressing as in cottonseed meal/oil or by solvent extraction as in soybean oil/meal.

Peanut meal is guaranteed at 50% crude protein and 12-13% crude fiber. Lysine, methionine and tryptophane amino acids are low compared to soybean or cottonseed meal. It is also low in calcium, carotene and Vitamin D but a rich source for niacin and pathothenic acid (Vitamin B complex). The major anti-nutritive factor is aflatoxin.

Grain by-products include your gluten products, any wet milling by-products, distiller feeds, brewing by-products, yeast, grain milling by-products, and by-products of fruit and sugar processing. They supply a large part of the ingredients for animal feeds. You have a tremendous variety of them and they are usually local products since they are not worth the cost of shipping any great distance.

Generally the feed mill buys these by-products in small quantities from a manufacturer’s representative or an ingredient distributor. The mill may buy from one distributor / representative or use several sellers. This can reflect on the quality and freshness of the by-product.

Wet Milling By-products

Corn gluten feed (CGF) and corn gluten meal (CGM) are by-products of starch, high-fructose corn syrup (HFCS), glucose , dextrose and ethanol production.
First the corn must be cleaned. All foreign material and broken kernels are removed. The clean corn is soaked in a warm sulfur dioxide solution to soften and swell the kernels.

Then the steepwater and corn are drained and evaporated to concentrate the corn slush. When ground and mixed in a liquid cyclone to separate the germ from the kernel., it is ready to be processed into corn oil.

The corn germ is used for producing the corn oil. The kernel which contains the bran, gluten and starch is ground into fine particles and separated with a series of screens. Corn meal gluten includes the larger portions of gluten. The bran, concentrated steepwater solubles, de-oil germ, residual starch and protein are dried and pelleted into corn gluten feed(CGF).You can produce 12.5 lbs of dry CGF and 2.5 lbs of CGM from a bushel of corn (56 lbs).

For a gallon of ethanol (ethyl alcohol), you get 4.65 lbs of CGF. Corn gluten feed contains all of the crude fiber (8%) originally present in the corn. Your crude protein level of 21-23% competes with wheat bran, hominy feed, and brewers dried grain. Corn gluten meal has 60% crude protein which is comparable to soybean meal.
The nutritional problems with corn gluten feed and meal is the same as those in whole corn. It is deficient in lysine and can be contaminated with mycotoxins.

Distillers Feeds (DDGS)

This is usually a local product. Your feed mill has to be located near distillers (ethanol or liquor producers). Distillers dried grains and solubles are produced from corn, sorghum (milo) , barley, rice or rye.

Yeast fermentation of grain into liquor or ethanol (ethyl alcohol or EOH) produces a coarse grain fraction that is separated by screening from the alcohol-free whole stillage. It is then pressed and dried. The still bottoms are evaporated or centrifuged to get all the soluble particles. They may be dried (DDS or Distillers Dried Solubles) or added to the spent grains (DDGS or Distillers Dried Grain Solubles).

The solubles are excellent sources of the Vitamin B complex vitamins. The product is exceptionally palatable and digestible. It has a high methionine content which can replace higher cost soybean meal. Corn distillers solubles are 25-27% crude protein and 9-11% crude fiber. The high by-pass protein value (ruminant nutrition) of DDGS is about 160% when compared to soybean meal. So DDGS is usually used in dairy feeds, feed lot cattle and starter calves. It may be added in small amounts to other species feed (dog food) as a vitamin supplement . In horses, it is said to stimulate cellulose breakdown for higher feed utilization. Hopefully it does the same for rabbits, chinchillas and guinea pigs.

Brewing By-Products

Specialty beers are made from malted barley, wheat, rye, rice or oats. Light beers can be made from corn grits or broken rice. Traditional (German type) beer is made from malted barley.

Brewers Grain or Brewers Dried Grain (BDG) may be pure barley malt or a mixture of the other grains. Malt is produced by steeping (soaking) the grain in aerated water and controlled temperature until the grain sprouts (germinates). The germination or malting activates the enzymes that convert grain starch into fermentable sugars. The “green malt” is dried and kiln-heated to stop the enzyme activity. The sprouts and barley (or other grain) hulls are removed. The leftover “mash” is cooked in water to continue the starch conversion to sugar. This high sugar liquid is called “wort”. The wort is then strained from the solid portion. Yeast is added to the wort for fermentation into beer. The wet breweries grain or WBG can be used as feed at local dairy farms Or it can be dried into brewers dried grains (BDG). Brewers dried grains are usually guaranteed at 24% crude protein. The actual value maybe up to 28% crude protein. Your crude fiber content will range from 14-16%. The usual market for BDG is ruminant, although it can be also used for hind gut fermentation species

Yeast

Yes, yeast is a by-product of fermentation. It is a single-cell protein by-product from the beer, liquor, wine, baking and ethanol industries. Each of those industries use different yeasts to produce their products. Yeast production starts when the grain mash is cooked, separated and dried. Now called “wort”, it is inoculated with bacteria to produce lactic acid. The wort is cooked again and yeast is now added into the vats. The yeast enzymes will convert the simple sugars into ethanol. After completing the conversion of simple sugars to ethanol, the yeast cells rise to the surface of the vat and are skimmed off. The yeast is filtered and dried to stop fermentation.

Dried yeast is a low fiber, highly digestible protein (50% crude protein). Even though yeast usage must be kept low to avoid its bitter taste, it is an excellent source of the Vitamin B complex.

Grain Milling By-Products

Grain milling by-products are from the flour industry. The variation in by-products from the mill feed is driven by the demand for types of flour. Yes, there are many types of flour. Not just a difference in the types of grain used, but in how they are processed and milled into flour and by what their end use products (bread, muffins, cake, pie dough, home use,etc) are.

Wheat flour milling produces six kinds of mill feed: wheat bran, shorts, wheat germ meal, millrun, middlings and red dog. There are several varieties of wheat- spring, winter soft wheat and durum are the most common ones in the US. So your wheat mill feeds will vary. Milled rice (white rice) produces rice bran, aleurone and germ, and a rice mill by-product which is the rice hulls, some bran, polishings and the broken grains. As more varieties of exotic rice are grown in the US, variation in rice bran and rice hulls will affect the feed industry. Those by-products have to be used in some kind of animal feed.

Oat milling produces reground oat feed (oat hulls), flaked oats (like Quaker Oats), rolled oats (animal feed), oat bran and oat grouts.

Wheat and Rye Mill Feeds

Before any grain can be used for animal or people feed/food, foreign material al must be removed. To do this, you move the grain over a series of sieve screens, magnets, and separators. You use aspirators to remove the light weight materials of dust and chaff. A washer dissolves the dirt clinging to the kernel and allows the stones to sink.

You “condition” the wheat to help with the particle separation. “Tempering” is adjusting the moisture content between the outer wheat bran and kernel (inner) temperature. This helps separate the bran from the endosperm. Tempered grain is ground between ever increasing finer rollers. Each roller removes more bran than the previous one. A sifter separates the bran part from the endosperm. The endosperm goes to the flour mill for processing into flour.

Wheat bran is the coarse ,outer covering of the wheat kernel (berry as health food stores call it). It has the same nutritional deficiencies common to all grains along with the same laxative effect common to all high fiber products. Generally no more than 15% is used in a concentrate feed. The crude protein ranges from 13.5 to 15% with the crude fiber content being 12%.

Wheat shorts are the fine particles of wheat bran, wheat germ, offal from the mill tail and the dribs and drabs of wheat flour. You could say “wheat shorts” are a garbage run from wheat processing. Crude fiber can not exceed 7%.

Wheat germ meal has the seed embryo. It is protein rich ( crude protein 25-28%) and an excellent source of Vitamin E. It is used in many animal feeds and human nutra-pharmaceuticals.

Wheat middlings are similar to wheat shorts. It is usually a very fine powder made from wheat bran, shorts, germ, flour and mill feed offal (sounds like the same recipe for “shorts”). Crude protein ranges from 16-18%. Middlings may not contain more than 9.5% crude fiber.

Mill feed offal is also called wheat red dog. It is mostly the aleurone layer just under the outer bran ,plus fine particles of wheat bran, germ and flour. Your crude protein varies from 17-20% and the crude fiber is restricted to 4%.

A “millrun” is a mix of ungraded and uninspected combination of middlings and bran. Crude fiber is limited to 10 %.

Corn Dry Milling

Corn dry milling produces corn meal, grits, flour, corn oil and hominy feed. First the corn has to be cleaned and tempered to separate the endosperm and germ, then dried and cooled to separate by sifting (endosperm) and aspirating (bran).

Corn oil is expelled from the germ. The germ residue is combined with the bran and starch fines to produce hominy feed. Hominy feed has 11% crude protein, 5% crude fiber and not less than 4% crude fat. It is usually used as a dairy feed.

Rice Mill Feeds

Again ,all the foreign material (rocks, dirt, etc.) has to be removed before any processing can start. Shelling removes the rice hulls from the rough rice. Polished rice is the white rice most Americans know. To shell rice, you use friction by rotating rice against rollers going in opposite directions at different speeds. The hulls are aspirated away to be become a roughage feed. Brown rice is dehulled rice with the bran still attached. To get white rice, the bran is removed by scouring it against an abrasive roller cylinder rotating in a stationary cylinder sieve. The bran and some broken kernels are sieved out.

Milled or polished rice accounts for most of the various rice food products. Rice bran only accounts for 8% of the total rice product. It contains 12% crude fat, 12-13.5 % crude protein and can not exceed 13% crude fiber. The high fat content requires antioxidants or extremely rapid use before rancidity occurs.

There is another rice mill by-product produced from all the residual material (bran, hulls, polishings and broken rice grains). It has a low crude protein (6%) and high crude fiber content (30-32%).

Generally rice mill feeds are used in dairy feeds. They can be used in poultry and catfish feeds.

Oat Mill Feeds

Oat meal, oat flour, oat grouts, rolled oats, and oat bran are the common oat mill products. The basic preparation for processing starts with cleaning the grain and then steaming or slowly roasting to “temper” the grain.

The hulls are removed and the cooled oats are graded by size. The hulls can be removed by two large circular milling stones or by centrifuge impacts. Screening or aspiration separates the hulls, groats, and broken grains. Oat grouts can be used for feed or can be steamed and flaked into rolled oats. Rolled grouts have very high crude protein (16-17%) and low crude fiber (3%). Reground oat feed is the oat hulls. This by-product has low crude protein (5-6%) and very high crude fiber (30%). Oat bran normally goes into human foods.

When you change from packaged old hay bought from a store, to a new fresher hay such as an alfalfa bought from Oxbow, [or some other good grower/supplier] then you must remember to slowly introduce the new hay to the chinchilla over about a six week period. The reason for this is that the flora/fauna of the GI tract, the bacteria that break down the masticated hay, need to change over to handle the fresher cleaner hay. The chins will love the new stuff, and will want to “pig out” on it. The problems that ensue can be everything from bloat, to colic to fermentation of the hind gut even to death. So, when you switch hays, start with 1/5 of new and 4/5 of old, and slowly allow the animal to go to 1/5 more each week.

The same thing holds true when you switch all other types of foods. The pellets that you use the animal’s body is used to, so if you board your animal with a friend, or get a new brand of pellets, or try a new mix or something similar, remember that you have to give the GI tract bacteria time to get used to breaking down the new formula. This may only take 1 week to 6 weeks depending upon the differences, the richness, the milling etc. Again start with mostly old formula and slowly introduce the new stuff.

Remember too, if you get a chinchilla from someone you need to get a weeks worth or more of the food that the chinchilla is used to, so that you can wean them onto the new food. Chinchillas that have been shipped also tend to have a poor appetite and diarrhea from the stress of being shipped, so switching to a new food without weaning onto foods is harder on their system. You could lose a chin that way.