the natural chicken: Synthetic methionine in commercial feed... Is it safe?

Tuesday, January 4, 2011

Synthetic methionine in commercial feed... Is it safe?

DL-methionine (the synthetic version) is so ubiquitous in chicken feed that organic chicken producers are having a hard time finding a natural replacement.

Adding synthetic methionine is cheaper than adding natural protein. This is why modern chicken feedstuffs rely on it. In other words, it's purely about industrial scale production. Yet the practice also seems to have percolated down to backyard chicken feeds.

Methionine is one of the crucial building blocks of life. According to the Evonik website (http://history.evonik.com/sites/geschichte/en/chemicals/inventions/degussa/methionine/pages/default.aspx), DL-methionine came into widespread use from 1974-7, but had first been synthesised decades earlier as a way to combat nutritional insufficiencies in soldiers.

The question is whether there is a difference in metabolic terms between synthetic methionine and natural forms.

As it happens, there is. You see, DL-methionine contains both the naturally occurring isomer of methionine (L) and its mirror image (D) in equal ratios. But only L-methionine can be utilised to make animal protein. To be used in the body, D-methionine (half the DL) must be converted to L first, and this conversion is not 100% but around 90% in chickens.

What happens to the extra 10%? Well if you read what happens in calves, it seems likely that it results in elevated plasma methionine: ‘Although the unnatural D-isomer of methionine can be used efficiently by growing calves for protein deposition[…], it leads to higher concentrations of plasma methionine than does the natural L-methoinine[…]’ (See J. P. Felix D'Mello, Amino acids in animal nutrition, CABI publishing, UK, page 341.)

If the use of DL-methionine has a tendency to raise methionine plasma levels in calves, then it stands to reason that carcasses of DL-fed broilers could easily contain traces of D-methionine. This substance is not well used in humans. (See:
http://www.ncbi.nlm.nih.gov/pubmed/1138025)

As it happens, excess dietary methionine is also associated with artherosclerosis. The excess methionine artherosclerosis association seems to exist whether or not there is also elevated homocysteine (a subsequent product of methionine, normally described in association with artherosclerosis). While the source for this paragraph doesn't discuss different isomers of methionine, it's worth wondering to what extent methionine excess occurs after ingestion of D isomers? See
‘The atherogenic effect of excess methionine intake’ at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC299913/

Needless to say, DL-methionine seems to have adverse effects on the chickens themselves. In 'Effect of herbal or synthetic methionine on performance, cost benefit ratio, meat and feather quality of broiler chicken' (see * below for the extended citation), Halder and Roy set out to compare performance between a control group fed no added methionine, a group fed DL-methionine (the synthetic form), and a final group fed a natural version (herbal-derived methionine).

In general, performance between both methionine-supplemented groups was similar (being above the unsupplemented group), but liver triglycerides were noticeably higher in the DL-methionine supplemented group than in the natural-methionine supplemented one, and the livers in synthetic supplemented birds were larger as well. In their words: '[...]supplementation of HerboMethione^® in diets decreased liver triglyceride markedly when compared to bird fed DL-methionine (synthetic) supplemented diets.'

Of course, liver triglycerides are associated with heart disease, among other problems. The DL-methionine fed birds were also slightly lower in carcass muscle but higher in carcass fat than the natural methionine fed group.

Interestingly, the DL-methionine group also had a higher death rate than either the unsupplemented or natural methionine supplemented groups, though the study authors state that most deaths overall were accidental. As a side note, subtle neurological damage typically produces increased rates of accidents in humans. Chickens might not be intellectual superstars, but I'd like to see a study on the use of synthetic methionine in relation to neurological health.

When it comes to feeding the home flock, or for that matter feeding our children, I feel we backyarders are over a bit of a barrel. We either trust that science is on top of these questions, or, looking at the increasing prevalence of modern mystery syndromes, suspect that we've been playing a long-term guessing game.

All the more reason to go back to dual purpose utility breeds and aim for a natural diet. Remember, variety covers a host of sins, and will help keep ahead of deficiency. After all, wild chickens don't base their entire diet on a couple of staples like wheat and soy. And in 'olden days' (pre-1950s) chickens got by quite well on non-synthetic diets because they included milk and milk byproducts as well as other methionine sources. See http://attra.ncat.org/attra-pub/methionine.html.

* For the study quoted in my main text, see Halder, G. and B. Roy, 2007. Effect of herbal or synthetic methionine on performance, cost benefit ratio, meat and feather quality of broiler chicken. Int. J. Agric. Res., 2: 987-996.

DOI: 10.3923/ijar.2007.987.996

URL: http://scialert.net/abstract/?doi=ijar.2007.987.996

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Home-mixed feed recipes

Just thought I'd put up an abbreviated version of one of my recent posts up as a permanent reference. The recipes in it are close to what I do.

In Modern Poultry Husbandry by Leonard Robinson, published in 1948 in London by Crosby, Lockwood and Son, Robinson includes many recipes for confined and ranged birds. Unlike some earlier books these recipes were actually tested during feed trials.

What makes these recipes so useful now is that they were formulated after nutrition science had started to take off, but before the feed industry had perfected using cheap byproduct meals 'fixed up' with the addition of synthetic vitamins and medications.

Of skimmed milk, he says: 'Where skimmed milk is readily obtainable it should be given to the chicks to drink ad lib. In that event no other protein concentrate is necessary.' (My emphasis, pages 308-309.) Modern chicken forum experts often claim that 'chickens are lactose intolerant'. However this may perhaps hold true only where pasteurised, homogenised milks are concerned.

The first recipe is Robinson's chick mash (page 318). He's written it all in pounds (lbs) and pints, but it should be fairly easy to turn these into percentages.

20 lb Bran
30 lb fine middlings (wheat milling byproducts: whatever's scraped up after milling)
24 lb maize (corn) meal
10 lb ground oats
6 lb skim or buttermilk (presumably dried)
5 lb meat or fish meal
5 lb yeast
half lb salt
2 lb limestone flour
1 pint cod liver oil.

Now some personal comments: the first being that if you make up the skim milk then sour it, you can omit (in my view) the yeast.

Secondly, as Robinson notes, if the birds have access to grass and sunlight, you can omit the cod liver oil. Most types of leafy greens will be just as useful as grass here.

You can also replace 5% of the bran with alfalfa (lucerne) meal; indeed I would do this in preference to using just bran.

I would also add some ground sunflower seed (say 4%) in replacement of some of the mix, but that's just my own preference. Robinson is quite clear that the above recipe will work.

Now his layer mash (page 320). As with the chick recipe above I would sour the milk as kefir so I could delete yeast (which is very expensive), and add ground or whole sunflower seeds. Robinson makes it clear that the recipe below presumes access to fresh grass and sunlight, and ad lib shell grit.

20 lb bran
40 lb middlings
20 lb maize (corn) meal
10 lb ground oats
10 lb meat-and-bone or fish meal
half lb salt

Easy, huh? Middlings by the way are perhaps hard to find unless you live near a mill. Far better than either middlings or bran would be to freshly grind whole wheat and include it in the mix at the same percentage of both combined. Or you could do as I do, and swap 'middlings' for the easier-to-obtain pollard when birds are young, adding sprouted wheat as the birds become able to tolerate larger particle size. I believe sprouting is the best way to retain (and indeed enhance) wheat's vitamins.

If there is no access to grass, then you'll need to add leafy greens in some form, and if sunlight is hiding for half the year you'll have to add cod liver oil. But as I see it, these are fairly simple recipes.

One last recipe from the book (page 323): the war diet for chicks. It's simple as hell, though it's advised to peel potatoes first. I've never tried this diet, so I'm not saying it's ideal, but it's worth jotting down as backup.

80 lb potatoes (cooked, obviously)
20 lb middlings
3 lb white fish meal (presumably any fish meal would do)
2 lb dried yeast
0.4 lb cod liver oil
half lb chalk (Warning: in those days, chalk was calcium carbonate; these days it's something else...).

Again, I think you could replace the dried yeast with an equivalent amount of dried skim milk, then just before mixing you would sour the milk (for B vitamins) and use it as the only liquid in the mash. Of course you'd ignore 'chalk' and use equivalent calcium carbonate powder or crushed shell.

I would also suggest adding seaweed meal to all these mixes. The high mineral content of seaweed, while in some ways unbalanced (e.g. massive amounts of iodine in some seaweeds) should help offset some of the soil mineral depletion that's gone on since these feeding trials were done.

cold brooding caveats...

A few warnings... Please also see 'Making adjustments to a cold brooder' underneath the how-to, as it adds important information about adjusting the brooder as chicks grow.

1. Slow feathering breeds will ALWAYS require a longer period to feather up than fast feathering birds. My experiences relate mostly to fast featherers like leghorns.
2. You can't cold brood low numbers of chicks in cool weather as they don't have enough combined body warmth. Fifteen is the minimum number of chicks to cold brood if the weather might be cool; 50 chicks is better!
3. In hot weather chicks trapped in a cold brooder 'igloo' may overheat. Keep an eye on the daytime weather gauge whenever chicks are shut into the 'igloo'.
4. Chicks still need to be started on a lamp for at least 2 days after hatch. This gives them time to fluff up and learn to eat and drink.
5. Cold brooded chicks need to be shut in the 'igloo' and only let out to feed and drink about 6 times daily until they learn where to go when cold. This can take a week or longer.
6. The 'igloo' section needs to be just the right size for the number of chicks. If you build the mesh circlet just large enough for the maximum number of chicks you'll be raising, and with enough head height to suit 3 week old chicks, then you'll need some way of reducing the 'igloo' size in the early days of brooding. Please see the note 'Making adjustments to a cold brooder' below...
8. Always make sure hay is stuffed loosely around the nest area so the box remains ventilated.

Making a cold brooder: 2.

Make an 'igloo' of mesh (plastic is good), and if you need to stiffen the edges, you can attach it to a circle of fencing wire or similar. Cut a door the same size as the one in the box. You also need to give your mesh circlet a roof of mesh (held together here with snipped cable ties). Important note: if you want to use your cold brooder with a lamp at times, you need to make the roof of the 'igloo' out of metal mesh. Thus you can rest a low wattage lamp directly on top of the igloo for use during the daytime, on cold days. I do this with an infra red lamp in the early days so the young chicks get the hang of where to go when cold. Another important note! The size of this inner 'igloo' part of the brooder needs to be right for the number of chicks (cosy and snug) while still allowing adequate room between 'igloo' and wooden box to stuff enough insulating material. I made my mesh circlet the right size for 30-40 chicks, but in practice I usually end up brooding 15-20. For this reason I have to reduce the 'igloo' size to start with, then increase the area inside as chicks grow (I do this with extra litter: see 'Making adjustments to a cold brooder' below). However if you're brooding the maximum number of day-olds in your 'igloo', you'll need to make a couple of larger replacement 'igloos' and make sure when attaching the mesh circlet to your wooden box that the clips are removable.

Making a cold brooder: 3.

Here is the mesh circle (which I call the 'igloo' part) attached to the wooden box-frame at the doorway. Note: I haven't shown the vent holes, but you definitely need them. Drill 4 holes per side (except the side with a door, which only needs 2) near the top of each box side, about 1.5cm diameter per hole. This cold brooder is basically ready for use (once the holes are drilled). All you have to do is stuff hay or pine shavings loosely around the outside of the mesh 'igloo', and add some inside the igloo as a floor. The unit is meant to be used in a rat proof area, or you can make a heavy duty wire roof if you want to (and a wire-roofed run attached to the front).

Making a cold brooder: 5.

The last two components in cold brooding are a piece of material draped over the top of the wooden box to keep the heat in, and an attached run.

Firstly for the material: my old book suggests a hessian sack. As it's hard to find hessian sacks these days, I use a doubled-over old, ratty bath towel, or only a single layer if the bath towel is still fairly thick. (Don't tell my husband where our towels disappear to.)

The drape is absolutely vital; without it chicks will chill and die.

If the drape is too heavy, it won't breathe. Actually the best drape, I've found, is a purpose-knitted woolen blanket the right size for the box. You may have other suitable materials. Don't drape over the vent holes in the box sides if you can help it, and make sure no predator can get into the brooder shed to pull the drape off during the night, or chicks will chill (I've had that happen, though luckily I checked the chicks in time).

Now for the run: I use a 1m long wood-sided hutch, about 20cm high, and built at the *same width* as the brooder box so chicks can't miss the all-important igloo doorway when looking to get warm. All feed and water containers are kept out here in the run.

Making a cold brooder: 6: How to use the brooder.

You can cold brood from about day 2, and I've done this successfully in temperatures down to 3C, but there's a definite art to it!

Newly hatched chicks don't know that the igloo is their lifeline. Furthermore, their first couple of days under a lamp teaches them that light and heat go together. This is dangerous when cold brooding as the opposite is true: darkness and warmth are what you want chicks to associate. Thus every time you combine the cold brooder with a lamp, you make it harder for chicks to learn to go into the igloo when the lamp is removed.

Sunlight (which you want for chicks to manufacture vitamin D) can also complicate the issue. It doesn't take long for chicks to associate sunlight with warmth, and this can make them huddle at the wrong end of the run, away from the igloo. Once the sun goes behind a cloud, these chicks can chill.

For these reasons it may be best to use this brooder away from any direct light, and focus on training chicks to use the igloo.

For the first week or so, this means keeping young chicks locked into the igloo and letting them out for 20 minutes six times a day to eat and drink, then laboriously putting them all back inside and shutting them in. It's time-consuming, and it's probably the reason why cold brooding isn't so popular these days, but it does work: chicks brooded this way, without direct sunlight to complicate things, do learn to use the chick igloo in about a week, after which they're virtually self-maintaining (except for food, water and hygiene, of course). Even so, you need to remain watchful once the chicks seem to have learned where to go, as a couple of hot days when the brooder run is nice and warm can interrupt their education (making them think outside is the place to be). This is why I say 'there's an art to it'.

Of course, another way to use the cold brooder if you're busy is to apply a low wattage globe during the day, and only cold brood at night. The cold brooder is still useful because it cuts down massively on the wattage globe used (and also there's no lamp at night).

However bear in mind that using a light (whether infra red or incandescent) tends to make it harder for the chicks to associate going into a dark 'igloo' with getting warm.

Making adjustments to a cold brooder

It's vital to increase igloo size as chicks grow. However if you've made the unit above, that's had to do.

The solution is to make the inner mesh circlet removable, and replace it with another bigger one as the chicks require more room, also gradually removing insulating material between nest and box.

Another way to do this (if you've made the igloo big enough to suit all your chicks at the age at which they'll stop needing it) is to start with the igloo itself stuffed with extra hay and floor litter. As chicks grow, you gradually remove this extra bulk.

However in practice it's hard to stop the floor litter and extra hay being scratched out. Since it's tedious to stuff it back in the igloo every night when you put chicks away (and they can also dislodge it during the night), it's best to add a small extra offcut of igloo mesh that will help press and hold the litter against the inner igloo walls. Tether this to the igloo mesh using twist-ties, making sure any stray ends of wire poke *out* of the igloo, not in! This will keep the hay against the walls and you can simply remove the offcut and the extra hay when chicks are bigger.

In the early days of brooding, I also raise the floor with padded foam (not styrofoam) and put litter on top to make sure chicks are snug against the ceiling at night.

Close-up of the nesting area.

You can see I'm currently using a lamp, as these chicks have been a bit slow to learn (most other chicks I've brooded learn where to snuggle much more quickly). You'll notice I've stuck a little spare hay on the outside of the nest area roof for extra insulation, as today was chilly. At night I'll still turn the lamp off and lay a towel or sack on top of the nest area, allowing the sides to breathe. If you look closely you can see a few holes drilled in the foam-stuff I've used as walls inside the mesh.

Close-up of the pop-hole.

I haven't yet installed a door, but a handful of hay stuffed into the doorway is fine for chicks at this age. They help themselves out of a morning, and are slowly learning to scurry back inside if it's too chilly out! But we're currently experiencing a cold snap, so I'm giving them a couple of hours of light per day. Note: while this brooder might look difficult to make, it was easy to bend the mesh (Bunnings compost panels cut to size) and join them with c-clips. Get yourself a c-clip bag and set of pliers! They're the chook keeper's best friend.

What vitamins do chooks need?

Below is a rough list of what vitamins chooks require, and the most likely natural sources for anyone mixing a complete diet. Of course chickens free ranging over insect-rich ground supply many of these vitamins from wild food.

The list below also doesn't include minerals or protein, the other essentials of a balanced diet.

Vitamin A and beta-carotene: LEAFY GREENS.

Vitamin B1 - thiamine: SUNFLOWER SEEDS, WHOLE GRAINS.

Folate: LEAFY GREENS LIKE SPINACH, WHEAT GERM.

Vitamin B2 - Riboflavin: MILK, LEAFY GREENS, NUTS, YOGHURT.

Vitamin B3 - Niacin: YEAST, BEANS, SUNFLOWER SEEDS.

Vitamin B5 - pantothenic acid: LIVER, FISH, WHOLE GRAINS, PEAS.

Vitamin B6 - Pyroxidine: CHICK PEAS, OATS, BAKED POTATOES, WHOLE GRAINS.

Vitamin B12: FISH, DAIRY, BEEF (E.G. BANDSAW DUST FROM BUTCHER).

Vitamin D: SUNLIGHT, FISH OIL.

Vitamin E - tocopherol: GRAINS, WHEAT GERM, SUNFLOWER SEEDS.

Vitamin K: LEAFY GREENS, DAIRY, MEAT.

Biotin: CEREALS, LEGUMES, NUTS.

Why do we need another chicken blog or forum?

Tuesday, January 4, 2011

Synthetic methionine in commercial feed... Is it safe?

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What vitamins do chooks need?

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