new research debunks trad views on nutrition

[Geena]

The central thesis, that fowls possess an effective self-selection mechanism, is not in dispute. What is at issue is the control system underlying the selection,

That looks promising, let us know what you find.

The above is the real heart of the matter. Obviously chickens (and all animals) can and do self select a proper diet in their natural habitat. The two big questions are what do you need to supply chickens with in attempt to mimic that and how much of each item. And how well will they do self selecting from what you offer them since those foods wouldn't be things that would normally be available to them in nature.

In the last study the authors were surprised that the self selection pullets even ate the vitamin and mineral mix provided because it was considered unpalatable. That surprised me too.

 

[Shadrach]

I've found some more research on grass eating @Shadrach , this time with quite a detailed analysis of what was in the specific pasture used for this research, Transfer of bioactive compounds from pasture to meat in organic free-range chickens, http://dx.doi.org/10.3382/ps/pev383 ,
and which includes reference to another paper where
"Dal Bosco et al. (2014) found that in the summer, the grass ingestion ranges from approximately 15 to 43 g of DM/d per bird according to the environmental enrichment of the pasture (e.g., tall grass or olive trees)"

I'll have a read over the weekend. Thanks.

 

[U_Stormcrow]

He just says 'lays plenty of eggs'.
Also, this is his recipe for laying hens if kept confined.

'50.1kg wheat meal
50.1kg maize meal
50.1kg other grain meal (preferably yellow maize)
50.1kg fish meal
13.6kg dried milk
9.0 ground sea shells
2.3kg salt.
Give them free access to this, and a handful each of whole grains to scratch out of their straw or litter.'

Does that seem like a lot of salt?

50 kg of fish meal???? can you recheck that???

2 parts soft wheat, 4 parts corn, 2 parts fish meal, 1 part "everything else" comes out of my calculator before moisture correction at over 23.5% Protein, 1.7% fiber, 4.7% fat, 13.33 Mj/kg (right in the middle of the range) with .6% Methionine !!!!! (yes, TWICE the recommended minimum), 1.47% Lysine!!!, .9 Threonine!, and .25 Tryp.

I'm a big fan of highly nutritious feeds, but even by my standards, and even for broilers, that's likely wastefully excessive.

 

[Shadrach]

A picture paints a thousand words, as they say, so here is one to illustrate the last point
View attachment 3433182
and yes, that is a pheasant on the extreme left. He joins the party sometimes.

Still cracks me up.

 

[U_Stormcrow]

Is it the environment or the genetics? My sister has a slow digestive system, her husband has a fast one. If he eats much of the light foods she does best with (lots of salads and fruit), he is hungry, light headed, feels (and is) empty all the way down, and such within a couple of hours. If she eats much of the heavier foods he does best with (grains, meats, fats), she feels dumpy, lethargic, feels (and is) full all the way down, and such for more than a day. Of their two sons, one is like him and one is like her in this way.

They are on the opposite extremes of the range people are but we thought maybe this concept that people can be so different is why so many fad diets have a similar pattern - an extreme diet works so wonderfully for a few that it is touted as a miracle concept. Then many try and it doesn't work for a lot of them.

Actually, I think it is both and other things too - the system working rather than isolated parts of the system. Something like not needing much fruit if the little you have has what is needed to cover the narrow gaps in the rest of the diet. Maybe it isn't "a little bit of fruit" that makes it work; maybe it is because the little bit of fruit happens to be bilberries. Or the little bit of nut have happens to be Brazil nut. Concept, here ... not necessarily the details.

a bit of both. The body has limited ability to activate, or deactivate, genes to respond to dietary intake. Over time, of course, generations in that environment will select for those with the genes to activate to most efficiently use those foods.

Like so much else, its complicated - and you are absolutely correct. What works for some does not necessarily work for all. Differing initial conditions, differing initial assumptions, differing outputs.

 

[U_Stormcrow]

And, we are finding out how VERY different everyone is!

Brains behave differently. Why not digestive systems?

be glad you don't have my brain!

and now that I have a day job, Im wishing I had someone else's digestion again. I've put on 11 lbs in 6 months.

 

[U_Stormcrow]

Other studies have found chickens eat to meet energy rather than to meet protein. It is so for cattle too. Or, at least they do if it a simple choice between the two. Some of the cafeteria choices (lots of choices each offered individually) indicate they will eat to meet other categories too.

In this study, the group that consumed 9.3% protein also consumed the protein in the alfalfa and insects and such. Since they kept the alfalfa stripped enough it didn't need clipping like the other plots did, they foraged in it heavily.

This is just math.

Depending on what the chickens have to select from, it may be nearly impossible (particularly in the short term) to meet some minimums without grossly exceeding some other targets. The quality and diversity of the offered free selection has a big impact on whether the math can be made to work.

 

[U_Stormcrow]

and THANK YOU for the links. Looks like some good reading if I have working internet.

 

[saysfaa]

"...Short periods of access to one food alone are followed by a preference for the opposite food when access to both is restored...There is evidence that growing chicks can differentiate high-lysine from low-lysine foods but do not entirely balance their diet for lysine. Methionine-deficient broilers eat more of a methionine supplemented food than normal birds, while laying hens eat some methionine-fortified food when given a choice against a low-methionine food, but not enough to support normal egg production. It is concluded that poultry can show a great degree of ‘nutritional wisdom’ as far as protein is concerned but that they need to be allowed to differentiate between foods with different nutrient profiles by sensory means, and a lack of training might account for some of the poor results obtained...."

Source

Again, I can only access the abstract. It talks of "training" elsewhere too. I don't know what they mean by training.

I'm convinced on the parts they say chickens can do; I don't see a different explanation given the consistency across studies. I am not convinced by the parts they say chickens can't do. Among the possible explanation is that there is something else being balanced.

Edit to add:
The source is

Diet selection for protein by poultry​

JM Forbes, F Shariatmadari
World's Poultry Science Journal 50 (1), 7-24, 1994

 

[U_Stormcrow]

"...Short periods of access to one food alone are followed by a preference for the opposite food when access to both is restored...There is evidence that growing chicks can differentiate high-lysine from low-lysine foods but do not entirely balance their diet for lysine. Methionine-deficient broilers eat more of a methionine supplemented food than normal birds, while laying hens eat some methionine-fortified food when given a choice against a low-methionine food, but not enough to support normal egg production. It is concluded that poultry can show a great degree of ‘nutritional wisdom’ as far as protein is concerned but that they need to be allowed to differentiate between foods with different nutrient profiles by sensory means, and a lack of training might account for some of the poor results obtained...."

Source

Again, I can only access the abstract. It talks of "training" elsewhere too. I don't know what they mean by training.

I'm convinced on the parts they say chickens can do; I don't see a different explanation given the consistency across studies. I am not convinced by the parts they say chickens can't do. Among the possible explanation is that there is something else being balanced.

I'm convinced that making a balanced, nutritionally complete, feed from a relatively small number of ingrediets is HARD. Even with a spreadsheet and some modern mathematical "tricks" - like matrix multiplication and multivariable algebra.

Honestly, I'm somewhat comforted that the chickens aren't better at it than I am.