Poultry, and chickens in particular, as this discussion will focus on broilers and layers, are omnivorous animals. This implies that they eat practically “everything,” and this includes other animals — at least in their wild state. Farmed chickens are fed diets that we design for them to be complete, balanced, healthy and productive. As such, one of the most useful sources of protein is that of animal-derived ingredients. There is not as great a number of animal proteins as in the case of vegetable proteins, but the former have some unique properties or benefits not found in the latter. In many cases, it is even possible for the protein from animal-derived ingredients to be less expensive or more readily available than vegetable proteins. So, nutritionists are often faced with the dilemma of whether they should use animal proteins.
One of the most useful sources of protein is that of animal-derived ingredients.
All-vegetable diets are naturally possible, although nutritionists must work a bit harder to keep overall protein levels low enough while keeping amino acid levels high enough to ensure bird health and productivity. This is nothing a good nutritionist cannot achieve, but an animal protein can often offer an easier solution to this minor issue. Of course, when the protein in animal-derived ingredients is locally cheaper than that in most vegetable protein sources, then an all-vegetable diet becomes a local niche market that requires smart marketing to justify the cost. As it happens, consumers today are rather positive to an all-vegetable diet fed to the animals that produce their broilers and eggs. This has been enhanced by several unfortunate incidents involving animal-derived proteins, the ill-defined notion of animals should not eat other animals, and of course, the clever marketing efforts of those who are quick to capitalize on any consumer-related misconception.
Having discussed this conflict between the nature of the bird's organism, which eats “everything” as long as it remains healthy and productive, and the current conflicted nature of consumer understanding of what is “natural” and what is not, we have a new development to consider: that of insect protein. For reasons that escape the scope of this discussion, several governments, including the European Union, actively promote the production of protein-rich ingredients from insects. How they will convince consumers that it is alright for birds to consume insect protein whereas it is not so to consume any other animal protein (because insects remain within the kingdom of animal species), is beyond my understanding, but so is the majority of topics with which politicians are involved.
Back to nutrition; if we manage to convince our consumers that animal proteins are safe and natural to use (and here we have a lot of work to do), then we need to identify the available sources and work on minimizing their problems while maximizing their benefits. The following is a brief list of available animal protein sources that can be used as a starting point with your nutritionist or nutrition supplier.
1. Insect protein
Having already started with this product, it is important to note that insect meal is rich not only in protein but also in fat. Knowing that birds, like all monogastrics, deposit the same type of fat in their fat tissue as that in their feeds, one needs to be careful to properly address public concerns about eating insect-type fat along with their chicken. Not that birds do not eat all kinds of questionable stuff in the wild, but when it is about industrial farming, consumers become rather sensitive to what could otherwise be considered as normal.
2. Poultry meal
This is a mixed bag of many things. Slaughterhouse offal, condemned carcasses and even mortalities can all be mixed, minced, cooked and sterilized, and then dried to a very low-cost product. The use of objectionable raw materials may cause adverse reactions from public and consumer groups, whereas using only first-class slaughterhouse offal can provide a solid line of defense and a final product of superior quality.
3. Meat (and) bone meal
Where it is still allowed, and when of good quality, meat meal (with or without the bones) is an excellent source of protein for poultry. This product is the end rendering result from pig and cattle slaughterhouses, and it should not contain mortalities or condemned carcasses to avoid spreading of diseases. Temperatures used to sterilize such less desirable sources of raw material usually reduce protein digestibility, making the use of such meat meal a questionable proposition.
Blood meal (whole) is infrequently available, especially in regions where blood from pigs and cattle is processed to extract plasma and hemoglobin as feed ingredients. In general, blood meal can be easily overcooked and, as such, digestibility of protein can be quite low. Otherwise, it is a rich source of protein and lysine, but it is particularly low in isoleucine, an amino acid that is not monitored regularly by most feed formulation professionals.
5. Feather meal
Hydrolyzed feathers are a rich source of protein, of low digestibility, containing ample quantities of methionine and especially cysteine — both amino acids are essential for feather formation. Overcooking is a problem, lowering digestibility, but proper hydrolyzation can provide a useful product. Quality control and moderation in its use will ensure animals do not suffer from any shortcoming from this rather unusual animal protein source.
6. Hatchery by-product
Not all eggs hatch, and layer males are not always incinerated. A mix of all this “waste” material can be processed into a dried product of excellent nutritional value as it contains materials that pose no health risks to animals or consumers. Some countries object to the destruction of male layer chicks, but they have not proposed an alternative viable solution, yet. The pet shop uptake of frozen male chicks for snakes and other such “pets” is minimal.
7. Fish meal
This ingredient requires no introduction. It has been used by poultry nutritionists for decades with excellent results when the fish meal is of good quality. In contrast, it can break even the best designed diet if fish meal is of low quality, as birds will simply refuse to eat such feed. Thus, quality is the main issue here, and quality today means expensive prices, which are hardly affordable by the poultry industry due to competition from the aquaculture industry.
Like with any ingredient, animal-derived proteins are not without problems, mainly quality and public perception. But, once such issues are addressed properly, these ingredients can be used to improve poultry feeds as they can often offer significant advantages over vegetable proteins.