Category Archives: Food

Nutrition 101

Humans have over 10,000 taste buds, chickens 20-30. As a poultry nutritionist I do not worry that the chickens will not like the taste of the feed, I worry that because the only feed they get is from the recipes I make that the feed meets all their nutritional needs. As in humans, chickens require energy, protein, vitamins, and minerals of which all are referred to as nutrients.

In chickens The Canadian Food Inspection Agency sets the regulations for the ingredients that can be used in feed. CFIA has the Feed Regulations with Schedules IV and V. These schedules are lists of ingredients that have been evaluated and approved by CFIA for manufacture, import, and sale for use in livestock feed in Canada. Schedule IV is divided into several classes of feed ingredients (energy or protein ingredients, vitamins, and minerals) with detailed descriptions, standards, and labeling requirements.

All ingredients contain protein, energy, vitamins and minerals but all are different as to the levels of these nutrients that they provide. The main function of corn, wheat, and fat in poultry feed is to provide energy. For the western provinces, wheat is the main energy source vs. in the east, and in the United States, corn is the main energy provider. Why the difference? In Alberta and Saskatchewan wheat is the main crop grown, Manitoba grows both corn and wheat, and in Ontario corn and soybean meal are grown locally. This answers the question of why some chicken is yellow and some white. Corn has pigments called xanthophylls which are responsible for the yellow color of the chicken in Ontario and the United States. Energy level of all ingredients is measured in kilocalories (kcal). Because the grains can only supply a certain level of energy and we have to also be able to meet their protein, vitamin, and mineral requirements we can use pure fat or oil (vegetable, animal, or a blend) to obtain the energy level the bird needs. Fat is akin to butter, margarine, and oil that we use to cook with. As nutritionists we use the term nutrient density to describe the energy and protein level of the feed.

Soybean meal, peas, canola meal provide protein. Protein is equal to nitrogen multiplied by 6.25% and is expressed as a percentage. Soybean meal for example is usually between 44-46% crude protein. Dietary protein is made up of 22 amino acids. We can fulfill some of the amino acid requirements using the pure forms of amino acids available which are lysine, methionine, threonine, and tryptophan but the rest have to be supplied by the major protein ingredients. These pure amino acids help us lower the total protein level in the ration which is healthier for the bird as they do not have to work to excrete the excess protein. Amino acids are ranked in terms of their ability to limit growth and reproduction, the first limiting are the sulfur containing amino acids methionine and cysteine and the second is lysine. Vitamin and mineral requirements which fulfill all the bird’s requirements for a healthy chicken are determined by the breeding companies for each breed of chicken. The CFIA also sets minimum and maximum levels for vitamins and minerals in order to ensure that no chickens are grown without adequate supplementation or conversely fed levels that could be toxic to them.

Generally, the growth period of the chicken is divided into four or five stages. The stages are broken down by age with a program such as 0 to 14 days, 15 to 21 days, 22-28 days, 29-35 days and 35 to 42 days. During these stages energy increases and protein levels decrease because as the chicken gets older feed intake increases and they are able to get more nutrients out of a lower density feed. A balanced diet, as is the case for humans also, contains levels of energy, protein (amino acids), vitamins, and minerals which produce a healthy, strong chicken.

As all humans are not the same size and shape neither are chickens. Therefore, it makes designing feeds that much more critical to make sure we supply all the nutrients the smaller bird needs because they eat less than their bigger brother. The goal in designing rations is to have a healthy, happy chicken.

Why are chickens bigger and why do they grow faster now than 50 years ago?

So you are on a family vacation across the border into the United States and you want to buy some chicken for dinner. You go into a grocery store and look for the chicken and notice it is seems bigger than our chicken in Canada and it is yellow. Why the difference? If you are from Ontario the color will be the same as you are used to because Ontario and the United States use corn based rations which result in a yellow pigment to the meat. Western Canada uses wheat based rations so the chicken has no color. The size difference is due to how old the birds are when they go to market. The older they are, the heavier they are. The United States markets at an average of 47 day with an average weight of 2.78 kgs, Canada has an average market age of 37 days and 2.33 kgs per bird.

Most flocks of chicken are grown ‘as-hatched’ which means a fairly even split of male and female birds. As in humans there is a size discrepancy between the two, with male chickens tending to be two days heavier than the females at the same age. Sometimes the flocks are sexed, which means males and females separated at the hatchery, and the farmer will get straight males or straight females. This is done most times to supply different retailers needs. Some retailers and restaurants sell whole birds and some chicken breasts, legs, and wings in separate packages. For example, there is the whole bird rotisserie market which requires birds of a certain weight range so that all the birds on the spit are very close to the same size. The same criteria is needed for the trays of breast meat marketed in stores, we don’t want to see one package with six big breasts and the next with 12 small ones. Or if you are selling a ‘bucket’ of chicken with 21 pieces the chicken provided has to be within a certain weight range so that 21 pieces fit in the bucket.

Genetics and technology have played a large role in speeding up the growth of our broiler chicken. The ingredients used to feed them are essentially the same as they were 50 years ago but our ability to determine what the bird’s nutritional needs and the best environment needed for them to be healthy has vastly improved. Canadian chicken does not contain added steroids or hormones. I do not know of any such products available for chickens and if there were such products they would require approval by the Canadian Food Inspection Agency for use in Canada. Genetic selection means selecting the birds that exhibit the trait we are looking for and mating the male and female together so that the desired trait has the best chance of being exhibited. For example, Canadian consumers want breast meat so as a result the breeding companies measure the breast meat on their birds, select the birds that have more breast meat, mate the male and female to have baby chicks, and keep doing this until the desired level of breast meat is obtained.

Fifty years ago chickens were fed by hand, had open water pails that were easily contaminated with litter or worse as the birds drank, and manually operated venting to have adequate air movement. Today barns are computerized to monitor feed and water supply, light intensity, static pressure, humidity level, temperature and a host of other environmental parameters to help ensure that the birds have the best environment possible for their health and welfare. Barns are set up to ensure that every chicken running around the barn has ample access to feed and water and the climate is controlled so that they are not chilled on cold winter days or subject to 100 degree heat. A healthy chicken requires ample space, good feed that provides all the nutrients required, protection from predators, ample light, plentiful clean water, and clean air. All these factors are necessary to grow good, healthy chicken.

Categories: Food

Antibiotic Use in Chicken Production

Chickens are vulnerable to two particular infections, necrotic enteritis which is caused by clostridia and coccidiosis which is caused by a protozoa (think of bugs so small they cannot be seen without a microscope). A chicken is always affected to some degree by these two organisms and if the infection is severe both diseases result in high mortality. We describe either infection with the term challenge, a high challenge level results in significant mortality while a low challenge may appear as lower than normal feed and water intake for a few days. The spike in water intake is a result of the birds trying to flush the bugs from their system. We do our best to lessen the challenge by providing an optimal environment such as ample space, clean and dry litter, uncontaminated and ample water, nutritionally balanced feed, and adequate light but the threat is always there. Our choice is between not giving our birds the best protection against the diseases that are available or doing nothing and knowing they will get sick. Coccidiosis can be controlled with a high but not 100% degree of certainty by vaccination of the chick at the hatchery or thru the use of coccidiostats in the feed which are not used in human medicine and whose sole function is to control the coccidial challenge. Necrotic enteritis is controlled thru the use of antibiotics which are highly effective if the challenge is mild to moderate or non-medicinal products which vary in their degree of effectiveness. Unfortunately the severity of the necrotic enteritis (NE) infection cannot be determined by any predictable factors. The fact is the birds will be challenged and even if they have the best environment and feed possible it is no guarantee that the challenge will only make them a little sick.

The Canadian chicken industry has voluntary stopped the preventative use of Category 1 antibiotics (those most important in human medicine). The levels are categorized as 1 to 4 with 1 being of very high importance and 4 being of low importance. The use of antibiotics in chicken feed is regulated by the Canadian Food Inspection Agency and requires prescriptions by licensed veterinarians. These regulations dictate which antibiotics can be used and at what level. The level allowed is set to ensure that the enteritis is controlled but not in excess so that the birds are over medicated which can lead to the development of resistant bacteria. The mentality of ‘if some is good, more is better’ does not apply here, the levels have been established using applied research. Antibiotics are not used to make up for poor management practices either they are used to help protect our chickens from getting sick or worse.

The number of alternative products to antibiotic use has grown rapidly in the past ten years. Products such as yeasts, protected organic acids, probiotics and prebiotics are being used in non-medicated flocks routinely. These products act to either crowd out the bad bugs or kill the bad bugs in the intestinal tract. As with any ingredient used in poultry feed they must also be approved for use by the Canadian Food Inspection Agency. The products go thru a stringent application process which requires them to prove their claim of bacterial control. While these products may not be as effective today as antibiotics for controlling enteritis their development is a priority. The ongoing research for alternatives to antibiotic use in poultry is a global poultry industry project as the industry tries to protect our chickens without traditional methods.

Categories: Food