1 Institute of Veterinary Anatomy, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, GermanyFind articles by
1 Institute of Veterinary Anatomy, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, GermanyFind articles by
2 College of Veterinary Medicine, School of Veterinary and Life Sciences, Murdoch University, Murdoch, AustraliaFind articles by
3 Institute of Poultry Diseases, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, GermanyFind articles by
1 Institute of Veterinary Anatomy, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, GermanyFind articles by
1 Institute of Veterinary Anatomy, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, GermanyFind articles by
In this study the macroscopic and microscopic structure of the heart of a fast growing, meat-type turkey line (British United turkeys BUT Big 6) and a wild-type turkey line (Canadian Wild turkey) were compared. At 8 and 16 weeks of age, 10 birds of each genotype and sex were sampled. The body mass and heart mass of the meat-type turkey both increased at a faster rate than those of the wild-type turkey. However in both turkey lines, the relative heart mass decreased slightly with age, the decrease was statistically significant only in the male turkeys. Furthermore meat-type turkeys had a significantly (p < 0.01) lower relative heart mass and relative thickness of the left ventricle compared to the wild-type turkeys of the same age. The wild-type turkeys showed no significant change in the size of cardiomyocytes (cross sectional area and diameter) from 8 weeks to 16 weeks. In contrast, the size of cardiomyocytes increased significantly (p < 0.001) with age in the meat-type turkeys. The number of capillaries in the left ventricular wall increased significantly (p < 0.001) in wild-type turkeys from 2351 per mm2 at the age of 8 weeks to 2843 per mm2 at 16 weeks. However, in the meat-type turkeys there were no significant changes, capillary numbers being 2989 per mm2 at age 8 weeks and 2915 per mm2 at age 16 weeks. Correspondingly the area occupied by capillaries in the myocardium increased in wild-type turkeys from 8.59% at the age of 8 weeks to 9.15% at 16 weeks, whereas in meat-type turkeys this area decreased from 10.4% at 8 weeks to 9.95% at 16 weeks. Our results indicate a mismatch in development between body mass and heart mass and a compromised cardiac capillary density and architecture in the meat-type turkeys in comparison to the wild-type turkeys.
The worldwide growing demand for poultry meat has resulted in pressure on breeders, nutritionists and growers to increase the growth rate of birds, feed efficiency, and size of breast muscle. Today, turkeys are marketed in about half the time and at about twice the body weight compared to 50 years ago [1]. These changes are due mainly to the high heritability of body weight and body meat composition [2]. This kind of selection has lowered the capacity of modern growing birds to respond to stressors, like the responses to heat stress in their environment [3] and some believe it has resulted in the failure of several organ and body systems because of the increased metabolic demands required for extremely rapid increases in body mass [4, 5].
Undesirable traits including many circulatory disorders, such as ascites, aortic rupture, spontaneous cardiomyopathy (round heart), and cardiomyopathy causing sudden death, each accompanied by a lowered muscle production and/or high mortality, in turkeys have arisen, presumably due to the stress induced by having such rapid growth [6–9]. As an example an enigma over recent times is the occurrence, often with no obvious causal agent, of perirenal hypertrophic cardiomyopathy in flocks of rapidly growing, heavy, male turkeys. Here mortality, usually 2–10%, is most common between 8–18 weeks, the period of most metabolic stress associated with rapid muscle development [5]. Julian [10] suggests that in turkeys with noninfectious cardiovascular disorders the cardiomyocytes can respond to significant changes in blood pressure and volume as well as to a lack of oxygen in only a very limited way, that is to enlarge to meet the increased demand placed on them.
According to Schmidt et al. [11] in a comparison of modern broiler turkey lines with heritage turkey lines, the apparent lower physiological capacity to accommodate increasing skeletal muscle volume of modern broilers can be explained partly by their low relative heart mass. They reported that the hearts of the heritage line birds [UIUC] grew at a rate of 7 mg/g of bird, whereas the hearts of the modern broiler birds [Ross] grew at a rate of 5 mg/g of bird. When heritage and modern broiler birds of equivalent weight were compared, the UIUC hearts were larger than those of the Ross lineage.
The postnatal growth of the heart in domestic birds has been studied predominantly from the standpoint of normal development [11] and pathology [7, 12]. Likewise the vascular system morphology of turkeys has been studied primarily from a gross pathology point of view [5, 13].
There is little information on the influence of age, gender and genetics on the development of the heart and the cardiac capillary architecture of turkeys. A comparative study was carried out to examine differences in heart structure over the critical growth periods of a highly selected meat-type and a wild-type turkey line, to elucidate the probable relations between genetic selection for rapid growth and cardiovascular diseases in turkeys. The aim was to compare morphological and microscopic architectural features of the heart and the myocardial capillaries of Canadian wild turkeys to that of a highly genetically selected meat-type domestic turkey line during their rapid growth period between 8 and 16 weeks of age.
For many of us, the Thanksgiving turkey is one of the highlights of the holiday feast. But have you ever wondered about the anatomy that keeps these birds alive and thriving? One of the most fascinating parts is the humble turkey heart. Though small in size, this muscular organ works tirelessly to circulate blood and oxygen throughout the turkey’s body. Let’s take a closer look at the size and anatomy of the turkey heart.
Average Size of a Turkey Heart
The turkey heart is a compact, efficient organ, allowing it to effectively pump blood through the cardiovascular system. On average, the healthy adult turkey heart is about the size of a walnut or golf ball, around 1 to 1.5 inches in diameter.
Of course, the exact size can vary somewhat depending on the overall size and age of the bird For example, the heart of a mature breeding tom turkey may be at the larger end of the range, while a younger hen’s heart is often smaller. But generally speaking, the turkey heart maintains a petite, efficient size whether from a 16-pound bird roasted for Thanksgiving or a hefty 30-pounder entered in a 4H competition
Positioning Within the Turkey’s Body
In addition to its small size, the strategic positioning of the turkey heart within the body plan aids its functioning. The heart is centrally placed within the thoracic cavity, nestled between the two lungs and surrounded by protective connective tissue membranes.
Having the lungs flanking the heart assists in re-oxygenating the blood supply as it circulates through the lungs. The membranes enclosing the heart also safeguard it from trauma or damage. Overall the turkey’s cardiovascular anatomy allows for smooth continuous blood flow.
External Features and Texture
When handling a raw turkey heart, you’ll immediately notice the smooth, muscular texture of the exterior. The tissue feels firm yet flexible to the touch. The heart is made up entirely of cardiac muscle unlike skeletal muscles used for locomotion.
In color, a healthy turkey heart typically appears a deep crimson red. This rich coloration comes from the high levels of iron and hemoglobin in the myocardium tissues that pump the blood. Any pale patches or odd textures on the surface may indicate disease or abnormalities.
Interior Chambers and Valves
Just like the human heart, the turkey heart contains four chambers and four valves to direct blood flow. The top chambers are the left and right atria, which receive blood from the veins. The bottom chambers are the stronger left and right ventricles that pump blood out to the arteries.
Between each chamber lies a valve – the mitral, tricuspid, pulmonic and aortic valves. These flexible gates swing open and closed to propel blood along its oxygenated route throughout the cardiovascular system. Though tiny by human standards, these valves and chambers are engineering marvels.
Vessels Bringing Blood to and from the Heart
A network of blood vessels transports blood to and from the four-chambered heart. Major arterial vessels include the aorta, pulmonary artery, brachiocephalic arteries, and coronary arteries.
The superior and inferior vena cava bring de-oxygenated blood from the body back to the heart, along with the pulmonary, coronary and hepatic portal veins. This complex circulatory routing delivers nutrients while removing waste for healthy body function.
Development and Changes Throughout the Turkey’s Life
A turkey poult hatches with a tiny, underdeveloped heart that grows rapidly to support the chick’s accelerated growth. Within just 8 weeks, commercial turkeys increase over 15 times in weight, requiring corresponding heart growth.
As the turkey matures, the heart’s contractions strengthen and cardiac output increases to supply the muscles, organs and tissues. By adulthood, the turkey heart beats an estimated 275 times per minute when at rest. With age, the walls may thicken and valves calcify, leading to a lower efficiency.
Caring For This Lively Organ
While we tend to focus on the tastiness of the breast meat, the living turkey requires an extremely functional heart to reach maturity. By feeding a balanced diet, controlling parasites, and promoting cardiovascular exercise, turkey producers can nurture healthy heart development.
So next Thanksgiving when you sit down to your turkey dinner, take a moment to appreciate the remarkable anatomy keeping that bird thriving during its life! The turkey heart may be small, but it delivers big benefits that are worth honoring.
Animals, Materials and Methods
This study involving turkey handling and treatments was carried out in accordance with German animal welfare law. The protocol was approved by State Office of Health and Social Affairs Berlin (LaGeSo Reg. Nr. 0218/07).
Forty wild-type turkeys (Wild Canadian Turkeys) (20 male and 20 female) obtained from a wildlife park (Wild- und Freizeitpark Ostrittrum, Germany), as well as forty meat-type turkeys from a highly selected line (British United Turkeys BUT Big 6) (20 male and 20 female) obtained from a commercial grow-out farm (Gut Jäglitz GMBH & Co. Agrar KG, Roddahn, Germany) were selected as day-old-chicks. This study was approved by the responsible Animal Care Committee (Landesamt für Gesundheit und Soziales Berlin, Germany).
Wild-type and meat-type birds were housed separately in two groups under the same husbandry conditions (10 birds/6.5 m2), in the Institute of Poultry Diseases, Department of Veterinary Medicine, Freie Universität Berlin. All birds were fed a commercial pellet diet (Ströh Hobbersdorf, Pansdorf, Germany) using a three stage feeding system. This consisted of starter feed (type 015) for weeks 1 to 6, then growers feed (type 016) from week 7 to 12, and finishers feed I (type 017) from week 13 onwards. All birds were allowed ad libitum access to food and water. The study ended on week 16.
Sample collection and processing
At 8 and 16 weeks of age, 10 birds of each genotype and sex were sampled. Live body masses were measured to an accuracy of 0.1 kg using a mechanical scale (Sartorius, Göttingen, Germany). Then the birds were killed according to Germany’s animal welfare standards by stunning and exsanguination. Immediately after a bird’s death the heart was dissected free from the carcass and weighed to an accuracy of 0.001 g on an electronic laboratory balance (Sauter-Cumulus, Freiburg, Germany). Then a one-centimeter-wide cross section sample was dissected from the midpoint between base and apex of the heart and prepared for morphometric examination ( ). Here the specimens were washed in 0.9% sodium chloride solution and fixed in phosphate buffered formalin (4%, pH 7, 24 h, room temperature). They were then dehydrated in a graded series of ethyl alcohol and embedded in paraffin wax. Serial sections were cut at 5 μm and stained either with hematoxylin and eosin (H&E) or with the capillary endothelial marker Arachis hypogaea lectin (Peanut agglutinin, PNA) according to Aescht et al. [14].
From each sample the thickness of both ventricular walls and the interventricular septum was measured in section stained with H&E using an analyzing system, Nis Elements (Nikon). Thicknesses of each ventricular structure were measured at three different locations at a magnification of 100x ( ). Structure thicknesses are defined as the average value of the 3 measurements.
In addition, from each bird, 25 cardiomyocytes from the left ventricular wall were measured at a magnification of 100x and the average value was calculated. Here the size of the cardiomyocytes was determined by measuring the cross sectional area and the diameter of the cardiomyocytes at the level of the nucleus.
To determine the density of the blood capillaries, for each bird, the area of interest was defined by randomly choosing 5 visual fields under 400 × magnification ( ). Only midmyocardial regions with transversely oriented myocytes and circular capillaries were used. The area of each field of view was 34124.89 μm2. The following parameters in lectin stained slides were then measured using an analyzing system NIS-Elements (Nikon):
- number of blood capillaries per mm2
- number of the cardiomyocytes per mm2
- intercapillary distance: 25 intercapillary distances for each sample were measured, starting with the capillary located nearest to the center of the field. The shortest distance from the outer circumference of this capillary wall was drawn manually to the neighboring capillaries and from these radially outwards until 25 distances were measured—and the average value was determined
- percentage of the area occupied by capillaries
Statistical analyses were performed using SPSS for Windows v. 20 software (SPSS, Chicago, IL). The mean values of the collected parameters were compared between the groups using the Mann—Whitney U-test, p < 0.05 was considered statistically significant. Results are presented as box-and-whisker plots (median, interquartile range, and range).
Wild Turkey Edible Organs with Steven Rinella MeatEater
Where are the vitals on a tom turkey?
If you draw an imaginary line between the points where the wingbones meet the body on both sides, this is the area of the vitals. On a tom turkey facing you, the heart and lungs are going to be aligned with a point just above the beard and just below the base of the neck.
What are the parts of a wild turkey?
There are many parts of a wild turkey that are amazing in appearance or function. Whether you are a hunter, bird watcher, or chef, you are probably interested in turkey anatomy. This brief overview covers the head, the organs, the legs, and wings of this wonderful creature. The turkey’s head is a facinating thing!
Do turkeys have a third eyelid?
Turkeys have a third eyelid known as a nictitating membrane. This nearly-translucent lid is used to clean and lubricate the eye. Essentially, the turkey does not have to blink with the upper and lower eyelids as we humans do, so they can keep their eyes open and on the lookout for danger. A very rough diagram of the turkey anatomy.
How do you store Turkey Heart & giblets?
Chop the heart into s mall pieces witha sharp knife, and season it with salt and pepper. Store the turkey heart and giblets in the refrigerator before cooking, and use within one to two days. Defrost the turkey heart and giblets in the refrigerator, cold water or a microwave oven. Find your way to better health.