User:ShannonDaley/sandbox

There are many concerns while feeding sporting dogs as there requirements are different from your everyday pet dog and there is very little research in specific nutritional requirements for different sporting events and the different breeds competing in them. Adequate energy is of a huge concern for feeding these dogs as they require a lot more energy than a regular pet dog. This is due to the nature of the activities the dogs are participating in such as endurance events (examples include sled dog racing, military and service dogs) as well as short term intense events (examples include sprint racing and fly ball). The amount of calories that is needed for each dog is on an individual basis determined from there activity level, this is very different from feeding your everyday average dog and if done wrong there are major consequences for the dogs such as injury and even death.

Protein

Protein is an essential component in any dog's diet. Muscle, hair, skin, ligaments, cartilage, and organs are structurally and functionally supported by protein. In comparison to the average pet dog, a performance or sporting dog requires a much greater protein intake to keep up with the physiological demands of high activity. These demands are a result of wear and tear on muscles and other organ tissues caused by strenuous activity. For sporting dogs, getting adequate protein is particularly important because it helps to reduce striated muscle tissue damage during exercise, which improves endurance and physical health.

Protein is also a vital component in bodily functions such as transporting oxygen and energy to the muscles, regulating blood glucose levels, fighting infections, and repairing tissues. Many diets targeted for performance dogs contain 30% protein, which supports prevention of training induced anemia. However, dogs performing in different athletic activities can require varying amounts of protein and essential amino acids. For example, studies have shown that optimal performance from sled dogs will require a high protein, high fat diet, where 30 to 40% of energy comes from protein and 50% of energy comes from fat compared to any other diet. Greyhounds which mostly compete in short but intense activities such as sprint racing were found to require a moderate protein (25% energy) and moderately high fat (30-50% energy) diet.

Diet recommendations are mainly attributed to the type of activity the dog is participating in. A sled dog would be performing mainly endurance exercise, in which the body utilizes aerobic metabolism, making fat the primary source of energy. This encourages a diet that is richer in longer-term fuel source fat than short-term fuel source carbohydrates. A study by found improvements in stamina and a decrease in frequency of physical injuries in sled dogs that was related to a low-carbohydrate diet, further supporting a high-fat diet. A greyhound, on the other hand, who participates in intense activity for a shorter period of time would be utilizing anaerobic metabolism, in which carbohydrates are used as the main energy source. This enourages a diet richer in carbohyrates than fat, the opposite of the recommendations for sled dogs.

Fat

Fat is an important component of the sporting dogs diet as it is a large contributor of energy. This is because when you are calculating the calorie content using the modified Atwater's equation, fat contributes on a factor of 8.5 x the amount of fat nutrient compared to protein and carbohydrates that are only multiplied by 3.5. This is because fat is a lot more calorie dense. It is the primary source of energy used by dogs during endurance exercises such as sled dog racing that uses mainly aerobic metabolism. The use of fat as fuel for aerobic pathways during exercise has been proven to be a more efficient use of energy than muscle glycogen as fuel for anaerobic pathways. In sport dogs, meeting energy requirements from high energy expenditure daily can be challenging for the owners, so efficiency in energy metabolism becomes an important factor to consider in diet formulation. The correct amount of dietary fat can increases the length of stamina in addition to energy production, while decreasing lactic acid production, and ultimately improving the aerobic performance of dogs.

Another important component fat provides to the diet is palatability. Palatability is very important for sport dogs because the dog must want to eat their food in order to benefit from the nutrients the food provides, and be capable of performing at a high athletic level. Fat is often used as an outer coating on extruded foods as a palatant which will make the food more tasteful for the dog.

Carbohydrates

Carbohydrates provide a quick energy source, increase palatability, and provide an important source of fibre . Though carbohydrates can be very beneficial for dogs performing high-intensive exercise for short periods of time, improvements in endurance performance have been related to a low-carbohydrate diet. This is due to differences in utilization of aerobic and anaerobic metabolism during different forms of exercise, diets that differ in carbohydrate inclusion will induce different nutrient availability in dogs performing different types of activities. For dogs that are performing activities which involve endurance it is recommended that carbohydrates make up no more than 22% of the diets total energy content. This is because in a recent study it was found that a diet containing more than 30-40% metabolizable energy of the diet as carbohydrates has been associated with ‘tying up’ (muscle abnormalities), coprophagy, and hypoglycemia during intense exercise. The same study by Loftus et al. found that decreasing carbohydrate content in the diet of sled dogs causes the muscle glycogen to increase over time during endurance activities, resulting in lower muscle glycogen depletion after an initial exertion of energy.

In an ingredient label, starch (a complex carbohydrate) may appear as rice, wheat, barley, corn and/or other varying grains. These ingredients not only supply the dog with quick and accessible energy during physical activitiy, but can also be used after exercise to replenish glycogen stores in organs such as the liver and muscle. Maize and sorghum as ingredients increased the production of propionate, which can be used for the process of gluconeogenesis, as well as butyrate. Glucose production is important specifically for performance dogs because they require high levels of energy for vigorous exercise, as their energy expenditure will increase drastically. Total carbohydrate levels are not displayed on feed labels due to the inaccuracy of current testing methods and varying methods in which certain sources may affect an animal's glycemic response. However, for canines, it has been demonstrated that rice has the greatest blood glucose response followed by wheat, barley, corn, and sorghum. It is recommended that diets containing rice or wheat should be blended with some low level carbohydrate sources such as sorghum or barley to prevent a dogs blood glucose levels from spiking.

Fibre

Highly soluble or fermentable fibre from carbohydrate sources such as beet pulp or barley also provide short chain fatty acids (SCFAs). These short chain fatty acids can represent approximately 10% of an animal's energy requirement through microbial fermentation within the gut. ^[11] Gastrointestinal tract health also promotes increasing mucosal health, which increases the microbial balance, improving digestion, and improving nutrient absorption which can also affect the up-regulating the immune system. ^[11] Prebiotic Fibres can also help to support the increase of production of SCFAs which can in turn lower the pH in the digestive tract and inhibits growth of potential pathogens. This process can promote the growth of beneficial bacteria such as lactobacilli.

SCFA can also improve immune function as it increases the number of T Helper cells, macrophages, and neutrophils. To insure this, it is recommended that all dog owners look for diets contain 3%-7% of total digestible fibre (TDF) or ingredients such as beet pulp or rice bran which are moderately fermentable. ^[12] Even though it is important for all dogs to have this is is especially important for dogs participating in high physical activities, as they need nutrients to be available to them and fermentable fibres can help to increase the time that the nutrients are available to be absorbed by slowing down the passage of food to waste. ^[12]

Total dietary fibre is not standard on pet food labels and generally only crude fibre is provided which makes it difficult to tell what the dog is really getting in terms of fibre as there is no indication of the solubility of fermentability of an ingredients. If non-soluble or non-fermentable fibre is found within the diet, the animal is likely to experience increased fecal bulk and moisture as well as a diluted energy intake. Consequently, dogs may experience decreased nutrient absorption, dehydration, pathogenic bacterial growth in the gut and diarrhea. Avoiding diets with crude fibre levels over 3% or high inclusions of ingredients such as cellulose or peanut hulls will assist in preventing some consequences such as pathogenic bacterial growth, colonic atrophy and dehydration. ^[12] Furthermore, there are some additional fibres such as fructooligosaccharides (FOS) and mannanoligosaccharides (MOS) which can help promote good bacteria and avoid harmful ones, respectively. ^[12] These two fibres are important for animals sporting animals who receive raw food as part of there diet where pathogenic bacteria may be more prevalent. The practices of feeding raw food to sports animals to increase protein and fat consumption is quite common so these fibres need to be included with ingredients and many times as supplements with the diet. ^[12]

The addition of oligosaccharides (MOS and FOS) can be advantageous as they can alter the colonic microbiota in favour of the beneficial bacteria present in the gut of the canine. They are also able to increase the level Volatile fatty acids in the gastrointestinal tract which can be used for energy by the dog during activity as well when they are recovering from an event, to help maintain healthy gastrointestinal tissues. The addition of FOS and MOS currently in the dry dog food industry has not been shown to be very effective, but may be beneficial if supplemented at a higher level to these sporting dogs.

Water

Sporting dogs participate in many different events that all cause different types of stress and exertion on there bodies. A main part of the up keeping in there metabolic process is the addition of water. This is due to the fact that bodily water contents are constantly changing based on the intake and excretion of water via urination, drinking, panting, and a minimal amount of perspiration that dogs have. Other factors that can influence a sporting dogs water state is ambient temperatures, sodium intake, and availability to clean and good tasting water. This means it is extremely important for dogs with increase activities levels to have increased water consumption and availability. Many owners 'bait' water which is the process of adding in palatinates and flavours to the water to try and increase water consumption. This is a common practice done with sled dogs.

For sled dogs in particular the performance of the dogs will not be optimal if they do not receive enough water as they preform over long distances and it can be over multiple days. An indecent amount of water for sled dogs can have dangerous consequences on the dog such as dehydration and can also increase the risk of hyperthermia.

Additives

Some additives that are important in sporting dog diets include glucosamine, chondroitin sulphate, calcium and omega-3 fatty acids, such as Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) from fish oil.

The ratio of Omega-6:Omega-3 fatty acids is considered important for all dogs but has been shown to increase sport dog performance if it is found to be between 5:1 and 10:1. This ratio will ensure an adequate balance of the pro-inflammatory and anti-inflammatory responses of the dog. Promoting optimal injury prevention as well as increasing skin and coat health. Omega fatty acids have been shown to help decrease the development of chronic swelling and decrease existing inflammation caused by arthritis (a common disease sports dogs are more likely to suffer from due to increase use of joints). The omega fatty acid ratio is also an essential component of cartilage regeneration (repairing injuries) and metabolism (nutrient absorption). Therefore, this component of the diet is a large contributor for regulating the imbalance of catabolic and anabolic processes in Osteoarthritis and also to reduce cartilage degeneration due to inflammation.

Clinical studies show that oxidative stress is increased when exercise is increased due to accumulation of free radicals which have been linked to support cancer and other diseases that would affect the optimal performance and life span of the dog. L-carnitine (L-3-hydroxytrimethylaminobutanoate) is a naturally occurring compound which is used in the oxidation of mitochondrial long-chain fatty acids. L-carnitine is synthesised in the hepatic and renal systems of dogs, yet this is not the case within cardiac muscle or skeletal muscle. Studies have shown that L-carnitine improves the lean mass of dogs, when supplemented appropriately. Increases in lean mass can help prevent increases in fat deposition. Specifically for the performance dog, L-Carnitine helps prevent the loss of proteins from muscle inflammation, as well as oxidative stress during strenuous exercise. As performance dogs are often vigorously exercising for long periods of time, it is important to have more lean muscle mass and less fat to improve performance and benefit their overall health

Glucosamine and chondroitin sulfate are chondroprotectives that can modulate osteoarthritis. They are an essential component of cartilage regeneration and metabolism. This helps with regulating the imbalance of catabolic (break down) and anabolic (building) processes in osteoarthritis. These components also reduce cartilage degradation in the joints as a result of inflammation. It is essential for performing dogs to have healthy joints that do not cause any discomfort or pain. Supplying chondroitin sulfate and glucosamine will help prevent pain and discomfort in the joints of a sport dog.

An important factor for both endurance and short term events is proper calcium supplementation, meat is not balanced with all of the necessary minerals especially for athlete dogs who are much tougher on there bones and joints. A deficiency in Calcium can result in hyperparathyroidism, poor bone mineralization and increased risk of fractures in dogs. Calcium deficiency can supplemented carefully by adding 1 g of bone meal to each 50 g of meat, this must be regulated carefully as excess supplementation can increase the risk of osteochondritis in growing large breed dogs.

Diet considerations based on competitive events

There are many factors to be considered when formulating or purchasing a diet for a sporting dog. Some of these factors can include breed, age, genetics, and the sport, events or work the dog will be participating in. It is important to select a diet that provides the necessary nutrients and energy to optimize athletic performance by contributing to the dogs overall health as well as choosing ingredients that will increase palatability so energy consumed can be maximized. Studies have shown that energy requirements are distance-dependent, meaning they are proportional to the distance travelled by the animal, not the speed of travel. Therefore, endurance events such as sled dog racing will have higher energy requirements than short-distance sprinting events.

Endurance events are classified as prolonged exercise at sub maximal levels of exertion. These events can include dog sled racing, hunting and herding and longterm military or police situations. To sustain this high level of activity for long periods of time, energy is provided to the muscles mostly through aerobic metabolism (even though anaerobic is still occurring in certain situations) where high energy fat is utilized as the main fuel source. An Increased portion of protein is beneficial to support gluconeogenesis from amino acids during endurance events and to aid recovery. Therefore, several studies have shown an increase in stamina when sporting dogs are fed a high protein (>30 or 40% of energy), high fat (>50% of energy) diet. Carbohydrates on the other hand are required in lesser amounts for this type of exercising dog. In endurance activity dogs it has bee found that dogs fed a high carbohydrate diet showed signs of tying up and hypoglycaemia during endurance exercise.

Sprinting events are characterized by short bursts of speed and agility that rely mostly on anaerobic metabolism to provide energy to the muscles.  Greyhounds are a common breed to use for this type of study because they are uniquely adapted for sprinting. Carbohydrates are the main source of fuel for these short initial accelerations. Glycogen levels are depleted in the first several seconds of sprinting before the muscles switch to aerobic metabolism that favours fat sources in dogs doing longer activity.  Even though a little more controversial than sled dogs it is suggested that reaching greyhounds be fed a moderately high fat (30–50% of energy), moderate protein (24% of energy).

Sled dogs

The nutrition requirements for sporting dogs is limited at the time but generally focus on sled dogs. This is an extreme endurance event in which nutrition is critical for and reveal results readily. Sled dog racing is an intense sport that can last from 2 to 3 days or sometimes even longer, over very long distances. In these harsh conditions the dogs need a great amount of calories for endurance to be able to continue to compete without being injured. This means that their diet is even more specific to what they will be using the nutrients for. Many sled dog racers have different opinions on how to feed their dogs and this varies from raw food to regular dog kibble.

Research in this particular field is a good judge on the rest of the sporting and performance dog industry as it is an extreme scenario. Researchers tend to use the Doubly labelled water method but vary quite a lot in results. Some have ranged from16 700 kJ/d to 47 100 kJ/d in another for sled dogs during an event (very large difference in calories per day). There are many different factors that scientists have claimed that can make a difference, a few of those factors include; ambient temperatures, terrain, distance travelled, speed, activity, age, and genetics. The data collected must be taken with consideration that it is hard to collect this data as there are a number of variables. The results must be interpreted cautiously since the present study relied strictly on musher interview and questionnaires. This shows that this field is in much need of continued research to improve the health and performance of these dogs.