Effect of Docosahexaenoic Acid in Dog Food on the Health and Intelligence of Dogs - Research Proposal Example

Effect of Docosahexaenoic Acid in Dog Food on the Health and Intelligence of Dogs INTRODUCTION Dogs have a long history of co-habitation with humans. They are considered as man's best friend and have become the most common pet animals throughout the world. In developed countries, more and more people are having dogs as their pets. Parallel to this is the rise in the quality of welfare afforded to dogs. People are finding ways how to improve the health and conditions of dogs and are spending time and resources for this objective. Research has long been involved in shedding light in to the health and diseases of dogs. Products are being developed to cater to the needs and problems of these animals. Dog foods are designed to give the proper nutrition and specific requirements of these pets. Recently, the importance of Docosahexaenoic acid (DHA) and fatty acids were highlighted by dog food makers. Fish oil, a rich source of fatty acids, was demonstrated in various uses such as improving dull coat of dogs, remedy for allergies, relieving inflammation, supporting brain and eye development. While there are specific studies that scientifically explain the functions of individual fatty acids, effects of doses of fatty acids, specifically DHA, in dog foods are not clear. DHA was proven to have beneficial effects on the brain development of young dogs and on the retina of growing and ageing dogs. There are claims of such benefits with the use of some dog foods but the methodology and results were poorly documented. This proposal aims to determine the effects, if there are any, and the extent of effects of DHA as a component of dog food on the health and intelligence of dogs. The objectives of this proposal includes 1) to determine the effects of different levels of DHA in commercial dog food (Hill's Science Plan) on learning and training ability of dogs, 2) to determine the effects of DHA in dog food through health indicators such as dog fur or coat and c) to determine the effects of DHA in dog food on eye functions of dogs. REVIEW OF LITERATURE Fatty Acids Fatty acids are forms of polyunsaturated fats. Examples of fatty acids are omega-3 and omega-6, classified based on molecular characteristics. Animals can synthesize on their own some fatty acids that they need. Those that they cannot produce but are instead obtained through external sources such as food are called essential fatty acids (Ackerman 1148). Omega-3 fatty acids include Alpha-linolenic acid (ALA) deficiency of which is related to skin disease development, Eicosapentaenoic acid (EPA) which is involved in vasoconstriction and related cardiac function and Docosahexaenoic acid (DHA) which is essential for brain and retinal functions. ALA is convertible into EPA and EPA is considered a major mover of the omega-3 fatty acids and is found in the cell membrane (Leaf 197-198, Kenny et.al. 660, Giron et.al.198). Omega-6 fatty acids on the other hand include Linoleic acid (LA) which is found in the skin, Gamma linolenic acid (GLA) and Dihomo-gamma-linolenic acid (DGLA) which are forms of LA, and Arachidonic acid (AA) which is involved in prostaglandin synsthesis. LA can be transformed into GLA. DGLA can be converted from GLA in the skin. LA is vital for optimizing skin's water permeability. AA in large amounts is detrimental to other fatty acids (Pitas 470, Campbell & Roudebush 82). DHA Docosahexaenoic acid (DHA) is a major constituent of brain phospholipids and serves an important function in sustaining structural and functional properties of membranes. DHA is coupled in glycerophospholipids generally with palmitic acid and stearic acid and with an additional long-chain polyunsaturated fatty acid which builds up in phosphatidylethanolamines. Adequate supply of DHA has been postulated to promote maximum neurological growth, information processing, the capacity to conduct electrical stimuli of nerve cells, and cognitive ability. There is consensus among experts that mammalian brain produces its own DHA during particular stages of intrauterine and postnatal development. After these stages, DHA remains in this composition unaltered (Alvarez et.al. 405,). Docosahexaenoic acid is the most important fatty acid of photoreceptor membranes that is essential for optimal retinal operation. Researchers found that docosapentaenoic acid is transformed to docosahexaenoic acid in the retinas of dogs (Reddy et.al. 68, Bazan et.al. 491, Bazan at.al. 591). Recent studies (Bauer 342, Hilton 106, Kelley et.al. 1, Anderson et.al.129, Ackerman et.al. 1158) explored the effects of DHA found in fish oils on health and overall behavior of dogs. One research showed accelerated learning of puppies when their mothers were supplemented doses of DHA. Fish oils were given during pregnancy of the mother and the early stages of the puppies' lives. After comparing with controls, identical puppies without additional DHA in their diet, they found out that puppies supplemented with DHA were able to learn faster and retain learned skills. DHA was also shown to prop up the retina or the component of the eye that collects light and transmits signals to the brain. Moreover, there are evidences that DHA has the capability of combating degeneration of the retina in older dogs. Together with arginine which is an amino acid, DHA was shown to extend dog remission and lifespan due to lymphosarcoma, a form of cancer, while undergoing treatment with an anti-cancer drug Sources of DHA Common food sources of DHA consist of fish such as salmon, tuna and other seafood, eggs, and meats such as poultry. Fish, fish products and fish oil may all contain DHA in dog foods. Puppies get their DHA from their mother before being born. After delivery, DHA is then passed on to the offspring through milk. Weaned puppies can then obtain DHA to facilitate brain and other organ development from food or prepared diet (Becker). Sources of DHA such as fish oil are not readily available for pet dogs. While dogs in the wild naturally obtain their DHA and other essential fatty acids through eating animal meat and bone and fish, domesticated dogs do not. They are limited to dog foods that obviously lack these essential fatty acids. Recently, dog food makers released formulae containing DHA to supplement the needs of dogs. Hill's Science Plan (Hillspet.com) is one of these dog food producers answering the need of domesticated dogs for DHA and other essential fatty acids. MATERIAL AND METHODS A. Effect of DHA in Commercial Dog Food on Intelligence of Dogs At least thirty (30) puppies from 15 bitches will be selected for feeding with dog food with three levels of DHA from pregnancy until adulthood of puppies. Dogs with almost the same characteristics, history and environmental condition will be chosen to reduce bias and experimental errors. Five treatments will be prepared which is one dog per treatment. Puppies that will be born for each mother will be included in the original treatment. Treatment 1 will include one pregnant dog which will be fed with low-DHA dog food. Treatment 2 will be fed with medium-DHA dog food. Treatment 3 will be fed with high-DHA dog food. Treatment 4 will be fed with dog food without DHA. Treatment 5 will be feed with dog food without DHA but will be added with raw fish oil. These dogs will be fed with the specified diets from the first month of pregnancy until birth of the puppies. Puppies will be evaluated for their skull size as a rough estimate of brain size. Alertness will be noted as a sign of mental activity. Relative speed of learning to crawl and walk will be recorded. Ten-month-old puppies will be subjected to simple intellectual tests to evaluate their early abilities to learn. Abilities to learn through identifying sounds and visual materials will be assessed for all the set-ups. The puppies will then be evaluated for learning abilities for simple commands such as sitting, standing and walking. One-year-old dogs will be evaluated for abilities to follow complex commands as fetching things and locating food. Tests will move on to more complex activities such as tackling mazes for rewards. Dogs will be scored based on the relative speed of recognizing, analyzing and following simple commands. Higher values will be allocated to solving complex problems such as mazes with additional points for shorter times. The following data setup replicated three times will be accomplished: TREATMENT AGE DEGREE OF COMPLEXITY OF COMMAND TIME OF ACCOMPLISHMENT TOTAL SCORE 1 Low-DHA 2 Med-DHA 3 High-DHA 4 None 5 Fish oil B. Effects of DHA in Dog Food on Overall Appearance and Health of Dogs Mother dogs will be observed for color, coat sheen and texture before, during pregnancy and after giving birth to the puppies. Scoring will be based on observations based on available standards on coat appearance for the same breed of dog, age and environmental conditions. Skin health will be assessed, with focus on presence of allergies, lesions and moisture. Puppies will be evaluated for coat texture and sheen immediately after birth, in the different stages of growth and in adulthood. The same parameters for the mother dogs will be used for the offspring. The following data set-up replicated three times will be accomplished: TREATMENT AGE DEGREE OF COAT LUSTER DEGREE OF COAT COLOR RICHNESS DEGREE OF COAT SMOOTHNESS TOTAL SCORE 1 Low-DHA 2 Med-DHA 3 High-DHA 4 None 5 Fish oil C. Effect of DHA in Dog Food on the Eyes of Dogs Regular checkups on the retina of mother dogs in different treatments will be performed to assess the effects of DHA in dog food. Development of retinal defects will be noted at the different stages of the dogs. Activities and functions related to eye clarity and efficiency will be evaluated and scored appropriately. These would include solving problems with the use of sight such as shape and action puzzles. Ability to recognize shapes and movements with time factor will be used in determining effects of level of DHA in food. Distance, shape complexity and speed will all be taken into account. The following data set-up replicated three times will be accomplished: TREATMENT AGE RETINAL QUALITY VISUAL TEST PERFORMANCE TOTAL SCORE 1 Low-DHA 2 Med-DHA 3 High-DHA 4 None 5 Fish oil Performance scores will be collated for every set of experiment. Statistical analysis will be performed for the significance of data results. The effect of DHA in dog food on health and intelligence of dogs will be determined based on the results. LITERATURE CITED Ackerman, L. "Nondermatologic Indications for Fatty Acid Supplementation in Dogs and Cats. Vet Med, 90(1995): 1158-1159. Ackerman, L. "Reviewing the Biochemical Properties of Fatty Acids. Vet Med, 90(1995): 1142-1144. Alvarez, R. A., Aguirre, G. D., Acland, G. M., & Anderson, R. E. "Docosapentaenoic Acid is Converted to Docosahexaenoic Acid in the Retinas of Normal and PRCD-affected Miniature Poodle Dogs." Investigative Ophthalmology & Visual Science, 35(1994): 402-408. Anderson, R. E., Maude, M. B., Acland, G., & Aguirre, G. D. "Plasma Lipid Changes in PRCD Affected and Normal Miniature Poodles Given oral Supplements of Flaxseed Oil. Indications for the Involvement of n-3 Fatty Acids in Inherited Retinal Degenerations. Exp Eye Res, 58(1994): 129-137. Bauer, J. E. "The Potential for Dietary Polyunsaturated Fatty Acids in Domestic Animals. Aust Vet J, 71 (1994): 342-345. Bazan, N. G., & Rodriguez de Turco, E. B. "Review: Pharmacological Manipulation of Docosahexaenoic-Phospholipid Biosynthesis in Photoreceptor Cells: Implications in Retinal Degeneration." J Ocul Pharmacol, 10 (1994): 591-604. Bazan, N. G., Birkle, D. L., & Reddy, T. S. "Docosahexaenoic Acid (22:6, n-3) is Metabolized to Lipoxygenase Reaction Products in the Retina." Biochem Biophys Res Commun, 125(1984): 741-747. Becker, J. "How the 'Smart Fish Oil' DHA Helps Your Puppy's Development." 8 April 2007 Campbell, K. L., & Roudebush, P. "Effects of Four Diets on Serum and Cutaneous Fatty Acids, Transepidermal Water Losses, Skin Surface Lipids,Hdration and Cndition of the Skin and Haircoat of Dogs. 11th Proceedings, Annual Members' Meeting, AAVD & ACVD Meeting (1995): 80-84. Giron, M. D., Mataix, F. J., & Suarez, M. D. "Long-term Effects of Dietary Monounsaturated and Polyunsaturated Fatty Acids on the Lipid Composition of Erythrocyte Membranes in Dogs." Comp Biochem Physiol , 102 (1992): 197-201. Hillspet.com. Hill's Science Plan. 8 April 2007 . Hilton, J. W. "Nutritional Requirements of Cats and Dogs." F. Zaworski (Editor). Feed Industry Red Book (1996): 106-123. Kelley RL, Lepine AJ, et al. "Effect of dietary fish oil on puppy trainability." In: Proceedings of the 6th Congress of the International Society for Study of Fatty Acids and Lipids (ISSFAL) Brighton, UK (2004). Kenny, D., Brooks, H. L., & Warltier, D. C. "Enhanced Alpha-adrenergic Vasoconstriction by n-3 Fatty Acids in Conscious Dogs." Am J Physiol, 258. (1990): 660-7. Leaf, A. "Omega-3 Fatty Acids and Prevention of Ventricular Fibrillation." Prostaglandins Leukot Essent Fatty Acids, 52 (1995): 197-198. Pitas, R. E., Nelson, G. J., Jaffe, R. M., & Mahley, R. W. "Effects of Diets High in Saturated Fat and Cholesterol on the Lipid Composition of Canine Platelets." Lipids, 14 (1979), 469-477. Reddy, T. S., Birkle, D. L., Armstrong, D., & Bazan, N. G. "Change in Content, Incorporation and Lipoxygenation of Docosahexaenoic Acid in Retina and Retinal Pigment Epithelium in Canine Ceroid Lipofuscinosis. Neurosci Lett, 59(1985): 67-72. Read More