Nutritional Analysis of Animal Food Stuff - Report Example

Nutritional Analysis of Animal Food Stuff Introduction Food may be of plant or animal origin that is ingested in the body as a source of nourishment to sustain life. This contain the required nutrients such as carbohydrates, fat, proteins, vitamins and minerals to maintain life and growth (Farlex, Inc, 2008) Dogs are one of the creatures that need the right food in order to sustain their growth, activity and live healthy. Depending on the needed calorie intake which is based on the level of activity, breed, age and state of the dog, a balanced diet is required. It should contain the right amounts of nutrients such as carbohydrates, fat, protein, vitamins, minerals and water. Dogs require a lot of proteins as source of amino acids especially those that are not synthesized by the body but needed for tissue building and repair. Some benefits of protein in the dog’s diet include: building of hormones for growth and metabolism, building of antibodies to fight infection and enzymes that aids in the digestion of food. Fats are mainly for energy/calorie source of dogs but more so, it is important because it contains some of the most important vitamins and minerals essential for the dog’s health and well-being. It is also gives palatability and texture to the food. Most important fat is linoleic acid which improves luster and quality to the dog’s skin and coat. Carbohydrates are also a source of energy but dietary fibers are needed for proper digestion and health. On the other hand, dogs also require vitamins and minerals for good metabolic processes, growth of cells and stabilization of body fluids. Lastly, water by far is the most important requirement in a dog’s diet as it’s essential in almost every bodily function such as transportation of body fluids and nutrients, a solvent and helps regulate body temperature (Kremers, B. 2007 and UK National GSD Helpline, 2008). A variety of dog food is available in the market which differs depending on the source and nature as well as in the nutritional content to meet the dog’s requirement, Dog food can be dry, semi-moist or canned type but other choices such as raw, home-cooked, organic, vegetarian and “all-natural” are gaining quick popularity (Walsh, 2008). Of the conventional types of dog food, dry has more advantages than semi-moist and canned wet food. Dry food is convenient to serve, has less odor, stores easily and longer, prevents tartar, exercises the mouth and is less expensive than semi-moist and canned wet food (Drs. Foster and Smith Educational Staff, 2008). Determination of Nutritional Values Nutritional values in food are determined for a number of reasons such as compliance to standards, nutrition labeling and characterization of raw materials. Laboratory analyses of food nutrients are very useful in determining the right food to consume. In dogs, having the right food with the right amount of nutrients is vital. Analyses are usually done to determine the basic nutrients such as carbohydrates, proteins, fats and moisture. a. Crude Protein Proteins are polymers of amino acids and are characterized as being the only food macronutrient with nitrogen. Several methods are available for estimation of protein content and the simplest and common methods is the Kjeldahl Method. The method involves the estimation of total nitrogen content followed by the conversion of the percentage of nitrogen to protein by multiplying it with a factor based on the percentage of nitrogen in the food protein. The procedure follows three general steps (Dumelod, 2004) 1. Digestion with concentrated H2SO4 (oxidizing agent) and catalyst: Cu, Ti, Se, Hg heat Sample + H2SO4 → CO2 + H2O + SO2 + (NH4)2SO4 + other ions Catalyst 2. Distillation of NH3 (by sodium hydroxide – to raise BP of mixture; heating with steam) 1. (NH4)2SO4 + 2NaOH → 2NH3 + H2O + 2 Na+ + SO4- 2. NH3 + H3BO3 ↔ NH4+ + H2BO3-  3. Titration with Acid H2BO3- + H3O+ ↔ H3BO3 + H2O a. Ether Extract Ether extract is the also known as determination of fat content of a food sample and is based on differential solubility of food components due to the fact that fats or lipids are soluble in organic solvent which makes it easy to separate from water soluble components of foods, i.e., proteins, carbohydrates and minerals. The method can be on a batch or continuous extraction method. The continuous extraction method allows the extracting solvent such as petroleum ether or ethyl ether from a boiling flask to continuously flow over a known weight of the dried food sample in a porous thimble. The solvent extracts the fat from the sample as it passes through it and the process repeated for about 1 hour until all fat is extracted from the sample. The fat is desolventized and weight loss of the sample or weight of fat in the flask is the fat content (James, 1995). b. Crude Fiber Crude fibers are carbohydrates that are unavailable for consumption or are plant polysaccharides that are indigestible. Many crude fiber methods have been developed based on the process that occurs in the digestive system. The most common of method of determining crude fiber in foods is Weende Method which determines cellulose, some hemicelluloses and lignin but not pectins. It involves sequential hydrolysis with dilute acid (1.25% H2SO4), then with dilute alkali (1.25% NaOH), boiling in distilled water, collection of insoluble residue by filtration, drying, weighing and ignition to constant weight. Ashing or ignition removes the mineral contaminants of the fiber residue. The sample collected is the dietary fiber of the food sample (McClements, 2004). c. Neutral Detergent Fiber This is another method of determining crude fiber in food which prevents the use of highly corrosive acids and therefore lessens danger. The Neutral Detergent Fiber method uses sodium dodecyl sulphate or sodium lauryl sulphate to estimate insoluble fibers. The insoluble dietary fiber is estimated by first extracting the lipids from foods containing more than 10% fat by the use of petroleum ether and left to air dry. The sample is then refluxed for 1 hour with buffered sodium lauryl/ dodecyl sulphate detergent or a neutral detergent solution. Amylase solution is then added to remove the starch. Sample is then incubated overnight with few drops of toluene and washed with small amounts of water and acetone. The residue is then dried, cooled and weighed. This represents the insoluble dietary fiber which is composed of cellulose, hemicellulose and lignin (Nielsen, 1998). d. Energy Value by Near Infrared Reflectance Spectroscopy (NIRS) Near Infrared Reflectance Spectroscopy is based on the principle of measuring the intensity of reflected infrared waves emitted from the surface of the sample due to the absorption of wavelengths or frequencies at the near infrared region (700-2500 nm or λ= 0.8 -2.5 μm) caused by the vibrations or rotations of certain molecular groups in the food sample (McClements, 2004; Nielsen, 1998). A greater reflectance is obtained when a lower absorbance occurs in the sample. These are usually done in analyzing the carbohydrates or proteins in the sample to determine the energy value. Normally, food is analyzed using a NiRSystems instrument and samples are placed in rectangular cups and then scanned at given intervals. The reflectance data, commonly expressed as log 1/R is measured by the NIRS instrument as data points. These data points are then analyzed using multivariate regression analysis against standard samples. Food samples should be solid or granular in order to absorb and reflect the radiation present (Nielsen, 1998). Energy requirements of a dog Dogs require different energy requirements depending on the size, stage of growth, physiological state and activity level. Table 1 shows a guide in determining the daily energy requirements of dogs at based on its RER or Resting Energy Requirements where RER in kcal/day = 30 (body weight in Kg) + 70 (Foster and Smith, Inc. 2008). Additional activity will require extra RER thus increase in needed caloric intake. Villanueva (2002) also provides an estimated calculation of Metabolic Energy Requirements (MER) of dogs at varying growth stage, activity and physiological state. Meeting the required daily energy requirements should also be in conjunction with a balanced nutritional diet. Improper nutrition in a dog’s diet poses several problems and risk. While carbohydrates are essential to a dog’s diet, overfeeding will result to obesity, indigestion due to lactose intolerance and digestive upsets due to insufficient or too much fiber (Foster and Smith, Inc. 2008). Lack or excess of essential amino acids and the required amount of protein contributes to weight loss, a dull coating, stunted growth and poor health in terms of heart and kidney problems. Vitamin toxicity in dogs is very low unless it is fed with concentrated supplements. On the other hand, excess minerals such as calcium and phosphorus obstruct manganese absorption, iron with zinc absorption and magnesium with calcium absorption (Kremers, 2007). Table 1. Dog activity levels and daily energy requirements. Activity Daily Energy Requirements Weight Loss 1.0 x RER Puppy-weaning to 4 months 3.0 x RER Puppy -4 months to adult 2.0 x RER Neutered adult normal activity 1.6 x RER Intact adult normal activity 1.8 x RER Light work 2.0 x RER Moderate work 3.0 x RER Heavy work 4-8 x RER Pregnant dog (first 42 days) 1.8 x RER Pregnant dog (last 21 days) 3.0 x RER Lactating female 4-8 x RER A standard adult German Shepherd female dog weighing 30 Kg as family pet requires about 1692 kcal/day. This is calculated based on the maintenance energy requirements (MER) or the amount of energy expended by a moderately active adult dog enough to sustain body weight. It is calculated using the formula in the UC Davis School of Veterinary Medicine 1995 publication, MER = 132 x (body weight in kilograms)0.75 where 132 is the kcal needed per kg body weight. However, the Waltham Calculator which uses Burger’s MER method, yields an estimated daily energy requirement of only 1410 kcal/day (Villanueva, 2002). German Shepherds are considered in the category of the large breed dogs (Royal Canin, 2006) and can live on a balanced diet. They have a short colon thus a high fiber diet is needed for better absorption of nutrients. Dry foods are best to keep cavities at bay. It is best to make fresh food from quality ingredients in feeding an adult German Shepherd female pet dog. A German Shepherd’s diet should consist of 18-22% or more protein, 9-15% fat (Foster and Smith, Inc. 2008) and not more than 70% carbohydrates (Dogland, 2008). However, other nutrients should be taken into consideration such as vitamins, minerals and especially water. Table 2 shows the estimated quantity of nutrients per Kg body weight needed by an adult German Shepherd Dog approximately 30 kg. Table 2. Nutrient quantity for an adult 30 kg German Shepherd Dog. Nutrient Estimated Quantity per Kg body weight Protein (18-22%) 3 g/kg Fat (9-15%) 1g/kg Carbohydrates (30-70%) 11 g/kg Water (2.5x daily food intake) 37.5 ml/kg Proteins are the building blocks of the body which contains amino acids needed for the growth and repair of tissues. German Shepherds can obtain their protein from fresh brown lean meat such as ground beef, lamb, chicken and turkey. Fats are the main source of energy for most dogs and this can be obtained from vegetable oils such as olive oil, soybean oil, corn oil and some fish oils. It is however essential to provide dogs with linoleic acid in combination with zinc to keep dog skin and coat healthy as shown by studies of WALTHAM (UK National GSD Helpline, 2008 and Ryan, 2008) Carbohydrates are also excellent source of energy and fiber which is very important in the digestive health of German Shepherds. This can be met by feeding the dog with sugar beet pulp, oatmeal, breadcrumbs, mashed potato, wheat germ and many more. About 60% of an adult dog consists of water which makes it the most important nutrient of all. Fresh water of highest quality should always be provided at all times to a pet family GSD for them to function properly and live healthy lives. Based on these facts, an adult German Shepherd should be given a balanced healthy diet of fresh food containing the essential nutrients. A recommended home made diet should consist of: 425 g cooked meat from chicken, turkey, beef or lamb, 225 g boiled rice, 4 oz yogurt, 10 ml combined vegetable oil and fish oil, 20 grams oats or wheat germ, 56 grams of green leafy vegetables such as spinach, parsley or any herbs, 1.5 oz of molasses or honey, 100 g liver or any viscera and some vitamins and mineral supplements. Some ingredients such as potatoes, carrots and onions, can be substituted to grains give variety to the dog’s diet and can be prepared ahead of time in batches then frozen or made fresh daily. Therrien (2007) have also a formulated a home made dog food with a balanced nutrition which makes her German Shepherd healthy. This diet is only an estimate of meeting the required nutrients of a GSD and is entirely different to a complete manufactured dog food as the latter contains all the necessary nutrients as prescribed by the manufacturers. Royal Canin (2006) recommended about 4 cups or 328 g per day of their German Shepherd 24 dog food for a 30 kg GSD. These dog foods have been studied to give the best nutrition to dogs. On the hand, foods that are not guarantee to contain all that the animal need is called complementary food and the dog should be given additional food to have a complete and balanced nutrition. Giving a dog all meat rations would cause thinning of bones and causes fractures (Provet, 1999). Buying a manufactured complete dog food has its advantages and disadvantages over a home made diet dog food. Complete dog foods are easier to prepare and store while a home made diet dog food while take time and requires a lot of attention. Although it is easier to just buy a complete dog food and feed to a dog especially dry dog food, it is also best to combine this and balance with home made prepared food to give variety to the diet to dogs. Conclusion Food is essential in every living creature and all requires the right amount of nutrients in their daily diet for healthy sustenance and functioning of the body including dogs. Dogs need the right amount of carbohydrates, fat, protein, vitamins and minerals and water in their diet. Laboratory analyses of foodstuff allows for the estimation of the nutritional value of a food substance. Several techniques are utilized such as simple drying to determine the moisture or water content to instrumental analysis such as spectroscopy to determine energy value. Proteins measured by the estimation of the total nitrogen present, fat by ether extraction process and crude fiber by obtaining carbohydrates that are not hydrolysable with acids and alkali or the use of neutral detergents. Energy value on the other hand can be determined through NIRS method. The proper diet and food that a dog needs to take into consideration the required nutrients it needs. Different dogs have different nutritional requirements of proteins, fats, carbohydrates, vitamins and minerals and water depending on its size, stage of growth and physiological state. Making a home made diet that would meet the entire dog’s nutritional requirement is difficult thus it would also be wise to supplement with manufactured pet food as these are fortified with the necessary vitamins and minerals that may be lacking in a home made diet. Although it is more cost effective to buy complete dog food looking at the advantages it poses, as compared to making a home based diet. References Cusick, W. D. 2008. What to feed a German Shepherd Dog. Online. Available from: http://home.att.net/~wdcusick/GermanShepherdDog.html [5 May 2008] Dogland.co.uk. 2008. Nutrition for Puppies, Adults and Seniors. Online. Available from: http://www.dogland.co.uk/NutritionForPuppiesAdultsAndSeniors.html [5 May 2008] Drs. Foster and Smith Educational Staff. 2008. Dog Food Types FAQs. Online Available from: http://www.drsfostersmith.com/pic/article.cfm?aid=376 [8 May 2008] Dumelod, B. D. 2004 Proximate Analysis Handout. Food Science and Nutrition Department, U.P. College of Home Economics. Farlex, Inc. 2008. The Free Dictionary. Online Available from: http://www.thefreedictionary.com/food [8 May 2008] Foster and Smith, Inc. 2008. Pet Education: Dogs. Online Available from: http://www.peteducation.com/index.cfm?cls=2 [8 May 2008] James, C. S. 1995. Analytical Chemistry of Food. Glasgow: Blackie Academic and Professional Kremers, B. 2007. Best Dog Food Guide. Online Available from: http://www.best-dog-food-guide.com/feeding-amount-for-dogs.html [5 May 2008] McClements, D. J. 2004. Analysis of Food Products. Online. University of Massachusetts. Available from: http://people.umass.edu/mcclemen/581Toppage.html [15 June 2004] Nielsen, S. S. 1998. Food Analysis 2nd Ed. Gaithersburg, Maryland: Aspen Publishers, Inc. Provet. 1999. Keeping Pets Healthy Through Nutrition. Online. Available from: http://www.provet.co.uk/petfacts/healthtips/petfeeding.htm [8 May 2008] Royal Canin. 2006. Dog Size Health Nutrition. Online. Available from: http://www.royalcanin.co.uk/retailers/dog_size_health_nutrition.aspx [8 May 2008] Ryan, J. 2008. What to Feed Your German Shepherd. Online. Available from: http://www.articleslide.com/articledetail.php?artid=45183&catid=372&title=What-To-Feed-Your-German-Shepherd [5 May 2008] Therrien, R. 2007. Diet. German Shepherds. Online Available from: http://en.allexperts.com/q/German-Shepherds-2354/diet-1.htm [5 May 2008] UK National German Shepherd Dog Helpline. 2008. A Balanced Diet. Online Available from: http://www.gsdhelpline.com/feeding.htm [5 May 2008] Villanueva, M. 2002. Metabolic Energy Requirements for Dogs. Online. Available from: http://www.mycockerspaniel.com/mer.htm [5 May 2008] Walsh, H. 2008. Types of Dog Food. Online Available from: http://www.petcaretakers.com/dog-nutrition/dog-food.php [8 May 2008] Read More

Digestion with concentrated H2SO4 (oxidizing agent) and catalyst: Cu, Ti, Se, Hg heat Sample + H2SO4 → CO2 + H2O + SO2 + (NH4)2SO4 + other ions Catalyst 2. Distillation of NH3 (by sodium hydroxide – to raise BP of mixture; heating with steam) 1. (NH4)2SO4 + 2NaOH → 2NH3 + H2O + 2 Na+ + SO4- 2. NH3 + H3BO3 ↔ NH4+ + H2BO3-  3. Titration with Acid H2BO3- + H3O+ ↔ H3BO3 + H2O a. Ether Extract Ether extract is the also known as determination of fat content of a food sample and is based on differential solubility of food components due to the fact that fats or lipids are soluble in organic solvent which makes it easy to separate from water soluble components of foods, i.e., proteins, carbohydrates and minerals.

The method can be on a batch or continuous extraction method. The continuous extraction method allows the extracting solvent such as petroleum ether or ethyl ether from a boiling flask to continuously flow over a known weight of the dried food sample in a porous thimble. The solvent extracts the fat from the sample as it passes through it and the process repeated for about 1 hour until all fat is extracted from the sample. The fat is desolventized and weight loss of the sample or weight of fat in the flask is the fat content (James, 1995). b. Crude Fiber Crude fibers are carbohydrates that are unavailable for consumption or are plant polysaccharides that are indigestible.

Many crude fiber methods have been developed based on the process that occurs in the digestive system. The most common of method of determining crude fiber in foods is Weende Method which determines cellulose, some hemicelluloses and lignin but not pectins. It involves sequential hydrolysis with dilute acid (1.25% H2SO4), then with dilute alkali (1.25% NaOH), boiling in distilled water, collection of insoluble residue by filtration, drying, weighing and ignition to constant weight. Ashing or ignition removes the mineral contaminants of the fiber residue.

The sample collected is the dietary fiber of the food sample (McClements, 2004). c. Neutral Detergent Fiber This is another method of determining crude fiber in food which prevents the use of highly corrosive acids and therefore lessens danger. The Neutral Detergent Fiber method uses sodium dodecyl sulphate or sodium lauryl sulphate to estimate insoluble fibers. The insoluble dietary fiber is estimated by first extracting the lipids from foods containing more than 10% fat by the use of petroleum ether and left to air dry.

The sample is then refluxed for 1 hour with buffered sodium lauryl/ dodecyl sulphate detergent or a neutral detergent solution. Amylase solution is then added to remove the starch. Sample is then incubated overnight with few drops of toluene and washed with small amounts of water and acetone. The residue is then dried, cooled and weighed. This represents the insoluble dietary fiber which is composed of cellulose, hemicellulose and lignin (Nielsen, 1998). d. Energy Value by Near Infrared Reflectance Spectroscopy (NIRS) Near Infrared Reflectance Spectroscopy is based on the principle of measuring the intensity of reflected infrared waves emitted from the surface of the sample due to the absorption of wavelengths or frequencies at the near infrared region (700-2500 nm or λ= 0.8 -2.5 μm) caused by the vibrations or rotations of certain molecular groups in the food sample (McClements, 2004; Nielsen, 1998).

A greater reflectance is obtained when a lower absorbance occurs in the sample. These are usually done in analyzing the carbohydrates or proteins in the sample to determine the energy value. Normally, food is analyzed using a NiRSystems instrument and samples are placed in rectangular cups and then scanned at given intervals. The reflectance data, commonly expressed as log 1/R is measured by the NIRS instrument as data points. These data points are then analyzed using multivariate regression analysis against standard samples.

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