Changes

==Toxicity==

==Toxicity==

Excess energy intake is not toxic, though long-term excess intake can result in obesity and its associated health risks. Obesity is associated with an increased risk of [[Diabetes Mellitus|diabetes mellitus]] in cats<ref>Lutz TA and Rand JS. A review of the new developments in type 2 diabetes mellitus in human beings and cats. Brit Vet J 1993;149:527-536.</ref>, in growing puppies can result in development skeletal abnormalities<ref>Hedhammer A, et al. Overnutrition and skeletal disease. Cornell Vet 1974;64(suppl 5):9-150.</ref><ref>Kealy RD, et al. Effects of limited food consumption on the incidence of hip dysplasia in growing dogs.  JAVMA 1992;201:857-863.</ref>, and can worsen clinical sign of orthopaedic disease and decrease longevity in adult dogs<ref>Kealy RD, et al. Effects of diet restriction on life span and age-related changes in dogs.  JAVMA 2002;220:1315-1320.</ref>.

Excess energy intake is not toxic, though long-term excess intake can result in obesity and its associated health risks. Obesity is associated with an increased risk of [[Diabetes Mellitus|diabetes mellitus]] in cats<ref>Lutz TA and Rand JS. A review of the new developments in type 2 diabetes mellitus in human beings and cats. Brit Vet J 1993;149:527-536.</ref>, in growing puppies can result in development skeletal abnormalities<ref>Hedhammer A, et al. Overnutrition and skeletal disease. Cornell Vet 1974;64(suppl 5):9-150.</ref><ref>Kealy RD, et al. Effects of limited food consumption on the incidence of hip dysplasia in growing dogs.  JAVMA 1992;201:857-863.</ref>, and can worsen clinical sign of [[:Category:Musculoskeletal System - Pathology|orthopaedic disease]] and decrease longevity in adult dogs<ref>Kealy RD, et al. Effects of diet restriction on life span and age-related changes in dogs.  JAVMA 2002;220:1315-1320.</ref>.

==Dietary Sources==

==Dietary Sources==

'''Foods differ in the amount of energy, and this is a primarily a function of the amount of moisture, digestibility, and the amount and proportions of macronutrients'''. Digestibility (i.e., feeding) studies are the most accurate way of determining the ‘available’ energy content of a food, but these studies are expensive and require the use of laboratory animals. Many pet food companies do not have the resources to conduct digestibility studies and use predictive equations instead. There are different predictive equations for pet foods and human foods, which in part reflects differences in the digestibility of these foods. Typically for highly digestible human foods such as chicken breast, egg, rice or oils, the [[Nutrition Glossary#Atwater Factors|‘Atwater’ factors]] [protein (4 kcal per gram), fat (9 kcal per gram), and carbohydrate (4 kcal per gram)] can be used to calculate energy content.  

'''Foods differ in the amount of energy, and this is a primarily a function of the amount of moisture, [[Nutrition Glossary#Digestibility|digestibility]], and the amount and proportions of macronutrients'''. Digestibility (i.e. feeding) studies are the most accurate way of determining the ‘available’ energy content of a food, but these studies are expensive and require the use of laboratory animals. Many pet food companies do not have the resources to conduct digestibility studies and use '''predictive equations''' instead. There are different predictive equations for pet foods and human foods, which in part reflects differences in the digestibility of these foods. Typically for highly digestible human foods such as chicken breast, egg, rice or oils, the [[Nutrition Glossary#Atwater Factors|‘Atwater’ factors]] [protein (4 kcal per gram), fat (9 kcal per gram), and carbohydrate (4 kcal per gram)] can be used to calculate energy content.

 

 

An alternative but more complex equation which does account for differences in digestibility has been developed and this does appear to provide a better estimate of the ‘available’ energy content of the food<ref>Kienzle E, et al. The development of an improved method of predicting the energy content in prepared dog and cat food. J Anim Physiol Anim Nutr 1998; 79:69-79.</ref>.  

*'''Step 1:''' calculate carbohydrate (NFE) content:  Carbohydrate (NFE; g/100g)) = 100 - (Moisture + Protein + Fat + Ash + Crude Fibre)

*'''Step 1:''' calculate carbohydrate (NFE) content:  Carbohydrate (NFE; g/100g)) = 100 - (Moisture + Protein + Fat + Ash + Crude Fibre)

*'''Step 2:''' calculate the Gross Energy (GE) content of the food:  GE (kcal/100g) = (5.7 x protein) + (9.4 x fat) + (4.1 x [NFE + Crude Fibre])

*'''Step 2:''' calculate the Gross Energy (GE) content of the food:  GE (kcal/100g) = (5.7 x protein) + (9.4 x fat) + (4.1 x [NFE + Crude Fibre])

'''Key:'''

'''Key:'''

*GE = gross energy  

:''GE = gross energy ''

*DE = digestible energy

:''DE = digestible energy''

*DE = digestible energy

:''DE = digestible energy

*ME = metabolisable energy

:''ME = metabolisable energy

*CF = crude fibre

:''CF = crude fibre

*NFE = nitrogen free extract  

:''NFE = nitrogen free extract''

*Semi-moist (>14% and <60% moisture) provides between 250-350+ kcal per 100g;  

*Semi-moist (>14% and <60% moisture) provides between 250-350+ kcal per 100g;  

*Wet food (>60% moisture) typically provides 80-100+ kcal per 100 g.  

*Wet food (>60% moisture) typically provides 80-100+ kcal per 100 g.  

'''Since fat provides a larger proportion of energy relative to protein and carbohydrates, diets with higher fat levels will provide more energy per 100g as-fed'''. The energy contribution of total dietary fibre is negligible for dogs and cats, yet inclusion of high levels of dietary [[Fibre - Nutrition|fibre]], especially insoluble, non-fermentable fibre will increase volume of food while decreasing energy content<ref>Fahey GC Jr, et al. Dietary fiber for dogs. II. Isolated total dietary fiber (TDF_ additions of divergent fiber sources to dog diets and their effects on nutrient intake, digestibility, metabolic energy and digesta mean retention time. J Anim Sci 1990;68:4229-4235.</ref><ref>Kienzle, E, et al. Prediction of Energy Digestibility in Complete Dry Foods for Dogs and Cats by Total Dietary Fiber. J Nutr 2006;136:2041S-2044S.</ref>.

'''Since fat provides a larger proportion of energy relative to protein and carbohydrates, diets with higher fat levels will provide more energy per 100g as-fed'''. The energy contribution of total dietary fibre is negligible for dogs and cats, yet inclusion of high levels of dietary [[Fibre - Nutrition|fibre]], especially insoluble, non-fermentable fibre will increase volume of food while decreasing energy content<ref>Fahey GC Jr, et al. Dietary fiber for dogs. II. Isolated total dietary fiber (TDF_ additions of divergent fiber sources to dog diets and their effects on nutrient intake, digestibility, metabolic energy and digesta mean retention time. J Anim Sci 1990;68:4229-4235.</ref><ref>Kienzle, E, et al. Prediction of Energy Digestibility in Complete Dry Foods for Dogs and Cats by Total Dietary Fiber. J Nutr 2006;136:2041S-2044S.</ref>.

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[[Category:Nutrients]]

[[Category:Nutrients]]