Technical report for industrial guidelines of veterinary and food processing industries from a vitamin ingredients manufacturer.
"Under practical feeding situations, only humans, nonhuman primates, guinea pigs and fish will develop vitamin C deficiency if diets are lacking in the vitamin"
"However, with nutritionally unbalanced diets, relative vitamin C deficiency may be induced in vitamin C-synthesizing animals as well (Ginter, 1970). Low blood ascorbic acid can be caused by various types of stress, including metabolic disorders, improper nutrition, insufficient vitamin A or beta-carotene intake, and various infectious diseases. Under such conditions, dietary and injectable vitamin C can have a positive effect in vitamin C-synthesizing species. Some researchers have claimed that various diseases of the dog may be associated with insufficient vitamin C. Furthermore, skeletal diseases such as hypertrophic osteodystrophy (HOD), hip dysplasia and a number of others, particularly those common in the large and giant breeds, have been said by some to resemble ascorbic acid deficiency (scurvy). Overall, the data indicate that reduced serum vitamin C is relevant in acute HOD and that supplementary ascorbic acid can be used as a preventive and for treatment. However, such treatment may not be rewarding since there are apparently other interacting mechanisms in the HOD syndrome (Ralston Purina, 1987). A study reported prevention of hip dysplasia (German shepherds) with megadoses of vitamin C given to mothers during pregnancy and after birth to puppies until young adulthood (Strombeck, 1999). The mothers received 2 to 4 g of vitamin C per day and the puppies from 0.5 to 2 g."
There have been a number of uncontrolled clinical reports purporting to identify either scurvy in dogs or a clinical response to ascorbate supplementation of dogs infected with canine distemper, exhibiting hypertrophic osteodystrophy, hip dysplasia, or other conditions. In a series of controlled experiments that provided vitamin C to puppies infected with either canine herpes virus, kennel cough or canine hepatitis, Sheffy (1972) found no evidence of a beneficial effect of vitamin C on these disease conditions.
Small quantities of vitamin C are sufficient to prevent and cure scurvy. However, larger quantities may be required to maintain good health during adverse environmental and physiological stress as well as certain disease conditions. In recent years, antioxidant vitamins (vitamin C along with vitamin E and beta-carotene) have received a great deal of attention in that they play important roles in animal and human health by inactivating harmful free radicals produced through normal cellular activity and from various stressors. Recommendations for daily antioxidant fortification rates for dogs and cats of vitamin E, vitamin C and beta-carotene have been suggested by Parr (1996). For example, the daily vitamin C recommended supplemental level for a 13.6 kg (30 lb) dog is 60 mg and for a 2.7 kg (6 lb) cat is 12 mg.
Based on the available evidence, no requirement for vitamin C as a nutrient in the diet of dogs of cats is proposed (NRC, 2006). Vitamin C may improve the stability of other nutrients in the diet and may have functions associated with protection against oxidative damage.