Nutritional quality animal studies

Feeding studies with the rat as the test animal verified the high nutritional quality indicated by the amino acid pattern (45). Using isolates and concentrates prepared from Jewel and Centennial cultivars, PER values were equal to that of casein (milk protein) (Table IV). Examination of the amino acid patterns of sweet potato protein and casein revealed that both contained... 

Although significant strides have been directed at reducing fat content in food products, certain lipid ingredients and sources of fatty acids are used to enhance the health and nutritional quality of foods. For example, CLA isomers were enriched in both dairy and nondairy products to convey its anticancer and antiobesity effects that were reported repeatedly in animal studies (39). Sources of n-3 PUFAs are also added directly to infant formula to provide sufficient DHA for normal development of the nervous system during early infancy. In the United States, DHA was approved by the FDA in 2001 to be added into infant formula (40, 41). 

Microalgae were studied as a potent source for food additive, nutraceuti-cal, or pharmaceuticals. In fact, 30% of the current world algal production is used for animal feed where over 50% of the current world production of Arthrospira is used as feed supplement. It also needs to be of the correct size and shape to be ingested and to have high nutritional qualities and a digestible cell wall to make nutrients available. Protein content is a major factor determining the nutritional value of microalgae. 

Experimentation. Veterinarians in academic research laboratories and other research facilities perform experimental studies and surgeries on animals to develop new medicines, treatments, and surgeries to improve the health care available to both human beings and other animals. They also conduct nutritional and management studies to improve the quality of meat produced from animals and poultry. 

Historically, the nutrition of animals can be divided into three general areas. Initial studies in animal nutrition focused on determination of essential nutrients. This effort was followed by investigations concerned with maximizing feed efficiency in livestock to obtain the greatest product yield with minimum feed inputs. Recently, efforts have focused on dietary supplementation of livestock to improve the quality of the product subsequently obtained from food-producing animals. The term quality is broad and as used here is meant to include aspects of improved shelf-stability, consumer acceptance and food safety. 

Nutrition. Fats and oils are recognized as important nutrients for both humans and animals because they provide a concentrated source of energy, contain essential fatty acids, and serve as carriers for fat-soluble vitamins. Research studies have also indicated a relationship between saturated fats, cholesterol, and trans-isomers and the incidence of coronary heart disease. In many cases, shortening functionality can be maintained with formulations limiting cholesterol, the identified saturated fatty acids, and tran -isomers. Shortening formulation can also aid in reductions of fat consumption by development of more effective products to reduce the levels required to produce the desired functionality and finished product quality. 

Chemical Action. — Psychic influence is not, however, the sole cause of the secretion. When nutritive material is introduced into the stomach of an animal by the aid of a fistula, it is found that this food is more or less digested, indicating that the secretion is made even in the absence of all psychical intervention. The secretion produced in this last case is due to the specific action of the nutritive substances, and it is observed that the quantity and quality of the juice secreted vary with the chemical nature of the substance absorbed. Indeed, two causes regulate the secretion of the gastric juice, one of purely psychic origin, the other of chemical origin. To study the unconscious secretion, that is to say the direct effect produced by the foods on the secretorial glands, Pawlow introduced 400 g. of meat into the stomach of a dog operated upon as before. 

In our present studies we addressed three questions 1) Is the testosterone level of males an important endocrine determinant of the attractiveness of male odors to females 2) Does the nutritional history (i.e., quality) of males influence the attractiveness of their odors to females 3) Are the odor preferences of females consistent with female social and mate preferences We used the prairie vole Microtus ochrogaster), a monogamous species of arvicoline rodent, as our model species. All animals were obtained from an outbred colony maintained at Murray State University. The animals were housed on a 14L 10D light cycle at 23 2°C and fed Purina Rodent Chow 5001. Animals were weaned at 20 d of age and caged individually. No animal was tested more than once unless otherwise stated. 

Data for calculation of nutritional analyses are much the same for all methods of statistical analysis described above. Basic precautionary steps recommended for selection of individuals, pretest conditions, and standardization of both test animals and test diets have been discussed elsewhere (Berenbaum 1986). Nutritional indices are extremely sensitive to small errors in computation (Schmidt Reese 1986 Stamp 1991), thus, efforts to reduce such sources of variation are of utmost importance in such studies. All consumption experiments must provide food ad libitum unless effects of starvation are being tested, and careful planning and some preliminary experiments may be required to determine how much food must be prepared or obtained in advance to complete the entire experiment. This is especially important when insects are to be tested on plant food to avoid introducing variation in food quality due to difference in plant or leaf age into the experimental design. 

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