NUTRIENT-TO-CALORIE RATIOS IN APPLIED NUTRITION.
This paper discusses the desirability of expressing the nutrient require ments of man and animals relative to their associated energy intake, and proposes a format for expressing a dietary standard for humans. Caloric needs are known to vary with size, activity, and productive performance. There is agreement that most of the nutrients quantitatively considered in diet or ration formulation should remain in balance with each other and with energy, for optimal food efficiency. Many nutri tionists believe that it is not possible to state the requirements for individual nutrients without also specifying the amounts of others also to be ingested. In the case of nutrients that must be stored in the body, as during growth, the ratio to energy intake changes progressively to the final adult equilibrium status. In the case of the human, one adult, and 3 juvenile "diet" categories appear to be adequate, within each of which the interbalances between nutrients and that between nutrients and energy are constant. Within these 4 categories, adequate daily nutrition can be accomplished by adjustments in the intake of the diet as a whole. One of the far-reaching concepts in dietetics and animal rationing is the im portance of balance between the nutrients of the diet â€” the realization that relative excesses are no less undesirable than rela tive deficiencies. We have only begun to unravel the picture of nutrient interrela tionships, but it is abundantly clear that the efficiency of food utilization by the animal body may be markedly affected by alterations in the inter-nutrient balance, or between the nutrient and energy pattern, or both. There may be some doubt whether we yet can define the ideal interrelations, but periodically since 1810 tabulations have been made of the quantities of energy and of nutrients that evidence indicated were needed daily by farm animals accord ing to species, weight, age, sex and produc tion performance. One pertinent study was that by Guilbert and Loosli ( 1) in which they computed for farm animals and poultry from the appro priate feeding standards (NAS-NRC series) the recommended daily feed intakes, and total digestible nutrients (TDN); and per unit TDN, the digestible crude protein, calcium, phosphorus, carotene, vitamin A, vitamin D, thiamine, riboflavin, niacin and pantothenic acid for individuals at at tained weights of from 10 to 100% of expected adult size. Although their study was mostly concerned with immature growing animals, and was hampered by excessive variability partly from the fact that the NAS-NRC feeding standard values at that time contained margins of safety of unknown magnitude over the true require ments, they prepared a table of generalized recommended allowances of protein, Ã‡a,P, thiamine and riboflavin in ratio to TDN intake for farm livestock and poultry. They state, 'The feasibility of expressing (in feeding or dietary standards â€”E.W.C.) the relationship of the various nutrients with metabolizable energy rather than with total digestible nutrients should be ex plored." They also comment, "In the pre occupation of seeking new nutritional fac tors, it would appear desirable to pause when they are found to determine their fundamental relations to other nutrients, to body weight, or to caloric intakes, and the quantitative requirements in a sys tematic procedure." Because of incomplete knowledge, the authors of the early tabulations often claimed as requirements, nutrient values later shown to be excessive; and it is sig nificant that, other than inclusion of addi tional nutrients, the chief changes in the chronologically successive "standards," even though by different authors, have been downward revisions of the amounts of nutrients believed to be required rela tive to energy intake. The criteria for such changes have been: increased effi ciency of the ration in producing growth, fattening, milk or egg production, or deReceivedfor publicationAugust8, 1963. J. NUTRITION, 82: '64 353 D ow naded rom http/academ ic.p.com /jn/article-at/82/3/353/4777993 by gest on 19 M arch 2019
Protein in Nutrition
The treatment of patients in groups can now be regarded as an essential part of the psychotherapist's equipment. As in the case of individual therapy, the procedures vary as widely as psychotherapists' attitudes to the behaviour disorders. The editor of this volume-one of the best-known American workers in this field-and his contributors follow psycho-analytic thought, for the methods described most fully are those founded on the appreciation of transference relationships and in particular on the adequate treatment of the hostile feelings that enter into these relationships. Slavson and his co-workers have developed two main methods -activity group therapy and interview group therapy. In the first, which is for children, the therapist provides a socially tolerant environment in which dominant themes of the inner world can be acted out. The therapist does little or no interpretation, and the modifications in the child's inner world which enable him to improve his relations with his outer world take place by the acting-out process in the " permissive " environment. The second Method, the one of choice for adults, consists in spontaneous discussions by the group. Here the therapist makes interpretations through which the members gain insight into, and hence release from, their difficulties. The actual processes within groups conducted along these two main lines are clearly described in a series of contributions on a variety of psychological disturbances. Those starting to give group treatment will regret the omission of a detailed account of how adult groups are begun-how to introduce the idea of group treatment and to conduct the opening sessions. The writers confirm the view that group therapy in skilled hands has very great potentialities. Equally, they expose the fact that much critical thought and systematic study are needed on both principles and practice. It is not at all clear, for example, why the composition of groups has to be so carefully planned. Again, in the interview-therapy method it is difficult to see why "relationship group therapy " is described as a distinct variant. The latter method is characterized by the analysis of the transference relationships between members of the group and between them and the therapist. But if the basic principles of psycho-analysis are accepted-and it is stated that these are fundamental to all brands of psychotherapy-we may ask whether the members of a group can achieve full insight into their difficulties without these interpretations. How else can the innumerable projections and other unconscious manipulations of the relationships in the group be brought to the patients' awareness ? Moreover, in the acting-out process of activity therapy it is difficult for a psycho-analyst to imagine an unconscious need-system undergoing a radical change unless the patient gains insight through interpretation. The cases quoted certainly seem to have benefited, but it is not clear whether the improvement is the result of acting-out or of the interpretations that must have been given by other members of the group. Spontaneous testing of fantasy against reality is one of the most important ways in which the child's personality develops, so that there is no question of denying the possible effects of such a process. It is therefore puzzling to read that pre-school children, in whom the acting-out process would normally be most prominent, are not suited to activity therapy since they apparently have to be given insight through interpretation. It is possible that the methods of describing the cases suitable for activity therapy and interpretative procedures are not adequate. These and many other points are no doubt in the minds of the writers, who are to be congratulated on their pioneering work in this very complicated subject. This is a most useful volume for all psychotherapists, and a~special word of praise is due to the editor on the way he has obtained a unified work by applying his subject to his contributors. J. D. SUTHERLAND. PROTEIN IN NUTRITION |
Avian infectious bronchitis.
Avian infectious bronchitis (IB) is caused by the gammacoronavirus infectious bronchitis virus (IBV). The virus causes infections mainly in chickens and is a significant pathogen of commercial meat and egg type birds. IB is an acute, contagious disease characterised primarily by respiratory signs in growing chickens. In hens, decreased egg production and quality are often observed. Some strains of the virus are nephropathogenic and produce interstitial nephritis and mortality. The severity of IBV-induced respiratory disease is enhanced by the presence of other pathogens, including bacteria, leading to chronic complicated airsacculitis. Diagnosis of IB requires virus isolation or demonstration of viral nucleic acid from diseased flocks. Demonstration of a rising serum antibody response may also be useful. The widespread use of live and inactivated vaccines may complicate both the interpretation of virus isolation and serology findings. The occurrence of antigenic variant strains may overcome immunity induced by vaccination.