Protein-sufficient Diet Research Articles

"Social influences on the selection of a protein-sufficient diet by Norway rats (Rattus norvegicus)": Correction to Beck and Galef (1989).

"Social influences on the selection of a protein-sufficient diet by Norway rats (Rattus norvegicus)": Correction to Beck and Galef (1989).

Social influences on the selection of a protein-sufficient diet by Norway rats (Rattus norvegicus).

Investigated effects of interactions between naive and knowledgeable rats (Rattus norvegicus) on selection of a nutritionally adequate diet by the naive. We found that during a 7-day test, isolated rats choosing among 4 foods, 3 of which were protein-deficient and 1 of which was protein-rich, failed to learn to prefer the protein-rich diet and lost weight. Conversely, those rats that interacted with conspecifics trained to eat the protein-rich diet developed a strong preference for that diet and thrived. The authors also found that Ss were more strongly influenced in their diet selection by the flavor of the foods eaten by conspecifics than by the locations where conspecifics fed. The results suggest that social influence may be important in development of adaptive patterns of diet choice by rats (or other dietary generalists) that need to find nutritionally adequate diets in demanding environments. Students of dietary self-selection have described two complementary processes that may lead animals foraging in the world outside the laboratory to select nutritionally adequate foods from among the myriad potentially ingestible, beneficial, toxic, and useless substances found in natural habitat. First, animals have the ability to detect the presence of some nutrients in complex foods and can use tastes associated with those nutrients to select valuable foods to eat (Richter, 1943; Rozin, 1976). Second, animals can associate the postingestional consequences of a food with its taste and can, therefore, learn to select foods that provide valuable nutrients (Booth, 1985; Harris, Clay, Hargreaves, & Ward, 1933; Rozin, 1976). In the literature, these two abilities—the ability to detect directly some nutrients in foods and the ability to learn about the nutritional value of foods from the consequences of their

Social influences on the selection of a protein-sufficient diet by Norway rats (Rattus norvegicus).

Social influences on the selection of a protein-sufficient diet by Norway rats (Rattus norvegicus).

Increased resistance to Salmonella infection of hypoferremic mice fed a low-protein diet.

BALB/c and CBA/CA mice fed a protein-deficient diet developed a plasma hypoferremia corresponding to a 30 percent lowering of serum iron concentration. This hypoferremia persisted as long as the diet was maintained. Hypoferremic CBA/CA mice had increased resistance to Salmonella typhimurium C5 infection, as shown by the reduced lethal activity and the decreased growth of the bacteria in the spleen and in the peritoneal exudate of the deficient animals. This induced resistance was abolished after injection of iron or Desferal into the restricted animals. Such resistance was not observed with BALB/c mice fed a protein-deficient diet, in spite of the plasma hypoferremia. The growth of S. typhimurium C5 in the spleen and in the peritoneal exudate of these animals did not differ from the growth observed in control animals fed a protein-sufficient diet. This study suggests that hypoferremia induced by a protein-deficient diet is probably involved in the enhancement of resistance of CBA/CA mice to Salmonella infection, and that the phenomenon is host-strain dependent.

Protein Reserve Dynamics in Postbreeding Adult Male Redheads

-Labile protein reserve dynamics were studied in postbreeding adult male Redheads (Aythya americana) at Lake Winnipegosis, Manitoba, from 1974 to 1977. Changes in tissue masses were related to molt and behavioral activity. Total body protein fluctuated seasonally but tended to increase from breeding to late fall. Redheads did not increase foraging time to meet the nutritional demands of the simultaneous wing molt. Protein Reserve Index (PRI) increased from the late premolt period to the first half of the flightless phase each year. Losses in breast muscle from late premolt to early wing molt were not compensated by the increasing weight of leg muscles. Breast protein may have shifted to growing feathers or other concurrent tissue growth. Breast muscle gained weight over the latter half of the flightless phase in 1977. Changes in locomotor muscle size were related to overall PRI, foraging time, and anticipated seasonal use rather than simply use-disuse phenomena. Non-breeding male Redheads maintained significantly higher PRI from breeding to late molt and appeared to more easily meet seasonal protein requirements than birds which had bred previously. Protein reserves are maintained by many birds, not as a specialized storage product (Fisher 1954) but as muscle sarcoplasm (Kendall et al. 1973), and may be used for breeding (Jones and Ward 1976, Milne 1976, Korschgen 1977), or molt (Hanson 1962, Newton 1968, Hanson and Jones 1976). The timing of accumulation and utilization of protein reserves in waterfowl appears to have evolved with temporal predictability of food supplies, time constraints on foraging, and predation pressure. Arcticnesting geese have adapted to food shortage through almost total reliance upon reserves during nesting (Barry 1962, Ankney and MacInnes 1978, Raveling 1978). Goslings and adult females can thereby take advantage of temporarily abundant food and continuous daylight for rapid growth and reserve replenishment (Harwood 1975). In contrast, most ducks breed at lower latitudes, are smaller, and rely much more on dietary protein (Krapu 1974, 1981; Swanson et al. 1974; Serie and Swanson 1976; Drobney 1982). Heavy predation on nests has led to complete dependence on internal protein for successful reproduction in Common Eiders (Somateria mollissima; Milne 1976). Little is known about mobility of protein reserves outside the breeding season. The simultaneous remigial molt is alluded to as a period of great stress in waterfowl because many species weigh the least at this time (Weller 1957, Hanson 1962, Hanson and Jones 1976). Conversely, Ankney (1979) and Raveling (1979) have shown that female Lesser Snow Geese (Chen caerulescens caerulescens) and Canada Geese (Branta canadensis) are lightest during incubation and Ankney has argued that having less tissue is adaptive during molt because large reserves need not be maintained in view of a highly predictable, proteinsufficient diet. Hanson (1962) attributed leg hypertrophy during molt of Canada Geese to increased use but suggested that breast muscle atrophy results from the transfer of essential sulfur-containing amino acids (cystine, methionine) from temporarily unneeded breast muscle to growing remiges. Hanson and Jones (1976) found that the mass of the leg muscle increases before the flightless phase. They proposed that reciprocal changes in muscle groups do not result from use-disuse phenomenon, but are evolutionary adaptations to the flightless phase. Ankney (1979) suggested that diet of molting Lesser Snow Geese is not deficient in protein, and attributed compensatory changes in muscle groups to use-disuse. Harwood (1977) considered the arctic food supply to be nutrient-poor for Snow Geese and found variations in feeding behavior which were a compromise between maximizing daily protein intake and brood survival. Raveling (1979) concluded that both hypotheses could have validity in explaining similar changes in molting Cackling Geese (B. c. minima). He also suggested that the phenomenon occurs mainly in males because females eat enough to meet protein requirements. At the center of this controversy is the question of whether birds lack protein during molt (Ankney 1979). It is difficult to demonstrate a deficit when average baseline levels are un-

Serum and tissue thiocyanate concentrations in growing pigs fed cassava peel or corn based diets containing graded protein levels

Thiocyanate concentrations of serum, liver, kidney, spleen and longissimus dorsi were determined in 64 growing Large White × Landrace pigs offered 8 experimental isocaloric diets containing different levels of cassava peel and crude protein. Cassava peel increased serum thiocyanate on day 60 ( P<0.01) and day 90 ( P<0.01) of the trial, while the crude protein level increased it (P<0.05) on days 3G0and 90, respectively. Interaction of the two factors was significant on day 30 ( P<0.05) and day 90 ( P<0.05). There was a correlation between cyanide intake and serum thiocyanate level. Coefficient of determination revealed that cyanide alone accounted for 28.5; 60.6 and 48.8% variation in serum thiocyanate on days 30, 60 and 90, respectively. Liver, spleen and longissimus dorsi thiocyanate were affected by dietary protein intake ( P<0.05). Thiocyanate concentration was higher ( P<0.05) on cassava peel diet. Generally, crude protein at 5% reduced organ and muscle thiocyanate concentrations. A diet containing 112.2–117.3 mg/kg hydrocyanic acid (HCN) affected serum but not organ and muscle thiocyanate in protein-sufficient diets.

Effect of Cross-Fostering Rats at Birth on the Normal Supply of Essential Fatty Acids during Protein Deficiency

The effect of protein deficiency on the activity of Δ6 desaturase in the mother during lactation was determined in the liver microsomal fraction and the fatty acid composition of milk lipids from the analyzed stomach contents. The activity of Δ6 desaturase was profoundly affected by protein deprivation during pregnancy and only reached the values of controls at about 10 days after parturition. This fact did not affect the fatty acid pattern of milk lipids and no significant differences in the contents of arachidonic acid were detected between the two groups. Nevertheless, protein deficiency apparently affected milk production. The effects of protein deprivation on the supply of polyenoic acids of cross-fostering rats at birth from protein-deficient to proteinsufficient diets and vice versa, and rats maintained during pregnancy and lactation on a low protein or control diet were examined. The fatty acid pattern of liver phospholipids of the four groups under study was determined and used as a biochemical parameter for evaluating polyenoic acid status. Protein deficiency markedly affected the fatty acid pattern of liver phospholipids. A significant decrease of both arachidonic and docosahexaenoic acids was observed. This fatty acid pattern was reversed when protein-deficient animals were placed on the control diet at birth. On the other hand, the fatty acid composition of controls was negatively affected by cross-fostering to a deficient diet. The findings from the present experiment provide evidence that the negative effect of protein malnutrition appears to be promoted at least in part, by the effect of protein depletion on the supply of polyenoic acids for normal development and metabolic adaptations.

Studies on Experimental Cadmium Poisoning

Male rats of Wistar strain were separated into eight groups and various synthetic diets were given to each group. Group I was fed a high protein and calcium sufficient diet, Group II a low protein and calcium sufficient diet, Group III a high protein, calcium sufficient and cadmium added diet, Group IV a low protein, calcium sufficient and cadmium added diet, Group V a high protein and calcium deficient diet, Group VI a low protein and calcium deficient diet, Group VII a high protein, calcium deficient and cadmium added diet. A low protein, calcium deficient and cadmium added diet was given to the VIII group.After 4 weeks of these dietary regimens the rats were sacrificed and examined roentgenographically. Various tissues were removed and utilized for determination of cadmium, calcium, magnesium and zinc.The most remarkable X-ray finding was the abnormal curvature of the spinal column. Rats of I to VII groups had normal cervicodorsal lordosis and dorsolumbar kyphosis. In contrast, cervicodorsal lordosis and dorsolumbar kyphosis as well as scoliosis increased markedly in group VIII.Cadmium levels increased and magnesium and zinc levels decreased in bones of cadmium administered group III, IV, VII and VIII. Calcium levels in red muscle (soleus) and white muscle (gastrocnemius) were significantly elevated in group VIII.

Crambe seed processing: decomposition of glucosinolates (thioglucosides) with chemical additives.

AbstractCrambe meal was cooked with a variety of bases and metal salts to study decomposition of the undesirable glucosinolate (thioglucoside),epi‐progoitrin. Salts of iron and copper were preferred because they were the most active decomposers and because they did not reduce the lysine content as did the alkalies. An unsaturated hydroxy nitrile, representing about 25 mole per cent of the decomposedepi‐progoitrin, was the major reaction product left in the cooked meal. A thionamide product, representing about 7 mole per cent of the decomposedepi‐progoitrin, was also observed in meals cooked with metallic salts. The thionamide was relatively unstable in moist, hot crambe meal, especially at basic pH, and may therefore be an intermediate in a complex decomposition path. Rats fed ferrous sulfate‐treated crambe meal as 30% of a protein sufficient diet gained 70% compared with a basal control. Enlargement of thyroid, liver and kidneys was about 1.5 times that of the control organs. A crambe meal heated under the same conditions but without ferrous sulfate and fed at the same diet level caused 100% mortality within two weeks.