Food preference of young rhesus monkeys fed marginally zinc deficient diets

Zinc deprivation has been shown to produce hypogeusia in rhesus monkeys but the possible consequences of altered taste sensitivity for food preference and selection is not known. We studied 13 rhesus monkeys (2.5 to 3 years of age) for food preference in a structured choice situation. These animals were fed two levels of dietary zinc: marginally zinc deprived (fed 4 μg zinc/g diet from conception and throughout development;N=6), or control (fed a 100 μg zinc/g diet throughout the study;N=7). Preference for familiar vs unfamiliar food items, order of food preferences, persistence in retrieval of preferred and nonpreferred foods, and preference under four deprivation periods were examined. Animals were offered a choice of two food items, both containing minimal zinc levels, and food choice and latency of choice were measured. Results indicate that animals fed the marginal zinc diets had reduced preference for unfamiliar foods relative to controls and different patterns of food preference. These results may be relevant to maintenance of appropriate food selection in marginally zinc deprived populations.     

Plasma glucose and insulin levels in monkeys anticipating feeding

To see whether plasma glucose or insulin changed in anticipation of feeding, we provided seven rhesus monkeys with four-hour access to food every other day. Blood was sampled before and during a 30-minute signal which ended with food availability and before and during a 30-minute signal which was not closely and reliably linked with food availability. Plasma insulin showed no evidence of conditioning. Plasma glucose was higher during the signal than prior to the signal in both experiments. This probably reflects the arousing nature of the signal rather than appetitive-associated learning. However, the differences, while statistically significant, were probably biologically trivial because they fall within the normal fluctuations of meal-fed monkeys. Under the conditions of this experiments, it appears that conditional changes in glucose and insulin do not reliably occur in monkeys anticipating access to food.     

Plasma carnitine and cholesterol levels in monkeys and pigeons: species/breed differences and the influence of gender and diet.

1. Total plasma carnitine and cholesterol were studied in two breeds of pigeon and four species of sub-human primates. 2. The levels of plasma carnitine and cholesterol differed within species and between species and were influenced by diet and gender. 3. In the animals studied, pigeons had the highest levels of plasma carnitine (greater than 120 nM/ml) and Squirrel monkeys (Saimiri sciureus) had the lowest levels (ca. 10 nM/ml). 4. Linear regression analysis of plasma carnitine and cholesterol in the monkeys and pigeons indicated no strong correlation between these parameters.     

Tissue iron content in riboflavin and pyridoxine deficient rats

The effect of riboflavin and (or) pyridoxine deficiency and repletion on tissue iron content was studied in rats. The iron content in liver, spleen, and kidney and plasma iron concentration of riboflavin deficient (RD) rats was lower, but hematocrit was not. In pyridoxine deficient (PD) rats versus control rats, the iron content in liver was significantly higher but not in spleen and kidney. In PD rats hematocrit was lower but plasma iron concentration was not. Although combined riboflavin and pyridoxine deficient (CD) rats had lower iron content in liver and spleen compared with control rats, these values were intermediate between those of RD rats and PD rats. After RD and PD rats were repleted, the iron content in liver, spleen, and kidney returned to that of control rats, and the hematological indices were improved significantly. These results suggest that riboflavin and pyridoxine deficiency may impair the absorption and utilization of iron and may result in altered tissue iron content.     

Absorption of glyoxylate and oxalate in thiamine and pyridoxine deficient rat intestine

Dietary deficiency of thiamine or pyridoxine has been shown to produce hyperoxaluria and renal stone formation in man and experimental animals. To determine the possible contribution of exogenous glyoxylate and oxalate, the intestinal transport of [14C] - oxalate and [14C] - glyoxylate was measured in vitamin B1 and B6 deficient rats and their respective pair-fed controls. Results indicate that glyoxylate and oxalate are passively diffused from lumen to lamina propria in thiamine deficient and their pair-fed controls with no significant change in the rate of uptake of both the substrates. However B6 deficient rats showed a significant enhancement in the rate of oxalate uptake due to development of a new biphasic transport system. The rate of glyoxylate uptake by simple passive diffusion remained unaltered in pyridoxine deficiency.     

Remnant-like particle cholesterol and triglyceride levels of hypertriglyceridemic patients in the fed and fasted state

Potentially atherogenic triglyceride-rich lipoprotein (TRL) remnants can be isolated and quantitated as remnant-like particles (RLP), using an immunoaffinity gel containing specific anti-human apolipoprotein A-I (apoA-I) and apoB-100 monoclonal antibodies. The aim of the present study was to determine the relationship between postprandial changes in RLP levels and changes in total serum triglyceride (TG) in patients with different forms of hypertriglyceridemia (HTG). Three groups of patients were selected, having similarly elevated serum TG levels: a) HTG with TRL remnant accumulation (i.e., type III patients, n = 15, TG: 3.8 +/- 0.2 mm), b) HTG with increased LDL (i.e., type IIb patients, n = 15, TG: 3.7 +/- 0.2 mm), and c) HTG without evidence of remnant or LDL accumulation (i.e., type IV patients, n = 15, TG: 3.9 +/- 0.3 mm). Ingestion of a 45-g fat meal caused a significant increase in serum TG (30;-50%) in all patients. Mean serum TG levels of the three groups were not significantly different at 4 or 6 h after the meal. RLP cholesterol (C) and TG levels increased after the meal in all patients, but these postprandial increases were also not significantly different among groups. Type III patients had significantly higher (P < 0.01) levels of RLP-C and RLP-apoE in the fasted and fed state, and also had significantly higher RLP-C-to-serum TG ratios (P < 0.001) compared with the other groups. These results indicate that 1) RLP-C and RLP-TG levels are significantly increased in the fed versus fasted state in patients with elevated fasting TG levels; 2) patients with different forms of HTG, but similar TG levels, have similar postprandial increases in RLP-C and RLP-TG; and 3) type III patients have significantly elevated levels of RLP-C and RLP-apoE in both the fed and fasted state.     

Plasma cholesterol levels in free-ranging macaques compared with captive macaques and humans

Plasma total cholesterol in free-ranging Japanese macaques (Macaca fuscata) on Koshima islet and in free-ranging long-tailed macaques (Macaca fascicularis) at Pangandaran in Indonesia was found to occur at very low levels compared with captive macaques and humans. Although total cholesterol levels in captive macaques were lower than humans, differences in HDL cholesterol levels were only small. In both sexes of wild and captive Japanese macaques, total cholesterol levels decreased from birth through to young adulthood but then increased in adult females of the captive group. In contrast, the value for adult females of the wild troop remained at a low level. Low TCH levels in adult females of the wild Japanese macaque troop may be due to a low energy intake and may have caused a delay in the onset of sexual maturation. Plasma TCH levels increased with the addition of 0.1% dietary cholesterol over six weeks in captive long-tailed macaques. That the cholesterol value after six weeks was dependent on cholesterol levels prior to supplementation indicates that captive macaques are slightly saturated with cholesterol.