Quinton R. Rogers

Food intake: Regulation by plasma amino acid pattern

Abstract Food intake of rats fed diets containing a large amount of indispensable amino acids low in the growth limiting one was reduced 40–50% below that of the control in normal or cannulated rats infused with saline. When the growth limiting amino acid was infused, the food intake of the carotid artery-cannulated rats was not depressed, while the limiting amino acid infused into the jugular vein did not prevent the marked reduction in food intake of rats fed the imbalanced diets. These results provide evidence for a food intake regulatory function of some portion of the brain which is sensitive to the concentration of the growth limiting amino acid in blood.

Effect of Fish Oil, Arginine, and Doxorubicin Chemotherapy on Remission and Survival Time for Dogs with Lymphoma A Double-Blind, Randomized Placebo-Controlled Study

Polyunsaturated n‐3 fatty acids have been shown to inhibit the growth and metastasis of tumors. This double‐blind, randomized study was designed to evaluate the hypothesis that polyunsaturated n‐3 fatty acids can improve metabolic parameters, decrease chemical indices of inflammation, enhance quality of life, and extend disease free interval and survival time for dogs treated for lymphoblastic lymphoma with doxorubicin chemotherapy.

Food intake and preference of olfactory bulbectomized rats fed amino acid imbalanced or deficient diets

Abstract Olfactory bulbectomy abolished the avoidance of certain artificially flavored diets fed to rats. However, olfactory bulbectomized animals markedly curtailed their food intake as did the intact controls when fed the amino acid imbalanced or deficient diet (threonine or isoleucine limited or missing) but not the corrected diet (threonine or isoleucine supplemented). Both bulbectomized and intact animals also reduced their food intake of a high protein (75% casein) diet. Bulbectomized rats, as did the intact animals, selected a protein-free diet over the imbalanced or deficient diet but chose the basal or the corrected diet over the protein-free diet. An intact olfactory bulb is thus not essential in the control of feeding in rats fed diets involving amino acid imbalance or deficiency or protein in excess.

Effect of oral administration of L-lysine on conjunctivitis caused by feline herpesvirus in cats

OBJECTIVE To determine whether oral administration of L-lysine to cats would lessen the severity of conjunctivitis caused by feline herpesvirus (FHV-1). ANIMALS 8 healthy young adult cats. PROCEDURE Cats received oral administration of lysine monohydrochloride (500 mg, q 12 h) or placebo (lactose) beginning 6 hours prior to inoculation of virus. The left conjunctival sac received a 50-microl suspension of FHV-1 grown in cell culture (1.8 X 10(8) tissue culture infective dose50) on day 1. Cats were evaluated and scores given for clinical signs each day for 21 days. Samples for virus isolation were collected from the eye and throat every third day. Plasma lysine and arginine concentrations were measured prior to the study and on days 3, 14, and 22. RESULTS Cats that received lysine had less severe conjunctivitis than cats that received placebo. Virus isolation results did not differ between the groups. Plasma lysine concentration was significantly higher in cats that received lysine, compared with control cats, whereas plasma arginine concentrations did not differ between groups. CONCLUSIONS AND CLINICAL RELEVANCE Oral administration of 500 mg of lysine to cats was well tolerated and resulted in less severe manifestations of conjunctivitis caused by FHV-1, compared with cats that received placebo. Oral administration of lysine may be helpful in early treatment for FHV-1 infection by lessening the severity of disease.

Feeding behavior of the cat fed laboratory and commercial diets

Abstract Using a continuous recording computerized system, an experiment was conducted to examine the feeding and drinking patterns of the cat. Four diets; 1), dry commerical; 2), canned commercial; 3), casein based purified cats during 8 consecutive 7–10 day periods. Mean daily dry matter intake was greater (P

Norepinephrine and amino acids in prepyriform cortex of rats fed imbalanced amino acid diets

Monoamines and amino acids were measured in anterior prepyriform cortex (PPC) and anterior cingulate cortex (CC) of male Sprague-Dawley rats after they were offered basal, imbalanced (IMB) or corrected amino acid diets, limited in threonine (THR) or isoleucine (ILE). In the THR study, brains were taken after 2.5 hr of feeding, when intake of THR-IMB was just depressed. In the ILE study the brains were taken after 3.5 hr on ILE-IMB, a less severely imbalanced ration, before the onset of food intake depression. The PPC has been shown to be involved in the acute response of animals to imbalanced amino acid diets. In the PPC from the IMB diet groups, NE was reduced by 30%, but the other monoamines were unchanged. In CC, an area involved in the adaptive, but not the acute feeding response to imbalanced diets, the monoamines were unchanged in the IMB diet groups. In both studies, in both tissues, the limiting amino acids were decreased in the IMB groups, although the decrease of ILE in the CC failed to reach significance. The remaining indispensable amino acids, added to create the imbalance, were slightly reduced in the THR-IMB group, but not in the ILE-IMB group in both tissues. Thus, the amino acid patterns were altered in the PPC and CC, as they are in whole brains from animals fed imbalanced amino acid diets. These results also suggest that the concentration of NE in the PPC may be associated with the initial food intake response of animals to imbalanced amino acid diets.

Effect of anterior prepyriform and medial amygdaloid lesions on acquisition of taste-avoidance and response to dietary amino acid imbalance

Abstract Rats with bilateral lesions of the anterior prepyriform cortex or medial amygdala demonstrate attenuated behavioral sensitivity to a dietary threonine-imbalance. While rats with medial amygdaloid lesions demonstrate an attenuated ability to acquire taste-avoidances, such a deficit is not found in rats with lesions of the anterior prepyriform cortex. The effect of anterior prepyriform and medial amygdaloid lesions on behavioral sensitivity to dietary amino acid imbalances is discussed in terms of the probable roles played by these areas in amino acid intake control.

Effect of amygdaloid lesions on dietary intake of disproportionate amounts of amino acids

Abstract Male rats with bilateral electrolytic lesions in the anterior, medial or posterior aspects of the ventral amygdala and groups of intact rats were fed, in turn, basal, imbalanced or deficient amino acid diets involving threonine or isoleucine as the limiting amino acid, and then a low protein (6% casein) followed by a high protein (75% casein) diet. No change in food intake was observed in animals fed the threonine basal diet postoperatively. When the threonine or isoleucine imbalanced diet was substituted for the respective basal diet, animals with lesions in certain areas of the medial amygdala showed little or no depression in food intake of the imbalanced diets, while all other rats with amygdala lesions reduced their food intake markedly, as did intact controls, when fed such diets. All animals, however, curtailed their food intake of the deficient or high protein diets. The lack of responsiveness of the animals with medial amygdaloid lesions to the imbalanced diets suggests that these areas may be involved in a system regulating food intake of animals fed diets containing imbalanced amino acid mixtures.

DIET COMPOSITION AND BLOOD VALUES OF CAPTIVE CHEETAHS (ACINONYX JUBATUS) FED EITHER SUPPLEMENTED MEAT OR COMMERCIAL FOOD PREPARATIONS

Abstract Nutrition most certainly affects health and may play a role in the etiology of growth and reproductive problems in captive cheetah (Acinonyx jubatus) populations. The objective of our research was to examine nutritional differences between two dietary regimens and quantify their physiologic effects on cheetahs held in captivity. Twelve cheetahs were randomly assigned to either a commercial diet (COM) or a supplemented meat diet (SMD) group. These cats were physically examined and had blood samples taken three times over the course of a year. Representative samples of COM and four separate components of the SMD treatment were analyzed over the same time frame for proximate nutrient composition, digestibility, and concentrations of taurine, fat-soluble vitamins, and selected minerals. Concentrations of fat, vitamins A and E, Se, Fe, Cu, Na, and Mn were significantly higher in COM compared with those in SMD samples, with the exception of fat content in turkey. Mg content was lower in COM than in SMD; other nutrients did not differ. Mean concentrations of vitamins A and E in COM were markedly higher than in SMD samples (408,140 vs. 29,696 IU/kg dry matter [DM] and 431 vs. 48 IU/kg DM, respectively) and varied dramatically between sampling periods. Percent crude protein and protein-to-fat ratios were high for SMD compared with either whole prey–based or commercial food preparations. Blood urea nitrogen and serum creatinine levels were above normal reference means for domestic cats. Plasma concentrations of vitamins A, D, and E were significantly higher in COM-fed than in SMD-fed cheetahs. Both plasma retinol and tocopherol levels were almost three times higher in COM-fed cats (1.26 ± 0.06 vs. 0.53 ± 0.03 μg/ml and 17.5 ± 0.7 vs. 6.4 ± 0.02 μg/ml, respectively) and exceeded the normal ranges expected for domestic felids. Significant differences between male and female cheetahs were found for plasma concentrations of vitamin E, Se, and Fe after allowing for effects of diet and time of collection. Excess fat-soluble dietary vitamins can result in direct toxicities as well as nutrient antagonisms and may be linked to reproductive and health issues in captive cheetahs. The high protein levels found in SMD may be linked to chronic renal disease, which was detected in some of these cheetahs.

The role of palatability in the food intake response of rats fed high-protein diets.

Male albino rats, trained to eat over a 3-h period, reduced their food intake from 0.38 +/- 0.04 g of a low-protein diet to 0.14 +/- 0.03 g of a high-protein diet, within 1 min following diet presentation. Since this occurred before the metabolic effects of a high-protein diet should be seen, we suggest that, although neophobia could play a role, poor initial palatability may be a significant factor in this early depression in food intake. To differentiate initial palatability from responses to metabolic feedback, we designed a feeding paradigm using positive or negative taste cues and a 6-h feeding period. Pre-treatment with a 6% casein diet containing 0.15% quinine HCl resulted in near equal consumption of a 75% casein and a 6% casein unadulterated diet during the first 30 min after introduction of the diets. Later, the rate of consumption of the high-protein diet was lower than of the lower-protein diet, likely the result of post-absorptive factors. We suggest that prevention of the early reduction in food intake due to initial palatability may facilitate study of post-absorptive response(s) to high-protein diets.