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Biomedical subjects

C C Whitehead

Publications and source records attributed to C C Whitehead.

At least 91 records · Page 5Linked to original sources
PubMed1984

Development of divergent lines of lean and fat broilers using plasma very low density lipoprotein concentration as selection criterion: the first three generations.

Male and female broilers of a pure line were selected over three generations on the basis of high or low plasma very low density lipoprotein (VLDL) concentration at 7 weeks of age. Heritability of plasma VLDL was high (h2 = 0.50 +/- 0.08) and by the third generation mean values in the two lines differed by a factor of 2.5. Correlated responses to selection for low plasma VLDL included a relative decrease in abdominal fat and total body lipid and an increase in body protein, together with improvements in the conversion efficiencies of food and dietary protein. There was no difference between the lines in 7-week body weight.

Abdomen↗
PubMed1984

Objective and subjective evaluation of psychiatric ward redesign.

The authors describe the redesign and evaluation of a 30-bed psychiatric unit. The design approach was user oriented, employing a psychoenvironmental model that postulates an interaction between the physical environment and the psychotherapeutic milieu. Objective and subjective instruments demonstrated that environmental redesign based on this model correlated with behavioral changes in clinically desirable directions. These changes also correlated with reduced psychopathology and might have been facilitated by "social organizers," design solutions that encourage social interaction focused on ward activities.

Adult↗
PubMed1983

The effect of biotin deficiency and dietary protein content on lipogenesis, gluconeogenesis and related enzyme activities in chick liver.

Chicks were given biotin-deficient diets containing either suboptimal (low) or supraoptimal (high) concentrations of protein from 1-d-old until they were used during their fourth week of life. The low-protein diet predisposed chicks to develop fatty liver and kidney syndrome and the high-protein diet to develop classical biotin deficiency signs. Two other groups, as controls, received biotin-supplemented rations. Low dietary protein increased lipogenesis by isolated hepatocytes but had little effect on gluconeogenesis compared to high dietary protein. Low dietary protein decreased activities of hepatic isocitrate dehydrogenase (EC 1.1.1.42), fructose-1,6-bisphosphatase (EC 3.1.3.11) and glucose-6-phosphatase (EC 3.1.3.9; GP) and increased activities of fatty acid synthase (FAS), citrate cleavage enzyme (EC 4.1.3.8; CCE) and malate dehydrogenase (decarboxylating) (EC 1.1.1.39). When biotin deficiency was superimposed, the rate of lipogenesis by isolated hepatocytes (from fed birds) was decreased. Gluconeogenesis from lactate and glycerol was also depressed. Activity of GP was further decreased by biotin deficiency on the low-protein regimen and FAS and CCE were further increased. PK activity was increased by biotin deficiency.

Animals↗
PubMed1983

Experimentally induced fatty liver and kidney syndrome in the young turkey.

Turkeys were fed up to four weeks of age on diets of low biotin content and then fasted for 18 hours. Three birds developed clinical signs of fatty liver and kidney syndrome (FLKS) and on autopsy had pale and swollen livers and kidneys. Morphological studies showed fatty accumulations in liver, kidney, heart and proventriculus but no signs of inflammatory or degenerative changes. The infiltrated lipid had an abnormal fatty acid composition, with an increased proportion of monounsaturated fatty acids. Affected birds suffered from severe hypoglycaemia and hepatic glycogen was depleted. These findings demonstrate that FLKS can be induced experimentally in turkeys.

Animals↗
PubMed1982

The post mortem diagnosis of fatal hypoglycaemia using the fatty liver and kidney syndrome of chicks as a model.

1. The concentrations of vitreous humour and plasma glucose were closely correlated in both healthy and fatty liver and kidney syndrome-affected chicks at time of death. 2. The values of vitreous humour glucose and lactate decreased rapidly after death, such that they were not reliable indicators of the presence of hypoglycaemia immediately ante mortem. 3. Hepatic glycogen was extremely low in fatty liver and kidney syndrome-affected birds, whereas significant quantities remained in healthy birds up to at least 24 h post mortem.

Animals↗
PubMed1982

The determination of the availability to chicks of biotin in feed ingredients by a bioassay based on the response of blood pyruvate carboxylase (EC 6.4.1.1) activity.

1. Experiments were carried out to establish the conditions required for the measurement of the availability to chicks of biotin in feed ingredients by a bioassay based on the response of blood pyruvate carboxylase (EC 6.4.1; PC) activity. 2. Reference diets were formulated which gave a linear response in blood PC activity at 3 weeks of age over a wide range of supplemental dietary biotin concentrations. 3. Dietary protein concentration was found to affect blood PC activity. Hence purified ingredients in the reference diets were wholly or partially replaced by the test ingredients so that all diets in each assay contained the same amounts of protein, fat and metabolizable energy. Comparison of the blood PC activities of birds given the test diets with those given biotin-supplemented reference diets provided a measure of the available biotin content of the test ingredient. 4. Bioavailabilities of biotin were found to vary widely in the cereals and vegetable-protein sources tested.

Animals↗
PubMed1982

Interrelationships between biotin, choline and other B-vitamins and the occurrence of fatty liver and kidney syndrome and sudden death syndrome in broiler chickens.

1. Addition of supplemental choline to a biotin-deficient diet decreased the biotin status of chicks and increased mortality from fatty liver and kidney syndrome (FLKS). 2. Mortality was also increased by dietary supplementation with a mixture of other B-vitamins, excluding biotin, and was highest when the choline and B-vitamin supplements were combined. 3. The occurrence of sudden death syndrome (SDS) was unaffected by dietary biotin concentration. 4. A previously unreported condition was observed in which birds died showing post-mortem signs characteristic of both FLKS and SDS and whose occurrence was related to the biotin status of the chicks.

Animals↗
PubMed1982

The relationship between plasma triglyceride concentrations and body fat content in male and female broilers--a basis for selection?

1. The relationship between plasma triglyceride concentrations and body fat content was examined in three groups of male and one of female broiler chickens fed ad libitum on a normal growing diet. 2. Phenotypic correlations between total plasma triglyceride concentration and fat content were +0.50, +0.37 and +0.39 for the three groups of male broilers and +0.33 for the group of females. Triglyceride content of plasma very low density lipoprotein (VLDL) plus low density lipoprotein (LDL) showed similar correlations with fat content. 3. Selection of birds from a flock of 550 male broilers on the basis of high or low plasma VLDL plus LDL triglyceride concentrations produced groups with significant differences in body fat content but little difference in body weight. 4. The results suggest that measurements of plasma triglyceride concentration could be used as an indirect means of selecting for decreased body fat content in broiler breeding programmes.

Animals↗
PubMed1982

Plasma lipoprotein concentration as an indicator of fatness in broilers: effect of age and diet.

1. The relationships between plasma very low density lipoprotein (VLDL) plus low density lipoprotein (LDL) triglyceride concentrations at 3 and 7 weeks of age and body fat content at 7 weeks were studied in male and female broiler grandparent stock fed on diets containing about 25 or 90 g fat/kg. 2. Plasma VLDL plus LDL triglyceride concentrations were similar in males and females and only slightly higher in birds fed on the high-fat diet. Concentrations at 3 weeks were similar to those at 7 weeks. 3. Body fat content was correlated more closely with plasma VLDL plus LDL triglyceride measured at 7 weeks than at 3 weeks. 4. Phenotypic correlations between body fat content and plasma VLDL plus LDL triglyceride concentrations at 7 weeks were 0.47 and 0.43 for males and females respectively fed on the high-fat diet and 0.70 and 0.60 for males and females fed on the low-fat diet. 5. Phenotypic correlations between body fat content and measurements with an abdominal caliper were 0.35 and 0.49 in birds fed on the high- and low-fat diets respectively. 6. A possible procedure for selecting for leanness in broiler breeding programmes on the basis of measurements of plasma VLDL plus LDL triglycerides is discussed.

Adipose Tissue↗
PubMed1982

Plasma lipoprotein concentration as an indicator of fatness in broilers: development and use of a simple assay for plasma very low density lipoproteins.

1. A turbidimetric assay for plasma very low density lipoproteins (VLDL) was developed, based on their selective precipitation with heparin and Mg2+. 2. Measurements of plasma VLDL concentration using the turbidimetric method showed a correlation of 0.98 with plasma VLDL plus low density lipoprotein triglyceride concentration estimated chemically. 3. Correlations between plasma VLDL concentration measured turbidimetrically and body fat content were similar to or higher than those obtained previously using a chemical assay. Correlations for broiler grandparent stock fed on a low-fat diet were 0.70 and 0.65 for males and females respectively. 4. Turbidimetric measurement of plasma VLDL concentration provides a simple, rapid and effective method of estimating fatness in live broilers that could be applied to commercial broiler breeding programmes.

Adipose Tissue↗
PubMed1981

The effects of low dietary concentrations of saponin on liver lipid accumulation and performance in laying hens.

1. Feeding 4 or 5 saponin/kg diet depressed food consumption, egg and body weights and liver lipid concentrations. Rate of egg production decreased initially but later returned to normal. 2. At 1 g/kg diet saponin had no effect on food consumption or laying performance but decreased the high liver lipid concentration in two experiments on a heavy (Warren) strain of bird. There was no effect on liver lipid concentration in another experiment using a light (White Leghorn) strain in which liver lipid concentration was low. 3. Excreta lipid, liver cholesterol and plasma high density lipoprotein-cholesterol concentrations were unaffected by saponin but plasma triglyceride concentrations were decreased.

Animal Feed↗
PubMed1981

Aspects of metabolism related to the occurrence of skin lesions in biotin-deficient chicks.

1. Chicks were fed on biotin-deficient low- and high-protein diets supplemented with increasing concentrations of biotin. 2. Biotin deficiency decreased hepatic activity of pyruvate carboxylase [EC 6.4.1.1] but activity of acetyl-CoA carboxylase [EC 6.4.1.2] was comparatively unaffected. 3. Increasing dietary protein increased the severity of biotin deficiency as assessed by skin lesions and decreased plasma biotin concentrations. 4. The severity of the skin lesions over all the treatments was most closely related to plasma biotin concentration.

Animals↗
PubMed1980

Performance of laying hens fed on practical diets containing different levels of supplemental biotin during the rearing and laying stages.

1. The effect of biotin supplementation of low-biotin practical diets during rearing and laying stages on performance was studied in White Leghorn-type laying hens. 2. Biotin supplementation during rearing did not have any apparent effect on the condition of the bird at point-of-lay or on subsequent laying performance. 3. Biotin supplementation during lay did not have any beneficial effect upon egg number, egg size or food intake or food conversion efficiency. 4. Internal egg quality, as reflected by albumen height, was slightly improved by biotin supplementation of layer's diet. 5. Input-output relationships were calculated for the incorporation of biotin in egg yolk. 6. Metabolic measurements suggested that biotin concentration in egg yolk was the best criterion of biotin status in the hen. 7. It is concluded that practical diets contain sufficient biotin to support optimum egg-laying performance in hens.

Animals↗
PubMed1980

Biotin status, blood pyruvate carboxylase (EC 6.4.1.1) activity and performance in broilers under different conditions of bird husbandry and diet processing.

1. Three experiments were conducted to investigate the relationships between blood pyruvate carboxylase (pyruvate: carbon dioxide ligase (ADP-forming), EC 6.4.1.1; PC) activity, growth performance and dietary biotin level in broilers under different husbandry conditions. Blood PC activity was also used to gain information on the ingestion of biotin faecal origin by birds housed on wood shavings and the effect of steam-pelleting on the biotin content of diets. 2. Blood PC activity and relationship to dietary biotin level were similar in birds kept under different husbandry conditions. 3. Biotin requirement for growth was higher in birds kept under conditions that allowed them to reach their growth potential more fully. 4. The contribution of biotin of faecal origin to the biotin intake of birds housed on wood shavings was negligible at 3 weeks of age but by 7 weeks was equivalent to approximately 0.01 mg/kg diet. 5. Steam-pelleting did not affect the stability or availability of biotin of natural or synthetic origin in diets. 6. It is concluded that blood PC activity is a good criterion of biotin status and requirement in fast-growing broilers.

Animal Husbandry↗
PubMed1980

Blood pyruvate carboxylase activity as a criterion of biotin status in young pigs.

A basal diet containing isolated soybean protein was supplemented with 100 and 500 microgram biotin/kg and another basal diet containing hen-egg albumen was supplemented with 1300 microgram biotin/kg. The five diets were fed to groups of young pigs from four to 12 weeks old. Growth depression or skin or foot lesions characteristic of biotin deficiency were not seen but the undersurfaces of the hooves of pigs given the basal albumen diet were unusually soft. Blood pyruvate carboxylase activity showed a maximum response to dietary biotin at six weeks but by 12 weeks there was no response to supplemental levels greater than 100 microgram/kg. Plasma biotin concentration gave a good indication of biotin intake at all ages.

Administration, Oral↗
PubMed1979

Nutritional and metabolic aspects of fatty liver disease in poultry.

There are two metabolic disorders of major commercial importance in poultry that involve the occurrence of fatty deposits in the liver. Fatty Liver and Kidney Syndrome (FLKS) affects young birds and the main manifestations, lipid infiltrations into liver and many other organs, are apparently secondary effects of the primary lesion that lies in carbohydrate metabolism. Although several nutritional and environmental factors influence FLKS, the main factor is the vitamin, biotin. In the absence of an adequate supply of biotin, the hepatic activity of pyruvate carboxylase, a biotin-dependent enzyme, becomes so low that gluconeogenesis in the liver via pyruvate becomes negligible. When the bird is then subject to a mild stress and/or short term fasting, liver glycogen reserves become rapidly depleted and a progressive hypoglycaemia develops that ultimatley proves fatal. Supplementing diets with adequate amounts of biotin can prevent the syndrome. Fatty Liver Haemorrhagic Syndrome (FLHS) is brought about by an excessive accumulation of fat in the livers of adult hens which weakens the cellular structure of the liver and allows fatal haemorrhaging to occur. The aetiology of the syndrome is not clear, but a major factor is an excessive intake of dietary energy. However, the involvement of hormonal and toxicological factors, as well as other nutritional factors, is also possible.

Animal Nutritional Physiological Phenomena↗