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Biomedical subjects

D Balnave

Publications and source records attributed to D Balnave.

At least 37 records · Page 2Linked to original sources
PubMed1989

Egg shell quality responses of pullets given saline drinking water at different ages.

1. Saline drinking water given to pullets before sexual maturity had no effect on their subsequent egg shell quality. 2. Hens receiving saline drinking water from or after laying their first egg produced significantly more egg shell defects than hens receiving town water. 3. The production of eggs with defective shells occurred more rapidly when saline drinking water was given to 40-week-old hens than to hens during the first few weeks of lay. 4. The high incidence of egg shell defects resulting from the use of saline drinking water was reduced to control levels when hens in early lay were given town water for 5 weeks. This response was not observed with 40-week-old hens.

Age Factors↗
PubMed1988

Influence of dietary energy, nutrient density and environmental temperature on pullet performance in early lay.

1. Alterations in dietary metabolisable energy (ME) concentration had a limited influence on food and nutrient intakes and egg mass output of hens in early lay kept at the prevailing air (10 degrees to 24 degrees C), cold (6 degrees to 16 degrees C) or hot (25 degrees to 35 degrees C) temperatures. 2. Energy intakes were not improved by increasing the dietary concentrations of nutrients other than energy. 3. At prevailing air and cold temperatures all dietary ME-nutrient density combinations allowed hens to meet the recommended daily protein intake but only hens fed the most concentrated diets were able to meet this recommendation at hot temperatures. 4. Even the highest intakes of ME and protein achieved at hot temperatures failed to increase egg mass output to the values attained on any diet at cold temperatures.

Animals↗
PubMed1987

Growth performance and concentrations of thyroid hormones and growth hormone in plasma of broilers at high temperatures.

Responses of broiler chickens to a high ambient temperature (35 degrees C) were measured in two experiments. In one experiment temperatures were increased abruptly from 21 degrees C to a daily range of 21-35 degrees C whereas, in the other, temperatures were increased more gradually over 6 days. The high temperatures were maintained for 5 h/day. In both experiments, birds exposed to the high temperatures ate less food and gained less liveweight than birds maintained at 21 degrees C. Efficiency of food conversion to liveweight gain and body composition were not affected by high temperature but there was a tendency for thyroid weight to decrease. Overall, the plasma concentration of triiodothyronine (T3) decreased and the plasma concentration of thyroxine (T4) increased, resulting in a decreased T3/T4 molar ratio, during exposure to high temperature. The concentration of plasma growth hormone, but not plasma reverse T3, was increased by high temperature. The initial responses to increased temperature were variable, with birds exposed more gradually adjusting relatively well until the maximum temperature was increased to 35 degrees C. All heated birds readjusted quickly to the daily reduction in temperature to 21 degrees C.

Animals↗
PubMed1987

The relation between sodium chloride concentration in drinking water and egg-shell damage.

1. A significant linear increase in egg-shell defects from 60-week-old laying hens, and corresponding significant linear decreases in various egg-shell-quality measurements, were observed in response to increasing concentrations of sodium chloride in the drinking water, to the maximum concentration of 600 mg/l used in the present study. 2. The incidence of damaged egg shells was increased 3-fold by including NaCl in the drinking water at a concentration of 600 mg/l. 3. Shell defects declined when birds were placed on normal water for 5 weeks but were still 1.4- to 2.1-fold greater than control values. 4. After an induced rest from lay on normal water, shell defects were still 1.3- to 3.2-fold greater in birds which had previously received the NaCl in the drinking water. 5. The increased incidence of shell damage was not related to decreased food intake or increased egg weight or production.

Animals↗
PubMed1986

Free-choice feeding of broilers at high temperatures.

Broilers fed complete diets to 21 but not 44 d of age grew faster with a better efficiency of food utilisation than broilers given a free-choice selection of the cereal and protein components. When finisher diets, varying in metabolisable energy (ME) and amino acid:ME ratios, were fed at high ambient temperatures (25 to 35 degrees C) broilers on the free-choice system selected similar amino acid:ME intake ratios, which were lower than the ratios contained in the complete diets. Differences in broiler performance between 22 and 44 d of age reflected variations in ME rather than amino acid intake.

Animal Nutritional Physiological Phenomena↗
PubMed1985

Effect of dietary amino acids and metabolisable energy on the performance of broilers kept at high temperatures.

Increasing dietary metabolisable energy (ME) at particular amino acid: ME ratios significantly improved growth and food utilisation of broilers kept at moderate (18 to 26 degrees C) and high (25 to 35 degrees C) ambient temperatures during the finishing period from 22 d of age. The optimum amino acid: ME ratio varied with dietary ME concentration in the hot, but not in the moderate environment. Relatively greater increases in food intake and growth rate occurred in the hot environment when dietary ME was increased and the amino acid: ME ratio was reduced. The minimum rate of food intake did not coincide with the period of maximum temperature. Increasing the dietary protein at particular ME concentrations had little or no effect on the food intake and growth rate of birds kept at high temperatures. Supplementation with dietary fat had no beneficial effect on performance at high temperatures. The rectal temperatures of birds in the hot environment increased with age and, towards the end of the finishing period, when higher energy diets were fed.

Age Factors↗
PubMed1985

Interactions between wheat and other dietary cereals with respect to metabolisable energy and digestible amino acids.

Small, varying improvements in apparent ileal amino acid digestibilities were obtained when wheat was combined with certain other cereals in broiler diets. Synergistic interactions, sometimes resulting in large improvements in the apparent metabolisable energy (AME) contents of the diets, were also observed with certain cereal combinations. Combining wheat with maize or oats enhanced the utilisation of dietary energy and amino acids.

Amino Acids↗
PubMed1985

Nutritional significance of different fat sources for growing broilers.

Increasing the dietary supplementation of a number of fats and oils from 30 to 90 g/kg improved the growth rate and feed conversion of broilers without significantly increasing carcass fat content. Optimum growth responses were obtained with vegetable oils. The concentrations of linoleic acid or unsaturated fatty acids in animal tallows may have a greater nutritional significance than the concentrations of free fatty acids.

Animals↗
PubMed1984

Growth and carcass composition of broilers fed sunflower oil and olive oil.

Sunflower and olive oils were fed at the same dietary inclusion levels to male broilers as a means of varying the dietary linoleic acid concentration while maintaining similar concentrations of total fat and total unsaturated fatty acids. The type of oil and the dietary supplementation level influenced growth rate, food utilisation and carcass composition. Birds grew faster and utilised food more efficiently when fed the sunflower oil and had higher concentrations of body fat. Increasing the level of supplementation with either oil decreased body fat content. The different responses to the two oils were not related to differences in dietary amino acid balance, ME: protein ratios or rates of food passage through the digestive tract.

Animals↗
PubMed1984

The influence of environmental temperature, age and sex on the digestibility of amino acids in growing broiler chickens.

The ability of the broiler chicken to metabolise energy and to digest and absorb amino acids increased from 30 to 50 d of age. Although sex had no major effect on metabolisable energy or amino acid digestibilities at these ages, the influence of environmental temperature on amino acid digestibilities appeared to be sex-related, there being decreased digestibilities of most amino acids at higher temperatures in female but not male birds.

Age Factors↗
PubMed1980

The influence of tungsten on the molybdenum status of poultry.

1. Large doses of tungsten, administered to the chick either by injection or by feeding, increased tissue concentrations of tungsten and decreased tissue concentrations of molybdenum and tissue activities of xanthine dehydrogenase. 2. The rate of loss of large doses of tungsten from the liver occurred in an exponential manner with a half-life of 27 h. 3. When tungsten was administered to chicks fed on a semi-synthetic diet containing abnormally low concentrations of molybdenum, the activity of hepatic xanthine dehydrogenase was reduced to negligible levels. 4. The alterations in molybdenum metabolism resulting from the administration of large doses of tungsten to the chick appears to be the result of tungsten toxicity and not of molybdenum deficiency. 5. Deaths from tungsten toxicity occurred when tissue concentrations of tungsten were increased to approximately 25 micrograms/g liver. At this tissue tungstencon centration the activity of xanthine dehydrogenase was zero.

Animals↗
PubMed1980

The influence of sex, age and strain of chicken on liver biotin content.

Liver biotin concentrations were substantially lower in 2 to 4-week old broilers than in similarly aged layer-type chicks. Liver biotin concentrations plateauxed at 3 weeks of age. No consistent effect of sex was observed on liver biotin concentrations. The results are discussed in terms of susceptibility to biotin deficiency and fatty liver and kidney syndrome.

Aging↗
PubMed1979

The influence of vitamin A status on the response of chickens to aflatoxin B1 and changes in liver lipid metabolism associated with aflatoxicosis.

1 A series of experiments were conducted to investigate the effects of dietary retinol status on chickens ingesting aflatoxin B1. The effects of dietary supplementation with biotin and alpha-tocopherol were also examined. 2. Aflatoxin B1 levels greater than 1 mg/kg diet had a detrimental effect on 'liveability', body-weight gain, food intake and food conversion efficiency. When fed for more than 2 weeks aflatoxin increased relative liver weight and liver lipid concentration. These effects were less pronounced with avitaminotic A chickens. 3. A synergistic effect on hydropericardium development was observed between aflatoxin B1 and retinol. This effect was not observed when the dietary level of alpha-tocopherol was increased tenfold. 4. The specific activities of certain hepatic lipogenic and amino acid-metabolizing enzymes were influenced by aflatoxin ingestion. A reduction in lipogenic enzyme activity was observed before a reduction in the activities of amino acid-metabolizing enzymes. 5. Liver fatty acid composition was significantly influenced by aflatoxin B1. The extent of these changes was reduced by the inclusion of additional dietary biotin.

Aflatoxins↗
PubMed1979

Lactate administration and fatty liver and kidney syndrome development in biotin-deficient chicks.

Two experiments were carried out to determine whether administration of lactate to biotin-deficient chicks induced fatty liver and kidney syndrome (FLKS). 2. The results suggest that increased serum lactate concentrations are a consequence of the syndrome rather than a contributory factor in its incidence. 3. The increase in liver lipids of birds affected by FLKS was not associated with an increase in the specific activity of the hepatic lipogenic enzyme acetyl CoA carboxylase accept when birds developed FLKS spontaneously in experiment 2. 4. Some biotin-deficient chicks did not show physical symptoms of deficiency although mean liver biotin concentrations were low (0.31 microgram/g liver).

Acetyl-CoA Carboxylase↗
PubMed1978

The influence of elevated environmental temperature and nutrient intake on thyroid status and hepatic enzyme activities in immature male chicks.

1. Increases in hepatic ATP citrate lyase specific activity and in serum thyroxine levels were observed in immature chicks in response to either controlled food and water intakes at 22 degrees C, or an elevation in environmental temperature to 30 degrees C. Hepatic phosphofructokinase specific activity was reduced at the higher temperature. 2. Over a 4-week experimental period thyroid function and hepatic enzyme activities adapted to the controlled nutrient intake but not to the temperature stressor.

Animals↗
PubMed1978

Biotin deficiency and liver metabolism in relation to fatty liver and kidney syndrome.

Varying degrees of biotin deficiency were induced by adding freeze-dried, raw egg white to the diet of broiler chicks. Aspects of liver metabolism were studied with reference to fatty liver and kidney syndrome. Mortality was low with 11.8 g egg white/kg diet, or less, but with 17.7 g/kg or more, mortality was very high. High mortality was observed with less than 0.33 microgram biotin/g liver. Associated with low concentrations of liver biotin were substantial increases in liver weight and lipid content in starved birds. The increased liver lipid content was not observed in birds fed ad libitum. The increased liver lipid content in biotin-deficient, starved birds was not reflected in the specific activities of hepatic lipogenic enzymes or hepatic lipogenesis in vivo measured by the incorporation of tritium from 3H-labelled water into liver lipid. Biotin deficiency affected the specific activities of the biotin-requiring enzymes, pyruvate carboxylase and acetyl CoA carboxylase, differently; the latter was unaffected whereas the former decreased concomitantly with liver biotin concentration.

Animals↗