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Biomedical subjects

D J Farrell

Publications and source records attributed to D J Farrell.

At least 109 records · Page 6Linked to original sources
PubMed1976

Energy and nitrogen metabolism of diseased chickens: interaction of Ascaridia galli infestation and vitamin A status.

1. Effects of Ascaridia galli infection on the energy and nitrogen (N) metabolism were studied on groups of 5 cross-bred cockerels aged about 5 weeks and given a diet deficient or adequate in vitamin A at two levels of feeding in respiration chambers. 2. Metabolisability of dietary energy was 67% and N retention 33% in infected chickens compared with 71 and 41% respectively, in uninfected chickens. 3. Maintenance energy requirement of vitamin A-deficient birds was 882 kJ/kgW d compared with 998 kJ/kgW d for normal birds. N balance of the deficient chickens was also less when compared at the same energy balance. Infection did not affect maintenance energy requirement nor N balance. 4. Starvation heat production of infected chickens (619 kJ/kgW d) was higher than that of uninfected controls (586 kJ/kgW d). When infection treatments were combined, vitamin A-adequate chickens had a higher heat production (615 kJ/kg d) than the vitamin A-deficient (580 kJ/kgW d). Endogenous N excretion (mg/gW) was less in vitamin A-deficient than in adequate, starved birds. 5. Deficient chickens had undetectable liver reserves of vitamin A and only very low plasma concentrations. There was a difference in the length of larvae (17 d after infection) associated with vitamin A status, and with level of feeding.

Animal Feed↗
PubMed1976

Energy and nitrogen metabolism of diseased chickens: aflatoxicosis.

1. New Hampshire chicks were fed on diets containing 0 (control), 0-7 (A), or 1-1 (B) ppm of aflatoxin B1. In two trials 1-d-old chicks were offered ad libitum the three diets for 14 d. The gaseous exchange of five chickens from each group was measured for 3 or 4 d, the same diets being fed, at 2, 3, 4 and 5 weeks of age in two series of experiments. The controls were fed at the lower intake of the two other groups. Following each series of experiments at the various ages, birds were starved for 24 h and their heat production was re-measured over the next 24 h. 2. Mortality was highest and growth and food conversion poorest where the diet with the highest aflatoxin concentration was fed. Mortality was confined to the first 2 weeks. 3. Performance of birds in the chambers was improved in the second series due to differences in food intake. It also improved with age suggesting some resistance to the toxin. 4. Mean respiratory quotient was 0-97 for fed chickens on diet B. This was significantly different from 0-92 for the two other groups. Similarly, during starvation the RQ was 0-76 compared with 0-73. 5. birds fed on diet B generally grew better, retained more nitrogen and had a better energy balance in the respiration chambers than the other two groups. Metabolisability of dietary energy was less (68.5%) for all groups at 2 to 3 weeks than when older (70%) but availability of ME was the same (71%) for all groups. 6. Heat production (kJ/kg0-75) of starved birds on diet B was significantly lower than the other two groups, while endogenous nitrogen excretion was higher. 7. Water consumption (ml/g food and g/100 g body weight) was greatest for birds on diet B. 8. Although aflatoxin in the diet substantially reduced intake there was no indication that at these reduced levels of intake, nitrogen or energy metabolism were measurably impaired.

Aflatoxins↗
PubMed1976

Flow rates of components in digesta of pigs prepared with re-entrant cannulas in the proximal duodenum and terminal ileum, and fed semipurified, hard wheat, and soft wheat diets.

Four pigs prepared with re-entrant cannulas in the proximal duodenum and terminal ileum were used to study flow rates of total digesta, insoluble dry matter, nitrogen, and amino acids entering and leaving the small intestine. The pigs received a semipurified diet, a hard wheat diet, or a soft wheat diet. These were approximately isonitrogenous. A higher rate of passage of digesta through the proximal duodenum and terminal ileum were measured in pigs receiving the hard wheat diet. Peak flow of digesta at the duodenum of all pigs occurred at 1 h post feeding. Peak flow of digesta at the ileum occurred at 9 h post feeding on the soft wheat diet, but somewhat earlier on the hard wheat and semipurified diet. More nitrogen and essential amino acids flowed in the solid fraction of duodenal digesta during the first 2 h post feeding for the wheat diets and 4 h post feeding for the semipurified diet. It was concluded that flow rate of most nutrients from the stomach and through the small intestine of pigs is modified by the composition and texture of the food ingested. It is postulated that efficiency of mixing of digesta with digestive secretions in the stomach is a major factor influencing rate of flow.

Amino Acids, Essential↗
PubMed1975

A comparison of the energy metabolism of two breeds of hens and their cross using respiration calorimetry.

1. The maintenance energy requirement of the Black Australorp, White Leghorn and Black Australorp times White Leghorn hen was 911, 765 and 885 kJ/d respectively and availability of metabolisable energy of the diet was 79, 84 and 92%. 2. Heat production, after 30 h of starvation, was 311, 395 and 387 kJ/kg W0-75/d for the Australorp, Leghorn and crossbred, respectively. 3. It was calculated that availability of metabolisable energy was 51% for protein and 96% for fat retention. 4. Water consumption was significantly higher for the Black Australorp at the mean level of food intake for all hens, and increased more rapidly per unit intake than was observed for the other two breeds.

Animal Feed↗
PubMed1975

Effects of different temperature regimens on body composition and carry-over effects on energy metabolism of growing chickens.

Groups of cross-bred cockerels, four weeks of age, were held at 5 different temperature treatments (5-34 degrees C.) for 30 days, and were then killed at about 8 weeks of age. Food consumption and growth rate declined with increased temperature, and there was a significant increase in fat, and a decrease in water content of the carcasses. Calorimetric measurements at 20 degrees C. of pairs of starved birds after 7, 15 and 25 days exposure to different temperature regimens showed a decline in heat production (kJ./kg.W or W0.73) with increased temperature and with duration of prior treatment (kj./kg.W). Effects of previous temperature exposure were apparently not entirely dispelled when similar measurements were made on pairs of birds that had been on the treatments for at least 25 days and then held for 4 days at 20 degrees C. before measurements were commenced. Calorimetric measurements made at 20 degrees C. on fed pairs of birds during a 3-day period following at least 25 days of temperature treatment showed several carry-over effects. Metabolizable energy concentration of the diet and nitrogen retention increased, and heat increment decreased, as a result of prior exposure of the birds to increasing temperature.

Acclimatization↗