The genealogy of British Poultry Science.

The first issue of British Poultry Science was published in April 1960. In this paper the origin and development of the Journal and the organisations with which it has been associated are traced.

Glycemic index, cholecystokinin, satiety and disinhibition: is there an unappreciated paradox for overweight women?

BACKGROUND: The clinical utility of a low glycemic index (LGI) diet for appetite and food intake control is controversial. Complicating the issue are psychological and behavioral influences related to eating. OBJECTIVE: The aim of this study was to investigate the satiety and glycemic response to high GI (HGI) and LGI meals in overweight restrained (R, n=12) and unrestrained (UR, n=10) women. DESIGN AND MEASUREMENTS: In a randomized crossover study, subjective satiety, cholecystokinin (CCK), glucose, insulin, triacylglyceride (TG) and free fatty acids (FFAs) were measured at defined intervals for 8 h after the participants consumed HGI or LGI test meals. Test meals were matched for energy, energy density, macronutrient content and available carbohydrate, but differed by carbohydrate source; refined grain versus whole grain, respectively. RESULTS: The HGI meal resulted in greater satiety overall, suppressing hunger, desire to eat and prospective consumption compared with the LGI (P<0.01) meal. Plasma CCK was significantly elevated after the HGI meal compared with the LGI meal (P<0.001). Plasma glucose, insulin and TG were higher and FFAs were lower after the HGI meal compared with the LGI meal (P<0001). Dietary restraint did not significantly influence CCK (P=0.14) or subjective satiety (P>0.4); however, an interaction of restraint and disinhibition on CCK was apparent. CCK was blunted in R participants with higher disinhibition scores than UR or R participants with lower disinhibition scores (P<0.05). CONCLUSIONS: A LGI diet may not be suitable for optimal satiety and appetite control in overweight women. The relationship between cognitive influences of eating and biobehavioral outcomes requires further investigation.

Branch Width and Height Influence the Incorporation of Branches into Foraging Trails and Travel Speed in Leafcutter Ants Atta cephalotes (L.) (Hymenoptera: Formicidae).

Fallen branches are often incorporated into Atta cephalotes (L.) foraging trails to optimize leaf tissue transport rates and economize trail maintenance. Recent studies in lowlands show laden A. cephalotes travel faster across fallen branches than on ground, but more slowly ascending or descending a branch. The latter is likely because (1) it is difficult to travel up or downhill and (2) bottlenecks occur when branches are narrower than preceding trail. Hence, both branch height and width should determine whether branches decrease net travel times, but no study has evaluated it yet. Laden A. cephalotes were timed in relation to branch width and height across segments preceding, accessing, across, and departing a fallen branch in the highlands of Costa Rica. Ants traveled faster on branches than on cleared segments of trunk-trail, but accelerated when ascending or descending the branch-likely because of the absence of bottlenecks during the day in the highlands. Branch size did not affect ant speed in observed branches; the majority of which (22/24) varied from 11 to 120 mm in both height and width (average 66 mm in both cases). To determine whether ants exclude branches outside this range, ants were offered the choice between branches within this range and branches that were taller/wider than 120 mm. Ants strongly preferred the former. Our results indicate that A. cephalotes can adjust their speed to compensate for the difficulty of traveling on branch slopes. More generally, branch size should be considered when studying ant foraging efficiency.

Effects of repeated injections of glucagon on the stress response of the immature fowl.

Chicks aged two weeks were injected with either glucagon (50 micrograms/kg) or solvent daily for seven days. The two groups were then divided into two subggroups and received either glucagon or saline and their lipacid and glycaemic responses determined over a 60 minute period. Neither response was modified by the earlier treatment with glucagon. Birds that had received doses of glucagon were found to have increased concentrations of corticosterone in the blood plasma and a tendency to increased concentrations of free fatty acids. The increase in plasma corticosterone induces by a novel injection of glucagon, did not occur when the eighth injection was given.

Glucagon: a stress hormone in the domestic fowl.

Chicks were injected intraperitoneally with glucagon (50 micrograms/kg) once daily for five days, beginning on the first day after hatching. At seven days of age the chicks were weighed and tissues sampled. Growth rate was unaffected, relative adrenal weight was increased and there were significant increases in adrenal cholesterol stores. The birds were hypoglycaemic, hypercholesteraemic but had a decreased concentration of corticosterone in the plasma. The results are consistent with the hypothesis that glucagon is a stress hormone and that it is responsible for activating the hypothalamo-hypophyseal-adrenocortical axis.

Failure to induce stress reactions following vaccination against Marek's disease or Newcastle disease.

Chickens aged one or 21 days were given single injections of a vaccine against Marek's disease or Newcastle disease respectively, and monitored over a three week period for any signs of a stressor response. No consistent evidence of such a response was found. Some data on normal ontogenetic changes in various adrenal and plasma variables are also presented.

The effects of repeated injections of adrenaline on the response of the fowl to further alarm stimulation.

Chicks, aged two weeks, were injected with either adrenaline (300 microgram/kg) or saline daily for seven days. One day after the seventh injection it was found that the birds treated with adrenaline had become hypolipacidaemic and hypocholesteraemic and that there had been adrenal hypertrophy and an increase in the adrenal store of cholesterol. Plasma concentrations of glucose and corticosterone were within the normal range. The two groups (adrenaline- or saline-treated) were further subdivided each into two subgroups and were now injected with either adrenaline or saline, and their responses measured over a 120 min period. A significantly shorter period of hyperglycaemia was found in the birds pretreated with adrenaline and given a further injection of the hormone. These birds also showed an enhanced lipacidaemic response but the corticosterone response was not altered.

Stressor effects of handling on the immature fowl.

Chicks were handled for 5 min twice daily for five consecutive days per week over a three-week period. The control birds were not handled once they had been allotted to their brooders. The growth rate of the treated birds was significantly decreased. There was no adrenal hypertrophy; the concentration, but not the content, of adrenal cholesterol was significantly increased. Plasma glucose, FFA and cholesterol concentrations were similar in the groups at the end of the experiment. The lipolytic response of the handled birds to a further stimulus of handling was significantly greater than that of unhandled birds experiencing novel handling stimulus. There was also a significant decrease in the concentration of corticosterone in the plasma of the handled birds but not in the unhandled group. There was thus no evidence of habituation.

Stressor effects of adrenaline on the immature fowl.

Chicks were injected with L-adrenaline (500 microgram/kg) thrice weekly from hatching for one, two or three weeks. The growth rate of treated chicks was depressed, particularly in the first week. When four-week-old chicks were given nine injections of adrenaline over a three-week period, growth rate was also depressed but less severely. The greater sensitivity of the younger chicks is thought to result from an immature blood-brain barrier. Relative adrenal mass (mg/kg) was generally increased but adrenal cholesterol depletion occurred only in three-week-old birds treated with adrenaline throughout. Plasma glucose and cholesterole concentrations were within the normal range after three weeks of treatment but there was a significant hypolipacidaemia in the younger birds treated for two or three weeks.

The response of the immature fowl to multiple injections of adrenaline.

Chicks were injected, from one to 21 days of age, with either L-adrenaline (500 mug/kg) or the solvent three times a week. Birds treated with adrenaline showed an imparied growth rate. Relative (mg/kg0.75), but not absolute (mg) adrenal weight was significantly increased. No changes in adrenal cholesterol content or concentration were noted.

Physiological responses to stress with reference to the domestic fowl.

Environmental stress may effect the outcome of routine investigations as well as experimental procedures. This is illustrated by investigations in the domestic fowl.

Floor space allowances for the caged domestic fowl.

The maximal cross-sectional area, the length and the width of 48 pure bred hens weighing between 1 and 4 kg were determined using a photographic technique. It is shown that the typical (2.4 kg) bird occupies an area of 637 cm2 but that this value is much affected by the degree of feathering. The same bird is 21.3 cm wide and 41 cm long. Space allowances for caged birds are discussed in the light of these data.

Stress of transportation for broilers.

Transporting birds for two to four hours over distances of up to 224 km (140 miles) induced hyperlipacidaemia and hypoglycaemia while the concentration of plasma cholesterol decreased and then increased significantly. These responses were the same in summer and winter. Body temperature was not affected by the experimental conditions. There was a consistent increase in plasma corticosterone which was greater in winter than in summer.

An evaluation of adrenal mass and adrenal cholesterol as measures of adrenal activity.

1. The effects of twice daily injections of corticotrophin (1 IU/kg body weight) or restriction of food intake to 75% of normal on body mass, adrenal mass and adrenal cholesterol were determined on chicks from 1 to 21 d of age. 2. Only the birds subjected to restricted feeding showed a reduced growth rate. 3. There was no adrenal hypertrophy in birds receiving corticotrophin but in the restricted group there was transient hypertrophy at 2 weeks. 4. Depletion of adrenal cholesterol was noted only in the birds receiving corticotrophin. 5. It is concluded that neither depletion of cholesterol nor hypertrophy is an inevitable consequence of enhanced adrenal cortical activity.

Re-establishment of the stress response in Gallus domesticus after hatching.

Cold caused a hypercorticosteronaemia and hypothermia in the 2-day-old chick. Heat did not affect plasma corticosterone concentrations, despite the birds becoming hyperthermic. The 2-day-old chick has a lower resting concentration of corticosterone than the 1-day-old. The minimum effective dose of corticotrophin in stimulating a hypercorticosteronaemia was 0.5 IU/kg in the former, 1.0 IU/kg in the latter. It is concluded that stress non-responsiveness persists for about 48 hr after hatching and that it is due to a temporary inhibition of hypothalamic function.

Breeding for disease resistance--the prospective role of genetic manipulation.

Economic considerations have meant that selection for resistance to disease has taken second place to that for productivity traits. Recent developments in genetic manipulation suggest that this may not be necessary in the future because it has become feasible to insert resistance genes into the genome of the fowl without compromising existing productivity traits. This review considers aspects of the genetic manipulation of disease resistance of the fowl, methods available for inserting genes and the identification of genes for insertion. It is concluded that of the technical strategies for inserting genes currently being developed those utilising defective, non-replicating retroviruses are the most promising. Studies to identify genes associated with resistance to disease are only now beginning. Although there has been some research into generalised immunological resistance to disease the results have been disappointing, and it seems likely that the use of specific resistance genes relating to each pathogen will be necessary. In particular the use of complementary or antisense genes to inhibit viral infections seems particularly promising.