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PubMed1980

The effect of an injection of corticotrophin on plasma concentrations of corticosterone, growth hormone and prolactin in two strains of domestic fowl.

1. Three-week-old Light Sussex (LS) and Rhode Island Red (RIR) chicks were injected with long-acting corticotrophin (ACTH: 30 IU/kg) and the plasma concentrations of corticosterone, growth hormone (GH) and prolactin were determined over a 6-h period. Plasma concentrations of corticosterone and growth hormone were also measured after an injection of corticosterone (500 microgram/kg). 2. The resting plasma concentration of corticosterone in LS was less than that in RIR birds. The increase elicited by ACTH was smaller in LS but, since it was maintained for longer, the plasma corticosterone response was at least 18% larger than that in RIR birds. 3. Plasma GH concentration was decreased after an injection of ACTH in both strains but the decrease lasted longer in the LS chicks. 4. Plasma prolactin concentration was unaffected by ACTH. 5. After intra-abdominal injection of corticosterone, plasma GH concentration was depressed in both strains. It is concluded that ACTH-induced depression of plasma GH and growth is mediated by corticosterone.

Adrenocorticotropic Hormone↗
PubMed1980

Caecal growth in the domestic fowl following surgical manipulation.

1. Some effects of removing increasing proportions of the left caecum on the remaining caecal tissue and on the right caecum were studied in young chicks during a period of 35 d. The chicks were 22 d old when the operations were carried out. 2. No differences were detected between the gains in weight of the control and experimental groups of birds. 3. A marked negative linear relationship was observed between the dry weight of the amount of caecal tissue removed when the birds were 22 d old and weight of the left caecum at the end of the experiment. 4. The average growth rate of the left caecum (g dry tissue/week) was found to be dependent on the estimated weight of caecal tissue remaining after surgery. 5. No evidence was obtained to indicate that the growth of the right caecum responded to the removal of the left caecal tissue. 6. The morphology and histology of the operated caeca were found to be similar to the equivalent regions of the unoperated caeca. Surgical interference was not followed by any major changes in mucosal architecture. 7. In birds which had experienced unilateral caecectomy, the discharge of caecal faeces usually stopped for about 2 d. When caecal defaecation was resumed, the pattern of defaecation appeared to be the same as that observed in sham-operated birds with both caeca intact.

Animals↗
PubMed1980

Food intake and oviposition by domestic fowl under symmetric skeleton photoperiods.

1. Under a symmetric skeleton photoperiod of 2 h light, 10 h dark, 2 h light and 10 h dark (2L : 10D : 2L : 10D), most ovipositions occurred in the first 10-h dark period with an important mode during the first hour of darkness. 2. With a gradual increase of the first dark period (the period of activity), the ovipositions become increasingly spread throughout the 24-h cycle; a complete phase shift for the timing of oviposition was observed with the programme 2 h light, 11 h 15 min dark, 2 h light and 8 h 45 min dark (2L : 11.15D : 2L : 8.45D). 3. With the photoperiod 2L : 10D : 2L : 10D, the servicing of the birds during either 2-h light period, and the withdrawal of calcium source during either the second 2-h light period or during the first 10-h dark and second 2-h light periods did not change the timing of ovipositions.

Animals↗
PubMed1983

The effects of dietary intake and of dietary concentration of copper sulphate on the laying domestic fowl: effects on laying performance and tissue mineral contents.

Sixty white hybrid (Shaver 288) laying hens were subjected to three main dietary regimens for 5 d: ad libitum feeding of control and CuSO4-supplemented diets, force-feeding these same diets to the same intake as that of the ad libitum control diet and pair-feeding the control CuSO4-free diet to intakes equivalent to those of supplemented diets. Final body weight of the force-fed birds was significantly greater than of the other groups. Egg number and weight were significantly reduced as food intake decreased. Liver weight per unit body weight was significantly increased and oviduct and ovary weights/kg body weight were significantly reduced by force-feeding. As food intake decreased kidney and gizzard weights per unit body weight were significantly increased. The concentrations and total contents of Cu and Zn in liver were significantly increased in the ad libitum and force-fed groups. Force-feeding CuSO4-supplemented diets, which eliminated difference in food intake, confirmed that CuSO4 per se affected tissue weights and mineral concentrations as distinct from effects due to the reduced food intake associated with increasing dietary CuSO4.

Animals↗
PubMed1983

The effects of dietary intake and of dietary concentration of copper sulphate on the laying domestic fowl: effects on some aspects of lipid, carbohydrate and amino acid metabolism.

These investigations were carried out to determine whether the effects of feeding CuSO4-supplemented diets on metabolism in the laying hen were due directly to the dietary CuSO4 content or indirectly to the effects of CuSO4 on food consumption. In experiment 1, 144 hens were given CuSO4-supplemented diets ad libitum for 48 d. Food consumption decreased as the dietary CuSO4 content increased and this was associated with decreases in blood plasma lipid, 17 beta-oestradiol and liver lipid concentrations and hepatic lipogenic enzyme activities. In experiment 2, 60 laying hens were subjected to three dietary regimens in an attempt to differentiate between the effects of reduced food consumption and dietary CuSO4 per se. Control and CuSO4-supplemented diets were fed ad libitum, or the CuSO4-containing diets were force-fed to the same intake as the ad libitum control diet, or the control diet was pair-fed to the same intakes as the CuSO4-supplemented diets. Liver lipid concentrations were significantly decreased in the ad libitum and pair-fed groups at the lowest intake. Plasma 17 beta-oestradiol concentration was decreased in ad libitum and force-fed birds given diets with 1,000 mg added Cu/kg. Lipogenic enzyme activities were reduced in the ad libitum and pair-fed groups and increased in the force-fed birds. The results indicate that CuSO4 per se directly affected circulating 17 beta-oestradiol, and hence reproductive physiology, and that the quantity of food consumed influenced the rate of hepatic lipogenesis.

Amino Acids↗
PubMed1983

Pharmacological disruption of broodiness in White Rock domestic fowls.

The administration of bromocriptine (CB154) to broody hens (Gallus domesticus) impaired resumption of lay. Resumption of lay was stimulated in broody birds treated with clomiphene citrate (an anti-oestrogen) alone or following CB154 administration. The increased oviposition rate following a single intramuscular injection (21 mg) of clomiphene was long lasting, persisting for at least 16 weeks after treatment. Treatment of broody hens with clomiphene consistently improved (by 4%) the hatchability of the fertile eggs subsequently laid.

Animals↗
PubMed1984

Changes in the plasma concentration of immunoreactive arginine vasotocin during oviposition in the domestic fowl.

The plasma concentrations of immunoreactive arginine vasotocin (AVT) were measured during oviposition and shortly before ovulation of the first egg (Cl) of a clutch. Immunoreactive AVT was determined on bentonite extracts of 0.5 ml plasma samples using the method of Rosenbloom and Fisher (1974). The R-70 antiserum used to measure AVT cross reacted with arginine vasopressin (AVP), however the fowl pituitary does not synthesise AVP. Over a period of 10 to 90 min before oviposition the plasma AVT concentration was about 20 pg/ml; during oviposition it increased four-fold. Measurements made at frequent intervals showed that plasma AVT concentration increased 5 to 6 min before oviposition, reached a peak during oviposition itself and decreased rapidly in the following 5 to 6 min. The surge in plasma AVT occurred on average 48 min before Cl ovulation.

Animals↗
PubMed1985

Effect of the eumelanin restrictor Db on plumage pattern phenotypes of the domestic fowl.

An investigation was conducted among the progeny from crosses between Gold-Pencilled Hamburgh and Partridge Wyandotte bantams into the relationship between two plumage pattern phenotypes, pencilling and autosomal barring, both of which are arrangements of eumelanin expressed on a background of phaeomelanic pigmentation. A eumelanin restricting gene Db had previously been shown to be responsible for the barred phenotype when acting in conjunction with a pattern arranging gene Ab. The pencilled phenotype had been presumed to be caused by the presence of a pencilling gene Pg. The F2 generation consisted entirely of three phenotypes: barred, pencilled and intermediary, with presumed genotypes DB/Db, db+/db+ and Db/db+ respectively, indicating that Ab and Pg are one and the same gene, for which I propose the retention of the symbol Pg. The gene action of Db when homozygous is therefore to prevent curvature, so changing pencilling into barring.

Animals↗
PubMed1985

Effects of air velocity on convective and radiant heat transfer from domestic fowls at environmental temperatures of 20 degrees and 30 degrees C.

The effects of air movement upon sensible heat loss from individual birds at ambient temperatures of 20 degrees and 30 degrees C were determined by partitional calorimetry using a newly developed wind tunnel calorimeter. The relationship between area specific convective heat loss (W/m2) and air velocity (in the range 0.3 to 1.05 m/s) was described by y = 56.5 + 16.9 log x at an air temperature of 20 degrees C, but at 30 degrees C convective heat loss increased linearly with air speed (y = 11.8 + 40.1 x). At 20 degrees C sensible heat exchange (W/m2) was related to air velocity by y = 70.6 exp (0.099 x) and by y = 41.4 + 25.9 x at 30 degrees C, the proportional increase with air speed being greater at the higher temperature. The differences in the effects of air movement on convective cooling and sensible heat loss at 20 degrees and 30 degrees C reflect the thermoregulatory responses of the birds, induced by the thermal demands of the environment.

Air Movements↗
PubMed1986

Gordon memorial lecture. The biologists' debt to the domestic fowl.

Although it is highly desirable to reduce the need for experiments with animals, in vitro methods cannot entirely supplant them. Observations made in simple systems must be checked in a live subject if they are to be relevant to man or other higher animals. Young growing chicks are very susceptible to vitamin deficiencies. Biological assays in chicks have been used to check the validity of chemical and microbiological methods of measuring vitamins in foods. Experiments with chicks and chick embryos deprived of vitamin B12 have served to predict the likely clinical effects of analogues of the vitamin. The discovery of the growth-promoting properties of dietary antibiotics stimulated research into the influence of the gut microflora on its host. Studies in germ-free and gnotobiotic chicks have implicated Streptococcus faecium as one of the organisms responsible for the growth depression reversed by antibiotics. In general the growth of conventional chicks given adequate diets is slightly less good than that of their germ-free counterparts, although small beneficial effects of the microflora have been observed in special circumstances. The most important function of the indigenous microflora appears to be as a barrier against invasion by pathogens. To sustain this protective barrier may incur a small cost to the host in terms of dietary energy and other nutrients.

Animals↗
PubMed1987

Test for linkage between the eumelanin restrictor (Db) and the eumelanin extension (Ml) genes in the domestic fowl.

A mating was made between a Gold-Pencilled Hamburgh bantam male and a double-laced bantam female to produce a double heterozygote of the linked eumelanin restrictor (Db) and eumelanin extension (Ml) genes. A male so produced was mated to a pen of Partridge Wyandotte bantam females, thus providing a backcross to the double recessive. Three crossovers occurred among the 31 female progeny suggesting linkage of approximately 10 units between Db and Ml. The pattern gene Pg has previously been shown to be linked with both Db and Ml by approximately 17 and 10 units respectively. The locus of Ml appears therefore to lie between the loci of Db and Pg.

Animals↗
PubMed1987

Relative positions of the loci of the peacomb (P), eumelanin restrictor (Db), eumelanin extension (Ml) and plumage pattern (Pg) genes of the domestic fowl.

A single comb Partridge Wyandotte bantam male was mated with two Indian Game bantam females to produce a double heterozygote of the linked eumelanin extension (Ml) and pea comb (P) genes. Four females so produced were mated with their sire to provide a backcross to the double recessive. Forty crossovers occurred among the 86 progeny suggesting linkage of approximately 46 units between Ml and P. The eumelanin restrictor gene (Db) had previously been shown to be linked with P, Ml and Pg by approximately 28, 10 and 17 units respectively and, furthermore, the locus of Ml had been shown to lie between the loci of Db and Pg. The locus of Db appears therefore to lie between the loci of P and Ml and hence the relative positions of the loci of the 4 genes is P, Db, Ml, Pg.

Animals↗
PubMed1987

Withdrawal of zinc oxide-containing diets from mature, female domestic fowl: effects on laying performance and the weights of selected tissues.

1. Two hundred and sixteen laying hens of two strains were given diets containing ZnO to provide 0, 0.5, 0.75, 1.00, 1.25, 1.50, 2.00, 3.00 or 4.00 g added Zn/kg. These diets were given ad libitum for 5 consecutive 28-d periods. All hens subsequently received the control diet with no added ZnO for 5 weeks. 2. Four hens from each treatment were killed 0, 1 and 5 weeks after substitution of the ZnO-supplemented diets by the control diet. 3. The adverse effects of the ZnO-containing diets on body weight, food intake, egg production, pancreas, gizzard, oviduct and ovary weights/kg body weight were reversed by removal of the ZnO from the diets. 4. Five weeks after withdrawal egg production of the group which had received the diet with the highest concentration of added ZnO was only 50% of that of the control birds. 5. The beneficial effect of the added ZnO on internal egg quality was not maintained after withdrawal of the ZnO-containing diets.

Animals↗
PubMed1987

Withdrawal of zinc oxide-containing diets from mature, female domestic fowl: effects on selected tissue mineral contents.

1. Two hundred and sixteen laying hens of two strains were given diets containing ZnO to provide 0, 0.5, 0.75, 1.00, 1.25, 1.50, 2.00, 3.00 or 4.00 g added Zn/kg. These diets were offered ad libitum for 5 consecutive 28-d periods. All hens were subsequently offered the control diet with no added ZnO for 5 weeks. 2. Four hens from each treatment were killed 0, 1 and 5 weeks after substitution of the ZnO-supplemented diets by the control diet. 3. Dietary addition of ZnO significantly increased liver, kidneys, pancreas and gizzard Zn contents but this effect was rapidly reversed on removal of the ZnO-containing diets. 4. Hepatic and renal Fe contents were significantly depressed by dietary ZnO but after substitution of these diets by the control diet the values were comparable to that of the controls. 5. Liver Cu content declined significantly as dietary ZnO concentration increased but there was a return towards normal after ZnO withdrawal. Renal, pancreatic and gizzard Cu contents showed quadratic responses to added ZnO. 6. After ZnO withdrawal for 5 weeks, pancreas Cu contents declined linearly, whereas renal and gizzard Cu values were similar for all treatments. 7. Overall the long-term feeding of ZnO-supplemented diets followed by a period of withdrawal of the ZnO supplement had no detrimental effects on tissue mineral contents.

Animals↗
PubMed1987

Evidence that the mottled (mo) and pied (pi) plumage genes of the domestic fowl are identical.

1. An investigation was conducted among the progeny from crosses between Exchequer Leghorn and Ancona bantams into the relationship between two plumage phenotypes, pied and mottled, both of which are arrangements of non-pigmentation expressed on a background of eumelanin. 2. Both the pied and mottled phenotypes had previously shown to be caused by recessive genes, denoted pi and mo respectively. 3. The progeny consisted entirely of intermediaries between the two parental phenotypes, indicating that pi and mo are one and the same gene for which I retain the symbol mo.

Animals↗
PubMed1988

Strain differences in the number and size of glomeruli in domestic fowl.

1. An investigation was made into strain differences and the effect of the type of drinker on the number and size of glomeruli of Single Comb White Leghorn pullets. 2. The Dekalb XL strain had more glomeruli per kidney and per g of kidney than the Hyline W-36. The glomeruli of the Dekalb XL were smaller in circumference. There were no significant differences in the absolute or relative weights of the kidney. 3. The type of drinker, bell or trigger-cups, had no effect on the body weight or those kidney variables studied.

Animals↗
PubMed1988

Energy expenditure and physical activity in domestic fowl kept on standard and interrupted lighting patterns.

1. The energy expenditure (H) and physical activity of laying hens were measured under lighting regimes of 14L:10D (standard), 2L:10D:2L:10D (interrupted) and (15 X (13 min L:47 min D]: 9D (fragmented). 2. Neither of the intermittent regimes produced a significant change in total daily energy expenditure, although large alterations occurred in the distribution of H between the lighting phases. The absence of change in total H resulted from the combined effects of greater H in the light in the intermittent regimes, greater H in darkness during the interrupted day than at night and slightly greater H at night in the intermittent regimes. 3. Physical activity count, like H, was redistributed over time but, unlike H, was also significantly reduced in total; changes in the energy cost of unit activity, however, were such that no reduction occurred in the total amount of H attributable to activity. 4. In the standard groups, 90% of total activity costs were incurred in the light; in the fragmented-day and interrupted-day groups, respectively, 7% and 55% of total activity costs were incurred in the light periods and 85% and 30% in daytime darkness. 5. In terms of both H and activity, there was clear differentiation between night darkness and subjective-day darkness. 6. Even when the energy cost of activity was excluded, significant differences remained between H at night, H in the light and H in daytime darkness.

Animals↗