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At least 847 records · Page 47Linked to original sources
PubMed1989

Selection experiment for increased egg production under 23 H and 24 H light-dark cycles in the domestic fowl.

A selection experiment was conducted for increased rate of lay under 23-h (23 HS line) and 24-h (24 HS line) light-dark cycles over 5 generations. In generation 5, rate of lay was higher in the 23 HS line than in the 24 HS line, and the proportion of hens with mean intra-sequence intervals of less than 24 h in the 23 HS line increased to 88% in the generation 5 from 15% in the base generation. The realised heritability for rate of lay was 0.25 plus/minus 0.04 in the 23 HS line and 0.15 plus/minus 0.05 in the 24 HS line. Egg weight and shell weight decreased in both lines, and the decrease in the proportion of shell was larger in the 23 HS line than in the 24 line. It is suggested that a regimen of 23 h light and dark may be an effective environment for selection to improve the laying performance of a population approaching a plateau for egg production.

Animals↗
PubMed1989

Changes in the concentration and composition of biliary and serum bile acids in the young domestic fowl.

1. Concentrations of biliary and serum bile acids, their molecular compositions and serum cholesterol concentrations were determined in chicks at 2, 3, 4 and 6 weeks of age. 2. The concentration of biliary bile acid was maximal at 3 to 4 weeks, decreasing by 6 weeks of age. 3. The serum concentration of bile acid was maximal at three weeks of age. 4. Serum total cholesterol increased from two weeks and was maximal at 6 weeks of age. 5. Chenodeoxycholic acid was the predominant biliary unconjugated bile acid. 6. Tauro-chenodeoxycholic acid and tauro-cholic acid were the dominant molecular species of biliary and serum conjugated bile acid.

Age Factors↗
PubMed1989

Ultrastructural alterations of the thyroid follicular cells in domestic fowls following neonatal olfactory bulbectomy.

1. In order to investigate if ultrastructural alterations of thyroid follicular cells are induced by removal of the olfactory bulb at hatching, chicks were olfactory bulbectomised within 24 h after hatching and the thyroid follicular cells were examined at 5 months of age by electron microscopy. 2. Olfactory bulbectomised chickens showed a well-developed Golgi area, a highly-developed rough endoplasmic reticulum, many mitochondria and a paucity of secretory granules and lysosomes in thyroid follicular cells. 3. These hypertrophic ultrastructural changes in follicular cells of operated birds indicated that the thyroids glands were stimulated by neonatal olfactory bulbectomy. 4. This finding may suggest an establishment of the olfactory bulbothyroid glandular system during the early days of life in the chicken.

Animals↗
PubMed1989

Broken bones in domestic fowl: handling and processing damage in end-of-lay battery hens.

1. 3115 end-of-lay battery hens and carcases were sampled at set points in the sequence of events that occurred between depopulation of the battery cages at the layer farms and the end of the evisceration line in two processing plants. Live birds were killed in a convulsion-free manner and carcases were dissected to determine the incidence of broken bones. 2. Of the live battery birds 29% had broken bones by the time they reached the waterbath stunner, with on average 0.5 broken bones per bird. Removing birds from the battery cages and hanging them on the slaughter line were identified as causes of broken bones. 3. By the time birds left the end of the eviscerating line, 98% of carcases had broken bones, with on average 6 broken bones each. The stunning, plucking and eviscerating processes caused most of this damage. In particular, stunning broke the furculum, coracoid and scapula, plucking broke the ischium, pubis and ribs, and evisceration damaged the ischium and pubis.

Abattoirs↗
PubMed1990

Plasma concentrations of arginine vasotocin and mesotocin following pentobarbital anaesthesia and carotid cannulation in domestic fowl.

1. Plasma concentrations of arginine vasotocin (AVT) and mesotocin (MT), arterial pH and pCO2, body temperature, respiratory rate, heart rate, mean arterial blood pressure, packed cell volume and plasma osmolality were monitored in birds for 28 h following anaesthesia and carotid cannulation. 2. Plasma MT concentration decreased after 6 h of surgical recovery but there were no differences between 6 and 28 h of recovery. 3. In contrast, plasma AVT concentration was raised only after 27 h, but no differences were observed between 3 and 28 h of recovery. 4. Anaesthesia and/or carotid cannulation apparently suppressed AVT and enhanced MT release, but no significant change in either hormone was observed after 6 h of surgical recovery under the conditions specified in this study.

Anesthesia↗
PubMed1990

Test for linkage between the eumelanin dilution blue (B1), the extended black (E) allele at the E-locus and the linked pea comb (P) and eumelanin extension (M1) genes in the domestic fowl.

1. A mating was made between a Blue Andalusian bantam male and a pea comb striped necked bantam female to produce a quadruple heterozygote of the linked pea comb (P) and eumelanin extension (Ml) genes and of the eunmelanin dilution blue (Bl) gene and the extended black (E) allele at the E-locus. 2. Two pea comb blue females so produced were mated to a single comb striped necked bantam male, thus providing a backcross to the quadruple recessive. 3. Bl segregated independently with each of the other three genes whilst 25 crossovers occurred amongst the 55 progeny assessed for linkage between P and Ml, confirming loose linkage between P and Ml which had previously been shown to be approximately 46 units. Linkage of 0.3% had been previously reported (Crawford, 1986) between P and a "melanotic" gene isolated from a segregating gene pool. Evidence is presented to demonstrate that two different "melanotic" genes were being considered, thus explaining the apparently contradictory reports. Charcoal (cha) is suggested for the recessive gene linked with P by 0.3%. 4. Thirty-four crossovers occurred among the 97 progeny between P and E suggesting linkage of approximately 35 units. A further mating was made from among segregants in the backcross which confirmed P-E linkage with 17 crossovers in 55 gametes. Combining the tests produced a linkage value of approximately 34 units.

Alleles↗
PubMed1990

Reproductive senescence in domestic fowl: effects on egg production, sequence length and inter-sequence pause length.

1. Age-related changes in egg production, oviposition sequence length and inter-sequence pause length were studied by analysis of oviposition records of 50 individually-caged broiler breeders from 24 to 62 weeks of age. 2. The 44 surviving hens exhibited a production profile characteristic of broiler breeders (184 eggs per hen), with a peak mean sequence length of 19 eggs at 32 weeks of age. Inter-sequence pause length was maximum (1.6 d) at 54 weeks of age. Overall, the hens averaged 48 sequences, with a mean sequence length of 4.1 d. 3. Most hens had a single characteristically long sequence about the time of peak egg production (average: 24.3 d). The term 'prime' is suggested to denote this sequence. 4. Sorting the hens into groups on the basis of total egg output (upper and lower 50% and upper and lower 25%) indicated that high producing hens (upper 50% and 25%) had a very long prime sequence early in lay, and had few inter-sequence pauses of greater than 1 d duration. The converse was true for low producers (lower 50% and 25%). 5. The length of the prime sequence may be a good indicator of reproductive efficiency of hens later in life.

Aging↗
PubMed1992

Further studies on the inheritance of the marbled chickdown phenotype of the domestic fowl.

1. An investigation was conducted among the progeny from crosses between Birchen Modern Game and Silver Sebright bantams into the inheritance of the marbled chickdown phenotype of the latter. 2. The marbled chickdown phenotype has been shown to depend upon homozygocity of both the birchen allele ER at the E-locus and the eumelanin restrictor gene Db. However, all stock used to establish this result were also homozygous for the linked eumelanin intensifier melanotic Ml and the pattern gene Pg, therefore yielding no information on the roles of Ml or Pg in the marbled chickdown phenotype. 3. Examination of the F2 generation both of chickdown and of adult plumage demonstrated the marbled chickdown to be homozygous ER (Db-Pg) with Ml dosage having an effect on adult plumage.

Animals↗
PubMed1992

Variation in egg yolk cholesterol concentration between and within breeds of the domestic fowl.

1. The pattern of variation for egg yolk cholesterol concentration between 5 commercial egg layer lines and a cross of Gallus domesticus is described. 2. Yolk cholesterol concentration in the cross was lower than in the lines, and 6.7% lower than the midparent value. 3. It is proposed that the reduced yolk cholesterol concentration of the cross may be a consequence of heterosis, although sex-linkage and/or maternal effects cannot be discounted. 4. The difference between the cross and parental lines is consistent with a physiological relationship between yolk cholesterol concentration and rate of egg production, but not between yolk cholesterol concentration and yolk weight.

Animals↗
PubMed1992

Occurrence of intraportally-infused urea-15N in the urine of domestic fowl.

1. Measurements were made in situ to determine the occurrence of intraportally infused urea-15N in ureteral urine of the fowl. 2. Of the total amount of infused urea-15N, 15% was excreted intact into the urine (90% of urinary total 15N) whereas 9% remained unchanged in the blood (78% of blood non-protein-15N). 3. The proportions of non-protein-15N in the blood, liver and kidney were 12, 3 and 1%, respectively of the infused 15N. Protein-15N was 3% of that infused in blood and much less in liver and kidney. 4. About 1% of the infused 15N was observed in the urinary uric acid, and 3% of the infused 15N in non-protein N, other than urea, ammonia and glutamine amide N, of blood and liver. 5. No appreciable amounts of 15N were present in ammonia and glutamine amide N of blood, liver or kidney and in uric acid of liver or kidney. 6. The caecal contents contained about 1% of the infused 15N with 15% of this as ammonia-15N. 7. It is concluded that intraportal urea is mostly excreted unchanged into ureteral urine of the fowl.

Animals↗
PubMed1993

Further studies of linkage and mappings of the loci of genes in group 3 on chromosome 1 of the domestic fowl.

1. Evidence is presented to confirm the placing of the extended black E-locus in linkage Group 3 on chromosome 1, E being linked with peacomb P by 43 map units. P has been shown to be linked with dark-brown columbian Db and sleepy-eye se by 32 and 45 map units, respectively, se being independent of E. 2. Evidence is also presented to demonstrate independence of E and Db; hence, Db and se have their loci on the same side of P, the gene order being E-P-Db-se, thus contradicting published mappings which place P between Db and se. 3. An investigation into the deductive relationships on which published mappings are based led to the conclusion that insufficient evidence existed for the inclusion of the sub-group comprising blood group Ea-P, naked neck Na, silky feathering h and flightless Fl as part of Group 3. 4. Furthermore, it appears only 4 genes in Group 3 have actually had their loci mapped; blue egg O, P, the eumelanin extension charcoal cha and the feather growth restrictor tardy t. 5. No evidence appears to have been presented to establish on which arm of chromosome 1 any of the other genes in Group 3 have their loci. A revised map of chromosome 1 and a schematic arrangement to demonstrate the relative linkage distances of the loci of the unmapped genes in Group 3 are presented and explained.

Animals↗
PubMed1994

Divergent selection for delayed-type wattle reaction of domestic fowls to BCG antigen.

1. Two-way selection for delayed-type hypersensitivity wattle reaction (DWR) competence to BCG antigen was carried out over 4 generations, using a flock of White Leghorn chickens. DWR was measured by intradermal injection of BCG into the wattle of chickens. 2. Selection for DWR was effective. The generation means of average selection differential, selection response and realized heritability were 1.15 mm, 0.77 mm and 0.70 respectively. Correlated responses were found in body weight, egg weight and hatchability. In all of these traits, the L line (selected for low wattle reaction) showed higher values than the H line (high reaction). 3. Specific trends in gene frequencies were observed at the major histocompatibility B and alkaline phosphatase Akp loci. 4. Significant line differences were found in graft-versus-host reaction competence and Marek's disease resistance. In both characters, the L line was higher than the H line. No line differences were found in phytohaemagglutinin response, phagocytic activity or immune responses.

Animals↗
PubMed1994

Variation in plasma cholesterol concentration over time in the domestic fowl.

1. Variations in the concentration of plasma cholesterol available to the developing oocyte over a three week period in Gallus domesticus are described. 2. There are small changes in concentration between weeks for individual birds, but no changes between consecutive days within weeks or times within days. 3. It is recommended that future attempts to assess the relationship between variation in blood and yolk cholesterol concentrations estimate blood cholesterol concentration from two samples taken a week apart.

Analysis of Variance↗
PubMed1996

Lighting and mortality rates in domestic fowl.

1. Data from intermittent and conventional lighting trials were analysed to investigate the effect of daily illumination upon mortality during the laying period and in 49-d-old broilers. 2. Liveability in laying hens was improved by the use of intermittent lighting: the degree of improvement was proportional to the reduction in daily illumination achieved by the intermittent programme. 3. The reduction in mortality with intermittent lighting in laying hens was not the result of intermittent lighting per se. Intermittent regimens which did not reduce daily illumination did not reduce mortality. 4. Mortality in both conventionally-lit laying hens and 49-d old-broiler chickens increased with photoperiod.

Animals↗
PubMed1996

Ontogenetic development of proline intestinal transport in the domestic fowl.

1. The proline disappearance from the jejunal and ileal lumen of chickens aged from 1 day to 15 weeks were studied using a perfusion method "in vivo". 2. A decrease in proline transport was observed from younger to older animals. The 2 intestinal segments showed different behaviours, the 1-day and 1-week-old animals showed the same value in the jejunum, whereas in the ileum a progressive decrease in proline transport was observed from the first week of life. 3. The differences observed in the 2 segments could be attributed to the different rates of growth of the jejunum and ileum with age; the jejunum showed a peak of growth in the second week of life whereas the ileum showed a peak of growth in the first week. Proline transport in the jejunum decreased until the fifth week and remained constant thereafter.

Aging↗
PubMed1996

Chocolate: a sex-linked recessive plumage colour mutant of the domestic fowl.

1. A mating between Black Orpington bantams produced, in addition to blacks, a single female in which the black colouration was replaced by dark chocolate. 2. A mating of the chocolate-coloured female with a black male, F2 and backcross matings demonstrated that the chocolate phenotype is caused by a recessive sex-linked gene to which I assign the symbol *CHOC. 3. A mating of "chocolates' inter se yielded all chocolate offspring.

Animals↗