Effects of Resource Allocation on Behavioural Strategies: A Comparison of Red Junglefowl (Gallus gallus) and Two Domesticated Breeds of Poultry

Three different breeds of poultry, representing different degrees of domestication, were observed in semi-natural conditions in order to study differences in foraging behaviour, activity levels and social behaviours which could be caused by correlated responses to selection for increased production. The breeds used were: (i) red junglefowl ( Gallus gallus ); (ii) Swedish bantam, which is a domestic breed that has not undergone selection for production traits; and (iii) Hy-Line, a White leghorn laying hybrid, selected mainly for food conversion efficiency. The birds were offered ad libitum food simultaneously from sites where the food was freely available and from sites where the birds had to search and scratch for food which was mixed with wood-shavings. The behaviour was observed three times per day (48 min/d), 3 d per week in eight groups (four birds per group) of each breed between 7 and 18 wks of age. Junglefowl and bantam obtained a significantly higher proportion of their food from the site that required effort. The opposite case was true for the Hy-Line. Overall, bantams performed significantly more foraging behaviour than Hy-Lines. The Hy-Line breed was more inactive and less involved in social interactions than the junglefowl and the bantam. The results support the idea that selection for high production results in modified behavioural strategies. Behaviours that are of high energetic cost, such as extensive foraging and social interactions, were of lower in frequency in the laying hens compared to junglefowl and bantam, allowing the laying hens to save energy that can be reallocated to production traits.     

Chicken domestication: from archeology to genomics

Current knowledge on chicken domestication is reviewed on the basis of archaeological, historical and molecular data. Several domestication centres have been identified in South and South-East Asia. Gallus?gallus is the major ancestor species, but Gallus?sonneratii has also contributed to the genetic make-up of the domestic chicken. Genetic diversity is now distributed among traditional populations, standardized breeds and highly selected lines. Knowing the genome sequence has accelerated the identification of causal mutations determining major morphological differences between wild Gallus and domestic breeds. Comparative genome resequencing between Gallus and domestic chickens has identified 21 selective sweeps, one involving a non-synonymous mutation in the TSHR gene, which functional consequences remain to be explored. The resequencing approach could also identify candidate genes responsible of quantitative traits loci (QTL) effects in selected lines. Genomics is opening new ways to understand major switches that took place during domestication and subsequent selection.     

Analysis of genetic diversity and phylogenetic relationships among red jungle fowls and Chinese domestic fowls

Genetic diversity and phylogenetic relationships among 568 individuals of two red jungle fowl subspe- cies (Gallus gallus spadiceus in China and Gallus gallus gallus in Thailand) and 14 Chinese domestic chicken breeds were evaluated with 29 microstaellite loci, the genetic variability within population and genetic differentiation among population were estimated, and then genetic diversity and phylogenetic relationships were analyzed among red jungle fowls and Chinese domestic fowls. A total of 286 alleles were detected in 16 population with 29 microsatellite markers and the average number of the alleles observed in 29 microsatellite loci was 9.86±6.36. The overall expected heterozygosity of all population was 0.6708±0.0251, and the number of population deviated from Hardy-Weinberg equilibrium per locus ranged from 0 to 7. In the whole population, the average of genetic differentiation among population, measured as FST value, was 16.7% (P<0.001), and all loci contributed significantly (P<0.001) to this differentiation. It can also be seen that the deficit of heterozygotes was very high (0.015) (P<0.01). Reynolds' distance values varied between 0.036 (Xiaoshan chicken-Luyuan chicken pair) and 0.330 (G. gallus gallus-Gushi chicken pair). The Nm value ranged from 0.533 (between G. gallus gallus and Gushi chicken) to 5.833 (between Xiaoshan chicken and Luyuan chicken). An unrooted consensus tree was constructed using the neighbour-joining method and the Reynolds' genetic distance. The heavy-body sized chicken breeds, Luyuan chicken, Xiaoshan chicken, Beijing Fatty chicken, Henan Game chicken, Huainan Partridge and Langshan chicken formed one branch, and it had a close genetic relationship between Xiaoshan chicken-Luyuan chicken pair and Chahua chicken-Tibetan chicken pair. Chahua chicken and Tibetan chicken had closer genetic relationship with these two subspecies of red jungle fowl than other domestic chicken breeds. G. gallus spadiceus showed closer phylogenetic relationship with Chinese domestic chicken breeds than G. gallus gallus. All 29 microstaellite loci in this study showed high levels of polymorphism and significant genetic differentiation was observed among two subspecies of red jungle fowl and 14 Chinese domestic chicken breeds. The evolutional dendrogram is as follows: evolutional breeds→primitive breeds (Chahua chicken and Tibetan)→red jungle fowl in China (G. gallus spadiceus)→red jungle fowl in Thailand (G. gallus gallus). The results supported the theory that the domestic fowls might originate from different subspecies of red jungle fowl and Chinese domestic fowls had independent origin.     

The origin and genetic diversity of Chinese native chicken breeds

The first 539 bases of mitochondrial DNA D-loop region of six Chinese native chicken breeds (Gallus gallus domesticus) were sequenced and compared to those of the red junglefowl (Gallus gallus), the gray junglefowl (Gallus sonneratii), the green junglefowl (Gallus varius) and Lafayette's junglefowl (Gallus lafayettei) reported in GenBank, and the phylogenetic trees for the chickens were constructed based on the D-loop sequences. The results showed that the four species of the genus Gallus had great differences among each other, the G. g. domesticus was closest to the red junglefowl in Thailand and its adjacent regions, suggesting the Chinese domestic fowl probably originated from the red junglefowl in these regions. The two subs pecies of Thailand, G. g. gallus and G. g. spadiceus, should belong to one subspecies because of their resemblance. In the case of native breeds, there existed a great difference between the egg breeds and general purpose breeds, which suggested different maternal origins of the two types.     

云南地方鸡种的遗传多样性及其与中国家鸡起源的关系

云南地方鸡种在生境、形态外貌、细胞遗传和血液蛋白等方面均表现出多样性,但mtDNA的遗传变异单一。云南地方鸡种有其独特的基因类型,由于所处的特殊地理位置和生态条件差异,形成了与我国其它鸡种相对独立的鸡种。从血液蛋白、细胞遗传和mtDNA等方面进一步证明红色原鸡为家鸡的祖先。云南可能是中国家鸡的起源中心之一。     

Eimeria tenella: Host Specificity in Gallinaceous Birds

SYNOPSIS. Eight species representing 8 genera of gallinaceous birds were used: Alectoris graeca; Colinus virginianus; Coturnix coturnix; Gallus gallus; Meleagris gallopavo; Numidia meleagris; Pavo cristatus; Phasianus colchicus. Three-week-old birds were dosed with sporulated oocysts of Eimeria tenella Beltsville strain. At 4, 24, 48, 72, 96, 120, 144, and 168 hr after inoculation, 1-3 infected birds and uninoculated controls of each species were killed by cardiac exsanguination. Pieces of intestines were fixed and examined for stages of E. tenella as stained paraffin sections or indirect fluorescent antibody preparations. Oocyst counts were made in droppings collected for the first 6 days of the patent period. Sporozoites were found in the lamina propria of some birds of 5 species at 4 hr postinoculation, but no stages were found thereafter except in the breeds of G. gallus and A. graeca. At 144 and 168 hr postinoculation, a few macrogametes were found in the ceca of 2 A. graeca , but no oocysts were found in the feces. No statistical difference was found between the number of oocysts produced/bird in the breeds of G. gallus examined. It is evident from these observations that E. tenella did not complete its life cycle in several close phylogenetic relatives of G. gallus , even though in other studies this parasite was found to complete its life cycle in cell cultures derived from the same birds.     

Species-typical and Individually Distinctive Acoustic Features of Crow Calls of Red Jungle Fowl

Crow calls of red jungle fowl (Gallus gallus) were analyzed for the purposes of (a) determining the extent of commonality and variability of acoustic features within and between individual roosters, and (b) characterizing the modal crow call of this species. Comparisons were made between crow calls of jungle fowl and those of domestic fowl to assess the extent to which domestication has affected these motor patterns.     

Eimeria tenella: host specificity in gallinaceous birds.

Eight species representing 8 genera of gallinaceous birds were used: Alectoris graeca; Colinus virginianus; Coturnix coturnix; Gallus gallus; Meleagris gallopavo; Numidia meleagris; Pavo cristatus; Phasianus colchicus. Three week-old birds were dosed with sporulated oocysts of Eimeria tenella Beltsville strain. At 4, 24, 48, 72, 96, 120 and 144, and 168 hr after inoculation, 1-3 infected birds and uninoculated controls of each species were killed by cardiac exsanguination. Pieces of intestines were fixed and examined for stages of E. tenella as stained paraffin sections or indirect fluorescent antibody preparations. Oocyst counts were made in droppings collected for the first 6 days of the patent period. Sporozoites were found in the lamina propria of some birds of 5 species at 4 hr postinoculation, but no stages were found thereafter except in the breeds of G. gallus and A. gracea. At 144 and 168 hr postinoculation, a few macrogametes were found in the ceca of 2 A. gracea, but no oocysts were found in the feces. No statistical difference was found between the number of oocysts produced/bird in the breeds of G. gallus examined. It is evident from these observations the E. tenella did not complete its life cycle in several close phylogenetic relatives of G. gallus, even though in other studies this parasite was found to complete its life cycle in cell cultures derived from the same birds.     

家鹅线粒体tRNAthr与tRNApro序列与结构分析

本研究采用PCR和DNA测序技术测定了6个中国家鹅品种和2个欧洲鹅品种25个个体线粒体DNA tRNApro（69bp）和tRNAthr（68bp）基因的完整序列,通过对家鹅线粒体基因组的研究,首次报道了家鹅线粒体tRNApro和tRNAthr基因的结构,对鸿雁家鹅、灰雁家鹅、白额雁（Anser albifrons,序列号为AF363031）种间的tRNApro和tRNAthr基因的二级结构及序列的变异特征进行了分析,并通过家鸡（Gallus gallus domesticus,序列号为NC001323）与鸿雁家鹅间tRNApro和tRNAthr基因二级结构的比较,初步进行了鸡形目与雁形目两个目间tRNApro和tRNAthr基因二级结构及序列变异的分析。结果表明：家鹅tRNApro和tRNAthr基因均可折叠成标准的三叶草形二级结构; 2个tRNA基因三叶草结构的氨基酸臂、反密码子环在鸿雁、灰雁和白额雁种间以及鸡形目与雁形目两个目间没有发生变异,具有高度的保守性。本研究的结果将为进一步探讨家鹅线粒体DNA tRNApro和tRNAthr基因序列与结构、功能的关系奠定基础。所测定的基因序列已登录国际GenBank数据库,序列号为AY427800～AY427805和AY427812～AY427814。     

Age and hunting success in the brown pelican: influences of skill and patch choice on foraging efficiency

Summary Age-related differences in the foraging efficiency of piscivorous birds may be the results of differences in foraging skill, patch usage, or both. Brown pelicans were observed while foraging around a small Caribbean island. Areas where the birds fed were subdivided into small, homogeneous subunits (patches), and the bird's foraging success and patch use were noted and analyzed using multivariate techniques. Adult birds were found to be better at capturing prey under all conditions than were juveniles, but the differences were small in some patches. The density of prey and the birds' foraging success influenced the foraging efforts of adult and juvenile pelicans to similar degrees. Both age groups utilized local enhancement in their foraging, but such behavior augmented the foraging success only of juvenile birds. Both age groups often fed in patches where their foraging success was quite low. Such behaviour was much more costly for juvenile than for adult pelicans.     

A variant in the restriction endonuclease cleavage pattern of mitochondrial DNA in the domestic fowl, Gallus gallus domesticus

The cleavage patterns of mitochondrial DNAs (mtDNAs) were investigated from 15 lines of domestic fowls, Gallus gallus domesticus, using 11 restriction endonucleases. The cleavage patterns with 10 restriction endonucleases were identical in all the lines. A variant was found in a line of White Leghorn in the pattern with MspI digestions. Cleavage patterns of the red jungle fowl, Gallus gallus gallus, were identical to the common patterns shown by the 14 lines of domestic fowls.     

A variant in the restriction endonuclease cleavage pattern of mitochondrial DNA in the domestic fowl, Gallus gallus domesticus

Summary. The cleavage patterns of mitochondrial DNAs (mtDNAs) were investigated from 15 lines of domestic fowls, Gallus gallus domesticus . using 11 restriction endonucleases. The cleavage patterns with 10 restriction endonucleases were identical in all the lines. A variant was found in a line of White Leghorn in the pattern with Mspl digestions. Cleavage patterns of the red jungle fowl, Gallus gallus gallus , were identical to the common patterns shown by the 14 lines of domestic fowls.     

Agonistic behaviour,responses to a novel object and some aspects of maintenance behaviour in feral-strain and domestic chickens

Feral-strain fowl, bred from birds captured on North-West Island (24°S, 150°E), were compared with domestic chickens hatched and raised under similar conditions. Aspects of behaviour considered included agonistic behaviour and responses to unfamiliar environments and objects. There were many similarities between the feral and domestic fowl in behaviour, but there were also many differences between the strains.Feral cockerels showed higher levels of agonistic behaviour than domestic cockerels, under some conditions. There were differences between young feral and Leghorn-cross chickens in the “freezing” response to handling and placement in an unfamiliar cage, with the feral chickens responding more rapidly.Feral cockerels showed a greater initial avoidance of a novel object than did Black Australorp bantam cockerels, but after a short interval they spent more time near the novel object than the bantams.These results are discussed in relation to selection pressures under conditions of domestication, and on North-West Island.     

Chicken domestication: an updated perspective based on mitochondrial genomes

Domestic chickens (Gallus gallus domesticus) fulfill various roles ranging from food and entertainment to religion and ornamentation. To survey its genetic diversity and trace the history of domestication, we investigated a total of 4938 mitochondrial DNA (mtDNA) fragments including 2843 previously published and 2095 de novo units from 2044 domestic chickens and 51 red junglefowl (Gallus gallus). To obtain the highest possible level of molecular resolution, 50 representative samples were further selected for total mtDNA genome sequencing. A fine-gained mtDNA phylogeny was investigated by defining haplogroups A–I and W–Z. Common haplogroups A–G were shared by domestic chickens and red junglefowl. Rare haplogroups H–I and W–Z were specific to domestic chickens and red junglefowl, respectively. We re-evaluated the global mtDNA profiles of chickens. The geographic distribution for each of major haplogroups was examined. Our results revealed new complexities of history in chicken domestication because in the phylogeny lineages from the red junglefowl were mingled with those of the domestic chickens. Several local domestication events in South Asia, Southwest China and Southeast Asia were identified. The assessment of chicken mtDNA data also facilitated our understanding about the Austronesian settlement in the Pacific.     

The distribution of endogenous chicken retrovirus sequences in the DNA of galliform birds does not coincide with avian phylogenetic relationships.

The chicken is a domesticated form of Red Jungle-fowl (Gallus gallus), which belongs to the Pheasant family (Phasianidae) within the order Galliformes. Domestic chickens carry the genome of the endogenous retrovirus RAV-O as DNA sequences integrated into host chromosomes transmitted through the germ line. We have examined the presence and distribution of RAV-O-related sequences in the DNA of Red Junglefowl and other closely related species of Junglefowl, as well as more distantly related Pheasants and Quail. DNA sequences homologous to RAV-O were analyzed by molecular hybridization in liquid and after electrophoresis of restriction endonuclease fragments. The presence of RAV-O-related sequences in avian DNA does not correlate with phylogenetic relationships. Under stringent conditions of hybridization in liquid, DNA sequences homologous to RAV-O cDNA were detected at high levels (greater than 80% homology( only in the genomes of the domestic chicken and its phylogenetic ancestor, the Red Junglefowl (Gallus gallus). The DNA of two other species of Gallus (G. sonnerati, Sonnerat's Junglefowl and G. varius, Green Junglefowl), of Ring-necked Pheasant and of Japanese Quail contained sequences with less than 10% homology to RAV-O cDNA. Under conditions permitting mismatching, however, Ring-necked Pheasant DNA hybridized up to 50% of the RAV-O cDNA, and Quail DNA 24%, whereas the extent of hybridization to Sonnerat's and Green Junglefowl DNA was not markedly increased. Analysis of restriction enzyme digests revealed several distinct fragments of DNA hybridizing to chick retrovirus cDNA in both Red Junglefowl and domestic chicken, and multiple fragments in DNA from two species of Phasianus. No fragments with sequences related to chicken retroviruses were found, however, in digests of DNA prepared from Sonnerat's, Ceylonese and Green Junglefowl, from two other Pheasant genera (Chrysolophus and Lophura), or from one Quail genus (Coturnix). Thus the DNA of three Junglefowl species closely related to Gallus gallus lacked RAV-O sequences while the DNA of more distantly related Phasianus species showed significant homology. These results show that RAV-O-related sequences have not diverged together with the normal host genes during the evolution of the Phasianidae. Although RAV-O sequences are endogenous in all domestic chickens and Red Junglefowl studied thus far, it appears that the RAV-O genome has been introduced relatively recently into the germ line of Gallus gallus, following speciation but before domestication, and independently of the related sequences found in members of the genus Phasianus.     

Phylogenetic distribution of the novel avian endogenous provirus family EAV-0

A new family of related endogenous proviruses, existing at 50 to 100 copies per haploid genome and distinguishable by remarkably short long terminal repeats, has been described for domestic chickens (Gallus gallus subsp domesticus). In this communication, by using Southern blot analysis and probes derived from both internal viral sequences and locus-specific, cellular flanking sequences, we studied the genetic distribution of this family of moderately repetitive avian endogenous retroviruses within the genomes of four Gallus species. Eight inbred lines of domestic chickens, the evolutionary progenitor to the domestic chicken (red jungle fowl), and two more distantly related species (grey and green jungle fowl) were studied. All Gallus species harbored this class of elements, although the different lines of domestic chickens and different species of jungle fowl bore distinguishable complements of the proviral loci. Jungle fowl appeared to have fewer copies than domestic chickens. For three randomly isolated proviral loci, domestic chickens (G. gallus subsp. domesticus) and red jungle fowl (G. gallus subsp. gallus) showed only a proviral state, whereas the most primitive and divergent of the jungle fowl, the green jungle fowl (G. varius), consistently demonstrated only preintegration states or disparate alleles. The presence of this family in all Gallus species and of related sequences in other genera suggests that a primordial founding integration event occurred prior to the evolutionary separation of Gallus species and possibly related genera. Additionally, at least one proviral locus has been acquired subsequent to speciation, indicating that this family was actively infectious after the primary founding event. This conserved, repetitive proviral family appears to represent the vestigial remnant of an avian retrovirus class related to and evolutionarily more ancient than the Rous-associated virus-0 family of avian endogenous retroviruses.     

Domestic chickens defy Rensch's rule: sexual size dimorphism in chicken breeds

Sexual size dimorphism (SSD), i.e. the difference in sizes of males and females, is a key evolutionary feature that is related to ecology, behaviour and life histories of organisms. Although the basic patterns of SSD are well documented for several major taxa, the processes generating SSD are poorly understood. Domesticated animals offer excellent opportunities for testing predictions of functional explanations of SSD theory because domestic stocks were often selected by humans for particular desirable traits. Here, we analyse SSD in 139 breeds of domestic chickens Gallus gallus domesticus and compare them to their wild relatives (pheasants, partridges and grouse; Phasianidae, 53 species). SSD was male-biased in all chicken breeds, because males were 21.5 ± 0.55% (mean ± SE) heavier than females. The extent of SSD did not differ among breed categories (cock fighting, ornamental and breeds selected for egg and meat production). SSD of chicken breeds was not different from wild pheasants and allies (23.5 ± 3.43%), although the wild ancestor of chickens, the red jungle fowl G. gallus, had more extreme SSD (male 68.8% heavier) than any domesticated breed. Male mass and female mass exhibited positive allometry among pheasants and allies, consistently with the Rensch's rule reported from various taxa. However, body mass scaled isometrically across chicken breeds. The latter results suggest that sex-specific selection on males vs. females is necessary to generate positive allometry, i.e. the Rensch's rule, in wild populations.     

中国红原鸡和泰国红原鸡遗传多样性分析

利用29个微卫星DNA标记对来自中国的红原鸡Gallus gallus spadiceus亚种和来自泰国的红原鸡Gallus gallus gallus亚种进行遗传多样性分析, 评估亚种内的遗传变异和亚种间的遗传分化, 结果表明: 共检测到168个等位基因, 每个位点的等位基因数从2到13不等, 所有位点平均的期望杂合度和PIC值分别为0.5780和0.53。中国和泰国红原鸡29个微卫星位点平均有效等位基因数分别为3.79和4.79, 平均基因杂合度为0.5379和0.6385, 两个红原鸡亚种均表现出较高的群体杂合度和丰富的遗传多样性。群体分化系数为19.4%(P<0.01), 两个红原鸡亚种间的Reynolds’遗传距离和Nm值分别为0.157和1.040。由此可见, Gallus gallus spadiceus亚种和Gallus gallus gallus亚种群体具有不同的群体遗传结构, 群体之间存在明显的遗传分化, 并不能将其认定为是同一亚种, 这也为中国家鸡具有独立的起源提供了一定的佐证。     

Is there social transmission of feather pecking in groups of laying hen chicks?

Feather pecking is an abnormal behaviour where laying hens peck the feathers of conspecifics, damaging the plumage or even injuring the skin. If it occurs in a flock, more and more birds show it within a short period of time. A possible mechanism is social transmission. Several studies have shown that laying hen chicks, Gallus gallus domesticus, are able to modify their own behaviour when observing the behaviour of other chicks, for example, when feeding and foraging. As there is good experimental evidence that feather pecking originates from foraging behaviour, we hypothesized that feather pecking could also be socially transmitted. To test this, we reared 16 groups of 30 chicks. After week 4, the birds were regrouped into 16 groups of 20 chicks into each of which we introduced either five chicks that showed high frequencies of feather pecking or, as controls, five chicks that had not developed feather pecking. We then determined the feather-pecking rate and the frequency of foraging, dustbathing, feeding, drinking, preening, moving, standing and resting of all birds in a group. Data from the introduced birds were analysed separately and excluded from the group data. Chicks in groups with introduced feather-pecking chicks had a significantly higher feather-pecking rate than chicks in the control groups. In addition, birds in groups with introduced feather peckers showed significantly lower foraging frequencies than those in the control groups, although the housing conditions were identical and there were no differences in either the number or the quality of the stimuli relevant to foraging behaviour. The study therefore suggests that feather pecking is socially transmitted in groups of laying hen chicks. Copyright 2000 The Association for the Study of Animal Behaviour.     

Individual differences in foraging site fidelity are not related to time-activity budgets in Herring Gulls

Many populations consist of individuals that differ consistently in their foraging behaviour through resource or foraging site selection. Foraging site fidelity has been reported in several seabird species as a common phenomenon. It is considered especially beneficial in spatially and/or temporally predictable environments in which fidelity is thought to increase energy intake, thereby affecting time-energy budgets. However, the consequences for activity and energy budget have not been adequately tested. In this paper, we studied the consequences of fine-scale foraging site fidelity in adult Herring Gulls Larus argentatus in a highly predictable foraging environment with distinct foraging patches. We measured their time-activity budgets using GPS tracking and tri-axial acceleration measurements, which also made it possible to estimate energy expenditure. Individual variation in foraging site fidelity was high, some individuals spending most of their time on a single foraging patch and others spending the same amount of time in up to 21 patches. While time and activity budgets differed between individuals, we found no clear relationship with foraging site fidelity. We did find a relationship between the size of the birds and the level of site fidelity; faithful birds tend to have a larger body size. Although differences in foraging time and habitat use between individuals could play a role in the results of the current study, short-term consequences of variation in foraging site fidelity within a population remain elusive, even when focusing on individuals with a similar foraging specialization (Blue Mussels Mytilus edulis). Studying individuals over multiple years and under varying environmental conditions may provide better insight into the consequences and plasticity of foraging site fidelity.