Interaction between acquired preferences and developing predispositions during imprinting

Preferences of domestic chicks were studied either at approximately 2 h or approximately 24 h after exposure to a red box or a stuffed jungle fowl. Preferences of the chicks were measured in a simultaneous choice test involving these two stimuli. When tested at about 2 h, chicks preferred the object to which they had previously been exposed. Chicks tested at about 24 h showed a significantly greater preference for the jungle folw than those tested at about 2 h, regardless of the training stimulus. Birds that had been placed in a running wheel and exposed to diffuse light also showed an increasing preference for the fowl over time when tested in the same manner. These results may be accounted for in terms of an interaction between two processes, a developing predisposition for the fowl on the one hand and a preference acquired through learning on the other.     

Development of filial preferences in dark-reared chicks

When given a simultaneous choice preference test 24h after being allowed a period of time in running wheels, dark-reared domestic chicks, Gallus gallus domesticus, will approach a stuffed jungle fowl in preference to a red box. The present study was designed to determine which aspects of the stuffed fowl were critical for the emergence of this preference. In all experiments the preferences of dark-reared chicks were studied in a test involving the simultaneous presentation of an intact stuffed jungle fowl and a second, test object. In experiment 1 this object was a ‘complex’ red box, in experiments 2.1 and 2.2 disarticulated stuffed fowl, and in experiment 2.3 the ‘scrambled’ skin of a jungle fowl. The results of these experiments suggested that particular arrangements or configurations of features, and not outline or textural complexity alone, are important for the emergence of the predisposition. Further support for this hypothesis was obtained in experiment 2.4 in which the intact fowl was compared to a test object containing such configurations of features. The result of experiment 3 suggested that the configuration of features associated with the head and neck region are particularly important, while the results of experiments 4 and 5, in which the test objects were a stuffed gadwall duck and a stuffed polecat, respectively, established that the configuration of features esential for the predisposition is not species specific.     

Reversibility revisited: Stimulus-dependent stability of filial preference in the chick

The reversibility of filial preferences was studied in domestic chicks, Gallus gallus domesticus, using an artificial as well as a more naturalistic imprinting stimulus. Day-old chicks were exposed for 2 h to either a rotating stuffed jungle fowl or a rotating red box. Two hours later their preferences were tested in a simultaneous choice test (test I), involving the box and the fowl. The next day, the chicks were trained and tested (test II) as before, except box-trained chicks were now exposed to the fowl and vice versa. In three different experimental groups, the relative attractiveness of the two stimuli (as measured in test I) was varied by altering the light intensity of the red box. In the chicks trained with the box and subsequently exposed to the fowl, there was a significant decrease in mean preference for the box from test I to test II. In contrast, the preference of the chicks trained with the stuffed fowl were not affected by subsequent exposure to the red box. This differential reversibility was also found when, in test I, the preference for the box was significantly higher than the preference for the fowl. These results support a model of the formation of filial preference as an interaction between acquired preference and a developing predisposition for a particular class of stimuli.     

Parent-offspring recognition in bank swallows (Riparia riparia): II. Development and acoustic basis

In study 1, bank swallow (Riparia riparia) chicks were exchanged with like-aged chicks from other broods. Parents accepted chicks that were transferred into their nests at age 15 days or younger; rejection began to occur at 16 to 17 days. In study 2, chicks' vocalizations were recorded in the burrow. We found that an immature begging call given by young chicks is replaced by a ‘signature’ call at 15 to 17 days of age. An acoustic analysis suggested that these calls are individually distinctive. Study 3 was a playback experiment designed to test whether the chicks' signature calls are a sufficient cue for parental recognition. We found that parents would approach a speaker broadcasting the calls of their chicks in preference to one simultaneously broadcasting the calls of alien chicks. The pattern of results suggests that parental recognition is based on the chicks' signature calls and that development of recognition is dependent on the development of the call.     

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。     

Chicks' preferences for familiar and novel conspicuous objects after different periods of exposure

When length of exposure to a flashing rotating light was varied, the subsequent preferences of day-old chicks for the familiar object first increased as a function of exposure, then decreased and finally increased once again. The temporary reversal of the trend for an increasingly restricted preference for the familiar object occurred after 30 min of exposure. The reversal was not critically dependent on the time from exposure to testing. It is attributed to the chicks' preferences for slight novelty which were superimposed on their growing preference for familiarity.     

Nest Defense by Red Jungle Fowl (Gallus gallus spadiceus) Hens: The Roles of Renesting Potential,Parental Experience and Brood Reproductive Value

Reproductive-effort theory predicts that parents of any given age should expend more parental effort (1) as their residual reproductive value declines, and (2) as the reproductive value of offspring increases. An observational and experimental study of nest defense by captive red jungle fowl hens was used to examine these two predictions. Both young and old individuals significantly increased defense of the second nest compared to the first nest within a season; this pattern occurred for the defense of both eggs and chicks. Old hens showed significantly greater defense of both eggs and chicks in each of the nests than did young hens. Both young and old hens were significantly more defensive of chicks than eggs in each of two clutches of a season. Hens also reduced their nest defense significantly at the end of a two to three-day period after their chicks were replaced with eggs, and increased their nest defense after eggs were exchanged for chicks. Hens given four chicks showed more vigorous defense than hens given two chicks. When the brood size of hens with four chicks was reduced to one chick, the hens responded by exhibiting less vigorous nest defense. These patterns of nest defense in jungle fowl were not confounded by parental experience of hens, or differences in offspring quality that are related to time of breeding, maternal age, sire genetic quality or vulnerability of offspring to weather.     

Cryopreservation of Indian red jungle fowl (Gallus gallus murghi) semen with polyvinylpyrrolidone

The Indian red jungle fowl is a sub-species of the genus Gallus native to South Asia; facing high risk of extinction in its native habitat. During cryopreservation, permeable cryoprotectants like glycerol are usually employed and we previously showed encouraging results with 20% glycerol. Because bird spermatozoa contain very little intracellular water, the possibility of replacing an internal cryoprotectant by an external one is opened. In the present study, we tested the replacement of internal cryoprotectant glycerol by the external cryoprotectant Polyvinylpyrrolidone (PVP). PVP is a non-permeable cryoprotectant and keeps the sperm in glassy state both in cooling and warming stages without making ice crystallization within the sperm cell. We evaluated the effect of various levels of polyvinylpyrrolidone (PVP) on Indian red jungle fowl semen quality and fertility outcomes. The qualifying semen ejaculates collected from eight mature cocks were pooled, divided into five aliquots, diluted (37 °C) with red fowl semen extender having PVP [0% (control) 4% (w/v), 6% (w/v), 8% (w/v) and 10% (w/v)]. Diluted semen was cryopreserved and stored in liquid nitrogen. The whole experiment was repeated/replicated for five times independently. Sperm motility, plasma membrane integrity, viability and acrosome integrity were recorded highest (P < 0.05) with 6% PVP at post-dilution, cooling, equilibration and freeze-thawing. Higher (P < 0.05) no. of fertile eggs, fertility, no. of hatched chicks, percent hatch and hatchability was recorded with 6% PVP compared to control. It is concluded that 6% PVP maintained better post-taw quality and fertility of Indian red jungle fowl spermatozoa than glycerol and can be used in routine practice avoiding the contraceptive effects of glycerol.     

家鸡和原鸡的线粒体DNA多态性比较

本文运用１１种限制性内切酶分析了家鸡（茶花鸡、尼西鸡、大理漾濞黄鸡）和原鸡共１０只个体的线粒体ＤＮＡ限制性片段长度多态性（ＲＦＬＰ）,平均每个个检测到的片段为４０条左右。但仅发现３种变异的限制性片制性格局,即ＳｔｕＩ－Ｂ,Ｅｃａ－Ｉ－ｂ和ＲＩ－Ｂ．其中ＳｔｕＩ－Ｂ和ＳｃａＩ－Ｂ为首次报道,而且均为原鸡所物有,ＥｃｏＲＩ－Ｂ则为大理漾濞黄鸡所特有。茶花鸡和尼西鸡拥有完全相同的限制性格局。经过计算,原     

家鸡腺苷琥珀酸裂解酶基因多态性与肌苷酸含量的关联及其与红原鸡的亲缘关系

根据腺苷琥珀酸裂解酶(adenylosuccinate lyase, ADSL)基因外显子2的序列设计引物, 用PCR-SSCP的方法对隐性白羽鸡、丝羽乌骨鸡、白耳鸡、藏鸡以及红色原鸡两个亚种进行了单核苷酸多态性分析, 并检测到了多态性, 表现为3种基因型, 对两种纯合子进行直接测序, 结果发现3484位碱基处发生C→T突变。对3种基因型的肌肉肌苷酸含量的最小二乘分析结果显示TT型(突变型)个体的肌肉肌苷酸含量极显著地高于CT型、显著地高于CC型个体, CT型个体也稍高于CC型, 但差异不显著, 初步推测该位点可能与肌肉肌苷酸含量有关。根据该多态位点的基因频率, 基于Nei氏的遗传距离运用NJ聚类法构建系统发生树, 进行家鸡与原鸡的亲缘关系分析, 结果发现, 丝羽乌骨鸡与白耳鸡的亲缘关系最近, 藏鸡和中国红原鸡亚种的亲缘关系也较近, 中国地方家鸡品种与中国红原鸡亚种的亲缘关系较近,而与泰国红色原鸡的亲缘关系较远,隐性白羽鸡与原鸡亲缘关系最远, 初步得出中国家鸡有自己独自的血缘来源的结论。     

Familiarity interferes with filial imprinting

The present study was performed to investigate whether and how pre-exposure to an object affects subsequent filial imprinting to that object. In Experiment 1 junglefowl chicks (Gallus gallus spadiceus) were first exposed to either a red object alone (control group), or a red and a yellow object simultaneously (experimental group; phase 1). Subsequently, all chicks were exposed to the yellow object in the presence of a black and blue one (phase 2). At the end of phase 1, most experimental chicks had developed a preference for the red object over the yellow one. At the end of phase 2, preferences of experimental chicks were shifted away from the yellow object towards the novel black and blue object, relative to preferences of control chicks. This shows that pre-exposure may interfere with imprinting. Experiment 2 revealed that when control chicks were tested with the yellow object at the end of phase 1, filial responses were as strong as in experimental chicks. This shows that the yellow object had not acquired control over filial behaviour during phase 1, and also that the relatively impaired imprinting on that object in phase 2 was not due to reduced generalization from the red object. One possible explanation why pre-exposure may interfere with imprinting is that familiarity alters the level of attention attracted by an object, a mechanism suggested to underlie ‘latent inhibition’ in conditioning.     

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.     

METABOLIC AND DIGESTIVE RESPONSES TO ARTIFICIAL SELECTION IN CHICKENS

Compared to ancestral wild jungle fowl, domestic broiler chickens have been consciously selected for large body size, relatively large pectoral muscles, rapid growth, and high feed efficiency. Hence intraspecific comparisons of these two strains could help identify consequences of unconscious artificial selection, trade-offs in energy allocation, and factors limiting energy budgets. We therefore compared our measurements of many corresponding parameters in both strains: growth rate, energy intake, digestive efficiency, metabolic rate and its components, organ masses, and intestinal brush-border nutrient transporter and hydrolase activities and capacities, as functions of age and body mass in zero- to nine-week-old chicks. Both strains prove to have the same digestive efficiency. Compared to equal-sized jungle fowl, broilers have higher daily energy intake and activity costs. Broilers have relatively longer and wider, hence heavier, small intestines, and their other gut compartments are also relatively larger. Offsetting these increases, broilers have relatively smaller brains and leg bones, these being much less important to a captive bird than to a wild bird exposed to predators. Broilers have generally lower intestinal transporter activities, but relatively higher transporter capacities because of their larger guts. Among domestic chicken strains, comparison of broilers with layers, the former having been consciously selected for much higher growth rates, yields generally similar conclusions. Thus, as recognized in broad outline by Darwin, domestication provides clear examples of conscious selection, of unconscious selection for traits prerequisite to the consciously selected traits, and of unconscious selection against traits rendered less important or competing for space or energy.     

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.     

Single locus typing of MHC class I and class II B loci in a population of red jungle fowl

In species with duplicated major histocompatibility complex (MHC) genes, estimates of genetic variation often rely on multilocus measures of diversity. It is possible that such measures might not always detect more detailed patterns of selection at individual loci. Here, we describe a method that allows us to investigate classical MHC diversity in red jungle fowl (Gallus gallus), the wild ancestor of the domestic chicken, using a single locus approach. This is possible due to the well-characterised gene organisation of the ‘minimal essential’ MHC (BF/BL region) of the domestic chicken, which comprises two differentially expressed duplicated class I (BF) and two class II B (BLB) genes. Using a combination of reference strand-mediated conformation analysis, cloning and sequencing, we identify nine BF and ten BLB alleles in a captive population of jungle fowl. We show that six BF and five BLB alleles are from the more highly expressed locus of each gene, BF2 and BLB2, respectively. An excess of non-synonymous substitutions across the jungle fowl BF/BL region suggests that diversifying selection has acted on this population. Importantly, single locus screening reveals that the strength of selection is greatest on the highly expressed BF2 locus. This is the first time that a population of red jungle fowl has been typed at the MHC region, laying the basis for further research into the underlying processes acting to maintain MHC diversity in this and other species.     

Individual recognition of parental calls by bank swallow chicks (Riparia riparia)

Antiphonal responses of newly fledged bank swallows (Riparia riparia) to the calls of their parents during the joined flights to and from the home burrow suggest that recognition of parents by offspring is a mechanism promoting family cohesion, a necessary condition for the adequate provisioning of chicks in this highly colonial species. Paternal and maternal calls used while leading chicks revealed higher inter-than intra-individual variability in temporal and frequency parameters, indicating that these calls could reliably identify individuals. When tested in the field at the onset of the fledging period, chicks answered significantly more playbacks of parent calls than of alien adult calls. Quantified observations of the rearing activity of the parents suggest that chick-parent recognition is based on familiarity, because of the chicks' differential exposure to the parental calls prior to fledging. During the development of the chicks in the burrow, both parents (which share the rearing activities equally) often call before feeding the chicks.     

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.     

Time-Dependent Increase in Release of Arachidonic Acid Following Passive Avoidance Training in the Day-Old Chick

Abstract: We have investigated the role of arachidonic acid, a putative retrograde messenger, in a one-trial aversive learning task in the day-old chick. The left and right intermediate medial hyperstriatum ventrale (IMHV) in the chick forebrain have previously been implicated in the formation of memory for this task. Using an ex vivo technique we have determined the concentrations of various fatty acids liberated from prisms prepared from these brain regions at different time points up to 24 h following passive avoidance training. At 30, 60, and 75 min post-training the concentration of arachidonic acid, but not of other fatty acids, in prisms prepared from the left IMHV, but not the right IMHV, was enhanced compared with that in chicks trained on a nonaversive water-coated bead. To test whether arachidonic acid liberation from the left IMHV was receptor-stimulated we showed that (a) liberation of endogenous arachidonic acid from homogenate prepared from the left and right IMHV of untrained chicks was stimulated by depolarization with KCl (50 m M ) and that (b) glutamate agonists of the NMDA and metabotropic subtypes of glutamate receptor stimulated release of preloaded [¹⁴C]arachidonic acid from prisms prepared from the left IMHV but not the right IMHV. These results indicate that arachidonic acid is liberated from the left IMHV following passive avoidance training in the day-old chick and may play a role as a retrograde messenger in this memory task.     

Cardiac response of domestic chickens to hawk and goose models

The response of precocial birds to configurational stimuli has been a source of controversy for decades. In this experiment we measured cardiac response of domestic chicks to “hawk” and “goose” silhouettes. The chicks' heart rates varied more in response to the hawk model than to the goose model, suggesting that the hawk silhouette is a more fearful stimulus than that of the goose. Our data document the recognition of a configurational stimulus without prior, pertinent experience.     

Searching behaviour towards a disappearing prey in the domestic chick as affected by preliminary experience

Chicks of 6 days of age were repeatedly presented with a mealworm which disappeared behind one of two screens. They all learned rapidly to look for the worm behind either screen; at a later stage of the training procedure a minority of birds spontaneously restricted their search to the correct side. By providing different types of prior experience it was possible to influence the nondirectional and the directional aspect of the chicks' searching behaviour selectively. The results are discussed with regard to the problem of object permanence, a concept which so far has been mainly studied in child psychology, but which can also be investigated on the level of animal behaviour.