Glucose-6-phosphate dehydrogenase and NADP-linked malate dehydrogenase during posthatching development of brain of altricial birds

Glucose-6-phosphate dehydrogenase and NADP-linked malate dehydrogenase were studied in different areas of the brain of three altricial birds during posthatching development. The birds were pigeon and swift, having a posthatching nestling period of 30 days; and sparrow, having a posthatching nestling period of 14 days. The activity of the two enzymes was high during development. G-6-PD activity may be high because of the need for pentoses in the early part of development and the need for reducing equivalents (NADPH₂) for synthesis of lipids and other compounds in the later stages of development. Malic enzyme activity also seems to be high because of the need for reducing equivalents. The activity of malic enzyme was found to be higher than that of G-6-PD.     

Occurrence of keratinophilic fungi on Indian birds

Keratinophilic fungi were isolated from feathers of most common Indian birds,viz. domestic chicken (Gallus domesticus), domestic pigeon (Columba livia), house sparrow (Passer domesticus), house crow (Corvus splendens), duck (Anas sp.), rose-ringed parakeet (Psittacula krameri). Out of 87 birds, 58 yielded 4 keratinophilic fungal genera representing 13 fungal species and one sterile mycelium. The isolated fungi were cultured on Sabouraud's dextrose agar at 28±2°C.Chrysosporium species were isolated on most of the birds.Chrysosporium lucknowense andChrysosporium tropicum were the most common fungal species associated with these Indian birds. Maximum occurrence of fungi (47%) was recorded on domestic chickens and the least number of keratinophilic fungi was isolated from the domestic pigeon and duck. The average number of fungi per bird was found to be the 0.44.     

Timing of incorporation of docosahexaenoic acid into brain and muscle phospholipids during precocial and altricial modes of avian development

We investigated the possibilities that the proportion of docosahexaenoic acid (DHA) in phospholipids of brain and skeletal muscle at hatch, and the ontogenetic timing of the DHA accretion spurt in these tissues, might serve as indices of neonatal functional maturity that discriminate between precocial and altricial avian developmental modes. Comparison of the fatty acid profiles of the initial and residual yolks of two free-living altricial species, the swallow (Hirundo rustica) and the sparrow (Passer domesticus), reveals that, in contrast to precocial birds, there is no preferential uptake of DHA from the yolk during embryonic development. At hatch, the proportions of DHA in brain phospholipid (wt.% of fatty acids) of the swallow and sparrow, at 8.1% and 5.0%, respectively, are far lower than the values (16.9-19.6%) reported for non-altricial species. This reflects a marked difference in the timing of the brain DHA accretion spurt, which occurs during the first half of the embryonic period of precocial birds, but is largely delayed until after hatching in the altricial species. By the time of fledging, the proportion of DHA in the swallow brain phospholipid has increased to 14.3%. For non-altricial birds, the brain DHA concentration at hatch shows little interspecies variation, despite major differences in yolk DHA content. The proportions of DHA in leg muscle phospholipid of the newly hatched swallow and sparrow, at 2.9% and 2.5%, respectively, are far lower than the value (6.7%) for the precocial chicken. Again, this relates to differences in developmental timing, with muscle DHA accretion occurring in the first half of the chicken's embryonic period, whereas, in the swallow, this increase is delayed until after hatching. By the time of fledging in the swallow, DHA forms 9.3% of muscle phospholipid fatty acids, equivalent to the level attained in chicken muscle at the mid-embryo stage. The results indicate a clear distinction between altricial and non-altricial avian species in the timing of tissue DHA accretion during development, presumably reflecting differences in neonatal functional maturity.     

Long-term trends in first arrival and first egg laying dates of some migrant and resident bird species in northern Italy

Climate change is affecting the phenology of seasonal events in Europe and the Northern Hemisphere, as shown by several studies of birds’ timing of migration and reproduction. Here, we analyse the long-term (1982–2006) trends of first arrival dates of four long-distance migratory birds [swift (Apus apus), nightingale (Luscinia megarhynchos), barn swallow (Hirundo rustica), and house martin (Delichon urbicum)] and first egg laying dates of two migrant (swift, barn swallow) and two resident species [starling (Sturnus vulgaris), Italian sparrow (Passer italiae)] at a study site in northern Italy. We also addressed the effects of local weather (temperature and precipitation) and a climate index (the North Atlantic Oscillation, NAO) on the interannual variability of phenological events. We found that the swift and the barn swallow significantly advanced both arrival and laying dates, whereas all other species did not show any significant temporal trend in either arrival or laying date. The earlier arrival of swifts was explained by increasing local temperatures in April, whereas this was not the case for arrival dates of swallows and first egg laying dates of both species. In addition, arrival dates of house martins were earlier following high NAO winters, while nightingale arrival was earlier when local spring rainfall was greater. Finally, Italian sparrow onset of reproduction was anticipated by greater spring rainfall, but delayed by high spring NAO anomalies, and swift’s onset of reproduction was anticipated by abundant rainfall prior to reproduction. There were no significant temporal trends in the interval between onset of laying and arrival in either the swift or the barn swallow. Our findings therefore indicate that birds may show idiosyncratic responses to climate variability at different spatial scales, though some species may be adjusting their calendar to rapidly changing climatic conditions.     

Ontogenetic patterns of constitutive immune parameters in altricial house sparrows

Innate immune functions are proposed to develop rapidly post‐hatch in altricial nestlings, compared with adaptive immune defenses that require development of receptor specificity and memory. Studies of ontogenetic changes in altricial birds have been few until relatively recently and often do not encompass the entire developmental period. We examined the patterns of development in constitutive innate and adaptive immune indices in house sparrow nestlings (3, 6, 9 and 12 days (d) post‐hatch), hatch‐year birds and adults. Lysozyme activity significantly decreased with age, likely representing catabolism of maternal investment of lysozyme in the egg albumen. Levels of total IgY (indexing adaptive immune function), as well as agglutination and lysis (indexing innate immune function), increased throughout the nestling period, but were significantly below levels found in fully‐grown birds at the time of fledging. There were no significant differences between hatch‐year birds and adults in these measures, indicating that rapid, full maturation occurs early in the post‐fledging period. In combination with previous studies, these data highlight the importance of sampling fledglings to assess full immune ontogeny and suggest that fledgling birds may be more vulnerable to infection than adults.     

Changes in catecholamines and dopaminergic metabolites in pigeon brain during development from the late embryonic stage toward hatch

While brain development during embryogenesis has been extensively studied in precocial birds, there is no information available on altricial birds. Thus, the concentrations of the catecholamines norepinephrine (NE), epinephrine (E), and dopamine (DA), and the dopaminergic metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and 4-hydroxy-3-methoxyphenylacetic acid (HVA) were determined at several stages during the late embryonic period (E13, E14, E15, E16, E17 and E18) and the day-of-hatch (P0) in the pigeon telencephalon, cerebellum, optic lobe, and brainstem. The concentrations of all catecholamines were higher than those reported in chicken embryos. During embryogenesis, NE, E, DOPAC and HVA concentrations in the various brain parts increased throughout embryonic development until shortly before hatching at which time they decreased. DA, however, continued to increase through hatching in the brainstem, and the changes in DA concentrations varied in several brain parts. In conclusion, catecholamine concentrations in the various brain parts tended to increase with embryonic age, and the concentrations were higher than those in chickens. Furthermore, brain catcholamine metabolism changed at hatch in pigeons.     

Effect of intranasal irrigation with zinc sulphate on male-induced oestrus in the wild mouse, Mus musculus domesticus

Adult males of the subtropical house sparrow (Passer domesticus) were subjected to continuous darkness (DD) or short days (8L:16D) after photostimulation (15L:9D) for 30 days. One group was retained on the long day (15L:9D) schedule. Another two groups of photosensitive birds were placed under DD or 8L:16D. The photostimulated birds under DD or 8L:16D showed testicular regression and the rate of regression was similar in both the treatments. The photosensitive birds, on the other hand, did not show any initiation in testicular growth and development in either of the treatments. Long day birds (15L:9D) maintained enlarged testes without regression (the onset of photorefractoriness) during the treatment period. These results conform with the external coincidence model, but could also be explained by a modified internal coincidence model.     

Hybrid speciation in sparrows I: phenotypic intermediacy,genetic admixture and barriers to gene flow

Homoploid hybrid speciation is thought to require unusual circumstances to yield reproductive isolation from the parental species, and few examples are known from nature. Here, we present genetic evidence for this mode of speciation in birds. Using Bayesian assignment analyses of 751 individuals genotyped for 14 unlinked, nuclear microsatellite loci, we show that the phenotypically intermediate Italian sparrow (Passer italiae) does not form a cluster of its own, but instead exhibits clear admixture (over its entire breeding range) between its putative parental species, the house sparrow (P. domesticus) and the Spanish sparrow (P. hispaniolensis). Further, the Italian sparrow possesses mitochondrial (mt) DNA haplotypes identical to both putative parental species (although mostly of house sparrow type), indicating a recent hybrid origin. Today, the Italian sparrow has a largely allopatric distribution on the Italian peninsula and some Mediterranean islands separated from its suggested parental species by the Alps and the Mediterranean Sea, but co‐occurs with the Spanish sparrow on the Gargano peninsula in southeast Italy. No evidence of interbreeding was found in this sympatric population. However, the Italian sparrow hybridizes with the house sparrow in a sparsely populated contact zone in the Alps. Yet, the contact zone is characterized by steep clines in species‐specific male plumage traits, suggesting that partial reproductive isolation may also have developed between these two taxa. Thus, geographic and reproductive barriers restrict gene flow into the nascent hybrid species. We propose that an origin of hybrid species where the hybrid lineage gets geographically isolated from its parental species, as seems to have happened in this system, might be more common in nature than previously assumed.     

Molecular genetics of avian proteins. XIII. Protein polymorphism in three species of Australian passerines.

An introduced species, the house sparrow (Passer domesticus), and two Australian native species, the welcome swallow (Hirundo tahitica neoxena) and the fairy martin (Petrochelidon ariel), have moderately low levels of protein polymorphism compared with domesticated or semi-wild 'managed' species of birds. Genetically varient proteins in these birds include transferrin, esterase, phosphoglucomutase, NADP-dependent isocitrate dehydrogenases, phosphogluconate dehydrogenase (decarboxylating) and glucose-6-phosphate dehydrogenase. Egg-white protein polymorphism confirms heterogeneity of egg colour, markings and shape, and suggests that approximately 10% of the 'clutches' in house sparrow nests represent infidelity (intraspecific nest parasitism). For the four enzymes capable of supplying reduced NADP for reductive biosyntheses in growth and detoxification, the house sparrow has more heterozygosity (29%) than either the welcome swallow (9-4%) or the fairy martin (2-3%) and the difference is highly significant statistically. The results are discussed in relation to possible biochemical correlates of MacArthur and Wilson's (1967) evolutionary strategies or r or K selection.     

Some aspects of the value of Sudan Black B in lipid histochemistry.

The lipid dye Sudan Black B, as generally used to demonstrate lipids in the interior of the cell nucleus, was studied with regard to its staining properties for isolated nuclei in relation with its chromatographic characteristics in solution, as well as with a model system consisting of lipid containing polyacrylamide films. Isolated nuclei are stained with Sudan Black B dissolved in ethylalcohol, only when the dye-solution is at least one month old. Extraction with chloroform-methanol (2:1) before staining resulted in a decrease of 35% in intensity. Treatment with proteolytic enzymes and DNA-se caused a complete disappearance of the staining capacity. The binding of Sudan Black B with phospholipids enclosed in the form of liposomes in modelfilms when stained with this dye in ethylene glycol obeys the law of Lamber-Beer, Proteins were however, also coloured by the dye. The chromatographic experiments showed that the dye is built up from two main and a number of secondary products. The secondary products which increase by aging of the dye-solution, change the spectrophotometric properties of the total dye and show a specific binding. The conclusion was reached that on the basis of a positive reaction with Sudan Black B no definite conclusions can be drawn about the presence of lipids in the interior of the cell nucleus.     

Ontogenetic development of the ophthalmic rete in relation to brain cooling in chickens and pigeons

The brain cooling capacity of the altricial pigeon increases during posthatching growth at a higher rate than that of the precocial duck and chicken. To determine if this difference between the altricial and the precocial modes of development can be related to growth rates of the vascular heat exchanger involved in brain cooling (the ophthalmic rete), we performed a morphometric analysis of this structure during the post-hatching maturation of the three species. The number of vascular units in the rete did not change during development but differed significantly among species. The retia continued to grow in length and diameter in an exponential relation with body mass at similar rates in all species. The surface area of the retial arteries, which reflects the area available for countercurrent heat exchange, also increased exponentially with body mass, but without significant differences among the three species. However, the effectiveness of the rete in brain cooling, as indicated by the degree of brain cooling per unit of heat-exchange area in the rete, was higher in the altricial pigeon than in the precocial chicken and duck. It is concluded that the posthatching morphometric changes in the ophthalmic rete (rete ophthalmicum) are important for the development of brain cooling capacity, but cannot solely explain differences in brain cooling between growing altricial and precocial birds. These differences are most likely related to differences in the maturation of the central thermoregulatory control system and the peripheral effector mechanisms among the two groups of birds.     

Effect of hatching system and prophylactic antibiotic use on serum levels of intestinal health biomarker diamine oxidase in broilers at an early age

To overcome some of the disadvantages of conventional hatcheries, a new concept is being explored in the broiler industry: on-farm hatching. In on-farm hatching systems, broiler eggs are transported to the broiler house on day 18 of incubation. On-farm hatched chicks hatch in a low dust environment, are immediately exposed to light, and have instant access to nutrients and water. Previous studies reported that on-farm hatching systems provide birds with an improved intestinal health and a lower feed conversion rate; resulting in a reduced use of antibiotics. Although it is generally agreed that the intestinal health of on-farm hatched chicks is better, the causative factors remain largely unknown. To explore the effect of hatching system on intestinal development, a full factorial in vivo experiment was designed, taking into account commercial age (minus two days, D-1, D1 and D2) and hatching condition (hatchery-born, hatchery-born with Spectoliphen 100 (SL) treatment, and on-farm hatched using the NestBorn-system) as factors. To assess intestinal development, diamine oxidase (DAO) serum levels were measured. DAO, a highly active intracellular enzyme that is synthesised mainly by the intestinal mucosal cells, is generally used as an indicator for intestinal maturation and intestinal permeability (IP) in mammals and birds. Analysis of serum samples showed that serum DAO levels in hatchery-born chicks were significantly lower compared to their on-farm hatched counterparts on all four days, suggesting that the intestinal development in the latter took place earlier. However, the long-term effect was not explored in this study. An additional comparison between the hatching systems was made, not according to commercial age, but in reference to time of access to feed. In this comparison, no differences between the two groups were observed. Interestingly, in the hatchery-born chicks, no compensatory development of the intestines took place within the time span of this experiment. The effect of SL during the first days on intestinal development and IP of chicks remains poorly understood and requires further investigation.     

Purification and characterization of peroxisomal apo and holo alanine:glyoxylate aminotransferase from bird liver.

Alanine:glyoxylate aminotransferase has been reported to be present as the apo enzyme in the peroxisomes and as the holo enzyme in the mitochondria in chick (white leghorn) embryonic liver. However, surprisingly, birds were found to be classified into two groups on the basis of intraperoxisomal forms of liver alanine:glyoxylate aminotransferase. In the peroxisomes, the enzyme was present as the holo form in group 1 (pigeon, sparrow, Java sparrow, Australian budgerigar, canary, goose, and duck), and as the apo form in group 2 (white leghorn, bantam, pheasant, and Japanese mannikin). In the mitochondria, the enzyme was present as the holo form in both groups. The peroxisomal holo enzyme was purified from pigeon liver, and the peroxisomal apo enzyme from chicken (white leghorn) liver. The pigeon holo enzyme was composed of two identical subunits with a molecular weight of about 45,000, whereas the chicken apo enzyme was a single peptide with the same molecular weight as the subunit of the pigeon enzyme. The peroxisomal holo enzyme of pigeon liver was not immunologically cross-reactive with the peroxisomal apo enzyme of chicken liver, the mitochondrial holo enzymes from pigeon and chicken liver, and mammalian alanine:glyoxylate aminotransferases 1 and 2. The mitochondrial holo enzymes from both pigeon and chicken liver had molecular weights of about 200,000 with four identical subunits and were cross-reactive with mammalian alanine:glyoxylate aminotransferase 2 but not with mammalian alanine:glyoxylate aminotransferase 1.     

Activites of Enzymes Synthesizing Diacyl, Alkylacyl, and Alkenylacyl Glycerophosphoethanolamine and Glycerophosphocholine During Development of Chicken Brain

Abstract: Ethanolamine and choline glycerophospholipids are the major phospholipids of brain membranes. During brain development, the accumulation of these phospholipids is most intense when myelination occurs. In order to gain knowledge about the regulatory mechanisms for synthesis of these lipids in relation to membrane synthesis, we investigated the activities of the 1,2-diradyl-sn-gIycerol: CDPethanolamine phosphoethanolarnine transferase and 1,2-diradyl-sri-glycerol:CDPcholine phosphocholine transferase during chicken brain development. Diacyl, alkenylacyl, and alkylacylglycerols are substrates for both enzymes. The specific activities of microsomal phospho-ethanolamine and phosphocholine transferases are constant between the 8th and 18th day of embryonic life. The specific activities of both enzymes double around hatching, which is the period of intense myelination and marked ac-cumulation of ethanolamine and choline glycerophospholipids in brain. At the same time, the amount of microsomes increases by 50%; thus the total activities increase threefold. Four days after hatching the specific activities of both enzymes are at adult values. Similar results were obtained in the presence of exogenous diacyl or alkylacylglycerols. During brain development the apparent K_m, value of rnicrosomal phosphoethanolamine transferase for CDP ethanolamine increases when assayed with diaclyglycerols or alkylacyl-glycerols a s lipid substrates. The apparent K_m, value of phosphocholine trans-ferase for CDP choline does not change during brain development in the presence of exogenous diacylglycerols, but increases in the presence of exogenous alkylacylglycerols. These changes in K_m, values may be due to the appearance of glial isoenzyme at the beginning of myelination. The apparent K_m, values of diacylglycerol phosphocholine, alklyacylglycerol phosphocholine, and diacyl-glycerol phosphoethanolamine transferases for their CDP bases are similar in adult brain microsomes and are threefold higher than the apparent K_m, value of alkylacylglycerolphosphoethanolamine transferase. The high affinity of alkylacylglycerolphosphoethanolamine transferase for CDPethanolamine may be responsible for the preferential synthesis of ethanolamine plasmalogens in brain.     

Changes in developmental profiles of brain gangliosides during ontogeny of a teleost fish (Sarotherodon mossambicus,Cichlidae)

Summary Ontogenetic changes of brain ganglioside concentration and composition have been followed in the teleost fishSarotherodon mossambicus Cichlidae) from the 1st day post hatching to the adult stage, in order to correlate these with findings in higher vertebrates. During the developmental period from hatching to the transition to free swimming, which comes along with maximum rate of synaptogenesis, a sharp rise in the brain ganglioside content occurs, which is mainly due to the trisialoganglioside GT1b. In the following phase of myelination (characterized in birds and mammals by an increase in GM1, GM1 and GM4) accretion of the novel and so far unidetified fraction (GM2) occurs, which is highly enriched in the brain stem. The results obtained are discussed with respect to gangliosides as useful biochemical markers for brain development and maturation in all vertebrates.     

Experimental infection of five species of raptors and of hooded crows with Francisella tularensis biovar palaearctica

Sixteen raptors and three hooded crows were infected experimentally with Francisella tularensis biovar palaearctica. The birds were infected parenterally or per os. One goshawk, one sparrow hawk and one hooded crow died during the experimental period, and the remaining 16 birds were killed 14-77 days after the first infection. Francisella tularensis was not isolated from any bird. Antibody levels against F. tularensis measured in nine birds varied from 0 to 1:1,280. In one goshawk with a titer of 1:1,280, positive fluorescent antibody reactions against F. tularensis were seen in the liver and spleen. These results are similar to those found by other authors indicating that raptors and corvids are normally resistant to infections with F. tularensis.