Indoor husbandry of the panther chameleon Chamaeleo [Furcifer] pardalis: Effects of dietary vitamins A and D and ultraviolet irradiation on pathology and life-history traits

To assess the importance of diet and light for indoor maintenance, hatchling panther chameleons were reared for 1 year on crickets fed diets that differed in vitamin concentrations and in different light environments. Dietary transfer of vitamins from the cricket diet to the lizards via the crickets was quantified, as was UV irradiance. There was a statistically significant dietary enhancement of growth by both vitamins on males. UV-A irradiation significantly suppressed growth of females. Low vitamin A shortened life span and resulted in a number of gross and histological pathologies. Hepatocellular lipidosis, indicating a possible toxicosis, occurred with all diets and light treatments. Higher vitamin A resulted in mild soft-tissue mineralization, and high vitamin D shortened the life span of females. Low vitamin A drastically reduced reproduction in both sexes. The intermediate levels of dietary vitamins resulted in the best production of viable eggs by females. However, without high UV-B irradiation, all viable eggs died at term and contained different vitamin levels than hatching eggs from wild-caught females. Baseline levels of egg calcium are given for hatching eggs from wild-caught females. Modifications in current husbandry procedures are recommended. © 1996 Wiley-Liss, Inc.     

Individual female clutch identification through yolk protein electrophoresis in the communally breeding guira cuckoo (Guira guira)

Avian communal breeding systems generate alternative behavioural strategies for females, resulting in differences in reproductive success. Identifying eggs of different females in such systems is problematic, however, due to egg destruction before incubation, difficulty of capturing adults, and/or inaccuracy of egg identification based on egg morphometry. Here, we describe a technique that uses electrophoresis of yolk proteins to determine egg ownership, which we applied to communally breeding guira cuckoos (Guira guira). Validation of the method included identical yolk protein banding patterns in all eggs of the same female, but different patterns in eggs of different females in budgerigars (Melopsittacus undulatus), and identical patterns in yolk follicles of the same females in guira cuckoos. We applied the protocol to 195 guira cuckoo eggs from 34 joint nests in 2 years. All multiple guira cuckoo eggs laid on the same day in single nests had distinct banding patterns of yolk proteins, practically eliminating the possibility of more than one female being represented by the same pattern. Some identical banding patterns were repeated in different days within a nesting bout, indicating that some females laid several eggs in shared nests. Identical patterns occasionally occurred in renestings of groups, indicating that some females lay eggs in consecutive nestings. Yolk protein electrophoresis is a useful tool to identify egg maternity in other circumstances, such as polygynous mating systems with joint nests and intraspecific parasitism. Additionally, it is an alternative method for species where electrophoresis of egg white proteins does not show sufficient polymorphism.     

Some evidence for different ecological pressures that constrain male and female body size

The dwarf morph of the Lake Tanganyika cichlid Telmatochromis temporalis uses empty snail shells as shelters and breeding sites in shell beds, in which many empty shells exist. Here, we assessed selection forces regulating body size in this fish. Field observations showed that large males tended to have a greater number of females in their territories, suggesting that sexual selection favours large males. Nonetheless, a transplant experiment suggested that male body size was limited by the ability to hide in empty shells from large piscivorous fish. In females, the number of ovarian eggs increased with body size, suggesting that fecundity selection favours large females. However, females are smaller than males. Females spawned eggs close to the apices inside the shells. The small space there would decrease the risk of egg predation by egg predators, and small body size of females may be a result of adaptation to spawn eggs in the small, safe spaces. This study provides support for the idea that male and female body sizes have been limited by different ecological pressures (predation on adult fish in males, predation on eggs in females), which has not been reported previously in any animal.     

Proteomic analysis of pikeperch seminal plasma provides novel insight into the testicular development of domesticated fish stocks

Control of the reproduction of domesticated stocks is considered a prerequisite for aquaculture development of pikeperch. However, knowledge about the physiology of the captive pikeperch male reproductive system and the biology of semen is very limited, especially regarding protein characteristics. The aims of our study were to characterize pikeperch sperm quantity and quality parameters and to analyze changes in the proteome of the same males spawned for the first and second times. Moreover, attempts were made to generate the first proteomic library of seminal plasma proteins. Semen collected during the first spawning season was characterized by lower sperm concentration and volume than for the second season. Using mass spectrometry-based label-free quantitative proteomics, we identified 850 proteins in the seminal plasma of pikeperch from both spawning seasons, and 65 seminal proteins were found to be differentially abundant between the first and second spawning seasons. The majority of differentially abundant proteins were involved in stress and immune responses, developmental processes, cofactor metabolic processes, proteolysis, cellular oxidant detoxification and organization of the extracellular matrix (ECM). In addition, several proteins unique to pikeperch seminal plasma were identified, including antifreeze proteins, hibernation-specific plasma proteins, lectins and vitellogenin. In summary, our results indicate that males that spawned for the first time were characterized by incompletely mature gonads and the expression of proteins associated with the early phase of spermatogenesis and ECM organization. On the other hand, males that spawned for the second time exhibited advanced gonadal maturation and expression of proteins related to the late stage of spermatogenesis and sperm maturation, including regulation of reactive oxygen species generation, bicarbonate production, sperm elongation and separation. The identification of a large number of seminal plasma proteins provides a valuable resource for understanding the functions of seminal plasma and the molecular mechanisms involved in testicular development and maturation in domesticated fish, which is a prerequisite for better control of reproduction in captivity.     

Length rather than year‐round spawning,affects reproductive performance of RAS‐reared F‐generation pikeperch,Sander lucioperca (Linnaeus, 1758) – Insights from practice

The continuous production of large numbers of high quality gametes is essential for aquaculture, particularly in candidate species, such as pikeperch, Sander lucioperca (L.). The common practice of year‐round reproduction is under suspicion of inflicting adverse effects on the quality of the gametes through the disturbance of endogenous rhythms. We hypothesized that such perturbation does not affect RAS‐reared F‐generation broodstock. Reproductive performance (number of eggs) and gamete quality (fertilization and hatching rate) were assessed over the course of 3 years covering six independent, photothermal shifted spawning seasons in a commercial pikeperch hatchery (n = 31 egg batches of F‐generation fish in total). No substantial differences in fertilization or hatching rates could be detected between the individual spawning seasons. Fecundity varied, but there are indications for a size effect on female fecundity with intermediate sized females producing higher number of eggs (~65–70 cm). Low egg quality could be detected in batches of very large fish. In conclusion, size‐specific broodstock composition, but not year‐round reproduction of F‐generation pikeperch spawners affects the reproductive performance.     

A comparative proteomic study of the undeveloped and developed Schistosoma mansoni egg and its contents: The miracidium, hatch fluid and secretions

The schistosome egg is the key agent responsible both for transmission of the parasite from human to molluscan host, and is the primary cause of pathogenesis in schistosomiasis. Characterisation of its proteome is a crucial step in understanding the egg’s interactions with the mammalian host. We devised a scheme to isolate undeveloped eggs from mature schistosome eggs by Percoll gradient and then fractionate the mature egg into miracidial, hatch fluid and secreted protein preparations. The soluble proteins contained within the five preparations were separated by two-dimensional electrophoresis and their spot patterns compared by image analysis. Large numbers of representative spots were then excised and subjected to tandem mass spectrometry to obtain identities. In this way, the principal components of each sub-proteome were established. Chaperones were the most abundant category, with heat shock protein 70 (HSP70) dominant in the undeveloped egg and Schistosoma mansoni protein 40 (Smp-40) in the miracidium. Cytoskeletal proteins were expressed at similar levels in the undeveloped egg and miracidium, with tubulins the most abundant. The proteins of energy metabolism reflected the change from anaerobic to aerobic metabolism as the miracidium developed. None of the above categories was abundant in the hatch fluid but this peri-miracidial compartment was highly enriched for defence proteins such as thioredoxin. Hatch fluid also contained several host proteins and schistosome proteins of unknown function, highlighting its distinct nature and potentially its role. The egg secretions could not be compared with the other preparations due to their unique composition featuring the previously characterised IL-4-inducing principal of S. mansoni eggs (IPSE), Omega-1, egg secreted protein 15 (ESP15), a micro-exon gene 2 (MEG-2) protein and two members of the recently described MEG-3 family. This last preparation contains the subset of egg proteins that probably enables eggs to escape from host tissues and may also initiate granuloma formation, emphasising the need to establish fully the roles of its components in schistosome biology.     

First Insight into Exploration and Cognition in Wild Caught and Domesticated Sea Bass (Dicentrarchus labrax) in a Maze

European sea bass aquaculture is so recent that very little is known on the effects of the early steps of its domestication. Behavioural parameters are sensitive indicators of the domestication process since they are generally impacted as soon as the first generation. The present work compared wild-caught and domesticated sea bass juvenile swimming activity, exploration and ability to learn to discriminate between two 2-D objects associated to a simple spatial task that enabled the tested individual to visually interact with an unfamiliar congener (the reward) located behind a transparent wall at the end of one of the two arms of a maze. Ten fish from each origin were individually tested 3 times in a row during 3 days (9 trials in total). Fish were placed in a start box closed by a transparent wall located in front of two 2-D objects. Fish were filmed during 10 min after the removal of the start box wall. Different swimming variables including angular velocity, total distance travelled and velocity mean, were analyzed from videos as well as the time spent in each of 6 virtual zones including the reward zone near the congener (Cong) and the zone opposite to the reward zone (OpCong). Two learning criteria were chosen: the number of successful turns and time to reach Cong. Behavioural differences were found between domesticated and wild fish. Angular velocity was higher in wild fish while the distance travelled and the velocity mean were higher in domesticated ones. Wild and domesticated fish spent most of the time in Cong and in OpCong. No differences were seen in learning ability between wild and domesticated fish. However, our findings for learning require confirmation by further studies with larger numbers of learning sessions and experiments designed to minimise stress. This study therefore demonstrated an impact of domestication on swimming behaviour but not on spatial learning.     

Breeding seasons and laying patterns of the southern African Ostrich Struthio camelus

Wild Zimbabwe Ostriches Struthio camelus were studied during four successive years. Information on breeding seasons and laying patterns was compared with that of domesticated South African hybrid Ostriches in Bophuthatswana. In wild populations laying occurred mainly from July to December or early January, while domesticated birds continued until at least the end of February. Domesticated birds normally laid about 16 eggs in succession, one every second day. There was marked synchronisation of laying and the middle of each successive peak in egg production was about 6 weeks from the preceding peak. Wild birds laid up to eight eggs in any one nest, and normally clutches were contributed by three females, the average combined clutch being 12 or 13 per nest. Circumstantial evidence suggests that individual females may lay in more than one nest during a single laying sequence. Comparisons between rainfall patterns and laying rhythms proved inconclusive.     

Individual Variation in Trophic Egg Production: Evidence for Maternal Manipulation in Response to Resource and Competition Levels

Females of the subsocial shield bug Parastrachia japonensis (Heteroptera: Parastrachiidae) incorporate trophic eggs (nutritive eggs) into their egg mass. Considerable variation occurs among females in trophic egg number and the proportion of an egg mass that is composed of trophic eggs. Because trophic eggs are essential to the development and survival of young, this variation could significantly impact female fitness. We tested the hypothesis that trophic egg abundance is induced by maternal phenotype (weight, body size) and resource exposure. We predicted that resource limitations would cause females to produce fewer fertile eggs and more trophic eggs and that larger and heavier females would produce more of each egg type. Females ovipositing early in the season are exposed to different resource conditions than those that oviposit late. Thus, we compared egg production patterns between these two groups and several other factors related to nesting. No correlation was seen between body size and trophic egg abundance, or, indeed, egg production, overall; however, heavier females produced heavier egg masses. Counter to our prediction, late females, which had greater access to food, produced significantly more total eggs, fewer fertile eggs, and more trophic eggs than early females. A binomial generalized linear model analysis indicated that the factors most correlated with the percentage of an egg mass destined to become trophic eggs were resource abundance, resulting from early or late oviposition, and distance of the nest from the host tree, with closer females producing more trophic eggs. The findings support our hypothesis that resource availability and, to a lesser extent, maternal phenotype affect trophic egg abundance.     

Effects of maternal stress on egg characteristics in a cooperatively breeding fish

Elevated stress experienced by a mother can compromise both her own reproductive success and that of her offspring. In this study, we investigated whether chronically stressed mothers experienced such effects in cooperatively breeding species, in which helpers at the nest potentially compound the negative effects of maternal stress. Using Neolamprologus pulcher, a group-living cichlid fish from Lake Tanganyika, we observed the effects of experimentally increased stress on female reproductive success (measured as inter-spawn interval, and number of eggs) as well as egg characteristics including egg size and cortisol concentrations. Stress levels were manipulated by repeated exposure to the acute stresses of chasing and netting. Stressed females had longer inter-spawn intervals and laid fewer, smaller eggs. Although no significant differences in egg cortisol concentrations were detected between control and stressed females, egg cortisol concentration fell between spawns in control but not in stressed fish. No effect of helper number was detected for any parameter examined, except there appeared to be less change in egg cortisol content in groups with helpers present. Our results suggest that stress imposes fitness costs on breeding females, and social regulation of a dominance hierarchy does not appear to exacerbate or alleviate the negative effects of maternal stress.     

Pigment limitation and female reproductive characteristics influence egg shell spottiness and ground colour variation in the house sparrow (Passer domesticus)

One of the hypotheses to explain egg colour variation in birds lays in the context of sexual selection, where egg colour may signal the female’s physical condition and antioxidant capacity. We tested one of the assumptions following from this hypothesis, that eggshell pigment deposition should be limited for females. The study was conducted in a captive house sparrow (Passer domesticus) population over several years under constant environmental conditions. This multi-brooded species lays eggs which vary in ground colour (biliverdin pigment) and in the intensity and distribution of brownish-red spots (protoporphyrin pigment). Spot darkness, spread and ground colour diminished along the laying sequence, suggesting that the deposition of both pigments was limiting for females over the short term. Also, the proportion of eggs with biliverdin diminished in consecutive clutches laid by the same female over the breeding season, suggesting a long-term cost of biliverdin deposition. On the other hand, spots were darker at the end of the breeding season, indicating that protoporphyrin deposition was probably not limited over the long term. This result could indicate a lower capacity for calcium deposition over the long term, which was compensated for by darker spots. Female age also significantly affected the proportion of bluish eggs and spot patterns. Egg pigmentation decreased with age, indicating that senescing passerine females lay less pigmented eggs. Clutch size was positively related to the proportion of bluish eggs and to spot patterns (darker and more evenly spotted). These results are in accordance with assumptions for the sexual selection hypothesis.     

Differential protein expression profile in the liver of pikeperch (Sander lucioperca) larvae fed with increasing levels of phospholipids

A comparative proteomic approach was used to assess the protein expression profile in the liver of 34 days old pikeperch larvae fed from day 10 post hatching, with three isoproteic and isolipidic formulated diets varying by their phospholipid (PL) contents (% dry diet weight): 1.4% (PL1), 4.7% (PL5) and 9.5% (PL9). Using 2D-DIGE minimal labelling of liver extracts, we were able to show 56 protein spots with a differential intensity (p < 0.05) depending on the dietary PL content. Among these spots, 11 proteins were unambiguously identified using nanoLC-MS/MS tandem mass spectrometry. In the PL9 larvae, our results indicate that the glycolytic pathway could be down-regulated due to the under-expression of the fructose biphosphate aldolase B and the phosphoglucomutase 1. Meanwhile, propionyl coenzyme A carboxylase (a gluconeogenic enzyme) was under-expressed. In addition, another gluconeogenic and lipogenic enzyme, pyruvate carboxylase, was identified in 3 different spots as being under-expressed in fish fed with the intermediate PL level (PL5). A high PL content increased the expression of sarcosine dehydrogenase, an enzyme involved in methionine metabolism, along with vinculin, a structural protein. Moreover, several stress proteins (glutathione S-transferase M, glucose regulated protein 75 and peroxiredoxin-1) were modulated in response to the dietary PL level and fatty acid composition. In the larvae fed with the lowest dietary PL content (PL1), over-expression of both GSTM and GRP75 might indicate a cellular stress in this experimental treatment, while the under-expression of Prx1 might indicate a lower defence against oxidative stress. In conclusion, this nutriproteomic approach showed significant modifications of protein expression in the liver of pikeperch larvae fed different PL contents, highlighting the importance of these nutrients and their influence on metabolism processes and on stress response.     

鱼类卵子质量研究及其关键科学问题

卵子质量(卵质)是一种复杂的生物学特性,是决定雌性动物生殖能力的主要因素。鱼类卵质通常指卵子的受精能力及支持胚胎正常发育的能力,它直接关系到受精卵的形成、胚胎的早期发育及仔、稚、幼鱼的成活与生长,是决定鱼类繁育成功和养殖效率的首要环节。对卵质进行客观而准确的评估,提升卵子质量,以获得大量高质量的成熟卵,是水产种业和养殖业发展的重要前提。理论上,鱼类的卵质由卵子中所储存的所有母源物质的集合及其时空分布格局所共同决定。文章综述了鱼类卵子的发生和成熟及鱼类卵质评估标准的研究现状,重点评述了以斑马鱼为模型所开展的母源因子对卵子质量的调控研究。最后,提出了鱼类卵质研究中亟待研究和解决的重要科学问题,即需要重点研究卵原细胞-卵母细胞转换、卵母细胞-卵子转换、卵-胚转换、胚胎-仔鱼转换、仔-稚鱼转换等决定卵质和受到卵质影响的关键生物学事件。     

Proteomic analysis of egg white proteins during the early phase of embryonic development

Avian egg albumen participates in embryonic development by providing essential nutrients as well as antimicrobial protection. Although various biological functions of egg white proteins were suggested during embryogenesis, global changes of these proteins under incubation conditions remained uninvestigated. This study presents a proteomic analysis on the change of egg white proteins during the first week of embryonic development. By using 2-DE, together with MALDI-TOF MS/MS, thirty protein spots representing eight proteins were identified showing significant changes in abundance during incubation. An accelerating degradation of ovalbumin was observed in a wide range of molecular weight. In addition, four protein complexes were predicted according to the detected molecular weight increase. Among these speculated protein complexes, an ovalbumin spot coupled with RNA-binding protein was detected. The absence of these protein complexes before incubation, followed by the constant increase in abundance during incubation indicates conceivable pivotal roles in embryonic development. To better understand the function of the proteins identified in this study, discrepancies of egg white protein changes between fertilized and unfertilized chicken eggs were additionally demonstrated. These findings will provide insight into the embryogenesis process to improve our knowledge of egg white proteins in regulating and supporting early embryonic development.     

Ovarian follicular development, lipid peroxidation, antioxidative status and immune response in laying hens fed fish oil-supplemented diets to produce n-3-enriched eggs

The objective of the present study was to research the effect of feeding laying hens fish oil-supplemented diets to produce n-3-enriched eggs on their ovarian follicular development, serum lipid peroxidation, antioxidative status and immune response. A total of 105 white Bovens hens at 24 weeks of age were housed in cages in an open-sided building under a 16 h light : 8 h dark lighting schedule. Birds were randomly divided into five treatments and were fed, ad libitum, diets containing 0% (control), 1.25%, 2.5%, 3.5% or 5.0% fish oil from 24 to 36 weeks of age. Egg production and weight were recorded. By weeks 35 and 36 of age 15 eggs were taken at random from each treatment to determine the yolk lipid profile and cholesterol content. At the end of the experimental period, 10 females from each treatment were randomly chosen, anaesthetised and killed by decapitation. Ovary and oviduct samples were immediately weighted and ovarian follicles were classified. Serum thiobarbituric acid-reactive substance (TBARS), hepatic TBARS and hepatic glutathione peroxidase (GSH-Px) activity were measured. No clear trend was observed concerning egg production and egg yolk cholesterol. As dietary fish oil levels increased, n-3-polyunsaturated fatty acids (n-3 PUFA) increased, whereas n-6 PUFA tended to decrease in yolk lipids. No negative effects were detected in ovary and oviduct weights, expressed in both absolute terms and relative to body weight. The numbers and total weights of large yellow follicles (LYF) in the ovary were not significantly affected by fish oil supplementation. Low levels (1.25% to 2.5%) of fish oil reduced both plasma and hepatic TBARS and enhanced GSH-Px activity. It is also interesting to note that inclusion of 2.5% fish oil in laying hen diets enhanced the antibody titre in laying hens. Therefore, it could be concluded that inclusion of fish oil in laying hen diets at moderate levels increased the n-3 fatty acids content in eggs, improved antioxidative status, enhanced the antibody response and did not have a negative influence on the different reproductive morphology parameters in laying hens.     

Fatty acid signatures of female Brünnich's guillemots Uria lomvia suggests reliance on local prey for replacement egg production

The laying of smaller replacement eggs has been described as a time-saving adaptation because chicks generally grow faster once hatched than inside the egg. However, chicks hatched from smaller eggs have, potentially, lower survival. Consequently, the smaller replacement egg represents a benefit to the female in terms of preserving its own condition at a cost to their offspring. We test these ideas by measuring adult mass changes and plasma lipid concentration changes in male and female Brünnich's guillemots Uria lomvia breeding on Coats Island, Nunavut. Though males lost more mass than females, these differences were not significant. Between laying the first and replacement egg, plasma fatty acid concentrations declined in females and increased in males, suggesting that females mobilise less lipid to preserve their condition after laying the replacement egg. In females, plasma lipid concentrations of the dominant fatty acids found in the eggs (16:0 and 18:1) declined between the laying of first and replacement eggs while plasma concentrations of 20:1 increased in both males and females. We compared the fatty acid signatures of first and replacement egg to look for evidence of differences between the lipid sources for their production. Principal component and discriminant function analyses showed that the fatty acid signatures of replacement eggs were closer to the signatures of the local prey than those of first eggs. We suggest that females rely on local sources of energy to a greater degree for the production of the replacement egg than the first egg, but that endogenous reserves of certain nutrients are important for the production of both eggs.     

Do marine birds use environmental cues to optimize egg production? An experimental test based on relaying propensity

According to the environmental cues hypothesis, female birds use information available to them in the early‐season environment to fine‐tune egg production annually. However, support for the hypothesis derives largely from correlational studies. In each year from 2002 to 2006, which spanned a period of extreme variation in environmental conditions, we removed eggs from early‐laying rhinoceros auklets Cerorhinca monocerata, burrow‐nesting seabirds that lay a single‐egg clutch. We then measured their relaying rates, relaying intervals, and breeding success. We also monitored the timing and success of breeding in control pairs, and control chick diets. If the experimental females base their relaying decision on early‐season cues, then we predict that few will relay in years in which early‐laying control birds breed unsuccessfully, and in which a preferred prey species, Pacific sandlance Ammodytes hexapterus, is in short supply in nestling diets. Results matched neither prediction. In each year, almost all (88–90%) of the experimental females relaid, despite that the control pairs’ breeding success (32–87% fledged chicks), and their chicks’ diets (twofold variation in proportion of sandlance), varied markedly. We conclude that female rhinoceros auklets did not modify their relaying decision in response to variation in environmental conditions, although relaying intervals and their own breeding success (0–78%) covaried negatively. Our results may have important implications related to using seabirds as monitors of the marine environment.