Growth of Odontesthes bonariiensis (Atherinidae) larvae feeding on suboptimal zooplankton densities

Synopsis In this study we investigate the effect of food availability (zooplankton biomass) on the growth of Odontesthes bonariensis (Atherinidae) larvae. The larvae were stocked in four 45 m² outdoor tanks at relatively high densities (100 and 200 larvae m^–2). Because of the high stocking densities, the zooplankton biomass was depleted in all tanks. However, the patterns of food limitation, and particularly periods of severe food shortage, differed in tanks stocked at different densities. We could therefore, observe the effect of food limitation in larvae that differed in weight and age. The effects of variables suspected to influence O. bonariensis growth rates (age and weight of larvae, available zooplankton biomass, mean individual weight of available preys, total ingested prey weight, and mean weight of ingested preys) were investigated using standard multiple regression methods, and a model assuming: (1) an allometric relationship between maximum growth rates and weight of larvae, and (2) an inverse relationship between growth depression and the available zooplankton biomass. Both methods were consistent in showing that only the weight of larvae, and the availability of zooplankton prey had significant effects on the growth of O. bonariensis. The model's results additionally suggest that, if the observed growth rates are scaled by the maximum growth rate corresponding to the larva weight, the effect of zooplankton biomass is largely independent of age and weight of larvae.     

Growth of the African elephant (Loxodonta africana)

The three-stage desk calculation of the von Bertalanffy equation to describe growth in height and weight with age in the elephant is compared with a new approach to calculating the three coefficients in the function by a computer. The two methods give different results with respect to the weight/age calculations. Theoretical von Bertalanffy equations calculated by both methods to describe growth in height and weight with age in the African elephant in Zambia are compared with previously published equations for the elephant in East Africa. Details are given of growth in height in two known-age African elephants, a female ‘Diksie’ and a male ‘Kartoum’. Theoretical growth in height curves for the female African and Asiatic elephant are compared. The coefficients K and / for growth in height are not transferable to the growth in weight equations. Inherent inaccuracies in the calculation of the coefficients in the von Bertalanffy equation are discussed, and it is concluded that in animals which have a long life-span such as the elephant, the equation serves as a purely empirical representation of weight-at-age data and that there is little biological significance in the parameters it contains. The computer-calculated curves give the best fit to the data. The regression of log age on log shoulder height from 2–20 years of age provides a more realistic approach to comparative growth studies. The increase in adrenal weight with age is linear. Tusk growth in relation to age and sex in Zambia is compared with East Africa. It is concluded that the tusks in Zambia are smaller and are more difficult to sex correctly than their East African counterparts, possibly a consequence of the Zambian elephant having a greater degree of tusk wear. Allometric growth is described with emphasis on the estimation of body weight from shoulder height. The most reliable estimates are obtained from a purely empirical representation of the data, a semilog plot of log body weight on shoulder height.     

Analyses of factors influencing the birth weight and neonatal growth rate of Cheetah (Acinonyx jubatus) cubs

Birth weight and the neonatal growth rate are reliable indicators of neonatal survival prospects. Data on weight at birth and consecutive weights until 40 days of age were recorded for cheetah cubs in 16 litters. Growth was found to be linear during the first 40 days of life. Weight data were used to evaluate the influence of several factors on birth weight and neonatal growth. The factors used in these analyses were sex, litter identity, litter size, average litter size over the first 40 days, birth weight, parents, gestation length, parity of the dam, and inbreeding. For birth weight and neonatal growth, litter identity was the major explanatory factor (81.8 and 85.3%). For birth weight, a significant influence of gestation length was found (p < 0.05), whereas inbreeding coefficient tended to decrease the birth weight (p = 0.09). Together, gestation length and inbreeding coefficient account for 57.5% of the between‐litter variation for birth weight. Factors with significant influences on neonatal growth are gestation length and parity (p < 0.05). The average litter size over the first 40 days tended to influence neonatal growth (p = 0.07). These three variables together account for 99.9% of the between‐litter variation for neonatal growth during the first 40 days of life. A comparison of neonatal growth between mother‐raised and hand‐raised cubs revealed a lower growth rate in hand‐raised cubs (45 vs. 27 g/day). Zoo Biol 18:129–139, 1999. © 1999 Wiley‐Liss, Inc.     

Growth promotion effect of Fusarium spp. PPF1 from bermudagrass (Cynodon dactylon) rhizosphere on Indian spinach (Basella alba) seedlings are linked to root colonisation

A rhizosphere fungus was isolated from roots of bermudagrass (Cynodon dactylon) and identified as Fusarium spp. PPF1. A pot experiment was conducted to test its ability to promote the vegetative growth of Indian spinach seedlings (Basella alba). Indian spinach seeds were sown in sterilised field soil amended with wheat grain inoculum of PPF1 at the rate of 0.5 and 1.0% w/w, and plants were grown for 21?days in a net house. Significantly, higher germination percentage and vigour index were observed due to application of PPF1 in the potting soil. Treatment with PPF1 also significantly increased shoot length, shoot fresh weight, shoot dry weight, root length, root fresh weight, root dry weight, leaf area and leaf chlorophyll content of cucumber plants compared to non-treated control. The growth promotion rate increased with the increasing concentration of inoculum of PPF1 applied to the soil. The fungus was re-isolated from the roots of cucumber plants at higher frequencies, while a positive co-relation was found between the root colonisation ability and the plant growth enhancement by the isolate. These results suggest that growth promotion effect of Fusarium spp. PPF1 on Indian spinach (B. alba) are linked to root colonisation ability of the fungus.     

Starvation and growth in the gastropod Planorbarius corneus (L.)

The effect of different degrees of partial starvation on growth was studied in the fresh-water gastropodPlanorbarius corneus (L.). Two indices of growth were used, fresh weight and shell diameter, and for both indices the rate of growth decreased proportionately at least as much as the proportion of time that food was absent. This suggests that growth is not regulated in this species, and some doubts are expressed about the validity of results with other invertebrate species that suggest growth is regulated.     

Peculiarities of Philodina roseola (Ehrbg.) (Rotatoria,Bdelloida) – Growth and Reproduction under Various Temperature Conditions

Most investigations dealing with rotifer reproduction have been performed with populations and not with individuals. At the same time the variations in the growth and reproduction rates of rotifers are of considerable interest. This paper presents the results of investigations carried out by culturing individuals of Philodina roseola during the lifespan of an individual under different temperature conditions ranging from 9 to 35 °C. The paper presents curves showing the growth in length and weight, the periods of maximum growth rate and the maximum sizes of Philodina as affected by temperature conditions. The reproduction rate is investigated at the same time. The variation in egg evolution duration, in duration of the reproductive period and in the egg laying rate are shown under all the conditions investigated. The data serve as a basis for estimating the effect of temperature on the productivity of Philodina roseola.     

Body size development of captive and free‐ranging Leopard tortoises (Geochelone pardalis)

The growth and weight development of Leopard tortoise hatchings (Geochelone pardalis) kept at the Al Wabra Wildlife Preservation (AWWP), Qatar, was observed for more than four years, and compared to data in literature for free‐ranging animals on body weight or carapace measurements. The results document a distinctively faster growth in the captive animals. Indications for the same phenomenon in other tortoise species (Galapagos giant tortoises, G. nigra; Spur‐thighed tortoises, Testudo graeca; Desert tortoises, Gopherus agassizi) were found in the literature. The cause of the high growth rate most likely is the constant provision with highly digestible food of low fiber content. Increased growth rates are suspected to have negative consequences such as obesity, high mortality, gastrointestinal illnesses, renal diseases, “pyramiding,” fibrous osteodystrophy or metabolic bone disease. The apparently widespread occurrence of high growth rates in intensively managed tortoises underlines how easily ectothermic animals can be oversupplemented with nutrients. Zoo Biol 29:517–525, 2010. © 2009 Wiley‐Liss, Inc.     

Plant growth‐promoting effects of native Pseudomonas strains on Mentha piperita (peppermint): an in vitro study

Plant growth‐promoting rhizobacteria (PGPR) affect growth of host plants through various direct and indirect mechanisms. Three native PGPR (Pseudomonas putida) strains isolated from rhizospheric soil of a Mentha piperita (peppermint) crop field near Córdoba, Argentina, were characterised and screened in vitro for plant growth‐promoting characteristics, such as indole‐3‐acetic acid (IAA) production, phosphate solubilisation and siderophore production, effects of direct inoculation on plant growth parameters (shoot fresh weight, root dry weight, leaf number, node number) and accumulation and composition of essential oils. Each of the three native strains was capable of phosphate solubilisation and IAA production. Only strain SJ04 produced siderophores. Plants directly inoculated with the native PGPR strains showed increased shoot fresh weight, glandular trichome number, ramification number and root dry weight in comparison with controls. The inoculated plants had increased essential oil yield (without alteration of essential oil composition) and biosynthesis of major essential oil components. Native strains of P. putida and other PGPR have clear potential as bio‐inoculants for improving productivity of aromatic crop plants. There have been no comparative studies on the role of inoculation with native strains on plant growth and secondary metabolite production (specially monoterpenes). Native bacterial isolates are generally preferable for inoculation of crop plants because they are already adapted to the environment and have a competitive advantage over non‐native strains.     

Effects of starvation on growth and reproductive apparatus of two immature freshwater snails Biomphalaria pfeifferi and Biomphalaria glabrata (Gastropoda: Planorbidae)

Starvation of immature snails of Biomphalaria pfeifferi and B. glabrata results in an arrest of growth and animals remain immature. Spermatogenesis is limited to spermatogonia (B.g.) or spermatocytes 1 (B.p.). The number and the size of oocytes remain inferior to that of controls. Animals show reduced genital tracts.Once feeding is restored, growth is resumed but wet weight and shell diameter do not reach the same level as in controls. Fecundity and gametogenesis do not differ from that in controls. Genital tracts weight is proportional to body weight.     

Suitability of bench scale bioreactor system for shoot biomass production and bacoside biosynthesis from Bacopa monnieri (L.)

According to folklore, Bacopa monnieri commonly called as Brahmi is known for its cognitive enhancing properties. The plant is found abundantly in wetlands but the drug content (bacosides) is very low (0.2%), therefore, alternative biotechnological protocols are highly needed to supplement the constant source of this valuable plant material which produces stable amounts of bacosides. The present study was conducted to explore the application of different culture systems for cultivation of shoot biomass and maximization of biologically active bacoside biosynthesis in this medicinally important plant. Shoot cultures of Bacopa were cultivated in two different modified benchtop bioreactors: glass bottle bioreactor and balloon type bubble bioreactor and compared with those grown in traditional Erlenmeyer agitated flask. The shoots cultivated in the balloon type bubble bioreactor system showed excellent growth (growth index 796.47 ± 17.27 fresh weight and 395.55 ± 7.55 dry weight) as compared to glass bottle bioreactor system (growth index 488.17 ± 14.4 fresh weight and 327.79 ± 6.64 dry weight) and agitated flask (growth index 363.43 ± 11 fresh weight and 304.22 ± 6.76 dry weight). Furthermore, bacosides produced by shoot cultures cultivated in the balloon type bubble bioreactor (321.95 ± 17.14 mg/L) and glass bottle bioreactor (180.18 ± 6.25 mg/L) configurations were ～2.78 fold and ～1.55 fold higher than that recorded in agitated flask cultures (115.7 ± 3.84 mg/L). The balloon type bubble bioreactor system was found to be advantageous for enhancing B. monnieri shoot biomass and bacoside biosynthesis along with ensuring a successful protocol for continuous supply.     

Quantitative variation in seeds,seedling growth and biomass among Acacia senegal (L) Willd. provenances in Kenya

Conventionally, local seed sources are normally believed to perform better than introduced materials. However, studies show possibility of contrary results with many species such as Acacia senegal. The species is an economically and ecologically important tree of arid and semi‐arid lands of sub‐Saharan Africa. It produces gum arabic, used in land reclamation and agroforestry production. The species is however underutilized in Kenya due to lack of information on growth performance of different seed sources. Glasshouse provenance trial using seeds and soils from seven provenances in Kenya were used to evaluate interactions between seed sources and soils on growth and biomass. Seedling growth was assessed for 12 weeks in a randomized complete block design. Seed length, width, thickness and weight were measured. Seedlings height, root collar diameter, root dry weight, shoot dry weight and biomass were assessed and data subjected to univariate and multivariate analyses. No significant interaction between seed provenance and soils were evident; however, some provenances performed better across all the soils. Significant heritability and relationship between growth and environmental factors are reported. Overall, Ntumburi and Ngarendare provenances showed superior growth and plasticity. These provenances can be used tentatively as seed sources; however, field trials are recommended.     

Tree dimensions: Maximizing the rate of height growth in dense stands

Summary To determine the effect of tree dimensions on the rate of height growth a model was constructed relating tree weight to total height and R, the ratio of crown weight to trunk weight. The model is based on the assumption that the trunk buckling safety factor is constant. If trees also maintain a constant R as they grow then the rate of height growth is maximized by R=0.17. In addition, the height growth rate increases as the buckling safety factor decreases. These predictions of optimal form for height growth are appropriate for shade intolerant, successional species growing in dense stands. Dimensional measurements of self thinning Populus tremuloides indicate near optimal dimensions for height growth. Trees ranging from 7 to 19 m in height had trunks which were only 50% thicker than the minimum required to prevent them from buckling under their own weight, and had a mean R of 0.13. This ratio of crown weight to trunk weight is significantly lower than the optimal value, but the predicted height growth rate for R=0.13 is 99% of that predicted for R=0.17.     

Age and growth of Alburnus tarichi (Güldenstädt, 1814): an endemic fish species of Lake Van (Turkey)

In total, 240 tarek, Alburnus tarichi, specimens were caught throughout February 2008 in Lake Van, Turkey, a lake with highly salty‐alkaline conditions. Ages, lengths and weights of A. tarichi were determined to estimate length–weight relationships and age composition. Otolith dimensions were also determined. Female : male ratio was 1.47 : 1. Fork length and total weight of specimens ranged from 14.3 to 19.2 cm and 45.76 to 99.63 g, respectively. Maximum age observed was 6 years. Length–weight relationships were calculated for female, male and combined sexes as, W = 0.057FL^2.582W = 0.102FL^2.513 W = 0.074FL^2.544, respectively. Concerning types of growth, negative allometric growth (b < 3) was observed for all tarek specimens. The lagenar otolith was large and flat and marks on otoliths were typically clear, consistent and easy to interpret. Mean otolith length, breadth and weight were determined as 2.592 mm, 2.381 mm, 0.0026 g, respectively. While the otolith weight displayed a curvilinear relationship with the fork length, otolith length and breadth were linearly related to the fork length by height correlation coefficients.     

Inter- and intraspecific diversity of ontogeny and fecundity patterns in relation to reproductive strategy choice in Myomorpha (Rodentia: Calomyscidae,Cricetidae, Muridae)

Studying the life history of various organisms is essential for ecological and evolutionary inferences. However, publications regarding models of evolutionary shifts to either r- or K-reproductive strategies are scarce. Here, the combined original and previously published data on reproduction and development of Goodwin’s brush-tailed mouse (Calomyscus elburzensis), golden hamster (Mesocricetus auratus), and house mouse (Mus musculus) were compared. An adult male and female in estrous state (from each species) were coupled with each other for a night and embryos were harvested at embryonic days (E) 10–17 from pregnant females. The mean gestation period in Goodwin’s brush-tailed mouse was 31.5?±?2.1 days; growth was rapid at the first half of this period and after that it was reduced by half. During the postnatal period, growth was rapid up to weaning, but after day 35, the rate of growth decreased abruptly. Growth rate of head and body length was very rapid prior to weaning (PN35) in comparison with weight but the rates of the two characters were inversed following weaning. Totally, weight gain was more dynamic in rate, as compared with head and body length, up to adultness. For golden hamster and house mouse, gestation period was 15.6?±?0.8 and 20.8?±?0.8 days, respectively. Growth was slow during approximately the first half of the gestation period in both species but increased during the second half. During postnatal period in golden hamster, growth rate of head and body length was rapid both before and after weaning as compared with that of weight. However, head and body length showed a stable rate of growth before and after weaning (around PN15), but for body weight, the growth rate was slightly faster after weaning. Similarly, changes in head and body length in house mouse were rapid both before and after weaning (PN16) as compared with that of weight. Since approximately two-fold increases were observed in the growth rates of weight and head and body length in the second stage of postnatal development (PN16-adult) compared with the rates during the first stage (PN0-PN16), both showed dynamic changes during the postnatal development in this species. Typically, r-strategic house mouse appeared to be more similar in early morphological development to comparatively K-strategic Goodwin’s brush-tailed mouse, than to comparatively r-strategic golden hamster. Nevertheless, growth rate and pattern were different in the three species after birth. Hence, results showed that peculiarities of association between an ontogenetic pattern and a tendency in reproductive strategy can differ in diverse groups of myomorph rodents.

     

The effects of Cercospora leaf disease on the growth of groundnuts (Arachis hypogaea) in Nigeria

Three experiments with five alternately-branched and one sequentially-branched cultivar of groundnuts are described. Spraying to control Cercospora leaf spot disease doubled the leaf area duration and increased the total weight of a plant by about 65 %. Spraying increased the weight of kernels per plant but in the alternately-branched cultivars also increased the weight of stem and leaves. The proportion of the total dry weight in the kernels in the alternate cultivars was hardly changed by spraying. The sequentially-branched cultivar gave the same increase in total dry weight when sprayed but spraying resulted in a larger increase in the dry weight of kernels. The sequentially-branched cultivar, with few initials for vegetative growth, did not give the same increase in leaf growth.     

Biological evaluation of frozen zooplankton as food for milkfish (Cbanoschanos) fry

Milkfish fry with an average standard length and weight of 13.88 mm and 3.95 mg, respectively, were reared for 30 days using live and frozen Moina macrocopa and Brachionusplicatilis at feeding densities of 10–20 individuals per ml. Growth, survival and yield were used as indicators of the overall performances of the various treatment groups. Fry fed live M. macrocopa showed gains (both length and weight), growth and survival rates and yields significantly higher than fry fed with other treatment groups (P < 0.05). However, significant reductions in growth and survival rates resulted when fry were fed frozen M. macrocopa. On the other hand, there were no significant differences in growth and survival rates (P < 0.05) in fry fed live or frozen B. plicatilis. The results of the current study showed that although milkfish fry could be grown successfully using B. plicatilis, feeding with live Moina significantly improved growth, survival rate and yield (P lt; 0.05). Frozen Moina was found to be unsuitable as a feed for rearing milkfish fry because it reduced growth rates and increased mortality. Comparisons between live and frozen rotifers have proven the suitability of frozen rotifers as feed for rearing milkfish fry. By freezing surplus rotifers this would permit short term storage in anticipation of high hatchery demand and overcome any unpredictable failures with live cultures.     

Growth of Tubifex tubifex Müller (Oligochaeta,Tubificidae) under Various Trophic Conditions

Growth of Tubifex tubifex on highly caloric activated sludge and poor in organic matter natural silt was experimentally studied. The relationship between oxygen consumption rate, weight, and caloric value of T. tubifex body in culture on activated sludge was determined to calculate the growth efficiency (K₂ = P/P + R). The growth rate has been determined, and models of T. tubifex growth are given under various trophic conditions conforming to results of the experiment. Somatic growth, generative growth and life span of this species were compared on the basis of the experiments and literature. Acceleration of growth and prolongation of life under conditions of caloric food and delay of these processes in silt poor in organic matter have been established and measured. T. tubifex was found to have advantages as compared to other tubificid species in response to increasing amounts of nutrient food in waters polluted by organic matter and, therefore, to produce abundant populations under these conditions.     

Effects of Castration on Growth and Reproduction of Helisoma duryi (Mollusca: Pulmonata)

Summary

Castration of Helisoma duryi disturbs the balance between growth and reproduction in favour of growth, as is evidenced by the stimulation of body and shell growth and reduction in egg mass production when compared with sham operated controls. Female accessory sex organ wet weight is increased in castrated and virgin snails. Male accessory sex organ wet weight is unaffected and female accessory sex organ wet weight is reduced by dorsal body ablation, suggesting that growth of differentiated female accessory sex organs is stimulated by the endocrine dorsal bodies. Albumen gland synthetic activity is inhibited in the absence of a functioning gonad. This inhibition may be due partly to the accumulation of secretory products within the glands and partly to the inactivation of the endocrine dorsal bodies and neurosecretory caudodorsal cells in the cerebral ganglia. The circulating levels of the vitellogenic protein ferritin are reduced by castration, and increased by injection and implantation of active gonadal tissue into castrates. This may be due to an indirect effect of gonadal factor (s) on the extragonadal synthesis of ferritin.     

Effect of starvation and re‐feeding on growth performance and content of plasma lipids,glucose and insulin in cultured juvenile Persian sturgeon (Acipenser persicus Borodin, 1897)

The effect of starvation and subsequent re‐feeding to satiation on compensatory growth performance, insulin and blood serum values were investigated in juvenile Persian sturgeon (Acipencer persicus) with an average weight 108.04 ± 0.28 g (mean ± SEM) and in the same rearing condition over an 8‐week period. Sturgeons were allocated to one of five feeding treatments: controls (C, continuous feeding), W1 (1 week starvation), W2 (2 weeks starvation), W3 (3 weeks starvation) and W4 (4 weeks starvation), followed by a single 4 weeks of re‐feeding to satiation. Changes in growth performance and blood serum indices were examined at the end of weeks 4 and 8. Body weight, specific growth rate (SGR), condition factor (CF) and weight gain were determined to have significantly decreased during starvation. Fish starved for 1 week reached the same weight as the control fish after re‐feeding for 4 weeks, indicating that complete compensatory growth occurred. Although the specific growth rate in W2, W3 and W4 fish was greater than that in the control fish after re‐feeding, W2, W3 and W4 fish did not reach the same body weight as control fish at the end of re‐feeding period, and showed partial compensation only. Blood plasma, glucose and insulin concentrations did not change significantly during starvation and re‐feeding (P > 0.05). This suggests that sturgeon are able to maintain glycaemia during starvation, probably due to their non‐carbohydrate dietary source. Plasma total lipid and triglyceride levels increased in starvation treatments, whereas the increases were significant only in W3 treatment (P < 0.05). After a 4‐week re‐feeding period, their levels decreased in comparison to the starvation periods. Increases in plasma total lipid and triglyceride levels appear to be due to their roles as preferred nutrients for mobilization in Persian sturgeon and the magnitude and duration of compensatory growth depended on the length of food deprivation.