Feeding habits of invasive American mink (Neovison vison) in northern Germany—potential implications for fishery and waterfowl

In order to collect ecological data of invasive American mink (Neovison vison) at a fishpond area in northeastern Germany, we conducted a telemetry study in which 14 mink were radio-tracked. During this project, 2,502 scats from radio-tracked individuals were collected in the period from October 2003 to October 2005. Investigated mink principally prey on fish, small mammals and birds (eggs inclusive), whereas amphibians, reptiles and invertebrates were caught infrequently. Analysing mink scats of different seasons, we found significant seasonal variations of diet composition. In spring, fish, mammals and birds were hunted in similar amounts. During summer, birds made up the main part of the diet followed by mammals. In autumn, the proportion of birds in the mink diet decreased, whereas fish gained in importance. This trend continued during the winter period, when mink preyed almost exclusively on fish. Amphibians, crustaceans, insects, molluscs and reptiles were found only occasionally in scat samples. Among birds, the mink preyed mainly on the Eurasian Coot (Fulica atra) followed by the Mallard (Anas platyrhynchos). Mammalian prey was clearly dominated by the water vole (Arvicola terrestris) and among fish, mink hunted especially perch (Perca fluviatilis), roach (Rutilus rutilus) and carp (Cyprinus carpio). Results clearly demonstrate that mink is an opportunistic predator, which hunts its prey according to availability and vulnerability, respectively. Despite the high portions of fish in their autumn and winter diet, the economic damage caused by mink seems to be negligible. However, high predation rates on birds during the breeding season indicate a potential negative impact of mink on waterfowl.     

Sequencing and gene expression of the porcine ITIH SSC13 cluster and its effect on litter size in an Iberian × Meishan F2 population

The aim of the present study was to identify polymorphisms and to analyze endometrial gene expression of the porcine SSC13 ITIH cluster that could explain differences in prolificacy of 255 F(2) sows derived from an Iberian (Ib)×Meishan (Me) intercross in which QTL for the number of piglets born alive (NBA) and total number of piglets born (TNB) were previously detected on this chromosome. Sequencing of ITIH-1, -3, and -4 mRNAs was done and several polymorphisms segregating within the Ib×Me population were found in all three genes. Significant associations with NBA were found for two SNPs from ITIH-1, four from ITIH-3, and four SNPs from ITIH-4 (p<0.05). Haplotypes for the significant SNPs were calculated by segregation analysis and a marker assisted association test indicated that the alleles coming from the Meishan breed had a favorable effect on NBA for all three genes. Interestingly, some of the significant SNPs were located within the von Willebrand domain of the ITIH proteins, the binding site of molecules essential for the synthesis of the extracellular matrix during cumulus expansion. Gene expression analyses also revealed differences in the expression level of the ITIH-3 gene regarding the prolificacy performance (high or low) and the uterus sample (apical or basal).     

How does co-product handling affect the carbon footprint of milk? Case study of milk production in New Zealand and Sweden

Purpose  

This paper investigates different methodologies of handling co-products in life cycle assessment (LCA) or carbon footprint (CF) studies. Co-product handling can have a significant effect on final LCA/CF results, and although there are guidelines on the preferred order for different methods for handling co-products, no agreed understanding on applicable methods is available. In the present study, the greenhouse gases (GHG) associated with the production of 1 kg of energy-corrected milk (ECM) at farm gate is investigated considering co-product handling.     

Apoplastic and cytosolic expression of full‐size antibodies and antibody fragments in Nicotiana tabacum

We compared the expression of a functional recombinant TMVspecific fullsize antibody (rAb29) in both the apoplast and cytosol of tobacco plants and a single chain antibody fragment (scFv29), derived from rAb29, was expressed in the cytosol. Cloned heavy and light chain cDNAs of fullsize rAb29, which binds to TMV coat protein monomers, were integrated into the plant expression vector pSS. The fullsize rAb29 was expressed in the cytosol and targeted to the apoplast by including the original murine antibody leader sequences. Levels of functional fullsize rAb29 expression were high in the apoplast (up to 8.5g per gram leaf tissue), whereas cytosolic expression was low or at the ELISA detection limit. Sequences of the variable domains of rAb29 light and heavy chain were used to generate the single chain antibody scFv29, which was expressed in the periplasmic space of E.coli and showed the same binding specificity as fullsize rAb29. In addition, scFv29 was functionally expressed in the cytosol of tobacco plants and plant derived scFv29 maintained same binding specificity to TMVcoat protein monomers as rAb29.     

Latitudinal variation in litter size of polar bears: ecology or methodology?

I used data reported in the scientific literature to examine latitudinal variation in litter size of polar bears in 18 different populations. No relationship was found between litter size and latitude using non-weighted regression. Regression weighted by sample size indicated a negative relationship with latitude. However, sampling biases caused by latitudinal differences in the timing of sampling and cub mortality after den emergence could produce a latitudinal cline. Stratifying analyses by sampling area, at dens or away from dens, revealed no latitudinal trend in litter size. Observed differences in litter size among populations may result from variation in demography and ecosystem productivity that is not simply related to latitude. I conclude that available data do not provide support for a biologically significant latitudinal cline in polar bear litter size. Accepted: 25 May 1999     

Polymorphism of β-lacto globulin gene in Indian goats and its effect on milk yield

Polymorphism in the beta-LG gene in the Indian goat was investigated by the SDS-PAGE and PCR-RFLP method. SDS-PAGE was carried out in 1098 samples belonging to 8 different breeds of Indian goats. The electrophoretic pattern in the beta-LG locus showed the presence of AA and AB genotypes with frequencies of 0.81 and 0.19, 0.89 and 0.11, 0.50 and 0.50, 0.80 and 0.20, 0.84 and 0.16, 1.00 and 0.00, 0.98 and 0.02 and 0.950 and 0.050 in Jamunapari, Barbari, Marwari, Sirohi, Jakhrana, Beetal, Local UP and Local MP goats, respectively. A total of 358 individuals belonging to 13 different genetic groups were analyzed by the PCR-RFLP method. The amplified product was observed as 426 bp and the restriction digestion with SacII revealed three genotypes, namely S1S1, S1S2 and S2S2 at the beta-LG locus. The frequency of the S2S2 genotype ranged from 0.42 to 1.00 in the population. An analysis was carried out in Jamunapari and Barbari goats to observe the effect of the beta-LG genotype on 90-day milk yield. Least squares analysis of data showed that beta-LG AA animals had higher milk yield than the beta-LG AB genotype in both breeds (P < 0.01).     

Effect of polymorphisms in the CSN3 (κ-casein) gene on milk production traits in Chinese Holstein Cattle

This study was designed to evaluate significant associations between single nucleotide polymorphisms (SNPs) and milk composition and milk production traits in Chinese Holstein cows. Six SNPs were identified in the κ-casein gene using pooled DNA sequencing. The identified SNPs were genotyped by Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) methods from 507 individuals. Out of six, we identified three non-synonymous SNPs (g.10888T>C, g.10924C>A and g.10944A>G) that changed in the protein product. SIFT (Sorting_Intolerant_From_Tolerant) prediction score (0.01) demonstrated that protein changed Isoleucine > Threonine (g.10888T>C) will affect the phenotypes. Significant associations between identified SNPs and three yield traits (milk, protein and fat) and two composition traits (fat and protein percentages) were found whereas it did not reach significance for fat percentage in haplotypes association. Importantly, the significant SNPs in our results showed a large proportion of the phenotypic variation of milk protein yield and concentration. Our results suggest that CSN3 is an important candidate gene that influences milk production traits, and identified polymorphisms and haplotypes could be used as a genetic marker in programs of marker-assisted selection for the genetic improvement of milk production traits in dairy cattle.     

Latitudinal and seasonal patterns in clutch size of some single‐brooded British birds

Capsule Daylength, rather than latitude, was found to be an important determinant of variation in clutch size.

Aims To describe the nature of spatial and temporal variation in clutch size, and explore the ecological correlates of these patterns.

Methods We tested the prediction that seasonal declines in clutch size will be greater at higher latitudes. The environmental variables focused on were the influence of daylength, plant productivity, seasonality (i.e. Ashmole's hypothesis) and physiological mechanisms that relate clutch size to ambient temperature. We used data from 1980 to 2003 on spatial variation in clutch size across Britain for single‐brooded species, in which clutch size can be taken as a measure of annual reproductive investment. We included all seven species, from five families, with sufficient data in the British Trust for Ornithology's Nest Record Scheme.

Results There are strong seasonal declines in clutch size but little evidence for latitudinal gradients in clutch size or in latitudinal gradients in the rate of seasonal clutch size decline. Of the environmental variables investigated, daylength had the most marked effect on clutch size; this was positive in diurnal species and negative in the one nocturnal species.

Conclusions Although this study was confined to a relatively small latitudinal range of 8°, we found marked latitudinal gradients in a number of factors thought to drive spatial patterns in clutch size. Moreover, such variation is of sufficient magnitude to generate spatial patterns in other ecological variables in Britain. There is thus no simple explanation for the lack of a latitudinal gradient in clutch size. The results concerning daylength indicate that the time available for foraging is an important determinant of variation in clutch size.     

Parasiticidal effect of 16α-bromoepiandrosterone (EpiBr) in amoebiasis and cysticercosis

The effect of the dehydroepiandrosterone analog 16α-bromoepiandrosterone (EpiBr) was tested on the tapeworm Taenia crassiceps and the protist Entamoeba histolytica, both in vivo and in vitro. Administration of EpiBr prior to infection with cysticerci in mice reduced the parasite load by 50% compared with controls. EpiBr treatment induced 20% reduction on the development of amoebic liver abscesses in hamsters. In vitro treatment of T. crassiceps and E. histolytica cultures with EpiBr, reduced reproduction, motility and viability in a dose- and time-dependent fashion. These results leave open the possibility of assessing the potential of this hormonal analog as a possible anti-parasite drug, including cysticercosis and amoebiasis.     

Effects of topographic position,leaf litter and seed size on seedling demography in a semi-deciduous tropical forest in Panamá

This study examined whether topography-induced gradients in water potential and leaf litter depth contribute to species coexistence in tropical forests through species-specific effects on seedling emergence and mortality. Seedling emergence and mortality were followed for a period of 12 months in 36 (1 × 2 m) plots on Barro Colorado Island (BCI), Panamá. Plots with and without litter were distributed on slope and plateau sites in three catchments. In the absence of manipulations, the lower litter depth on slopes resulted in approximately four times as many emergent seedlings than on plateau sites. However, litter depth had little effect on seedling community composition. By the end of the first dry-season, post-emergence, there were no significant differences in surviving seedling numbers between any treatments. There were differences in the emergent seedling community between slope and plateau sites within the same catchment as well as differences in composition between catchments, suggesting that both niche partitioning and dispersal limitation might play a role in structuring seedling community composition. During the wet-season seedling mortality was highest on slope sites although this pattern was reversed during the dry-season. In both seasons mortality was higher for small-seeded species. These results demonstrate that gradients in water potential related to topography impact on patterns of seedling emergence and mortality although processes in the first year after emergence may be insufficient to explain observed habitat preferences of adult plants.     

Polymorphism of 5′ regulatory region of ovine FSHR gene and its association with litter size in Small Tail Han sheep

Single nucleotide polymorphisms of 5?? regulatory region of follicle-stimulating hormone receptor (FSHR) gene were detected in two high prolificacy sheep breeds (Small Tail Han and Hu sheep) and two low prolificacy sheep breeds (Corriedale and Chinese Merino sheep) by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). The results indicated that there were three genotypes (AA, AB and BB) detected by primer 1 in Hu sheep while only one genotype (AA) in other three sheep breeds, and frequencies of AA, AB and BB genotypes in Hu sheep were 0.700, 0.225 and 0.075, respectively. There were three genotypes (EE, EF and EG) detected by primer 3 in Small Tail Han sheep while only EE genotype occurred in other three sheep breeds, and frequencies of EE, EF and EG genotypes in Small Tail Han sheep were 0.775, 0.200 and 0.025, respectively. No polymorphism was detected in four sheep breeds by primer 2 and primer 4. The sequencing results showed that there were two nucleotide mutations (g. ?681T>C and g. ?629C>T) in genotype BB compared with AA for primer 1. As for primer 3, two mutations (g. ?197G>A and g. ?98T>C) in genotype EF compared with EE and two mutations (g. ?200G>A and g. ?197G>A) in genotype EG compared with EE. The heterozygous ewes with EG or EF had 0.89 (P?<?0.05) or 0.42 (P?<?0.05) lambs more than homozygous ewes (EE genotype) in Small Tail Han sheep, respectively, while there was no significant difference on litter size between EG and EF ewes.     

Is there a relationship between prion protein genotype and ovulation rate and litter size in sheep?

The identification of an association between polymorphisms of the prion protein (PrP) gene and susceptibility to scrapie has enabled the development of breeding programmes to increase natural resistance to scrapie. It is, however, imperative to identify if such selection would affect important reproduction and production traits. The objective of this study was to determine if there is a relationship between polymorphisms at codons 136, 154 and 171 of the PrP gene and ovulation rate or litter size in sheep. Data were collected from a mixed-aged flock of Belclare ewes, over a 9-year period. Ovulation rate was determined annually using laparoscopy by counting the number of corpora lutea at each of two consecutive oestrous cycles, one immediately before and one after mating (2418 records from 366 ewes). Litter size was recorded at parturition (875 records from 353 ewes). The five common PrP alleles were present in the population and 14 PrP genotypes were represented among the animals studied. There was no significant overall effect of PrP genotype on ovulation rate or litter size and pairwise comparisons among genotypes did not reveal any significant differences for either trait. These data suggest that breeding programmes based on selection for specific polymorphisms of the PrP gene will not influence ovulation rate or litter size, at least in the breed studied.     

Large litter size increases maternal energy intake but has no effect on UCP1 content and serum-leptin concentrations in lactating Brandt’s voles (<Emphasis Type="Italic">Lasiopodomys brandtii</Emphasis>)

Lactation is the most energetically demanding period in the female mammal's life. We measured maternal energy intake, uncoupling protein 1 (UCP1) content in brown adipose tissue (BAT), serum-leptin concentration, and litter growth in lactating Brandt's voles (Lasiopodomys brandtii) with different litter sizes. Litter mass was positively related to litter size but there was no difference in pup mass at birth. Maternal gross energy intake at peak lactation was positively correlated with litter size and litter mass. Maternal resting metabolic rate (RMR) was positively correlated with litter mass, but not with litter size. No significant differences were detected in body-fat mass, serum-leptin concentration, or UCP1 in lactating voles with different litter sizes. Serum-leptin concentration was negatively correlated with energy intake during lactation. Our data did not support the hypothesis that there is a trade-off in energy allocation between maternal maintenance and offspring growth in lactating Brandt's voles, but support the idea that if the mothers with ten pups should have less energy available for their maintenance than mothers raising fewer pups. Also, leptin is probably not the only factor that induces the high energy intake in mothers with large litter sizes, although it was involved in the regulation of energy intake during lactation.     

Do mothers prefer helpers or smaller litters? Birth sex ratio and litter size adjustment in cotton-top tamarins (Saguinus oedipus)

Sex allocation theory has been a remarkably productive field in behavioral ecology with empirical evidence regularly supporting quantitative theoretical predictions. Across mammals in general and primates in particular, however, support for the various hypotheses has been more equivocal. Population‐level sex ratio biases have often been interpreted as supportive, but evidence for small‐scale facultative adjustment has rarely been found. The helper repayment (HR) also named the local resource enhancement (LRE) hypothesis predicts that, in cooperatively breeding species, mothers invest more in the sex which assists with rearing future offspring and that this bias will be more pronounced in mothers who require extra assistance (i.e., due to inexperience or a lack of available alloparents). We tested these hypotheses in captive cotton‐top tamarins (Saguinus oedipus) utilizing the international studbook and birth records obtained through a questionnaire from ISIS‐registered institutions. Infant sex, litter size, mother's age, parity, and group composition (presence of nonreproductive subordinate males and females) were determined from these records. The HR hypothesis was supported over the entire population, which was significantly biased toward males (the “helpful” sex). We found little support for helper repayment at the individual level, as primiparous females and those in groups without alloparents did not exhibit more extreme tendencies to produce male infants. Primiparous females were, however, more likely to produce singleton litters. Singleton births were more likely to be male, which suggests that there may be an interaction between litter size adjustment and sex allocation. This may be interpreted as supportive of the HR hypothesis, but alternative explanations at both the proximate and ultimate levels are possible. These possibilities warrant further consideration when attempting to understand the ambiguous results of primate sex ratio studies so far.     

Iodine concentration of milk in a dose–response study with dairy cows and implications for consumer iodine intake

Most feed is poor in iodine and iodine supplementation of cow's diets must guarantee milk iodine concentrations for humans that contribute to prevention of the deficiency and minimize the risk of exceeding an upper limit of iodine intake. Five Holstein cows were fed four iodine doses (via Ca(ΙO₃)₂·6H₂O). In four sequential 14-d periods, doses of 0.2 (basal diet), 1.3, 5.1, and 10.1 mg iodine kg^?1 diet dry matter (DM) were administered. Samples of milk were collected during each period; blood was also sampled from each cow for each iodine dosage. In an 18-d depletion period, a non-supplemented diet was provided. Iodine was determined by inductively coupled plasma-mass spectrometry. The iodine content of milk and serum reflected the iodine dosages in feed significantly. The levels for the four doses tested in milk were 101±32, 343±109, 1215±222, and 2762±852 μg iodine kg^?1. The total amount of iodine in milk per day was 30–40% of ingested supplemental iodine. Omitting additional iodine resulted in a short-term reduction of serum and milk iodine following an exponential decay function. The iodine supplementation of 0.5–1.5 mg kg^?1 diet DM represents the requirement of the cow, resulting in 100–300 μg iodine L^?1 milk, which optimally contributes to human supply. The maximum dietary levels of former and present EU legislations (10 and 5 mg iodine kg^?1 cow feed) increase the risk of iodine excess in humans.     

Kinetics of β-N-methylamino-L-alanine (BMAA) and 2, 4-diaminobutyric acid (DAB) production by diatoms: the effect of nitrogen

The neurotoxins β-N-methylamino-L-alanine (BMAA) and 2,4-diaminobutyric acid (DAB) are produced by cyanobacteria, diatoms and dinoflagellates and have been detected in seafood worldwide. Our present knowledge of their metabolism or biosynthesis is limited. In this study, the production of BMAA and DAB as a function of time was monitored in five strains representing four species of diatoms, i.e. Phaeodactylum tricornutum, Thalassiosira weissflogii, Thalassiosira pseudonana and Navicula pelliculosa, previously identified as BMAA and DAB producers. Subsequently, three strains were selected and exposed to three nitrogen treatments – starvation, control (the standard concentration in f/2 medium) and enrichment, because BMAA metabolism has been suggested to be closely associated with cellular nitrogen metabolism in both cyanobacteria and diatoms. Chlorophyll a and total protein concentrations were also determined. Our results indicate that BMAA and DAB production in diatoms is species- and strain-specific. However, production might also be affected by stress, particularly as related to nitrogen starvation and cell density. Furthermore, this study shows a significant correlation between the production of the two neurotoxins which might further suggest common steps in the metabolic pathways.     

Analysis of waving and sound‐production display in the ghost crab,Ocypode stimpsoni

The ghost crab Ocypode stimpsoni displays waving and sound production. Sounds are produced by thumping the sand substratum with the major cheliped, and two types of sounds can be discriminated; one with a low frequency of about 12 Hz, called rapping, and another with a higher frequency (about double), called quivering. In our observations, a sequence of waving and sound emission would sometimes terminate abruptly, or appear as independent components but the component order never changed. The most frequently observed patterns were “waving with rapping and quivering”;, “waving with quivering”; and “quivering only”; quivering sounds being involved in more than 80% displays. Quivering sometimes occurred immediately after crabs emerged from the burrow, or when they returned to the entrance after discarding an excavated sand mass. The occurrence frequency of waving and sounds, the wave amplitude, and the frequency of the sound increased when other crabs approached.