Shell Breakage Research Articles

Radio frequency plus heat for in-shell egg pasteurization

Less than 3 % of the eggs in the United States are sold pasteurized because of the long thermal process (~ 60 min). However, this represents a food safety risk because of the possible presence of Salmonella spp. inside the egg. This research studied the inactivation of S. typhimurium in in-shell eggs using the novel technology radio frequency (RF) to enhance their food safety, evaluating quality, presence of sub-lethally injured cells (SICs), and cell recovery (7 °C). Eggs were inoculated inside with S. typhimurium (105 CFU/egg) and processed with RF (40.68 MHz, 35 W, 4.5 min) followed by hot water spray (H, 56.7 °C, 20 min). The studied quality attributes were yolk color, Haugh unit, yolk index, shell breakage strength, yolk and albumen pH, and albumen degradation. ANOVA one–way was used to find significant differences (α = 0.05). RF plus heat can pasteurize the eggs after 24.5 min (5-log reduction). No SICs were detected in any of the samples, and cells did not recover after five days of storage (Limit of detection <1 log CFU/g). Most quality attributes were like the control eggs. Albumen degradation showed a significant difference (p < 0.05) after processing. RF represents a potential option to ensure the safety of in-shell eggs, preserving their quality. Industry relevanceMost in-shell eggs are sold unpasteurized worldwide with the potential risk of Salmonella spp. The conventional pasteurization process is a lengthy intervention that adds cost to the product and can damage the quality of eggs. Radio frequency plus heat pasteurization offers an alternative to pasteurizing in-shell eggs with a volumetric heating process that inactivates Salmonella cells inside the eggs and has minor effects on the quality of eggs. This technology is a novel option for the egg industry, providing high-quality and reasonably priced safe eggs.

A Two-Step Intermolecular Interaction Of Molecular Macroions With Multivalent Counterions.

Macroion-counterion interaction is essential for regulating the solution behaviors of hydrophilic macroions, as simple models for polyelectrolytes. Here, we explore the interaction between uranyl peroxide molecular cluster Li68K12(OH)20[UO2(O2)OH]60 (U60) and multivalent counterions. Different from interaction with monovalent counterions that shows a simple one-step process, isothermal titration calorimetry, combined with light/X-ray scattering measurements and electron microscopy, confirm a two-step process for their interaction with multivalent counterions: an ion-pairing between U60 and the counterion with partial breakage of hydration shells followed by strong U60-U60 attraction, leading to the formation of large nanosheets with severe breakage and reconstruction of hydration shells. The detailed studies on macroion-counterion interaction can be nicely correlated to the microscopic (self-assembly) and macroscopic (gelation or phase separation) phase transitions in the dilute U60 aqueous solutions induced by multivalent counterions.

Upconverting Nanoparticles Coated with Light-Breakable Mesoporous Silica for NIR-Triggered Release of Hydrophobic Molecules.

Upconverting nanoparticles (UCNPs) doped with Yb3+ and Tm3+ are near-infrared (NIR) to ultraviolet (UV) transducers that can be used for NIR-controlled drug delivery. However, due to the low quantum yield of upconversion, high laser powers and long irradiation times are required to trigger this drug release. In this work, we report the one-step synthesis of a nanocomposite consisting of a LiYbF4:Tm3+@LiYF4 UCNP coated with mesoporous UV-breakable organosilica shells of various thicknesses. We demonstrate that a thin shell accelerates the breakage of the shell at 1 W/cm2 NIR light exposure, a laser power up to 9 times lower than that of conventional systems. When the mesopores are loaded with hydrophobic vitamin D3 precursor 7-dehydrocholesterol (7-DH), shell breakage results in subsequent cargo release. Its minimal toxicity in HeLa cells and successful internalization into the cell cytoplasm demonstrate its biocompatibility and potential application in biological systems. The tunability of this system due to its simple, one-step synthesis process and its ability to operate at low laser powers opens up avenues in UCNP-powered NIR-triggered drug delivery toward a more scalable, flexible, and ultimately translational option.

Mycoplasma synoviae LP78 is a fibronectin/plasminogen binding protein, putative adhesion, and potential diagnostic antigen.

Mycoplasma synoviae (M. synoviae) is one of the major poultry pathogens causing infectious synovitis, airsacculitis, a high incidence of shell breakage, and egg production loss. However, the pathogenesis of M. synoviae remains unclear. Adhesion of mycoplasmas to host cells is a crucial step in infection and colonization. The purpose of this study was to determine the adhesive function of a putative P80 family lipoprotein (LP78) and evaluate its application in the detection of antibodies against M. synoviae. Recombinant LP78 (rLP78) was expressed in the supernatant component of Escherichia coli and mouse anti-rLP78 serum was prepared. Bioinformatic analysis and western blotting results revealed that LP78 was conservative among M. synoviae strains. It was distributed not only in the cytoplasm but also on the membrane of M. synoviae through western blotting and indirect immunofluorescence (IFA). The adherence of M. synoviae to DF-1 cells was significantly inhibited by mouse anti-rLP78 serum (p < 0.01). IFA revealed that rLP78 adhered to DF-1 cells, and this adherence was prevented by mouse anti-rLP78 serum. Furthermore, rLP78 was found to bind to the DF-1 cells membrane proteins in a dose-dependent manner by enzyme-linked immunosorbent assay (ELISA). Screening of DF-1 cells membrane proteins by western blotting showed that proteins with molecular weight of 35-40 kDa and 55-70 kDa bound to rLP78. Moreover, rLP78 was identified to be a fibronectin/plasminogen binding protein. The sensitivity and specificity of rLP78-based iELISA were 85.7 and 94.1%, respectively. The maximum dilution of positive serum (HI titer, 1:128) detected via rLP78-based iELISA was 1:6,400, whereas that detected using a commercial ELISA kit was 1:12,800-1:25,600. Both rLP78-based iELISA and the commercial ELISA kit detected seroconversion after 7 days of challenge and immunization. No cross-reactivity with positive sera against other avian pathogens was observed in rLP78-based iELISA. Collectively, these results indicate that LP78 is a fibronectin/plasminogen-binding adhesion protein of M. synoviae and a potential diagnostic antigen. The present study will facilitate a better understanding of the pathogenesis of M. synoviae and the development of new diagnostic.

Ca2+ addition facilitates the shell repair with eggs production of Pomacea canaliculata through biomineralization and food intaking regulation

Pomacea canaliculata was by far one of the most harmful invasive organisms in the world, causing serious harm to aquatic crops and ecosystem. Calcium carbonate is a common component of aquatic environment, which is important for the growth of Pomacea canaliculata. Therefore, the objective of this study was to investigate the response characteristics of P. canaliculata suffered shell breakage to the addition of calcium carbonate in water environment. In this experiment, we explored the effects of calcium carbonate addition on the P. canaliculata shell repair rate, food intake, egg production, shell strength, and calcium content through breaking the snails shell and the addition of calcium carbonate treatment. The results showed that snail broken-shell repaired mostly within 21 days. The snails experienced a significant increase in shell repair rates during earlier days of the treatment, especially for female snails. Food intake of snails exhibited different patterns when their shells were broken and calcium carbonate was added. Shell breakage treatment combined with calcium carbonate addition significantly increased the diameter of snail eggs compared with the control and the calcium carbonate addition treatment without shell-broken snail group. There was no significant difference in shell strength or calcium content of male snails between the treatments. The study suggests that P. canaliculata exhibits a sex-dependent response pattern when subjected to shell damage and calcium carbonate addition. The findings can provide some references to better understand the invasion mechanism and survival strategy of the P. canaliculata.

Experimental study on buckling behavior of composite cylindrical shells with and without circular holes under hydrostatic pressure

Composite materials have been widely used in the field of pressure shells for underwater vehicles due to their great potential. This paper presents an experimental study of composite cylindrical shells with and without the circular hole subjected to external hydrostatic pressure. The mechanical response of the composite cylindrical shells under external hydrostatic pressure is recorded by the strain acquisition system, and the buckling deformation process of the shells is also captured by the high-speed camera system. According to the experimental results, the entire compression process of the shell can be divided into three stages based on variations in strain. Based on the findings that buckling starts very early and accounts for about 35 % of the entire process, the concept of initial buckling pressure is proposed to distinguish the critical point of the shell transition from a stable state to an unstable state. It is found that the damage positions of the three shells all correspond to the troughs in the buckling waveform, and the final fiber breakage of the perforated shells with the reinforcements both occur near the reinforcement component. Finally, a comparative analysis of the strain response of the shell with the hole and the complete shell is carried out to explore their similarities and differences. The experimental results in this paper provide valuable information for the design of perforated composite pressure shells for underwater vehicles.

Influence and its Mechanism of Non-reactive Fillers on the Dispersion Characteristics of the Fragments from Charge Structures

With the diversified development of innovative warheads and the increasing threat of improvised explosive devices (IEDs), the charge structure filled with both explosives and non-reactive materials has attracted the attention of researchers, which is few studied. In order to obtain the fragmentation of the charge structure with part of the non-reactive filler, the X-ray radiography explosion experiment was carried out for an axisymmetric charge structure partially filled with nylon that serves as a typical non-reactive filler. The fragmentation and fragment dispersion characteristics of the charge structure were observed. Based on the results of X-ray experiments, the influence mechanism of shell breakage and fragment dispersion characteristics of the charge structure filled with non-reactive filler are analysed by using SPH numerical calculation method. The results show that the non-reactive filler will significantly affect the fragmentation of the shell and considerably reduce the fragment velocity of the fragments in the filling direction. However, the fragment dispersion direction of the charge structure is not affected by the non-reactive filler. The conclusions could be a foundation and reference for further research on new charge structures.

Study on the Mechanical Properties and the Way of Breaking the Shell of Fresh Camellia oleifera Fruit

In this study, based on the physical and mechanical parameters of Camellia oleifera, the mechanical model of Camellia oleifera was rebuilt and analysed to reveal the damage mechanism of fruit shell breakage. The results revealed that under the same conditions (e.g., axial loading form), the stress of the fruit uniformly diffused from the extrusion point to the periphery and depth, and the maximum equivalent stress was 9.4104 Mpa. While under radial loading, the stress of the fruit extended axially along the dorsal line of the tea seed, and the maximum equivalent stress was 6.9467 Mpa. The maximum stress under the two loading modes occurred at the joint between the middle column of the shell and the calyx. The increased loading displacement decreased the stress on the fruit, making it easier to break the shell of Camellia oleifera by radial extrusion. The results can serve as a reference for the development of different equipment to break the shell of the Camellia oleifera fruit.

Chitosan coatings and chitosan nanocomposite to enhance the storage stability of fresh eggs during storage

Bio-based coatings contribute to enhance the shell quality and maintain fresh eggs' quality consequently contributing to the reduction of food losses. Biopolymer chitosan with three different (1%, 4%, and 8%-w/w) concentrations and also chitosan-montmorillonite (MMT-1%) nanocomposites were used in the production of coatings to maintain the storability of fresh eggs (pH, Haugh Unit, Yolk Index, foaming power-RWC, shell breakage, and rheology) for 4 weeks storage (24°C). The coatings sealed the pores of the eggshell, so it reduced breakage, and the mass transfer and increases the storability of the eggshell. Haugh unit (HU) differences in significance were observed between uncoated and coated fresh eggs after 2 weeks. The HU of eggs with chitosan-MMT (58.2) and chitosan 8% (58.1) had a significantly higher HU than control (37.3) and chitosan-1% (54.5) after 4 weeks of storage. This study showed that chitosan coatings acted as a protective barrier for maintaining the interior quality of the fresh eggs. The RWC for the chitosan-coated eggs was higher than the uncoated ones at all storage periods. Eggs coated with chitosan-4, chitosan-8%, and MMT had lower yolk pH values significantly than those control after 2 weeks and chitosan 1% after 2 weeks. A significant difference, among all chitosan-coated ones after 4 weeks of storage, was not found. The results underline that the chitosan coatings preserved the RWC of eggs and it is due to an efficient barrier property against the loss of CO2, avoiding changes in the pH of the egg albumen during storage. Novelty impact statement Coatings using chitosan-montmorillonite may help retail sectors in minimizing the economic losses due to breakage or cracks. Chitosan-montmorillonite coatings were efficient in minimizing the permeability of the shell by sealing eggshell pores. The storage stability of eggs was enhanced by bio-based coatings.

Design and development of a palm kernel nut cracking unit

The object of this research is the cracking of the nuts of oil palm (Elaesis guineensis). The oil palm tree is one of the greatest economic assets a nation can have, provided its importance is realized and fully harnessed. After the oil extraction of palm oil from the palm fruits, virtually all methods involved in palm kernel nut cracking both in traditional and small-scale exist in scattered or separate units of operations. Hence, this research focused on designing a palm nut kernel cracking unit incorporating a separator in form of a screen to separate cracked palm kernel nut shell from kernel. The result shows that there were significant difference (p≤0.05) among the moisture content of the palm nuts, shaft speed of the machine and weight (feed rate), having a significant difference between: – moisture content of the palm nut and the shaft speed of the cracker; – moisture content and feed rate; – shaft speed and feed rate. There exist interaction between cracked, uncracked shell, damaged, undamaged kernel, and palm kernel nut breakage ratio. While, there was no significant difference among interaction between moisture content, shaft speed and feed weight. The result also indicated that for the highest speed of 1,800 rpm at a feed rate of 700 kg/h for all moisture contents, the cracking efficiency was between10 to 90 %, which implies that the kernel cracking efficiency increases with an increase in machine speed. However, it was observed that higher cracking efficiency was at the cost of higher kernel damage for all cracking speeds and feed rates, which is a problem. The kernel breakage ratio ranged from 1.040–7.85 for all feed rates and moisture contents. The kernel breakage ratio increased with moisture content and cracking speed but decreases with feed rate weight.

The effect of resin coating on the quality characteristics of chicken eggs during storage.

In this study, after washing, changes in the quality characteristics of chicken eggs coated with apricot, almond, and sour cherry tree resins were examined during two different temperatures (4 °C and 22 °C) storage for 60 days. While air cell height, weight loss, albumen and yolk pH and a* (redness) values increased in all samples during storage, Haugh unit, albumen and yolk index, shell fracture and vitelline membrane strength, albumen and yolk L* (lightness) and b* (yellowness) values decreased (P<0.05). The lowest weight loss (0.54g) and air cell height (2.89mm), highest Haugh unit (73.95 HU), albumen index (8.81%), and yolk index (40.37%) were found in the samples coated with sour cherry wood resin stored at 4 °C. The shell breakage and vitelline membrane strength of the coated samples were determined to be higher than the control samples and the samples stored after washing. Higher weight loss, air cell height, and pH values, while lower Haugh unit, Albumen and yolk index were found in samples stored at 22 °C (P<0.05). At the end of storage, the maximum increase in the counts of total aerobic mesophilic and psychrophilic bacteria was found in the albumin and egg yolk of washed samples stored at ambient temperature. As a result, the coating materials prepared with the resin of apricot, almond, and sour cherry trees were suitable for eggshell's shelf life extension. PRACTICAL APPLICATION: The consumers demand the eggs be in their freshest condition, but the currently available storage conditions are not sufficient to maintain freshness in many regions of Turkey. The physical, chemical and, microbiological qualities of the eggs coated with wood resins were determined to be superior compared to other samples. Because resins have good barrier properties, it is recommended to conduct extensive studies on their applicability in different products.

Taphonomy and palaeoecology of deep-water chemosymbiotic bivalves from the Eocene of Outer Eastern Carpathians, Ukraine

The paper reports rare occurrence of deep-water solemyid and lucinid bivalves from Cenozoic sequences of Outer Eastern Carpathians, Ukraine. The studied bivalves occur in the Eocene Pasichna Formation, represented by deep-water marls and pelagic limestones intercalated with thin-bedded calcareous sandstones yielding material re-deposited from shallow water. This find offered a chance to study the unaltered shell breakage pattern of these deep-burrowing solemyid bivalves buried in situ by turbidites. The breakage includes arcuate breaks representing likely syn-vivo damage related to active burrowing of the animal while telescopic breaks are most likely post-mortem distortions produced by the load of the heavy sediment covering sea bottom after a turbiditic event. Taxonomic study indicates that both solemyid and lucinid bivalves from the Eocene of the Pasichna Formation are most similar to deep-water members of their respective clades, known from roughly coeval deposits from the Tethys. The available evidence indicates that bivalves in question lived on the deep-sea muddy bottom, influenced by turbidite deposits, and were buried by them syn-vivo or early post-mortem. This is in contrast to the great majority of molluskan faunas from the Carpathian Paleogene, reworked during transport downbasin from shallow-marine settings by mass gravity flows. The detailed study of the occurrence mode of deep-water bivalves in the Carpathian part of the Tethys during the Paleogene, influenced by frequent build-up of oxygen-depleted waters, offers implications for the evolutionary histories of both groups in question. For both solemyids and lucinids, adaptations to oxygen-depleted environments are primordial, and are carried from the Silurian until today, as supported by the presented fossil and actualistic evidence. This is in contrast to their histories in high-redox potential environments, with solemyids known from cold seeps from the Devonian onwards and lucinid seep record only from the Jurassic onwards.

Oxidation and ignition of a heterogeneous Al-Zn alloy powder metallic fuel

In this work, a heterogeneous Al-Zn alloy was developed as a metallic fuel to overcome the ignition time delay and low combustion rate of Al energetic materials. Al-Zn alloy powders were prepared by a high-speed centrifugal atomization method, which distributed Al and Zn uniformly on the surfaces and insides of the resulting spherical particles. The temperature at which the particles’ oxide shells cracked was lower and the laser ignition delay was 35 ms shorter for the Al-Zn alloy than for Al, based on TG-DSC results. The reason is that the low-temperature vaporization of Zn exacerbated the breakage of Al2O3 shells, and the heat accumulated during the vapour-phase combustion of Zn heated the particle to the reaction temperature of Al. Therefore, the addition of Zn enhances the combustion behaviour of Al by accelerating the rate of heat release.

DUROPHAGOUS FISH PREDATION TRACES VERSUS TUMBLING-INDUCED SHELL DAMAGE—A PALEOBIOLOGICAL PERSPECTIVE

ABSTRACTDurophagous (shell-crushing) fish predation is considered to have been a major force of evolutionary change in the history of marine communities. However, because fish predators are very rarely preserved in the act of predation, fossil evidence of such interactions is commonly indirect. For instance, it has been argued that shell fragments with sharp margins constitute a good proxy for durophagy. However, drawing a distinction between predation- and abiotic-induced shell damage can be challenging. Notably, experimental data on shell fragmentation by marine durophagous fishes are almost lacking. In this study, we explore whether shell breakage caused by durophagous marine fishes versus physical factors can be distinguished. Aquarium experiments involving commercially available predatory fishes (Diodon) and thin-shelled invertebrate preys (gastropods Nassarius and brachiopods Frenulina) show that the predation by some fish produces shell fragments displaying extremely low roundness and varying degree of sphericity. Importantly, these fragments typically display sharp and jagged margins, and reveal distortion of individual crystal fibers. Tumbling experiments showed that the disintegration of brachiopod shells proceeds much more rapidly than that of gastropods, which may suggest that abiotic-induced fragmentation of brachiopods may be eventually confused with predation. However, the tumbling-induced fragmentation and damage in both groups are typically characterized by the presence of spherical or discoidal and rounded shell fragments displaying smooth edges (without any microstructural distortion), and numerous abrasive scratches and wear scars on the surface. These data underscore that the shell fragments produced by a durophagous fish, if not subsequently abraded by physical factors, can be recognized in the fossil record.

PATTERNS OF UNREPAIRED SHELL DAMAGE IN RECENT BRACHIOPODS FROM FIORDLAND (NEW ZEALAND)

In order to provide quantitative data concerning patterns of shell breakage and repair in rhynchonelliform brachiopods, we studied undisturbed death assemblages from a New Zealand fiord complex where three species of terebratulide and one rhynchonellide occur in dense mixed patches on the near vertical walls. Proportions of damaged (both repaired and non-repaired) individuals varied between both taxa and sampling site. However, the general observation was that few individuals show signs of having been able to repair damage but the proportion of individuals showing unrepaired, and hence presumably fatal, breakages was higher (up to 76% in Magasella sanguinea from one sample from Tricky Cove in Doubtful Sound). Damage was mostly concentrated around the anterior margins and affected both valves and is consistent with having been clamped between a set of either jaws or claws. Potential culprits include fish (wrasse), rock lobsters and echinoids. As yet it is unclear whether the damage results from deliberate feeding activity or as collateral damage from grazers feeding on other organisms on the fiord walls which may allow secondary predation by asteroids. The net effect is, however, the same, in that the damage appears to have been fatal. More structured sampling is now required to understand the spatial variation in this damage and mortality, and also to establish the culprits with more certainty.

Roughening of hollow glass microspheres by NaF for Ni electroless plating

Roughening of non-conductive substrate ceramic materials with hydrofluoric acid (HF) is usually an essential step to enhance adhesion of the coating by electroless chemical plating. However, the violent reaction between HF and the hollow glass microspheres (HGMs) usually causes breakage and damage of the thin shells of HGMs. This paper proposes a modified roughening strategy for Ni electroless plating, i.e., eroding HGMS slowly with a mixture of sodium fluoride (NaF) and hydrochloric acid (HCl). The Na2SiF6 by-products from the reaction of NaF with SiO2 were erased by the following NaOH washing to expose the surface of HGMs without any obvious pores or breakage. Such a modified roughening and followed alkali washing strategy can thus not only reduce the surface corrosion, but also hinder the further damage of HGMs by covering Na2SiF6 sediments. The successive plating of uniform Ni nanoparticles on HGMs was conducted, and the related mechanism was discussed in detail.

Almond physical traits affected by rootstocks in ‘Marinada’ cultivar

Several rootstocks are available for almond, including different hybrids from several Prunus species. Results from a comparative trial planted in Borges Blanques, Lleida (northeastern Spain) grafting ‘Marinada’ onto 10 different rootstocks are presented. Rootstocks are ‘INRA®-GF-677’, ‘Garnem®’, ‘Cadaman’, ‘Ishtara®’, ‘IRTA-1’, ‘IRTA-2’, ‘Puebla del Soto’, ‘ROOTPAC®-70-R’, ‘ROOTPAC®-40’, and ‘ROOTPAC®-20’. Physical traits of the kernel (before and after blanching) and mechanical properties of both kernel and shell were studied. Statistical analysis showed significant differences between rootstocks for almost all the variables. The less vigorous rootstocks (‘ROOTPACK®-20’, ‘Ishtara®’ and ‘ROOTPAC®-40’) produced kernels of lower quality (small weight and size, darker blanched kernel) and with higher risk of kernel breakage, but also produce a stronger shell. The more vigorous rootstock (‘Garnem®’, ’INRA®-GF-677’ and ‘Cadaman’) showed the opposite effects. Shell strength is significantly higher in those rootstocks with lower production (‘ROOTPAC®-40’, ‘IRTA-2’ and ‘Puebla del Soto’), while shell flexibility was higher in rootstocks with higher crop load (‘INRA®-GF-677’, ‘Garnem®’ and ‘Cadaman’) that also result in higher risk of external shell breakage (double-shell characteristic).

Ocean acidification and molluscan shell taphonomy: Can elevated seawater pCO2 influence taphonomy in a naticid predator–prey system?

The size and frequency of gastropod drill holes in shells of their prey are common indicators of predator-prey ecology in the fossil record. Taphonomic processes occurring after predation, however, can influence the preservation of shells in a given fossil assemblage and can thus influence ecological inferences based on preserved shells. To determine if ocean acidification (OA) has the capacity to influence prey shell taphonomy in a gastropod drilling predation system, we tested for effects of elevated pCO2 on dissolution rates, breakage force, and drill hole diameters in non-fragmented shells of two prey species of the cannibalistic naticid gastropod, Euspira heros. Drilled and non-drilled shells of Littorina littorea and E. heros were exposed to control (~300 μatm) and elevated (~800 and 4000 μatm) pCO2 treatments for five weeks. Dry shell weight and drill hole diameter (outer and inner) were recorded for individual shells before and after exposure; the force required for shell breakage was recorded at the end of the exposure period. Shell mass loss in 800 and 4000 μatm, respectively, were ~1 and 7% for E. heros, and ~0 and 4% for L. littorea, compared to ~0% in the control for both species. Shell breakage force was unaffected by elevated pCO2, but was affected by species and drill hole presence, with E. heros shells requiring a force of ~220 and 269 Newtons in drilled and non-drilled shells, respectively, compared to ~294 and 415 Newtons in L. littorea. At 4000 μatm, outer drill hole diameter significantly increased by ~12% for E. heros, while inner drill hole diameter significantly increased by ~13% in E. heros and ~10% in L. littorea. Ultimately, this study provides the first documentation of molluscan shell taphonomy in the context of OA for a gastropod drilling predation system and sets the stage for future research.

WHAT CAN WE LEARN FROM ALL THOSE PIECES? OBTAINING DATA ON DRILLING PREDATION FROM FRAGMENTED HIGH-SPIRED GASTROPOD SHELLS

Studies on drilling predation in the fossil record often analyze site stereotypy and drilling frequency. Postmortem prey shell breakage can create particular problems for these analyses, especially in high-spired gastropods (e.g., normalizing drill hole location and estimating the number of individuals in a sample). As a result, many previous studies of these taxa have considered only “complete specimens” though “completeness” is rarely well defined, thereby frequently excluding much potential data. We applied two approaches to collect predation data from incomplete shells of Turritella alumensis from the Pliocene Jackson Bluff Formation in Florida. First, we studied site stereotypy using a Theoretical Apex System to normalize drill hole location. Including incomplete specimens revealed a different pattern of site stereotypy than some previous authors have noted: we found two potential populations of drillers acting on different portions of the shells. Second, we calculated drilling frequency by creating a new calculation for normalizing the minimum number of individuals of high-spired gastropods within a sample, making it possible to compare samples with variable amounts of shell breakage. The calculated drilling frequency for shells drilled by larger predators generated using this method was consistent with that calculated using only “complete” specimens. Additional studies are needed to determine whether drilling frequencies calculated using “complete” specimens are always consistent with those generated using the minimum number of individuals method introduced here.

Model comparison to evaluate a shell quality bio-complex in layer hens

Reducing the incidence of egg shell breakage is an important selection goal in egg layer hens breeding. Breaking strength provides an indicator of static shell resistance correlated with shell thickness. Acoustic egg tests combine shell's resonance profile with egg mass to calculate dynamic stiffness (KDyn) a quantitative indicator of integral shell resistance, and a novel direct detection of both cracks and micro-cracks (MCr) making it possible for use in selection programs aiming improvement of shell quality. A shell quality bio-complex was defined to improve overall shell quality, including: breaking strength at equator (BSe) and poles (BSp), KDyn, and MCr, on multiple eggs/hen-age. A total of 81,667; 101,113; and 72,462 records from 4 generations of three pure lines were evaluated. Two models were tested in the brown-egg line: I) four-trait linear repeatability model and II) three-trait linear (BS, KDyn)-threshold (MCr) in the three lines. Models were implemented with AIREMLF90 and THRGIBBS1F90. Heritability and repeatability (Model I) estimates were: h2 = 0.14, 0.18, 0.33, and 0.02; r = 0.16, 0.28, 0.43, and 0.03 for BSe, BSp, KDyn, and MCr, respectively. Corresponding values in White Plymouth Rock were h2 = 0.14, 0.17, 0.33, and 0.02; r = 0.21, 0.33, 0.44, and 0.04, and in White Leghorn were h2 = 0.14, 0.23, 0.36, and 0.02; r = 0.24, 0.38, 0.52, and 0.02. Genetic correlations between BSe and BSp were between 0.51 and 0.68. The BS traits were moderately correlated with KDyn (+0.23 to +0.51), and tended to be negatively correlated with MCr. KDyn, and MCr (-0.46 to -0.62). Model II had similar results; except for increased h2 = 0.06 and r = 0.09 for MCr. Results indicate that BSe and BSp are different traits; while incidence of MCr is low in heritable but showed negative genetic correlations with the other traits. This makes MCr unsuitable for direct selection; but favors indirect selection against MCr via BSe, BSp, and KDyn for a holistic selection to improve shell quality, in particular to achieve the ultimate goal, reduction of egg breakage.