Reduced Feeding Rates Research Articles

Developing behavioural ecotoxicology assessment methods in the tropical marine amphipod, Parhyale hawaiensis: A study with benzo[a]pyrene (BaP)

Toxicant-induced behavioural changes provide important insights into environmental toxicity, particularly in vulnerable tropical marine habitats. However, ecotoxicological knowledge of organisms in these environments is insufficient. We aimed to develop innovative and cost-effective ecotoxicology methods using Parhyale hawaiensis as a tropical model organism. Adult P. hawaiensis were exposed to aqueous benzo[a]pyrene (BaP) (2 μM) and dietary BaP (50, 250, or 1250 μg BaP/g diet). Survival (24 to 96 h) and behavioural responses (21d) to foraging, reproduction, and predator avoidance were studied. Aqueous and dietary exposures to benzo[a]pyrene (BaP) did not affect survival but induced significant immobility with effective concentration (EC50 ± SE, 96 h at 11.89 ± 1.19 μM). Relative to the control group, aqueous exposure to 2 μM and dietary exposure to 250 and 1250 μg BaP/g feed resulted in statistically significant behavioural changes. These included a 55–76 % reduction in feeding rates, 133 % increase in chemosensation time, 60–122 % drop in moulting frequency, 200 % delay in precopulatory activity, 50–83 % decrease in geotactic activity, and 300–400 % increase in phototactic activity (all significant at p ≤ 0.05). The methods developed in this study are cost-effective, sensitive, and readily integrated into other endpoint analyses, reinforcing the potential of P. hawaiensis as a tropical ecotoxicology model for detecting toxicant-induced behavioural responses and enhancing marine risk assessments.

The effect of external flow on 3D orientation of a microscopic sessile suspension feeder, Vorticella convallaria.

Vorticella convallaria are microscopic sessile suspension feeders that live attached to substrates in aquatic environments. They feed using a self-generated current and help maintain the health of aquatic ecosystems and wastewater treatment facilities by consuming bacteria and detritus. Their environmental impact is mediated by their feeding rate. In ambient flow, feeding rates are highly dependent on an individual's orientation relative to the substrate and the flow. Here, we investigate how this orientation is impacted by flow speed. Furthermore, we examined whether individuals actively avoid orientations unfavorable for feeding. We exposed individuals to unidirectional laminar flow at shear rates of 0, 0.5, 1.0, and 1.5 s-1, and recorded their 3D orientation using a custom biplanar microscope. We determined that V. convallaria orientation became progressively tilted downstream as the shear rate increased, but individuals were still able to actively reorient. Additionally, at higher shear rates, individuals spent a larger fraction of their time in orientations with reduced feeding rates. Our shear rates correspond to freestream flows on the scale of mm s-1 to cm s-1 in natural environments.

Investigation of optimal machining Monel 400 superalloy considering carbon emissions using FEM, regression and ANN methods

In this study, the optimal machining parameters for the machining of Monel 400 superalloy considering carbon emission were investigated. Monel 400 stands out among nickel alloys with its resistance to high corrosive environments. First, the Johnson-Cook material model for Monel 400 was developed for FEM simulations. Then, FEM simulations were performed using seven different machining parameters, including cutting and geometric, and validated with experimental results in the literature. The obtained FEM results were trained and predicted by regression and Artificial Neural Network (ANN) analysis. With this study, the Johnson-Cook material model of Monel 400 superalloy and the optimal machining parameters considering carbon emission with different cutting and geometric machining parameters are provided to the literature. As a result, it was determined that the most effective machining parameters in terms of cutting force were 139.04% increase in depth of cut, 74.23% increase in feed and 9.57% decrease in side rake angle. In terms of carbon emission, the most effective machining parameters were found to be −338.9g reduction in depth of cut, −294.3g reduction in feed rate and −171.9g reduction in cutting speed. In terms of training and prediction of FEM results, it was observed that the regression model was 89.19% for cutting force data and 95.39% for carbon emission, while the ANN model was 98.081% for cutting force data and 99.978% for carbon emission. Optimal machining parameters were determined by ANN method. The optimal machining parameters (cutting speed, feed, cutting depth, side rake angle, back rake angle, lead angle and nose radius) of Monel 400 superalloy with the lowest cutting force and carbon emission were determined as 100 m/min, 0.15mm/rev, 0.375 mm, 0°, 5°, 0°, 0°, 0°, 0.4 mm and 100 m/min, 0.2mm/rev, 0.25 mm, −5°, 5°, 0°, 0.8 mm, respectively.

Nectar cardenolides and floral volatiles mediate a specialized wasp pollination system.

Specialization in plant pollination systems can arise from traits that function as filters of flower visitors. This may involve chemical traits such as floral volatiles that selectively attract favoured visitors and non-volatile nectar constituents that selectively deter disfavoured visitors through taste or longer-term toxic effects or both. We explored the functions of floral chemical traits in the African milkweed Gomphocarpus physocarpus, which is pollinated almost exclusively by vespid wasps, despite having nectar that is highly accessible to other insects such as honeybees. We demonstrated that the nectar of wasp-pollinated G. physocarpus contains cardenolides that had greater toxic effects on Apis mellifera honeybees than on Vespula germanica wasps, and also reduced feeding rates by honeybees. Behavioural experiments using natural compositions of nectar compounds showed that these interactions are mediated by non-volatile nectar chemistry. We also identified volatile compounds with acetic acid as a main component in the floral scent of G. physocarpus that elicited electrophysiological responses in wasp antennae. Mixtures of these compounds were behaviourally effective for attraction of V. germanica wasps. The results show the importance of both volatile and non-volatile chemical traits as filters that lead to specialization in plant pollination systems.

Ductile–brittle transition and ductile-regime removal mechanisms in micro- and nanoscale machining of ZnS crystals

The ductile–brittle transition and ductile-regime removal mechanisms of ZnS crystal, a typical soft-brittle infrared optical material, have remained unclear at the micro- and nanoscale. In this context, this study modeled the energies consumed in two machining modes, namely ductile deformation and brittle fracture, during the ultraprecision cutting of ZnS crystal. Subsequently, based on the transition point of the energy mode, the critical undeformed chip thickness (CUCT) for the ductile–brittle transition of the material was determined. Additionally, the effect of tool parameters on CUCT was quantitatively analyzed, and the correctness of the model was verified by scratch experiments. Moreover, the cutting parameters that affect the maximum undeformed chip thickness (MUCT) were analyzed. By comparing the MUCT and CUCT, the cutting conditions to realize ductile-regime machining were predicted. The correctness of the ductile-regime machining conditions was also verified through surface quality characterization after face-cutting experiments. The MUCT can be controlled to be less than the CUCT by using a cutting tool with a sufficiently large tool rake angle, a nose radius and a reduced feed rate, thus realizing the ductile-regime removal of the material. The surface morphology, chip morphology, and surface roughness of machined ZnS crystal confirmed the validity of the model. Using a diamond cutting tool with a large cutting edge angle (–25°) and nose radius (1.2 mm) as well as a low feed rate (0.5 μm/rev) and depth of cut (3 μm), the generation of cracks and pits was effectively inhibited, resulting in a smooth surface with a surface roughness of 1.60 nm. Overall, the findings of this study provide important insights into the superfinishing of soft–brittle materials such as ZnS crystal.

Grazing inhibition in Daphnia and Bosmina by colony formation of Desmodesmus subspicatus triggered by sodium octyl sulfate.

There are growing concerns that several aquatic contaminants can indirectly alter biological interactions by inhibiting the adaptive phenotypic plasticity of organisms, even at nonlethal concentrations. In Scenedesmaceae, a family of green algae, many chemicals interfere with defensive colony formation against grazers (i.e., through induced or limited coloniality). Although several studies have demonstrated that the effects of coloniality can limit the feeding capacity of Daphnia spp., grazing inhibition in other zooplankton species is not well understood. In this study, we examined the influence of sodium octyl sulfate (SOS) on the growth and morphology of Desmodesmus subspicatus and on the feeding rates of three cladoceran species (Daphnia galeata, Bosmina longirostris, and Bosmina fatalis) feeding on SOS-induced colonies under factorial conditions of different food levels and grazer ages. SOS remarkably induced colony formation with no observed effect on growth in D. subspicatus. D. galeata and B. fatalis showed a remarkable reduction in feeding rates when they fed on colonial D. subspicatus, whereas no significant effect of the prey morphotype was found on the feeding rates of B. longirostris. Microscopic observations of algal morphology after being grazed showed that each species can consume colonial prey depending on food level and age. Comparisons of the inhibition ratio of feeding among the three cladocerans revealed that Daphnia was more sensitive to prey coloniality compared with Bosmina. Our findings provide specific insights into the effects of chemically interfered colony formation on population dynamics and community structures.

Experimental study of rotary ultrasonic high-quality hole processing of Glass Fiber Reinforced Plastic with a new diamond trepanning bit

Glass Fiber Reinforced Plastic is widely used in manufacturing and other fields because of its high specific strength and high specific modulus. Since the workpiece requires secondary hole processing during assembly, machining defects are prone to occur during hole making, which seriously affects the service life of the workpiece. A novel type of thin-walled diamond trepanning bit was fabricated and combined with ultrasonic processing technology to conduct a pilot study on hole processing. Compared with conventional twist drill hole processing, the novel diamond trepanning bit grinding hole-making method can significantly reduce the axial force when drilling, and effectively reduce the delamination and tearing damage at the exit of the hole, so that the delamination ratio at the exit is reduced by 9.6%. Combined with ultrasonic machining technology, hole machining experiments were carried out, and the results showed that: spindle speed increase or feed rate reduction can make axial force, hole wall surface roughness, and exit delamination damage all show a decreasing trend. Compared with conventional machining, the rotary ultrasonic hole machining technology can effectively reduce the axial force by 20.1% and effectively reduce the exit delamination problem by 7.3% in the delamination ratio. At the same time, considering the hole-making quality and efficiency, rotary ultrasonic processing can better reflect the advantages of the process and obtain better hole-making quality at the speed of 3000–4000 r/min and the feed rate of 14–20 mm/min. The above research can provide theoretical and technical support for the hole processing problems of Fiber Reinforced Plastic, which has important engineering application value.

Addressing amino acid-derived inhibitory metabolites and enhancing CHO cell culture performance through DOE-guided media modifications.

Previously, we identified six inhibitory metabolites (IMs) accumulating in Chinese hamster ovary (CHO) cultures using AMBIC 1.0 community reference medium that negatively impacted culture performance. The goal of the current study was to modify the medium to control IM accumulation through design of experiments (DOE). Initial over-supplementation of precursor amino acids (AAs) by 100% to 200% in the culture medium revealed positive correlations between initial AA concentrations and IM levels. A screening design identified 5 AA targets, Lys, Ile, Trp, Leu, Arg, as key contributors to IMs. Response surface design analysis was used to reduce initial AA levels between 13% and 33%, and these were then evaluated in batch and fed-batch cultures. Lowering AAs in basal and feed medium and reducing feed rate from 10% to 5% reduced inhibitory metabolites HICA and NAP by up to 50%, MSA by 30%, and CMP by 15%. These reductions were accompanied by a 13% to 40% improvement in peak viable cell densities and 7% to 50% enhancement in IgG production in batch and fed-batch processes, respectively. This study demonstrates the value of tuning specific AA levels in reference basal and feed media using statistical design methodologies to lower problematic IMs.

Lethal and sublethal implications of low temperature exposure for three intertidal predators

Benthic invertebrate predators play a key role in top-down trophic regulation in intertidal ecosystems. While the physiological and ecological consequences of predator exposure to high temperatures during summer low tides are increasingly well-studied, the effects of cold exposure during winter low tides remain poorly understood. To address this knowledge gap, we measured the supercooling points, survival, and feeding rates of three intertidal predator species in British Columbia, Canada — the sea stars Pisaster ochraceus and Evasterias troschelii and the dogwhelk Nucella lamellosa — in response to exposure to sub-zero air temperatures. Overall, we found that all three predators exhibited evidence of internal freezing at relatively mild sub-zero temperatures, with sea stars exhibiting an average supercooling point of −2.50 °C, and the dogwhelk averaging approximately −3.99 °C. None of the tested species are strongly freeze tolerant, as evidenced by moderate-to-low survival rates after exposure to −8 °C air. All three predators exhibited significantly reduced feeding rates over a two-week period following a single 3-h sublethal (−0.5 °C) exposure event. We also quantified variation in predator body temperature among thermal microhabitats during winter low tides. Predators that were found at the base of large boulders, on the sediment, and within crevices had higher body temperatures during winter low tides, as compared to those situated in other microhabitats. However, we did not find evidence of behavioural thermoregulation via selective microhabitat use during cold weather. Since these intertidal predators are less freeze tolerant than their preferred prey, winter low temperature exposures can have important implications for organism survival and predator-prey dynamics across thermal gradients at both local (habitat-driven) and geographic (climate-driven) scales.

Impact of native and invasive cyclopoid predators in relation to the diversity of the zooplankton community

Abstract The ecological impact of invasive species may be less in communities with high species diversity. We hypothesized that the feeding rates of an invasive copepod would be unaffected by high species diversity of prey in the medium as compared with a native species which would have reduced feeding rates under similar conditions. The biotic resistance to prey consumption was evaluated by testing consumption rate of the invasive species: Mesocyclops pehpeiensis and the native species: Mesocyclops longisetus curvatus, Acanthocyclops americanus, Eucyclops sp. and Microcyclops dubitabilis separately exposed to two treatments: high diversity with 13 prey species (rotifers and microcrustaceans) and low diversity with three prey species (determined on the basis of previous studies on zooplankton diversity in Mexican water bodies). We also tested the prey preference index of M. pehpeiensis in the absence and presence of the native copepod M. longisetus curvatus. M. pehpeiensis consumed the same number of prey in both treatments, regardless of high or low diversity conditions, whereas the four native species consumed less prey in the high diversity than the low diversity treatments. High community diversity may not represent an obstacle to the successful establishment of the invasive exotic copepod M. pehpeiensis.

The Nutritional Management of a Post COVID-19 Patient With Recurring High Gastric Residual Volumes: A Case Study

ObjectivesThis case study illustrates the nutritional assessment and management of a post Coronavirus disease-19 (COVID-19) patient with a recurring high gastric residual volume (GRV). Patients with COVID-19 can present with gastrointestinal (GI) symptoms that include a high GRV. The enteral nutrition (EN) guidelines regarding the management of high GRVs vary. The 2016 American Society of Parenteral and Enteral Nutrition (A.S.P.E.N) guidelines were followed. MethodsMr. X, a 67-year-old patient with multiple comorbidities, was admitted to our facility in mid December 2020 and discharged in mid July 2021. Two months after recovering from his COVID-19 infection, Mr. X presented with recurrent high GRVs. EN interventions included reduced feeding rates, use of elemental versus standard formulas, and fiber free versus fiber containing formulas. Other nutritional interventions included the use of parenteral nutrition for supplemental or total nutrition needs. The medical interventions included the management of blood glucose, electrolytes, and medications. The high GRVs continued during his prolonged hospital stay and on discharge despite different nutritional and medical interventions. ResultsDespite following the 2016 A.S.P.E.N guidelines in managing Mr. X’s high GRV there were no clear reductions in the high GRVs. Our observations about GI disturbances in post-COVID-19 patients are supported by other studies. Even after addressing known factors that can contribute to a high GRV such as electrolyte imbalances and the use of hyperosmolar formulas, Mr. X continued to show high GRVs. ConclusionsThe key learning point in this case study is that the patient did not experience the complications that would be anticipated due to GRVs at this magnitude. Neither did he respond as expected to recommended nutritional strategies. It is plausible that a high GRV is associated with post-COVID-19. The observation of an increased number of patients with post-COVID-19 GI complications has nutritional implications for clinical practice. Our study adds to the existing literature about the nutritional management of post-COVID-19 patients. Funding SourcesThere were no funding sources.

Effects of prey density and flow speed on plankton feeding by garden eels: a flume study.

ABSTRACTFeeding by zooplanktivorous fish depends on their foraging movements and the flux of prey to which they are exposed. While prey flux is a linear function of zooplankton density and flow speed, those two factors are expected to contribute differently to fish movements. Our objective was to determine the effects of these factors for garden eels, stationary fish that feed while anchored to the sandy bottom by keeping the posterior parts of their bodies inside a burrow. Using a custom-made flume with a sandy bottom, we quantified the effects of prey density and flow speed on feeding rates by spotted garden eels (Heteroconger hassi). Feeding rates increased linearly with prey density. However, feeding rates did not show a linear relationship with flow speed and decreased at 0.25 m s−1. Using label-free tracking of body points and 3D movement analysis, we found that the reduction in feeding rates was related to modulation of the eel's movements, whereby the expected increase in energy expenditure was avoided by reducing exposure and drag. No effects of flow speed on strike speed, reactive distance or vectorial dynamic body acceleration (VeDBA) were found. A foraging model based on the body length extended from the burrow showed correspondence with observations. These findings suggest that as a result of their unique foraging mode, garden eels can occupy self-made burrows in exposed shelter-free sandy bottoms where they can effectively feed on drifting zooplankton.

PLAG alleviates cisplatin-induced cachexia in lung cancer implanted mice

Chemotherapy-induced cachexia has been a significant challenge to the successful treatment of cancer patients. Chemotherapy leads to loss of muscle, loss of appetite, and excessive weight loss, which makes these necessary treatments intolerable for most patients. Therefore, it is necessary to alleviate cachexia to successfully treat cancer patients.In this study, tumor-implanted mouse models administered cisplatin showed rapid weight loss and reduced feeding rate by the second week of treatment, and 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG) effectively alleviated cisplatin-induced cachexia. In mice treated with cisplatin on a sacrificial day after 6 weeks, the weight of the two major leg muscles (quadriceps femoris and gastrocnemius) were reduced by up to 70%, but this muscle reduction was successfully prevented in the PLAG co-treatment group. The distribution and size of muscle fibers that appear in small units in cisplatin-treated mice were restored to normal levels by PLAG co-treatment. Furthermore, myostatin expression levels were upregulated by cisplatin, whereas myostatin decreased to normal levels with muscle recovery in the PLAG co-treated group. Tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), which are commonly expressed in cachexia, were significantly increased in cisplatin-treated mice but were reduced to normal levels in PLAG co-treated mice. Glucose absorption, an indicator of muscle tissue activity, decreased with cisplatin treatment and recovered to normal levels with PLAG co-treatment. Overall, PLAG effectively alleviated cisplatin-induced cachexia symptoms and reduced tumor growth in tumor-implanted mice.These findings suggest PLAG may be a promising drug to alleviate cachexia in cancer patients receiving chemotherapy.

Effects of Acclimation to Diluted Seawater on Metabolic and Growth Parameters of Underyearling Masu Salmon (Oncorhynchus masou).

We examined the effects of environmental salinity and feeding status on the growth and metabolic parameters of underyearling masu salmon. Fish were first acclimated to salinities of 0 (< 0.1), 11, or 22 psu for 10 days, after which time 50% of the fish in each group were fasted for 5 days followed by refeeding for 5 days. No effects on body length/weight were observed over the 20 days from the beginning of the experiment. Gill Na+, K+-ATPase (NKA) activity increased 20 and 10 days after transfer to water at 11 and 22 psu, respectively. Serum Na+ and Cl- levels were high in fish at 22 psu on day 20 but much lower than those in the environmental water, suggesting that fish at this salinity were able to hypo-osmoregulate. However, acclimation to 22 psu resulted in a reduction in feeding rate on day 20. Serum insulin-like growth factor (IGF)-I levels and liver glycogen content were reduced by fasting and restored after 5 days of refeeding, except in the fish at 22 psu. Intensities of serum IGFBP-1a and -1b bands were increased at higher salinities, whereas fasting/refeeding affected only IGFBP-1b. The present study suggests that acclimating masu salmon parr to 11 psu had no effect on metabolic and growth parameters, while 22 psu presumably suppressed their growth potential due to the possible energy cost or stress for osmoregulation. The disparate responses of circulating IGFBP-1a and -1b to higher salinity and fasting highlight their utility as indices of various catabolic statuses.

Effects of restricted feeding levels and stocking densities on water quality, growth performance, body composition and mucosal innate immunity of Nile tilapia (Oreochromis niloticus) fry in a biofloc system

In aquaculture feed accounts for more than 50% of current costs. Biofloc has the potential to compensate for food reduction, so restricted feeding levels should be investigated to decrease food consumption. The present study conducted to evaluate the effect of restricted feeding levels and stocking densities on water quality, growth performance, body composition and mucosal innate immunity of Nile tilapia (Oreochromis niloticus) fry in biofloc system (BFT). A 5*2 factorial experimental design was used with five restricted feeding levels (0, 15, 30, 45 and 100) and 2 stocking densities(500 fish/m3 and 1000fish/m3) comprising 10 treatments for BFT and for each density there were clear water (CW) system as control with three replicates. Fry with initial weight of 3.2 ± 0.05 g were stocked in tank(40 L), fed three times a day at 8:00, 12:00 and 16:00. Molasses was added to BFT treatments as organic carbon source at a C/N ratio of 15. Results showed that, growth indices (WG, DGR, SGR, FCR), water quality parameters (TAN, NO2, NO3, settled solids and total suspended solids), as well as innate immunity (Total immunoglobulin, Lysozyme and Catalase activity) were improved in biofloc system compared to the CW system. The reduction of feeding rate resulted in significantly decreasing growth performances and immunity among biofloc groups (p < 0.05) except for the group with 15% feed reduction in stocking density of 500/m3. Stocking density had significantly (p < 0.05) reverse effect on growth indices except for the biofloc treatment 1000/m3 without feed reduction. Proximate analysis revealed that by reduction of feeding rate, protein, ash and moisture contents increased, whereas lipid contents decreased significantly (p < 0.05). Survival rate was high (94.8–100%), and no significant differences were seen among treatments (p > 0.05) except for the non-feeding biofloc treatment with stocking density of 1000/m3 (67/9%). Innate immunity was significantly decreased by reduction of feeding rates while, Liver enzyme activity showed an increasing trend by reduction in feeding rate and increasing the stocking density (p > 0.05). These results indicate that the BFT improved water quality, growth performance and immune function of Nile tilapia fry compared to CW system. Also it is possible to decrease 15% daily feeding rate in BFT system. In conclusion, the study suggests the stocking density of 1000/m3 for larviculture of tilapia in BFT to use water and equipment more efficiently.

Assessment of emission-source contribution to spatial dispersion for coal crusher agglomeration using prognostic model

The emission of inhalable particulates (PM 10 ) from coal comminution processing is detrimental to the air quality. However, limited works have been carried out for the estimation of emission and dispersion of PM 10 from coal crushers and its ancillary operations. In this study, field-based measurements and regulatory dispersion model coupled with Weather Research Forecasting (WRF) were applied to investigate the assimilative capacity (AC) of a region with operational coal crushers. The model run was found ‘acceptable’ when compared with measured values according to set performance criteria. Furthermore, the validated model parameterization was used to forecast the dispersion effects by various emission control alternatives recommended by regulators viz. covering of conveyor belts, paving of the unpaved road, reducing feed rate, etc. Results suggested that the major contribution of PM 10 was from transportation and loading of coal after crushing, while PM 10 levels from crushing dissipated in a smaller area. Paving of transport roads and bunker/silo-based loading were effective control measures as emissions reduced by 30.67%–52.51%. The relationship between distance and emission load revealed that PM 10 concentrations below 100 μg/m 3 were achieved at approximately 750 m away from emission sources in the present study. Crusher's operations with existing emissions of 23.43 g/day/m 2 were detrimental for the region's AC and needed to be stepped down to 11.71 g/day/m 2 . In particular, using modeled meteorological data provided reasonable forecasts for allowable emissions and planning to site crusher operations. Correction to the low-wind conditions resulted in a better simulation of mean annual estimates than daily estimates of PM 10 . Such visualization of spatially explicit frameworks will guide policymakers in strengthening regulations. • Emissions from coal crushers and linked transport roads evaluated for spatial dispersion. • Transport bottlenecks are formed at feed point of crushers resulting in lower dispersion. • Emission reduction vis-à-vis dispersion by adopting controls recommended by regulators forecasted. • Paved roads and bunker/silo based loading enhanced available assimilative capacity. • Wind speed was key variable with low wind correction resulted in better mean annual estimates.

Dairy goats adjust their meal patterns to the fibre content of the diet

Few studies have investigated how meal patterns of ruminants are affected by diet fibre content. Dairy goats (N = 32) in late lactation and early gestation were housed in eight groups of four goats, with all combinations of breed (Alpine and Saanen) and lactation number (1 and 2) represented in each group. Each goat had access to its own individual feed trough placed on a weigh scale with data logged automatically. All goats were fed the same total mixed ration (TMR; 30% concentrate and 44.6% NDF in DM) ad libitum for a control period of 22 days. Using the same feed ingredients, half of the groups were then offered a High fibre diet (20% concentrate; 47.3% NDF), and the other half a Low fibre diet (40% concentrate; 41.5% NDF) for a treatment period of 16 days. Daily meal patterns (meal frequency, duration and size, feeding rate, daily feed intake and daily feeding time) were computed for each animal using a meal criterion of 8 min. The last 10 days for each period (control and treatment) were used to calculate individual period means and individual differences between the two periods. During the control period, the goats ate on average 12.1 ± 0.49 meals/day, consuming 4.2 ± 0.10 kg fresh TMR daily. When the ration changed, all measures of feeding behaviour except meal size changed asymmetrically for the goats on the two diets. Goats fed the High fibre diet reduced their meal frequency by 10%, and the first meal after feed distribution lasted 11% longer, leading to a 9% reduction in feeding rate and no significant changes in daily feed intake and daily feeding time. Goats on the Low fibre diet did not significantly change their meal frequency or meal size, but the combined changes nevertheless led to a 9% increase in daily feed intake. On the Low fibre diet, goats were able to increase their feeding rate by a third, leading to a reduction in meal durations, thus reducing daily feeding time by 13%. Goats adapt their feeding behaviour to the fibre proportion of the offered diet, with more changes when fibre content is lowered, which needs to be taken into account when comparing phenotypes and adaptability of small ruminants to different diets.

Anthropogenic noise alters parental behavior and nestling developmental patterns, but not fledging condition

Abstract Anthropogenic noise is a ubiquitous feature of the American landscape, and is a known stressor for many bird species, leading to negative effects in behavior, physiology, reproduction, and ultimately fitness. While a number of studies have examined how anthropogenic noise affects avian fitness, there are few that simultaneously examine how anthropogenic noise impacts the relationship between parental care behavior and nestling fitness. We conducted Brownian noise playbacks for 6 h a day during the nesting cycle on Eastern Bluebird (Sialia sialis) nest boxes to investigate if experimentally elevated noise affected parental care behavior, nestling body conditions, and nestling stress indices. We documented nest attendance by adult females using radio frequency identification (RFID), and we assessed nestling stress by measuring baseline corticosterone levels and telomere lengths. Based on the RFID data collected during individual brood cycles, adult bluebirds exposed to noise had significantly higher feeding rates earlier in the brood cycle than adults in the control group, but reduced feeding rates later in the cycle. Nestlings exposed to noise had higher body conditions than the control nestlings at 11 days of age, but conditions equalized between treatments by day 14. We found no differences in nestling baseline corticosterone levels or nestling telomere lengths between the two treatment groups. Our results revealed that noise altered adult behavior, which corresponded with altered nestling body condition. However, the absence of indicators of longer-term effects of noise on offspring suggests adult behavior may have been a short-term response.

Effect of Spindle Speed and Feed Per Tooth in Feed Rate Perspective on Inconel HX Cutting Force

Reducing feed rate during end-milling of nickel-based superalloys for low-cutting force has always been a common approach. This is due to these alloys having superior properties, making them widely regarded as difficult-to-machine materials. As feed rate is tied to spindle speed and feed per tooth, it is crucial to comprehend whether spindle speed, feed per tooth or the interaction between spindle speed and feed per tooth has a significant factor on cutting force reduction when increasing the feed rate. Accordingly, this manuscript presents an effect of spindle speed and feed per tooth in feed rate perspective on Inconel HX cutting force. Half-immersion down-milling and full-immersion down-milling was conducted experimentally using solid ceramic end-mill cutter. The results indicate that cutting force decreases and then increases after further increase in spindle speed, while cutting force increases with an increase in feed per tooth. Optimum spindle speed and optimum feed per tooth for low-cutting force were 21,400 rpm and 0.013 mm/tooth. Furthermore, feed per tooth was the significant factor which influenced the cutting force, whereas spindle speed, and the interaction between spindle speed and feed per tooth were not significant.

Decreased 14-3-3 expression correlates with age-related regional reductions in CNS dopamine and motor function in the pond snail, Lymnaea.

Ageing is associated in many organisms with a reduction in motor movements. We have previously shown that the rate of feeding movements of the pond snail, Lymnaea, decreased with age but the underlying cause is not fully understood. Here, we show that dopamine in the cerebro-buccal complex is an important signalling molecule regulating feeding frequency in Lymnaea and that ageing is associated with a decrease in CNS dopamine. A proteomic screen of young and old CNSs highlighted a group of proteins that regulate stress responses. One of the proteins identified was 14-3-3, which can enhance the synthesis of dopamine. We show that the Lymnaea 14-3-3 family exists as three distinct isoforms. The expression of the 29kDa isoform (14-3-3Lym3) in the cerebro-buccal complex decreased with age and correlated with feeding rate. Using a 14-3-3 antagonist (R18) we were able to reduce the synthesis of L-DOPA and dopamine in ex vivo cerebro-buccal complexes. Together these data suggest that an age-related reduction in 14-3-3 can decrease CNS dopamine leading to a consequential reduction in feeding rate.