Home About us Contact
|
Home About us Contact | ||
|
|
||
Feeding Period (feeding + period)
Selected AbstractsEffect of combined supplementation with vitamin E and alpha-lipoic acid on myocardial performance during in vivo ischaemia-reperfusionACTA PHYSIOLOGICA, Issue 4 2000Coombes Reactive oxygen species (ROS) contribute significantly to myocardial ischaemia-reperfusion (I-R) injury. Recently the combination of the antioxidants vitamin E (VE) and alpha-lipoic acid (, -LA) has been reported to improve cardiac performance and reduce myocardial lipid peroxidation during in vitro I-R. The purpose of these experiments was to investigate the effects of VE and , -LA supplementation on cardiac performance, incidence of dysrhythmias and biochemical alterations during an in vivo myocardial I-R insult. Female Sprague,Dawley rats (4-months old) were assigned to one of the two dietary treatments: (1) control diet (CON) or (2) VE and , -LA supplementation (ANTIOXID). The CON diet was prepared to meet AIN-93M standards, which contains 75 IU VE kg,1 diet. The ANTIOXID diet contained 10 000 IU VE kg,1 diet and 1.65 g , -LA kg,1 diet. After the 14-week feeding period, significant differences (P < 0.05) existed in mean myocardial VE levels between dietary groups. Animals in each experimental group were subjected to an in vivo I-R protocol which included 25 min of left anterior coronary artery occlusion followed by 10 min of reperfusion. No group differences (P > 0.05) existed in cardiac performance (e.g. peak arterial pressure or ventricular work) or the incidence of ventricular dysrhythmias during the I-R protocol. Following I-R, two markers of lipid peroxidation were lower (P < 0.05) in the ANTIOXID animals compared with CON. These data indicate that dietary supplementation of the antioxidants, VE and , -LA do not influence cardiac performance or the incidence of dysrhythmias but do decrease lipid peroxidation during in vivo I-R in young adult rats. [source] Diurnal cycle in salivary cortisol levels in common marmosetsDEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2004Nicola Cross Abstract A noninvasive method of saliva sampling was used to assess the diurnal cortisol rhythm from 0900 to 1700 hr in the common marmoset (Callithrix jacchus). The levels of cortisol were highest in the morning and declined significantly over the day. Individual marmosets varied in the magnitude of the cycle, and the greatest individual variability occurred in the morning levels. The decrease in cortisol levels was more rapid after than before the midday feeding period in subordinate marmosets (aged 53,63 months) compared to dominant marmosets (aged 79,80 months), and overall, the levels of cortisol were higher in the subordinate marmosets. We found no effect of sex on cortisol levels across the cycle. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 45: 134-139, 2004. [source] Supplemental feeding reduces natural selection in juvenile red deerECOGRAPHY, Issue 3 2002Karoline T. Schmidt In red deer, variation in winter and spring weather conditions encountered by the mothers during pregnancy and during the first year of life are a main determinant for individual life-history as well as population dynamics. We tested the hypothesis that supplementary feeding which provides constant food supply throughout winter removes the selective pressure of winter harshness on nutrition-mediated phenotypic traits. We analysed cohort variation in body weight in calves in October, before their first winter, and in yearlings in June, after their first winter, in a food-supplemented population in the Eastern Austrian Alps. Over eleven years, cohort body weight varied between years in calves and yearlings. Contrary to studies on non-supplemented red deer populations we found neither short- nor long-term effects of winter weather on body weight. In calves, autumn body weight was negatively related to April,May and June temperatures, suggesting that cool weather during the main growth period retarded plant senescence and thereby prolonged the period of high protein content of summer forage. In yearlings, variation in June body weight, shortly after the end of the feeding period, was lower after a wet April,May, suggesting a negative effect of a prolonged period of supplemental feeding. For both calves and yearlings intra-cohort variation in body weight was higher, inter-cohort variation was lower as compared to non-supplemented red deer, suggesting that in their first year of life supplemented red deer are under reduced natural selection pressure. [source] Feeding, growth and nutritional status of restocked salmon parr along the longitudinal gradient of a large European river: the AllierECOLOGY OF FRESHWATER FISH, Issue 2 2009A. Descroix Abstract,,, The feeding, growth and nutritional status of salmon parr (0+) released at fry stage in different riffles were studied in a large temperate river (Allier, France) throughout the active feeding period. Significant differences were observed along the upstream,downstream gradient. Parr growth performance and energy storage were higher in downstream riffles and low in the most upstream one. These longitudinal growth variations are discussed in the context of diet and food availability differences, habitat variables and intra- and inter-species competition. The most favourable site for optimum growth and nutritional status appeared to be the intermediary riffle located in the grayling zone. [source] Food abundance affects both morphology and behaviour of juvenile perchECOLOGY OF FRESHWATER FISH, Issue 2 2008J. Borcherding Abstract,,, Behaviour and morphology were both shown to differ between 1+ perch from two lakes that in earlier studies showed differences in size-specific predation risk. As the level of nourishment is known to affect behaviour and morphology, we fed perch of the two lakes in tanks for 40 days with two food levels, to study whether observed differences remain stable with changes in food availability. The perch fed in excess grew significantly, while the perch at the low food conditions lost weight, clearly indicating undernourishment. In aquarium experiments, the starved perch from both lakes were much bolder in the trade-off between foraging and predator avoidance than their well-fed conspecifics. In addition, the shape of perch differed significantly between feeding treatments. At low food levels perch got a more slender body, while at high food levels they developed a deeper body and a relatively smaller head. Independent of feeding level, the comparison between the two lakes revealed a clearly deeper body and a larger head area for one population, a shape difference that remained stable after the feeding period. The results give evidence that the level of nourishment is an important factor that quickly alters risk-taking behaviour. In body morphology, however, more stable shape characteristics must be distinguished from more flexible ones. Consequently, the level of nourishment is a potential factor that may quickly hide other proximate cues and must be considered attentively in studies, in which shape changes and behaviour are related to environmental factors like diet, predation pressure or habitat diversity. [source] The feeding behavior of Trichogramma brassicae: new evidence for selective ingestion of solid foodENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2000Z.X. Wu Abstract A descriptive study of the feeding behavior and structures of Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) was conducted. Based on direct observational and biochemical evidence, larvae feed predominantly on particulate materials, starting ca. 25 h post-oviposition. Feeding lasted for ca. 9 h, at 25±1 °C. During this feeding period the shape of the larvae changed from vermiform to pyriform and then to sacciform, resulting in a ca. 40-fold increase in body size. Larvae used elaborate feeding behaviors as they pulled solid food particles to their oral opening, broke small particles from larger ones, and took the particles into the stomodaeum, which is a powerful pump. In the stomodaeum, peristaltic movement further macerated the particles, which eventually passed through the cardiac valve into the midgut. As indicated by changes in fluorescently labeled casein, digestive enzymes aid in the extra-oral chemical digestion of food. The contents of the gut, during and shortly after feeding, were almost entirely closely packed solid particles. The behavioral activity of feeding larvae centered almost exclusively on processing and ingesting solid food particles. The rapid larval growth is much more plausibly explained by their feeding on the highly concentrated nutrients found in solid foods, rather than the extensive concentration required if dilute liquids were the principal source of nutrients. The implications of these findings for the development of practical artificial diets are discussed. [source] A short-term sublethal in situ toxicity assay with hediste diversicolor (polychaeta) for estuarine sediments based on postexposure feedingENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2005Susana Maria Moreira Abstract This study evaluated a short-term sublethal endpoint for in situ toxicity assays for estuarine sediments, based on postexposure feeding of the polychaete Hediste (Nereis) diversicolor Müller. A method for precisely quantifying postexposure feeding rates of H. diversicolor was established under laboratory conditions using Artemia franciscana Kellog nauplii. The sensitivity of the postexposure feeding response to copper was investigated by comparing postexposure feeding rates to growth and lethality. The 48-h and 96-h median lethal concentration (LC50) of copper were 241 and 125 ,g/L, respectively, whereas the 48-h median inhibitory concentration (IC50) for postexposure feeding and the 20-d IC50 for growth were 52 and 25 ,g/L of copper, respectively. The influence of different exposure conditions (substrate, temperature, salinity, food availability, and light) on H. diversicolor postexposure feeding was assessed; temperature and salinity were found to influence significantly postexposure feeding. The effectiveness of the proposed in situ assay was investigated by deploying it at two reference and six contaminated Portuguese estuaries. A 48-h exposure period was followed by a 1-h postexposure feeding period. High organism recoveries (89,100%) were obtained. Postexposure feeding was depressed significantly (17,90%) at all contaminated sites relatively to reference sites. The proposed in situ assay with H. diversicolor was shown to be a potential useful tool for estuarine sediment toxicity testing. [source] Impaired fear conditioning but enhanced seizure sensitivity in rats given repeated experience of withdrawal from alcoholEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2001D. N. Stephens Abstract Repeated experience of withdrawal from chronic alcohol treatment increases sensitivity to seizures. It has been argued by analogy that negative affective consequences of withdrawal also sensitize, but repeated experience of withdrawal from another sedative-hypnotic drug, diazepam, results in amelioration of withdrawal anxiety and aversiveness. We tested whether giving rats repeated experience of withdrawal from alcohol altered their ability to acquire a conditioned emotional response (CER). Male Hooded Lister rats were fed a nutritionally complete liquid diet as their only food source. Different groups received control diet, or diet containing 7% ethanol. Rats receiving ethanol diet were fed for either 24 days (Single withdrawal, SWD), or 30 days, with two periods of 3 days, starting at day 11, and 21, in which they received control diet (Repeated withdrawal, RWD). All rats were fed lab chow at the end of their liquid diet feeding period. Starting 12 days after the final withdrawal, groups of Control, SWD and RWD rats were given pentylenetetrazole (PTZ; 30 mg/kg, i.p.) three times a week, and scored for seizures. The occurrence of two successive Stage 5 seizures was taken as the criterion for full PTZ kindling. Other groups of control, SWD and RWD rats were trained to operate levers to obtain food, and were then exposed, in a fully counterbalanced design, to light and tone stimuli which predicted unavoidable footshock (CS+), or which had no consequences (CS,). Rats consumed approximately 17.5 g/kg/day of ethanol, resulting in blood alcohol levels of approximately 100 mg/dL. Repeated administration of PTZ resulted in increasing seizure scores. RWD rats achieved kindling criterion faster than either Control or SWD rats. No differences were seen in the groups in flinch threshold to footshock (0.3 mA). At a shock intensity of 0.35 mA, Control, but not RWD or SWD rats showed significant suppression to the CS+ CS, presentation did not affect response rates. The three groups differed in their response to pairing the CS+ with increasing shock levels, the Controls remaining more sensitive to the CS+. SWD rats showed significant suppression of lever pressing during CS+ presentations only at 0.45 and 0.5 mA, and RWD rats only at 0.5 mA. Giving rats repeated experience of withdrawal from chronic ethanol results in increased sensitivity to PTZ kindling, but reduces their ability to acquire a CER. Withdrawal kindling of sensitivity to anxiogenic events does not seem to occur under circumstances which give rise to kindling of seizure sensitivity. [source] Seasonal variation in habitat use by salmon, Salmo salar, trout, Salmo trutta and grayling, Thymallus thymallus, in a chalk streamFISHERIES MANAGEMENT & ECOLOGY, Issue 4 2006W. D. RILEY Abstract, A portable multi-point decoder system deployed in a tributary of the River Itchen, a southern English chalk stream, recorded the habitats used by PIT-tagged juvenile salmon, Salmo salar L., trout, Salmo trutta L. and grayling, Thymallus thymallus L., with a high degree of spatial and temporal resolution. The fishes' use of habitat was monitored at 350 locations throughout the stream during September/October 2001 (feeding period) and January/February 2002 (over-wintering period). Salmon parr tended to occupy water 25,55 cm deep with a velocity between 0.4 and 1.0 m s,1. During both autumn and winter, first year salmon (0+ group) were associated with gravel substrate during the daytime and aquatic weed at night. In autumn, 1+ salmon were strongly associated with hard mud substrates during the day and with marginal tree roots at night. In winter, they were located on gravel substrate by day and gravel and mud at night. Trout were associated with a greater range of habitats than salmon, generally occupying deeper and faster water with increasing age. During the autumn, 0+ trout were located along shallow (5,10 cm) and slow (,0.1,0.4 m s,1) margins of the stream, amongst tree roots by day and on silty substrates at night. During winter the 0+ trout occupied silty substrates at all times. As age increased, trout increasingly used coarse substrates; hard mud, gravel and chalk, and weed at night. All age groups of grayling (0+, 1+ and 2+) tended to occupy hard gravel substrate at all times and used deeper and faster water with increasing age. The 1+ and 2+ groups were generally found in water 40,70 cm deep with a velocity between 0.3 and 0.5 ms,1, whilst the 0+ groups showed a preference for shallower water with reduced velocity at night, particularly in the winter. There were greater differences in the habitats used between species and age groups than between the autumn and winter periods, and the distribution of fish was more strongly influenced by substrate type than water depth or velocity. The results are discussed in relation to the habitat requirements of mixed salmonid populations and habitat management. [source] Effects of feeding frequency on nestling begging and digestionIBIS, Issue 2 2008AMBER E. BUDDEN Nestling begging has the potential to provide parents with honest information about both short- and long-term nutritional needs, yet the importance of previous feeding experience remains largely untested in empirical studies. We examined the effect of two experimental feeding rates on nestling begging in Southern Grey Shrikes Lanius meridionalis using differences in load size to equalize the total volume of food received. There was variation in the pattern of begging behaviour between six pairs of siblings during a hand-feeding trial, although individuals maintained a similar begging intensity throughout a 9-h feeding period. Both treatment groups showed elevated begging responses during a terminal deprivation period, but nestlings fed small food items at frequent intervals demonstrated higher begging responses after a period of deprivation than did siblings fed large food items infrequently. As nestlings fed frequently with small food items had greater levels of undigested protein present in their faeces than birds fed large items infrequently, we suggest experimentally induced variation in digestive efficiency may account for the observed differences in begging behaviour. The possible role of learning, the adaptive significance of trade-offs between feeding rate and digestive efficiency, and a possible conflict of interests between parents and offspring are discussed. [source] A minipig model of high-fat/high-sucrose diet-induced diabetes and atherosclerosisINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2004Shoumin Xi Summary Type 2 diabetes is a major risk factor of the development of atherosclerosis in humans. However, studies examining mechanisms underlying diabetes-accelerated atherosclerosis have been limited by the lack of suitable humanoid animal models. Pigs have a cardiovascular system that is very similar to that of humans and is useful as a model for human physiology and pathophysiology. In this study, we established a new miniature pig model for studying dyslipidaemia and atherosclerosis in diabetes. Chinese Guizhou minipigs were fed a normal control diet or a high-fat/high-sucrose diet (HFSD) for 6 months. Plasma total cholesterol (TC), high-density lipoprotein cholesterol, triglyceride (TG), insulin and glucose were quantified at monthly intervals. The induction of insulin resistance and dysfunction of the pancreatic ,-cell were assessed by oral glucose tolerance test and insulin sensitivity test. The aortic fatty streak lesions were quantified following lipid staining with Sudan IV. During the feeding period, mild high plasma TC and TG were induced. At the end of 6 months, in HFSD-fed animals, the adipocytes were hypertrophic, fat deposit in the liver was observed, loss of pancreatic ,-cells was observed, and the aortic fatty streak lesions were clearly present in the animals' aortas. Our study established that miniature pigs that were fed a HFSD without adding dietary cholesterol developed insulin resistance, mild diabetes and atherosclerotic lesions. HFSD-fed miniature pigs may be good animal models for research on the treatment of diabetic dyslipidaemia complicated with atherosclerosis. [source] The influence of dietary fish oil vs. sunflower oil on the fatty acid composition of plasma cholesteryl-esters in healthy, adult catsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 11-12 2003E. A. Plantinga Summary The question addressed was whether the fatty acid composition of plasma cholesteryl esters (CEs) in cats reflects the intake of fatty acids. Diets containing either fish oil or sunflower oil were fed to six healthy, adult cats in a cross-over trial. The dry cat foods contained approximately 18.5% crude fat, of which two-third was in the form of the variable oil. Blood samples were collected at the end of each 4-week feeding period, and the fatty acid composition of plasma CEs and plasma concentrations of lipoproteins were determined. Consumption of the diet with fish oil was associated with significantly greater proportions of eicosapentaenoic acid, arachidonic acid, , -linolenic acid, oleic acid, palmitic acid and myristic acid in plasma CEs. The intake of fish oil instead of sunflower oil reduced the percentage of linoleic acid in CEs. The plasma concentrations of total cholesterol, high-density lipoprotein cholesterol, phospholipids and triglycerides were not affected by fish oil vs. sunflower oil feeding. [source] Influence of the dietary potassium content on transepithelial potassium transport in rat jejunumJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3 2000R. Cermak Summary In a recent study, we found that the distal rat jejunum is able to secrete K+ under in vitro conditions. The question therefore arises as to whether the small intestine might participate in K+ homeostasis. Consequently, this study examined the influence of the dietary K+ content on transepithelial K+ transport in rat jejunum. Rats were fed two diets differing in K+ content (control diet 4.0 g K+/kg, low K+ diet (LK) 0.27 g K+/kg). After a minimal feeding period of 7 days, distal jejunal sheets were mounted in Ussing chambers and unidirectional 86Rb+ fluxes (as a marker for K+ transport) were measured under short-circuit conditions. Jejunum obtained from rats fed the control diet showed a net K+ secretion of 200 nmol Rb+/h/cm2. Unidirectional Rb+ fluxes were smaller in distal jejunum from rats fed the LK diet. In these tissues, glucose-induced short-circuit current and tissue conductance were also smaller than in controls. However, net Rb+ fluxes were not significantly different in small intestine from K+ -restricted rats compared with jejunum from control animals. Based on the observation that the dietary K+ content does not affect transepithelial net K+ transport, we conclude that transcellular K+ secretion by the small intestine is not involved in K+ homeostasis. [source] Nesting behavior and breeding success of HoatzinsJOURNAL OF FIELD ORNITHOLOGY, Issue 4 2007Antje Müllner ABSTRACT Hoatzins (Opisthocomus hoazin) are the only member of the family Opisthocomidae and are found only in forests in the Amazon and Orinoco river basin of South America. Although locally common in riparian habitats, information about their natural history is based almost exclusively on observations from gallery forests in the "llanos" (savannahs) of Venezuela. We investigated the nesting activities of Hoatzins in a primary rainforest in Amazonian Ecuador from 1995 to 2000. At our study site, Hoatzins live and breed in the inundated forests that surround lakes and river channels. Egg laying occurred from February to July and from September to November, but always peaked in April, May, and June. The mean clutch size was 2.4 ± 1.1 eggs (N= 291; range = 1,7), but 51% of all clutches contained two eggs. The mean duration of the incubation period was 32 ± 1.5 d (N= 20) and, overall, 17% of Hoatzin nests fledged at least one young. The main cause of nest failure was predation, with birds and snakes being the most frequent predators. Hoatzin reproduction was closely linked to the rainy season, and such timing may be influenced by increased food availability (high water levels cause leaf fall and the subsequent growth of new leaves coincides with the beginning of the feeding period of the young) and reduced risk of nest predation by mammalian predators when water levels are high. Our results indicate that the breeding biology of Hoatzins in tropical rainforest habitat, including small clutch sizes and low annual reproductive success, is similar to that of tropical passerines and provides further support for the existence of typical life history characteristics for tropical birds. SINOPSIS Las hipótesis relacionadas con la variación altitudinal en los ciclos de vida de aves están basadas en una gran cantidad de datos de aves de zona templada, mientras que para el trópico inclusive se desconoce la biología básica. Esto aplica en particular para aves que no son paserinos. Investigamos las actividades de anidamiento de Hoatzin (Opisthocumus hoazin) en un bosque pluvial primario de la amazonia ecuatorial. En nuestra área de estudio, los hoatzines viven y se reproducen en bosques inundados que bordean lagos y canales. Los intentos reproductivos estuvieron asociados a la época de lluvias y se agruparon en unos meses del año. Normalmente, estas aves anidan una vez al año. El reanidamiento solo ocurrio cuando hubo pérdidas durante la época de puesta. Los nidos fueron construidos en los árboles y arbustos más comunes en el hábitat. El número de huevos por camada vario de uno a siete, aunque el 51% de las camadas consistieron de dos huevos. El tiempo promedio de incubación fue de 32 días. El exito promedio de eclosionamiento (para todos los nidos) fue de 34% y el 50% de los pichones dejaron el nido, lo que dio un éxito de anidamiento en general de 17%. La causa principal de pérdida de nidos lo fue la depredación, en donde otras aves y culebras resultaron ser los principales depredadores. La pequeña ventana de tres meses para reproducirse parece ser el resultado de un fuerte constreñimiento para una reproducción exitosa, debido a una mejor protección de los nidos y mayor abundancia de alimentos durante la época de inundación. El hoatzin exhibe un ciclo de vida similar al de paserinos tropicales. Esto indica la efectividad de las presiones ambientales de selección que deben estar envueltas en la formación de dichos trasos. [source] Effect of sampling interval and temperature on the accuracy of food consumption estimates from stomach contentsJOURNAL OF FISH BIOLOGY, Issue 1 2005A. G. Finstad The effect of temperature and sampling interval on the accuracy of food consumption estimates based on stomach contents was studied using simulation. Three temporal patterns of feeding were considered (scattered throughout the day, one 5 h period or two 5 h periods) and gastric evacuation was modelled according to published values. Sampling intervals of 3 h gave reasonable food consumption estimates (2 to 19% error) at all temperatures. Comparably, sampling intervals as large as 12 h gave reasonable estimates of food consumption (1 to 20% error) when temperature was set to ,10° C. At temperatures <5° C, even 24 h intervals (equivalent to one daily sampling) provided reasonable estimates of daily food consumption (2 to 19% error) for all but the highest gastric evacuation rate combined with one daily feeding period (47% error). The temperature effect on estimation error resulted from diminishing temporal fluctuations in stomach contents with slower gastric evacuation rates. It follows that sampling effort may be considerably minimized when estimating food consumption from stomach contents during periods with low temperatures such as the winter time experienced by temperate fishes. [source] Relating the ontogeny of functional morphology and prey selection with larval mortality in Amphiprion frenatusJOURNAL OF MORPHOLOGY, Issue 6 2010Justin Anto Abstract Survival during the pelagic larval phase of marine fish is highly variable and is subject to numerous factors. A sharp decline in the number of surviving larvae usually occurs during the transition from endogenous to exogenous feeding known as the first feeding stage in fish larvae. The present study was designed to evaluate the link between functional morphology and prey selection in an attempt to understand how the relationship influences mortality of a marine fish larva, Amphiprion frenatus, through ontogeny. Larvae were reared from hatch to 14 days post hatch (DPH) with one of four diets [rotifers and newly hatched Artemia sp. nauplii (RA); rotifers and wild plankton (RP); rotifers, wild plankton, and newly hatched Artemia nauplii (RPA); wild plankton and newly hatched Artemia nauplii (PA)]. Survival did not differ among diets. Larvae from all diets experienced mass mortality from 1 to 5 DPH followed by decreased mortality from 6 to 14 DPH; individuals fed RA were the exception, exhibiting continuous mortality from 6 to 14 DPH. Larvae consumed progressively larger prey with growth and age, likely due to age related increase in gape. During the mass mortality event, larvae selected small prey items and exhibited few ossified elements. Cessation of mass mortality coincided with consumption of large prey and ossification of key elements of the feeding apparatus. Mass mortality did not appear to be solely influenced by inability to establish first feeding. We hypothesize the interaction of reduced feeding capacities (i.e., complexity of the feeding apparatus) and larval physiology such as digestion or absorption efficiency contributed to the mortality event during the first feeding period. J. Morphol., 2010. © 2010 Wiley-Liss, Inc. [source] Circadian variation of portal, arterial and venous blood levels of melatonin in pigs and its relationship to food intake and sleepJOURNAL OF PINEAL RESEARCH, Issue 1 2000G.A. Bubenik Circadian levels of melatonin were determined in the hepatic portal vein, cranial vena cava, and the lower aorta of ten juvenile pigs. Blood was sampled every hour for a total of 24 hr via temporary cannulas introduced into blood vessels under anesthesia. No peak levels of melatonin were found in the mid-scotophase, but hepatic portal concentrations peaked at 06.00 hr. Overall levels of melatonin were highest in the hepatic portal vein (range 35,65 pg/mL), followed by an artery (range 30,55 pg/mL) and the vena cava (range 25,35 pg/mL). Levels of melatonin exhibit strong variation between individual pigs, but generally the average levels from all three sources follow each other's time course. However, on occasion, melatonin levels in the hepatic portal vein varied independently from the levels in the vena cava. Large portal peaks were usually preceded by a feeding period and were associated with a subsequent period of sleep. The data indicate that: 1) there is no clear circadian rhythm of melatonin in the peripheral blood of pigs, 2) relatively little melatonin is metabolized during the first liver passage, 3) food intake may elevate melatonin levels in the hepatic portal vein, and 4) increased levels of melatonin originated in the gastrointestinal tract may induce sleep. [source] Early Alteration in Leukocyte Populations and Th1/Th2 Function in Ethanol-Consuming MiceALCOHOLISM, Issue 8 2001Shawn Starkenburg Background: Chronic alcohol consumption polarizes the immune response away from Th1-mediated cell-mediated immunity. In the present report we investigate the first onset of alteration in immune parameters during ethanol consumption in terms of changes in splenic leukocyte cellularity and surface phenotype as well as alterations in Th1 and Th2 function. Methods: BALB/c and C57BL/6 mice were fed ethanol-containing liquid diets, were pair-fed an isocaloric liquid control diet, or were fed solid diet and water ad libitum for up to 12 days. At intervals during the feeding period, splenic leukocytes were assessed for phenotypic markers by flow cytometry and for their ability to support antigen-induced interferon-, (IFN,) production in a coculture system. Mice were bled at intervals throughout the feeding period, and serum immunoglobin E (IgE) and alcohol levels were determined. Results: Data show that phenotypic and functional alterations occur within the first few days of alcohol consumption. Both liquid diets affect splenic cellularity, and by dietary day 5, ethanol-containing liquid diets further reduce B and NK cell numbers. The decline in B cells is accompanied by a concomitant decline in the amount of major histocompatibility complex class II expressed on this population. Functional alteration in Th1-mediated IFN, production occurred in the population fed ethanol-containing liquid diets by dietary day 5. Th2 function, as indicated by systemic serum IgE levels in these unimmunized mice, is increased by dietary day 6 to 8 and correlated with significant blood alcohol levels. Conclusions: Ethanol consumption by mice causes a rapid decrease in splenic cellularity accompanied by a decrease in Th1 function and a rapid increase in systemic IgE levels. [source] The Effects of Dietary Yeast Culture or Short-chain Fructo-oligosaccharides on the Intestinal Autochthonous Bacterial Communities in Juvenile Hybrid Tilapia, Oreochromis niloticus,×Oreochromis aureus,JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2009Zhi-Gang Zhou The effects of dietary yeast culture (YC) or short-chain fructo-oligosaccharides (FOS) on intestinal autochthonous bacterial communities in juvenile hybrid tilapia, Oreochromis niloticus,×Oreochromis aureus, were studied by 16S rDNA denaturing gradient gel electrophoresis (DGGE). Ninety Tilapias in tanks (10 fish per tank) were randomly and equally divided into three groups. At the end of an 8-wk feeding period of CK (the control treatment), YC (3 g/kg), or FOS (1 g/kg), autochthonous gut bacteria were analyzed in intestinal samples of all fish in each tank of a recirculating aquaculture system. The clear differences in the banding patterns indicated the obvious effects of dietary prebiotics on intestinal communities in hybrid tilapia. Higher variation was detected within the dietary YC group. This difference might be due to the effects of certain immune-stimulating agents in YC on the immunity response of hybrid tilapia. It was concluded that dietary prebiotics, YC, and FOS obviously affected the intestinal bacterial community in hybrid tilapia with different patterns for different kinds. [source] Immune Response and Resistance to Stress and Edwardsiella ictaluri Challenge in Channel Catfish, Ictalurus punctatus, Fed Diets Containing Commercial Whole-Cell Yeast or Yeast SubcomponentsJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2007Thomas L. Welker Dietary supplementation of yeast or yeast subcomponents (YYS) as commercial preparations of ,-glucan (MacroGard®; Biotec-Mackzymal, Tromsø, Norway; and Betagard A®; Aqua-In-Tech, Inc., Seattle, WA, USA), mannan oligosaccharide (Bio-MosÔ Aqua Grade; Alltech, Nicholasville, KY, USA), or whole-cell Saccharomyces cerevisiae (Levucell SB20®; Lallemand Animal Nutrition, Milwaukee, WI, USA) at the manufacturer's recommended levels was evaluated on the physiological performance of juvenile channel catfish, Ictalurus punctatus. Fish were fed YYS diets for 4 wk, followed by 2 wk of control diet. Fish were sampled at the end of each feeding period (4 and 6 wk) to measure hematological and immune parameters and growth and to determine the effects of dietary ,-glucan on resistance to Edwardsiella ictaluri infection and to low-water stress (6 wk). Supplementation of YYS in diets did not affect growth performance, hematology, or immune function. Survival from E. ictaluri infection was from 5 to 17.5% higher in fish fed YYS diets than in the control group, but the increases were not significant. Some improvement in stress resistance was observed in YYS-fed catfish after exposure to low-water stress. Stress reduction in fish fed diets supplemented with yeast subcomponents has been reported previously, but thus far, no explanation has been proposed for this effect. The present study and the previously published research suggest that dietary YYS supplementation does not appear to improve resistance of channel catfish to E. ictaluri. [source] The importance of early complementary feeding in the development of oral tolerance: Concerns and controversiesPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 5 2008Susan L. Prescott Rising rates of food allergies in early childhood reflect increasing failure of early immune tolerance mechanisms. There is mounting concern that the current recommended practice of delaying complementary foods until 6 months of age may increase, rather than decrease, the risk of immune disorders. Tolerance to food allergens appears to be driven by regular, early exposure to these proteins during a ,critical early window' of development. Although the timing of this window is not clear in humans, current evidence suggests that this is most likely to be between 4 and 6 months of life and that delayed exposure beyond this period may increase the risk of food allergy, coeliac disease and islet cell autoimmunity. There is also evidence that other factors such as favourable colonization and continued breastfeeding promote tolerance and have protective effects during this period when complementary feeding is initiated. This discussion paper explores the basis for concern over the current recommendation to delay complementary foods as an approach to preventing allergic disease. It will also examine the growing case for introducing complementary foods from around 4 months of age and maintaining breastfeeding during this early feeding period, for at least 6 months if possible. [source] Experimental study on the toxicity of imidacloprid given in syrup to honey bee (Apis mellifera) coloniesPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 2 2005Jean-Paul Faucon Abstract Two groups of eight honey bee colonies were fed with two different concentrations of imidacloprid in saccharose syrup during summer (each colony was given 1 litre of saccharose syrup containing 0.5 µg litre,1 or 5 µg litre,1 of imidacloprid on 13 occasions). Their development and survival were followed in parallel with control hives (unfed or fed with saccharose syrup) until the end of the following winter. The parameters followed were: adult bee activity (number of bee entering the hive and pollen carrying activity), adult bee population level, capped brood area, frequency of parasitic and other diseases, mortality, number of frames with brood after wintering and a global score of colonies after wintering. The only parameters linked to feeding with imidacloprid-supplemented saccharose syrup when compared with feeding with non-supplemented syrup were: a statistically non-significant higher activity index of adult bees, a significantly higher frequency of pollen carrying during the feeding period and a larger number of capped brood cells. When imidacloprid was no longer applied, activity and pollen carrying were re-established at a similar level for all groups. Repeated feeding with syrup supplemented with imidacloprid did not provoke any immediate or any delayed mortality before, during or following the next winter, whereas such severe effects are described by several French bee keepers as a consequence of imidacloprid use for seed dressing in neighbouring cultures. In any case, during the whole study, mortality was very low in all groups, with no difference between imidacloprid-fed and control colonies. Further research should now address several hypotheses: the troubles described by bee keepers have causes other than imidacloprid; if such troubles are really due to this insecticide, they may only be observed either when bees consume contaminated pollen, when no other sources of food are available, in the presence of synergic factors (that still need to be identified), with some particular races of bees or when colonies are not strong and healthy. Copyright © 2004 Society of Chemical Industry [source] Developmental changes in the patterns of feeding in fourth- and fifth-instar Helicoverpa armigera caterpillarsPHYSIOLOGICAL ENTOMOLOGY, Issue 4 2000D. Raubenheimer Summary Data are presented for developmental changes in feeding behaviour within and across the fourth and fifth stadium of Helicoverpa armigera (Lepidoptera, Noctuidae) caterpillars fed nutritionally homogeneous semi-synthetic foods. We recorded the microstructure of feeding over continuous 12-h periods on consecutive days throughout the two stadia, and in one experiment recorded continuously for 21 h. Larvae in the two stadia showed the same general pattern of macro-events in feeding, including a similar duration of post-ecdysis fast, which was usually broken by consumption of the exuviae, and then a sustained period in which discrete meals on the experimental food were taken regularly. There were, however, some distinct differences in the patterns of meal-taking both between stadia and across different one-third time segments within stadia. Considering between-stadium differences, the proportion of time spent feeding differed significantly only in the last segment of the feeding period of the two stadia, with the value for the fourth-instar larvae being substantially greater than for fifth-instar larvae. As regards within stadium changes, the proportion of time feeding increased from the first to the second segment of both stadia. However, whereas the proportion of time feeding increased from the second to the final segment of the fourth stadium, it decreased across the same period in the fifth stadium. These patterns of changes in the proportion of time feeding within and between stadia, and their behavioural mechanisms (combination of meal durations and meal frequencies), can be explained only partially with reference to increasing food requirements with development. Three areas are identified where further study might help elucidate the reasons for the observed developmental changes in the microstructure of feeding: allometric constraint, the dynamic links between ingestion and post-ingestive processing, and ecological factors such as predation. [source] Atlantic salmon (Salmo salar) postsmolts adapt lipid digestion according to elevated dietary wax esters from Calanus finmarchicusAQUACULTURE NUTRITION, Issue 1 2009A.S. BOGEVIK Abstract Wax esters (WE) in copepods constitute huge natural marine lipid resources, which can contribute as future lipid source in formulated diets in aquaculture, and thereby reduce the pressure on use of marine resources at higher trophic levels. The present study was undertaken to investigate factors affecting WE digestibility, including production of bile and lipases in Atlantic salmon fed diets containing high proportions of oil derived from copepods. Individually tagged postsmolt Atlantic salmon (initial weight 250 g) were distributed into three dietary groups in triplicate tanks and fed either a fish oil supplemented diet or diets where 50% or 100% of the fish oil was replaced with oil extracted from Calanus finmarchicus. WE accounted for 30.7% or 47.7% of the lipids in these latter diets, respectively. Over the 100 day feeding period, the salmon fed the fish oil diet displayed a significantly higher specific growth rate (SGR; 0.74) than fish fed the 100%Calanus oil diet (SGR; 0.67). The apparent digestibility coefficient of total lipid and total fatty acids was significantly higher in salmon fed the fish oil and the mixed diet compared to fish fed the pure Calanus oil diet. However, the fish appeared to enhance the lipid digestive capacity by increasing bile volume and the lipolytic activity. It is concluded that the digestion of WE in Atlantic salmon is poorer than for triacylglycerols. However, the digestive capacity is increased by elevating the bile content and lipase activity. At very high levels however, WE of lipid between 37.5% and 47.7%, are there no more compensation and WE utilisation decreases. [source] Dietary lysine requirement of juvenile gilthead seabream Sparus aurata L.,AQUACULTURE NUTRITION, Issue 1 2006P.A. MARCOULI Abstract The dietary lysine requirement of juvenile gilthead seabream was determined by the growth response of duplicate groups of fish (3.5 g initial weight) fed on six isonitrogenous (427 g kg,1) and isolipidic (135 g kg,1) diets containing graded levels of crystalline l -lysine HCl, with dietary lysine content ranging from 36.3 to 79.7 g kg,1 of protein. The final indispensable amino acid profile of the diets except for lysine was formulated so as to resemble that of wild seabream whole body. Except for the reduced growth performance of fish groups fed the lysine-deficient diets no other deficiency signs were apparent. Survival observed throughout the feeding period of 6 weeks was excellent. Weight gain (in %), specific growth rate, feed efficiency and daily protein deposition (DPD) were significantly improved in response to the increasing levels of dietary lysine up to 52.7 g kg,1 of protein and remained nearly constant thereafter. Whole-body protein content followed a similar pattern as growth parameters in relation to dietary lysine level. Non-linear regression analysis of DPD against dietary lysine level using the four-parameter saturation kinetic model indicated a lysine requirement of 50.4 g kg,1 of protein for this species to support growth. [source] Dietary selenium requirement for juvenile cobia, Rachycentron canadum L.AQUACULTURE RESEARCH, Issue 10 2010Kang Liu Abstract A 10-week feeding trial was conducted to estimate the optimum dietary selenium (Se) requirement for juvenile cobia, Rachycentron canadum L. The basal diet was formulated to contain 50.6% crude protein from vitamin-free casein, gelatin. A control diet (no added seleno- dl -methionine) and five experimental diets containing 0.20, 0.40, 0.60, 0.80 and 1.00 mg seleno- dl -methionine kg,1 were prepared. Each diet was randomly fed to triplicate groups of juvenile cobia with initial weight 6.27±0.03 g in a flow-through system. The Se concentration in rearing water was monitored during the feeding period, and was not detectable. The dietary Se level significantly influenced the survival, specific growth rate (SGR), feed efficiency and the Se concentrations in the whole body and vertebra of cobia. The Se-dependent glutathione peroxidase (EC 1.11.119) activity increased with an increase in the dietary Se levels (P<0.05). Hepatic glutathione reductase (EC 1.6.4.2) activity was the highest in fish fed the diet with 0.21 mg Se kg,1, and declined with an increase in the dietary Se levels. Based on broke-line regression of SGR, the Se concentration in the whole body and vertebra, the Se requirements of juvenile cobia were 0.788, 0.811 and 0.793 mg Se kg,1 diet in the form of seleno- dl -methionine respectively. [source] Effect of feed restriction on the growth performance of turbot (Scophthalmus maximus L.) juveniles under commercial rearing conditionsAQUACULTURE RESEARCH, Issue 8 2010Isidro Blanquet Abstract Two trials were performed to study the effect of periodic feed deprivation (trial 1) or feed restriction, followed by satiation feeding (trial 2) on the growth performance of turbot juveniles under commercial rearing conditions. In trial 1, duplicate groups of 350 fish with an initial weight of 62 g were fed a commercial diet to apparent visual satiation for 7, 6, 5 or 4 days a week for 83 days. At the end of the trial, fish weight was directly related to the number of feeding days but feed efficiency and protein efficiency ratio were not affected by treatments. At the end of the trial, there were no differences in whole-body composition among groups. In trial 2, duplicate groups of 500 fish with an initial weight of 33 g were fed a commercial diet to satiation (100%) or feed restricted to 90%, 80% and 70% of satiation for 90 days. Thereafter, all groups were fed to satiation for 34 days. During the feed restriction period, growth was directly related to feed intake, while during the satiation feeding period, it was inversely related to the previous feeding level. At the end of the trial, the final weight was not different among groups. At the end of the feed restriction period, whole-body lipid content showed a trend to decrease with an increase in the feed restriction level. The results of this study indicate that under practical conditions, turbot juveniles should be fed daily as even cycles of short periods of feed deprivation negatively affect growth, while not improving feed efficiency. On the contrary, even after a relatively long feed restriction period, fish shows compensatory growth, and this may be used as a feed management strategy for controlling fish production in commercial farms. [source] Effects of dietary prebiotics on the growth, feed efficiency and non-specific immunity of juvenile red drum Sciaenops ocellatus fed soybean-based dietsAQUACULTURE RESEARCH, Issue 3 2010J Alejandro Buentello Abstract Previous work has demonstrated several benefits of dietary prebiotics for fish. Here, we report the effects of added dietary fructooligosaccharide (FOS), mannanoligosaccharide (MOS), transgalactooligosaccharide (TOS) and GroBiotic® -A (GBA) on the weight gain, feed efficiency and non-specific immunity of juvenile red drum fed soybean meal (SBM)-based diets, in brackish water at 25 ± 1 °C. Test diets incorporated FOS, MOS, TOS or GBA at 10 g kg,1 in place of cellulose in a basal diet with 40% crude protein, half from SBM and half from fishmeal. After a 4-week feeding period, experimental fish were challenged by exposure to Amyloodinium ocellatum, after which growth and survival were monitored for 2 more weeks. Feed efficiency, serum lysozyme and intracellular superoxide anion production were significantly (P<0.05) enhanced by prebiotic supplementation. Likewise, survival after A. ocellatum exposure was significantly higher for fish fed GBA, MOS and TOS (87%, 84% and 78%) versus 58% for fish fed either the FOS or the basal diet. Taken together, these results indicate that inclusion of several prebiotics at 10 g kg,1 of the diet is adequate to improve the feed efficiency of red drum as well as to enhance disease protection. [source] Functional response of Ameca splendens (Family Goodeidae) fed cladocerans during the early larval stageAQUACULTURE RESEARCH, Issue 14 2009Fabiola Peña-Aguado Abstract We studied the functional response of the goodeid Ameca splendens, an endangered species from rivers Ameca and Teuchitlán (Jalisco, Mexico), from birth until 8 weeks old. The cladocerans, Alona glabra adults, Simocephalus vetulus neonates, Ceriodaphnia dubia adults, Daphnia pulex juveniles and Moina macrocopa adults were used as prey. The prey densities, depending on the species, ranged between 0.25, 0.5, 1.0, 2.0, 4.0, 6.0, 8.0, 16.0 and 32 ind. mL,1, with four replicates at each density. We found that all functional responses were Type II. During the feeding period of 30 min, the fish larvae consumed about 600 individuals of the smallest prey A. glabra (450 ,m). The consumption of larger prey (<1.0 mm) such as S. vetulus, C. dubia, D. pulex and M. macrocopa ranged between 150 and 200 prey larva,1 during the feeding trials. Our study shows that A. splendens reached maximal prey consumption at around 4 weeks of age, after which there was no increase in prey consumption during the feeding period with age until the end of the study period of 8 weeks. Our study indicates that prey digestion rather than handling time determines the functional response in this fish species and that M. macrocopa is most suited as live food for A. splendens. [source] Blood and haemoglobin meal as protein sources in diets for gilthead sea bream (Sparus aurata): effects on growth, nutritive efficiency and fillet sensory differencesAQUACULTURE RESEARCH, Issue 10 2008Silvia Martínez-Llorens Abstract Two parallel experiments were conducted to evaluate the effect of partial substitution of fish meal by two different animal protein sources, blood meal (B) and haemoglobin meal (H) at 0, 50 and 100 g kg,1 of level inclusion in diets for gilthead sea bream, considering a long feeding period for juveniles (Trial 1) and a short feeding period (Trial 2) for on-growing fish. In Trial 1, 33 g juveniles were fed for 242 days and the fish fed with 5% and 10% of haemoglobin dietary inclusion obtained less growth, although feed efficiency, protein efficiency ratio and muscle composition were similar in all diets. In Trial 2, 179 g initial weight fish were fed for 164 days and growth of fish fed H10 showed the lowest growth, although nutrient efficiency and muscle composition were not affected significantly. The results of these experiments demonstrated that blood meal can substitute fish meal (up to 10%) with no effect on performance, but may lead to sensory differences compared with fish fed diet 0, while the inclusion of 5% blood meal had no effect on growth or sensory characteristics. Fish fed 10% haemoglobin inclusion had the poorest growth values. [source] | |||||||||||||||||||||||||||||||