Growth differences of male and female Göttingen minipigs during ad libitum feeding: a pilot study

Even though minipigs have been used in biomedical research for nearly half a century now, no specific nutrient requirements are available. For that reason a series of studies into the nutrient requirements of G?ttingen minipigs were carried out. Firstly, a pilot study was carried out to determine the ad libitum feed intake (FI) during growth, as a reference for later feed restriction studies. Four male and four female minipigs were fed two types of diet, one standard pig diet (20.6% crude protein; 11.7% crude fat; 13.5 mJ/kg DM metabolizable energy) and one diet specially designed for minipigs (12.0% crude protein; 2.9% crude fat; 11.9 MJ/kg DM metabolizable energy). When fed ad libitum for 13 weeks, female G?ttingen minipigs developed a significantly (P<0.05) higher body weight (BW) than males (27.4 vs 16.6 kg) on either diet. The large difference in growth between male and female G?ttingen minipigs did not appear to be the result from differences in metabolizable energy intake. Metabolizable energy intake of male and female G?ttingen minipigs could be predicted by ME=1877 kJxBW(0.61). Both male and female G?ttingen minipigs became obese when fed ad libitum, defined by relative backfat thickness. Relative backfat thickness ranged from 5 to 13 cm/100 kg. Females had thicker relative backfat layers than males. Remarkably, no large changes in haematology and clinical chemistry occurred in ad libitum fed G?ttingen minipigs as compared to reference values, and no abnormalities other than enlarged fat reserves were observed at necropsy. Apparently, G?ttingen minipigs do not restrain FI voluntarily, and restricted feeding is therefore indicated to prevent obesity.     

Variations in gastric acid secretion during periods of fasting between two species of shark

Vertebrates differ in their regulation of gastric acid secretion during periods of fasting, yet it is unknown why these differences occur. Elasmobranch fishes are the earliest known vertebrates to develop an acid secreting stomach and as such may make a good comparative model for determining the causative factors behind these differences. We measured gastric pH and temperature continuously during periods of fasting in captive free-swimming nurse sharks (Ginglymostoma cirratum) using autonomous pH/temperature data-loggers. All nurse sharks secreted strong gastric acids (minimum pH 0.4) after feeding; however, for most of the sharks, pH increased to 8.2-8.7, 2-3 days after feeding. Half of the sharks also exhibited periodic oscillations in pH when the stomach was empty that ranged from 1.1 to 8.7 (acid secretion ceased for 11.3 +/- 4.3 h day(-1)). This is in contrast to the gastric pH changes observed from leopard sharks (Triakis semifasciata) in a previous study, where the stomach remains acidic during fasting. The leopard shark is a relatively active, more frequently feeding predator, and continuous acid secretion may increase digestive efficiency. In contrast, the nurse shark is less active and is thought to feed less frequently. Periodic cessation of acid secretion may be an energy conserving mechanism used by animals that feed infrequently and experience extended periods of fasting.     

Growth performance and body composition in response to dietary protein and lipid levels in Nile tilapia (Oreochromis niloticus Linnaeus, 1758) subjected to normal and temporally restricted feeding regimes

A factorial experiment was designed to examine the effect on compensatory growth (CG) of Nile tilapia Oreochromis niloticus fed diets containing different protein and lipid levels under normal and temporally restricted feeding regimes. Four diets were formulated to contain either 30% or 36% crude protein, and 5% or 11% crude lipid. Triplicate replicates of each treatment were assigned to 24 150‐L tanks (20 fish/tank density). Fish (mean initial weight ± SD = 8.79 ± 0.34 g) were then fed either the normal feeding regime (thrice daily to apparent satiation) or the restricted regime (1 day feed deprivation followed by 3 days of feeding to apparent satiation) over a 44‐days study period. Fish receiving a diet under the restricted regime achieved weight gains (WG) comparable to fish consuming the diet containing 30% protein and 5% lipids under the normal feeding regime. Fish maintained on the restricted feeding regime exhibited reduced feed intake (FI), WG, feed efficiency ratio (FE), protein efficiency rate (PER) and hepatosomatic index versus fish on the normal feeding regime, except WG in fish fed the diet with 30% protein and 5% lipids. However, the resultant FI (85%~94%) was higher than the excepted 75% intake when fish were subjected to the restricted regime. Feeding 11% lipid diets led to improved FI, WG, FE, and PER compared to feeding the 5% lipid diets. Increased FI, WG, and FE, but reduced PER were observed in fish fed with 36% protein versus fish fed 30% protein. Fish receiving the 36% protein diets had lower whole‐body moisture and ash contents, but elevated whole‐body protein and lipid contents compared to those receiving the 30% protein diets. Whole‐body moisture contents were lower, but whole‐body protein, lipid and ash contents were higher in fish fed 11% lipid diets than in fish fed 5% lipid diets. There was an increase in whole‐body moisture content, but a decrease in protein and lipid content in response to the restricted feeding regime. Ash content was not affected by the feeding regime. The present study shows that Nile tilapia fed diets subjected to a restricted feeding regime exhibited growth comparable to those fed the diet at 30% protein and 5% lipid levels under a normal feeding regime. This positive effect was more pronounced in diets at a high protein level or in a combination of high protein and lipid levels.     

Digestive proteinases of Brycon orbignyanus (Characidae,Teleostei): characteristics and effects of protein quality

Juvenile piracanjuba, Brycon orbignyanus, in the wild consume protein from both plant and animal sources. Digestion of protein in piracanjuba begins in the stomach with pepsin, at low pH, and is followed by hydrolysis at alkaline pH in the lumen of the intestine. The digestive system in piracanjuba was evaluated to characterize the enzymes responsible for the digestion of feed protein and their composition. The gastric tissue synthesizes pepsin and the intestine tissues trypsin and chymotrypsin. Operational variables were evaluated and defined for future studies of the digestive system physiology. The enzymatic activity in the intestine and the relative concentration of enzymes were heavily influenced by the composition of the feed and the feeding regime, as detected by substrate-SDS-PAGE. Piracanjuba possess a mechanism of enzyme adaptation responding to food quality and regime, by varying the amount and composition of digestive proteases. This is a requisite study to determine the enzymes digesting protein in food and their characteristics and to gain some clues about the possible regulation mechanisms of enzyme synthesis in piracanjuba.     

A radiographic estimation of the effect of temperature on gastric emptying time in Sarotherodon niloticus (L) × S. aureus (Steindachner) hybrids

A radiographic technique was used to determine temperature effects on gastric emptying time in S. niloticus/aureus hybrids. Stomach evacuation times for 30 g fish fed 3% of their body weight were 8.5 h at 30° C, 10.8 h at 25° C and 16.4 h at 20° C. Hence, there was a negative correlation between stomach evacuation time and temperature. The Q ₁₀ between 20 and 30° C was calculated to be 1.92. Similar relationships were found for intestinal evacuation and total evacuation.
The data were used to estimate maximum daily feed intake levels of fish within the size range studied. Levels for 30 g fish were 8.5% body weight at 30° C, 6.6% at 25° C and 4.4% at 20° C. However, the optimum feeding regime should take account of the feeding behaviour of the animals.     

Feeding and masticatory structures of selected Anomura (Crustacea)

Seven species representing the three superfamilies of the Anomura were studied regarding food, feeding mechanisms, and masticating ossicles of the gastric mill in order to determine whether the structure of the gastric mill was determined by diet or phylogeny. The hippid representative and both porcellanids examined feed on suspended detritus and plankton while the pagurids feed on a variety of substances ranging from detritus to motile prey. The morphology of the mouthparts and chela are related to feeding activity, especially the hippid and porcellanids, but general features of feeding requiring specific anatomical characters were not found in the paguridae. Feeding similarity was measured using the overlap measure of Horn.Among the species the masticating ossicles of the gastric mill differ in those species feeding primarily on detritus; it is finely toothed or setose with the masticating portions of the ossicles blunt. The gastric mill of the species feeding on macromaterial is strongly toothed and sparcely setose, with the masticating portions sharp and cutting. The structure of the gastric mill was found to be influenced by both diet and phylogeny, but the effect of diet appears to be more important.     

小型猪营养需要量研究（1） 体重、采食量、体组成及营养需要相关资料分析

在大量查阅国内外小型猪、普通商品猪有关营养饲养方面资料的基础上,本文总结了小型猪各个阶段的体重、生长速度、采食量、猪体化学成分及其沉积量、日粮赖氨酸能量比等相关数据,为计算小型猪各阶段的营养素需要量提供基础参数。     

Effect of feeding frequency on the daily rhythms of acidic digestion in a teleost fish (gilthead seabream)

Gilthead seabream is a fish species of great importance in Mediterranean aquaculture, attracting many studies on nutrition and chronobiology, although nothing is known about the effect of feeding frequency on the daily rhythms of the gastric digestion process. In this article, we investigated daily rhythms in stomach fullness, gastric and intestine pH, as well as pepsin activity and expression of pepsinogen and proton pump in juvenile fish under three different feeding protocols: (A) one daily meal at 9:00, (B) two daily meals at 9:00 and 17:00 and (C) continuous feeding during the daytime. The results revealed that feeding protocol affected significantly the rhythm of gastric pH and the pepsin activity pattern. The gastric pH exhibited significant daily rhythms in the three cases with the acrophase located at night in the regimes A and B and during daytime, in the regime C. In the regimes A and B, the pepsin activity peaked few hours after the meals, although the afternoon meal in B produced a higher peak. In the regime C, the peak occurred in the middle of the feeding period. Lowest total pepsin activity was observed in regime A, and the highest activity with the regime C. In contrast, the pepsinogen gene expression remained low along the daily cycle, with an expression peak just before or after the morning meal in regimes A and C, respectively. The proton pump gene expression was also practically constant with a peak right after the morning meal in the regime C. On the other hand, intestinal pH showed a postprandial increase after the first morning meal in all the three treatments, recovering the resting values in the dark period. Two meals and continuous feeding allowed a better and prolonged gastric digestion and consequently the juveniles exhibited better growth with the same daily ration of food. In short, while the gastric digestion pattern is mainly driven by pH changes induced by the time of food ingestion, the regulation of the intestinal digestion seems to be more independent of the feeding protocol.     

Helicobacter pylori and Clinical Aspects of Gastric Cancer

In spite of important new insights into the basic mechanisms of gastric carcinogenesis, progress in the management of gastric cancer has been modest. Some modifications in the chemotherapies used for palliation and strategies for downstaging of the disease prior to surgical intervention are noteworthy. The positive experience with endoscopic mucosal resection (EMR) and submucosal dissection (ESD) for treatment of early gastric cancer has been confirmed and extended. The procedure-related morbidity and post-interventional quality of life is clearly favorable compared to open surgical resection in well-selected patients. New data on Helicobacter pylori revealed that eradication after endoscopic resection of early gastric cancer significantly reduces the incidence of recurrent and metachronous gastric neoplasias. It can further improve healing rates of treatment induced gastric ulcers. Eradication therapy therefore remains the best target for prevention of the disease. Critical is the "point of no return" when mucosal alterations (i.e. intestinal metaplasia, glandular atrophy) are no longer reversible. A population-based screen-and-eradicate strategy for H. pylori infection can at present only be recommended in high incidence regions.     

实验用小型猪营养需要研究进展

随着小型猪实验动物化研究的不断进步,小型猪作为生命科学研究的实验动物越来越受到人们的重视,因此生产标准化的小型猪至关重要,而对小型猪营养需要的了解和饲料标准的制定是生产标准化小型猪的重要基础之一。本文就小型猪的国内、外品种,小型猪的消化代谢特点以及对能量、蛋白质、矿物质及粗纤维营养需要的研究进展进行综述。     

Physiological correlates of growth and condition in the yellow perch (Perca flavescens)

This study on yellow perch (Perca flavescens) examines a series of enzymatic markers and the relative weights of pyloric caeca and visceral lipids, their response to changes in feeding regime and their potential use to infer recent changes in growth rate and fish condition. Fish were exposed to four different feeding regimes for 12 weeks resulting in specific growth rates ranging from 0.3% to 3.5% (%/day). Growth and condition responded rapidly to changes in ration and the weight of pyloric caeca and visceral lipids reflected increased feed intake. Growth rate was correlated with muscle citrate synthase and caecal nucleoside-diphosphate kinase activities, whereas condition was correlated with muscle citrate synthase and lactate dehydrogenase activities and with caecal glucose-6-phosphate dehydrogenase activity. Results showed that enzyme activities and biometric parameters responded rapidly to increased feed intake, but the response was slower when food intake decreased. Plateaus were attained for both condition and visceral lipid index, but the relative weight of pyloric caeca continued to increase throughout the experimental period. Results from this study could, in principle, be used to infer recent growth and energy status in wild yellow perch and thus provide an indicator of food availability in their environment.     

Phosphate feeding to permit growth while maintaining secondary product synthesis

Summary Maintaining high metabolic activities for extended periods by feeding small amounts of the growth limiting nutrient was examined for the production of cycloheximide by Streptomyces griseus. Batch studies indicated that increased initial phosphate levels led to increased cell concentrations, stimulated glucose utilization, and over a limited range (<0.6 g/l KH₂PO₄) did not adversely affect cycloheximide production rates. Semi-continuous phosphate feeding was observed to permit limited cell growth, and to enhance metabolic activities (i. e. glucose utilization). The effect of semi-continuous phosphate feeding on antibiotic production depended on the feed rate, with high feed rates suppressing production.     

Influence of probiotic feeding duration on disease resistance and immune parameters in rainbow trout

The effect of feeding the probiotic Kocuria SM1 to rainbow trout (Oncorhynchus mykiss, Walbaum) on disease resistance was evaluated. Thus, rainbow trout were fed Kocuria SM1 supplemented diets at concentrations of 10⁸ cells g⁻¹ feed for up to four weeks, and then challenged intraperitoneally with Vibrio anguillarum at weekly intervals. A two-week feeding regime led to the maximum reduction in mortalities, i.e. 16%, compared to mortalities of 62, 30 and 22% for one, three and four week feeding regimes, respectively. These compared to 70–90% mortalities of the controls. An enhanced cellular and humoral immune response, notably greater head kidney macrophage phagocytic and peroxidase activities, and higher serum lysozyme and total protein levels were recorded after two weeks of probiotic administration. These results reveal that a two-week feeding regime with Kocuria SM1 leads to higher disease protection in rainbow trout, with protection linked to stimulation of immune parameters.     

Growth and physiological changes during metamorphosis of Senegal sole reared in the laboratory

The metamorphosis of Solea senegalensis was studied in larvae reared at 20° C and fed four different feeding regimes. A, Artemia (4 nauplii ml⁻¹); B, Artemia (2 nauplii ml⁻¹); C, mixed diet (2 nauplii ml⁻¹ and 3 mg ml⁻¹ microencapsulated diet); and D, microencapsulated diet (3·7 mg ml⁻¹). Rotifers were also supplied in all cases during the first days of feeding. These feeding regimes supported different growth rates during the pre-metamorphosis period (regime A, G=0·376 day⁻¹; regime B, G=0·253 day⁻¹; regime C, G=0·254 day⁻¹; regime D, G=0·162 day⁻¹). Larvae started metamorphosis 9 days after hatching (DAH) when fed the regime A, 13 DAH with regime B, 11 DAH with regime C and 15 DAH with regime D. A minimum 5·6–5·9 mm L_T was required under all feeding regimes to initiate the metamorphosis. Eye translocation was completed when the larvae reached 8·6–8·7 mm L_T (regimes A, B and C), but only 7·3 mm L_T with regime D. 4·4–6·2 days were required to complete eye migration under the regimes A, B and C, and 18·3 days under the regime D. This transformation is concomitant with changes in body reserves, and with the pattern of some digestive enzymes.     

Survival and reproduction when food is scarce: implications for a lekking Hawaiian Drosophila

Abstract.  1. In insects, larval diet can have a major impact on development, survival, and reproductive success. However, resource availability at the adult phase of the life cycle is also likely to have strong effects in species where there is an extended period of sexual maturation following adult eclosion.
2. The effect of diet on the survival and reproductive success of the lekking Hawaiian fruit fly, Drosophila grimshawi , was explored. Two generations of emerging adults were exposed to one of two feeding regimes: 'constant' and 'varied' (corresponding to food 'each day' or 'every other day' respectively). The impact of resource availability on survival and reproductive success in each generation was then investigated.
3. The probability of survival to 5 weeks old was higher for individuals fed a constant diet than individuals fed a varied diet, but was comparable for males and females.
4. There was a significant maternal effect on offspring survival. Offspring whose mothers were reared on a constant feeding regime had higher survival than offspring whose mothers were reared on a varied diet.
5. There was no relationship between feeding regime and the quantity of pheromones deposited by males (a measure of male reproductive investment); however F₂ sons were more likely to deposit pheromones and deposited a larger quantity of pheromone than their F₁ sires. The number and sex ratio of offspring (a measure of female reproductive effort) emerging from the F₁ generation was unrelated to maternal or paternal feeding regime.
6. The implications of variation in the foraging environment for mate choice in D. grimshawi are discussed.     

Effects of dietary fats on red blood cell membrane insulin receptor in normo- and hypercholesterolemic miniature swine

It has been demonstrated that the type of dietary fat affects insulin receptors in various tissues in normal humans and animals by altering membrane fluidity. This study compares the effects of n-3 fatty acids from fish oil and n-6 fatty acids from corn oil on red blood cell membrane insulin receptors in normal and hypercholesterolemic minipigs. A group of minipigs were made hypercholesterolemic by feeding cholesterol and lard for 2 months; the other group served as controls and was fed stock diet. Both groups were then fed experimental diets containing either corn oil or menhaden oil or a mixture of the two for 23 additional weeks. Blood was collected at 0, 2, 12 and 23 weeks after the start of the experimental diets and membranes were prepared from the red blood cells. Insulin binding to red blood cell membranes was measured by radioreceptor assay. Plasma insulin was measured by radioimmunoassay. Insulin binding to red blood cell membrane was compared with the fluidity of the membrane measured and reported earlier. There was no significant effect of cholesterol feeding on plasma insulin concentrations. After 23 weeks on experimental diet plasma insulin was significantly higher in minipigs fed menhaden oil compared to those fed corn oil. No such effect was observed in hypercholesterolemic minipigs. No significant effect of either hypercholesterolemia or fish oil was observed on red blood cell insulin binding. A significant negative relationship was observed between insulin binding and anisotropy at 4°C for all probes but at 37°C significant negative relationship was observed only with polar probes. The data suggest that n-3 fatty acids from fish oil significantly increases plasma insulin in minipigs compared to n-6 fatty acids from corn oil. However, the unsaturation has no significant effect on insulin receptors on erythrocytes. Similarly, prior hypercholesterolemic state also has no effect on plasma insulin levels or the insulin binding to red blood cell membranes.     

Involvement of pericardial adipose tissue in cardiac fibrosis of dietary-induced obese minipigs— Role of mitochondrial function

BackgroundHeart is a high energy demand organ and cardiac fat is the main local energy source for heart. Alteration in cardiac fat may affect cardiac energy and contribute to heart dysfunction. We previously observed a link between alteration in pericardial fat (PAT) and local adverse effects on myocardial fibrosis in obese minipigs. This study investigated the role of PAT on cardiac energy and mitochondrial function, and elucidated a potential mechanism for PAT in cardiac fibrosis.Materials and methodsFive-month-old Lee-Sung minipigs were made obese by feeding a high-fat diet (HFD) for 6 months. The conditioned medium from PAT of obese minipigs (PAT-CM) was collected and H9C2 cells were treated with it to study mechanisms.ResultsHFD caused a cardiac energy deficit and fibrosis in the left ventricle. An elevated content of IL6 and malondialdehyde was found in the PAT of obese pigs. Obese pigs exhibited an increased level of oleic acid and a reduced level of saturated fatty acids in PAT compared to control pigs. HFD did not alter the metabolic characteristics of epicardial fat. PAT-CM caused apoptosis of H9C2 cells and inhibited basal mitochondrial respiration and ATP production. Protein expressions for mitochondrial dynamics- (Mfn2, Opa1, Drp1, and Fis1) and a mitophagy-related protein (Parkin) were suppressed by PAT-CM. PAT-CM enhanced the protein expression of LC3II, and the ratio of LC3II/LC3I.To conclude, PAT was involved in cardiac fibrosis of HFD-fed minipigs. The secretomes of PAT impaired mitochondrial functions and caused cardiomyocyte apoptosis in a paracrine manner.     

Feeding activity and opercular pressure transients in Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis> L.): application to feeding management in fish farming

Ecological and economical sustainability of marine aquaculture operations depend on proper feeding management. Feed wastage from overfeeding is a source of pollution, represents futile use of precious marine resources, and undermines the economic viability of operations. Additionally, underfeeding reduces growth and fish welfare. Finding an optimal feeding regime in terms of temporal and spatial distribution of the feed ration require intimate knowledge of the individual feeding behaviour of fish sustaining intensive culturing conditions. Fish telemetry has proved to be a valuable tool for studying spatial behaviour in sea cages, however there are currently no practical methods available with respect to detection of actual feed intake in fish on the individual level. The present study investigates pressure transients arising in the opercular cavity of farmed Atlantic salmon (Salmo salar L.) in connection with feeding, and whether such measurements can serve as an indication of feed ingestion. A technical solution to the sensing problem based on a differential pressure transducer is presented along with typical pressure signal traces obtained during feeding in a hard wire tank experiment. Measurements showed considerable variation of sub-ambient pressure transients (1.5 kPa ± 0.95) and their duration (519 ms ± 117), suggesting that the fish modulates its strike intensity depending on the particular feeding situation. Despite variations in scale, opercular pressure waveforms have distinct structural features that repeat between feeding instants. From a signal processing point of view waveforms provide sufficient information with respect to isolation and detection of feeding incidents, which is important with respect to a potential implementation of the sensing principle in a telemetry tag design. Issues regarding development and application of a telemetry system based on this sensing principle are discussed.     

Exploring the emergence of a biojet fuel supply chain in Brazil: An agent‐based modeling approach

The aviation industry accounts for more than 2% of global CO₂ emissions. Biojet fuel is expected to make an essential contribution to the decarbonization of the aviation sector. Brazil is seen as a key player in developing sustainable aviation biofuels owing to its long‐standing experience with biofuels. Nevertheless, a clear understanding of what policies may be conducive to the emergence of a biojet fuel supply chain is lacking. We extended a spatially explicit agent‐based model to explore the emergence of a biojet fuel supply chain from the existing sugarcane–ethanol supply chain. The model accounts for new policies (feed‐in tariff and capital investment subsidy) and new considerations into the decision making about production and investment in processing capacity. We found that in a tax‐free gasoline regime, a feed‐in tariff above 3 R$/L stimulates the production of biojet fuel. At higher levels of gasoline taxation (i.e., 2.46 R$/L), however, any feed‐in tariff is insufficient to ensure the production of biojet fuel. Thus, at these levels of gasoline taxation, it is needed to introduce regulations on the production of biojet fuel to ensure its production. Given the current debate about the future direction of the biofuel policy in Brazil, we recommend further research into the effect of market mechanisms based on greenhouse gas emissions on the emergence of a Brazilian biojet fuel supply chain.     

Scanning Electron Microscopy of Stomatogenesis Accompanying Conjugation in Euplotes aediculatus*

SYNOPSIS. The succession of morphologic changes in the feeding apparatus (peristome) accompanying conjugation and postconjugant development in the hypotrich Euplotes aediculatus has been examined by scanning electron microscopy (SEM). The details of stomatogenesis inferred from earlier light-microscopic studies of silver-stained preparations have been confirmed and extended. The elaborate peristome is the dominant surface feature of vegetative Euplotes. In conjugation, the ciliates are joined in their peristomial regions; as the conjugants separate, the old feeding apparatus is seen to be disrupted and partially resorbed. In its place is the crescent-shaped primordium of a new peristome, which develops as part of a general cortical reorganization. This primordium expands anteriorly, unfurling a new crown of ciliary membranelles that soon replaces the remaining preconjugant membranellar band. The resulting “exconjugant peristome'’is characterized by a greatly reduced number of adoral membranelles and the absence of paroral membranelles, buccal cavity, and cytostome. Exconjugants thus cannot feed for 2–3 days, until the missing peristomial components are replaced. This occurs by means of a 2nd cortical reorganization, during which new membranelles, developing from another peristomial rudiment, are added directly to the abbreviated exconjugant set. A new buccal cavity is concurrently sculpted as the primordial depression enlarges, and the cells can resume feeding sometime during the 4th day after separation. The implications of this mode of stomatogenesis and the nonfeeding condition are discussed, as are the advantages of SEM for studies of ciliate morphogenesis.