Effects of dopaminergic system activation on feeding behavior and growth performance of the sea bass (Dicentrarchus labrax): A self-feeding approach

Dopamine is synthesized from l-dopa and subsequently processed into norepinephrine and epinephrine. Any excess neurotransmitter can be taken up again by the neurons to be broken down enzymatically into DOPAC. The effect of dopamine on mammalian food intake is controversial. Mice unable to synthesize central dopamine die of starvation. However, studies have also shown that central injection of dopamine inhibits food intake. The effect of dopaminergic system in the fish feeding behavior has been scarcely explored. We report that the inclusion of l-dopa in the diets results in the activation of sea bass central dopaminergic system but also in the significant increase of the hypothalamic serotonin levels. Dietary l-dopa induces a decrease of food intake and feed conversion efficiency that drives a decline of all growth parameters tested. No behavioral effects were observed after l-dopa treatment. l-dopa treatment stimulated central expression of NPY and CRF. It suggests that CRF might mediate l-dopa effects on food intake but also that CRF neurons lie downstream of NPY neurons in the hierarchical forebrain system, thus controlling energy balance. Unexpectedly, dietary administration of haloperidol, a D₂-receptor antagonist, cannot block dopamine effects but also induces a decline of the food intake. This decrease seems to be a side effect of haloperidol treatment since fish exhibited a decreased locomotor activity. We conclude that oral l-dopa inhibits sea bass food intake and growth. Mechanism could also involve an increase of hypothalamic serotoninergic tone.     

Late‐moulting Black‐necked Grebes Podiceps nigricollis show greater body mass in the face of failing food supply

From August to December, thousands of Black‐necked Grebes Podiceps nigricollis concentrate during the flightless moult period in salt ponds in the Odiel Marshes, southern Spain, where they feed on the brine shrimp Artemia parthenogenetica. We predicted that because Black‐necked Grebes moulted in a food‐rich, predator‐free environment, there would be no net loss of body mass caused by the use of fat stored to meet energy needs during remigial feather replacement (as is the case for some other diving waterbirds). However, because the food resource disappears in winter, we predicted that grebes moulting later in the season would put on more body mass prior to moult because of the increasing risk of an Artemia population crash before the moult period is completed. Body mass determinations of thousands of birds captured during 2000–2010 showed that grebes in active wing‐moult showed greater mass with date of capture. Early‐moulting grebes were significantly lighter at all stages than late‐moulting birds. Grebes captured with new feathers post‐moult were significantly lighter than those in moult. This is the first study to support the hypothesis that individual waterbirds adopt different strategies in body mass accumulation according to timing of moult: early‐season grebes were able to acquire an excess of energy over expenditure and accumulate fat stores while moulting. Delayed moulters acquired greater fat stores in advance of moult to contribute to energy expenditure for feather replacement and retained extra stores later, most likely as a bet hedge against the increasing probability of failing food supply and higher thermoregulatory demands late in the season. An alternative hypothesis, that mass change is affected by a trophically transmitted cestode using brine shrimps as an intermediate host and Black‐necked Grebes as final host, was not supported by the data.     

Evaluation of pretreatment methods for lignocellulosic ethanol production from energy cane variety L 79-1002

Approximately half of the 80 billion tons of crop produced annually around the world remains as residue that could serve as a renewable resource to produce valuable products such as ethanol and butanol. Ethanol produced from lignocellulosic biomass is a promising renewable alternative to diminishing oil and gas liquid fuels. Sugarcane is an important industry in Louisiana. The recently released variety of “energy cane” has great potential to sustain a competitive sugarcane industry. It has been demonstrated that fuel-grade ethanol can be produced from post harvest sugarcane residue in the past, but optimized ethanol production was not achieved. Optimization of the fermentation process requires efficient pretreatment to release cellulose and hemicellulose from lignocellulosic complex of plant fiber. Determining optimal pretreatment techniques for fermentation is essential for the success of lignocellulosic ethanol production process. The purpose of this study was to evaluate three pretreatment methods for the energy cane variety L 79-1002 for maximum lignocellulosic ethanol production. The pretreatments include alkaline pretreatment, dilute acid hydrolysis, and solid-state fungal pretreatment process using brown rot and white rot fungi. Pretreated biomass was enzymatically saccharified and subjected to fermentation using a recombinant Escherichia coli FBR5. The results revealed that all pretreatment processes produced ethanol. However, the best result was observed in dilute acid hydrolysis followed by alkaline pretreatment and solid-state fungal pretreatment.     

Temperaturverlauf und Gärfutterqualität unter verschiedenen Silodecken im Flachsilo

Observations were carried out of actual acidity, volatile fatty acid (VFA) concentrations, enzyme activity in the rumen, total protein, urea, total lipid and glucose in the serum of conventional (CL) and gnotobi‐otic lambs (GL) in the period of milk nutrition. The inoculum of gnotobiotic iambs contained Streptococcus bovis, Prevoxella ruminicola, Butyrivibrio fibrisolvens and Selenomonas ruminantium at a concentration of 1.10⁶ each. Throughout the observation period the pH of the rumen contents of gnotobiotic lambs ranged within 6.5–6.8 with a significant difference at an age of 7 weeks. Total VFA concentrations in the rumen contents were increased in the CL throughout milk nutrition; the differences at 4 and 5 weeks of age were significant. Total VFA in the conventional lambs revealed an increasing tendency between weeks 4 and 7, reaching higher levels at 7 weeks of age (57.1 mmol.l"¹), whereas in the gnotobiotic animals the range (24.3–30.1 mmol.l"¹) was narrow and the peak occurred at 6 weeks of age. In GL significantly increased molar proportions of acetic acid were observed whereas in CL the molar proportions of propionic acid proved to be significant increased. The molar proportions of butyric and valeric acids were increased in CL but the group differences were not significant. In GL no isoacids were found. Alpha amylase (E.C.3.2.1.1.) activity of the rumen contents was significantly increased in GL between weeks 2 and 6 of age whereas cel‐Iulase (endoglucanase E.C.3.2.1.4. and cellobiohydrolase E.C.3.2.1.91.) activity was significantly increased in 4‐week‐old CL. Over the whole period of milk nutrition no significant differences were observed in ure‐ase (E.C.3.5.1.5.) activity of the rumen contents in the examined groups.

At 5 weeks of age significantly increased total protein levels were observed in the conventional animals with maximum levels occurring at 4 weeks of age (CL‐59.5 g.l"¹ GL‐55.3 g.l"¹). Urea levels in 6‐week old conventional lambs were significantly higher than in the gnotobiotic animals (CL‐6.4 mmol.l"’ vs. GL‐1.9 mmol.l"¹). As to glycaemia no significant group differences were recorded. In the conventional animals total lipid levels were significantly increased at 1 and 6 weeks of age with a peak occurring in the first week of life (7.5 g.l"¹) whereas in the gnotobiotic lambs a significant increase was observed at 3 weeks of age, the peak being recorded in 4 week‐old animals (4.3 g.l"¹). Throughout the period of interest the mean daily weight gains in the conventional and gnotobiotic lambs presented 0.164 and 0.162 kg, respectively. The functional development of the rumen was significantly influenced by the complexity of the microfiora.     

Chemische Untersuchungen über unterschiedlich vorbehandelte Federmehle

Abstract

Dr. Carlheinrich Engelmann: Ernährung und Fütterung des Geflügels. Erschienen im Neumann-Verlag Radebeul/Berlin, 162 Seiten, 17 × 24 cm Halbleinen, MDN 6,80. Reviewed by H. Bergner

Dr. Martin Pankrath: Wasserbedarf landwirtschaftlicher Nutztiere — Mengennormen. - Erschienen im S. Hirzel Verlag, Leipzig C 1, Schuhmachergäßchen 1–3. 1. Auflage 1963, 99 Seiten mit 25 Diagrammen, 21 Tabellen und 2 Tafeln im Text. 8°, Hln., MDN 10,70. Reviewed by H. Bergner

Physiologische und wirtschaftliche Leistungsgrenzen in der Tierzucht 14 Vorträge eines internationalen Symposions im Max-Planck-Institut für Tierzucht und Tierernährung in Mariensee vom 14. bis 17. Oktober 1963.: Herausgegeben von M. Witt. 315 Seiten mit 8 Kunstdrucktafeln. Englische Summaries. Steif broschiert, Preis DM 16,-. Bestellung über Institut. Reviewed by H. Bergner     

Digestive and metabolic utilization of lauric,myristic and stearic acid in cows,and associated effects on milk fat quality

A study was carried out to examine the effect of dietary supplementation of oregano essential oil on performance of broiler chickens experimentally infected with Eimeria tenella at 14 days of age. A total of 120 day-old Cobb-500 chicks separated into 4 equal groups with three replicates each, were used in this study. Two groups, one infected with 5·10⁴ sporulated oocysts of E. tenella and the other not, were given a basal diet and served as controls. The other two groups also infected with E. tenella were administered diets supplemented with oregano essential oil at a level of 300 mg/kg, or with the anticoccidial lasalocid at 75 mg/kg. Following this infection, survival rate, bloody diarrhoea and oocysts excretion as well as lesion score were determined. Throughout the experimental period of 42 days, body weight gain and feed intake were recorded weekly, and feed conversion ratios were calculated. Two weeks after the infection with E. tenella supplementation with dietary oregano oil resulted in body weight gains and feed conversion ratios not differing from the non-infected group, but higher than those of the infected control group and lower than those of the lasalocid group. These parameters correspond with the extent of bloody diarrhoea, survival rate, lesion score and oocyst numbers and indicated that oregano essential oil exerted an anticoccidial effect against E. tenella, which was, however, lower than that exhibited by lasalocid.     

Effect of a soy protein diet on protein and energy metabolism and organ development in protein-restricted growing pigs

Two feeding experiments were carried out with castrated male pigs weighing between 10 and 30 kg to study acute and persisting dietary effects on growth and on protein and energy metabolism in growing pigs. Pigs were fed semi-synthetic isoenergetic and isonitrogenous diets at 50% protein requirement with either soy protein isolate (SPI) or casein (CAS) as sole protein source. Intake of protein and ME amounted to 9% w/w and 1800 kJ · kg BW ^{? 0.62} · d ^{? 1} in Exp. 1, respectively, and 9% w/w and 1430 kJ · kg BW ^{? 0.62} · d ^{? 1} in Exp. 2. The CAS diet was supplemented by Lys, Met, Thr and Trp. In Exp. 1 (acute effects), 18 pigs received the CAS diet for 24 days (period 1); 9 pigs were then switched to a SPI diet whereas 9 pigs continued on the CAS diet for another 31 days (period 2). In Exp. 2, a third period of 31 days was added in which the SPI group was switched back to CAS diet. The control group was fed on the CAS diet throughout Exp. 2 (86 days). Altogether the majority of parameters were not affected neither comparing SPI with CAS in Exp. 1 nor inspecting possible persistence of effects in Exp. 2. In detail, in Exp. 1 SPI compared to CAS feeding resulted in a lower efficiency of protein utilisation and lower protein retention. Attendant upon the lower protein retention an increased energy retention as fat was only observed in tendency. SPI feeding caused a decreased body weight, thyroid weight and increased hepatic carbohydrate content that persisted after the diet was changed back to CAS (Exp. 2).     

Estimation of net nutrient oxidation and lipogenesis in growing pigs

Data from previous series of trials were reevaluated in order to quantify the net nutrient oxidation and lipogenesis by combining data from balance experiments and indirect calorimetry measurements. The experiments were carried out with eight castrated males of Danish Landrace measured individually from 30 to 100 kg BW. All pigs were fed alternately on high feeding level, near ad libitum and on low feeding level, near maintenance. Oxidation of carbohydrate (OXCHO) and fat (OXF) was calculated from gas exchange measurements. On high feeding level the contribution from OXCHO and OXF to the total heat production was 55 and 30%, respectively, at 30 kg BW and fairly constant from 60 kg BW with OXCHO around 80% and no net OXF. At low feeding level the contribution from OXCHO and OXF was 28 and 63%, respectively, at 30kg BW, increasing to 52% for OXCHO and decreasing to 37% for OXF at 95 kg BW. The lipogenesis on high feeding level increased from 2.4 to 11.9 MJ/d, while on low feeding level it increased from 2.5 to 3.6 MJ/d at 30 to 95 kg BW. The intake of carbohydrate was too low to cover energy requirement by OXCHO on low feeding level and in the first periods on high feeding level and OXF occurred. In spite of a deficit of carbohydrate for oxidation a part of carbohydrate (2.6 MJ/d, ～ 150 g/d) was used for fat synthesis, indicating an importance of lipogenesis in growing pigs.     

Simulated impact of the renewable fuels standard on US Conservation Reserve Program enrollment and conversion

A socioeconomic model is used to estimate the land‐use implications on the U.S. Conservation Reserve Program from potential increases in second‐generation biofuel production. A baseline scenario with no second‐generation biofuel production is compared to a scenario where the Renewable Fuels Standard (RFS2) volumes are met by 2022. We allow for the possibility of converting expiring CRP lands to alternative uses such as conventional crops, dedicated second‐generation biofuel crops, or harvesting existing CRP grasses for biomass. Results indicate that RFS2 volumes (RFS2‐v) can be met primarily with crop residues (78% of feedstock demand) and woody residues (19% of feedstock demand) compared with dedicated biomass (3% of feedstock demand), with only minimal conversion of cropland (0.27 million hectares, <1% of total cropland), pastureland (0.28 million hectares of pastureland, <1% of total pastureland), and CRP lands (0.29 million hectares of CRP lands, 3% of existing CRP lands) to biomass production. Meeting RFS2 volumes would reduce CRP re‐enrollment by 0.19 million hectares, or 4%, below the baseline scenario where RFS2 is not met. Yet under RFS2‐v scenario, expiring CRP lands are more likely to be converted to or maintain perennial cover, with 1.78 million hectares of CRP lands converting to hay production, and 0.29 million hectares being harvested for existing grasses. A small amount of CRP is harvested for existing biomass, but no conversion of CRP to dedicated biomass crops, such as switchgrass, are projected to occur. Although less land is enrolled in CRP under RFS2‐v scenario, total land in perennial cover increases by 0.15 million hectares, or 2%, under RFS2‐v. Sensitivity to yield, payment and residue retention assumptions are evaluated.     

能谱CT在去除腰椎术后金属伪影中的应用进展

多层计算机断层扫描(Multi-slice computed tomography,MSCT)具有时间及空间分辨率高的特点已经被广泛应用于脊柱术后评价,然而,因为术中植入金属植入物,CT图像由于其成像原理的限制,其图像质量受到金属植入物的严重影响,金属伪影大多来源于量子噪声、散射线和射束硬化效应,降低图像的对比度,使细微解剖结构显示不清,从而使得感兴趣区域的检测能力降低,其图像质量明显下降,甚至使临床医师做出错误的诊断,因此,为了做出更准确的腰椎术后并发症诊断和术后评估,使金属伪影最小化成为关键。能谱CT及其扫描及重建技术可以有效的去除腰椎术后产生的金属伪影,改善图像质量,本文能谱CT在腰椎术后金属伪影去除方面的应用进行综述。