Metabolic evidence of a 'rumen bypass' or a 'ruminal escape' of nutrients in roe deer (Capreolus capreolus)

As short chain fatty acids produced in the forestomach are insufficient to satisfy the energy requirements of the concentrate selecting roe deer (Capreolus capreolus), it is proposed that these animals may have other mechanisms to avoid energy losses due to microbial fermentation. Nutrients bypassing down the ventricular groove (rumen bypass) or ruminal escape of unfermented or partially fermented nutrients may be two alternatives. As metabolic evidence for incomplete fermentation in the forestomach we investigated: (1) the abundance of the sodium-dependent glucose co-transporter (SGLT1) in the duodenum; (2) enzyme activities of maltase, saccharase and alpha-amylase in duodenal and pancreatic tissue; and (3) the proportion of essential, polyunsaturated fatty acids in depot fat samples from ruminants of different feeding type and--for comparison--from animals with a simple stomach. The high abundance of SGLT1, high enzyme activity and the high proportion of polyunsaturated fatty acids in the concentrate selecting ruminants support the hypothesis of rumen bypass or ruminal escape of nutrients in roe deer and reflect differences in nutrient utilization by ruminants that belong to different feeding types.     

A review of nutritional effects on fat composition of animal products with special emphasis on n-3 polyunsaturated fatty acids

The fatty acid composition of animal products (eggs, milk and meat) is the reflect of both the tissue fatty acid biosynthesis and the fatty acid composition of ingested lipids. This relationship is stronger in monogastrics (pigs, poultry and rabbits) than in ruminants, where dietary fatty acids are hydrogenated in the rumen. There is an increasing recognition of the health benefits of polyunsaturated fatty acids (PUFA), because these fatty acids are essential for humans. In addition, the ratio n-6/n-3 fatty acids in the human diet is important. This ratio by far exceeds the recommended value of 5. Therefore, inclusion of fish meals, or n-3 PUFA rich oils, or linseed in animal diets is a valid means of meeting consumer demand for animal products that are nutritionally beneficial.The studies that are undertaken on animals mainly use diets supplemented with linseed, as a source of n-3 fatty acids. The use of linseed diets generally leads to an increased n-3 fatty acid content in animal products (egg, meat, milk) in ruminants and monogastrics. Recent studies have also demonstrated that neither the processing nor the cooking affects the PUFA content of pork meat or meat products.The ability of unsaturated fatty acids, especially those with more than two double bonds, to rapidly oxidise, is important in regulating the shelf life of animal products (rancidity and colour deterioration); however, a good way to avoid such problems is to use antioxidant products (such as vitamin E) in the diet.Some studies also show that it is not necessary to feed animals with linseed-supplemented diets for a long time to have the highest increase in PUFA content of the products. So, short-term diet manipulation can be a practical reality for industry.As the market for n-3 PUFA enriched products is today limited in most countries, other studies must be undertaken to develop this kind of production.     

The conjugate regulation of mammary blood flow and secretory cell metabolism: analysis of problem

In the review the essential features of system regulation of mammary blood flow, substrate supply, uptake and utilization by cellular metabolism and for milk component synthesis are considered, with emphasis on productive ruminants (cows and goats). The conception of local control of regional vascular resistance in described. in which the criterion of maintenance of energetic balance in secretory cells is used. The some steps of substrates utilization and their regulation are described (glucose, acetate, free amino acids, triacylglycerols, free fatty acids). The secretory cell is considered as control unit equilibrating the extraction of substrates from blood with the rate of milk components synthesis. The role of hormonal factors in these processes is discussed.     

Postnatal differential expression of chemoreceptors of free fatty acids along the gastrointestinal tract of supplemental feeding v. grazing kid goats

The gastrointestinal tract (GIT) of animals is capable of sensing various kinds of nutrients via G-protein coupled receptor-mediated signaling transduction pathways, and the process is known as ‘gut nutrient chemosensing’. GPR40, GPR41, GPR43 and GPR119 are chemoreceptors for free fatty acids (FFAs) and lipid derivatives, but they are not well studied in small ruminants. The objective of this study is to determine the expression of GPR40, GPR41, GPR43 and GPR119 along the GIT of kid goats under supplemental feeding (S) v. grazing (G) during early development. In total, 44 kid goats (initial weight 1.35±0.12 kg) were slaughtered for sampling (rumen, abomasum, duodenum, jejunum, ileum, cecum, colon and rectum) between days 0 and 70. The expression of GPR41 and GPR43 were measured at both mRNA and protein levels, whereas GPR40 and GPR119 were assayed at protein level only. The effects of age and feeding system on their expression were variable depending upon GIT segments, chemoreceptors and expression level (mRNA or protein), and sometimes feeding system × age interactions (P<0.05) were observed. Supplemental feeding enhanced expression of GPR40, GPR41 and GPR43 in most segments of the GIT of goats, whereas G enhanced expression of GPR119. GPR41 and GPR43 were mainly expressed in rumen, abomasum and cecum, with different responses to age and feeding system. GPR41 and GPR43 expression in abomasum at mRNA level was greatly (P<0.01) affected by both age and feeding system; whereas their expression in rumen and abomasum at protein level were different, feeding system greatly (P<0.05) affected GPR41 expression, but had no effect (P>0.05) on GPR43 expression; and there were no feeding system×age interactions (P>0.05) on GPR41 and GPR43 protein expression. The expression of GPR41 and GPR43 in rumen and abomasum linearly (P<0.01) increased with increasing age (from days 0 to 70). Meanwhile, age was the main factor affecting GPR40 expression throughout the GIT. These outcomes indicate that age and feeding system are the two factors affecting chemoreceptors for FFAs and lipid derivatives expression in the GIT of kids goats, and S enhanced the expression of chemoreceptors for FFAs, whereas G gave rise to greater expression of chemoreceptors for lipid derivatives. Our results suggest that enhanced expression of chemoreceptors for FFAs might be one of the benefits of early supplemental feeding offered to young ruminants during early development.     

Release of short chain fatty acids from cream lipids by commercial lipases and esterases

Lipases and esterases are frequently used in dairy production processes to enhance the buttery flavour of the end product. Short chain fatty acids, and especially butanoic acid, play a key role in this and different enzymes with specificity towards short chain fatty acids are commercially available as potent flavouring tools. We have compared six lipases/esterases associated with buttery flavour production. Although specificity to short chain fatty acids was ascribed to each enzyme, clear differences in free fatty acid profiles were found when these enzymes were applied on cream. Candida cylindraceae lipase was the most useful enzyme for buttery flavour production in cream with the highest yield of free fatty acids (57 g oleic acid 100 g⁻¹ fat), no release of long chain fatty acids and specificity towards butanoic acid.     

Characterization of critical factors influencing gene expression of two types of fatty acid-binding proteins (L-FABP and Lb-FABP) in the liver of birds

In avian species, two types of intracellular lipid-binding proteins are abundant in the liver, the liver fatty acid-binding protein (L-FABP) and the liver basic fatty acid-binding protein (Lb-FABP). Both FABPs are capable of forming complexes with free fatty acids and bile acids, but the functional distinction between L-FABP and Lb-FABP in avian liver is not fully understood. To gain insights into the functional distinction between L-FABP and Lb-FABP, we investigated the expression of both genes in relation to the pre- and post-hatching development, diurnal cycle and feeding state in the livers of chicken (Gallus gallus) and Japanese quail (Coturnix japonica). In chickens, the Lb-FABP mRNA was expressed only in the liver, while the L-FABP was expressed in both liver and intestinal tissues. Only small amounts of the L-FABP and Lb-FABP mRNAs were detected in the liver during chicken embryogenesis, but at the onset of hatching a dramatic increase in mRNA expression was observed for both genes, suggesting that the expression of the L-FABP and Lb-FABP genes is synchronized at developmental stages. Remarkably, the diurnal expression pattern differed between the two genes under a 16L:8D condition in sexually mature quail: L-FABP gene expression transiently increased at the end of the light cycle, whereas Lb-FABP gene expression peaked during the early part of the light cycle and gradually decreased as the dark period approached. We attempted to identify the factors regulating the diurnal gene expression pattern, and found that feeding stimulation was a critical factor inducing Lb-FABP gene expression irrespective of light condition. On the other hand, feeding stimulation only slightly stimulated expression of the L-FABP gene, and was not always its primary determinant. These results suggest that L-FABP and Lb-FABP play different roles in metabolic process during the postprandial state.     

Rumen prokaryotic communities of ruminants under different feeding paradigms on the Qinghai-Tibetan Plateau

Yak and Tibetan sheep are the major indigenous ruminants on the Qinghai-Tibetan Plateau in China. The aim of this work was to study the differences in ruminal fermentation parameters and rumen prokaryotic community composition between hosts and feeding paradigms. The 16S rRNA genes targeting bacteria and archaea were sequenced using the MiSeq platform. The results showed that the prokaryotic community structure between yak and Tibetan sheep was significantly different (P < 0.01). A significant difference in structure was also found between groups of yaks barn fed with a total mixed ration (TMR) and those naturally grazing (NG) (P = 0.034), as well as for Tibetan sheep of the two groups (P = 0.026). The core prokaryotic populations that existed in the rumen mostly dominated the structure. There was an obvious correlation of the prokaryotic community composition at the phylum and genus levels with the host or the feeding pattern. In addition, Tibetan sheep showed significantly higher yields of volatile fatty acids (VFAs) than yak, as did the NG group compared with the TMR group. In conclusion, both the host and feeding pattern may influence rumen microbial ecology system, with host effects being more important than those of the feeding pattern.     

Fatty acid and alcohol composition of the small polar copepods,Oithona and Oncaea: indication on feeding modes

The fatty acid and alcohol compositions of the Antarctic copepods Oithona similis, Oncaea curvata, Oncaea antarctica and the Arctic Oncaea borealis were determined to provide the first data on their lipid biochemistry and to expand the present knowledge on their feeding modes and life-cycle strategies. All these tiny species contained high amounts of wax esters (on average 51.4–86.3% of total lipid), except females of Oithona similis (15.2%). The fatty-acid composition was clearly dominated by 18:1(n-9), especially in the wax-ester-rich Oncaea curvata (79.7% of total fatty acids). In all species, 16:0 and the polyunsaturated fatty acids 20:5(n-3) and 22:6(n-3), which are structural components of all membranes, occurred in significant proportions. The dominant fatty alcohols were 14:0 and 16:0. In Oncaea antarctica and Oncaea borealis, the 20:1(n-9) and 22:1(n-11) alcohols and, to a lesser extent, the corresponding fatty acids were also found in high proportions. This indicates carnivorous feeding, although de novo biosynthesis cannot be excluded. The variable composition might be due to a wider range of food items and parasitic feeding. Typical trophic marker fatty acids for phytoplankton ingestion occurred only in small amounts, which suggests that the species were feeding on particles such as detritus or aggregates and not on living phytoplankton. From the compositional data of fatty acids and alcohols, it can be concluded that feeding behaviour of all species is omnivorous and/or carnivorous.     

Effect of selected plant species within biodiverse pasture on in vitro fatty acid biohydrogenation and tissue fatty acid composition of lamb

The effect of botanical diversity on supply of polyunsaturated fatty acids (PUFA) to ruminants in vitro, and the fatty acid (FA) composition of muscle in lambs was investigated. Six plant species, commonly grown as part of UK herbal ley mixtures (Trifolium pratense, Lotus corniculatus, Achillea millefolium, Centaurea nigra, Plantago lanceolata and Prunella vulgaris), were assessed for FA profile, and in vitro biohydrogenation of constituent PUFA, to estimate intestinal supply of PUFA available for absorption by ruminants. Modelling the in vitro data suggested that L. corniculatus and P. vulgaris had the greatest potential to increase 18:3n-3 supply to ruminants, having the highest amounts escaping in vitro biohydrogenation. Biodiverse pastures were established using the six selected species, under-sown in a perennial ryegrass-based sward. Lambs were grazed (~50 days) on biodiverse or control pastures and the effects on the FA composition of musculus longissimus thoracis (lean and subcutaneous fat) and musculus semimembranosus (lean) were determined. Biodiverse pasture increased 18:2n-6 and 18:3n-3 contents of m. semimembranosus (+14.8 and +7.2 mg/100 g tissue, respectively) and the subcutaneous fat of m. longissimus thoracis (+158 and +166 mg/100 g tissue, respectively) relative to feeding a perennial ryegrass pasture. However, there was no effect on total concentrations of saturated FA in the tissues studied. It was concluded that enhancing biodiversity had a positive impact on muscle FA profile reflected by increased levels of total PUFA.     

Dietary free fatty acids form alkaline phosphatase-enriched microdomains in the intestinal brush border membrane

Abstract

Free fatty acids released during intralumenal digestion of dietary fat must pass through the enterocyte brush border membrane before triacylglycerol reassembly and subsequent chylomicron delivery to the lymph system. In the present work fluorescent BODIPY fatty acid analogs were used to study this membrane passage in organ cultured intestinal mucosal explants. We found that in addition to a rapid uptake into the cytoplasm, a fraction of the fatty acid analogs were inserted directly into the brush border membrane. Furthermore, a brief exposure of microvillar membrane vesicles to a fat mixture mimicking a physiological solution of dietary mixed micelles, rearranged the lipid raft microdomain organization of the membranes. Thus, the fat mixture generated a low-density subpopulation of microvillar detergent resistant membranes (DRMs) highly enriched in alkaline phosphatase (AP). Since this GPI-linked enzyme is the membrane protein in the brush border with the highest affinity for lipid rafts, this implies that free fatty acids selectively insert stably into these membrane microdomains. We have previously shown that absorption of dietary lipids transiently induce a selective endocytosis of AP from the brush border, and from work by others it is known that fat absorption is accompanied by a rise in serum AP and secretion of surfactant-like particles from enterocytes. We propose that these physiological processes may be triggered by the sequestering of dietary free fatty acids in lipid raft microdomains of the brush border.     

Fatty Acid Activation in Cyanobacteria Mediated by Acyl-Acyl Carrier Protein Synthetase Enables Fatty Acid Recycling

In cyanobacteria fatty acids destined for lipid synthesis can be synthesized de novo, but also exogenous free fatty acids from the culture medium can be directly incorporated into lipids. Activation of exogenous fatty acids is likely required prior to their utilization. To identify the enzymatic activity responsible for activation we cloned candidate genes from Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942 and identified the encoded proteins as acyl-acyl carrier protein synthetases (Aas). The enzymes catalyze the ATP-dependent esterification of fatty acids to the thiol of acyl carrier protein. The two protein sequences are only distantly related to known prokaryotic Aas proteins but they display strong similarity to sequences that can be found in almost all organisms that perform oxygenic photosynthesis. To investigate the biological role of Aas activity in cyanobacteria, aas knockout mutants were generated in the background of Synechocystis sp. PCC 6803 and S. elongatus PCC 7942. The mutant strains showed two phenotypes characterized by the inability to utilize exogenous fatty acids and by the secretion of endogenous fatty acids into the culture medium. The analyses of extracellular and intracellular fatty acid profiles of aas mutant strains as well as labeling experiments indicated that the detected free fatty acids are released from membrane lipids. The data suggest a considerable turnover of lipid molecules and a role for Aas activity in recycling the released fatty acids. In this model, lipid degradation represents a third supply of fatty acids for lipid synthesis in cyanobacteria.Cyanobacteria present a diverse group of Gram-negative bacteria capable of oxygenic photosynthesis (Margulis, 1975). Their two photosystems, as well as other genetic and morphological similarities, identified them as putative predecessors of chloroplasts of eukaryotic plants (Wallace, 1982; Pakrasi, 1995). The structural similarities of cyanobacteria and chloroplasts are reflected in part by equivalence of biochemical pathways and their components. For instance, cyanobacterial fatty acid and glycerolipid compositions closely resemble those of the inner envelope and thylakoid membranes of chloroplasts (Roughan et al., 1980; Heinz and Roughan, 1983). In cyanobacteria, as well as in chloroplasts, fatty acids are synthesized by a type II fatty acid synthase (FAS) complex utilizing a freely dissociable acyl carrier protein (ACP; Froehlich et al., 1990). The products of FAS are released as acyl ACPs and may serve directly as substrates for acyltransferases, incorporating the fatty acids into membrane lipids (Frentzen et al., 1983). The substrate specificity of the acyltransferases establishes in cyanobacteria as well as in plastids the typical prokaryotic fatty acid pattern characterized by C16 fatty acids esterified to the sn-2 position. The correspondence of metabolic pathways between cyanobacteria and chloroplasts is reflected by the shared presence of closely related enzymes that catalyze key reactions. Besides the many similarities, however, there are also clear discrepancies that in part account for the fact that cyanobacteria are unicellular organisms, whereas chloroplasts are embedded in the metabolism of a eukaryotic cell. In terms of lipid metabolism, such differences become obvious if one considers the fact that the plastidial FAS also supplies the extraplastidic compartment with fatty acids (Browse et al., 1986). Fatty acid export from the chloroplast necessitates the release of synthesized acyl chains from ACP to allow transport across both envelope membranes. The release is achieved by the action of acyl-ACP thioesterases that hydrolyze the acyl-ACP thioester to liberate the fatty acid (Voelker et al., 1997). In cyanobacteria such export would obviously result in an unfavorable loss of fatty acids, and consequently homologous proteins to acyl-ACP thioesterases cannot be found here. Whereas cyanobacteria seem to be unable to release fatty acids enzymatically from their activated state, all cyanobacterial genomes available to date encode an activity most likely responsible for the activation of free fatty acids. The respective sequences are annotated as acyl-CoA synthetases. Conserved motifs in the amino acid sequence identify these proteins as members of the well-established superfamily of AMP-binding proteins. This protein family comprises several hundred amino acid sequences spreading across all organisms analyzed so far. The family members are annotated in the PROSITE database under entry number PS00455. Although these predicted fatty acid-activating enzymes of cyanobacteria are annotated as acyl-CoA synthetases due to their sequence similarity to proteins with such enzymatic activity, there is a much higher degree of similarity to certain AMP-binding proteins of plant origin with less-well-established function. These plant proteins are predicted to reside in chloroplasts and one member of this subgroup from Arabidopsis (Arabidopsis thaliana) designated as AAE15 was recently described as acyl-ACP synthetase. The conclusions were based on the comparison of enzymatic activity between plant extracts of wild-type and knockout mutant lines (Koo et al., 2005). Whereas the biological role of this activity remained largely elusive, it was shown that the capacity of plant extracts to elongate supplied medium fatty acids depended on AAE15 activity. Since the elongation of medium chain fatty acids in the plastid depends on the FAS requiring acyl ACPs, it was concluded that the fatty acids must have been activated by ACP. The elongated fatty acids ultimately appeared in membrane lipids. Together these findings suggested that AAE15 is an acyl-ACP synthetase.Besides encoding a protein homologous to AAE15 from Arabidopsis, cyanobacteria are also able to utilize exogenous fatty acids like it was shown for isolated chloroplasts. It is well established that feeding different cyanobacteria with free fatty acids results in the incorporation of these fatty acids into membrane lipids. For this process the activation of the fatty acids is believed to be essential. This causal relationship was clearly shown at least for other unicellular organisms like Escherichia coli and yeast (Saccharomyces cerevisiae) where the deletion of acyl-CoA synthetase activity resulted in the inability to utilize exogenous fatty acids (Overath et al., 1969; Knoll et al., 1995). It is not easy to assess how regularly cyanobacterial cells are exposed to exogenous free fatty acids in nature but at least for marine strains this is most likely a rather artificial situation. Therefore, it can be speculated that the capacity to activate free fatty acids might be of different relevance in the lipid metabolism of cyanobacteria in vivo.In this article, we investigated the fatty acid metabolism of cyanobacteria. We isolated candidate genes potentially encoding enzymes involved in fatty acid activation from the strains Synechocystis sp. PCC 6803 (hereafter Synechocystis) and Synechococcus elongatus PCC 7942 (hereafter Synechococcus) and performed heterologous expression in E. coli. The recombinant proteins were shown to possess acyl-ACP synthetase activity with broad substrate specificity. Knockout mutant strains deficient in acyl-ACP synthetase activity were characterized by secretion of endogenous free fatty acids into the culture medium. Combined with labeling experiments, the results suggest an essential role for acyl-ACP synthetase in fatty acid recycling in cyanobacteria.     

Evolutionary steps of ecophysiological adaptation and diversification of ruminants: a comparative view of their digestive system

Summary A review is made of the ruminant digestive system in its morphophysiological variations and adaptations relating to foraging behaviour, digestive physiology, to interactions between plants and ruminants and to geographic and climatic diversity of ruminants' ecological niches. Evidence is provided for evolutionary trends from an extreme selectivity mainly for plant cell contents and dependence upon a fractionated fore- and hindgut fermentation, to an unselective intake of bulk roughage subjected to an efficient plant cell wall fermentation, mainly in the forestomachs. The review is based on detailed comparative morphological studies of all portions of the digestive system of 65 ruminant species from four continents. Their results are related to physiological evidence and to the classification of all extant ruminants into a flexible system of three overlapping morphophysiological feeding types: concentrate selectors (40%), grass and roughage eaters (25%) and intermediate, opportunistic, mixed feeders (35%). Several examples are discussed how ruminants of different feeding types are gaining ecological advantage and it is concluded that ruminants have achieved high levels of digestive efficiency at each evolutionary stage, (including well-documented seasonal adaptations of the digestive system) and that ruminant evolution is still going on. Deductions made from the few domesticated ruminant species may have, in the past, biased scientific evaluation of the free-ranging species' ecology. The main threat to a continuous ruminant evolution and diversity appears to be man's neglect for essential ecological interactions between wild ruminants and their specific habitats, which he alters or destroys.Abbreviations bw body weight - CS concentrate selector - DFC distal fermentation chamber (distended caecocolon) - GR grass and roughage eater - IM intermediate (mixed) feeder - PFC proximal fermentation chamber (ruminoreticulum/forestomachs) - RR Ruminoreticulum - SCFA Short-chain fatty acis (acetic, butyric, propionic acid set free by rumen bacteriae) - SE Surface enlargement (of absorptive mucosa) Supported by German Research Community grant DFG Ho 273/6Dedicated to Professor Dr. Dr. h.c. Dietrich Starck on the occasion of his 80th birthday     

Utilization of exogenous free fatty acids for the production of very low density lipoprotein triglyceride by livers of carbohydrate-fed rats

High carbohydrate diets enhance the hepatic output of very low density lipoprotein triglycerides. The fatty acids of these triglycerides could come from exogenous sources (i.e., diet or adipose tissue) or from de novo fatty acid synthesis in the liver. The role of exogenous free fatty acids was evaluated in rats fed Purina Chow or diets containing 10% fructose for up to 14 wk. In carbohydrate-fed rats, serum triglycerides were twice normal, and VLDL accounted for about 60% of the increases. Pre-beta-lipoprotein was increased and alpha- and beta-lipoprotein were decreased. Phospholipid and cholesterol levels were unchanged. Livers were perfused with glucose and free fatty acids. Perfusate free fatty acids rose from 180 to 1800 micro eq/liter as the infused acids increased from 0 to 992 micro eq/3 hr; simultaneously, net free fatty acid uptake rose from < 1 to 18 micro eq/g/hr and triglyceride output by the liver doubled. However, rates of secretion of triglyceride became constant, and triglyceride accumulated in liver at uptakes of free fatty acids > 13 micro eq/g/hr. More lauric and myristic acid appeared in the perfusate than was infused, suggesting the hepatic discharge of free fatty acids. Livers of fructose-fed rats secreted twice as much oleate-(14)C-labeled triglyceride as controls at all levels of free fatty acid uptake. The ratios of the specific activities of perfusate triglyceride to free oleate-(14)C were unaffected by diet and were about 0.6 and 1.0 at low and high triglyceride secretion rates, respectively. Thus, carbohydrate feeding did not result in altered uptakes of free fatty acids or preferential secretion of triglycerides containing endogenously synthesized fatty acid. Instead, the increased secretion of triglyceride was accomplished by enhanced formation of VLDL triglyceride from exogenous free fatty acids.     

Characterization of free fatty acid receptors expression in an obesity rat model with high sucrose diet

Introduction/aims: In recent years, it has been shown that free fatty acids receptors (FFAR) of whose function in the cell surface plays a significant role in the regulation of cell function and nutrition as well are activated by various endogenous ligands, but mainly by fatty acids. Within FFAR of our interest are GPR 41, 43 and 120. The functions of these receptors are varied and dependent on the tissue where they are. The activation and signaling of these receptors, FFAR, are involved in many physiological processes, and currently the target of many drugs in metabolic disorders like obesity, diabetes and atherosclerosis.

Material and methods: Obesity was induced with hypercaloric diet (HD) in male Wistar rats for 20?weeks (n?=?10). At the end, adipose tissue (abdominal and subcutaneous) was taken to perform assays for relative quantification mRNA expression by end-point RT-PCR and protein level expression by Western blot.

Results: These present data have shown for the first time that total mRNA isolation and protein expression from both adipose tissues (abdominal and subcutaneous) of rat in obesity condition yield significative statistical difference among the control versus obese groups, showing that the diet high in carbohydrates modifies the total presence of mRNA and protein level expression of the receptors GPR41, 43 and 120.

Conclusions: Further comparative methods are in process to clarify whether or not the obesity changes the functional receptors in these two tissues for new pharmacological approaches.     

Die Messung der Trockensubstanzverluste bei der mit Natriumbenzoat konservierten Zuckerrübensilage mit Hilfe einer Absorptionsapparatur

Two experiments I and II, with 2 and 4 lactating dairy cows respectively, each fistulated with ruminai and duodenal cannulae, were carried out. The effects on milk composition and milk fat fatty acids’ pattern through a continous daily infusion into the duodenum with 6 g nicotinic acid were investigated. Treatments were nicotinic acid (NA) infusion in experiment I, and nicotinic acid infusion plus feeding 270 g of stearic acid in experiment II. No application of NA and stearic acid in experiments I and II respectively, acted as controls.

Nicotinic acid infusion did not significantly influence protein, fat and lactose contents of milk. In both experiments, infusion of nicotinic acid decreased the proportion of short and middle chain fatty acids in milk fat and increased significantly the percentage of oleic acid from 19.0 to 25.4%. The addition of stearic acid alone had no effect on milk composition and fatty acids’ pattern. Additional infusion of nicotinic acid infusion significantly increased nicotinamid concentration in the milk from 49.7 to 87.2 μg/100 ml.     

The role of adipose tissue in mediating the beneficial effects of dietary fish oil

Fish oil improves several features of metabolic syndrome (MetS), such as dyslipidemia, insulin resistance and hepatic steatosis. Fish oil may mediate some of its beneficial effects by modulating the storage and/or secretory functions of adipose tissue (AT). The storage of triglycerides in AT is regulated by the availability of free fatty acids and the degree of lipolysis in AT. Fish oil has been shown to reduce lipolysis in several studies, indicating improved triglyceride storage. Importantly, AT secretes a variety of adipokines and fish oil feeding is associated with remarkable changes in the plasma levels of two key adipokines, adiponectin and leptin. Much attention has been focused on the contribution of adiponectin in fish oil-mediated improvements in MetS. However, emerging evidence also indicates a role of leptin in modulating the components of the MetS upon fish oil feeding. In addition to improving the storage and secretory functions of AT, fish oil, and the n-3 fatty acids found in fish oil, has been shown to reduce inflammation in AT. These effects may be in part a result of activation of peroxisome proliferator-activated receptor γ or inhibition of Toll-like receptor 4. Thus, there is compelling evidence that fish oil mediates its beneficial effects on MetS by improving AT storage and secretory functions and by reducing inflammation.     

Untersuchungen zum Einsatz von ammonisierten Strohpellets als alleinige Grundration in der Wiederkäuerfütterung

Because legumes are a very important feed source for ruminants, the aim of this study was to evaluate the ideal inclusion level of hay Arachis pintoi cv. Belmonte in sheep diets by measuring the dry matter intake (DMI), concentration of volatile fatty acids, ammonia–nitrogen concentration, ruminal pH and the in situ degradability of dry matter (DM) and crude protein (CP). In the experiment with four sheep, a 4 × 4 Latin Square design was used with four periods and four treatments (0%, 30%, 60% and 100% Arachis replacing grass hay). Significant interactions were observed between treatments and sampling times for ammonia–nitrogen and acetate, propionate and butyrate concentration and the acetate:propionate ratio. The ruminal pH and total volatile fatty acids concentration were not affected by interaction between treatments and sampling time. The degradation of DM and CP was similar, rising with the increasing content of Arachis, showing a linear effect. The treatment containing 60% of Arachis showed best results, with good levels of daily weight gain and higher ruminal concentrations of volatile fatty acids. The legume showed high levels of CP, high digestibility and appropriate levels of fibre, with excellent standards of degradation and ruminal characteristics. The use of the legume Arachis for ruminants is a promising option of nutrient supply to meet production demands of these animals.     

Feeding and hemolymph trehalose concentration influence sex pheromone production in virgin Heliothis virescens moths

Previously, we demonstrated that sex pheromone production in mated female Heliothis virescens moths is dependent upon hemolymph trehalose concentration (HTC), which is influenced by activities such as the feeding of adults on sucrose. In this paper we demonstrate, for the first time, that this effect also occurs in starved (i.e., sugar-stressed) virgin females. Females allowed to feed on sugar for 6 days, following eclosion, had significantly greater titers than females that had fed only on water (i.e., were starved). No differences in pheromone titer were observed between sugar- and water-fed females at shorter (1 or 3 days) periods following eclosion. The relatively short-term effects of HTC on sex pheromone titer of virgins, were demonstrated by feeding experiments, in which starved (for 4 days) virgins fed on 10% sucrose solution had significantly greater HTC and pheromone titers than ones fed only on water; an increase in HTC was apparent within an hour, while the increase in pheromone titer was apparent within 2.5 h, of sugar feeding. Starvation also showed similar effects on titers of pheromone gland fatty acids (pheromone intermediates) and HTC. Over 6 days of starvation, fatty acid titers and HTC declined gradually. After feeding on sucrose, titers of hexadecanoic, (Z)-9-hexadecanoic, (Z)-11-hexadecanoic and (Z)-9-octadecanoic, acids, as well as HTC, increased significantly 24 h later, but titers of octadecanoic and (Z,Z)-9,12-octadecanoic (linoleic) acids did not. Lepidoptera cannot biosynthesize polyunsaturated acids, but the lack of change in octadecanoic acid titer suggests this acid may not participate in pheromone biosynthesis. In addition to these short-term changes in pheromone and fatty acid production, mediated by HTC, a longer-term effect of age, regardless of HTC, on pheromone titer was observed. Overall, these results are consistent with hemolymph trehalose and glandular fatty acids acting as twin metabolite reservoirs for pheromone biosynthesis. Hemolymph trehalose, able to be refilled through feeding on exogenous sugars, has a one-way flow of metabolites for synthesis of glandular free fatty acids (FFAs) and pheromone, while glandular glycerolipids provide a reversible reservoir for metabolites, accepting surplus FFAs when glandular concentrations are high, and providing FFAs for pheromone biosynthesis when concentrations are low.     

Linoleic acid, α-linolenic acid,and monolinolenins as antibacterial substances in the heat-processed soybean fermented with Rhizopus oligosporus

ABSTRACT

Antibacterial activities against Staphylococcus aureus and Bacillus subtilis were found in an ethanol fraction of tempe, an Indonesian fermented soybean produced using Rhizopus oligosporus. The ethanol fraction contained free fatty acids, monoglycerides, and fatty acid ethyl esters. Among these substances, linoleic acid and α-linolenic acid exhibited antibacterial activities against S. aureus and B. subtilis, whereas 1-monolinolenin and 2-monolinolenin exhibited antibacterial activity against B. subtilis. The other free fatty acids, 1-monoolein, monolinoleins, ethyl linoleate, and ethyl linolenate did not exhibit bactericidal activities. These results revealed that R. oligosporus produced the long-chain polyunsaturated fatty acids and monolinolenins as antibacterial substances against the Gram-positive bacteria during the fungal growth and fermentation of heat-processed soybean.