Effect of a negative energy balance induced by feed restriction on pro-inflammatory and endoplasmic reticulum stress signalling pathways in the liver and skeletal muscle of lactating sows

High-producing sows develop typical signs of an inflammatory condition and endoplasmic reticulum (ER) stress in the liver during lactation. At present, it is unknown whether a negative energy balance (NEB) is causative for this. Therefore, an experiment with lactating sows, which were either restricted in their feed intake to 82% of their energy requirement (Group FR) or were fed to meet their energy requirement (Control), was performed and the effect on ER stress-induced unfolded protein response (UPR), nuclear factor kappa B (NF-κB), nuclear factor E2-related factor 2 (Nrf2) and NOD-like receptor P3 (NLRP3) inflammasome signalling in the liver was evaluated. Relative mRNA concentrations of several genes involved in ER stress-induced UPR, NF-κB and NLRP3 inflammasome signalling were reduced in the liver of Group FR compared to the Control group. Plasma concentrations of haptoglobin and C-reactive protein were 13% and 37%, respectively, lower in Group FR than in the Control group, but these differences were not significant. In conclusion, feed restriction in lactating sows inhibits pro-inflammatory and ER stress signalling pathways in the liver, which suggests that not the NEB per se is causative for inflammation and ER stress induction in the liver of lactating sows. Rather it is likely that ER stress during lactation is the consequence of the presence of potent pro-inflammatory and ER stress-inducing stimuli, such as cytokines, reactive oxygen species and microbial components, which enter the circulation as a result of infectious diseases that frequently occur in sows after farrowing.     

Effect of N,N-dimethylglycine supplementation in parturition feed for sows on metabolism, nutrient digestibility and reproductive performance

The current pilot study assessed the influence of N,N-dimethylglycine (DMG) on insulin sensitivity, glucose and fat metabolism, nutrient digestibility and reproductive performance of sows in the peripartal period. At day 105 of gestation, 25 sows were randomly assigned to the control (n = 13) or the DMG group (n = 12). Sows from the DMG group were supplemented with 1 g DMG/kg feed until day 3 of lactation. After an overnight fast 1 day after farrowing, a blood sample of each sow was drawn. The plasma was analyzed for insulin, glucose, fructosamine, leptin, thiobarbituric acid reactive substances (TBARS), ferric reducing ability of plasma (FRAP), non-esterified fatty acids (NEFA) and triglycerides (TG) and an oral glucose tolerance test was performed. A rectal feces sample was collected and the apparent fecal digestibility (AFD) of crude fat (CFAT), crude protein (CP) and nitrogen-free extract (NFE) was calculated after proximate analyses. Finally, a colostrum sample was collected from each sow and analyzed for the presence of DMG. Reproductive performance parameters were recorded. The results showed an improvement in the AFD of CFAT, CP and NFE when DMG was supplemented. This beneficial effect confirms the hypothesis that DMG acts as an emulsifying agent. The improvement in digestibility in the DMG group was accompanied by a numerical increase in plasma TG (P = 0.067). Plasma NEFA concentrations were not different between treatment groups. DMG supplementation neither affected glucose clearance nor influenced plasma insulin, glucose, fructosamine or leptin levels. TBARS and FRAP also remained unaffected, despite previously reported anti-oxidative properties of DMG. Furthermore, no significant impact on reproductive performance could be recorded. In conclusion, DMG supplementation significantly improved nutrient digestibility. Possible beneficial effects on energy metabolism and reproductive performance of sows should be tested when DMG is supplemented for a longer period of time or at a higher dose.     

Effect of litter size,milk replacer and housing on production results of hyper-prolific sows

The modern hyper-prolific sow gives birth to more piglets than she has functional teats (in the following called supernumerary piglets). The aim of the present study was (1) to investigate the production consequences of hyper-prolific sows rearing supernumerary piglets equal to the mean live-born litter size, and (2) investigate whether potential negative effects on survival and growth could be alleviated by providing access to milk replacer and/or providing easier access to the udder (by loose housing). At day 1 (D1) postpartum (pp), 93 litters were standardised to 14 or 17 piglets (LS14/LS17) after which no piglets were moved between sows leading to decreased litter size if piglets died. Litters were provided with or without milk replacer in milk cups (+MILK/−MILK), and sows were either crated or loose housed (CRATE/LOOSE) in a 2 × 2 × 2 factorial design. Piglet mortality was higher in LS17 compared to LS14 (P < 0.01; OR = 2.0), higher in −MILK compared to +MILK (P = 0.01; OR = 1.2) and higher in LOOSE compared to CRATE (P = 0.02; OR = 1.8). This study showed that sow rearing of supernumerary piglets while supplying with milk replacer can increase piglet survival. It also showed that early mortality before piglets learned to drink milk replacer posed a challenge using this automatic milk replacer system. An interaction between access to milk replacer and the standardised litter size D1 affected litter weight (P < 0.01) and piglet weight day 28 (D28) (P = 0.03). The highest litter weight D28 was found in LS17 +MILK (P < 0.01) but with a lower individual piglet weight than in LS14 −MILK. Piglet weight D28 was higher in LS14 −MILK compared to LS17 regardless of access to milk replacer. Heterogeneity in piglet weight within litters D28 was larger in LS17 (P = 0.03) but could be reduced with +MILK in CRATE (P < 0.01). No effects were found on sow weight loss and feed intake (P > 0.05). In conclusion, the results showed that sows cannot rear the supernumerary piglets without further management interventions to reduce mortality. Supplying supernumerary piglets equal to the mean live-born litter size of hyper-prolific sows with milk replacer can from results of this study be an alternative strategy to the use of nurse sows.     

Effect of changes in diet energy density on feed intake, milk yield and metabolic parameters in dairy cows in early lactation

The purpose of this experiment was to investigate how early lactating cows adjust their metabolism and production to acute, but moderate changes in the energy density of the diet. Sixty dairy cows were randomly assigned to one of four treatments: two change-over groups (HNH and NHN) and two control groups (HHH and NNN), where H and N refer to a high and normal energy density in the total mixed ration (TMR), respectively. The experimental period covered the first 9 weeks post calving, which was split up in three 3-week periods. Thus, cows assigned to HNH or NHN shifted TMR in weeks 4 and 7 after calving while cows assigned to HHH or NNN were fed the same TMR for all 9 weeks. Results from cows on treatment HNH were compared with group HHH while cows on treatment NHN were compared with group NNN. When the diet changed from N to H and H to N, cows increased and decreased their dry-matter intake (DMI), respectively compared with control groups. Cows adjusted milk yield accordingly to changes in DMI, although not always significantly. Energy-corrected milk yield was not significantly affected by any of the changes in the energy density of the diet but generally showed same tendencies as milk yield. Non-esterified fatty acids (NEFA), beta-hydroxybutyrate in blood and milk and triacylglycerol and glycogen content in the liver were not significantly affected by changes in the energy density of the diet, except from NEFA at one change. Glucose increased more when the diet changed from N to H and increased less when the diet changed from H to N, compared with control groups, although not always significantly. Collectively, these results suggest that cows adjust their DMI and partly milk yield according to the energy density of the diet and therefore only limited effects were observed in physiological parameters.     

Effects of konjac flour inclusion in gestation diets on the nutrient digestibility,lactation feed intake and reproductive performance of sows

This study was conducted to investigate the effects of konjac flour (KF) inclusion in gestation diets of sows on nutrients digestibility, lactation feed intake, reproductive performance of sows and preweaning performance of piglets. Two isoenergetic and isonitrogenous gestation diets were formulated: a control diet and a 2.1% KF-supplemented diet (KF diet). Both diets had the same NDF and insoluble fiber (ISF) levels, but the KF diet had higher soluble fiber (SF) level. The day after breeding, 96 multiparous sows were assigned to the two dietary treatments. Restrict-fed during gestation, in contrast, all sows were offered the same lactation diet ad libitum. Response criteria included sow BW, backfat depth, lactation feed intake, weaning-to-estrus interval, litter size and piglet’s weight at parturition and day 21 of lactation. On day 60 of gestation, 20 sows were used to measure nutrient digestibility. Results showed that the digestibility of dry matter, gross energy, crude fiber and ADF were not affected by the dietary treatments. The inclusion of KF in gestation diets increased NDF digestibility (P<0.05) and tended to increase the digestibility of CP (P=0.05) compared with the control diet group. In addition, dietary treatment during gestation did not affect litter size, BW and backfat gain during gestation, lactation weight, backfat loss or weaning-to-estrus interval of sows. However, sows fed the KF diet consumed more (P<0.05) lactation diet per day than sows in the control group. Accordingly, sows fed the KF diet showed greater average piglet weights on day 21 of lactation (P=0.09), and the litter weight of sows fed the KF diet on day 21 of lactation increased by 3.95 kg compared with sows fed the control diet (not significant). In conclusion, the inclusion of KF in gestation diets increased lactation feed intake of sows and tended to improve litter performance.     

Effect of lysophospholipids in diets differing in fat contents on growth performance,nutrient digestibility,milk composition and litter performance of lactating sows

It is well known that energy plays an important role in sow growth and development. Increasing the utilization of lipids will be beneficial to sows. Emulsifiers are substances which stabilize mixtures and prevent oil and water from separating, thereby enhancing the digestion of lipids. This study was conducted to evaluate the effect of dietary emulsifier (lysophospholipids (LPL)) supplementation in diets differing in fat contents on growth performance, nutrient digestibility and milk composition in lactating sows, as well as performance and fecal score in piglets. A total of 32 multiparous sows (Landrace×Yorkshire) were used in a 21-day experiment. On day 110 of gestation, sows were weighed and moved into the farrowing facility, randomly assigned in a 2×2 factorial arrangement according to their BW with two levels of LPL (0 and 30 mg/kg) and two levels of fat (4.75% and 2.38% fat; 13.66 and 13.24 MJ/kg). BW loss and backfat thickness loss were decreased (P<0.05) by LPL supplementation. Backfat thickness at weaning was higher (P<0.05) in sows fed LPL supplementation diets. The apparent total tract digestibility of dry matter, nitrogen, gross energy and crude fat in sows fed LPL diets was increased (P<0.05) compared with those fed non-LPL diets. Sows fed the high-fat diets had higher (P<0.05) milk fat on day 10 and milk lactose on day 20 than those fed the low-fat diets. Milk fat and lactose concentrations in LPL supplementation treatments was increased (P<0.05) compared with non-LPL treatments on day 10 and day 20, respectively. Positive interaction effects (P<0.05) between fat and LPL were observed for milk fat concentration on day 10. In conclusion, LPL addition decreased BW loss and backfat thickness loss, improved nutrient digestibility and milk fat as well as milk lactose concentrations. In addition, there was a complementary positive effect of dietary fat and LPL supplementation on milk fat concentration in lactating sows.     

The effect of varying duration of water restriction on drinking behaviour,welfare and production of lactating sows

Access to drinking water is essential for animal welfare, but it is unclear if temporary water restriction during the night represents a welfare problem. The aim of the present study was to investigate the effect of various durations of nightly restriction of water on thirst in loose housed lactating sows from day 10 to 28 of lactation. A total of 48 sows were deprived of water for either 0 h (n=12; control), 3 h (n=12; 0500 to 0800 h), 6 h (n=12; 0200 to 0800 h) or 12 h (n=12; 2000 to 0800 h). Control sows consumed 22% of their water intake during the night (2000 to 0800 h), whereas water consumption during this time was reduced to 13%, 7% and 0% in sows restricted for 3, 6 and 12 h. With increased duration of nightly water restriction a reduced latency to drink (26.8, 18.0, 5.3 and 6.7 min for 0, 3, 6 and 12 h sows; P<0.001) and an increased water intake during the 1^st hour after water became accessible (2.1, 3.4, 4.7 and 5.6 l for 0, 3, 6 and 12 h sows; P<0.001) was seen. During the last 30 min before water became accessible more sows deprived of water investigated (0%, 50%, 75%,and 50% of 0, 3, 6 and 12 h sows; P<0.01) or forcefully manipulated (0%, 17%, 50% and 33% of 0, 3, 6 and 12 h sows; P<0.05) the water trough, suggesting frustration and a negative experience of thirst. When all signs of imminent water access were provided, but access was delayed by 25 min, a tendency for more of the sows deprived of water for 6 and 12 h to interact forcefully with the water trough was seen (22%, 18%, 42% and 67% of 0, 3, 6 and 12 h sows; P=0.09). Duration of water restriction did not affect water consumption on a 24-h basis, nursing behaviour or performance. In conclusion, behavioural indicators of thirst increased with increasing duration of nightly water restriction in lactating sows.     

Impact of fat source and dietary fibers on feed intake,plasma metabolites,litter gain and the yield and composition of milk in sows

Sow lactation diets often include fat sources without considering the impact on digestion, metabolism and performance. Fiber ingredients may reduce feed intake and are often completely excluded from lactation diets, although locally available ingredients may be cost-efficient alternatives to partly replace cereals in lactation diets. Thus, a standard lactation diet low in dietary fiber, and two high-fiber diets based on sugar beet pulp (SBP) or alfalfa meal (ALF) were formulated. The SBP diet was high in soluble non-starch polysaccharides (NSP), whereas ALF being high in insoluble NSP. Each diet was divided in three portions and combined with 3% soybean oil (SOYO), palm fatty acid distillate (PFAD), or glycerol trioctanoate (C8TG) as the dietary fat source. Equal amounts of metabolizable energy were fed to 36 second parity sows from day 105 of gestation and throughout lactation to study the impact on feed intake, plasma metabolites, milk production and litter performance. Backfat thickness and BW of sows were recorded on days 3, 17 and 28 of lactation; blood was sampled on days 3 and 17; milk samples were obtained on days 3, 10, 17 and 24 of lactation; and piglets were weighed on days 2, 7, 14, 21 and 28 of lactation. Litter gain and milk yield during late lactation were greater in sows fed C8TG or SOYO than in sows fed PFAD (P=0.05), whereas loss of BW (P=0.60) and backfat (P=0.70) was unaffected by fat source. Milk protein on days 3 and 10 of lactation were lower in C8TG and SOYO sows, than in PFAD sows (P<0.05). The lowest concentration of plasma lactate on day 3 (P<0.05) and plasma acetate on day 17 (P<0.05) was observed in C8TG sows. Milk yield was unaffected by fiber treatment (P=0.43), whereas milk protein concentration was lowest in ALF sows (P<0.05). Feed intake tended to be lower (P=0.09), and litter gain during the 3^rd week of lactation was decreased (P<0.05) in SBP sows. In conclusion, performance was enhanced in SOYO and C8TG compared with PFAD sows, possibly associated with reduced energy intake in PFAD-fed sows. Furthermore, the SBP diet seemed to impair feed intake and litter gain at peak lactation, suggesting that effects of the dietary fiber fraction on energy intake determines the potential inclusion level of fiber-rich ingredients.     

Effects of feeding propylene glycol on dry matter intake, lactation performance, energy balance and blood metabolites in early lactation dairy cows

The objectives of this study were to evaluate effects of feeding propylene glycol (PG) on feed intake, milk yield and milk composition, blood metabolites and energy balance in Holstein dairy cows from 1 to 63 days in milk. Thirty-two multiparous cows, blocked by lactation number, previous 305-day milk production and expected calving date, were arranged into four groups in a randomized block design. Treatments were: control, low PG, medium PG and high PG with 0, 150, 300 and 450 ml PG per cow per day, respectively. The supplement of food grade PG (0.998 g/g PG) was hand-mixed into the top one-third of the daily ration. Cows were fed ad libitum a total mixed ration consisting of forage and concentrate (50 : 50, dry matter basis). Feed intake, milk yield and milk components were not affected (P > 0.05) by PG supplementation. Overall, body weight (BW) loss tended (P < 0.08) to be linearly reduced, and energy status was linearly improved with increasing PG supplementation. Concentrations of glucose in plasma were higher for cows fed PG relative to control (55.6 v. 58.9 mg/dl) and linearly increased (P < 0.01) with increasing PG supplementation. Plasma concentrations of non-esterified fatty acids and beta-hydroxybutyrate were linearly increased, but urine acetoacetate concentration was quadratically changed with the highest for control diet and the lowest for 450 ml/day of PG. These results indicated that supplementation of PG in the early lactating cow diets had minimal effects on feed intake and milk production, but may potentially reduce contents of milk fat and milk protein. Supplementation of early lactating dairy cow diets with PG is beneficial in terms of improving energy status and reducing BW loss.     

Effect of niacin supplementation on digestibility,nitrogen utilisation and milk and blood variables in lactating dairy cows fed a diet with a negative rumen nitrogen balance

The aim of the present experiment was to determine if a niacin supplementation of 6 g/d to lactating dairy cow diets can compensate negative effects of a rumen nitrogen balance (RNB) deficit. A total of nine ruminally and duodenally fistulated lactating multiparous German Holstein cows were successively assigned to one of three diets consisting of 10 kg maize silage (dry matter [DM] basis) and7 kg DM concentrate: Diet RNB– (n = 6) with energy and utilisable crude protein at the duodenum (uCP) according to the average requirement of the animals but with a negative RNB (–0.41 g N/MJ metabolisable energy [ME]); Diet RNB0 (n = 7) with energy, uCP and a RNB (0.08 g N/MJ ME) according to the average requirement of the animals and, finally, Diet NA (n = 5), which was the same diet as RNB–, but supplemented with 6 g niacin/d. Samples of milk were taken on two consecutive days, blood samples were taken on one day pre- and post-feeding and faeces and urine were collected completely over five consecutive days. The negative RNB reduced milk and blood urea content and apparent total tract digestibility of DM, organic matter (OM) and neutral detergent fibre (NDF). Also N excretion with urine, the total N excreted with urine and faeces and the N balance were reduced when the RNB was negative. Supplementation of niacin elevated plasma glucose concentration after feeding and the N balance increased. Supplementing the diet with a negative RNB with niacin led to a more efficient use of dietary N thereby avoiding the negative effects of the negative RNB on the digestibility of DM, OM and NDF.     

Effect of experimentally induced thyrotoxicosis on oxidative energy metabolism in rat heart mitochondria

Treatment of rats with T₃ resulted in a significant decrease in body weight, while the heart weight increased. T₄ treatment had less marked effect on body weights but resulted in decreased heart weights. Serum T₄ levels decreased significantly with simultaneous increase of T₃ level following T₃ treatment, whereas with T₄ treatment, levels of both T₄ and T₃ increased in the serum. Low doses of T₃ (0.5 μg ) caused decrease in mitochondrial protein content while high dose of T₄ (1 μg), caused significant increase in mitochondrial mass. The state 3 respiration rates were significantly depressed following T₃ and T₄ treatments, in a substrate specific manner with the effects being more pronounced with T₃; these responses with T₄ were dose-dependent for succinate and ascorbate + N,N,N′,N′-tetramethyl-p-phenylenedíamme. State 4 respiration rates also exhibited similar corresponding changes. ADP/O ratios were not changed but ADP-phosphorylation rates were decreased significantly particularly so with the T₃-treated animals. Treatment with T₃ also resulted in lowering of intramitochondrial cytochrome contents. Similar effects were seen also with higher doses of T₄. The results thus indicate that T_3- and T_4- thyrotoxicosis results in impaired energy metabolism in heart mitochondria.     

Effects of glyphosate residues and different concentrate feed proportions on performance,energy metabolism and health characteristics in lactating dairy cows

The aim of this study was to examine the influence of glyphosate (GL) residues in feedstuffs on performance, energy balance and health-related characteristics of lactating dairy cows fed diets with different concentrate feed proportions. After an adaption period, 64 German Holstein cows (207 ± 49 d in milk; mean ± SD) were assigned to either groups receiving a GL contaminated total mixed ration (TMR) (GL groups) or an uncontaminated TMR (CON groups) during a 16 weeks trial. Contaminated feedstuffs used were legally GL-treated peas and wheat (straw and grain). GL and CON groups were subdivided into a “low concentrate” group (LC) fed on dry matter (DM) basis of 21% maize silage, 42% grass silage, 7% straw and 30% concentrate and a “high concentrate” group (HC) composed of 11% maize silage, 22% grass silage, 7% straw and 60% concentrate for ad libitum consumption. Body condition score, body weight, DM intake and milk performance parameters were recorded. In blood serum, β-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA) and glucose were measured and energy balance was calculated. Milk was analysed for GL residues. At week 0, 7 and 15, general health status was evaluated by a modified clinical score. The average individual GL intake amounted for Groups CON_LC, CON_HC, GL_LC and GL_HC to 0.8, 0.8, 73.8 and 84.5 mg/d, respectively. No GL residues were detected in milk. GL contamination did not affect body condition score, body weight, DM intake, nutrient digestibility, net energy intake, net energy balance or BHB, glucose, NEFA and milk performance parameters; whereas concentrate feed proportion and time did affect most parameters. The clinical examination showed no adverse effect of GL-contaminated feedstuffs on cows’ health condition. In the present study, GL-contaminated feedstuffs showed no influence on performance and energy balance of lactating dairy cows, irrespective of feed concentrate proportion.     

Effects of dry period length on milk production and energy balance in two cow breeds

Shortening the dry period (DP) has been proposed as a strategy to improve energy balance (EB) in cows in early lactation. This study evaluated the effects of shortening the DP on milk yield (MY), EB and residual feed intake (RFI) in two breeds; Swedish Red (SR) and Swedish Holstein (SH). Cows were blocked by breed and parity and then randomly assigned to one of two treatments; short DP of 4 weeks (4W, n=43) or conventional DP of 8 weeks (8W, n=34). Cows were kept and fed under the same conditions, except for the 4 weeks when the 4W group were still lactating prepartum and thus kept with the lactating cows. Milk yield and BW were recorded and body condition score (BCS) was rated from 10 weeks prepartum to 12 weeks postpartum. Dry matter intake (DMI) was recorded for lactating cows postpartum. Milk yield was reduced by 6.75 kg/day during the first 12 weeks postpartum (P<0.001) for the 4W cows compared with 8W cows, but there was no significant difference in total MY (3724 kg compared with 3684 kg, P=0.7) when the milk produced prepartum was included. Protein content was higher in 4W cows (3.42%) than in 8W cows (3.27%) (P<0.001) postpartum. In the 8W group, cows lost more BCS after calving (P<0.05). Cows of SR breed had higher BCS than cows of SH breed (SR=3.7, SH=3.2, P<0.001), but no differences in BW were found between breed and treatment. Energy balance was improved for cows in the 4W group (P<0.001), while feed efficiency, expressed as RFI, was reduced for 4W cows than for 8W cows (5.91 compared with −5.39, P<0.01). Shortening the DP resulted in improved EB postpartum with no difference between the breeds and no milk losses when including the milk produced prepartum.     

低氧对脂肪细胞发育及脂质代谢调控研究进展

脂肪细胞的生长、分化与增殖贯穿整个生命过程,脂肪细胞中脂质代谢紊乱影响脂肪组织免疫和全身能量代谢。脂质代谢参与调控机体多种疾病的发生与发展,如高脂血症、非酒精性脂肪肝病、糖尿病和癌症等,对人和动物健康具有重大威胁。低氧诱导因子（hypoxia inducible factor,HIF）是介导机体组织器官中氧感受器的主要转录因子,HIF可调控脂质合成、脂肪酸代谢和脂滴形成并诱导疾病发生。但由于低氧程度、时间和作用方式的不同,对机体脂肪细胞发育和脂质代谢产生有害或有益的影响还无从定论。本文总结了低氧介导转录因子的调控作用以及对脂肪细胞发育和脂质代谢调控的研究进展,旨在揭示低氧诱导脂肪细胞代谢途径变化的潜在机制。     

Effect of dietary energy source on energy balance, production, metabolic disorders and reproduction in lactating dairy cattle

The pathway for oxidation of energy involves a balanced oxidation of C2 and C3 compounds. During early lactation in dairy cattle this C2/C3 ratio is out of balance, due to a high availability of lipogenic (C2) products and a low availability of glycogenic (C3) products relative of the C2 and C3 products required for milk production. This review compares studies which manipulated dietary energy source and shows that dietary energy source can affect the balance of the C2/C3 ratio, as indicated by plasma NEFA, beta-hydroxybutyrate (BHBA) and glucose levels. It is shown that glycogenic nutrients increase glucose and insulin concentrations and decrease NEFA and BHBA plasma levels. Extra lipogenic nutrients elevate NEFA and BHBA and decrease plasma glucose concentrations. Lipogenic nutrients generally increase milk fat percentage and decrease milk protein percentage, suggesting a surplus of C2 compounds. The inverse is the case for feeding extra glycogenic nutrients, implying reduced deamination and oxidation of glycogenic amino acids. Feeding extra glycogenic nutrients improved the energy balance (EB), in contrast to ambiguous results of lipogenic nutrients on EB. Moreover, glycogenic feed may reduce the severity of ketosis and fatty liver, but increased the incidence of (sub)clinical acidosis. Since studies are scarce, it seems difficult to draw conclusions on the effects of dietary energy source on reproduction. However, lipogenic nutrients decrease glucose and increase NEFA and BHBA plasma levels. High plasma NEFA and BHBA and low plasma glucose levels are associated with decreased reproductive performance, which might imply the C2/C3 compound balance to be important for reproductive function.     

Central and peripheral effects of ghrelin on energy balance, food intake and lipid metabolism in teleost fish

Ghrelin was first identified and characterized from rat stomach as an endogenous ligand for the growth hormone secretagogue receptor. Ghrelin and its receptor system are present not only in peripheral tissues such as stomach and intestine, but also in the central nervous system of mammals. Interestingly, administration of ghrelin induces an orexigenic effect and also modifies locomotor activity, suggesting its involvement in feeding control and the regulation of energy balance, in addition to the regulation of growth hormone release. Information about ghrelin in non-mammals, such as teleost fish, has also been increasing, and important data have been obtained. An understanding of the evolutionary background of the energy regulation system and the central and peripheral roles of ghrelin in teleost fish could provide indications as to their roles in mammals, particularly humans. In this review, we overview the central and peripheral effects of ghrelin on energy balance, locomotor activity, and lipid metabolism in teleost fish.     

High serum free fatty acids and low leptin levels: Plausible metabolic indicators of negative energy balance in early lactating Murrah buffaloes

Lactation is a highly demanding event in mammals, including buffaloes. It modulates the partitioning of nutrients, energy utilization, and food intake of the mother to meet her own and infant's energy needs. Failure to satisfy these energy needs leads to Negative Energy Balance (NEB). Currently, the only available indirect NEB indicator is Body Condition Score (BCS). However, direct dependency of the BCS on the peak depletion of body fat causes its inefficient use in a dairy farm. Thus, to establish objective NEB indicators in buffaloes, the serum levels of biochemical (serum β-hydroxybutyrate [BHBA] and free fatty acids [FFAs]), and endocrine (Growth Hormone [GH], insulin-like growth factor1 [IGF1], Insulin, and leptin) parameters were estimated in buffaloes. Our results revealed that serum FFA levels were significantly (p < 0.05) higher in high milk yielders (HMY) than low milk yielders (LMY) and heifers (H) during the 3rd and the 4th weeks of postpartum. The serum FFA levels were also significantly (p < 0.001) higher in the postpartum buffaloes with BCS < 3 in the field conditions. Further, serum leptin levels were significantly (p < 0.05) lower in HMY than LMY during the 3rd week of postpartum. However, the BHBA, GH, IGF1, and insulin levels were not significantly different between lactating buffaloes and H. These observations indicated that the NEB condition is probably restricted to the first month of early lactation in buffaloes. In conclusion, the simultaneous higher FFA and lower leptin levels could act as direct plausible metabolic indicators of NEB in buffaloes.     

Effects of iloprost,a PGI2 derivative,on ischemic myocardial energy and carbohydrate metabolism in dogs

Effects of iloprost, which is a stable prostacyclin analogue, on the ischemic myocardium were examined in the open-chest dog heart, in terms of biochemical parameters. Ischemia was initiated by ligating the left anterior descending coronary artery. When the coronary artery was ligated for 3 min, the levels or glycogen, fructose-1,6-diphosphate (FDP), adenosine triphosphate and creatinephosphate decreased, and the levels of glucose-6-phosphate (G6P), fructose-6-phosphate (F6P), lactate, adenosine diphosphate and adenosine monophosphate increased. During ischemia, therefore, energy charge potential was significantly decreased from 0.89±0.01 to 0.82±0.01, and ([G6P]+[F6P])/[FDP] and [lactate]/[pyruvate] ratios were significantly increased from 1.75±0.30 to 29.05±5.70 and 13±3 to 393±112, respectively. Iloprost (0.1, 0.3, or 1 g·kg^–1) was injected intravenously 5 min before the onset of ischemia. Iloprost (0.1, 0.3, and 1 g·kg^–1) reduced the ischemia-induced decrease in energy charge potential to 94, 74, and 86%, respectively, the increase in ([G6P]+[F6P]/[FDP] to 38, 29, 32%, respectively, and the increase in [lactate]/[pyruvate] to 67, 45, 65%, respectively. These results suggest that iloprost lessens the myocardial metabolic derangements produced by ischemia, and the most potent effect was obtained at the dose of 0.3 g·kg^–1.     

Effect of enteral nutritional products differing in carbohydrate and fat on indices of carbohydrate and lipid metabolism in patients with NIDDM

Non-insulin dependent diabetes mellitus (NIDDM) is associated with chronic hyperglycemia, which increases the risk of developing microvascular and macrovascular complications. Elevated triglyceride (TG) and VLDL cholesterol levels and low levels of HDL cholesterol have also been frequently reported in NIDDM patients. A diet high in complex carbohydrate and low in fat is typically recommended for management of NIDDM, however, this has recently been challenged by scientific reports of the benefits of dietary intakes high in monounsaturated fat. Thirty-two individuals with NIDDM were randomized to receive either Ensure with Fibre® (30% fat) or a high monounsaturated fatty acid product, Glucerna® (50% fat). These products were consumed for 28 days at 280% of daily energy intake. Post-treatment, dietary compliance was verified by a higher plasma TG 18:1 n-9 (p < 0.001) in the Glucerna® group and a higher plasma TG 18:2 n-6 (p < 0.001) in the Ensure with Fibre® group. The postprandial rise in blood glucose levels, determined by fingerprick samples, was significantly lower (p < 0.01) in the Glucerna® group. Trends of clinical interest were greater mean decreases in the Glucerna® group compared to the Ensure with Fibre® group in: fructosamine, 9.13 umol/L vs 0.14 umol/L; glucose, 1.61 mmol/L vs 0.63 mmol/L; and insulin, 46.0 pmol/L vs 12.6 pmol/L; respectively. However, overall, fasting plasma glucose, fructosamine, TG and cholesterol levels were not significantly different between groups. Thus, in these patients, the high monounsaturated fat diet and the standard diet were similar with regard to usual indicators of carbohydrate and lipid metabolism. A high monounsaturated fat diet appears to pose no risk to lipoprotein metabolism in NIDDM patients.