The present study investigated the potential role of the composition of dietary fatty acids in the regulation of biological rhythms, such as the sleep architecture, core body temperature and leukocyte clock gene expression, in subjects fed meals rich in palmitic acid (PA) or oleic acid (OA). Eleven males participated in two sessions of indirect calorimetry in a whole-room metabolic chamber. In each session, subjects consumed three meals rich in PA (44·3 % of total fat as PA and 42·3 % as OA) or OA (11·7 % of total fat as PA and 59·3 % as OA) in the metabolic chamber. The ratio of PA to OA in plasma was significantly lower and fat oxidation was significantly higher during 24 h of indirect calorimetry in the session with meals rich in OA than in that with meals rich in PA. The duration of slow wave sleep (SWS) was shorter, the latency of SWS was longer and the nadir of core body temperature after bedtime was later in the session with meals rich in PA than in that with meals rich in OA. The peak in CRY1 gene expression was earlier and its amplitude was higher in the session with meals rich in PA than in that with meals rich in OA. In healthy young males, meals rich in PA decreased fat oxidation and disrupted biological rhythms, particularly the sleep architecture and core body temperature during sleep, more than meals rich in OA.

Microplastics (MPs) pollution has been a hot research topic in recent years. MPs are ubiquitous throughout the ecological environment and are eventually accumulated in organisms through inhalation or ingestion. However, given that MPs are inert pollutants, their effects on organisms are not clear. In previous study, we have investigated the effects of polyethylene terephthalate MPs on physiology of Drosophila. What is the effect of polypropylene microplastics (PP-MPs)? The results of our experiments show that being exposed to high concentration of PP-MPs have significant effect on Drosophila. PP-MPs exposure can significantly increase locomotor activity and shorten the time of group sleep in Drosophila. In the presence of high concentrations of PP-MPs, the triglyceride content was reduced in females and their ability of egg production was affected. However, there was no significant effect on the level of protein and carbohydrate, or on the food intake. Our experimental results can provide some preliminary data for assessing the potential hazard of PP-MPs to other organisms.

The maintenance of a healthy mitochondrial network and the ability to adjust organelle population in response to internal or external stimuli are essential for the function and the survival of eukaryotic cells. Over the last two decades several studies have demonstrated the paramount importance of mitophagy, a selective form of autophagy that removes damaged and/or superfluous organelles, in organismal physiology. Post-mitotic neuronal cells are particularly vulnerable to mitochondrial damage, and mitophagy impairment has emerged as a causative factor in multiple neurodegenerative pathologies, including Alzheimer's disease and Parkinson's disease among others. Although mitochondrial turnover is a multifaceted process, neurons have to tackle additional complications, arising from their pronounced bioenergetic demands and their unique architecture and cellular polarisation that render the degradation of distal organelles challenging. Mounting evidence indicates that despite the functional conservation of mitophagy pathways, the unique features of neuronal physiology have led to the adaptation of compartmentalised solutions, which serve to ensure seamless mitochondrial removal in every part of the cell. In this review, we summarise the current knowledge concerning the molecular mechanisms that mediate mitophagy compartmentalisation and discuss their implications in various human pathologies.

In growing pigs, reduced growth during heat stress (HS) is mainly related to decreased feed intake. The study aimed to determine whether the reported positive effects of live yeast (LY) supplementation in HS pigs were due to a modified feeding behaviour or energy metabolism, and if these can be replicated by imposing an increased meal frequency. The effect of LY supplementation (0 (NS) v. 100 (LY) g/ton of feed), and of feeding window (FW) (unlimited or Unli, 2FW of 1 h each and 8FW of 15 min each) were measured in entire male finishing pigs (n 36). Ambient temperature was at 22°C during the thermoneutral (TN) period (5 d) and at 28°C during the HS period (5 d). Heat exposure decreased DM intake (DMI) and retained energy (RE) (–627 and −460 kJ·kg BW–0·60 · d–1, respectively; P < 0·01). During HS, LY supplementation in Unli pigs decreased inter-meal intervals (P = 0·02) attenuating HS effect on DMI which tended to improve RE (P = 0·09). NS – 8FW had higher DMI and RE than NS – 2FW (P < 0·05) but protein deposition (PD) were similar. Supplemented pigs had higher PD during HS regardless of FW (+18 g · d–1; P = 0·03). Comparing the 2FW groups, improved heat tolerance of LY-supplemented pigs were due to improved insulin sensitivity (P < 0·05) and latent heat loss capacity after a meal (P < 0·05) allowing them to increase their DMI (via an increased number of meals) and thus their energy efficiency. Imposing an increased meal frequency improved DMI in HS pigs but did not replicate positive effects of LY on PD.

Requirements for energy and particular amino acids (AAs) are known to be influenced by the extent of immune system stimulation. Most studies on this topic use models for immune system stimulation mimicking clinical conditions. Extrapolation to conditions of chronic, low-grade immune system stimulation is difficult. We aimed to quantify differences in maintenance energy requirements and efficiency of energy and protein used for growth (incremental energy and protein efficiency) of pigs kept under low (LSC) or high sanitary conditions (HSC) that were fed either a basal diet or a diet with supplemented AA. Twenty-four groups of six 10-week-old female pigs were kept under either LSC or HSC conditions for 2 weeks and fed a diet supplemented or not with 20% extra methionine, threonine and tryptophan. In week 1, feed was available ad libitum. In week 2, feed supply was restricted to 70% of the realized feed intake (kJ/(kg BW)0.6 per day) in week 1. After week 2, fasting heat production (FHP) was measured. Energy balances and incremental energy and protein efficiencies were measured and analyzed using a GLM. Low sanitary condition increased FHP of pigs by 55 kJ/(kg BW)0.6 per day, regardless of diet. Low sanitary condition did not alter the response of faecal energy output to incremental gross energy (GE) intake, but it reduced the incremental response of metabolizable energy intake (12% units), heat production (6% units) and energy retained as protein (6% units) to GE intake, leaving energy retained as fat unaltered. Incremental protein efficiency was reduced in LSC pigs by 20% units. Incremental efficiencies for energy and protein were not affected by dietary AA supplementation. Chronic, low-grade immune stimulation by LSC treatment increases FHP in pigs. Under such conditions, the incremental efficiency of nitrogen utilization for body protein deposition is reduced, but the incremental efficiency of absorbed energy for energy or fat deposition is unaffected.

Less invasive protocols are necessary to study energy expenditure (EE) of cats living in homes for expressing their normal living conditions. The present study compared sampling times and the use of saliva, urine and blood to measure 2H and 18O to apply the doubly labelled water method. In the first study, four cats were used to evaluate the enrichment (2, 4, 6, 7 and 8 h) and elimination (2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 d) of 2H and 18O (subcutaneously injected). The maximum enrichment was after 5 h (R2 0·82) of injection, with an Ln linear elimination of both isotopes (P < 0·001; R2 0·99). The results of EE were similar, regardless of the sampling time used (P = 0·999). In the second study, seven male cats and seven female cats were used. Before and after isotope injection (5 h, 7 d, 10 d and 14 d), blood, saliva and urine were collected. Isotope enrichment was lower in urine (P < 0·05) and at the similar level in blood and saliva. Isotope elimination was similar for all fluids (P < 0·473). The EE calculated with blood and saliva was similar but higher for urine (P = 0·015). According to Bland–Altman statistics, blood and saliva presented low bias and high correlation (P < 0·001), but this was not observed for urine (P = 0·096). Higher EE was observed for male cats (384 (se 39) kJ/kg0·67 per d) than for female cats (337 (se 34) kJ/kg0·67 per d; P < 0·05). The sampling time for the method is flexible, and saliva can be used as a substitute for blood.

Misalignment of day/night and feeding rhythms has been shown to increase fat deposition and the risk for metabolic disorders in humans and rodents. In most studies, however, food intake and intake patterns are not controlled. We studied the effects of circadian misalignment on energy expenditure in pigs while controlling for food intake as well as intake patterns. Twelve groups of five male pigs were housed in respiration chambers and fed either during the day (10.00–18.00 hours; DF) or night (22.00–06.00 hours; NF), bihourly the same sequential meals, representing 15, 10, 25, 30 and 20 % of the daily allowance. Paired feeding was applied to ensure equal gross energy intake between treatments. Apparent total tract digestibility, energy balances and heat partitioning were measured and analysed using a mixed linear model. Apparent total tract energy and DM digestibility tended to be lower for NF-pigs than DF-pigs (P < 0·10). Heat production was 3 % lower for NF-pigs than DF-pigs (P < 0·026), increasing fat retention by 7 % in NF-pigs (P = 0·050). NF-pigs were less active than DF-pigs during the feeding period, but more active during the fasting period. RMR was greater for DF-pigs than NF-pigs during the fasting period. Methane production was 30 % greater in NF-pigs than DF-pigs (P < 0·001). In conclusion, circadian misalignment has little effect on nutrient digestion, but alters nutrient partitioning, ultimately increasing fat deposition. The causality of the association between circadian misalignment and methane production rates remains to be investigated.

Oxidative stress occurs when oxidant production exceeds the antioxidant capacity to detoxify the reactive intermediates or to repair the resulting damage. Feed efficiency has been associated with mitochondrial function due to its impact on cell energy metabolism. However, mitochondria are also recognized as a major source of oxidants. The aim of this study was to determine lipid and protein oxidative stress markers, and gene and protein expression as well as activity of antioxidant enzymes in the liver of steers of divergent residual feed intake (RFI) phenotypes. Hereford steers (n = 111) were evaluated in post-weaning 70 days standard test for RFI. Eighteen steers exhibiting the greatest (n = 9; high-RFI) and the lowest (n = 9; low-RFI) RFI values were selected for this study. After the test, steers were managed together under grazing conditions until slaughter when they reached the slaughter body weight. At slaughter, hepatic samples were obtained, were snap-frozen in liquid nitrogen and stored at −80°C until analyses. Hepatic thiobarbituric acid reactive species and protein carbonyls were greater (P = 0.05) and hepatic 4-hydroxynonenal protein adducts tended (P = 0.10) to be greater for high- than low-RFI steers. Hepatic gene expression glutathione peroxidase 4, glutamate–cysteine ligase catalytic subunit and peroxiredoxin 5 mRNA was greater (P ≤ 0.05) and glutathione peroxidase 3 mRNA tended (P = 0.10) to be greater in low- than high-RFI steers. Hepatic protein expression and enzyme activity of manganese superoxide dismutase and glutathione peroxidase enzyme activity tended (P ≤ 0.10) to be greater for low- than high-RFI steers. High-efficiency steers (low-RFI) probably had better hepatic oxidative status which was strongly associated with greater antioxidant ability near to the oxidant production site and, therefore, reduced oxidative stress of the liver. Decreased hepatic oxidative stress would reduce maintenance requirements due to a lower protein and lipid turnover and better efficiency in the use of energy.

Currently, energy evaluation of fish feeds is performed on a digestible energy basis. In contrast to net energy (NE) evaluation systems, digestible energy evaluation systems do not differentiate between the different types of digested nutrients regarding their potential for growth. The aim was to develop an NE evaluation for fish by estimating the energy efficiency of digestible nutrients (protein, fat and carbohydrates) and to assess whether these efficiencies differed between Nile tilapia and rainbow trout. Two data sets were constructed. The tilapia and rainbow data set contained, respectively, eight and nine experiments in which the digestibility of protein, fat and energy and the complete energy balances for twenty-three and forty-five diets was measured. The digestible protein (dCP), digestible fat (dFat) and digestible carbohydrate intakes (dCarb) were calculated. By multiple regression analysis, retained energy (RE) was related to dCP, dFat and dCarb. In tilapia, all digestible nutrients were linearly related to RE (P<0·001). In trout, RE was quadratically related to dCarb (P<0·01) and linearly to dCP and dFat (P<0·001). The NE formula was NE=11·5×dCP+35·8×dFAT+11·3×dCarb for tilapia and NE=13·5×dCP+33·0×dFAT+34·0×dCarb–3·64×(dCarb)2 for trout (NE in kJ/(kg0·8×d); dCP, dFat and dCarb in g/(kg0·8×d)). In tilapia, the energetic efficiency of dCP, dFat and dCarb was 49, 91 and 66 %, respectively, showing large similarity with pigs. Tilapia and trout had similar energy efficiencies of dCP (49 v. 57 %) and dFat (91 v. 84 %), but differed regarding dCarb.

Leucine plays an important role in promoting muscle protein synthesis and muscle remodelling. However, what percentage of leucine is appropriate in creep feed and what proteome profile alterations are caused by dietary leucine in the skeletal muscle of piglets remain elusive. In this case, we applied isobaric tags for relative and absolute quantitation to analyse the proteome profile of the longissimus dorsi muscles of weanling piglets fed a normal leucine diet (NL; 1·66 % leucine) and a high-leucine diet (HL; 2·1 % leucine). We identified 157 differentially expressed proteins between these two groups. Bioinformatics analysis of these proteins exhibited the suppression of oxidative phosphorylation and fatty acid β-oxidation, as well as the activation of glycolysis, in the HL group. For further confirmation, we identified that SDHB, ATP5F1, ACADM and HADHB were significantly down-regulated (P<0·01, except ATP5F1, P<0·05), whereas the glycolytic enzyme pyruvate kinase was significantly up-regulated (P<0·05) in the HL group. We also show that enhanced muscle protein synthesis and the transition from slow-to-fast fibres are altered by leucine. Together, these results indicate that leucine may alter energy metabolism and promote slow-to-fast transitions in the skeletal muscle of weanling piglets.

Chlorogenic acids (CGA) are the most abundant polyphenols in coffee. Continuous consumption of CGA reduces body fat and body weight. Since energy metabolism and sleep are controlled by common regulatory factors, consumption of CGA might modulate sleep. Lack of sleep has been identified as a risk factor for obesity, hypertension and type 2 diabetes. The aim of this study was to determine the effects of ingesting CGA over 5 d on energy metabolism and sleep quality in humans. A total of nine healthy subjects (four male and five female) completed a placebo-controlled, double-blinded, cross-over intervention study. Subjects consumed a test beverage containing 0 or 600 mg of CGA for 5 d. On the fifth night, subjects stayed in a whole-room metabolic chamber to measure energy metabolism; sleep was evaluated using polysomnographic recording. It was found that CGA shortened sleep latency (9 (sem 2) v. 16 (sem 4) min, P<0·05) compared with the control, whereas no effect on sleep architecture, such as slow-wave sleep, rapid eye movement or waking after sleep onset, was observed. Indirect calorimetry revealed that consumption of CGA increased fat oxidation (510 (sem 84) kJ/8 h (122 (sem 20) kcal/8 h) v. 331 (sem 79) kJ/8 h (81 (sem 19) kcal/8 h), P<0·05) but did not affect energy expenditure during sleep. Consumption of CGA enhanced parasympathetic activity assessed from heart-rate variability during sleep (999 (sem 77) v. 919 (sem 54), P<0·05). A period of 5-d CGA consumption significantly increased fat oxidation during sleep, suggesting that beverages containing CGA may be beneficial to reduce body fat and prevent obesity. Consumption of CGA shortened sleep latency and did not adversely affect sleep quality.

The present study investigated whether changes of energy metabolism post-partum (pp) are associated with claw health. For this purpose, back-fat-thickness (BFT) was measured and blood samples were taken from 146 cows at four examination times. The serum levels of free fatty acids (FFA), ß-hydroxybutyrate (BHB) and glucose were measured. Furthermore, in the first week postpartum (pp) and at 8 weeks pp, a claw trimming was done and the presence and extent of sole haemorrhages (SH) was recorded. Animals with high BFT at calving and therefore high fat mobilisation and whose FFA and BHB levels in the first week pp exceeded the reference values had fewer pathological changes of the claws than thinner animals whose FFA and BHB levels stayed within reference ranges. The body condition before calving, represented in this study by BFT, plays an important role in non-infectious claw disorders. Poorer body condition was found to be associated with the SH that develop in the first 2 months of lactation.

This study aimed to verify the effect of aerobic exercise performed in the fasted v. fed states on fat and carbohydrate metabolism in adults. Searches were conducted in March 2015, and updated in July 2016, using PubMed®, Scopus and Cochrane databases (terms: ‘fasting’, ‘exercise’, ‘aerobic exercise’, ‘substrate’, ‘energy metabolism’, ‘fat’, ‘glucose’, ‘insulin’ and ‘adult’) and references from selected studies. Trials that compared the metabolic effects of aerobic exercise (duration ≤120 min) performed in the fasted v. fed states in adults were accepted. The outcomes evaluated were fat oxidation during exercise and the plasma concentrations of insulin, glucose and NEFA before and immediately after exercise; two independent reviewers extracted the data (A. F. V. and L. C.). The results were presented as weighted mean differences between treatments, with 95 % CI. Of 10 405 articles identified, twenty-seven studies – with a total of 273 participants – were included. There was a significant increase in fat oxidation during exercise performed in the fasted, compared with fed, state (−3·08 g; 95 % CI −5·38, −0·79; I2 39·1 %). The weighted mean difference of NEFA concentrations was not significantly different between states (0·00 mmol/l; 95 % CI −0·07, 0·08; I2 72·7 %). However, the weighted mean differences of glucose (0·78 mmol/l; 95 % CI 0·43, 1·14; I2 90·8 %) and insulin concentrations (104·5 pmol/l; 95 % CI 70·8, 138·2; I2 94·5 %) were significantly higher for exercise performed in the fed state. We conclude that aerobic exercise performed in the fasted state induces higher fat oxidation than exercise performed in the fed state.

Metabolic adaptation includes an array of concerted metabolic and endocrine events that enable dairy cows bridging the period of energy deficit at the onset of lactation. The present study evaluated metabolic, endocrine and reticuloruminal pH changes in 30 (25 Holstein and five Simmental) periparturient dairy cows experiencing variable lipolysis early postpartum. Cows were fed the same close-up and fresh lactation diets and kept in the same management conditions. Blood samples were collected at day 14, and day 4, relative to expected parturition, and at day 2, and day 21 postpartum, and serum metabolites and hormones related to glucose and lipid metabolism, as well as concentrations of several liver enzymes and acute phase proteins were determined. Additionally, reticuloruminal pH was monitored every 10 min over the last 3 days of the observation period. BW and milk yields were recorded and balances of energy and protein were assessed. Based on serum concentration of non-esterified fatty acids (NEFA) postpartum, cows were retrospectively classified into low (n=8), medium (n=11), and high (n=11) lipolysis groups, with NEFA levels of <0.4 mmol/l, between 0.4 and 0.7 mmol/l, and >0.7 mmol/l, respectively. Overall, elevated NEFA concentrations in the High group went along with a higher ratio of NEFA to cholesterol and reduced insulin sensitivity. While serum glucose, energy deficit and BW loss did not differ, cows of the High group exhibited increased lactate concentrations in the serum, compared with the Medium group. No differences in liver enzymes and acute phase proteins were evidenced among fat mobilization groups, whereas concentration of serum billirubin was lowest in the Low group after parturition. Data of milk yield and milk energy output showed no differences among groups, despite divergences in calculated energy balance and BW change postpartum. Cows of the Low group tended to increase dry matter intake but also showed longer time duration of pH below 6.0 in the reticulorumen (on average 299 min/day compared with 99 and 91 min/day for Medium and High groups, respectively). Differences in metabolic, endocrine and reticuloruminal pH responses indicate diverse metabolic adaptation strategies of early-lactation cows to cope with energy deficit postpartum.

We previously reported that medium-chain TAG (MCT) could alleviate hepatic oxidative damage in weanling piglets with intra-uterine growth retardation (IUGR). There is a relationship between oxidative status and energy metabolism, a process involved in substrate availability and glucose flux. Therefore, the aim of this study was to investigate the effects of IUGR and MCT on hepatic energy metabolism and mitochondrial function in weanling piglets. Twenty-four IUGR piglets and twenty-four normal-birth-weight (NBW) piglets were fed a diet of either soyabean oil (SO) or MCT from 21 d of postnatal age to 49 d of postnatal age. Then, the piglets’ biochemical parameters and gene expressions related to energy metabolism and mitochondrial function were determined (n 4). Compared with NBW, IUGR decreased the ATP contents and succinate oxidation rates in the liver of piglets, and reduced hepatic mitochondrial citrate synthase (CS) activity (P<0·05). IUGR piglets exhibited reductions in hepatic mitochondrial DNA (mtDNA) contents and gene expressions related to mitochondrial biogenesis compared with NBW piglets (P<0·05). The MCT diet increased plasma ghrelin concentration and hepatic CS and succinate dehydrogenase activities, but decreased hepatic pyruvate kinase activity compared with the SO diet (P<0·05). The MCT-fed piglets showed improved mtDNA contents and PPARγ coactivator-1α expression in the liver (P<0·05). The MCT diet alleviated decreased mRNA abundance of the hepatic PPARα induced by IUGR (P<0·05). It can therefore be postulated that MCT may have beneficial effects in improving energy metabolism and mitochondrial function in weanling piglets.

Seventeen non-lactating dairy-bred suckler cows (LF; Limousin×Holstein-Friesian) and 17 non-lactating beef composite breed suckler cows (ST; Stabiliser) were used to study enteric methane emissions and energy and nitrogen (N) utilization from grass silage diets. Cows were housed in cubicle accommodation for 17 days, and then moved to individual tie-stalls for an 8-day digestibility balance including a 2-day adaption followed by immediate transfer to an indirect, open-circuit, respiration calorimeters for 3 days with gaseous exchange recorded over the last two of these days. Grass silage was offered ad libitum once daily at 0900 h throughout the study. There were no significant differences (P>0.05) between the genotypes for energy intakes, energy outputs or energy use efficiency, or for methane emission rates (methane emissions per unit of dry matter intake or energy intake), or for N metabolism characteristics (N intake or N output in faeces or urine). Accordingly, the data for both cow genotypes were pooled and used to develop relationships between inputs and outputs. Regression of energy retention against ME intake (r2=0.52; P<0.001) indicated values for net energy requirements for maintenance of 0.386, 0.392 and 0.375 MJ/kg0.75 for LF+ST, LF and ST respectively. Methane energy output was 0.066 of gross energy intake when the intercept was omitted from the linear equation (r2=0.59; P<0.001). There were positive linear relationships between N intake and N outputs in manure, and manure N accounted for 0.923 of the N intake. The present results provide approaches to predict maintenance energy requirement, methane emission and manure N output for suckler cows and further information is required to evaluate their application in a wide range of suckler production systems.

The overall goal of this study was to evaluate if intermediary energy metabolism of cows fed with trans-10, cis-12 conjugated linoleic acid (CLA) was modified such that milk-energy compounds were produced with less intermediary energy expenditure as compared to control cows. Published data on supplemented CLA were assembled. The extent was calculated to which the trans-10, cis-12 CLA isomer has an impact on glucose and energy conversion in the mammary gland by modifying glucose equivalent supply and energy required for fatty acid (FA) and fat synthesis, and if this will eventually lead to an improved glucose and energy status of CLA-supplemented high-yielding dairy cows. A possible relationship between CLA supplementation level and milk energy yield response was also studied. Calculations were conducted separately for orally and abomasally administered CLA and based on energy required for supply of glucose equivalents, i.e. lactose, glycerol and NADPH2. Further, modifications of milk FA profile due to CLA supplementation were considered when energy expenditures for FA and fat synthesis were quantified. Differences in yields between control and CLA groups were transformed into glucose energy equivalents. Only abomasal infusion (r2 = 0·31) but not oral CLA administration (r2 = 0·11) supplementation to dairy cow diets resulted in less glucose equivalent energy. Modifications of milk FA profiles also saved energy but the relationship with CLA supplementation was weaker for abomasal infusion (r2 = 0·06) than oral administration (r2 = 0·38). On average, 10 g/d of abomasally infused trans-10, cis-12 CLA saved 1·1 to 2·3 MJ net energy expressed as glucose equivalents, whereas both positive and negative values were observed when the trans-10, cis-12 CLA was fed to the cows.

This study revealed a weak to moderate dose-dependent relationship between the amount of trans-10, cis-12 CLA administered and the amount of energy in glucose equivalents and energy for the synthesis of milk fat conserved from milk ingredient synthesis. Because abomasal infusion of the trans-10, cis-12 CLA more consistently conserved energy in glucose equivalents compared with oral CLA intake, rumen protection of the fed CLA products appears incomplete. Milk fat synthesis showed an energy saving with a weak dose-dependent relationship when CLA was supplemented orally or by abomasal infusion.

The increasing use of unconventional feedstuffs in chicken’s diets results in the substitution of starch by lipids as the main dietary energy source. To evaluate the responses of genetically fat or lean chickens to these diets, males of two experimental lines divergently selected for abdominal fat content were fed isocaloric, isonitrogenous diets with either high lipid (80 g/kg), high fiber (64 g/kg) contents (HL), or low lipid (20 g/kg), low fiber (21 g/kg) contents (LL) from 22 to 63 days of age. The diet had no effect on growth performance and did not affect body composition evaluated at 63 days of age. Glycolytic and oxidative energy metabolisms in the liver and glycogen storage in liver and Sartorius muscle at 63 days of age were greater in chicken fed LL diet compared with chicken fed HL diet. In Pectoralis major (PM) muscle, energy metabolisms and glycogen content were not different between diets. There were no dietary-associated differences in lipid contents of the liver, muscles and abdominal fat. However, the percentages of saturated (SFA) and monounsaturated fatty acids (MUFA) in tissue lipids were generally higher, whereas percentages of polyunsaturated fatty acids (PUFA) were lower for diet LL than for diet HL. The fat line had a greater feed intake and average daily gain, but gain to feed ratio was lower in that line compared with the lean line. Fat chickens were heavier than lean chickens at 63 days of age. Their carcass fatness was higher and their muscle yield was lower than those of lean chickens. The oxidative enzyme activities in the liver were lower in the fat line than in the lean line, but line did not affect energy metabolism in muscles. The hepatic glycogen content was not different between lines, whereas glycogen content and glycolytic potential were higher in the PM muscle of fat chickens compared with lean chickens. Lipid contents in the liver, muscles and abdominal fat did not differ between lines, but fat chickens stored less MUFA and more PUFA in abdominal fat and muscles than lean chickens. Except for the fatty acid composition of liver and abdominal fat, no interaction between line and diet was observed. In conclusion, the amount of lipids stored in muscles and fatty tissues by lean or fat chickens did not depend on the dietary energy source.

Seed germination is regulated in a concerted manner that involves generating growth potential in the embryo to overcome the mechanical resistance of the endosperm. The wake-up call of a dry seed includes the reorganization of subcellular structures and the reactivation of metabolism in a dense, oxygen-poor environment. Pools of unbound metabolites and solutes produced by the degradation of storage reserves, including starch, proteins and oils, in the embryo can contribute to the generation of the embryo growth potential and radicle protrusion. Recent genomics studies have contributed a vast amount of data on protein, metabolite and gene transcript profiles during germination, which can be integrated to explore the seed metabolism from water imbibition to radicle protrusion. To what extent are free pools of metabolites relevant to the reorganization of seed metabolism? How is energy built to support embryo growth and radicle protrusion? Elucidating these fundamental questions in seed biology is the key to the understanding of the germination process. Here we have attempted to summarize the recent scientific knowledge to provide a comprehensive description of the ignition, reassembling and regulation of metabolism during seed germination.