Refeeding Phase Research Articles

Adaptive metabolic response to short-term intensive fasting

Short-term intensive fasting (STIF), known as beego in Chinese phonetic articulation, has been practiced for more than two thousand years. However, the potential risk of STIF and the body's response to the risk have not been adequately evaluated. This study aims to address this issue, focusing on the STIF-triggered metabolic response of the liver and kidney. The STIF procedure in the clinical trial includes a 7-day water-only intensive fasting phase and a 7-day gradual refeeding phase followed by a regular diet. The intensive fasting in humans was assisted with psychological induction. To gain insights not available in the clinical trial, we designed a STIF program for mice that resulted in similar phenotypes seen in humans. Plasma metabolic profiling and examination of gene expression as well as liver and kidney function were performed by omics, molecular, biochemical and flow cytometric analyses. A human cell line model was also used for mechanistic study. Clinically significant metabolites of fat and protein were found to accumulate during the fasting phase, but they were relieved after gradual refeeding. Metabolomics profiling revealed a universal pattern in the consumption of metabolic intermediates, in which pyruvate and succinate are the two key metabolites during STIF. In the STIF mouse model, the accumulation of metabolites was mostly counteracted by the upregulation of catabolic enzymes in the liver, which was validated in a human cell model. Kidney filtration function was partially affected by STIF but could be recovered by refeeding. STIF also reduced oxidative and inflammatory levels in the liver and kidney. Moreover, STIF improved lipid metabolism in mice with fatty liver without causing accumulation of metabolites after STIF. The accumulation of metabolites induced by STIF can be relieved by spontaneous upregulation of catabolic enzymes, suggesting an adaptive and protective metabolic response to STIF stress in the mammalian body.

Starvation hepatitis and refeeding-induced hepatitis: mechanism, diagnosis, and treatment.

Anorexia nervosa (AN) is one of the most common psychiatric disorders among young adults and is associated with a substantial risk of death from suicide and medical complications. Transaminase elevations are common in patients with AN at the time of hospital admission and have been associated with longer lengths of hospital stay. Multiple types of hepatitis may occur in these patients, including two types that occur only in patients with AN: starvation hepatitis and refeeding-induced hepatitis. Starvation hepatitis is characterized by severe transaminase elevation in patients in the advanced phase of protein-energy deprivation and is associated with complications of severe starvation, such as hypoglycaemia, hypothermia, and hypotension. Refeeding-induced hepatitis is characterized by a milder increase in transaminases that occurs in the early refeeding phase and is associated with hypophosphatemia, hypokalemia, and hypomagnesaemia. Among the most common forms of hepatitis, drug-induced liver injury is particularly relevant in this patient cohort, given the frequent use and abuse of methamphetamines, laxatives, antidepressants, and antipsychotics. In this review, we provided an overview of the different forms of anorexic-associated hepatitis, a diagnostic approach that can help the clinician to correctly frame the problem, and indications on their management and treatment.

Physiological responses associated with compensatory growth of Colossoma macropomum submitted to different feeding rates

Colossoma macropomum, popularly known as tambaqui, is the most commercially cultivated native species in South America. Our study aimed to evaluate a series of endpoints related to growth response and physiological parameters in C. macropomum juveniles submitted to different feeding rates (FR) and subsequent refeeding. Fish were fed at five different FR (2%, 4%, 6%, 8%, and 10% of body weight per day) for 30 days (restricted feeding phase) and then refed until apparent satiation for another 30 days (refeeding phase). Growth parameters increased with increasing FR. The FR for maximum growth was estimated to be 8.98% day −1. The reduction in FR negatively affected the activity of digestive enzymes, intestinal histomorphometry, proximal composition, plasma metabolites, and antioxidant capacity. However, after refeeding, these physiological variables were mostly restored. Our results indicate that a FR of 6% day−1 provided the best growth and feed conversion, while the full compensatory growth was achieved at 4% day−1 after refeeding. Collectively, our data suggest that a FR of 2% day−1 can trigger the catabolism of endogenous reserves, an impeding factor for compensatory growth.

Effect of Melatonin Implants and Nutritional Restriction on Growth Performance of Local Male Lambs.

This experiment was conducted from 17 October 2021 to 9 January 2022 on the Department of Animal Production sheep field at the College of Agriculture, University of Anbar. The study aimed to determine the impact of melatonin implants and dietary restrictions on local male lambs' nutritional and growth performance. It included 16 local male lambs ranging in age from 5 to 6 months and weighing an average of 35.31 3.71 kg. The lambs were separated into four equal groups (n=4) and placed in separate pens. The actual duration of the experiment was 69 days, divided into two phases: the first phase consisted of 42 days of nutritional restriction, and the second phase consisted of 27 days of re-nutrition. As a control treatment during the stage of nutritional restriction, the first group (T1) was fed ad libitum. In contrast, the second group (T2) was fed Ad libitum with 36 mg subcutaneous-ear implanted melatonin implants, and the third group (T3) was fed a restricted diet (R) of 75% of the Ad libitum. Comparatively, the fourth group (T4) was fed a restricted diet of 75% of the Ad libitum with 36 mg of subcutaneous-ear implanted Melatonin. Until the end of the re-feeding phase, all experimental treatments were provided with unrestricted access to food. The nutritional and growth performance parameters were measured during the nutritional restriction and re-feeding stage and the entire experiment duration. During the nutritional restriction stage (42 days), there was no significant difference between the experimental treatments in terms of total weight gain, daily weight gain, feed conversion efficiency, and feeding efficiency. However, the experimental groups exhibited statistically significant differences in daily feed intake, daily dry matter intake, and dry matter intake as a percentage of body weight. In the re-feeding stage, there were no significant differences in the above nutritional and growth parameters among the experimental groups (27 days). This experiment concluded that feeding local male lambs 75% of Ad libitum with or without melatonin implants for 42 days, followed by re-feeding for 27 days, maintained the growth performance of the lambs with minimal feed intake and reduced lamb production costs.

5:2 intermittent fasting tapers food intake in the refeeding state and ameliorates metabolic disturbances in mice exposed to olanzapine.

A considerable number of patients suffer from adverse metabolic reactions caused by atypical antipsychotics (AAPs), however, current management strategies are disappointing to clinicians. Preclinical studies have consistently demonstrated that intermittent fasting (IF) has robust disease-modifying efficacy in animal models in a wide range of pathological conditions, especially obesity and diabetes. However, it is unclear what role IF can play in addressing AAPs-induced metabolic disturbances. In our study, we found that a 5:2 IF regimen significantly ameliorated the metabolic disturbances induced by olanzapine (a drug representative of AAPs) in animal models. Meanwhile, our research suggests that IF altering food intake during the refeeding phase may account for the metabolic benefit. This study provides supporting evidence regarding a potentially cost-effective intervention strategy for AAPs-induced metabolic disturbances.

CTRP11 contributes modestly to systemic metabolism and energy balance.

C1q/TNF‐related proteins (CTRP1‐15) constitute a conserved group of secreted proteins of the C1q family with diverse functions. In vitro studies have shown that CTRP11/C1QL4 can inhibit adipogenesis, antagonize myoblast fusion, and promote testosterone synthesis and secretion. Whether CTRP11 is required for these processes in vivo remains unknown. Here, we show that knockout (KO) mice lacking CTRP11 have normal skeletal muscle mass and function, and testosterone level, suggesting that CTRP11 is dispensable for skeletal muscle development and testosterone production. We focused our analysis on whether this nutrient‐responsive secreted protein plays a role in controlling sugar and fat metabolism. At baseline when mice are fed a standard chow, CTRP11 deficiency affects metabolic parameters in a sexually dimorphic manner. Only Ctrp11‐KO female mice have significantly higher fasting serum ketones and reduced physical activity. In the refeeding phase following food withdrawal, Ctrp11‐KO female mice have reduced food intake and increased metabolic rate and energy expenditure, highlighting CTRP11’s role in fasting–refeeding response. When challenged with a high‐fat diet to induce obesity and metabolic dysfunction, CTRP11 deficiency modestly exacerbates obesity‐induced glucose intolerance, with more pronounced effects seen in Ctrp11‐KO male mice. Switching to a low‐fat diet after obesity induction results in greater fat loss in wild type relative to KO male mice, suggesting impaired response to obesity reversal and reduced metabolic flexibility in the absence of CTRP11. Collectively, our data provide genetic evidence for novel sex‐dependent metabolic regulation by CTRP11, but note the overall modest contribution of CTRP11 to systemic energy homeostasis.

Effects of a single-phase fasting period and subsequent re-feeding on compensatory growth, digestive enzyme activities, and antioxidant capacity of sobaity (Sparidentex hasta) and yellowfin seabream (Acanthopagrus latus)

Abstract An eight-week research was carried out to examine the influence of fasting (FA) and refeeding (RF) episodes on the compensatory growth responses (CGR) in sobaity (Sparidentex hasta, 10 g) and yellowfin seabreams (Acanthopagrus latus, 4.3 g) juveniles. Fish were fed with a commercial feed (contained 500 g kg−1 crude protein and 150 g kg−1 crude lipid) as following regimes: control (C, fish were fed three times every day), T1 (two weeks of feeding, one week of FA, and five weeks of RF), T2 (one week of feeding, two weeks of FA and five weeks of RF) and T3 (three weeks of FA and five weeks of RF). Two hundred and forty S. hasta juveniles were stocked into twelve 300-L tanks (20 fish tank−1), and 360 A. latus juveniles were allocated into other 12 tanks (30 fish tank−1). Each treatment was carried out in triplicates for each species, and each tank held only one of the species. The experiment was carried out for both species simultaneously. The weight and length of fish from the four groups were measured individually after the third week (after FA episode) and after eight weeks (after RF episode). After finishing the RF episode (eighth week), six fish of each tank were sacrificed with an overdose of 2-phenoxyethanol (1000 mg L–1), and the liver and the whole gut of the sacrificed fish were sampled, dissected, and then kept in a freezer (−80°C) until further analyses. Survival rate was decreased in S. hasta juveniles with increasing the FA period mainly due to their cannibalistic behavior, which was triggered by starvation, but it was not affected in A. latus. The fasted groups in both species significantly lost their weight after FA episodes. After five weeks of RF, S. hasta showed full compensatory growth response; meanwhile A. latus had a partial compensatory response (P<0.05). Hepatosomatic index value decreased after the FA period in both species, but it was restored to the normal level after RF phase. The activities of liver catalase, superoxide dismutase, glutathione-S-transferase, and glutathione peroxidase were increased in T2 group in S. hasta, but liver antioxidant enzymes were not affected in A. latus. In both species, the amount of the lipid peroxidation was significantly increased in the liver of fish groups subjected to T2 or T3 compared to T1 and control groups (P<0.05). Liver alanine aminotransferase (ALT) and alkaline phosphatase (ALP) in S. hasta fasted for two weeks were higher than the other groups. The activities of trypsin, chymotrypsin, α-amylase, and lipase in S. hasta fasted for a week (T1) were higher than control. In addition, the activities of trypsin and chymotrypsin in A. latus fasted for two or three weeks were lower than C and T1 groups. The activity of ALP was increased with increasing FA period in both species. The findings of the present study showed that single-phase FA episodes reduce survival and induce oxidative stress in S. hasta juveniles; meanwhile A. latus juveniles did not show complete compensatory growth after RF episode.

Performance and ruminal and intestinal morphometry of Santa Inês sheep submitted to feed restriction and refeeding.

A study was carried out to evaluate the performance and ruminal and intestinal morphology of Santa Inês sheep subjected to feed restriction followed by refeeding. A total of 40 uncastrated lambs with an approximate age of 120 ± 15days and mean body weight (BW) of 17.04 ± 1.18kg were randomly divided into two groups of BW (20 and 25kg of BW), which were subjected to different levels of feed restriction (0%, 25%, and 40% of feed restriction). For performance variables, six treatments were considered (0, 25%, and 40% of feed restriction for both groups (20 and 25kg of BW)) and five treatments for morphometric variables (ad libitum, 25% and 40% for both groups (20 and 25kg of BW)). All animals were slaughtered with 14weeks of experimentation. During the feed restriction phase, the dry matter intake (DMI), feed efficiency (FE), and average daily gain (ADG) decreased (P < 0.05) as the level of restriction increased. During the refeeding phase, lambs with 20kg of body weight subjected to restriction presented lower (P < 0.05) DMI in the ad libitum treatment. However, lambs with 25kg of body weight under feed restriction presented DMI, FE, and ADG similar (P > 0.05) to the group ad libitum. The final body weight of restricted lambs after refeeding (both groups 20 and 25kg of body weight) was lower (P < 0.05) than lambs feed ad libitum. In relation to morphology, restricted lambs showed greater height ruminal papillae and larger (P < 0.05) area of ruminal absorption and intestinal absorption, especially the lambs under treatment 40% of feed restriction. The feed restriction followed by refeeding in sheep provided partial compensatory gain, in addition, caused morphological changes in the rumen and intestine that allowed greater absorption and possibly compensatory gain in periods of greater refeeding.

Impact of supervised beego, a traditional Chinese water-only fasting, on thrombosis and haemostasis

Beego is a traditional Chinese complete water-only fasting practice initially developed for spiritual purposes, later extending to physical fitness purposes. Beego notably includes a psychological induction component that includes meditation...

Effect of Dietary Methionine Deficiency Followed by a Re-Feeding Phase on the Hepatic Antioxidant Activities of Lambs.

Simple SummaryDietary methionine is closely related to oxidative stress metabolism. Lambs were treated with methionine restriction and subsequent methionine re-feeding. The relationship among dietary methionine pattern, methionine metabolism, and antioxidant reactions was studied by detecting methionine metabolite content and antioxidant expression in order to provide theoretical basis for amino acid nutrition and healthy feeding of lambs.Our objective was to investigate the effect of methionine restriction and resuming supply on liver antioxidant response in lambs. The concentrations of methionine and its metabolites and the expression of the nuclear factor erythroid 2-related factor 2 (Nrf2), a redox sensitive factor, were detected after methionine restriction treatment for 50 days and methionine supply recovery for 29 days. The expression of glutathione (GSH) S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were characterized at the level of transcription and translation. Methionine restriction can directly change the content of methionine and its metabolites in plasma and liver, and affect the redox state of lambs by activating the Nrf2 signaling pathway. Liver tissue can adapt to oxidative environment by upregulating the expression of antioxidant enzymes such as GSH-Px and SOD. Moreover, it was found that there was a lag effect in the recovery of metabolism after methionine supplementation.

T-wave morphology among medically treated patients with Anorexia Nervosa

Anorexia nervosa (AN) has the highest rate of mortality of any psychiatric disorder, and cardiovascular complications occur in up to 80% of patients with AN and account for up to 30% of mortality. A controversy exists as to whether patients with AN are prone to develop electrocardiographic abnormalities related to repolarization.We aim to study previously unexplored T wave morphology markers in medically-treated patients with AN. Fifty-eight patients with AN (32 with restricting type and 26 with binge-eating/purging type) and 82 healthy controls were included in the study. ECGs were conducted under strict conditions and total cosine R-to-T (TCRT) and T-wave morphology dispersion (TMD) were computed according to accepted standards for a random beat and for an averaged beat. Forty-six AN patients were hospitalized (79.3%) during the study for a mean duration of 1.5 ± 1.1 months. AN patients had comparable QTc, TCRT, mean TMD, TMDpre, TMDpost and TCRTc values to those of healthy adults. Flattened T wave occurred slightly more often among AN patients than in controls (1.57 ± 1.23 leads affected compared with 1.11 ± 0.80 leads, respectively, p = 0.017). QTc, TCRT and TMD parameters' values were unaffected by the clinical type of AN.In conclusion, weight-restored AN patients are characterized by T wave flattening, but normal other T wave morphology parameters, which seemingly reflects an overall low risk of repolarization-associated ventricular arrhythmias. Long-term follow-up studies should be conducted to evaluate the prognostic significance of these novel repolarization markers in untreated patients or early in the refeeding phase.

Duration of stunting impacts compensatory growth and carcass quality of farmed milkfish, Chanos chanos (Forsskal, 1775) under field conditions

An 18-months field trial was performed to explore the effect of duration of stunting on growth, digestive enzymes and carcass quality in Chanos chanos. Milkfish fry (weight of 1.25 ± 0.03 g and length of 5.53 ± 0.03 cm) were stocked in earthen ponds of 0.02 ha, in triplicate, for different duration of stunting, viz., 4 months (Treatment-1; T4), 8 months (Treatment-2; T8) and 12 months (Treatment-3; T12) and a normal seed (Control; C) separately. In the stunting phase, fish were stocked at higher stocking density (0.2 million/ha) and fed de-oiled rice bran at sub-optimal level. Post-stunting or re-feeding phase commenced immediately after completion of respective stunting duration and fish were reared for the rest of the period to complete the total rearing period of 18 months. In post-stunting, fish stocking density was adjusted to (5000 pieces/ha) and fed at an optimum level (3%). At the end of stunting phase, the study found a significant reduction in growth, survival, digestive enzymes activity, except protease in the T4 group, and carcass nutrients composition of stunted fish. However, in the initial phase of post-stunting, T8 group exhibited an elevated specific growth rate (5.00 ± 0.092%/day), body weight gain (80.82 ± 1.28 g), amylase (0.585 ± 0.021 U/mg protein), protease (5.48 ± 0.13 U/mg protein), and lipase activity (7.92 ± 0.32 U/mg protein). All stunted fish groups displayed a compensatory growth response in post-stunting, but a complete growth compensation was observed in T8 group, which resulted in better feed conversion ratio (3.03 ± 0.04) feed efficiency ratio (0.33 ± 0.01), protein efficiency ratio (1.91 ± 0.03), survival (91.38 ± 0.07%) and digestive enzyme activities. Similarly, at the end of post-stunting, carcass analysis revealed a complete restoration of nutrients in stunted fish and significantly higher protein content in T8 group. Further, the study found lower meat and higher bone contents in normally reared fish than the post-stunted fish which revealed the carcass quality improvement in post-stunted fish thus indicates superiority of the stunting process over normal rearing. Overall, the study suggests that stunting of milkfish, for 8 months (T8), positively affects its growth, survival, digestive enzyme activities and carcass quality which in turn, shall help to overcome the contemporary challenges in milkfish culture.

Compensatory growth and digestive enzyme activity of Litopenaeus vannamei submitted to feeding restriction in a biofloc system

Feeding restriction is a strategy in shrimp farming management that may promote compensatory growth after feeding is re‐established. This study aims to evaluate the effects of two feeding restriction regimens on the compensatory growth and digestive enzymes activity of Litopenaeus vannamei reared in biofloc system. Juvenile shrimp (0.46 ± 0.18 g) were stocked (320 individuals/m³) in 310 L tanks. The experiment comprised two phases: (a) Feeding Restriction (30 days) when shrimp were submitted to three feeding regimes, Control (fed daily), R1F1 (repetitively fasted one day and fed one day) and R2F1 (repetitively fasted 2 days and fed 1 day); and (b) Refeeding (28 days) when shrimp were fed daily. In the restriction phase, shrimp growth and digestive enzyme activities were reduced in R2F1 and R1F1. However, during the refeeding phase, enzyme activities and feed conversion improve significantly in R2F1 and R1F1. Control group attained higher final weight, but its final biomass was similar to R1F1. Litopenaeus vannamei exhibited partial compensatory growth, probably due to improved feed conversion efficiency driven by increased enzyme activity. It is possible to reduce feeding by 50% (R1F1) in biofloc systems for 28 days, without compromising the biomass produced at the end of a 30‐day refeeding period.

Low 24-hour core body temperature as a thrifty metabolic trait driving catch-up fat during weight regain after caloric restriction.

The recovery of body weight after substantial weight loss or growth retardation is often characterized by a disproportionately higher rate of fat mass vs. lean mass recovery, with this phenomenon of "preferential catch-up fat" being contributed by energy conservation (thrifty) metabolism. To test the hypothesis that a low core body temperature (Tc) constitutes a thrifty metabolic trait underlying the high metabolic efficiency driving catch-up fat, the Anipill system, with telemetry capsules implanted in the peritoneal cavity, was used for continuous monitoring of Tc for several weeks in a validated rat model of semistarvation-refeeding in which catch-up fat is driven solely by suppressed thermogenesis. In animals housed at 22°C, 24-h Tc was reduced in response to semistarvation (-0.77°C, P < 0.001) and remained significantly lower than in control animals during the catch-up fat phase of refeeding (-0.27°C on average, P < 0.001), the lower Tc during refeeding being more pronounced during the light phase than during the dark phase of the 24-h cycle (-0.30°C vs. -0.23°C, P < 0.01) and with no between-group differences in locomotor activity. A lower 24-h Tc in animals showing catch-up fat was also observed when the housing temperature was raised to 29°C (i.e., at thermoneutrality). The reduced energy cost of homeothermy in response to caloric restriction persists during weight recovery and constitutes a thrifty metabolic trait that contributes to the high metabolic efficiency that underlies the rapid restoration of the body's fat stores during weight regain, with implications for obesity relapse after therapeutic slimming and the pathophysiology of catch-up growth.

Metabolic Flexibility: Interplay of Diet Composition and Intermittent Fasting on Healthspan (P08-053-19)

Objectives4:10 periodic fasting schedule is proposed to improve biomarkers of healthspan through metabolic flexibility in mice on both standard and high fat diets. MethodsOur study adopted the 4:10 fasting schedule using the fasting-mimicking diet (FMD) as our model. FMD is a plant-based, low-protein, and low-sugar diet regime implemented for four days every two-week cycle. Its regenerative effect is observed in the refeeding phase following starvation, allowing for the breakdown of cells via increased autophagy. In comparison to stricter fasting regimes such as intermittent fasting, chronic caloric restriction, and periodic fasting, FMD is well-tolerated in the clinical setting. 74 12-month old C57BL/6 mice were randomized into two diet groups: standard diet or high-fat diet. For 4 days out of every fourteen days, the mice were severely caloric restricted and refed with ad-libitum of either standard or high fat diets for the remaining 10 days, matching the controls who were fixed on the ad-libitum diet. The 4:10 fasting schedule was repeated 11 times before the mice were sacrificed. To measure metabolic flexibility, metabolic cages, ELISA, and glucose meters were used. ResultsBody weight and composition, metabolic flexibility, and insulin sensitivity indicate differences between fasting on diet composition. Not only did those on the fasting high-fat diet (FHFD) remain overweight, identical to their HFD controls, insulin sensitivity was also attenuated in FHFD groups. Fasting standard diet (FSD) had a reduction of 5% in body weight and 15% in body fat. Carbohydrate and lipid metabolism differences indicated by the respiratory exchange ratio as well as motor function performance differences further support the positive impact of fasting on SD groups, not HFD groups. Characteristic of positive healthspan biomarkers, reduced leptin and improved insulin sensitivity was observed with FSD, not FHFD. ConclusionsWe found that while the FMD schedule improved healthspan as indicated by biomarkers of healthy aging for mice on the standard diet, it could not counteract the negative health effects of the obesogenic diet. These results demonstrate the importance of not only time of feeding but also diet composition in respect to healthspan. Funding SourcesNational Institute on Aging (NIA) – National Institutes of Health (NIH).

Optimizing the Cell Culture Microenvironment.

The survival, proliferation, and differentiation of cells in culture are determined not only by their intrinsic potential but also by cues provided by the permissive or restrictive microenvironment in which they reside. The robustness and reproducibility of cell culture assays and endpoints relies on the stability of that microenvironment and vigilant attention to the control of variables that affect cell behavior during culture. These often underappreciated variables include, but are not limited to, medium pH and buffering, osmolarity, composition of the gas phase, the timing and periodicity of refeeding and subculture, and the impact of fluctuations in temperature and gas phase composition on frequent opening and closingof incubator doors. This chapter briefly describes the impact of these and other variables on the behavior of cultured cells.

Thiamine content of F-75 therapeutic milk for complicated severe acute malnutrition: time for a change?

Since community-based management of severe acute malnutrition has become the standard of care, the clinical profile of severe acutely malnourished patients admitted to hospitals or inpatient therapeutic feeding centers has changed significantly. These patients are usually very ill and often present with several comorbidities, such as shock, sepsis, and pneumonia. Complicated severe acute malnutrition patients are at risk of thiamine insufficiency, and critically ill patients have higher thiamine requirements. The thiamine content of F-75, the therapeutic milk formula used in the early stabilization phase of refeeding in patients with severe acute malnutrition, seems insufficient. Here, we discuss the need and rationale for a substantial increase in the thiamine content of F-75.

Gluconeogenesis during starvation and refeeding phase is affected by previous dietary carbohydrates levels and a glucose stimuli during early life in Siberian sturgeon (Acipenser baerii).

Gluconeogenesis responses was assessed during a short starvation period and subsequent refeeding in Siberian sturgeon (Acipenser baerii) previously fed different dietary carbohydrates levels and experienced to a glucose stimuli during early life. The sturgeon larvae were previously fed either a high glucose diet (G) or a low glucose diet (F) from the first feeding to yolk absorption (8 to 12 d post-hatching [dph]). Each group of fish was sub-divided into 2 treatments at 13 dph and was fed either a high-carbohydrate diet (H) or a low carbohydrate diet (L) until 20 wk. In the current study, the fish in 4 groups (GL, FL, GH and FH) were experienced to starvation for 21 d following by re-feeding of their corresponding diets for 21 d. Fish were sampled at postprandial 6 and 24 h before starvation (P6h and P24h), starvation 7, 14 and 21 d (S7, S14 and S21) and 1, 7, 14 and 21 d during refeeding (R1, R7, R14 and R21). Plasma samples during refeeding were taken at P6h at each time point. Glycaemia levels, liver and muscle glycogen contents, activities and mRNA levels of hepatic gluconeogenic enzymes were examined. We found that both dietary carbohydrate levels and early glucose stimuli significantly affected the metabolic responses to starvation and refeeding in Siberian sturgeon (P < 0.05). During prolonged starvation, Siberian sturgeon firstly mobilized the liver glycogen and then improved gluconeogenesis when the dietary carbohydrates were abundant, whereas preserved the liver glycogen stores at a stable level and more effectively promoted gluconeogenesis when the dietary carbohydrates are absent to maintain glucose homoeostasis. During refeeding, as most teleostean, Siberian sturgeon failed controlling the activities and mRNA levels of phosphoenolpyruvate carboxykinase cytosolic forms (PEPCK-C), fructose-1,6-bisphosphatase (FBPase), but particularly controlled phosphoenolpyruvate carboxykinase mitochondrial forms (PEPCK-M) activities and mRNA expression of glucose-6-phosphatase (G6Pase, except in GL group). Siberian sturgeon has a full compensatory ability on growth, but this ability would be obstructed by early glucose stimuli when refeeding the low carbohydrate diet after S21.

Methionine supplementation of low-protein diet and subsequent feeding of low-energy diet on the performance and blood chemical profile of broiler chickens

The effects were investigated of supplementing methionine (Met) in a low-crude protein diet (Low-CP+Met) during Days 11–24 post-hatch and subsequent feeding with a low-metabolisable energy diet (Low-ME; –0.31 MJ/kg) during Days 25–42 on the productive performance and blood chemistry profile of broiler chickens. The 1600 broiler chicks were divided into four groups and fed as follows: (1) Control diet; (2) Low-CP (Met deficiency) diet during Days 11–24, then re-feeding with conventional diet; (3) Low-CP+Met diet during days 11–24, then re-feeding with conventional diet; and (4) Low-CP+Met+Low-ME diet (Low-CP+Met diet during Days 11–24, then re-feeding with Low-ME diet). During Days 11–24, the growth performance of the Control group was better than the other groups (P &lt; 0.01), although the Low-CP+Met diet improved bodyweight, feed conversion ratio and improved the protein conversion ratio compare to the Low-CP group (P &lt; 0.01). During the re-feeding phase (Days 25–42), reducing the dietary energy resulted in better growth performance and a better protein conversion ratio and energy conversion ratio than in the Control group (P &lt; 0.05). Triglyceride, very low-density lipoprotein, low-density lipoprotein-cholesterol and total cholesterol in serum were higher, and non-esterified fatty acid was lower in the Control group than those of the Low-CP+Met+Low-ME group (P &lt; 0.05). In conclusion, reducing dietary protein with balanced amino acids during the grower period and subsequent feeding with a low-energy diet promoted productive performance, improved protein utilisation and reduced fat accumulation via increasing lipolysis and/or disruption of the triglyceride transportation in broiler chickens.

The effects of starvation and re-feeding on growth and swimming performance of juvenile black carp (Mylopharyngodon piceus).

We investigated the effects of starvation and re-feeding on growth and swimming performance and their relationship in juvenile black carp (Mylopharyngodon piceus). We measured the specific growth rate (SGR), resting metabolic rate (RMR) and constant acceleration test speed (U CAT, the maximum swimming speed at exhaustion by constant acceleration test with 0.1667cms(-2) rate) in a treatment group (21days of starvation then 21days of re-feeding) and control group (routine feeding) (n=20). Starvation resulted in a 17% decrease in body mass of black carp (P<0.05). After 21days of re-feeding, body mass was greater than that of pre-starvation but still less than that of the control group at 42days. During the re-feeding phase, the SGR of the treatment group was higher than that of the control group (P<0.05). Starvation resulted in a significant decrease in the RMR and U CAT. After 21days of re-feeding, both the RMR and U CAT recovered to the pre-starvation levels. In the control group, individual juvenile black carp displayed strong repeatability of the RMR and U CAT across the measurement periods (P≤0.002). In the treatment group, RMR showed significant repeatability between pre-starvation and re-feeding (P=0.007), but not between pre-starvation and starvation or between starvation and re-feeding. U CAT showed significant repeatability between pre-starvation and starvation (P=0.006) and between pre-starvation and re-feeding (P=0.001), but not between starvation and re-feeding. No correlation or only a weak correlation was found between any two variables of RMR, U CAT and SGR, whereas the increment of the U CAT (ΔU CAT) was negatively correlated with that of SGR during the starvation phase (r=-0.581, n=20, P=0.007) and re-feeding phase (r=-0.568, n=20, P=0.009). This suggested that within individual black carp, there is a trade-off between growth and maintenance (or development) of swimming performance under food-limited conditions.