Restricted Feeding Research Articles

Metabolic and productive adaptive response of beef cows to successive short-nutritional challenges

This study aimed to analyze the response of lactating beef cows to repeated short nutritional challenges with their performance parameters and plasma metabolites. Multiparous lactating beef cows were subjected to three repeated nutritional challenges in the fourth month of lactation. Each challenge consisted of a 4-d feed restriction (55 % of their average energy and protein requirements), followed by a 3-d refeeding period (100 % requirements). Cows were classified into two groups differing in their performance (milk yield) and metabolic adaptation [non esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB)] to diet changes (metabolic response, MR): High and Low MR cows, where the High MR cows showed a faster and larger response to diet changes than the Low MR cows (P < 0.001). The loss in milk yield during restriction was the smallest in challenge 1 (P < 0.001). Milk urea increased during restriction in challenges 1 and 2 (P < 0.001). The High MR cows had greater NEFA concentrations than their Low MR counterparts during restrictions, and greater BHB concentrations during the restriction of challenge 2 (P < 0.001). Restriction increased NEFA, BHB (only in the High MR cows) and urea (P < 0.01). During refeeding, both milk yield and plasma metabolites recovered basal values (P > 0.05). These results highlight the ability of beef cows to respond to and recover from successive short-term nutrient restrictions, and that despite a certain degree of sensitization of milk yield may have occurred, there were only minimal changes in the metabolic strategies triggered to cope with repeated underfeeding.

445 Effects of feed restriction on growth, blood chemistry and reproductive performance in replacement gilts

Abstract The practical application of embryo transfer in pigs could benefit from using embryo donors for multiple cycles. Thus, raising the need to investigate feeding strategies for donors which will not be required to recover body condition lost during previous lactation. The objective was to evaluate the effects of temporary feed restriction, from d 6 to 14 of the estrous cycle, on growth, blood variables and reproductive performance in replacement gilts. Replacement gilts (n = 20; TN70, Topigs Norsvin, Oak Bluff, Canada) were assigned equally across 2 feeding regimens following a randomized complete block design where the block was backfat thickness. The feeding regimens were based on the first day of the estrous cycle: CON, recommended feeding levels from d 0 to 14 and a flush feeding (25% above recommended levels) from d 15 until d 21; or RES, CON but with restricted feeding (25% below recommended levels) from d 6 to 14. The CON treatment was based on the recommendations of the Feed Manual TN70 (Topigs Norsvin, 2015). On d 0, 5, 14 and 20 of the cycle, body weight and backfat thickness were measured. On d 21 (detected estrus), gilts were inseminated and on d 27 they were euthanized to collect embryos, ovaries and uterus. The uterus and ovaries were weighed whereas corpora lutea were counted and weighed. Blood serum was collected on d 14, and 20 for chemical analyses. Data were analyzed using the mixed procedure of SAS where each gilt was the experimental unit. Feeding regimens were considered as the fixed effect and backfat block as the random effect. Means were obtained with the LSMEANS statement. No differences (P &amp;gt; 0.05) were observed on growth performance among feeding regimens. However, when comparing the average daily gain (ADG) within feeding regimens between feeding periods, no differences (P &amp;gt; 0.05) were observed among gilts fed CON whereas gilts fed RES showed a decreased (P &amp;lt; 0.05) ADG during d 6 to 14 compared with d 0 to 5 and d 15 to 21. Regarding blood serum variables, gilts fed RES had greater (P &amp;lt; 0.05) total protein and potassium but less (P &amp;lt; 0.05) sodium-to-potassium ratio than gilts fed CON on d 14. On d 20, Gilts fed RES had greater (P &amp;lt; 0.05) cholesterol values than gilts fed CON. No differences (P &amp;gt; 0.05) were observed on the number of corpora lutea, number of embryos collected or on collection efficiency. Similarly, no differences (P &amp;gt; 0.05) were observed on the weight of reproductive organs or on measurements of ovaries among feeding regimens. In conclusion, restricting feed intake of replacement gilts by 25% of the recommendation from d 6 to 14 of the estrous cycle reduced ADG without compromising their reproductive performance.

The Effect of Quantitative Feed Restriction on the Growth Performance of Broiler Chickens

This research investigates the impact of varied levels of feeding and controlled feed restrictions on the growth parameters, and feed efficiency of broiler chickens. The study focuses on weight gain, feed conversion ratio (FCR), and feed consumption. A total of twenty-five (25) broiler chicks were grouped into 5 groups. Group 1 (Control) had ad libitum feeding , and Groups 2-5 had 95% , 90%, 85% , and 80% of ad libitum feeding respectively for four weeks. Results indicate that the group 2, with 95% of ad libitum feeding, exhibited the highest weight gain, less feed conversion ratio (FCR), and higher feed consumption. Result indicates that other groups subjected to feed restriction including the control group, displayed improved FCR values, suggesting enhanced nutrient utilization for growth, less weight, and less feed consumption. The study recommends the adoption of balanced feed restriction strategies for optimizing broiler production, emphasizing the need for continuous evaluation and adaptation of feeding practices for sustainable and economically efficient outcomes. Keywords: Feed restriction, Growth performance, Broiler chickens, Feed efficiency

Stocking density at feeders and drinkers and temporal feed restriction affects dairy cows' drinking behavior

Water is an essential resource for dairy cows and its consumption is closely linked to feed intake. Social competition can lead to changes in drinking behavior, especially for subordinate cows. We studied how changes in stocking density at the feeder (varied between 1 or 2 cows per feeder), and drinker (varied between 6 or 12 cows per drinker) and a temporal feed restriction (14 or 24 h access) impacts drinking in 4 groups of 6 cows each, following a Latin Square design. Within each group of 6 focal cows, we recorded drinking behavior and 2 were identified as most dominant, 2 as most subordinate, and the 2 others as intermediate, based on success in agonistic interactions at the drinker. Cows drank less water when feed availability was restricted (on average 5.3 L/d less ± 3.4; 4.5% average difference). Subordinate cows also spent less time drinking when overstocked (9.3 min/d less ± 6.7; 24.3% difference). During treatments with more competition, cows were more likely to be observed drinking in the hours after the peak in drinking observed for the control treatment. A high level of competition among group-housed animals is considered a welfare problem and can lead to injuries and reduced production. Our findings provide evidence that feed restriction and higher stocking density of cows at the drinker and feeders changes the drinking behavior of cows, with subordinate animals experiencing more pronounced effects.

Abstract P175: The Effect of TRF on Hypertension Development in Male Dahl Salt-Sensitive Rats

Time restricted feeding (TRF), or food consumption restricted to &lt;10 hrs/day, has been shown to improve blood pressure in various cardiometabolic diseases, yet there is limited data on the effect in SS hypertension. The goal of this study was to examine the effect of TRF on disease development in the Dahl SS rat. We hypothesized that implementing TRF during a critical timepoint in disease progression would reduce mean arterial blood pressure (MAP). To study this, femoral catheters were surgically implanted in male Dahl SS rats at 9±0.5 weeks of age (n=5-7/group), allowing for urine and arterial blood sample collection from conscious rats during continual blood pressure recording. After 1 week of recovery, rats either continued a low salt (LS;0.4% NaCl) diet or were switched to a high salt diet (HS;4% NaCl) with ad libitum (ad lib) access for 1 week. At the start of week 2, a subset of rats began TRF, in which food was provided for 8 hrs (10PM-6AM) during their active period for an additional week. Rats meeting the following criteria were included in analysis: pulse pressure &gt; 10 mmHg, baseline MAP of 115-130 mmHg, and a 10-20 mmHg increase in MAP after 1 week on HS. Differences in MAP were analyzed by 2-way ANOVA with Tukey multiple comparisons and data are reported as mean ± SEM. By the end of week 2, HS TRF rats trended toward lower average MAP compared to HS ad lib rats (141.51±3.41 vs 149.49±1.65 mmHg; p=0.07). However, we found that the HS TRF rats had reduced MAP during their active period (6PM-6AM), compared to the HS ad lib rats (142.60±2.99 vs 151.65±1.862 mmHg; p&lt;0.05), but no difference during the inactive period (6AM-6PM). At the end of the study, average MAP was calculated every 4 hrs to identify the timing at which TRF reduced MAP. We found that the HS TRF rats had lower MAP from 6PM to 10PM (134.61±2.34 vs 146.75±1.21 mmHg; p&lt;0.05) and 10PM to 2AM (144.58±2.79 vs 154.70±2.18 mmHg; p&lt;0.05) when compared to the HS ad lib rats. The LS TRF group also had lower pressure from 6PM-10PM compared to the LS ad lib group (124.93±1.19 vs 130.56±0.73 mmHg; p&lt;0.05), suggesting that this time-specific reduction in MAP may be due to fasting, as there were no other differences in MAP within the LS groups. This suggests that TRF may slow progression of hypertension development in the Dahl SS rat, primarily by affecting MAP during the active period. Future studies will examine how TRF affects Na + handling to further understand these time-dependent effects.

Abstract 02: Time restricted feeding reduces kidney fibrosis in diet-induced obesity through limiting kidney CD8+ T cell infiltration

Obesity is a leading cause of chronic kidney disease (CKD). Our lab previously showed that a 20 week diet-induced obesity (DIO) protocol (45% high fat) significantly increased kidney medullary fibrosis in male mice. Further, we found that time restricted feeding (TRF, feeding during 12-hr dark phase only) during the final 2 weeks of the 20-week DIO protocol significantly reduced kidney fibrosis. DIO mice showed significantly greater CD8+ T cells, compared to mice on a normal diet (ND) only during the dark phase. TRF in the DIO mice normalized the CD8+ T cell to that similar to ND mice. We hypothesized that pro-fibrotic CD8+ T cells infiltrate the kidney and mediate damage in the DIO mice. We used anti (a)-CD8 treatment during the final 2 weeks of DIO to deplete all CD8+ T cells. Separate cohorts of ND and DIO mice received control a-IgG treatment during the final 2 weeks of the protocol. DIO mice treated with a-CD8 showed significantly reduced kidney fibrosis compared to DIO mice treated with a-IgG and similar to ND mice treated with a-IgG (assessed by blue trichrome and picrosirius red staining; one-way ANOVA, p=0.018; NDa-IgG vs DIOa-IgG: p=0.033; DIOa-IgG vs DIOa-CD8: p=0.032). We next investigated the intestinal mucosa (IM) as a source of the kidney-infiltrating CD8+ T cells in DIO mice since the IM is one of the primary non-lymphoid sites of T cells in the body. Previous studies have shown that migration of T cells from the IM to the kidney can drive acute kidney injury, but it is unclear if this occurs with chronic models such as DIO. We used the KikumeGreen (KikGr) mouse model to identify migrating cells into the kidney. When KikGR protein is exposed to 408 nm blue light it is photoconverted to a KikRed. We photoconverted the IM at the end of the ND, DIO, and DIO+TRF protocols. Kidneys were analyzed by flow cytometry at 2.5 days post-photoconversion. We detected significantly higher KikRed+ CD8+ T cells in the kidneys of DIO mice compared to ND mice indicating that CD8+ T cells migrate to the kidney from the IM. DIO+TRF mice showed reduced KikRed+ CD8+ T cells in the kidney compared to DIO mice (one-way ANOVA: p=0.006, ND vs DIO: p=0.008; DIO vs TRF: p=0.047). DIO did not have any significant effect on CD4+ T cell migration (one-way ANOVA: p=0.997). This study indicates that DIO induces migration and infiltration of pro-fibrotic CD8+ T cells from the IM to the kidney, while TRF specifically limits migration and infiltration of CD8+ T cells.

Effect of thymol on the efficiency of feed utilization and compensatory growth in severe feed-restricted lambs.

The present study aimed to evaluate the effect of thymol on growth performance and apparent total tract digestibility of nutrients in severely feed-restricted lambs. Twenty-one male Baluchi lambs were randomly blocked by live weight into three groups: control without feed restriction (CON), feed restricted (FR), and feed restricted plus thymol (FR + T). The lambs underwent a four-week feed restriction period followed by four weeks of realimentation. Thymol was administered daily to the FR + T group during the feed restriction period. Average daily gain (ADG), average daily feed intake, feed efficiency (FE), partial efficiency of maintenance (PEM), and residual feed intake (RFI) were measured as growth performance parameters. Results showed that the severe feed restriction had adverse effects on ADG and FE, but improved PEM (P < 0.05). The effects of thymol administration on ADG, FE, PEM, and apparent total tract digestibility were not significant (P > 0.05). However, the lambs that received thymol during the feed restriction period showed a negative RFI during realimentation (P < 0.05). Overall, these findings suggest that feed restriction as well as thymol may have the potential to improve efficiency of feed utilization in growing lambs. However, this positive effect is independent of the improvement in nutrient digestibility.

Long-term Metabolic Dysfunction Programming in Female Mice by Serial Moderate Restriction of a High-fat High-sucrose Diet.

While intermittent fasting leads to weight loss and improved glucose metabolism, food insecurity, the insufficient access to food for a healthy life, is associated with obesity and adverse cardiometabolic health, especially in women. We aimed to characterize the effects of intermittently restricted feeding on energy balance and glucose tolerance in female mice. Female C57BL/6J mice were fed a high-fat, high-sucrose diet and intermittently food restricted to 60% of control littermates' ad libitum intake, starting at weaning and until week 19. Restricted mice were subsequently allowed ad libitum access to the same diet. Body composition and energy balance were measured at weeks 18.5, 19, 30, and 40. At week 42, mice underwent an intraperitoneal glucose tolerance test and plasma appetitive hormones measurements after nutrient gavage. During the food restriction phase, restricted mice accrued lower weight and fat mass than controls despite periodic ad libitum food access. Reintroduction of continuous ad libitum food caused increased food intake during the light phase and increased body mass in restricted mice. Minor differences in body composition-adjusted energy expenditure between groups were observed at week 40. At week 42, glucose tolerance was impaired in restricted mice compared to controls, and trends toward lower levels of postprandial anorexigenic hormones glucagon-like peptide-1 and pancreatic polypeptide were observed. Our findings suggest that repeated intermittent food restriction leads to changes in eating behavior that predispose to glucose intolerance when food is freely available. Future studies are needed to elucidate the specific mechanisms underlying these changes.

Impact of feed efficiency on young beef animals on adult resilience: From field challenge experiments to modelling approaches

The relationship between feed efficiency at young ages and resilience as cows has been examined using an experiment that combines residual feed intake (RFI) evaluation of beef heifers and subsequent dietary challenge as cows. Feed efficiency of 569 heifers of 22 months of age was estimated during a 70-day period. Then a dietary challenge was applied on 303 of these animals after their first calving, half of them being fed 30 % below their expected needs from 10 days after calving up to the start of the grazing period (around mid-April), after which all the animals received the same management. When possible, the animals were kept until third lactation, giving a total of 514 lactations. Dam weight, dam BCS and calf weight were measured regularly, dam milk production was estimated three times during the lactation and resumption of cyclicity was recorded as well. The experimental data were analyzed using linear models including the effects of heifer efficiency (RFI <-0.4 = efficient; RFI >0.4 = inefficient) and interaction of heifer efficiency and diet group. The data were also used to calibrate a herd dynamics model representing management-nutrition and reproduction interactions at animal level. The experiment data showed that the efficient heifers were 18 kg heavier as cows when fed ad libitum (P = 0.04) but no difference was observed when restricted. Within both diets, heifers classified as efficient produced between 6 and 12 % less milk as cows than inefficient heifers depending on the lactation stage (P < 0.01), with a subsequent effect on calf weight. Finally, the resumption of cyclicity was one week shorter for the efficient animals when fed ad libitum but the opposite was observed within the restricted group, representing a complete ovarian cycle difference between diet groups within the efficient class (P = 0.001). In the lifetime modelling approach, two clusters of animals with different characteristics, including RFI, were simulated under both a non-restricted and restricted feeding environment. In this simulation, efficient heifers produced lighter cows with lower intake and higher body reserves from second calving until culling. Non-efficient heifers had better productive (kg of weaned calf) performance as cows independently of environment. The simulated reproductive performance of cows was equal for animals coming from efficient and non-efficient heifers under the non-restricted environment whereas efficient heifers perform better in the restricted environment, especially when parity increases. Both approaches showed that the interplay between efficiency at young ages and short- and long-term resilience depends on the environment. It can be concluded that the selection for efficiency at young ages has a negative impact on lactational performance as cows but not necessarily on reproductive resilience.

Gestating sows with a restricted feed allowance require a longer adaptation period before collecting feces compared with lactating sows in total tract digestibility assessments using index method.

The objective of the present experiment was to determine the minimum adaptation period for total tract digestibility experiments in gestating and lactating sows using the indigestible index method. Five gestating and 5 lactating sows at parities 3 to 5 were used. An indigestible index of 0.5% chromic oxide was supplemented to a diet based on corn and soybean meal. The daily feed allowance for gestating sows was 2kg and 2 equal meals were provided to the sows. Lactating sows were fed 6kg of feed per day in 3 equal meals. After feeding a diet without supplemental chromic oxide for 5 d, index-supplemented diets were provided to the gestating and lactating sows. Feces were collected at 24-h intervals for 9 and 7 d from gestating and lactating sows, respectively. Fecal Cr concentrations increased linearly (P < 0.001) and quadratically (P < 0.001) with collection time in both gestating and lactating sows. Minimum adaptation periods were estimated by one-slope broken-line model. The break point of Cr concentrations in feces was day 7.2 (SE = 0.3) in the gestating sows and day 4.2 (SE = 0.2) in the lactating sows, respectively. Apparent total tract digestibility of dry matter, organic matter, and energy on day 4 was less (P < 0.001) than that on days 8 to 9 in gestating sows fed the experimental diet with a 2-kg feed allowance. In lactating sows fed the experimental diets with a 6-kg feed allowance, the apparent total tract digestibility of dry matter, organic matter, and energy on day 3 was less (P < 0.05) than that on days 5 to 7. In conclusion, at least 8 d of adaptation period are required for gestating sows to determine total tract digestibility using Cr as the indigestible index method whereas 5 d of adaptation period are required for lactating sows. An insufficient adaptation period results in lower digestibility values.

Intake of NFE, Crude Fibre and Extract Eter of Male Kacang Goats in the Realimentation Phase after Experiencing Different Levels of Feed Restriction

This study aims to determine the intake of nitrogen free extract (NFE), crude fiber (CF), and extract eter (EE) of male Kacang goats in the realimentation phase after experiencing different levels of feed restriction. This study used the experimental method Completely Randomized Design (CRD) which consisted of 3 treatments and 5 replications that is T0 livestock without feed restrictions, T1: livestock are limited to 100% of basic life, T2: livestock are limited to 50% of basic life. Variables observed included NFE, crude fiber, and crude fat intake. The results showed that the NFE, CF and EE of male kacang goats in the realimentation phase of the 3 group were not different/ or significant (P &gt; 0.05). The intake of NFE each treatment is a T0 treatment 222,63±18,17; T1 210,12±29,79, and T2 186,72±34,89. The intake of CF (g/e/h) in treatment T0 56,32±2,47; T1 51,94±9,20; and T2 was 49,82±8,79. The intake of EE (g/e/h) in treatment T0 treatment of 10,19±1,10; T1 9,68±1,37; and T2 8,41±1,64. It can be concluded that the intake of NFE, CF and EE in the realimentation phase of livestock restricted feed 100% according to basic life and 50% below the main life is not much different from the Kacang goats which are given normal feed according to their needs.

Scheduled feeding improves sleep in a mouse model of Huntington's disease.

Sleep disturbances are common features of neurodegenerative disorders including Huntington's disease (HD). Sleep and circadian disruptions are recapitulated in animal models, providing the opportunity to evaluate the effectiveness of circadian interventions as countermeasures for neurodegenerative disease. For instance, time restricted feeding (TRF) successfully improved activity rhythms, sleep behavior and motor performance in mouse models of HD. Seeking to determine if these benefits extend to physiological measures of sleep, electroencephalography (EEG) was used to measure sleep/wake states and polysomnographic patterns in male and female wild-type (WT) and bacterial artificial chromosome transgenic (BACHD) adult mice, under TRF and ad lib feeding (ALF). Our findings show that male, but not female, BACHD mice exhibited significant changes in the temporal patterning of wake and non-rapid eye movement (NREM) sleep. The TRF intervention reduced the inappropriate early morning activity by increasing NREM sleep in the male BACHD mice. In addition, the scheduled feeding reduced sleep fragmentation (# bouts) in the male BACHD mice. The phase of the rhythm in rapid-eye movement (REM) sleep was significantly altered by the scheduled feeding in a sex-dependent manner. The treatment did impact the power spectral curves during the day in male but not female mice regardless of the genotype. Sleep homeostasis, as measured by the response to six hours of gentle handling, was not altered by the diet. Thus, TRF improves the temporal patterning and fragmentation of NREM sleep without impacting sleep homeostasis. This work adds critical support to the view that sleep is a modifiable risk factor in neurodegenerative diseases.

Feed Restriction in Angus Steers Impacts Ruminal Bacteria, Its Metabolites, and Causes Epithelial Inflammation

We identified alterations in the ruminal microbiome, metabolome, and epithelial inflammatory response due to moderate feed restriction (FR). Ruminal digesta and epithelial biopsies from seven ruminally cannulated Angus steers were initially collected during ad libitum access to feed (PRE). After a 10 day recovery, steers underwent a 3-day FR period (FRP) at 25% intake of PRE followed by a 15 day recovery (POST) phase with ad libitum access to feed. At the end of FRP and POST, ruminal digesta and epithelial biopsies were collected again for microbial DNA and tissue RNA extraction. RT-qPCR was applied for relative microbial abundance and RNA extraction. Metabolite profiling of digesta was performed via GC-MS. The abundance of Succinivibrio dextrinosolvens, Streptococcus bovis, and Bifidobacteria spp. (N124) was higher (p &lt; 0.05) during FRP than PRE and POST, while Lactobacillus spp. (C25), Escherichia coli (EC42405), Fibrobacter succinogenes, and Megaspheara elsdenii abundances were lower in FRP than PRE (p &lt; 0.05). The TNF and TLR2 mRNA abundance was greater in FRP than PRE (p &lt; 0.05). Among 15 detected amino acids, glutamine, isoleucine, lysine, phenylalanine, threonine, and valine were lower (p &lt; 0.05) in FRP than PRE. Metabolite pathway analysis revealed alterations in amino acid, fatty acid, vitamin, and energy metabolism during FRP (p &lt; 0.05). The mRNA of the proinflammatory genes TNF and TLR2 in the epithelium peaked (p &lt; 0.05) at FRP and remained higher at POST. Results indicated that a short FR influenced ruminal bacteria, reduced concentrations of most metabolites, and triggered an inflammatory response.

The role of food reward in the associations between weight-based discrimination and feeding practices among caregivers of young children

Certain caregiver feeding practices, including restrictive feeding for weight control, restrictive feeding for health, emotion regulation feeding, and reward feeding, are known to negatively influence short- and long-term child eating and health outcomes. Beyond body size, the precise psychosocial characteristics of caregivers more likely to engage in such feeding practices are unknown. In particular, caregivers who have experienced discrimination based on their weight, who have internalized those biased beliefs, or who find food to be very rewarding may be more likely to use restrictive or controlling feeding practices. The present study investigated the associations among experiences of weight-based discrimination, internalized weight bias, and food reward (i.e., reward-based eating drive) with use of restriction for weight control, restriction for health, emotion regulation feeding, and reward feeding in an online US sample of caregivers (M = 35.27 ± 9.08 y/o) of 2–5 year-old children (N = 305). About half (50.8%) of respondents self-identified as women and most as non-Hispanic (88.5%) and White (75.1%). There were significant positive correlations among caregivers' experience of weight-based discrimination, internalized weight bias, and use of all four feeding practices. Regression results showed that caregivers’ food reward moderated the main effect of weight-based discrimination on restrictive feeding for weight control and emotion regulation feeding, such that caregivers who were high in food reward and who experienced discrimination were most likely to engage in these feeding practices. These results can inform interventions aimed at improving child food environments and health.

Effect of feed restriction for Pacific white shrimp Penaeus vannamei in a semi-intensive synbiotic system: Plankton community, growth and economics

The aim of this study was to evaluate the effects of feed restriction on the plankton community, growth and economic variables of Penaeus vannamei culture in a synbiotic system. Two treatments were used: partial feed restriction (FR) and control without restriction (WR). The study was conducted in triplicate using a completely randomized design. The juveniles (1.67 g ± 0.15) were transferred to six lined ponds of 600 m2 (12 shrimp m−2 density, 20 ppt salinity) for 60 days and fed with commercial feed (35% CP). The ponds received organic (synbiotic — rice bran) and inorganic (urea) fertilization. Shrimp zootechnical performance indicated significant difference in feed conversion ratio (FCR), with values of 0.30 and 0.59 in FR and WR, respectively, which shows a reduction of 49.3%. Plankton showed no significant difference, with dominance of Chlorophyta and Protozoan. In the economic analysis, there was only different amount of feed between the treatments, it implied significant differences reducing the effective operating costs by 21.8% and total operating costs by 20.2% in the FR treatment. In addition, FR break-even point was also reduced by 18.8%, however both treatments had equally positive profitability indicators. Therefore, the feed restriction for P. vannamei in synbiotic system at low stocking density is possible, seeing that the shrimp presented total compensatory growth, reducing FCR without altering the other zootechnical performance parameters. It contributed to costs reduction, although it is important to highlight that offering feed in full cycle with low FCR can promote greater returns to the producer (∼ 40%). Hence, feed restriction is recommended, especially in shrimp farms with low working capital.

Validation of an in vivo dual permeability marker technique to characterize regional gastrointestinal tract permeability in mid lactation Holstein cows during short-term feed restriction.

This study evaluated the impact of short-term feed restriction in lactating dairy cows on regional permeability of the gastrointestinal tract (GIT), and the recovery of DMI, ruminal pH, and milk yield. In addition, sampling methods for a novel dual marker technique to characterize total GIT and post ruminal permeability were validated. Six ruminally cannulated lactating Holstein cows were blocked by parity (3 primiparous, 3 multiparous; 189 DIM ± 25.2) and enrolled in a crossover design. Experimental periods included a 5-d baseline phase (BASE), 5-d challenge phase (CHAL), and 2 weeks of recovery (REC1 and REC2). During CHAL cows received either 100% ad libitum feed intake (AL) or 40% of ad libitum feed intake (FR). To assess, total-tract and post-ruminal permeability, equimolar doses of Cr-EDTA and Co-EDTA were infused on d 3 of CHAL into the rumen and abomasum (0.369 mmol/kg BW). Following infusions, total urine and feces were collected every 8 h over 96 h, and blood samples were collected at h 0, 1, 2, 3, 4, 6, 8, 12, 16, 20, 24, 32, 40, 48, and 64. The plasma area under the curve (AUC) for Cr and Co were calculated. By design, DMI for FR was reduced by 60% during CHAL and remained 19% lower than AL during REC1 but was not different from AL in REC2. Mean ruminal pH for FR was greatest during CHAL and the least during REC1, with no differences detected between AL and FR in REC2. The duration that pH was < 5.8 was the least for FR during CHAL and greatest during REC1 which were different from AL and were no longer different between treatments in REC2. Milk yield was the least for FR during CHAL and REC1 and no longer different from AL in REC2. Feed restriction reduced milk fat, protein, and lactose yields by 26, 31% and 31%, respectively. Plasma Cr AUC was 34% greater and Co AUC tended to be 35% greater for FR than AL on d 3 of CHAL. Urinary Cr recovery after 48-h was not affected by treatment; however, urinary Co recovery was 36% greater for FR than AL. Positive correlations between plasma AUC and urinary recovery for Cr and Co were detected. It was determined that blood samples collected at h 2, 8, 20, 40, and 48 could predict the total plasma Cr and Co AUC within 1.9% and 6.2%, respectively. In summary, short-term FR in lactating dairy cows increases permeability of the total GIT and may increase permeability of the post-ruminal regions with more than 60% of the permeability occurring post-ruminally. After FR, cows experienced low ruminal pH and a sustained reduction in milk yield. When utilizing Cr- and Co-EDTA to evaluate regional GIT permeability, plasma AUC can be used as an alternate to urinary Cr and Co excretion. In addition, blood samples collected at h 2, 8, 20, 40, and 48 result in adequate prediction accuracy, at least when comparing GIT permeability for lactating dairy cows exposed to AL and FR.

Betaine and feed restriction as potential mitigation strategies against heat stress in two strains of laying hens

Climate change is increasingly manifesting in temperate regions. Laying hens are highly sensitive to heat stress and mitigation strategies should be implemented to reduce the negative effects. The goal of this experiment was to evaluate the effects of betaine in drinking water (0.55 g/L) and 4 h feed restriction during peak heat stress on laying performance, egg quality, blood gas parameters, body temperature (Tb), and oxidative stress in 2 different breeds of laying hens. Therefore, 448 ISA Brown hens (25 wk) and 448 Lohmann LSL classic laying hens (26 wk) were housed in 128 cages (7 hens/cage). Thermoneutral (TN) data was collected for 21 d before cyclic heat stress (HS) (21d; 32 ± 2°C; 6 h daily). During HS, hens were divided into 4 treatments: 1) feed restriction (FR), 2) betaine supplementation in drinking water (BET), 3) feed restriction and betaine supplementation in drinking water (FR-BET), or 4) control (CON). The effects were evaluated after 1 wk of HS (acute heat stress; AHS) and 3 wk of HS (chronic heat stress; CHS). Laying rate and egg mass (EM) diminished during CHS but decreased more in white than brown hens (2.78% and 1.94%; -1.57% and -0.81%, respectively; P = 0.004) and remained unaltered by BET or FR. During AHS, average daily feed intake (ADFI) increased compared to TN, but the increase was higher in white than brown hens (6.36% and 2.62%, respectively; P = 0.001). Egg shell quality deteriorated during AHS and CHS, but was most affected in white hens, FR or BET did not impact this. Blood pCO2, HCO3- and base excess significantly decreased during AHS and CHS, but pH and iCa were unaltered. Blood glucose increased in white hens during AHS compared to TN (P < 0.001), while plasma malondialdehyde increased in brown hens (P < 0.001). Results indicated that laying hens experienced HS, but breed differences were observed and white hens were generally most affected. FR affected feed conversion ratio negatively during CHS. However, FR and BET could not improve laying performance, egg quality, Tb, or blood parameters during HS.

Unravelling the mechanisms underlying the social interaction effects on the feed efficiency of rabbits

The feed consumption and feeding patterns of group-housed livestock and their productive outputs can be affected by interactions among group members, such as competition for feeder access and aggression. The impact of competition is especially significant when feed restriction is implemented during the fattening stage, a common practice in rabbit farms to reduce mortality from digestive disorders during this period. The overall aim was to quantify the importance of social interaction effects at the genetic and environmental level on feed efficiency, feeding behaviour and social ranking traits in rabbit populations having access to electronic feeders whilst they were housed in groups during fattening. This was done by quantifying novel feeding behaviour (FB) and social ranking (SR) traits and by estimating the genetic parameters and genetic correlations between all combinations of direct and social effects of these traits and residual feed intake (RFI), an indicator of feed efficiency. These effects were estimated in animals fed either ad libitum (AL) or on a time-based feed restriction (R) and were selected for feed efficiency on these feeding regimes for six generations. We found that there were substantial social genetic and social litter effects on RFI and FB traits, manifesting as antagonistic relationships between direct and social genetic effects. These effects were stronger amongst the R, as opposed to the AL animals. Despite these antagonistic relationships, the large social genetic effects resulted in substantial heritable variation available for selection of these traits, and therefore feeding behaviour could be changed by genetic selection, especially for R animals. The indicators of an animal’s SR were also heritable and subject to social genetic effects and therefore may respond to selection. However, the phenotypic population mean would not change, because such traits are context−specific. The animals that took most of the feeding resources and had priority access to the feeder had a higher RFI, that is, they were less efficient, but they made their cage mates more efficient. This is the first time that the genetic correlations between direct effects of RFI and direct effects of FB and SR traits, as well as between social effects of RFI and direct effects of FB traits and SR traits, have been quantified. Results could help to understand the mechanisms by which an animal exerts its influence on the feed efficiency of its cage mates under different feeding regimes and assist in the development of breeding strategies.

Psychopathological and Organic Features of Atypical Anorexia Nervosa in Developmental Age: A Systematic Review.

This study aimed to comprehensively report the epidemiological and clinical features of atypical anorexia nervosa (AAN) in children and adolescents. In May 2024, a systematic review was performed using Medline, Cochrane Library, ClinicalTrials.gov, and relevant websites. Following PRISMA guidelines, 234 articles were screened for studies on DSM-5-defined AAN. A standardized checklist-the JBI critical appraisal tool-was adopted in assessing methodology, and 13 retained studies passed the screening and critical appraisal process for the final review. The Newcastle-Ottawa Scale was utilized to assess the risk of bias in cohort and case-control studies, ensuring a comprehensive evaluation of methodological quality. AAN prevalence in young age groups is 2.8%, with a cumulative 2.8% incidence over 8 years. Incidence is 366 per 100,000 person-years, and the average episode duration is 11.6 months, with a 71% remission rate. Diagnostic persistence for AAN is less stable than other restrictive feeding and eating disorders (FEDs). AAN individuals exhibit higher EDE-Q scores, more severe distress, and distinct BMI differences compared to those with anorexia nervosa and controls. The diagnostic transition from the DSM-IV to the DSM-5 shows that AAN patients are predominantly female, slightly older, and with higher weight. This study yields concrete insights into the features of AAN in the developmental age, highlighting demographic variations, clinical presentations, and treatment outcomes. Recognizing the unique challenges faced by AAN individuals is vital for tailoring effective interventions and improving overall care within the FED spectrum.

The effects of time restricted feeding on age-related changes in the mouse retina

Dietary modifications such as caloric restriction (CR) and intermittent fasting (IF) have gained popularity due to their proven health benefits in aged populations. In time restricted feeding (TRF), a form of intermittent fasting, the amount of time for food intake is regulated without restricting the caloric intake. TRF is beneficial for the central nervous system to support brain health in the context of aging. Therefore, we here ask whether TRF also exerts beneficial effects in the aged retina. We compared aged mice (24 months) on a TRF paradigm (access to food for six hours per day) for either 6 or 12 months against young control mice (8 months) and aged control mice on an ad libitum diet. We examined changes in the retina at the functional (electroretinography), structural (histology and fluorescein angiograms) and molecular (gene expression) level. TRF treatment showed amelioration of age-related reductions in both scotopic and photopic b-wave amplitudes suggesting benefits for retinal interneuron signaling. TRF did not affect age-related signs of retinal inflammation or microglial activation at either the molecular or histological level. Our data indicate that TRF helps preserve some aspects of retinal function that are decreased with aging, adding to our understanding of the health benefits that altered feeding patterns may confer.