Daily feeding frequency affects feed intake and body weight management of growing layers

The objective of this study was to investigate the effect of feeding behavior on feed intake and body weight in growing layers and the underlying mechanisms, thereby providing a scientific foundation for optimal feeding practices in growing layers' management. A total of 144 Hy-line brown growing layers of 10 wk old and similar body weight, were divided into 3 treatment groups with different feeding frequency and equal cumulative daily feeding amount: the once-a-day feeding group (F1) was fed at 9:00 am every day, with feeding amount of 150 g/layer; the twice-a-day feeding group (F2) were fed at 9:00 am and 13:00 pm every day, with each feeding amount of 75 g/layer; the 4 times-a-day feeding group (F4) were fed at 9:00 am, 11:00 am, 13:00 pm, and 15:00 pm every day, with each feeding amount of 37.5 g/layer. Pre-experiment lasted for 1 wk and formal experiment lasted for 8 wk. The results indicated that the daily feed intake and body weight were decreased (P < 0.05) while feed conversion ratio was not affected (P > 0.05) as daily feeding times increased. The glandular stomach proportion was significantly increased in twice-a-day feeding group, while liver proportion and ileum length were significantly increased in 4 times-feeding group (P < 0.05). Additionally, 4 times-feeding daily resulted in a significant elevation of blood glucose levels, which may have suppressed feed intake (P < 0.05). In 4 times-feeding group, the plasma triglyceride levels increased as feeding times, accompanied by a notable up-regulation in the mRNA level of appetite-suppressing gene, hypothalamic pro-opiomelanocortin (POMC) and glandular stomach ghrelin. This modulation effectively suppressed the subsequent feed intake and body weight. Therefore, 4 times feeding daily is recommended in growing layers' management, because it reduced the feed cost without affecting the feed conversion efficiency.

Multi-omics unveils tryptophan metabolic pathway as a key pathway influencing residual feed intake in Duroc swine

The genetic trait of residual feed intake (RFI) holds considerable importance in the swine industry. Recent research indicates that the gut microbiota of pigs plays a pivotal role in the manifestation of the RFI trait. Nevertheless, the metabolic pathways involved in the functioning of these microorganisms remain elusive. Thus, based on the ranking of the RFI trait in Duroc pigs, the present study selected the top 10 and bottom 10 pigs as the experimental subjects. The distribution and metabolite differences of cecal microbiota were analyzed using 16S rRNA gene sequencing and liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques. The low RFI cecal group was named LRC, and the high RFI cecal group was named HRC. The results indicate that the LRC group had lower RFI, feed conversion ratio (FCR), average daily feed intake (ADFI) (p < 0.001), and thinner backfat (p < 0.05) compared with the HRC group. We simultaneously recorded the foraging behavior as well, the LRC group had a significant increase in total time spent at the feeder per day (TPD) (p < 0.05) and a significant increase in average feed intake per mins (AFI) and the number of visits to the feeder per day (NVD) compared to the HRC group (p < 0.001). Clostridium_XVIII, Bulleidia, and Intestinimonas were significantly enriched in the LRC group (p < 0.01), while Sutterella, Fusobacterium, and Bacteroides were significantly increased in the HRC group (p < 0.01). In the metabolome, we detected 390 (248 metabolites up and 142 down in the LRC compared with HRC), and 200 (97 metabolites up and 103 down in the LRC compared with HRC) differential metabolites in positive and negative ionization modes. The comprehensive analysis found that in the LRC group, Escherichia and Eubacterium in the gut may increase serotonin content, respectively. Bacteroides may deplete serotonin. We suggest that the RFI may be partly achieved through tryptophan metabolism in gut microbes. In individuals with low RFI, gut microbes may enhance feed efficiency by enhancing host synthesis and metabolism of tryptophan-related metabolites.

Reduced Meal Frequency Decreases Fat Deposition and Improves Feed Efficiency of Growing-Finishing Pigs

An experiment was conducted to examine the effect of meal frequency on growth performance, nutrient digestibility, carcass quality, and lipid metabolism in growing−finishing pigs. Sixty-four Duroc × Landrace × Yorkshire barrows and gilts (26.40 ± 2.10 kg initial body weight) were used in a 112-d experiment in a randomized complete blocked design. The two treatments were the free-access feed group (FA) and the three meals per day group (M3), respectively. The result showed that the average daily feed intake (ADFI) and F: G of the FA group were significantly higher than that in the M3 group during the whole experiment (p < 0.05). Reducing meal frequency also decreased the concentration of triglycerides and urea nitrogen but increased the concentration of insulin and free fatty acids in the blood (p < 0.05). Reducing meal frequency decreased compositions of backfat, belly, and fatty pieces but increased compositions of ham, longissimus muscle, and lean pieces in the carcass (p < 0.05). Greater enzyme activities of ME and FAS and higher mRNA expression of FAS and PPARγ were found in the LM of FA pigs compared with M3 pigs (p < 0.05). In summary, a lower meal frequency improves feed efficiency by regulating lipid metabolism and reducing fat deposition.

A New Approach to Detecting and Measuring Changes in the Feeding Behaviour Habits of Group-Housed Growing–Finishing Pigs

Simple Summary

It is known that feeding behaviour habits (FBHs) influence growing–finishing pigs’ performance and are modified by production conditions on a group scale. However, no methods are available to describe the evolution of the FBHs at the individual level over short- or long-term periods. This work presents two methods, i.e., repeatability (ratio between animal and total variance) and a new non-parametric approach named “maintenance”, which provides information at the individual level by typifying the individuals into classes and quantifying (%) the pigs that show similar FBHs. Both concepts were applied to six consecutive 14-day periods, throughout two trials of group-housed growing–finishing pigs under different environmental conditions and fed different physical feed forms (mash and pelleted). Both repeatability and maintenance indexes showed similar but not identical results, since they provide complementary information at the global and individual levels, respectively. The results indicate that the environmental conditions and physical feed form modified the repeatability and maintenance of most FBHs, except for the average daily feed intake. Moreover, since maintenance provides data at the individual level, this may be an interesting approach in further studies, for example, to analyse the influence of pen hierarchy on FBHs.

Abstract

The present work aims to estimate the methods of repeatability and of a new non-parametric approach based on typifying individuals into classes and quantifying (%) the pigs in a group that show similar feeding behaviour habits (FBHs) in consecutive periods (“maintenance”). Both methods were estimated over six consecutive 14-day periods in two trials of group-housed growing–finishing pigs (n = 60 each). The first trial started in summer and ended in autumn, and pigs were fed a pelleted diet (HT-P). The second trial started in spring and ended in summer, and the same diet was fed mash (TH-M). The average daily feed intake obtained the lowest repeatability and maintenance values, and it progressively decreased as pigs grew, independent of environmental conditions or physical feed form, whereas the maintenance and repeatability of the number of feeder visits and the visit size decreased when environmental conditions changed from temperate to hot, and mash-fed pigs had higher maintenance and repeatability values for the time spent eating than pellet-fed pigs. In conclusion, the new approach (maintenance) is a tool that is complementary to the classic repeatability concept and is useful for analysing the evolution of FBHs across periods of time at the individual level.

The Feeding Behaviour Habits of Growing-Finishing Pigs and Its Effects on Growth Performance and Carcass Quality: A Review

Based on the available data of feeding behaviour habits (FBHs), this work aimed to discuss which type of pig, according to its FBHs, performs better and is more efficient. As pigs grow, average daily feed intake, meal size, and feeding rate increase, whereas small variations or even decreases in time spent eating and daily feeder visits have been reported. Moreover, the sex, breed, space allowance, feeder design, feed form, diet composition, and environmental conditions modify FBHs. On the other hand, the literature indicates the existence of four types of pigs: pigs that eat their daily feed intake in many short meals (nibblers) or in few large meals (meal eaters) combined with eating fast (faster eaters) or slow (slow eaters). The available scientific literature about ad libitum fed pigs suggests that pigs eating faster with bigger meals eat more, gain more weight, and are fatter than pigs eating less, slower, and with smaller meals. However, the feeding rate and the meal size do not influence feed efficiency. In conclusion, studies comparing growing-finishing pigs with similar feed intake, but different feeding rate and meal size are needed to better understand the influence of FBHs on feed efficiency.

Alterations in intestinal microbiota composition coincide with impaired intestinal morphology and dysfunctional ileal immune response in growing-finishing pigs under constant chronic heat stress

Background

Previous studies had shown that short-term acute heat stress (HS) affected the host’s metabolism and intestinal microbiota independent of feed intake (FI) reduction, and long-term calorie restriction caused intestinal morphological injuries and gut microbial alterations. However, research on the effects of constant chronic HS on intestinal microbial composition and the roles of FI reduction played in is limited. This study aimed to investigate the effects of 7-day constant chronic HS on the composition of intestinal microbes in growing-finishing pigs, and its relationship with pigs’ performance, intestinal morphology, and ileal immune response. Twenty-four growing-finishing pigs (Duroc × Large White × Landrace, 30 ± 1 kg body weight) were randomly assigned to three treatments (n = 8), 1) thermal neutral (TN) conditions (25 ± 1 °C) with ad libitum FI, 2) HS conditions (35 ± 1 °C) with ad libitum FI, 3) pair-fed (PF) with HS under TN conditions to discriminate the confounding effects of dissimilar FI, and the FI was the previous day’s average FI of HS. The small intestinal segments (duodenum, jejunum, and ileum) and feces were collected on d 8.

Results

Results indicated that HS drastically declined (P < 0.05) average daily gain (ADG) and average daily feed intake (ADFI) (about 61%) in comparison with TN, and caused hyperpyrexia, meanwhile PF caused hypothermia. Morphological observation by light and electron microscopes showed that both HS and PF treatment decreased (P < 0.05) the villus and microvillus height compared with TN. Additionally, HS increased (P < 0.05) protein expression of heat shock protein 70 in the duodenum, jejunum, and ileum. Furthermore, the expression of tight junction protein zonula occluden-1 (ZO-1) in the duodenum and ileum, and Occludin in the ileum were enhanced (P < 0.05) compared with TN and PF. Moreover, HS significantly enhanced (P < 0.05) the mRNA relative expression of inflammatory cytokines (TLR-2, TLR-4, and tumor necrosis factor-α (TNF-α), IL-6, IL-8, PG1–5, β-defensin 2 (pBD-2)), mucins (mucin-1 and mucin-2) and P65 protein level in the ileal mucosa tissue. Intestinal microbiota analysis by 16S rRNA sequencing showed lower (P < 0.10) α diversity in both HS and PF, and a separated cluster of β diversity among groups. Compared with TN, HS but not PF mainly reduced (FDR < 0.05) Bacteroidetes (phylum), Bacteroidia (class) and elevated the proportions of Proteobacteria (phylum, FDR < 0.05), Bacillales (order, FDR < 0.05), Planococcaceae (family, FDR < 0.05), Kurthia (genus, FDR < 0.05), Streptococcaceae (family, FDR < 0.10) and Streptococcus (genus, FDR < 0.10). Notably, Lactobacillales (order) was decreased (FDR < 0.05) by PF alone. Furthermore, the Spearman correlation analysis indicated that the microbes prevalent in HS were positively (P < 0.05) associated with intestinal morphological injuries indicators and ileal immune response parameters, and the microbes reduced in HS were negatively (P < 0.05) with the performance data.

Conclusions

Intestinal morphological injuries and ileal immune response caused by constant chronic HS independent of FI showed close connections with alterations in intestinal microbiota in growing-finishing pigs.

Feeding frequency affects glucose and lipid metabolism through SIRT1/AMPK pathway in growing pigs with the same amount of daily feed

Eating patterns are associated with obesity and metabolic health. However, the regulating mechanism of different eating patterns on body metabolism are not fully cleare. In this study, a pig model was used to evaluate the effects of feeding frequency on glucose and lipid metabolism and reveal its regulating mechanism. Twenty-four growing barrows were randomly allocated to 1-meal (M1), 3-meal (M3), or 5-meal (M5) per day groups with the same amount of daily feed. GSEA was conducted on the liver to investigate the pathways of different feeding frequencies on the metabolism. The serum glucose, NEFA, VLDL-C levels were higher for M1 group than for M3 and M5 groups, however, the hepatic TRIG level was lower. Liver transcriptome showed that glycolysis/gluconeogenesis and fatty acid metabolism pathways were suppressed with the increase of feeding frequency. The increase of gluconeogenic substrates (glycerol and lactate) and enzymes (PEPCK1 and G6Pase) in liver indicated that hepatic gluconeogenesis was enhanced in the M1 group. AMPK/PPARα signaling associated genes were positively correlated with NEFA and β-HB levels in M1 group, which promoted fatty acid oxidation and ketogenesis in liver. Moreover, compared with M3 and M5 groups, the higher NAD⁺/NADH ratio in the liver of M1 group activated SIRT1, which stimulated the AMPK signaling associated pathways by up-regulating the LKB1 gene. These findings provide evidence for the regulating roles of feeding frequency on glucose and lipid metabolism through SIRT1/AMPK pathway, which greatly contributes to the regulation of energy metabolism through daily eating patterns in animals.

Feeding Frequency Modulates the Intestinal Transcriptome Without Affecting the Gut Microbiota in Pigs With the Same Daily Feed Intake

The objective of this study was to elucidate the impacts of irregular eating patterns on gut microbiota and transcriptomic responses in a pig model with different feeding regimens. The experiment involved 24 growing pigs (Duroc × Landrace × Large White, 48 days of age) which were randomly allocated to one of three feeding patterns: one-meal (M1), three-meals (M3), or five-meals (M5) per day with the same daily feed intake. The results showed that different feeding frequencies had no significant effects on the microbial composition of ileal digesta, colonic digesta, colon mucosa, as well as the concentration of SCFAs in colonic digesta. Mucosa transcriptomic profiling data showed the pathways related to vitamin metabolism were enriched in the ileum and colon of pigs in the pairwise comparison between M3 and M1 groups. On the other hand, the pathways related to lipid metabolism were enriched in the ileum and colon of pigs in the pairwise comparison between M5 and M1 groups. Lastly, the pathways related to protein metabolism were enriched in the colon in the pairwise comparison between M3 and M1 groups, M5 and M1 groups, M5 and M3 groups, while the ileum was not enriched. Differentially expressed genes (DEG) related to metabolism showed that carbohydrate transport was suppressed in the ileum and enhanced in the colon in M5 and M3 groups compared with the M1 group. Compared with the M3 group, carbohydrate transport in the ileum was enhanced in the M5 group, while in the colon was inhibited. With the increase of feeding frequency, the catabolism, biosynthesis, and transport of lipid in the ileum were suppressed, while those in the colon were enhanced. Compared with the M1 group, amino acid transport in the ileum and colon in the M3 group was enhanced. Amino acid catabolism in the ileum in the M5 group was enhanced compared with M1 and M3 groups. In summary, different feeding frequencies affected the transport of carbohydrate, lipid, and amino acid in the ileum and colon, and affected the catabolism and biosynthesis of lipid in the ileum and colon with a low impact on intestinal microbiota.

Reduced Feeding Frequency Improves Feed Efficiency Associated With Altered Fecal Microbiota and Bile Acid Composition in Pigs

A biphasic feeding regimen exerts an improvement effect on feed efficiency of pigs. While gut microbiome and metabolome are known to affect the host phenotype, so far the effects of reduced feeding frequency on fecal microbiota and their metabolism in pigs remain unclear. Here, the combination of 16S rRNA sequencing technique as well as untargeted and targeted metabolome analyses was adopted to investigate the fecal microbiome and metabolome of growing–finishing pigs in response to a biphasic feeding [two meals per day (M2)] pattern. Sixty crossbred barrows were randomly assigned into two groups with 10 replicates (three pigs/pen), namely, the free-access feeding group (FA) and the M2 group. Pigs in the FA group were fed free access while those in the M2 group were fed ad libitum twice daily for 1 h at 8:00 and 18:00. Results showed that pigs fed biphasically exhibited increased feed efficiency compared to FA pigs. The Shannon and Simpson indexes were significantly increased by reducing the feeding frequency. In the biphasic-fed pigs, the relative abundances of Subdoligranulum, Roseburia, Mitsuokella, and Terrisporobacter were significantly increased while the relative abundances of unidentified_Spirochaetaceae, Methanobrevibacter, unidentified_Bacteroidales, Alloprevotella, Parabacteroides, and Bacteroides were significantly decreased compared to FA pigs. Partial least-square discriminant analysis (PLS-DA) analysis revealed an obvious variation between the FA and M2 groups; the differential features were mainly involved in arginine, proline, glycine, serine, threonine, and tryptophan metabolism as well as primary bile acid (BA) biosynthesis. In addition, the changes in the microbial genera were correlated with the differential fecal metabolites. A biphasic feeding regimen significantly increased the abundances of primary BAs and secondary BAs in feces of pigs, and the differentially enriched BAs were positively correlated with some specific genera. Taken together, these results suggest that the improvement effect of a reduced feeding frequency on feed efficiency of pigs might be associated with the altered fecal microbial composition and fecal metabolite profile in particular the enlarged stool BA pool.

Toward Precise Nutrient Value of Feed in Growing Pigs: Effect of Meal Size, Frequency and Dietary Fibre on Nutrient Utilisation

Simple Summary

Feed costs are the most important in swine production. Precise determination of nutritional values of pig diets can help reducing feed costs by reducing security margins for nutrients and therefore provide a more sustainable swine production. In commercial farms, pigs have free access to feed and eat with no limitation according to their natural behaviour. In contrast, during digestibility trials, pigs are restricted in their daily intake of feed, which is distributed in a limited number of meals. The number of meals per day and the amount of feed consumed daily can affect the digestibility of the nutrients, the transit time and the metabolism. To reduce feed costs, by-products are frequently added to diets. Most by-products are rich in dietary fibre, which are known to have negative effects on digestibility. Enzymes can be supplemented in the diet to counteract the negative aspects of dietary fibre, but their efficiency can vary depending on the number of meals per day and the amount of feed consumed daily.

Abstract

Nutritional values of ingredients have been and still are the subject of many studies to reduce security margins of nutrients when formulating diets to reduce feed cost. In most studies, pigs are fed a limited amount of feed in a limited number of meals that do not represent how pigs are fed in commercial farm conditions. With free access to feed, pigs follow their intrinsic feeding behaviour. Feed intake is regulated by satiety and satiation signals. Reducing the feed intake level or feeding frequency can affect digestibility and transit time and induce metabolic changes. To reduce feed costs, alternative ingredients that are frequently rich in dietary fibre are added to diets. Fibre acts on the digestion process and transit time by decreasing energy density and causing viscosity. Various analyses of fibre can be realised, and the measured fibre fraction can vary. Exogenous enzymes can be added to counteract the effect of fibre, but digestive tract conditions, influenced by meal size and frequency, can affect the efficiency of supplemented enzymes. In conclusion, the frequency and size of the meals can affect the digestibility of nutrients by modulating gastrointestinal tract conditions (pH and transit time), metabolites (glucose and short-chain fatty acids) and hormones (glucagon-like peptide 1 and peptide tyrosine tyrosine).

A novel feeding behavior index integrating several components of the feeding behavior of finishing pigs

Describing the feeding behavior of pigs is difficult given the large day-to-day variations observed for a given animal. The objectives of this study were to create an index that integrates the information from several components of feeding behavior in order to account for intra-animal variation within a day and between days, and to evaluate the capability of this index to study the impact of relevant nutritional factors affecting feeding behavior. Feed intake information from 160 pigs during the last 28 d of the growing phase from three studies was used. For each pig, the sum of the absolute values of the deviation areas between the regression line of the relative cumulative feed intake and the observed cumulative feed intake was used to calculate the weekly index measuring the irregularity of feed intake (IIFI). Spearman's correlations of IIFI with the number of daily meals (r = -0.42; P < 0.001), meal duration (r = 0.38; P < 0.01), and feed intake per meal (r = 0.41; P < 0.01) indicate that pigs with high IIFI have fewer meals of longer duration and higher feed intake compared to pigs with low IIFI. This shows that IIFI captures information from several components of feeding behavior. Analysis of variance showed no effect of treatment on feeding behavior for datasets 1 and 2. However, the correlation between IIFI and dietary levels of CP (r = 0.34) indicates that diets high in CP were associated with pigs having more irregular meals. In dataset 3, pig feeding behavior was more regular in control diets than in pigs fed fibrous diets (IIFI; 164 vs. 197, respectively; P < 0.05). Additionally, IIFI was smaller in pigs fed canola by-product diets than in pigs fed wheat by-product diets, indicating that the source of fiber may also influence the feeding behavior of pigs. In most cases, IIFI was more effective at identifying differences in feeding behavior between dietary treatments than conventional feeding behavior variables. These results show the ability of IIFI to integrate information from several conventional components of the feeding behavior of pigs and its potential to successfully evaluate the effect of nutritional factors on feeding behavior.

Behavioral and stress responses to feeding time in pregnant sows under limit-fed regime

We investigated the effect of feeding time on behavior and stress responses in pregnant sows under isocaloric conditions. Twenty-four sows were balanced for parity and randomly assigned to 1 of 3 feeding times. Corn-soybean meal-based diet was fed once at: 0730 (Control, T1), 1130 (T2), and 1530 hours (T3). On average, sows received 7,062 kcal ME/d from 2.20 kg of diet formulated to contain SID Lys/ME of 1.71 g/Mcal. The study was conducted for 28 d (21 d acclimation to the feeding regime and 7 d data collection). Saliva samples were collected every 2 hr for 12 hr in stalls on day 52 of pregnancy. Behavior data were collected 24 hr for 7 d from day 53 of gestating by affixing a remote insights ear tag to each sow. Each sow had 120,960 data points categorized into: "Active," "Feed," or "Dormant". Due to housing constraint, all sows were housed in individual stalls in the same barn presenting a potential limitation of the study. Data were analyzed using PROC MIXED and GLIMMIX procedures of SAS 9.4 for cortisol and behavior data, respectively. Sow was the experimental unit. The area under the curve (AUC) is quantitative evaluation of response as threshold varies over all possible values. A 12-hr cortisol total AUC for sows fed once daily at 1130 hours was reduced relative to sow group fed at 1530 hours (P = 0.046) but similar compared with the control sows (P = 0. 323). The control sows (0730 hours) had reduced total (P < 0.001) and feeding (P = 0.001) activity AUCs relative to sows on 1130 hours but did not differ compared with sows on 1530 hours feeding schedules (P > 0.100). Sows on 1130 hours feeding schedule had greater feed anticipatory activity, 24-hr total activity count, total (P < 0.001) and feeding (P < 0.001) activity AUC compared with sows fed daily at 1530 hours. In conclusion, feeding pregnant sows earlier in the morning (0730 hours) appears to minimize sows' behavior but similar cortisol response. Sows on 1130 hours feeding schedule had greater activities but reduced cortisol concentration, suggesting that elevated sow activity might not necessarily indicate activation of hypothalamic-pituitary-adrenal axis.

Beneficial effects of a decreased meal frequency on nutrient utilization, secretion of luteinizing hormones and ovarian follicular development in gilts

Background

Replacement gilts are typically fed ad libitum, whereas emerging evidence from human and rodent studies has revealed that time-restricted access to food has health benefits. The objective of this study was to investigate the effect of meal frequency on the metabolic status and ovarian follicular development in gilts.

Methods

A total of 36 gilts (Landrace × Yorkshire) with an age of 150±3 d and a body weight of 77.6±3.8 kg were randomly allocated into one of three groups (n = 12 in each group), and based on the group allocation, the gilts were fed at a frequency of one meal (T1), two meals (T2), or six meals per day (T6) for 14 consecutive weeks. The effects of the meal frequency on growth preference, nutrient utilization, short-chain fatty acid production by gut microbial, the post-meal dynamics in the metabolic status, reproductive hormone secretions, and ovarian follicular development in the gilts were measured.

Results

The gilts in the T1 group presented a higher average daily gain (+ 48 g/d, P < 0.05) and a higher body weight (+ 4.9 kg, P < 0.05) than those in the T6 group. The meal frequency had no effect on the apparent digestibility of dry matter, crude protein, ether extract, ash, and gross energy, with the exception that the T1 gilts exhibited a greater NDF digestibility than the T6 gilts (P < 0.05). The nitrogen balance analysis revealed that the T1 gilts presented decreased urine excretion of nitrogen (− 8.17 g/d, P < 0.05) and higher nitrogen retention (+ 9.81 g/d, P < 0.05), and thus exhibited higher nitrogen utilization than the T6 gilts. The time-course dynamics of glucose, α-amino nitrogen, urea, lactate, and insulin levels in serum revealed that the T1 group exhibited higher utilization of nutrients after a meal than the T2 or T6 gilts. The T1 gilts also had a higher acetate content and SCFAs in feces than the T6 gilts (P < 0.05). The age, body weight and backfat thickness of the gilts at first estrous expression were not affected by the meal frequency, but the gilts in the T1 group had higher levels of serum luteinizing hormone on the 18th day of the 3rd estrus cycle and 17β-estradiol, a larger number of growing follicles and corpora lutea, and higher mRNA expression levels of genes related to follicular development on the 19th day of the 3rd estrus cycle.

Conclusions

The current findings revealed the benefits of a lower meal frequency equal feed intake on nutrient utilization and reproductive function in replacement gilts, and thus provide new insights into the nutritional strategy for replacement gilts, and the dietary pattern for other mammals, such as humans.

Effect of heat stress and feeding management on growth performance and physiological responses of finishing pigs

This study aimed to determine whether pig responses to heat stress (HS) were directly due to heat exposure (regardless of feeding level and pattern) or were indirectly due to the reduction of feed intake (FI) and to determine if increasing feeding frequency (splitting heat increments) can improve pig response to HS. A total of 48 pigs (66.1 ± 1.7 kg) were allocated to four groups in three replicates. After 7 d in thermoneutral (TN) conditions (22 °C; period 1 [P1; day -7 to -1]), pigs were placed in either TN or HS (32 °C) conditions for 20 d (period 2 [P2; day 0 to 19]). The diet was provided either ad libitum (AL; 2 distributions/d) or pair-fed (PF8; 8 distributions/d) using HS-AL pigs as the reference group. Thus, the four experimental groups were TN-AL, HS-AL, TN-PF8, and HS-PF8. The daily ration of PF8 pigs was distributed at every 90-min intervals from 0900 to 1930 hours. Data were analyzed using the PROC MIXED procedure with replicate (n = 3), experimental group (n = 4), and their interactions as fixed effects, and the REPEATED statement was used for repeated measures data. Pigs had a similar average daily feed intake (ADFI) during P1 (P > 0.05). In P2, HS-AL and PF8 pigs had lower ADFI (-19%), average daily gain (-25%), and final body weight (-6.1 kg) than TN-AL pigs (P < 0.01). TN-AL pigs had thicker backfat than TN-PF8 pigs (P < 0.05), while the HS pigs had intermediate results. HS pigs had a higher perirenal fat percentage based on the contrast analysis between PF8 pigs (P < 0.05). Thermoregulatory responses of pigs increased with HS exposure but did not differ between HS or between TN groups (P > 0.05). For TN pigs, variation in muscle temperature (Tmuscle) depended on feeding and physical activity, while for HS pigs, Tmuscle gradually increased throughout the day. The Tmuscle of PF8 pigs increased with each additional meal but plateaued earlier for HS-PF8 than TN-PF8 pigs; an increase in Tmuscle per meal was also lower in HS-PF8 than TN-PF8 (P < 0.05). Exposure to HS decreased plasma T3 and T4 (P < 0.05) and increased plasma creatinine (P < 0.05). Between the PF8 groups, HS pigs also had a transient increase in plasma insulin on day 8 (P < 0.05). The effect of HS on FI decreased the growth rate of pigs but there are heat-induced effects, such as altered physiological responses, which might explain the direct HS effects seen in other literature especially in terms of increased adiposity. The increased feed provision frequency in the present study did not improve the HS response of pigs.

Effect of feeding frequency on the growth performance, carcass traits, and apparent nutrient digestibility in geese

This study was conducted to determine the effect of feeding frequency on growth performance, carcass traits, and apparent nutrient digestibility in geese from 28 to 70 D of age. In experiment 1, a total of 240 geese were distributed in a completely randomized design into 4 treatments and 6 replicates of 10 birds each. The treatments were free access to the feeder (ad libitum) and access to the feeder 3, 4, and 5 times daily. Geese fed 3 times daily had a lower (P < 0.05) BW, ADG, and ADFI and a higher (P = 0.064) feed conversion ratio (FCR) from 28 to 41 D of age compared with the other groups. Geese fed 4 times daily had a higher (P < 0.05) ADG and ADFI and a lower (P < 0.05) FCR from 42 to 55 D of age compared with ad libitum fed geese. Geese fed 3 times daily had a higher (P < 0.05) ADG from 56 to 69 D of age than geese fed ad libitum and 4 times daily. No differences (P > 0.05) in BW, ADFI, ADG, and FCR were observed between ad libitum and feeding frequency groups from 28 to 69 D of age. Carcass traits and gastrointestinal development were not affected (P > 0.05) by feeding frequency. In experiment 2, the apparent nutrient digestibility in geese from 71 to 77 D of age fed using different feeding frequencies was determined using the total fecal collection method. Feeding frequency did not affect (P > 0.05) the apparent digestibility of DM, CP, crude ash, calcium, phosphorous, or ether extract in geese. Our study demonstrates for the first time that compensatory growth can be gained by enhancing feed intake when a lower feeding frequency is imposed on geese. Both ad libitum feeding and fixed feeding frequency for 3 to 5 times daily are suitable for geese from 28 to 70 D of age to achieve optimum production.

Feeding behavior of growing and finishing pigs fed different dietary threonine levels in a group-phase feeding and individual precision feeding system

Feeding behavior is an important aspect of pig husbandry as it can affect protein deposition (PD) in pigs. A decrease in plasma threonine (Thr) levels may influence feed intake (FI) due to amino acid imbalance. We set out to study whether different Thr inclusion rates of 70%, 85%, 100%, 115%, and 130% of the ideal Thr:lysine (Lys) ratio of 0.65 in two different feeding programs (individual precision feeding and group-phase feeding could affect pig feeding behavior and consequently PD. Two 21-d trials were performed in a 2 × 5 factorial setup (feeding systems × Thr levels) with 110 pigs in the growing phase [25.0 ± 0.8 kg of body weight (BW)] and 110 pigs in the finishing phase (110.0 ± 7.0 kg BW), which correspond to 11 pigs per treatment in each trial. Pigs were housed in the same room and fed using computerized feeding stations. The total lean content was estimated by dual x-ray absorptiometry at the beginning (day 1) and the end (day 21) of the trial. Multivariate exploratory factor analysis was performed to identify related variables. Confirmatory analysis was performed by orthogonal contrasts and Pearson correlation analysis. Graphical analysis showed no difference in feeding patterns between feeding systems during the growing or finishing phase. Pigs exhibited a predominant diurnal feeding, with most meals (73% on average) consumed between 0600 and 1800 h. Exploratory factor analysis indicated that feeding behavior was not related to growth performance or PD in growing or finishing pigs. Changes in feeding behavior were observed during the growing phase, where increasing dietary Thr resulted in a linear increase in the FI rate (P < 0.05). During the finishing phase, the duration of the meal and FI rate increased linearly as dietary Thr increased in the diet (P < 0.05). These changes in feeding behavior are, however, correlated to BW. In conclusion, the exploratory factor analysis indicated that feeding behavior had no correlation with growth performance or protein and lipid deposition in growing or finishing pigs. Dietary Thr levels and feeding systems had no direct effect on FI.

Transcriptomic Responses in the Livers and Jejunal Mucosa of Pigs under Different Feeding Frequencies

Simple Summary

Nutrition management strategies are closely related to body development and health, and feeding frequency affects pig feed intake, feed efficiency, body composition, and growth performance. However, the effect of feeding one time daily and two times daily on the intestine has been given less attention. In this study, we investigated the transcriptomic responses induced in the livers and jejunal mucosa of growing pigs by daily feeding schedules. We found that when compared with feeding once daily, two times feeding had no significant effect on the growth performance of growing pigs with the same average daily feed intake. A two meals regimen reduced the concentration of triglycerides in serum and liver, affected the body metabolism by promoting lipid transport, lipogenesis, fatty acid oxidation, chylomicron formation and transport, gluconeogenesis, and inhibiting adipocyte differentiation. These findings support the idea that different feeding regimens could affect lipid metabolism and can be effective in nutritional strategies against metabolic dysfunction.

Abstract

Feeding frequency in one day is thought to be associated with nutrient metabolism and the physical development of the body in both experimental animals and humans. The present study was conducted to investigate transcriptomic responses in the liver and jejunal mucosa of pigs to evaluate the effects of different feeding frequencies on the body’s metabolism. Twelve Duroc × Landrance × Yorkshire growing pigs with an average initial weight (IW) of 14.86 ± 0.20 kg were randomly assigned to two groups: feeding one time per day (M1) and feeding two times per day (M2); each group consisted of six replicates (pens), with one pig per pen. During the one-month experimental period, pigs in the M1 group were fed on an ad libitum basis at 8:00 am; and the M2 group was fed half of the standard feeding requirement at 8:00 am and adequate feed at 16:00 pm. The results showed that average daily feed intake, average daily gain, feed:gain, and the organ indices were not significantly different between the two groups (p > 0.05). The total cholesterol (T-CHO), triglyceride (TG), high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C) concentrations in the serum, and the TG concentration in the liver in the M2 groups were significant lower than those in the M1 group, while the T-CHO concentration in the liver were significant higher in the M2 group (p < 0.05). Jejunal mucosa transcriptomic analysis showed the gene of Niemann-Pick C1-Like 1 (NPC1L1), Solute carrier family 27 member 4 (SLC27A4), Retinol binding protein 2 (RBP2), Lecithin retinol acyltransferase (LRAT), Apolipoprotein A (APOA 1, APOA 4, APOB, and APOC 3) were upregulated in the M2 group, indicating that fat digestion was enhanced in the small intestine, whereas Perilipin (PLIN1 and PLIN2) were downregulated, indicating that body fat was not deposited. Fatty acid binding proteins (FABPs) and Acetyl-CoA acyltransferase 1 (ACAA1) were upregulated in the M2 group, indicating that two times feeding daily could promote the oxidative decomposition of fatty acids. In conclusion, under the conditions in this study, the feeding frequency had no significant effect on the growth performance of pigs, but affected the body’s lipid metabolism, and the increase of feeding frequency promoted the fat digestion in the small intestine and the oxidative decomposition of fatty acids in the liver.

Effect of feeding frequency on growth performance, nutrient digestibility, diarrhea incidence and blood profiles in weaning pigs

An experiment was conducted to evaluate the effect of feeding frequency on growth performance, nutrient digestibility, diarrhea incidence and blood profiles in weaning pigs. Piglets (264) (Average BW, 7.6 kg), were allotted to 2 treatments with 6 replicated pens (22 animals per pen; 11 males and 11 females) in a randomized complete block design based on body weight. Equal amount of diet was provided to all the animals. They were fed an early weaning diet for 14 d and a late weaning diet for 14 d. The control group was fed the diet twice (at 0700 and 1900 h) per day and treatment group was fed the diet four times (at 0700, 1100, 1500 and 1900 h) per day. The change of feeding frequency did not affect feed intake, body weight gain and gain to feed ratio. With increase in the feeding frequency, blood cortisol concentration was not changed. Also, in leptin and ghrelin analysis, there was no significant difference between treatments. Likewise, dry matter digestibility and diarrhea incidence showed no significant difference. In conclusion, the change of feeding frequency in weaning pigs did not affect the growth performance, nutrient digestibility, diarrhea incidence and blood profiles.

Effect of feeding frequency and sow parity based on isocaloric intake during gestation on sow performance

The aim of this study was to investigate the effect of feeding frequency and sow parity based on same rate of maintenance energy intake during gestation on sow performance. One hundred and seventy-seven sows [Topigs Norsvin 70, Landrace × Large White, Topigs Norsvin USA, Burnsville, MN; parity 3.80 ± 0.16; initial BW = 211.34 ± 3.37 kg; backfat (BF) 13.57 ± 0.54 mm] were blocked by parity, balanced for BW, and randomly assigned to 1 of 3 treatments in a randomized complete block design. Treatments included sows fed corn-soybean meal-based diet 1× daily at 0730 h (control, T1), 2× daily [half ration at 0730 and 1530 h (T2)], or 3× daily [a third portion at 0730, 1130, and 1530 h (T3)], with daily feed quantity kept at 1.25 × maintenance energy intake [100 × (BW)0.75] kcal ME/d. Treatments were imposed from day 30 of gestation. Sows received on average 6,921, 7,129, and 7,399 kcal ME/d from days 30 to 60, days 61 to 90, days 91 to 109 of gestation, respectively. Feeding frequency during gestation had no effect on lactation ADFI (P > 0.10). Sows fed 3× daily during gestation had improved lactation G:F (P = 0.040) compared with sows fed 2× but similar to control sows (P = 0.338). Treatment did not alter BW or BW variations during gestation, lactation, or from days 30 to wean (P > 0.10). Sows fed 2× daily had tendency to gain BF from day 30 to day 109 of gestation (P = 0.053) but tended to lose BF during lactation (P = 0.091) relative to the control sows. Feeding frequency (2× and 3× daily) tended to increase the number of piglets weaned by 0.40 (P = 0.056) and 0.53 (P = 0.098) piglets, respectively, compared with control sows. Sows fed 2× daily during gestation had reduced number of stillborn relative to control sows (P = 0.035). From day 30 to wean, gilts had propensity to lose BF relative to P1+ (P = 0.094), but lost BF compared with P3+ and P6+ sows (P = 0.003). Parity P6+ sows had highest percentage of both 72 h and preweaning piglet mortality than P0, P1+, and P3+ sows (P < 0.05). In conclusion, parity (P6+) had greater lactation BW gain but higher mortalities relative to lower parity sows. Sows fed 2× daily tended to gain BF from days 30 to 109 of gestation and had reduced number of stillborn relative to control sows. It appears that increasing gestation sow feeding frequency from 1× daily to 2× and 3× daily may reduce the number of stillborn and increase litter size at weaning although most of the reproductive traits were not affected.

Effects of time of feeding during gestation on sow's performance1

The aim of this study was to investigate the effect of different feeding time regimes given similar energy intake per kilogram live BW0.75 during gestation on sow's performance. One hundred and seventy-four sows [Topigs TN 70 (Landrace × Large White, Topigs USA); parity 3.81 ± 0.16; initial BW = 211.57 ± 3.34 kg; backfat (BF) 13.70 ± 0.42 mm] were blocked by parity, farrowing date, balanced for BW and randomly assigned to 1 of 3 treatments in a randomized complete block design. Treatments included sows fed corn-soybean meal-based diet once at [0730 (control, T1), 1130 (T2), or 1530 h (T3)], with daily feed quantity kept at 1.25× maintenance energy intake [100 × (BW)0.75] kcal ME/d. Sows received 6,758, 7,434, and 8,110 kcal ME/d from days 30 to 60, days 61 to 90, days 91 to 109 of gestation, respectively. The gestation diet was formulated to contain 3,379 kcal of ME/kg, 0.70% Ca, 0.61% total P, 0.58% SID Lys, 0.26% SID Met, 0.45% SID Thr, 0.12% SID Trp, and 0.48% SID Met+Cys. Body weight and BF were recorded on days 30, 60, 90, and 109 of gestation, 24 h after farrowing and at weaning. Results showed that feeding times evaluated did not alter BW changes from day 30 to day 109 of gestation (P = 0.81) or from day 30 to weaning (P = 0.87). Similarly, feeding sows daily at 1130 h did not influence BF gains and sow reproductive performance relative to the control sows (P > 0.10). Sows fed once daily at 1530 h gained more BF compared with the control (3.69 ± 0.47 vs. 2.12 ± 0.50 mm, P = 0.04) from day 30 to day 109 of gestation. From day 30 of gestation to weaning, treatments did not influence BF gain (P = 0.24). Feeding sows daily meal at 1530 h had propensity to increase (P = 0.09) the number of piglets weaned by 0.54 piglets compared with the control sows. In conclusion, the present study demonstrated that feeding pregnant sows at 1530 h altered energy and nutrient metabolism improving their BF gain and exhibited a potential to increase the number of weaned piglets compared with conventional feeding regime.

Feeding behaviour and pre-prandial status affect post-prandial plasma energy metabolites and insulin kinetics in growing pigs fed diets differing in fibre concentration

Variations in feeding behaviour between animals result from individual variations in their metabolism as affected by diet composition. The study aimed to link the within-day dynamics of voluntary feed intake and those of blood metabolites and insulin in growing pigs having ad libitum access to feed and receiving diets differing in dietary fibre levels and aleurone supplementation. A total of forty pigs (body weight: 35 kg) had access to diets provided ad libitum, which differed by fibre content (13 or 18 % neutral-detergent fibre) and aleurone supplementation (0, 2 or 4 g/kg). Feeding behaviour was individually recorded for 1 week. The kinetic of plasma metabolites and insulin was followed for 1 h after a voluntary test meal. Dietary fibre level did not affect the daily feed intake but increased meal size and meal duration. Aleurone supplementation (4 g/kg) decreased the daily feed intake and number of meals. Dietary fibre level only decreased insulin concentration measured 15 min after meal beginning. Aleurone supplementation (4 g/kg) decreased glycaemia in the first hour after the meal and insulinaemia 15 min after the meal. Free access to feed led to high variability in pre-prandial metabolites and insulin concentrations, resulting in different test meal size irrespective of diet composition. Animals were then spread over different profiles combining feeding behaviour and fasted status to explain different profiles of regulation of feed intake. Plasma metabolites and insulin kinetics were affected by diet composition but also by animal characteristics. Individual variability should be considered when diet composition is used to modulate feeding behaviour.

The influence of feeding behaviour on growth performance, carcass and meat characteristics of growing pigs

This study investigated the effect of the feeding behaviour on growth performance, and carcass and meat characteristics of 96 barrows fed ad libitum or restrictively with high or low amino acids (AA) diets according to a 2 × 2 factorial design. The feeding behaviour traits were measured with automated feeders. From 86 kg BW, half of the pigs were given feeds with high indispensable (AA) contents, while the other half received feeds with indispensable AA contents reduced by 9% in early finishing (86-118 kg BW) and by 18% in late finishing (118-145 kg BW). Body lipid and protein retentions were estimated from BW and backfat depth measures recorded at the beginning and end of each period. Pigs were slaughtered at 145 kg BW and carcass and meat quality data were recorded. Phenotypic correlations among feeding behaviours, growth performances, and carcass and meat traits were computed from all the data after adjustment for the effects of feeding treatments. As feeding rate was the behavioural trait most highly correlated with performance and carcass traits, the records of each pig were classified into feeding rate tertiles. Then, the data were statistically analysed using a mixed model, which included feed restriction (FR), AA reduction (AAR), the FR × AAR interaction and the feeding rate tertile as fixed factors, and pen as a random factor. Pigs eating faster (52.1 to 118.9 g/min) had significantly greater final body weights (16%), average daily weight gains (27%), estimated protein gains (22%), estimated lipid retention (46%), carcass weights (16%), weights of lean cuts (14%), weights of fat cuts (21%), proportions of fat in the carcass (14%), and 4% lower proportions of carcass lean cuts than pigs eating slowly (12.6 to 38.2 g/min). Manipulating the eating rate, through management or genetic strategies, could affect feed intake and subsequent growth performance, hence carcass quality, but have little influence on feed efficiency.

Effects of feeding frequency on meat quality traits and Longissimus muscle proteome in finishing pigs

Sixty-four barrows with an initial body weight of 59.8 ± 2.1 kg were allocated to one of the two feeding frequency regimes (had free access to diet and fed two meals per day). Pigs had free access (FA) to feed were fed on an ad libitum basis during the 8-week experimental period. Pigs fed twice daily (M2) were allowed to consume their meals in 2 h. Pigs fed twice daily had lower average daily feed intake (p < 0.01) and average daily gain (p < 0.1), but a greater G:F (p < 0.05) than FA pigs. Lower perirenal fat deposition, hot carcass weight, intramuscular fat content (p < 0.05) and dressing percentage (p < 0.1) were found in M2 pigs compared with FA pigs. Activities of citrate synthase, β-hydroxylacyl-CoA dehydrogenase and lactate dehydrogenase were greater in the Longissimus muscle (LM) of M2 pigs compared with FA pigs (p < 0.05). Proteomic analysis revealed that expression abundances of proteins involved in glucose metabolism, energy production and lipid utilization were upregulated, but expression levels of proteins participating in protein and amino acid metabolism, stress response and redox homeostasis were downregulated in the LM of M2 pigs than those in FA pigs (p < 0.05). In conclusion, the less meal frequency impairs growth rate, has marginal effects on carcass and meat quality traits and affects expression abundances of proteins in the LM of finishing pigs.

A systemic approach to explore the flexibility of energy stores at the cellular scale: Examples from muscle cells

Variations in energy storage and expenditure are key elements for animals adaptation to rapidly changing environments. Because of the multiplicity of metabolic pathways, metabolic crossroads and interactions between anabolic and catabolic processes within and between different cells, the flexibility of energy stores in animal cells is difficult to describe by simple verbal, textual or graphic terms. We propose a mathematical model to study the influence of internal and external challenges on the dynamic behavior of energy stores and its consequence on cell energy status. The role of the flexibility of energy stores on the energy equilibrium at the cellular level is illustrated through three case studies: variation in eating frequency (i.e., glucose input), level of physical activity (i.e., ATP requirement), and changes in cell characteristics (i.e., maximum capacity of glycogen storage). Sensitivity analysis has been performed to highlight the most relevant parameters of the model; model simulations have then been performed to illustrate how variation in these key parameters affects cellular energy balance. According to this analysis, glycogen maximum accumulation capacity and homeostatic energy demand are among the most important parameters regulating muscle cell metabolism to ensure its energy equilibrium.

iTRAQ-based proteomic analysis reveals alterations in the liver induced by restricted meal frequency in a pig model

OBJECTIVE

The present study was conducted to investigate the effects of meal frequency on metabolite levels in pig plasma and hepatic proteome by isobaric tags for relative and absolute quantitation (iTRAQ) analysis.

METHODS

Twenty-four pigs (60.7 ± 1.0 kg) consumed the same amount of feed either in 2 (M2, n = 12) or 12 (M12, n = 12) meals per day. After an 8-wk feeding period, plasma concentrations of metabolites and hormones, hepatic biochemical traits, and proteome (n = 4 per group) were measured.

RESULTS

Pigs on the M12 regimen had lower average daily gain and gain-to-feed ratio than pigs fed the M2 regimen. The M2 regimen resulted in lower total lipid, glycogen, and triacylglycerol content in the liver and circulating triacylglycerol concentration than that in the M12 pigs. The metabolic hormone concentrations were not affected by meal frequency, with the exception of elevated fibroblast growth factor 21 concentrations in the M2 regimen compared with the M12 regimen. The iTRAQ-based proteomic analysis revealed 35 differentially expressed proteins in the liver between pigs fed two and 12 meals per day, and these differentially expressed proteins were involved in the regulation of general biological process such as glucose and energy metabolism, lipid metabolism, protein and amino acid metabolism, stress response, and cell redox homeostasis.

CONCLUSION

Altogether, the proteomic results provide insights into the mechanism mediating the beneficial effects of restricted meal frequency on the metabolic fitness.