Ingestive Behavior Research Articles

Bitter taste receptors as sensors of gut luminal contents.

Taste is important in the selection of food and is orchestrated by a group of distinct receptors, the taste G protein-coupled receptors (GPCRs). Taste 1 receptors (Tas1rs in mice and TAS1Rs in humans; also known as T1Rs) detect sweet and umami tastes, and taste 2 receptors (Tas2rs in mice and TAS2Rs in humans; also known as T2Rs) detect bitterness. These receptors are also expressed in extraoral sites, including the gastrointestinal mucosa. Tas2rs/TAS2Rs have gained interest as potential targets to prevent or treat metabolic disorders. These bitter taste receptors are expressed in functionally distinct types of gastrointestinal mucosal cells, including enteroendocrine cells, which, upon stimulation, increase intracellular Ca2+ and release signalling molecules that regulate gut chemosensory processes critical for digestion and absorption of nutrients, for neutralization and expulsion of harmful substances, and for metabolic regulation. Expression of Tas2rs/TAS2Rs in gut mucosa is upregulated by high-fat diets, and intraluminal bitter 'tastants' affect gastrointestinal functions and ingestive behaviour through local and gut-brain axis signalling. Tas2rs/TAS2Rs are also found in Paneth and goblet cells, which release antimicrobial peptides and glycoproteins, and in tuft cells, which trigger type 2 immune response against parasites, thus providing a direct line of defence against pathogens. This Review will focus on gut Tas2r/TAS2R distribution, signalling and regulation in enteroendocrine cells, supporting their role as chemosensors of luminal content that serve distinct functions as regulators of body homeostasis and immune response.

Early perturbations to fluid homeostasis alter development of hypothalamic feeding circuits with context-specific changes in ingestive behavior.

Drinking and feeding are tightly coordinated homeostatic events and the paraventricular nucleus of the hypothalamus (PVH) represents a possible node of neural integration for signals related to energy and fluid homeostasis. We used TRAP2;Ai14 and Fos labeling to visualize neurons in the PVH and median preoptic nucleus (MEPO) responding to both water deprivation and hunger. Moreover, we determined that structural and functional development of dehydration-sensitive inputs to the PVH from the MEPO precedes those of agouti-related peptide (AgRP) neurons, which convey hunger signals and are known to be developmentally programmed by nutrition. We also determined that osmotic hyperstimulation of neonatal mice led to enhanced AgRP inputs to the PVH in adulthood, as well as disruptions to ingestive behaviors during high-fat diet feeding and dehydration-anorexia. Thus, development of feeding circuits is impacted not only by nutritional signals, but also by early perturbations to fluid homeostasis with context-specific consequences for coordination of ingestive behavior.

CREB coactivator CRTC1 in melanocortin‐4 receptor‐expressing cells regulate dietary fat intake

AbstractCyclic adenosine monophosphate‐response element‐binding protein‐1‐regulated transcription coactivator‐1 (CRTC1), a cytoplasmic coactivator that translocates to the nucleus in response to cAMP, is associated with obesity. We previously reported that CRTC1 deficiency in melanocortin‐4 receptor (MC4R)‐expressing neurons, which regulate appetite and energy metabolism in the brain, causes hyperphagia and obesity under a high‐fat diet (HFD). HFD is preferred for mice, and the dietary fat in HFD is the main factor contributing to its palatability. These findings, along with our previous results, suggest that CRTC1 regulates the appetite for dietary fat. Therefore, in this study, we aimed to investigate the dietary fat intake behavior and energy metabolism of MC4R neuron‐specific CRTC1 knockout mice fed soybean oil or lard. CRTC1 deficiency increased the intake of soybean oil and significantly increased body weight gain. Furthermore, obesity induced by soybean oil intake was partially due to leptin resistance. No significant changes in soybean oil intake were observed between young CRTC1‐deficient and wild‐type mice; however, soybean oil intake increased with age. Moreover, lard intake did not significantly affect the body weight. Overall, our findings highlighted the crucial role of CRTC1 in the regulation of spontaneous dietary fat intake. Furthermore, the role of CRTC1 becomes increasingly significant with age.

Preclinical evidence of the effects of sweet flavors: Sweetness increases nicotine intake and seeking.

The influence of early exposure to sweet and fruit flavors on subsequent nicotine use behaviors during adolescence remains poorly understood. To address this gap, we utilized a rodent model to simulate childhood flavor exposure and examine its effects on later nicotine use behaviors. We employed a two-bottle choice paradigm in weanling rats to mimic human childhood flavor exposure. Subsequently, we investigated the impact of early exposure to sweet (saccharin) and cherry fruit (benzaldehyde) flavors on adolescent nicotine use behaviors. This included assessing subsequent nicotine acquisition, maintenance, and seeking behaviors using intraoral flavor and intravenous nicotine self-administration. Our findings reveal that rats exposed to saccharin during early development exhibited altered patterns of nicotine intake and seeking behaviors during adolescence. Specifically, rats demonstrated increased nicotine intake and seeking of saccharin flavored solutions when paired with nicotine, indicating a potential predisposition towards nicotine use following childhood flavor exposure. Intraoral benzaldehyde did not affect nicotine reinforcement in early sessions of self-administration, but significantly decreased nicotine reinforcement during later sessions. Both saccharin exposure alone or in combination with benzaldehyde promoted nicotine reinforcement. No significant sex differences in nicotine-related behaviors were observed. This study highlights the significance of early flavor exposure in shaping adolescent nicotine use behaviors. The findings suggest that childhood exposure to sweet flavors may contribute to heightened susceptibility to nicotine use and addiction later in life. Understanding these early influences is crucial for developing targeted interventions to prevent the onset of nicotine addiction during adolescence. Our study highlights the importance of how sweetness can contribute to and possibly even alter the effects of the flavor itself. The sweetness of a tobacco product does not solely stem from sweeteners, but it is also influenced by other components such as the PG/VG ratio (e.g., higher VG) and the inclusion of flavors associated with sweetness (e.g., vanillin and ethyl maltol). Therefore, sweet-associated constituents in tobacco products should be investigated further to inform regulatory policy. We believe that our findings can inform regulatory decisions on controlling sweet associated constituents in tobacco products.

Association between snack intake behaviors of children and neighboring women: A population-based cross-sectional analysis with spatial regionalization

BackgroundAccumulated evidence indicates that neighborhood environments affect children's health behaviors. However, measuring neighborhood environments remains challenging because there exist strengths and weaknesses both in objective and perceived environment measures. Drawing on a recent conceptual model of how environment, perception, and behavior interact, we hypothesized that neighbors' behavioral similarities indicate the combined influence of physical and social environmental opportunities on specific behaviors. We then examined how these similarities (i.e. the behavioral tendencies of children's adult neighbors) relate to children's obesogenic dietary behaviors. MethodsWe used data for 2275 women and 821 elementary schoolchildren from a 2012–2013 population-based survey in greater Tokyo, Japan. Snack intake was defined as the total consumption of various types of snacks, estimated using a validated self-administered diet history questionnaire. Spatial regionalization, a type of spatial clustering, was used to empirically identify segments that could effectively differentiate regional variation in women's snack intake behaviors. We conducted multiple regression analysis to assess the cross-sectional association between children's snack intake and the mean snack intake of neighborhood women, adjusting for mother's intake. ResultsA 1-g increase in the mean snack intake of neighborhood women was associated with a 0.23-g (95% confidence interval: 0.00–0.45) increase in children's intake, while a 1-g increase in mother's intake was associated with a 0.34-g (95% confidence interval: 0.26–0.41) increase in children's intake. DiscussionThe results suggest that the out-of-home physical and social neighborhood environments may have non-ignorable associations with children's dietary behaviors by offering behavioral opportunities in addition to maternal influence.

8631 Tanycytic TSHR Activation Regulates Blood-Hypothalamus Barrier Plasticity, Ingestive Behavior, Adipose Remodeling, and Body Weight

Abstract Disclosure: L. Cullen: None. H.S. Kannangara: None. R. Witztum: None. J. Burgess: None. S. Miyashita: None. A. Gumerova: None. F. Korkmaz: None. S.L. Sims: None. U. Cheliadinova: None. G. Pevnev: None. O. Moldavski: None. O. Barak: None. S. Rojekar: None. V. Laurencin: None. T. Frolinger: None. T. Yuen: None. K. Goosens: None. W. Zhou: None. V. Ryu: None. M. Zaidi: None. The notion that TSH acts solely on its primary endocrine target, the thyroid gland, has long been challenged (Abe et al., 2003; PMID: 14567913). More recently, however, we and others have used single transcript technology to document, for the first time, Tshr expression in over 173 brain regions and nuclei, particularly hypothalamic tanycytes (eLife, 2022, PMID: 36052994). The latter cells are known to convey metabolic information across the blood-hypothalamus barrier (BHB) and regulate energy homeostasis. To study whether tanycytic TSHRs have a role in the regulation of BHB permeability, ingestive behavior, adipose tissue remodeling and body weight, we first compared BHB vascular permeability of food-deprived and ad libitum-fed Tshr+/- mice and their wild type (WT) littermates. Transmission electron microscopy and immunostaining was used to study the expression of the constitutive tight junction protein claudin-1 and the glycoprotein MECA-32, which are expressed in tanycytes and endothelial cells, respectively. In loss-of-function studies, fasting of Tshr+/- mice and of WT mice significantly increased the organization of tanycytic honeycomb pattern of claudin-1 and MECA-32-associated fenestral diaphragms in the median eminence and arcuate nucleus, suggesting decreased BHB permeability. As a result, peanut butter consumption following fasting was decreased significantly compared to control mice. In gain-of-function studies, intracerebroventricular (ICV) infusions of a highly specific TSHR agonist, MS438, profoundly increased BHB permeability in fasted mice, as evidenced by decreased claudin-1 and MECA-32 immunostaining and significant increases in peanut butter consumption. This was associated with greater loss of fat mass and body weight following food deprivation, as well as increased influx of fatty acids across the BHB, increased NPY expression (as a measure of increased appetite), and increased secretion of ghrelin from the stomach fundus. We further performed c-Fos immunostaining in brain centers regulating ingestive behavior. ICV MS438 significantly decreased c-Fos immunoreactivity in the hypothalamic paraventricular nucleus, arcuate nucleus and the nucleus of the solitary tract. Early studies using CRSIPR/Cas9 to delete Tshrs in tanycytes via ICV injection resulted in reduced body weight following food deprivation. Finally, using PRV152 (injected into fat tissue) and PRV614 (injected into stomach fundus), we colocalized immunostaining in the hypothalamic paraventricular nucleus, and hindbrain raphe pallidus. Collectively, these data establish a new role for tanycytic TSHRs in regulating BHB plasticity, ingestive behavior, adipose tissue remodeling, and body weight through a novel fast-forward circuit involving the hypothalamus, stomach fundus and fat depots. Presentation: 6/3/2024

Physiological responses, ethology, and ingestive behavior of Anglo-Nubiana goats submitted to different air temperatures

The objective of this study was to evaluate the physiological parameters and ingestive behavior of Anglo-Nubian goats as a function of air temperature, as well as the correlation of these variables. Six male goats were distributed in a completely randomized design in a climate chamber. The treatments consisted of four different controlled AT (20, 24, 28 and 32 °C). The physiological responses: heart rate (HR), respiratory rate (RR) and rectal temperature (RT) were collected at three different times of the day (8 am, 12 pm and 4 pm). The behavioral responses evaluated were: lying inactive, standing inactive, feeding, standing ruminating and lying ruminating. The feed intake decreased linearly in the hours of 4–7 AM, according to the increase in AT. The time spent in the lying ruminating activity decreased linearly (P<0.05) with the increase in AT. The intake and the rate of dry matter intake decreased linearly (P<0.05) with the increase in AT and the water intake increased linearly (P<0.05). The overall results provide information that can be used in heat tolerance studies, helping livestock farmers around the world to plan and make decisions. In addition to contributing to the development of strategies, national and international guidelines for mitigation and accurate assessment of thermal stress.

Association of genomically enhanced residual feed intake with performance, feed efficiency, feeding behavior, gas flux, and nutrient digestibility in growing Holstein heifers.

Residual feed intake (RFI), a metric of feed efficiency, is moderately heritable and independent of body size and productivity, making it an ideal trait for investigation as a selection criterion to improve feed efficiency of growing cattle. The objective of this study was to examine the differences in performance, feed efficiency, feeding behavior, gas flux, and nutrient digestibility in Holstein heifers with divergent genomically enhanced breeding values for RFI (RFIg). Holstein heifers (n = 55; BW = 352 ± 64kg) with low (n = 29) or high (n = 26) RFIg were selected from a contemporary group of 453 commercial Holstein heifers. Heifers were rotated between 1 of 2 pens, each equipped with four electronic feed bunks and one pen with a GreenFeed gaseous exchange monitoring (GEM) system. Individual dry matter intake (DMI) and feeding behavior data were collected for 84-d. Body weight (BW) was measured weekly and spot fecal samples collected at weighing. Phenotypic RFI (RFIp) was calculated as the residual from regression of DMI on average daily gain (ADG) and mid-test metabolic BW (BW0.75). A mixed model including the fixed effect of RFIg classification and random effect of group was used to evaluate the effect of RFIg classification on response variables. There were no differences (P > 0.05) in BW and ADG for heifers with divergent RFIg; however, low RFIg heifers consumed 7.5% less (P < 0.05) feed per day. Consequently, low RFIg heifers exhibited a more favorable (P < 0.05) RFIp (-0.196 vs 0.222kg/d, respectively). Low RFIg heifers had 8.7% fewer (P < 0.05) bunk visit (BV) events per day and tended to have a 11.2% slower (P < 0.10) eating rate. Low RFIg heifers had 7.7% lower (P < 0.05) methane (CH4) emissions (g/d), 6.1% lower (P ≤ 0.05) carbon dioxide (CO2) production (g/d), and 5.6% lower (P ≤ 0.05) heat production (Mcal/d) than high RFIg heifers. However, CH4 yield and CO2 yield (g/kg DMI), and heat production per unit DMI (Mcal/kg DMI) did not differ (P > 0.05) between heifers with divergent RFIg. Dry matter and nutrient digestibility did not differ (P > 0.05) between heifers with divergent RFIg. Overall, heifers selected to be more feed efficient exhibited more favorable energy efficiencies and feed efficiency phenotypes. Results suggest that selection based on RFIg provides opportunities to select cattle with favorable feed efficiency phenotypes to increase the economic and environmental sustainability of the cattle industry.

Altered sex differences related to food intake, hedonic preference, and FosB/deltaFosB expression within central neural circuit involved in homeostatic and hedonic food intake regulation in Shank3B mouse model of autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder accompanied by narrow interests, difficulties in communication and social interaction, and repetitive behavior. In addition, ASD is frequently associated with eating and feeding problems. Although the symptoms of ASD are more likely to be observed in boys, the prevalence of eating disorders is more common in females. The ingestive behavior is regulated by the integrative system of the brain, which involves both homeostatic and hedonic neural circuits. Sex differences in the physiology of food intake depend on sex hormones regulating the expression of the ASD-associated Shank genes. Shank3 mutation leads to ASD-like traits and Shank3B −/− mice have been established as an animal model to study the neurobiology of ASD. Therefore, the long-lasting neuronal activity in the central neural circuit related to the homeostatic and hedonic regulation of food intake was evaluated in both sexes of Shank3B mice, followed by the evaluation of the food intake and preference. In the Shank3B +/+ genotype, well-preserved relationships in the tonic activity within the homeostatic neural network together with the relationships between ingestion and hedonic preference were observed in males but were reduced in females. These interrelations were partially or completely lost in the mice with the Shank3B −/− genotype. A decreased hedonic preference for the sweet taste but increased total food intake was found in the Shank3B −/− mice. In the Shank3B −/− group, there were altered sex differences related to the amount of tonic cell activity in the hedonic and homeostatic neural networks, together with altered sex differences in sweet and sweet-fat solution intake. Furthermore, the Shank3B −/− females exhibited an increased intake and preference for cheese compared to the Shank3B +/+ ones. The obtained data indicate altered functional crosstalk between the central homeostatic and hedonic neural circuits involved in the regulation of food intake in ASD.

A meta-analysis on polymorphic trait of taste perception mediated by TAS2R38 genotype.

The objective of this study is to review the association of TAS2R38 polymorphisms and taste phenotypes to bitter compounds (phenylthiocarbamide [PTC]/propylthiouracil [PROP]), and its association among persons who drink alcohol and individuals with smoking behavior. A literature search was carried out in PubMed, ScienceDirect, Cochrane, and Wiley online library databases using the keyword "(Bitter taste receptor genes OR TAS2R38) AND (PROP OR propylthiouracil) AND (PTC OR phenylthiocarbamide)," "(Bitter taste receptor genes OR TAS2R38) AND (alcohol)," "(Bitter taste receptor genes OR TAS2R38) AND (tobacco OR smoker)" to find articles evaluating the association of taste phenotypes and TAS2R38 polymorphisms, and its association among persons who drink alcohol and individuals with smoking behavior. The analysis show that TAS2R38 taster genotype (proline-alanine-valine [PAV] allele) was significantly (OR, 5.88; CI [3.87, 8.95], p < .001) associated with taster phenotype for bitter compounds (PTC/PROP), and TAS2R38 nontaster genotype (alanine-valine-isoleucine allele) was significantly (OR, 6.73; CI [4.57, 9.90], p < .001) associated with nontaster phenotype for bitter compounds. Further, TAS2R38 taster genotypes (PAV homozygotes and heterozygotes) were significantly associated with higher alcohol intake (OR, 5.15; 95% CI [2.66, 9.98]; p < .001) and among individuals with smoking behavior (OR, 1.73; 95% CI [1.24, 2.42]; p = .001). This suggests that TAS2R38 single nucleotide polymorphisms can be identified by clinically assessing taste phenotype status for bitter compounds and can be used as a potential therapeutic target in the prevention and treatment of harmful higher alcohol intake and smoking behavior. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Effect of replacing Tifton 85 hay with Moringa hay (Moringa oleifera L.) on the nutrient metabolism, metabolic profile, and water balance of sheep.

This study aimed to evaluate the effect of replacing Tifton 85 hay (TH) with Moringa hay (MH) on the intake, apparent digestibility, ingestive behaviour, rumen parameters, serum attributes, nitrogen balance, water balance, and urinary attributes of sheep. Thus, 5 rams, ½ Dorper + ½ Santa Inês, that were 12 ± 4 months of age with an initial body weight of 32.8 ± 2.6kg were distributed in metabolic cages in a Latin square design. The experiment lasted 85 days and was divided into five 17-day periods. The animals received rations with increasing replacement (0, 100, 200, 300, or 400g/kg of dry matter in the total diet) of TH for MH. The forage: concentrate ratio of the diets was 40:60. Replacing TH with MH reduced (P < 0.05) the intake of organic matter, crude protein, neutral detergent fibre (NDFap), and total digestible nutrients by sheep. The apparent digestibility of NDFap and the feeding and rumination efficiencies of NDFap were reduced (P < 0.05) when MH replaced TH in the animals' diet. This replacement did not influence (P > 0.05) serum urea, total protein, creatinine, or aspartate aminotransferase in sheep. Replacing TH with MH decreased water intake and excretion (P < 0.05). In addition, nitrogen excretion via urine, urinary creatinine, and nitrogen absorption decreased (P < 0.05) when TH was replaced with MH. However, there was an increase in the sheep's nitrogen retention and urine pH. We recommend replacing 30% TH with MH in the diet of lambs because it does not compromise nutrient metabolism.

Sardines in hot water: Unravelling plastic fibre ingestion and feeding behaviour effects

Small pelagics are small fish species often schooling that mainly feed on planktonic organisms and are foraging species of larger animals. These species have experienced important declines in their wild populations during the last decades. For instance, the decrease of the European sardine (Sardina pilchardus) body condition has had a detrimental impact on its landings, leaving their commercial fishing unprofitable in some Mediterranean areas. The causes for this decline are not clearly established but seems to be mainly related to changes with planktonic communities inducing a switch in their foraging behaviour from particulate-feeding to filter-feeding. Moreover, it has been highlighted that sardines ingest plastic fibres throughout their natural spatial distribution, suggesting this additional pollution as a possible new threat affecting their populations’ health. In this study we developped an experimental setup allowing us to maintain wild fish in captive controlled conditions in order to test the possible factors affecting plastic fibres ingestion in sardines. We demonstrate that sardines ingest fibres from water, and the amount of fibres ingested is highly impacted by their feeding behaviour. Sardines feeding by filtration ingest less food but more plastic fibres (mean = 4.95 fibres/ind; SD = 3.43), compared to sardines that feed by particulate-feeding (mean = 0.6 fibres/ind; SD = 1.04). Moreover, a decrease in sardine body condition factor was detected for filter-feeding individuals, mostly linked to the lower amount of food they ingested rather than to the fibre ingestion itself. Nonetheless, higher water temperature seems to accelerate the pattern of fibre expulsion in filter-feeding sardines. Alltogether, it is suggested that plastic fibres pollution and phytoplanctonic changes under global change, might synergistically act at disturbing the health of this species in wild populations.

Shifting feed delivery time: effects on feeding behavior, milk production, and blood biomarkers in late-lactating dairy cows

Improving the synchronization between the pattern of milk synthesis and nutrient availability throughout the day could enhance production efficiency. In this study, we evaluated the effects of changing feed delivery time on milk production, feeding behavior, and the daily rhythms of blood biomarkers. Eight multiparous Holstein cows housed in a tie-stall barn with controlled environmental conditions were enrolled in a crossover experimental design with three periods of 14 days and three treatments each. Cows were milked twice daily (0530 and 1730 h) and were individually fed with two equal meals of forage and eight equal meals of concentrate during the day. Forage meals were provided at 12-hour intervals either: (i) 5 h before each milking (0030 and 1230 h; BM), (ii) at the end of each milking (0530 and 1730 h; ME), (iii) or 2 h after (0730 and 1930 h; AM). Feed intake and feeding behavior were monitored, and milk production and composition were measured. Blood samples were collected every 4 days at 0700 h and, during the last day of each period, 15 times daily to determine metabolic profiles, hormones, and their daily rhythmicity by the cosinor analysis. Changing forage delivery time did not affect milk yield and dry matter intake. No difference was observed in feeding behavior when expressed relative to the first meal. There were no significant differences in milk component contents and yields. In samples collected at 0700 h, ME had reduced plasma calcium (Ca), magnesium (Mg), and potassium (K) and increased sodium (Na). AM had increased inflammation, as suggested by the greater blood globulin and ceruloplasmin. The patterns of metabolic biomarkers had limited variations when expressed relative to the first forage meal. Nevertheless, the daily rhythms of these biomarkers were remarkably different. Under our conditions, feeding forage meals to cows at different times of the day did not influence productive performance but highlighted the importance of considering the sampling time when interpreting metabolic profiles.

PSIII-10 Flaxseed oil-based supplement alters water consumption and plasma fatty acid profile of beef heifers

Abstract The objective of this study was to determine the effects of a flaxseed oil-based supplement (FlaxLic, New Generations, SD) on reproductive parameters, feeding behavior, and lipid profile in beef heifers. Crossbred Angus heifers [n = 60 body weight (BW) = 397kg ± 5.2 kg) were blocked by BW and antral follicle count and randomly assigned to two supplementation treatments: free-choice commercial lose mineral supplement (CON; n = 30) or free-choice flaxseed oil-based supplement (FLAX; n = 30) for 7 wk. Heifers were individually fed via the Insentec feeding system (Insentec RIC, Hokofarm, Marknesse, Netherlands), where basal diet (TMR) and supplements were provided in separate feeders to measure supplement intake and feeding behavior. Further, water intake and behavior were measured via Insentec water system. Individual intake was compiled over 24 h for each animal. Body weight, transrectal ultrasonography, and blood samples were collected weekly. On wk 5, heifers were enrolled in a fixed-time artificial insemination (FTAI) commercial protocol. Largest follicle diameter (LF) and corpus luteum (CL) presence were recorded weekly and on d of the FTAI protocol (d 0, d 7, and d 0). Pregnancy diagnosis was performed 30 d and 60 d following AI. Blood samples were analyzed for progesterone (P4) by radioimmunoassay (RIA) to determine puberty attainment before wk 5, and fatty acid profile was determined via gas chromatography-flame ionization detection. Heifers with a CL or P4 ≤ 1.0 ng/mL were considered pubertal. Data were analyzed using SAS 9.4. ADG was similar between groups (P = 0.90) but was affected by week (P &amp;lt; 0.01). TMR intake was similar in duration and quantity (P &amp;gt; 0.18) between groups. Supplement intake was greater (P &amp;lt; 0.01) for FLAX (0.73 ± 0.03 kg/d) compared with CON (0.18 ± 0.02 kg/d) and from wk 2 to wk 8 (P = 0.01). Time spent consuming the supplements was greater for FLAX compared with CON heifers (62.65 ± 2.11 vs 0.10 ± 0.11 min/d, respectively) over the entire trial (P &amp;lt; 0.01). Further, FLAX heifers consumed less water than CON heifers (32.2 ± 0.39 vs 33.93 ± 0.35 kg/d, respectively; P = 0.03) and from wk 2 to wk 7 (P = 0.03). LF was not different between groups on any of the days of the protocol (d 0, d 7, d 0; P &amp;gt; 0.20). Additionally, P4 (P ≤ 0.20), puberty attainment by wk 5 (P = 0.24), and pregnancy rates (P &amp;gt; 0.48) were similar between groups. Concentrations of arachidonic acid (3.00 ± 0.24 vs 2.32 ± 0.19 mg/mL; P = 0.04), linoleic (60.11 ± 4.34 vs 40.35 ± 4.04 mg/mL; P = 0.002), αLinolenic (16.73 ± 0.26 vs 15.86 ± 0.23 mg/mL; P = 0.02), and total polyunsaturated fatty acids (PUFA; 130.52 ± 5.97 vs 111.19 ± 5.56 mg/mL; P = 0.02) were greater on wk 8 for FLAX compared with CON heifers. Collectively, these findings did not show evidence that the flaxseed oil-based supplement affects variables that impact reproductive performance. However, it altered the plasma lipid profile, increasing omega-3, arachidonic, and linoleic fatty acids, as well as total PUFA.

PSX-22 Boosting techniques for prediction of dry matter intake of cattle in confinement settings and SHAP analysis on the models’ output

Abstract Measurement of individual dry matter intake (DMI) is critical to improving the management of the beef herd and is necessary to determine the feed efficiency of individual cattle. Combining machine learning models and proxies for DMI (e.g., water intake, body weight, climatic variables) has the potential to replace the need for dedicated feed intake equipment. It would also open the possibility of measuring DMI in situations like grazing where quantifying DMI directly is not possible. In this study, we examined the relationship between DMI, animal variables and environmental variables. In this study, we developed and tested machine learning models based boosting techniques to develop approaches to predict DMI in cattle, using the same data we have previously published results from Random Forest techniques in the past. The dataset included both bulls and steers. The developed models include both regular boosting regression models and random effects boosting models. The regular boosting technique models such as gradient boosting regression, light gradient boosting regression, extreme gradient boosting regression. Similarly, random effects boosting machine learning model Gaussian process boosting (GPBoost) was developed to consider the random effects associated with the intake behavior of the animals. The extreme gradient boosting model outperformed other regular boosting regression models with a r2 of 0.81 and 0.48 on training and testing datasets respectively. However, it does not consider the random effects associated with the longitudinal nature of the animal intake and weather variables and prone to overfitting. GPBoost model variants were tested and developed to avoid overfitting and to incorporate a random effects model, which we propose as the overall best performing model. The GPBoost generalized well on the training and testing datasets with r2 scores of 0.55 and 0.54 respectively. To further understand the model’s performance on the unseen dataset, we used SHAP analysis on the GPBoost. The SHAP analysis revealed that water intake, full body weight and age of the animals contributed significantly to predicting unseen data.

248 Impacts of sprouted barley on the performance and carcass traits in finishing Angus steers

Abstract The growing population, coupled with unpredictable weather patterns, demands that livestock producers think innovatively to improve sustainability. Producers are interested in innovative practices and technology, such as controlled environment farming to sprout cereal grains that can be fed to livestock. However, little research has determined the effects of giving these feeds to finishing beef steers. As such, Angus steers (n = 60) were stratified by body weight (BW; 385 kg ± 10.3) to receive two different diets (n = 30/diet). The control (CON) diet was a traditional finishing ration for the region, whereas the other included 20% (dry matter; DM) sprouted barley (SB) in place of corn silage. Animals were fed for 128 d in pens with Vytelle units to measure intake and feeding behavior. On d 0, 30, 60, 90, and 128 BW, ruminal fluid, and ultrasound measurements were taken. Liver score (LS) and typical carcass data were collected from a commercial harvest facility. Statistical analyses used the MIXED procedure of SAS to assess the main effect of diet for all measurements collected over time. Dry matter intake (DMI), feed efficiency (gain to feed; G:F), ruminal volatile fatty acid (VFA) composition, and feeding behavior were run as repeated measures. No differences (P = 0.37) in BW gain were found between steers receiving different diets, but steers receiving SB had decreased (P &amp;lt; 0.0001) DMI throughout the trial compared with CON. This decrease in DMI drove a diet × day effect (P = 0.004) for G:F such that SB had increased (P ≤ 0.04) G:F on d 0 and 60, but no effect (P ≥ 0.52) was observed at d 90 or 128. Steers receiving the CON diet spent more (P &amp;lt; 0.0001) time at the feed bunk than those receiving the SB diet, which supports the observation that steers receiving the CON had an increased DMI. Ruminal pH, total VFA concentration, acetate:propionate, percent propionate, and percent butyrate were each impacted by diet × day (P ≤ 0.007). The only carcass trait impacted by diet was yield grade (YG), where steers receiving the SB diet had an increased (P &amp;lt; 0.03) YG compared with CON. These results demonstrate that replacing corn silage with SB in the ration of finishing steers has some effect on ruminal VFA composition, DMI, G:F, and USDAYG. Due to decreased DMI, SB steers had increased feed efficiency which could potentially have a positive economic impact for producers. However, additional analysis is needed to further determine if these systems are economically viable in a production setting.

191 Awardee Talk: Characterizing biological processes influencing the efficiency of nutrient utilization in growing cattle

Abstract 2Abstract: Residual feed intake (RFI), a metric of feed efficiency, is moderately heritable and minimally associated with body size and productivity, making it an ideal trait for investigation as a selection criterion to improve feed efficiency of growing cattle. The objective of this research was to characterize the inter-animal variation in biological processes of growing cattle selected to be divergent in RFI. Holstein heifers [n = 55; body weight (BW) = 351 ± 64 kg) with low- (n = 29) or high- (n = 26) genomically enhanced RFI (RFIg) were selected from a contemporary group of 453 heifers. Heifers were assigned to 1 of 2 pens, equipped with electronic feed bunks and a GreenFeed gaseous-exchange measurement system. Individual dry matter intake (DMI) and feeding behavior data were collected for 84-d. Body weight was measured weekly, and spot fecal samples collected at weighing. Phenotypic RFI (RFIp) was calculated as the residual from regression of DMI on ADG and mid-test BW0.75. On d 70 of the study a rumen fluid sample was collected via esophageal tubing. Blood samples were collected and analyzed for complete blood count (CBC). A mixed model including the fixed effect of RFIg classification and random effect of pen was used to evaluate the effect of RFIg classification on response variables. There were no differences (P &amp;gt; 0.05) in BW and ADG for heifers with divergent RFIg; however, low RFIg heifers consumed 7.5% less (P &amp;lt; 0.05) feed per day. Consequently, low RFIg heifers exhibited a more favorable (P &amp;lt; 0.05) RFIp (-0.188 vs 0.211 kg/d, respectively). Low RFIg heifers exhibited more favorable feeding behavior, with 8.7% fewer (P &amp;lt; 0.05) bunk visit events per day and an 11.2% slower (P ≤ 0.05) eating rate. Low RFIg heifers had 12.5% greater (P &amp;lt; 0.05) total rumen volatile fatty acid concentrations than high RFIg heifers, indicating potentially enhanced microbial fermentation and improved efficiency of feed utilization. Low RFIg heifers had 8.2% less (P &amp;lt; 0.05) methane emissions (g/d), 6.3% less (P &amp;lt; 0.05) carbon dioxide production (g/d), and 6.1% less (P &amp;lt; 0.05) heat production (Mcal/d) calculated according to Brouwer (1965) than high RFIg heifers. Dry matter digestibility did not differ (P &amp;gt; 0.05) between heifers with divergent RFIg. Overall, heifers selected to be more feed efficient exhibited more favorable energy efficiencies and feed efficiency phenotypes. To quantify the variation in RFIg explained by feeding behavior, gas flux, digestibility and rumen fermentation, and CBC partial least squares regression models were developed. Feeding behavior accounted for the largest proportion of variation in RFIg (28.8%). Upon sequential addition of gas flux, digestibility and rumen fermentation, and CBC to feeding behavior, 56.3% of the variation in RFIg was accounted for. Identifying the magnitude at which metabolic processes influence inter-animal variation in efficiency of nutrient utilization provides opportunities to discover valuable candidate biomarkers for selection of more feed efficient cattle.

Effects of monensin and a blend of magnesium oxide on performance, feeding behavior, and rumen morphometrics of Zebu beef cattle fed high-starch diets

Abstract This study aimed to evaluate the effects of a blend of different sources of magnesium oxide associated or not with monensin, on productive, ruminal, and nutritional parameters of steers. Eighty-four Nellore steers with an initial body weight (BW) of 367.3 ± 37.9 kg were allocated to one of 28 pens, with three steers per pen. Each pen was considered an experimental unit, and using a completely randomized design with a 2 × 2 factorial arrangement, the following treatments were assigned to each pen: (1) Control (CON) – a basal diet without additive inclusion; (2) Magnesium oxide blend (MG) – basal diet plus a magnesium-based product (pHix-up®, Timab Magnesium, Dinard, France) provided at 0.50% of dry matter (DM); (3) Monensin (MON) – basal diet plus 25 mg/ kg of DM of sodium monensin (Rumensin, Elanco Animal Health, Greenfield, IN); and (4) MG association with MON – basal diet plus MG + MON, at the same doses of the individual treatments. The experimental period lasted 100 days. Blood samples were collected on days 0, 13, and 70 to determine D-lactate levels. Daily feed intake was recorded, and animal ingestive behavior was visually observed on days 66 and 67. On day 70, skeletal muscle tissue samples were obtained through biopsy for gene expression analysis. At the end of the experimental period, carcass ultrasonography was conducted. Subsequently, the steers were slaughtered, and rumen epithelium samples were collected for morphometric analysis. The use of monensin, of magnesium oxide blend, and their interactions, were treated as fixed effects, while the pens were considered as a random effect. Statistical differences were considered when P &amp;lt; 0.05. Steers fed MG-containing diets consumed approximately 0.6 kg more dry matter per day than those fed diets without this additive (P = 0.01; 11.3 vs. 11.9 kg/day). The inclusion of MG in the diet increased (P = 0.02) the average daily gain (ADG). There was a greater Longissimus muscle area (LMA) and LMA per 100 kg of body weight (BW) (P ≤ 0.03) for steers-fed diets with MG. Steers fed MON exhibited reduced mRNA expression of the Atrogin-1 and mTOR compared to steers fed MG + MON diets (MON × MG: P ≤ 0.04). Steers fed MON had 6.9% greater feed efficiency (P = 0.02). Papillae width was lesser for CON than other treatments (MON × MG: P = 0.02). In conclusion, the magnesium oxide blend improved performance and carcass traits in high-energy feedlot diets, while monensin enhanced feed efficiency, suggesting potential for their use as alternatives or complements in beef cattle nutrition.

Mitragynine and morphine produce dose-dependent bimodal action on food but not water intake in rats.

Kratom (Mitragyna speciosa), containing the primary alkaloid mitragynine, has emerged as an alternative self-treatment for opioid use disorder. Mitragynine binds numerous receptor types, including opioid receptors, which are known to modulate food consumption. However, the ability of acute mitragynine to modulate food consumption remains unknown. The current study assessed the effects of acute mitragynine or morphine administration on unconditioned food and water intake in 16 Sprague-Dawley rats. Food and water intake changes were monitored in response to morphine, mitragynine (1.78-56 mg/kg ip), saline, or vehicle controls for 12 h, starting at the onset of the dark cycle. Naltrexone pretreatment was used to examine pharmacological specificity. Both morphine and mitragynine demonstrated a biphasic food intake dose-effect, with low doses (5.6 mg/kg) increasing and high doses (56 mg/kg) decreasing food intake. All morphine doses reduced water intake; however, only the highest dose of mitragynine (56 mg/kg) reduced water intake. Naltrexone attenuated both stimulatory and inhibitory effects of morphine on food intake, but only the stimulatory effect of mitragynine. In conclusion, low doses of mitragynine stimulate food intake via opioid-related pathways, while high doses likely recruit other targets.NEW & NOTEWORTHY This study reveals that morphine and the kratom alkaloid mitragynine produce dose-dependent effects on feeding in rats. Low doses stimulate food intake via opioid pathways, while high doses decrease consumption through nonopioid mechanisms. Morphine potently suppresses water intake at all doses, whereas only high doses of mitragynine reduce drinking. These findings provide novel insights into the complex opioid and nonopioid mechanisms underlying the effects of mitragynine on ingestive behaviors.

Hunger, Satiety, and Their Vulnerabilities.

The psychological states of hunger and satiety play an important role in regulating human food intake. Several lines of evidence suggest that these states rely upon declarative learning and memory processes, which are based primarily in the medial temporal lobes (MTL). The MTL, and particularly the hippocampus, is unusual in that it is especially vulnerable to insult. Consequently, we examine here the impact on hunger and satiety of conditions that: (1) are central to ingestive behaviour and where there is evidence of MTL pathology (i.e., habitual consumption of a Western-style diet, obesity, and anorexia nervosa); and (2) where there is overwhelming evidence of MTL pathology, but where ingestive behaviour is not thought central (i.e., temporal lobe epilepsy and post-traumatic stress disorder). While for some of these conditions the evidence base is currently limited, the general conclusion is that MTL impairment is linked, sometimes strongly, to dysfunctional hunger and satiety. This focus on the MTL, and declarative learning and memory processes, has implications for the development of alternative treatment approaches for the regulation of appetite.