Expression of genes involved in energy homeostasis in the duodenum and liver of Holstein-Friesian and Jersey cows and their F1 hybrid

Expression of Genes Encoding Selected Orexigenic and Anorexigenic Peptides and Their Receptors in the Organs of the Gastrointestinal Tract of Calves and Adult Domestic Cattle (Bos taurus taurus)

The regulation of food intake occurs at multiple levels, and two of the components of this process are orexigenic and anorexigenic peptides, which stimulate or inhibit appetite, respectively. The study of the function of these compounds in domestic cattle is essential for production efficiency, animal welfare, and health, as well as for economic benefits, environmental protection, and the contribution to a better understanding of physiological aspects that can be applied to other species. In this study, the real-time PCR method was utilized to determine the expression levels of GHRL, GHSR, SMIM20, GPR173, LEP, LEPR, and NUCB2 (which encode ghrelin, its receptor, phoenixin-14, its receptor, leptin, its receptor, and nesfatin-1, respectively) in the gastrointestinal tract (GIT) of Polish Holstein-Friesian breed cattle. In all analyzed GIT segments, mRNA for all the genes was present in both age groups, confirming their significance in these tissues. Gene expression levels varied distinctly across different GIT segments and between young and mature subjects. The differences between calves and adults were particularly pronounced in areas such as the forestomachs, ileum, and jejunum, indicating potential changes in peptides regulating food intake based on the developmental phase. In mature individuals, the forestomachs predominantly displayed an increase in GHRL expression, while the intestines had elevated levels of GHSR, GPR173, LEP, and NUCB2. In contrast, the forestomachs in calves showed upregulated expressions of LEP, LEPR, and NUCB2, highlighting the potential importance of peptides from these genes in bovine forestomach development.

Butyrate supplementation in the liquid diet of dairy calves leads to a rapid recovery from diarrhea and reduces its occurrence and relapses in the preweaning period

The present study aimed to evaluate the effect of continuous butyrate administration in dairy calves' liquid diet considering diarrhea, metabolic profile, gastrointestinal development, and corporal growth. Immediately after birth, calves were randomly allocated into 2 groups of 62 calves (50 females and 12 males), with access to water and a solid feed ad libitum. The butyrate group (BG) received 4 g/d of sodium butyrate (Admix Easy, Adisseo) diluted in the whole milk, and the control group (CG) received whole milk with no supplementation. Sodium butyrate was administered from d 1 of life until the weaning at 90 d. Feces consistency was assessed daily for the first 30 d of life and characterized by scores from 0 to 4 (0 and 1 for normal, and 2, 3, and 4 for abnormal feces). Diarrhea was diagnosed when the animals had abnormal feces and fever. Morbidity, recurrence, mortality, and lethality data were recorded and compared between the groups. Average daily gain (ADG) and corporal growth (body weight, thoracic perimeter, height at the withers, and croup width) were evaluated weekly, from the first day to d 30, and later at 45, 60, and 90 d of life. Blood samples were taken weekly for up to 30 d to determine the circulating levels of total calcium, phosphorus, chloride, bicarbonate, glucose, β-hydroxybutyrate, and nonesterified fatty acids. The males were euthanized at 15 (n = 6 per group) and 30 d (n = 6 per group) for morphometric, histological, and gene expression analysis of the gastrointestinal tract. The results showed that the BG had a lower rate of morbidity (BG = 30% vs. CG = 50%) and recurrence (BG = 26.7% vs. CG = 60%) of diarrhea than the CG. In addition, the BG had abnormal feces for a shorter period (BG = 4.64 ± 0.47 d vs. CG = 8.6 ± 0.65 d). The ADG tended to be higher in BG than CG up to 30 and 60 d. Metabolic evaluations showed the lowest levels of glucose and highest levels of nonesterified fatty acids in BG. On d 30 of life, rumen papillae length, papilla area, duodenum villus length, and crypt depth were higher in BG than in CG. The duodenal gene expression at 30 d showed that animals with diarrhea episodes that did not receive butyrate had the highest levels of transcripts for the LCT and GLP2 genes. In addition, in different ways, both butyrate and neonatal diarrhea affected the gene expression of IGF1, SLC5A1, and AQP3. These results allow us to conclude that continuous supplementation with sodium butyrate improves gastrointestinal development, reduces the occurrence of diarrhea, and makes clinical conditions milder with faster recovery, favoring a higher ADG in the first 30 and 60 d of life. Based on these results, we conclude that sodium butyrate can be indicated for liquid diet supplementation to accelerate gastrointestinal tract development and prevent severe cases of neonatal diarrhea, tending to improve average daily gain until weaning.

A Longitudinal Study with a Laser Methane Detector (LMD) Highlighting Lactation Cycle-Related Differences in Methane Emissions from Dairy Cows

Reversing climate change requires broad, cohesive, and strategic plans for the mitigation of greenhouse gas emissions from animal farming. The implementation and evaluation of such plans demand accurate and accessible methods for monitoring on-field CH4 concentration in eructating breath. Therefore, this paper describes a longitudinal study over six months, aiming to test a protocol using a laser methane detector (LMD) to monitor CH4 emissions in semi-extensive dairy farm systems. Over 10 time points, CH4 measurements were performed in dry (late gestation) and lactating cows at an Azorean dairy farm. Methane traits including CH4 concentration related to eructation (E_CH4) and respiration (R_CH4), and eructation events, were automatically computed from CH4 measured values using algorithms created for peak detection and analysis. Daily CH4 emission was estimated from each profile’s mean CH4 concentration (MEAN_CH4). Data were analyzed using a linear mixed model, including breed, lactation stage, and parity as fixed effects, and cow (subject) and time point as random effects. The results showed that Holsteins had higher E_CH4 than Jersey cows (p < 0.001). Although a breed-related trend was found in daily CH4 emission (p = 0.060), it was not significant when normalized to daily milk yield (p > 0.05). Methane emissions were lower in dry than in lactation cows (p < 0.05) and increased with the advancement of the lactation, even when normalizing it to daily milk yield (p < 0.05). Primiparous cows had lower daily CH4 emissions related to R_ CH4 compared to multiparous (p < 0.001). This allowed the identification of periods of higher CH4 emissions within the milk production cycle of dairy cows, and thus, the opportunity to tailor mitigation strategies accordingly.

Performance and serum parameters of calves (Bos taurus) subject to milk restriction associated with supplementation with 2-hydroxy-4-(methylthio)butanoic acid

Our aim with this study was to evaluate the consumption, performance, quantitative characteristics of carcasses, biochemical profile, plasma levels of ghrelin and leptin, expression of the receptor for ghrelin (GHS-R1a) in the hypothalamus and duodenum, and the number of goblet cells in the duodenum of calves subjected to milk volume restriction and supplemented with 2-hydroxy-4-(methylthio)butanoic acid (HMTBa). We used 21 Holstein mixed-breed calves, aged between 3 and 15 d with an average weight of 36.8 kg, and housed in pens with troughs for hay, concentrate, and water. The study included two consecutive experimental periods (first period [P1] and second period [P2]) of 21 d each, with 7 d of adaptation to the diet and facilities. The calves were distributed in a completely randomized design in three treatments with seven repetitions. 1) Control: 6 liters of milk/d during P1 and 6 liters of milk/day during P2; 2) RES (milk restriction): 3 liters of milk/day during P1 and 6 liters of milk/day during P2; and 3) RES + HMTBa: 3 liters of milk/day during P1 and 6 liters of milk/day during P2 + 3.3 g of HMTBa/day in both periods. HMTBa was supplied in milk, and the amount of concentrated ration and hay provided and leftovers were recorded daily to estimate dry matter (DM) and crude protein consumption. Mean daily weight gain (DWG), final weight (FW), and feed conversion (FC) were obtained at the beginning and at the end of each 21-d period. Plasma concentrations of ghrelin and leptin, triglycerides, total protein, urea, lactate, creatinine, alkaline phosphatase, and cholesterol were measured for P1 and P2 at the end of each 21-d period. At the end of P2, animals were slaughtered; sections of the duodenum were collected to evaluate the expression of GHS-R1a and quantity of goblet cells; hypothalamus was used to evaluate the expression of GHS-R1a; rumen was used to evaluate the thickness of epithelium and keratin and the density, height, and width of ruminal papillae. In P1, total DM consumption, FW, DWG, glucose, and triglycerides were lower in the RES and RES + HMTBa groups (P < 0.001). In P2, there was an improvement in the FC of the RES + HMTBa group (compared with Control and RES groups) and a lower urea concentration in the RES group (compared with Control and RES + HMTBa groups) (P < 0.001). No differences were observed among groups regarding hormonal concentrations, histological parameters, and GHS-R1a expression in the duodenum and hypothalamus. Therefore, milk restriction combined with HMTBa supplementation promoted greater compensatory gain by a mechanism independent of changes in GHS-R1a expression and hormone levels of ghrelin and leptin.

Association analysis between feed efficiency and expression of key genes of the avTOR signaling pathway in meat-type ducks

Genes involved in the target of rapamycin (TOR) signaling pathway are implicated in nutrient translation, cell proliferation and differentiation, and anabolism, which can affect both growth and feed intake. However, the role of TOR signaling in the regulation of feed intake and feed efficiency in poultry is not clear. In the present study, a total of 1000 ducks, of similar initial weight, were chosen and transferred to individual cages to determine their residual feed intake (RFI) from the age of 21 to 42 days. Subsequently, 60 ducks, which were divided into high (HRFI) and low (LRFI) groups according to their RFI, were chosen to analyze the TOR signaling activities in the liver. The differential expression level of genes involved in the TOR signaling pathway was assayed by the real-time polymerase chain reaction. In the liver, the expression of AKT, avTOR, avLST8, and S6K1 was significantly higher in LRFI ducks than in HRFI ducks; avTOR and AKT were negatively associated with the feed conversion ratio and RFI. Furthermore, PI3K was moderately positively associated with AKT; AKT was strongly positively associated with PI3K, avTOR, avLST8, and S6K1; and avTOR was strongly positively associated with S6K1. In conclusion, the activation of avTOR signaling in the liver of LRFI ducks might be ascribed to higher energy state or more active nutrient transport (amino acids), or both, than those in the liver of HRFI ducks. The results of the present study indicate that AKT and avTOR of TOR signaling might be used as candidate genes to assess molecular regulation of feed efficiency.

Expression of hepatic genes related to energy metabolism during the transition period of Holstein and F1 Holstein-Gir cows

The aim of this study was to investigate the expression of genes encoding enzymes and other factors involved with carbohydrate and lipid metabolism in the liver of 2 genetic groups of dairy cows during the transition period. We analyzed the expression of glucose-6-phosphatase (G6PC), cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C), methylmalonyl-CoA mutase (MUT), β-hydroxybutyrate dehydrogenase-2 (BDH2), acetyl-CoA carboxylase (ACC), carnitine palmitoyltransferase-2 (CPT2), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), glucose transporter-2 (SLC2A2), and the transcription factor peroxisome proliferator-activated receptor α (PPARA). Blood concentrations of glucose, nonesterified fatty acids, and β-hydroxybutyrate were also determined. Liver biopsies and blood samples were taken at d 15 prepartum and at d 6, 21, 36, 51, and 66 postpartum from Holsteins (n = 6) and F₁ Holstein-Gir (n = 6) cows. Cows were kept under the same prepartum and postpartum management conditions. The results showed that the expression of G6PC, PEPCK-C, BDH2, ACC, CPT2, HMGCR, SLC2A2, and PPARA genes did not differ between genetic groups. Except for PEPCK-C, no interaction between genetic groups and the experimental period was observed. Within both groups of cows, G6PC and PEPCK-C gene expression decreased when comparing prepartum gene expression with 21 and 36 DIM, and increased in d 51 postpartum. MUT mRNA levels differed between the 2 genetic groups and displayed a significant increase after d 36 postpartum, whereas mRNA levels of HMGCR tended to increase when comparing d 21 and 36 to d 51 postpartum. Glucose concentrations also differed between genetic groups, being significantly higher in the plasma of F₁ Holstein-Gir cows than in Holstein cows, but no differences were found within each group during the analysis period. β-Hydroxybutyrate and nonesterified fatty acid concentrations did not differ between genetic groups, but displayed increased levels from prepartum to d 6 and 21 postpartum. Our results indicated that expression in the liver of genes involved with glucose and fatty acid metabolism were similar in both groups of cows and significant differences were observed between the 2 groups in the expression of MUT, a gene involved in propionate metabolism.

Pro-Opiomelanocortin (POMC) Neurones, POMC-Derived Peptides, Melanocortin Receptors and Obesity: How Understanding of this System has Changed Over the Last Decade

Following the cloning of the melanocortin receptor and agouti protein genes, a model was developed for the central melanocortin system with respect to the regulation of energy and glucose homeostasis. This model comprised leptin regulation of melanocortin peptides and agouti-related peptide (AgRP) produced from central pro-opiomelanocortin (POMC) and AgRP neurones, respectively, as well as AgRP competitive antagonism of melanocortin peptides activating melanocortin 4 receptor (MC4R) to Gαs and the cAMP signalling pathway. In the last decade, there have been paradigm shifts in our understanding of the central melanocortin system as a result of the application of advanced new technologies, including Cre-LoxP transgenic mouse technology, pharmacogenetics and optogenetics. During this period, our understanding of G protein coupled receptor signal transduction has also dramatically changed, such that these receptors are now known to exist in the plasma membrane oscillating between various inactive and active conformational states, and the active states signal through G protein-dependent and G protein-independent pathways. The present review focuses on evidence obtained over the past decade that has changed our understanding of POMC gene expression and regulation in the central nervous system, POMC and AgRP neuronal circuitry, neuroanatomical functions of melanocortin receptors, melanocortin 3 receptor (MC3R) and MC4R, and signal transduction through MC3R and MC4R.

Effects of phenotypic residual feed intake on response to a glucose tolerance test and gene expression in the insulin signaling pathway in longissimus dorsi in beef cattle

The objectives of this study were to determine the insulinogenic response to an intravenous glucose tolerance test (GTT) and examine gene expression profiles in the insulin signaling pathway (ISP) in beef animals of differing phenotypic residual feed intake (RFI). Two experiments were conducted. In Exp. 1, a total of 39 Simmental heifers, over 2 yr (yr 1, n = 22, and yr 2, n = 17; mean initial BW = 472 kg [SD = 52.4 kg]), were offered grass silage ad libitum for 104 d. Heifers were subjected to a GTT on d 8 and 65 of the RFI measurement period in yr 1 and 2, respectively. Concentrations of plasma glucose and insulin were measured at -45, -30, -15, 0, 5, 10, 15, 20, 30, 45, 60, 90, 120, 150, and 180 min relative to glucose infusion (0 min). In Exp. 2, a total of 67 Simmental bulls, over 3 yr (yr 1, n = 20; yr 2, n = 33; and yr 3, n = 14; mean initial BW = 431 kg [SD = 63.7 kg]), were offered concentrates ad libitum for 105 d. Biopsies of LM were harvested during the RFI measurement period (yr 1, d 49 and 91; yr 2, d 52 and 92; and yr 3, d 50 and 92). The residuals of the regression of DMI on ADG, midtest metabolic BW (BW(0.75)), and the fixed effect of year, using all animals, were used to compute individual RFI coefficients. Animals were ranked on RFI and assigned to high (inefficient), medium, or low groupings by dividing them into terciles, resulting in 13 heifers and 22, 23, and 22 bulls in their respective RFI groups. In Exp. 1, data from 13 heifers from each of the high- and low-RFI groups, and in Exp. 2, data from the 15 highest and 15 lowest ranking bulls on RFI are reported. In Exp. 1, glucose and insulin response and area under the response curve for glucose and insulin were similar (P > 0.05) between high- and low-RFI heifers. In Exp. 2, no differences (P > 0.05) were found for mRNA expression of 22 genes of the ISP in muscle tissue; however, expression of the transcription factor SREBP1c tended to be positively correlated (r = 0.25, P = 0.07) with RFI. Expression of GLUT4, INPPL1, and SHC increased (P < 0.05) over time, while there was no effect of sample time for any other genes measured. Collectively, these results suggest that insulin response, sensitivity, and associated expression of genes in the ISP within muscle tissue are not contributory factors to variation in RFI. However, further examination of target genes of SREBP1c, which is involved in lipogenesis, may explain some of the biochemical processes underlying variation in phenotypic RFI.

Effect of genotype on duodenal expression of nutrient transporter genes in dairy cows

BACKGROUND

Studies have shown clear differences between dairy breeds in their feed intake and production efficiencies. The duodenum is critical in the coordination of digestion and absorption of nutrients. This study examined gene transcript abundance of important classes of nutrient transporters in the duodenum of non lactating dairy cows of different feed efficiency potential, namely Holstein-Friesian (HF), Jersey (JE) and their F1 hybrid. Duodenal epithelial tissue was collected at slaughter and stored at -80°C. Total RNA was extracted from tissue and reverse transcribed to generate cDNA. Gene expression of the following transporters, namely nucleoside; amino acid; sugar; mineral; and lipid transporters was measured using quantitative real-time RT-PCR. Data were statistically analysed using mixed models ANOVA in SAS. Orthogonal contrasts were used to test for potential heterotic effects and spearman correlation coefficients calculated to determine potential associations amongst gene expression values and production efficiency variables.

RESULTS

While there were no direct effects of genotype on expression values for any of the genes examined, there was evidence for a heterotic effect (P < 0.05) on ABCG8, in the form of increased expression in the F1 genotype compared to either of the two parent breeds. Additionally, a tendency for increased expression of the amino acid transporters, SLC3A1 (P = 0.072), SLC3A2 (P = 0.081) and SLC6A14 (P = 0.072) was also evident in the F1 genotype. A negative (P < 0.05) association was identified between the expression of the glucose transporter gene SLC5A1 and total lactational milk solids yield, corrected for body weight. Positive correlations (P < 0.05) were also observed between the expression values of genes involved in common transporter roles.

CONCLUSION

This study suggests that differences in the expression of sterol and amino acid transporters in the duodenum could contribute towards the documented differences in feed efficiency between HF, JE and their F1 hybrid. Furthermore, positive associations between the expression of genes involved in common transporter roles suggest that these may be co-regulated. The study identifies potential candidates for investigation of genetic variants regulating nutrient transport and absorption in the duodenum in dairy cows, which may be incorporated into future breeding programmes.

Short communication: expression of peptide YY, proglucagon, neuropeptide Y receptor Y2, and glucagon-like peptide-1 receptor in bovine peripheral tissues

The role of distal gut signals in control of feed intake and metabolism in cattle has received scant attention. Peptide YY (PYY) and glucagon-like peptide-1, which are secreted from enteroendocrine cells of the distal gut in monogastrics have several functions, including regulation of energy balance. However, little is known of the tissue expression of these peptides and their receptors in cattle. The aim of the current study was to characterize the tissue distribution of PYY, neuropeptide Y receptor Y2 (Y2), proglucagon (GCG), and glucagon-like peptide-1 receptor (GLP1R) in various peripheral tissues of cattle. Four male 7-wk-old dairy calves were euthanized and 16 peripheral tissues were collected. Conventional PCR and quantitative real-time PCR were performed to confirm tissue expression and quantify the transcript abundance in various tissues. The results of conventional PCR revealed that mRNA for both PYY and Y2 was detectable in the rumen, abomasum, duodenum, jejunum, ileum, and colon but not in other tissues. Quantitative real-time PCR data demonstrated that PYY mRNA was 2- to 3-fold greater in the pancreas, kidney, and heart relative to the liver. By conventional PCR, GCG mRNA was detected in the abomasum, duodenum, jejunum, ileum, and colon and GLP1R mRNA was expressed in all gut segments, pancreas, spleen, and kidney. Quantitative real-time PCR data demonstrated that, relative to transcript abundance in the liver, GCG mRNA was 4- to 40-fold higher from abomasum to colon, and GLP1R mRNA was 50- to 300-fold higher from the rumen to colon, 14-fold greater in the pancreas, 18-fold higher in the spleen, and 166-fold greater in the kidney. The tissue distribution of PYY, GCG, and their receptors observed in the current study is, in general, consistent with expression patterns in monogastrics. The predominant expression of PYY, Y2, and GCG in the gut, and the presence of GLP1R in multiple peripheral tissues suggest a role for PYY in controlling gut functions and for GLP-1 in regulating multiple physiological functions in cattle.

Cell Biology Symposium: feed efficiency: mitochondrial function to global gene expression

Understanding the cellular basis of feed efficiency (FE) is instrumental to helping poultry and livestock industries continue to provide high-quality protein for an increasingly crowded world. To understand relationships of FE and gene expression, global RNA transcription was investigated in breast muscle obtained from a male broiler line fed the same diet and individually phenotyped for FE. In these studies, RNA samples obtained from broilers that exhibited either high FE (0.65 ± 0.01) or low FE (0.46 ± 0.01) were analyzed with an Agilent 44K chicken oligoarray. A 1.3-fold cutoff in expression (30% difference between groups) resulted in 782 genes that were differentially expressed (P < 0.05) in muscle between the high- and low-FE phenotypes. Ingenuity Pathway Analysis, an online software program, was used to identify genes, gene networks, and pathways associated with the phenotypic expression of FE. The results indicate that the high-FE phenotype exhibited increased expression of genes associated with 1) signal transduction pathways, 2) anabolic activities, and 3) energy-sensing and energy coordination activities, all of which would likely be favorable to cell growth and development. In contrast, the low-FE broiler phenotype exhibited upregulation of genes 1) associated with actin-myosin filaments, cytoskeletal architecture, and muscle fibers and 2) stress-related or stress-responsive genes. Because the low-FE broiler phenotype exhibits greater oxidative stress, it would appear that the low-FE phenotype is the product of inherent gene expression that is modulated by oxidative stress. The results of these studies begin to provide a comprehensive picture of gene expression in muscle, a major organ of energy demand in an animal, associated with phenotypic expression of FE.

Tissue-specific mRNA expression patterns reveal a coordinated metabolic response associated with genetic selection for milk production in cows

The molecular mechanisms regulating the physiological adaptation of tissues important for nutrient partitioning and metabolism in lactating cows are still not completely understood. The aim of our study was to identify tissue-specific regulatory mechanisms necessary to accommodate metabolic changes associated with different genetic potential for milk performance. For this purpose, we analyzed mRNA expression of genes involved in energy metabolism of segregating F(2) beef type cows with a combined genetic dairy and beef background (Charolais × German Holstein cross, CH×GH) in contrast to purebred German Holstein (GH) dairy cows. Three groups of cows differing in milk performance were examined using quantitative real-time PCR in liver, mammary gland, and skeletal muscle. Our results describe substantial tissue-specific differences in mRNA transcription profiles between cow groups in relation to their genetic potential for milk performance and highlight genes exhibiting specific, partially yet-unknown functions in dairy and beef type cows, e.g., upregulation of PCK2 transcripts in the mammary gland and FBP2 transcripts in skeletal muscle of dairy cows. Noticeably, PCCA and PPARGC1A mRNA abundance varied significantly across experimental groups in all three tissues, pointing to potential key gene functions in the metabolic adaptation relative to divergent milk production performance. Correlations of mRNA expression levels to milk performance traits indicate that gene transcriptional processes may play a regulatory role in liver, mammary gland, and skeletal muscle to enable cows with different genetic potential for milk performance to cope with metabolic lactation-associated challenges.