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ABSTRACT: Two experiments were conducted to determine the impact of Ca, phytase, sampling time, and age on the digestibility (AID) of Ca and P and the expression of their transporters. Cobb 500 male chicks (N = 600) were used in each experiment and allocated to cages with 10 (Exp 1, 8–11 d) or 5 (Exp 2, 21–24 d) birds/cage and 10 (Exp 1) or 20 (Exp 2) reps/treatment. Treatments were a 2 × 3 factorial arrangement, with low (LOW) or standard (STD) Ca level and 3 phytase (PHY) levels (0, 300, or 3,000 FYT/kg). Ileal digesta were collected at 8, 12, 24, 48, and 72 h, and jejunum tissues at 12, 48, and 72 h after the start of feeding experimental diets. In Exp 1, there was no effect of Ca or phytase on the AID of Ca at 8, 12, or 24 h. Phytase increased the AID of P (P < 0.05) at all time points, and the magnitude was influenced by Ca. At 12 h, the mRNA level of P (NaPi-IIb) and Ca (CaSR) transporters was greatest in the LOW diets without phytase (Ca × PHY, P ≤ 0.06). In Exp 2, the STD diet decreased the AID of Ca and P (P < 0.05) at 8, 24, 48, or 72 h. Phytase increased the AID of Ca (P < 0.05) at 8, 12, and 24 h, and decreased the AID of Ca (quadratic, P < 0.05) in the STD diet (48 h). The AID of P (P < 0.05) increased with phytase at all sampling times. At 48 h, 3,000 FYT/kg decreased (P < 0.05) mRNA expression of NaPi-IIb and Ca transporter ATP2B1 in the STD diet (Ca × PHY, P < 0.05). In conclusion, to avoid adaptation of broilers to Ca and P deficiencies, the optimal time on experimental diets is ≤ 48 h for young broilers and ≤ 24 h in older birds due to up- or down-regulation of Ca and P transporters in response to dietary Ca, P, and phytase.

ABSTRACT: The present study was undertaken to evaluate the efficacy of 2 graded levels (0.03 and 0.05% of diet) of a monoglyceride blend containing butyric, caprylic, and capric acids in broilers’ diet for optimizing gut structure and animal growth performance. For this purpose, a total of 210, one-day-old male Ross 308 broiler chicks were randomly allocated to 3 experimental treatments using 7 replicates each and 10 birds/replicate. The treatment groups involved supplementation of blend of short and medium chain fatty acids at the level of 0, 0.03, and 0.05% of the diet for 42 d. The incorporation of mixes of monoglycerides into broilers’ diet linearly improved BWG between d 0 and 21 (P = 0.034). At the end of trial, however, no significant changes were observed in performance indexes (BWG, FI, FCR). Jejunal morphometric parameters (villus height, crypt depth, and their ratio) remained unaltered with the monoglyceride supplementation on d 21. The results further showed that monoglycerides supplementation increased the goblet cell counts along the jejunal villi (P = 0.034) and crypt regions (P = 0.022), as well as it effectively modulated the mRNA abundances of tight junction protein (ZO-1, P = 0.033) and nutrient transporters (SGLT, PePT1; P = 0.005, 0.023, respectively) in the jejunum. Moreover, the downregulation in mRNA abundance of TNFα (P = 0.030) was observed with the monoglyceride supplementation. The SCFAs analysis of cecal contents showed no notable differences with monoglyceride blend supplementation when compared to the unsupplemented group. Collectively, high goblet cell numbers in the jejunum along with downregulation of the mRNA abundances of pro-inflammatory cytokines, upregulation of tight junction proteins, and nutrient transporters showed favorable responses of low doses of monoglycerides blend in broiler feeding. Further studies should be conducted in different rearing conditions to examine the effectiveness of such low levels of a monoglyceride blend in the modulation of gut structure, its functionality and animal performance.

Plasma membrane transporters play pivotal roles in the import of nutrients, including sugars, amino acids, nucleobases, carboxylic acids, and metal ions, that surround fungal cells. The selective removal of these transporters by endocytosis is one of the most important regulatory mechanisms that ensures a rapid adaptation of cells to the changing environment (e.g., nutrient fluctuations or different stresses). At the heart of this mechanism lies a network of proteins that includes the arrestin‐related trafficking adaptors (ARTs) which link the ubiquitin ligase Rsp5 to nutrient transporters and endocytic factors. Transporter conformational changes, as well as dynamic interactions between its cytosolic termini/loops and with lipids of the plasma membrane, are also critical during the endocytic process. Here, we review the current knowledge and recent findings on the molecular mechanisms involved in nutrient transporter endocytosis, both in the budding yeast Saccharomyces cerevisiae and in some species of the filamentous fungus Aspergillus. We elaborate on the physiological importance of tightly regulated endocytosis for cellular fitness under dynamic conditions found in nature and highlight how further understanding and engineering of this process is essential to maximize titer, rate and yield (TRY)-values of engineered cell factories in industrial biotechnological processes.

The small intestine is an important digestive organ and plays a vital role in the life of a pig. We tested the hypothesis that the length of the small intestine is related to growth performance and intestinal functions of piglets. A total of 60 piglets (Duroc × Landrace × Yorkshire), weaned at day 21, were fed an identical diet during a 28-day trial. At the end of the study, all piglets were sacrificed, dissected and grouped according to small intestine lengths (SILs), either short small intestine (SSI), middle small intestine (MSI) or long small intestine (LSI), respectively. Positive relationships between SIL and BW, average daily gain (ADG), average daily feed intake (ADFI) and gain-to-feed ratios (G : F) were observed. Final BW, ADG, ADFI and G : F significantly increased (P < 0.05) in MSI and LSI piglets compared with SSI piglets. Short small intestine and MSI had greater jejunal mucosa sucrase and alkaline phosphatase activities (P < 0.05) than LSI piglets. The mRNA level of solute carrier family 2 member 2 (Slc2a2) in the jejunal mucosa of SSI piglets was the greatest. The MSI piglets had a greater (P < 0.05) ileal villus height than other piglets and greater (P < 0.05) villus height-to-crypt depth ratios than LSI piglets. However, the LSI piglets had a greater (P < 0.05) ileal crypt depth than SSI piglets. No significant differences in duodenal, jejunal, caecal and colonic morphologies were detected among the groups. Moreover, luminal acetate, propionate, butyrate and total short-chain fatty acid contents were greater (P < 0.05) in SSI and MSI piglets than those in LSI piglets. In addition, there was greater serum glucose concentration in MSI piglets than other piglets. Serum albumin concentration in SSI piglets was the lowest. In conclusion, these results indicate that SIL was significantly positively associated with growth performance, and in terms of intestinal morphology and mucosal digestive enzyme activity, the piglets with a medium length of small intestine have better digestion and absorption properties.

The effects of egg storage duration (ESD) and brooding temperature (BT) on BW, intestine development and nutrient transporters of broiler chicks were investigated. A total of 396 chicks obtained from eggs stored at 18°C for 3 days (ESD3-18°C) or at 14°C for 14 days (ESD14-14°C) before incubation were exposed to three BTs. Temperatures were initially set at 32°C, 34°C and 30°C for control (BT-Cont), high (BT-High) and low (BT-Low) BTs, respectively. Brooding temperatures were decreased by 2°C each at days 2, 7, 14 and 21. Body weight was measured at the day of hatch, 2, 7, 14, 21, 28 and 42. Cloacal temperatures of broilers were recorded from 1 to 14 days. Intestinal morphology and gene expression levels of H+-dependent peptide transporter (PepT1) and Na-dependent glucose (SGLT1) were evaluated on the day of hatch and 14. Cloacal temperatures of chicks were affected by BTs from days 1 to 8, being the lowest for BT-Low chicks. BT-High resulted in the heaviest BWs at 7 days, especially for ESD14-14°C chicks. This result was consistent with longer villus and larger villus area of ESD14-14°C chicks at BT-High conditions. From 14 days to slaughter age, BT had no effect on broiler weight. ESD3-18°C chicks were heavier than ESD14-14°C chicks up to 28 days. The PepT1 and SGLT1 expression levels were significantly higher in ESD3-18°C chicks than ESD14-14°C on the day of hatch. There was significant egg storage by BT interaction for PepT1 and SGLT1 transporters at day 14. ESD14-14°C chicks had significantly higher expression of PepT1 and SGLT1 at BT-Low than those at BT-Cont. ESD14-14°C chicks upregulated PepT1 gene expression 1.15 and 1.57-fold at BT-High and BT-Low, respectively, compared with BT-Cont, whereas PepT1 expression was downregulated 0.67 and 0.62-fold in ESD3-18°C chicks at BT-High and BT-Low. These results indicated that pre-incubation egg storage conditions and BTs affected intestine morphology and PepT1 and SGLT1 nutrient transporters expression in broiler chicks.

In recent years, researchers have given emphasis on the differences in physiological parameters between early and late hatched chicks within a hatch window. Considering the importance of intestine development in newly hatched chicks, however, changes in gene expression of nutrient transporters in the jejunum of early hatched chicks within a hatch window have not been studied yet. This study was conducted to determine the effects of egg storage duration before incubation and hatch window on intestinal development and expression of PepT1 (H+-dependent peptide transporter) and SGLT1 (sodium–glucose co-transporter) genes in the jejunum of early hatched broiler chicks within a 30 h of hatch window. A total of 1218 eggs obtained from 38-week-old Ross 308 broiler breeder flocks were stored for 3 (ES3) or 14 days (ES14) and incubated at the same conditions. Eggs were checked between 475 and 480 h of incubation and 40 chicks from each egg storage duration were weighed; chick length and rectal temperature were measured. The chicks were sampled to evaluate morphological parameters and PepT1 and SGLT1 expression. The remaining chicks that hatched between 475 and 480 h were placed back in the incubator and the same measurements were conducted with those chicks at the end of hatch window at 510 h of incubation. Chick length, chick dry matter content, rectal temperature and weight of small intestine segments increased, whereas chick weight decreased during the hatch window. The increase in the jejunum length and villus width and area during the hatch window were higher for ES3 than ES14 chicks. PepT1 expression was higher for ES3 chicks compared with ES14. There was a 10.2 and 17.6-fold increase in PepT1 and SGLT1 expression of ES3 chicks at the end of hatch window, whereas it was only 2.3 and 3.3-fold, respectively, for ES14 chicks. These results suggested that egg storage duration affected development of early hatched chicks during 30 h of hatch window. It can be concluded that the ES14 chicks would be less efficiently adapted to absorption process for carbohydrates and protein than those from ES3 at the end of the hatch window.

Background: Birthweight is a critical predictor of congenital heart disease (CHD) surgical outcomes. Hypoplastic left heart syndrome (HLHS) is cyanotic CHD with known fetal growth restriction and placental abnormalities. Transposition of the great arteries (TGA) is cyanotic CHD with normal fetal growth. Comparison of the placenta in these diagnoses may provide insights on the fetal growth abnormality of CHD., Methods: Clinical data and placental histology from placentas associated with Transposition of the Great Arteries (TGA) were analyzed for gross pathology, morphology, maturity and vascularity and compared to both control and previously analyzed HLHS placentas [1]. RNA was isolated from HLHS, TGA and control placentas and sequenced by Illumina HiSeq.Transcriptome analysis was performed using AltAnalyze. Immunohistochemistry was utilized to assess placental nutrient transporter expression in all three groups., Results: Placental weight was reduced in TGA cases, and demonstrated reduced villous vasculature, immature terminal villi in the parenchyma compared to controls and reflected our previous data from HLHS placentas. However, birth weight was not reduced in TGA cases compared to controls in contrast to the HLHS cohort and birthweight:placental weight ratio was significantly increased in TGA cases but not HLHS compared to control. Transcriptomic and histologic analysis demonstrates reduced cell activity and nutrient transport capability in HLHS but not TGA placentas which appear to increase/maintain these mechanisms., Conclusions: Despite common vascular disturbances in placentas from HLHAs and TGA, these do not account for the disparities in birthweights frequently seen between these CHD subtypes, in contrast our transcriptomic and histologic analyses reveal differentially regulated mechanisms between the subtypes that may explain these disparities., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Heat stress has a serious impact on nutrient digestion and absorption in broiler chickens. This study aimed to investigate the effects of chronic heat stress (CHS) on the mRNA expression of digestive enzymes and nutrient transporter genes in thermally manipulated (TM) broiler chickens. The evaluated genes encompassed pancreatic lipase, trypsin, amylase, maltase, and alkaline phosphatase as well as certain glucose transporter (GLUT2, SGLT1), amino acid transporter (y+LAT1, CAT1), and fatty acid transporter (FABP1, CD36) genes in the jejunal mucosa. Thermal manipulation was carried out at 39°C and 65% relative humidity for 18 h daily from embryonic days (ED) 10-18, while CHS was induced by raising the temperature to 35°C for 7 D throughout post-hatch days 28 to 35. After 0, 1, 3, 5, and 7 D of CHS, the pancreas and jejunal mucosa were collected from the control and TM groups to evaluate the mRNA expression by relative-quantitative real-time qRT-qPCR. Thermal manipulation significantly decreased the cloacal temperature (Tc) and the hatchling weight, and improved weight gain in broilers during post-hatch life and CHS. In addition, TM decreased the mortality rate during CHS. During CHS, the mRNA expression levels of SGLT1, GLUT2, FABP1, and trypsin were significantly decreased after 1 D in control chickens, and this lower expression persisted until day 7, after which it further decreased. In contrast, in TM chickens, SGLT1, GLUT2, and FABP1 expression decreased after 3, 5, and 7 D of CHS, respectively, while no significant change in trypsin expression was observed throughout the CHS period. Moreover, it was found that TM significantly modulated the mRNA expression dynamics of CD36, alkaline phosphatase, y+LAT1, CAT1, lipase, amylase, and maltase during CHS exposure. The findings of this study suggest that, in broiler chickens, TM has a long-lasting impact on nutrient digestion and absorption capabilities as well as Tc, mortality rates, and BW during CHS., (© 2019 Poultry Science Association Inc.)

Little is known about the effect of low-protein (LP) diets on intestinal barrier function and permeability. In the first part of this study, starting on day 9 of age, the growth performance of the birds fed 3 experimental diets in each phase of feeding (G/F: grower/finisher) was investigated. Three experimental diets were as follows: LP (170/150 g/kg CP) fortified with essential amino acids (EAA), standard protein (SP), (202/190 g/kg), and high protein (HP) (220/210 g/kg). LP and SP diets contained a similar level of EAA concentration, while the HP diet contained 10% above the Ross 308 specifications. Each diet was replicated 6 times (10 male birds per replicate). The second part investigated intestinal permeability (IP) and function on additional 72 birds. On days 14, 16, and 20, a total of 36 birds (12 birds per diet) were injected with dexamethasone (DEX) to induce leaky gut. Birds fed LP diets had lower body weight gain (BWG) and higher feed conversion ratio (FCR) compared with SP and HP diets in both grower and finisher phases of feeding. For the challenge part, DEX increased the FCR independent of diets. Diet and DEX interacted for BWG, whereby the effect of diets was only evident in sham-injected birds. Birds fed LP had a higher fluorescein isothiocyanate dextran (FITC-d) concentration indicating a more permeable intestine compared to HP, but similar to SP. DEX increased FITC-d concentration in all dietary treatments. Birds fed LP had less ileal zonula occludens-2 (ZO-2) expression in comparison with SP, but not HP. DEX increased the expression of Claudin3 and ZO-2 and reduced Claudin1 (P < 0.05) and junctional adhesion molecule 2 in the ileum. Expression of ileal Na+-dependent glucose transporter 1 (SGLT1) was upregulated in LP fed group. It is concluded that compared with SP, IP can be maintained in LP by supplementing EAA. However, when compared with HP, feeding birds with LP may lead to a higher IP. DEX had a profound independent effect on intestinal barrier function., (© 2018 Poultry Science Association Inc.)

Within the last 60 yr genetics of broilers have changed to produce rapid growing birds that achieve market weight in 6 wk or less. To investigate the differences in factors that play a role in nutrient processing and uptake between modern fast growing (Ross) and slow growing broilers not selected for growth (ACRBC), a study was carried comparing the expression of 13 genes that encode amino acid transporters (ASCT1, ATBo,+, BoAT, bo, +AT, CAT1, CAT2, EAAT3, γ+LAT1, and LAT1) and sugar transporters (GLUT2 and GLUT5), as well as aminopeptidase (APN) and the di- and tri-peptide transporter PepT1. The growth rate of Ross birds was approximately 4 times greater than that of ACRBCs, and the feed conversion ratio (FCR) was greater in ACRBCs at all-time points measured. Gene expression in the duodenum, jejunum, and ileum was measured at 1, 3, 5, 10, and 14 d post hatch (PH). The expression of genes that encode proteins (particularly ASCT1, ATBo, +, and BoAT) located at the brush border of the gut epithelium was generally higher in ACRBCs especially at earlier time points. The expression of genes that encode proteins located at the basolateral surface of the gut epithelium was less affected. The expression of GLUT2 and GLUT5 was significantly decreased in ACRBCs at most time points and gut segments. Based on the present data we conclude that expression of brush border and sugar transporters in the small intestine can be correlated with growth. Presented increases the identification of the factors that influence growth and will assist future studies of the function of these molecules., (Published by Oxford University Press on behalf of Poultry Science Association 2019.)

Coccidiosis in chickens is caused by infection of gut epithelial cells with protozoan parasites of the genus Eimeria This disease causes losses to the poultry industry since infected birds fail to gain weight as rapidly as non-infected birds and efficiency of feed conversion is compromised. For the present study the effect of Eimeria on expression of components of amino acid and sugar uptake mechanisms was determined. Broiler chicks were infected with Eimeria maxima, which infects the jejunum; Eimeria acervulina, which infects the duodenum; or Eimeria tenella, which infects the ceca. Sections of the jejunum, duodenum, and ceca (depending on species of Eimeria) were taken at several time points between d zero and 14 post infection (PI) for mRNA expression analysis. Genes examined included one digestive enzyme, 7 peptide and amino acid transporters located on the brush border, 8 transporters located at the basolateral surface of the gut epithelium, and 5 sugar transporters. All 3 Eimeria species examined caused decrease in expression of brush border transporters particularly at d 5 to 7 PI, which corresponds to the time when pathology is greatest. The same pattern was seen in expression of sugar transporters. However, the expression of basolateral transporters differed among species. Eimeria tenella infection resulted in decreased expression of all basolateral transporters, while E. maxima infection caused increased expression of 2 genes and slight decrease in expression of the remaining 5 genes. Infection with E. acervulina resulted in increased expression at the height of infection of all but one basolateral transporter. In conclusion, Eimeria infection causes a general decrease in gene expression of sugar transporter and brush border AATs at the height of infection. However the expression of basolateral transporters is increased in E. maxima and E. acervulina infected birds. It is possible that decreased expression of brush border transporters in combination with increased expression of basolateral transporters leads to decrease of nutrients available for the parasite, thus limiting parasite reproduction., (Published by Oxford University Press on behalf of Poultry Science Association 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

Methionine is the first limiting amino acid in all poultry corn-soybean based diets. The objective of this study was to determine the effect of supplementation of L-methionine (L-Met), DL-methionine (DL-Met), and the methionine analogue, DL-2-hydroxy-4-(methylthio) butanoic acid (DL-HMTBA), on biochemical and physiological parameters of broiler chickens. Male Cobb-500 broilers were fed from day of hatch (d 0) to d 35 posthatch using a basal diet deficient in methionine plus cysteine (Met + Cys) (control), or the basal diet supplemented with 0.22% DL-Met, 0.22% L-Met, or 0.31% DL-HMTBA to meet the Met + Cys requirements. Tissue (liver, duodenum, jejunum, and ileum) and blood samples were collected at various ages, from d 0 to d 35. Performance of the birds, blood parameters (e.g., acute phase proteins, white blood cell counts), mRNA expression of intestinal nutrient transporters and DNA methylation properties of liver tissues were examined. Both body weight and feed efficiency were improved in methionine supplemented groups compared to the control group. No significant differences were observed among DL-Met, L-Met, and DL-HMTBA for growth performance parameters. L-Met and DL-Met supplementation decreased the acute phase protein, serum amyloid A, while DL-HMTBA had no effect. Methionine supplementation had no effect on white blood cell differentiation count, hepatic total DNA methylation, or DNA methyltransferase activity. L-Met and DL-Met, but not DL-HMTBA, supplementation, resulted in enhanced expression of the ATB 0,+ and B 0 AT transporters in various small intestinal segments. All methionine sources increased expression of MCT1 in the jejunum. In conclusion, methionine supplementation improved growth performance of male broilers. Methionine supplementation was also associated with changes in intestinal nutrient transporter gene expression in certain segments and ages, suggesting that intestinal amino acid absorptive function can be regulated by the source of amino acid and effects are complex and dynamic., (© 2016 Poultry Science Association Inc.)

Nutrients are absorbed in the small intestine through a variety of transporter proteins, which have not been as well characterized in turkeys as in chickens. The objective of this study was to profile the mRNA expression of amino acid and monosaccharide transporters in the small intestine of male and female turkeys. Jejunum was collected during embryonic development (embryonic d 21 and 24, and d of hatch (DOH)) and duodenum, jejunum, and ileum were collected in a separate experiment during posthatch development (DOH, d 7, 14, 21, and 28). Real-time PCR was used to determine expression of aminopeptidase N (APN), one peptide (PepT1), 6 amino acid (ASCT1, b(o,+)AT, CAT1, EAAT3, LAT1, y(+)LAT2) and 3 monosaccharide (GLUT2, GLUT5, SGLT1) transporters. Data were analyzed by ANOVA using JMP Pro 11.0. APN, b(o,+)AT, PepT1, y(+)LAT2, GLUT5, and SGLT1 showed increased expression from embryonic d 21 and 24 to DOH. During posthatch, all genes except GLUT2 and SGLT1 were expressed greater in females than males. GLUT2 was expressed the same in males as females and SGLT1 was expressed greater in males than females. All basolateral membrane transporters were expressed greater during early development then decreased with age, while the brush border membrane transporters EAAT3, GLUT5, and SGLT1 showed increased expression later in development. Because turkeys showed high-level expression of the anionic amino acid transporter EAAT3, a direct comparison of tissue-specific expression of EAAT3 between chicken and turkey was conducted. The anionic amino acid transporter EAAT3 showed 6-fold greater expression in the ileum of turkeys at d 14 compared to chickens. This new knowledge can be used not only to better formulate turkey diets to accommodate increased glutamate transport, but also to optimize nutrition for both sexes., (© 2015 Poultry Science Association Inc.)