Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
1.
Pharmaceuticals (Basel) ; 17(2)2024 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-38399418

RESUMO

Antimicrobial drugs and coccidiostat compounds are commonly used in poultry farming. These compounds are subsequently excreted and released into the environment via broiler litter (BL) and can re-enter the food chain as fertilizer or animal feed. Such residue in animal feed can encourage the appearance of antibiotic-resistant bacteria as well as toxicity. Most analytical methods used to identify and quantitate these drug residues are traditional, and are specific to some antimicrobials and present limitations in assessing complex matrixes like BL. The aim of this study was to develop a multi-residue analytic method for assessing 30 antimicrobial drugs and coccidiostats associated with BL. We investigated the presence and the effects of biotic stack treatment on the degradation of drug residue in BL. Liquid-liquid extraction (LLE) and solid phase extraction (SPE) were replaced by Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) clean-up steps and detected by liquid chromatography mass spectrometry (LC/MS/MS). Results show that a wide spectrum of residues were detected from 0.4 to 8.9 mg kg-1. Following lab-scale stacking treatment, tilmicosin and eight coccidiostats persisted in BL (26-100%). This research supports the need for better understanding, regulation, and management of the use of BL that might carry a high risk of residue drugs.

2.
Int J Mol Sci ; 24(23)2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-38069150

RESUMO

Pleurotus ostreatus is a white-rot fungus that can degrade lignin in a preferential manner using a variety of extracellular enzymes, including manganese and versatile peroxidases (encoded by the vp1-3 and mnp1-6 genes, respectively). This fungus also secretes a family of structurally related small secreted proteins (SSPs) encoded by the ssp1-6 genes. Using RNA sequencing (RNA-seq), we determined that ssp4 and ssp6 are the predominant members of this gene family that were expressed by P. ostreatus during the first three weeks of growth on wheat straw. Downregulation of ssp4 in a strain harboring an ssp RNAi construct (KDssp1) was then confirmed, which, along with an increase in ssp6 transcript levels, coincided with reduced lignin degradation and the downregulation of vp2 and mnp1. In contrast, we observed an increase in the expression of genes related to pectin and side-chain hemicellulose degradation, which was accompanied by an increase in extracellular pectin-degrading capacity. Genome-wide comparisons between the KDssp1 and the wild-type strains demonstrated that ssp silencing conferred accumulated changes in gene expression at the advanced cultivation stages in an adaptive rather than an inductive mode of transcriptional response. Based on co-expression networking, crucial gene modules were identified and linked to the ssp knockdown genotype at different cultivation times. Based on these data, as well as previous studies, we propose that P. ostreatus SSPs have potential roles in modulating the lignocellulolytic and pectinolytic systems, as well as a variety of fundamental biological processes related to fungal growth and development.


Assuntos
Lignina , Pleurotus , Lignina/metabolismo , Pleurotus/metabolismo , Peroxidases/genética , Peroxidases/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Pectinas/metabolismo
3.
Antibiotics (Basel) ; 12(7)2023 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-37508189

RESUMO

The use of antimicrobial drugs and coccidiostats in poultry farming is widespread, with a significant proportion of these drugs being excreted and released into the environment. The residues of such drugs in poultry litter (PL) can result in the development of antibiotic-resistant bacteria. The impact of different biotic treatments (aerobic, anaerobic, and stacking) on broiler litter (BL) before its use as animal feed has not been studied extensively, nor have the differences between antimicrobial-dependent and independent broiler farms been investigated. This study aimed to determine the resistant bacteria in BL used as ruminant feed before and after litter treatment. The results show that the most resistant bacteria before BL treatment were the Enterococcus species. This study also found that the quantity of amoxicillin-resistant Enterococcus detected in samples from antimicrobial-dependent farms was significantly higher than in those from antimicrobial-independent farms. Additionally, 14% of bacteria were multi-resistant to tetracycline, sulfafurazole, and erythromycin in antimicrobial-independent farm litters, significantly lower than those measured in antimicrobial-dependent broiler farm litter. This study highlights the importance of better understanding, regulating, managing, and using animal waste appropriately to reduce the number of antibiotic-resistant bacteria and minimize the use of antimicrobials that carry high risks for animals, humans, and the environment.

4.
Animals (Basel) ; 13(13)2023 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-37443995

RESUMO

Wheat and corn silages are widely used as ruminant feed in Israel due to their availability and cost-effectiveness. To ensure long-term preservation without compromising nutritional quality, effective methods must be employed. The inclusion of additives during harvest and ensiling can enhance efficiency and address preservation challenges. In the current study, the effects of microbial inoculum (MI) and urea on the chemical composition, amino acid profiles, aerobic stability, and in vitro digestibility of wheat and corn silages were investigated. Samples of wheat and corn were subjected to four treatments: control, MI, urea and a combination of MI + urea. The treatments were ensiled in anaerobic conditions and opened after 1, 7, 14 or 28 days. The results showed that additives improved the quality parameters of wheat and corn silages. The inclusion of MI produced the most aerobically stable silages. The inclusion of urea in silages decreased aerobic stability. Additives improved in vitro cell wall carbohydrates' digestibility in both silages and was the best when MI was combined with urea. These results imply that additives could be incorporated in silages to enhance their nutritional value, aerobic stability and digestibility. Nonetheless, increased CP content with additives was not accompanied with a parallel increase in amino acids' content in corn silage.

5.
Heliyon ; 9(3): e14581, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37009330

RESUMO

The global demand for animal-based products is rising in the face of dwindling feed resources, and yet a huge pool of agro-industrial by-products (AIBPs) are generated, underutilized, and improperly deposited to landfills leading to environmental pollution. Ruminants have a special microbiome that can bioprocess and convert human inedible fibrous material into meat and milk, which appears as a great opportunity to simultaneously reduce pollution while promoting food security. In this study, we collected 15 domestically produced AIBPs from various regions of Israel during both winter and summer seasons to examine their potential as ruminant feed alternatives. We evaluated their storability, nutritional composition, and in vitro digestibility and performed a hierarchical cluster analysis to categorize them based on their distinctive nutritional characteristics. Among the 15 AIBPs, 8 have rich essential nutrients, and minerals, and have excellent in vitro digestibility, but they have less than 6 days of storability and develop off-odours. Out of 15 AIBPs; 8 have low dry matter (DM) content, ranging from 4.7% to 30.45% while the remaining 7 AIBPs have high DM, ranging from 50.6% to 98.6%. The high crude protein (CP) category included 6 AIBPs with CP ranging from 19.7% in beer pulp to 32.1% in jojoba cake. Starch content was high in 3 AIBPs ranging from 33.7% in timorim mix to 65.2% in Irish potato culls. Considerable crude fat content was reported in 4 AIBPs, the highest being yoghurt waste with 42.8%. In terms of neutral detergent fiber (NDF), 5 AIBPs had low NDF content ranging from 0% to 14.1%; 5 AIBPs had moderate concentration ranging from 34.3% to 50.7%, and 5 AIBPs had high levels between 66.6% and 82.8%. Interestingly, 10/15 AIBPs had medium to high in vitro dry matter digestibility (IVDMD). This study, therefore, suggests that recycling AIPBs for livestock nutrition has enormous potential that is still underutilized and offers excellent ways to gain socioeconomic and environmental benefits by expanding animal feed resources and reducing feed-food competition, and landfill burden. However, additional studies are necessary to focus on affordable storage technology to prolong the storability of AIBPs and feeding trials to determine the productive performance of livestock fed an AIBPs-based diet.

6.
Animals (Basel) ; 13(8)2023 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-37106980

RESUMO

This study investigated the effect of dietary flavour supplements on the preference, feed efficiency and expression of the sweet taste receptor family 1 members 2 and 3 (T1R2 + T1R3), and sodium-glucose linked transporter 1 (SGLT1) genes in the lambs' small intestines. Eight, five-month-old, Israeli crossbred Assaf lambs were offered 16 different non-nutritive commercial flavours in rolled barley and ground corn. Capsicum and sucram were the most preferred non-aroma flavours (p = 0.020), while milky (p < 0.001) was the most preferred powder-aroma flavour. For the metabolic and relative gene expression study, eight lambs were randomly assigned to either sucram, capsicum, a mix containing sucram and capsicum at 1:1 ratio or no flavour for control in a 4 × 2 cross-over design. The total collection of urine (females only), faeces and refusals was carried out, and T1R2, T1R3 and SGLT1 relative gene expression evaluated from the proximal jejunum biopsies. Flavour had no significant effect on the feed intake (p = 0.934), but capsicum increased the average daily weight gain per metabolic body weight (p = 0.049). The T1R3 gene was expressed highest in the mix treatment (1.7; p = 0.005). Collectively, our findings indicate that flavours can be used to motivate feed acceptance and improve the weight gain in lambs.

7.
Animals (Basel) ; 13(3)2023 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-36766359

RESUMO

Tef is known as a multi-harvest crop with high production capacity and outstanding fodder quality. Hence, our overall goal is to develop tef as a new multi-harvest summer crop that can maintain high-quality feed and contribute to both field crops and the livestock industry in Israel. In this study, we aimed to evaluate the ability to preserve tef as silage. Four tef genotypes grown under well-watered (100%) and water-limited (75%) irrigation regimes were harvested at grain filling stage and ensiled with either no additives (control, CTL), or with heterofermentative inoculum (HI), molasses (MOL), and both MOL + HI. Our results showed for the first time that tef could be ensiled, although water-soluble carbohydrates (WSC) were lower than those in corn, "the perfect ensiling crop". Most of the tef silage qualitative parameters were better at water-limited irrigation. Additives HI or MOL or MOL + HI also improved silage parameters, e.g., lowered pH and ammonia nitrogen content, but increased in vitro dry matter digestibility, lactic acid and crude protein content, and lactic acid bacteria counts of tef silage. The current results imply increasing the diversity of local ruminant fodder crops, ensuring high-quality feed supply during the summer.

8.
Front Physiol ; 14: 1079638, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36760526

RESUMO

Optimal embryonic development and growth of meat-type chickens (broilers) rely on incubation conditions (oxygen, heat, and humidity), on nutrients and on energy resources within the egg. Throughout incubation and according to the embryo's energy balance, the main energy storage molecules (creatine and glycogen) are continuously utilized and synthesized, mainly in the embryonic liver, breast muscle, and the extraembryonic yolk sac (YS) tissue. During the last phase of incubation, as the embryo nears hatching, dynamic changes in energy metabolism occur. These changes may affect embryonic survival, hatchlings' uniformity, quality and post hatch performance of broilers, hence, being of great importance to poultry production. Here, we followed the dynamics of creatine and glycogen from embryonic day (E) 11 until hatch and up to chick placement at the farm. We showed that creatine is stored mainly in the breast muscle while glycogen is stored mainly in the YS tissue. Analysis of creatine synthesis genes revealed their expression in the liver, kidney, YS tissue and in the breast muscle, suggesting a full synthesis capacity in these tissues. Expression analysis of genes involved in gluconeogenesis, glycogenesis, and glycogenolysis, revealed that glycogen metabolism is most active in the liver. Nevertheless, due to the relatively large size of the breast muscle and YS tissue, their contribution to glycogen metabolism in embryos is valuable. Towards hatch, post E19, creatine levels in all tissues increased while glycogen levels dramatically decreased and reached low levels at hatch and at chick placement. This proves the utmost importance of creatine in energy supply to late-term embryos and hatchlings.

9.
PLoS One ; 16(8): e0248199, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34415905

RESUMO

The role the mammary epithelial circadian clock plays in gland development and lactation is unknown. We hypothesized that mammary epithelial clocks function to regulate mammogenesis and lactogenesis, and propose the core clock transcription factor BMAL1:CLOCK regulates genes that control mammary epithelial development and milk synthesis. Our objective was to identify transcriptional targets of BMAL1 in undifferentiated (UNDIFF) and lactogen differentiated (DIFF) mammary epithelial cells (HC11) using ChIP-seq. Ensembl gene IDs with the nearest transcriptional start site to ChIP-seq peaks were explored as potential targets, and represented 846 protein coding genes common to UNDIFF and DIFF cells and 2773 unique to DIFF samples. Genes with overlapping peaks between samples (1343) enriched cell-cell adhesion, membrane transporters and lipid metabolism categories. To functionally verify targets, an HC11 line with Bmal1 gene knocked out (BMAL1-KO) using CRISPR-CAS was created. BMAL1-KO cultures had lower cell densities over an eight-day growth curve, which was associated with increased (p<0.05) levels of reactive oxygen species and lower expression of superoxide dismutase 3 (Sod3). RT-qPCR analysis also found lower expression of the putative targets, prolactin receptor (Prlr), Ppara, and beta-casein (Csn2). Findings support our hypothesis and highlight potential importance of clock in mammary development and substrate transport.


Assuntos
Fatores de Transcrição ARNTL/fisiologia , Células Epiteliais/metabolismo , Glândulas Mamárias Animais/metabolismo , Proteínas do Leite/metabolismo , Fatores de Transcrição ARNTL/metabolismo , Anemia Falciforme , Animais , Proteína 9 Associada à CRISPR , Sistemas CRISPR-Cas , Feminino , Edição de Genes , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Glândulas Mamárias Animais/fisiologia , Camundongos
10.
Thyroid ; 28(8): 1042-1051, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29855255

RESUMO

BACKGROUND: Milk is a major source of iodine in human nutrition. Because both iodine content and the consumption of milk and dairy vary widely over time and populations, their contribution to iodine intake must be evaluated regularly. A recent national iodine survey found Israel's population to be mildly iodine deficient, possibly due to unmonitored changes in the food content of dietary iodine. Accounting for dairy iodine content can help guide efforts to prevent iodine deficiency. OBJECTIVES: This study aimed to determine the iodine concentration of dairy products typically consumed in the Israeli diet, and to estimate iodine intake from dairy products among Israeli adults. METHODS: Iodine was analyzed in 33 selected dairy products that account for 89% of the total population's dairy intake according to the "MABAT" Israeli National Health and Nutrition survey. Based on these data, the distribution of iodine intake from milk, dairy, and dairy-based foods in the adult population was calculated. RESULTS: Israeli milk is rich in iodine, with a mean concentration of 22 µg/100 g. However, due to low dairy consumption, the mean iodine intake from milk and dairy was only 34 µg/day (median 23 µg/day; range: 0-337 µg/day) or 22% of the recommended daily allowance. Self-reported intake among poor, male, and Arab subgroups was even lower. CONCLUSIONS: Because Israeli milk and dairy products are iodine rich, their contribution to the population's iodine intake would increase if they were consumed in greater amounts, particularly by high-risk groups. Dairy's potential contribution to iodine nutrition should be considered in recommendations for dairy consumption and iodine prophylaxis.


Assuntos
Laticínios/análise , Dieta , Iodo/análise , Leite/química , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Israel , Masculino , Pessoa de Meia-Idade , Inquéritos Nutricionais , Estado Nutricional , Gravidez , Adulto Jovem
11.
Am J Physiol Regul Integr Comp Physiol ; 311(6): R1125-R1134, 2016 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-27707717

RESUMO

Circadian clocks influence virtually all physiological processes, including lactation. Here, we investigate the role of the CLOCK gene in regulation of mammary epithelial cell growth and differentiation. Comparison of mammary morphology in late-pregnant wild-type and ClockΔ19 mice, showed that gland development was negatively impacted by genetic loss of a functional timing system. To understand whether these effects were due, in part, to loss of CLOCK function in the gland, the mouse mammary epithelial cell line, HC11, was transfected with short hairpin RNA that targeted Clock (shClock). Cells transfected with shClock expressed 70% less Clock mRNA than wild-type (WT) HC11 cultures, which resulted in significantly depressed levels of CLOCK protein (P < 0.05). HC11 lines carrying shClock had four-fold higher growth rates (P < 0.05), and the percentage of cells in G1 phase was significantly higher (90.1 ± 1.1% of shClock vs. 71.3 ± 3.6% of WT-HC11) following serum starvation. Quantitative-PCR (qPCR) analysis showed shClock had significant effects (P < 0.0001) on relative expression levels of Ccnd1, Wee1, and Tp63 qPCR analysis of the effect of shClock on Fasn and Cdh1 expression in undifferentiated cultures and cultures treated 96 h with dexamethasone, insulin, and prolactin (differentiated) found levels were reduced by twofold and threefold, respectively (P < 0.05), in shClock line relative to WT cultures. Abundance of CDH1 and TP63 proteins were significantly reduced in cultures transfected with shClock These data support how CLOCK plays a role in regulation of epithelial cell growth and differentiation in the mammary gland.


Assuntos
Proteínas CLOCK/metabolismo , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Células Epiteliais/citologia , Células Epiteliais/fisiologia , Glândulas Mamárias Animais/fisiologia , Animais , Células Cultivadas , Ritmo Circadiano/fisiologia , Feminino , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Masculino , Glândulas Mamárias Animais/citologia , Camundongos , Camundongos Endogâmicos C57BL
12.
Environ Microbiol ; 16(1): 265-77, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24119015

RESUMO

Lignin biodegradation by white-rot fungi is pivotal to the earth's carbon cycle. Manganese peroxidases (MnPs), the most common extracellular ligninolytic peroxidases produced by white-rot fungi, are considered key in ligninolysis. Pleurotus ostreatus, the oyster mushroom, is a preferential lignin degrader occupying niches rich in lignocellulose such as decaying trees. Here, we provide direct, genetically based proof for the functional significance of MnP to P. ostreatus ligninolytic capacity under conditions mimicking its natural habitat. When grown on a natural lignocellulosic substrate of cotton stalks under solid-state culture conditions, gene and isoenzyme expression profiles of its short MnP and versatile peroxidase (VP)-encoding gene family revealed that mnp2 was predominately expressed. mnp2, encoding the versatile short MnP isoenzyme 2 was disrupted. Inactivation of mnp2 resulted in three interrelated phenotypes, relative to the wild-type strain: (i) reduction of 14% and 36% in lignin mineralization of stalks non-amended and amended with Mn(2+), respectively; (ii) marked reduction of the bioconverted lignocellulose sensitivity to subsequent bacterial hydrolyses; and (iii) decrease in fungal respiration rate. These results may serve as the basis to clarify the roles of the various types of fungal MnPs and VPs in their contribution to white-rot decay of wood and lignocellulose in various ecosystems.


Assuntos
Proteínas Fúngicas/genética , Lignina/metabolismo , Peroxidases/genética , Pleurotus/enzimologia , Madeira/microbiologia , Sequência de Aminoácidos , Proteínas Fúngicas/metabolismo , Inativação Gênica , Dados de Sequência Molecular , Peroxidases/metabolismo , Pleurotus/genética , Pleurotus/metabolismo , Madeira/metabolismo
13.
PLoS One ; 7(12): e52446, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23285046

RESUMO

The versatile-peroxidase (VP) encoded by mnp4 is one of the nine members of the manganese-peroxidase (MnP) gene family that constitutes part of the ligninolytic system of the white-rot basidiomycete Pleurotus ostreatus (oyster mushroom). VP enzymes exhibit dual activity on a wide range of substrates. As Mn(2+) supplement to P. ostreatus cultures results in enhanced degradation of recalcitrant compounds and lignin, we examined the effect of Mn(2+) on the expression profile of the MnP gene family. In P. ostreatus (monokaryon PC9), mnp4 was found to be the predominantly expressed mnp in Mn(2+)-deficient media, whereas strongly repressed (to approximately 1%) in Mn(2+)-supplemented media. Accordingly, in-vitro Mn(2+)-independent activity was found to be negligible. We tested whether release of mnp4 from Mn(2+) repression alters the activity of the ligninolytic system. A transformant over-expressing mnp4 (designated OEmnp4) under the control of the ß-tubulin promoter was produced. Now, despite the presence of Mn(2+) in the medium, OEmnp4 produced mnp4 transcript as well as VP activity as early as 4 days after inoculation. The level of expression was constant throughout 10 days of incubation (about 0.4-fold relative to ß-tubulin) and the activity was comparable to the typical activity of PC9 in Mn(2+)-deficient media. In-vivo decolorization of the azo dyes Orange II, Reactive Black 5, and Amaranth by OEmnp4 preceded that of PC9. OEmnp4 and PC9 were grown for 2 weeks under solid-state fermentation conditions on cotton stalks as a lignocellulosic substrate. [(14)C]-lignin mineralization, in-vitro dry matter digestibility, and neutral detergent fiber digestibility were found to be significantly higher (about 25%) in OEmnp4-fermented substrate, relative to PC9. We conclude that releasing Mn(2+) suppression of VP4 by over-expression of the mnp4 gene in P. ostreatus improved its ligninolytic functionality.


Assuntos
Manganês/farmacologia , Peroxidases/metabolismo , Pleurotus/enzimologia , Compostos Azo/metabolismo , Biodegradação Ambiental/efeitos dos fármacos , Isótopos de Carbono , Corantes/metabolismo , Fermentação/efeitos dos fármacos , Fermentação/genética , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Genes Fúngicos/genética , Engenharia Genética , Humanos , Lignina/metabolismo , Peroxidases/genética , Pleurotus/efeitos dos fármacos , Pleurotus/genética , Especificidade por Substrato/efeitos dos fármacos , Fatores de Tempo
14.
J Nutr ; 139(6): 1118-27, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19403714

RESUMO

The high energetic demands and metabolism of amino acids (AA) within the lactating mammary gland have been ascribed to the requirements for milk component synthesis and tissue maintenance. Our objective in this work was to assess rates of protein synthesis from several AA so that the energetic costs of tissue maintenance could be better reflected. Lactating goats (n = 4) were given staggered infusions of 5 labeled forms of phenylalanine (Phe) initiated at 30, 12, 9, 6, and 3 h before goats were killed. [5-(13)CH(3)] Methionine (Met), [1-(13)C] leucine, and [1-(13)C] valine were also infused for 30 h, during which time, the glands were milked hourly and arteriovenous flux measurements were performed the last 6 h. A dynamic, compartmental model capable of simulating fluxes of AA through extracellular and intracellular free, slow and fast turnover tissue-bound, and milk protein pools was developed and fitted to the observed data. The udder removed 81% of the Phe present in plasma using 31% for milk protein synthesis and releasing 66% back into plasma. Transamination accounted for 40% of Phe flux in the mammary and transmethylation accounted for a portion of mammary Met flux. Mammary tissue protein synthesis was >300% the value of milk protein synthesis with fractional protein synthesis rates >130%/d. Assuming 4 mol of ATP/mol of peptide bond formed, we estimate that approximately 50% of ATP generated by the lactating mammary glands is used for synthesis of tissue (nonmilk) protein.


Assuntos
Aminoácidos/metabolismo , Metabolismo Energético/fisiologia , Cabras/metabolismo , Lactação/metabolismo , Glândulas Mamárias Animais/metabolismo , Proteínas do Leite/metabolismo , Trifosfato de Adenosina , Animais , Feminino , Cinética
15.
Int J Endocrinol ; 2009: 427260, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-20049155

RESUMO

Leptin, like estrogen, is one of the endo/paracrine factors, which are synthesized in and secreted from mature adipocytes. The roles of the mammary fat pad and mammary adipocytes in the initiation of lactation are not clear. In this study, we showed that combination of prolactin, leptin and estrogen elevated the expression of the milk protein beta-lactoglobulin. We also showed that after prolactin stimulate the secretion of leptin from the mammary fat, leptin upregulated the expression of estrogen receptor alpha in the mammary epithelial cells. Also, prolactin affected aromatase mRNA expression in the bovine mammary fat and we demonstrated that leptin and prolactin can affect cholesterol secretion from explants in culture to the medium. Therefore, we suggest that prolactin initiates estrogen expression (as represented by aromatase mRNA) in the mammary fat pad, whereas leptin stimulates estrogen receptor alpha expression in the mammary epithelial cells. We hypothesize that leptin and estrogen, secreted from the mammary fat regulate lactation after stimulation of prolactin.

16.
Br J Nutr ; 89(5): 573-80, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12720577

RESUMO

The purpose of the present study was to determine the effect of abomasal casein infusion on glucose uptake and abundance of the Na+/glucose co-transporter (SGLT1) 1 in the ovine small intestine. Lambs (body weight 35 (sem 1.0) kg) were surgically fitted with abomasal infusion catheters and were fed diets containing equal portions of wheat hay and cracked maize. Lambs were infused with either 500 g water/d or with 500 g water containing 35 g casein/d. The infusion period lasted 10 d, after which lambs were killed, exsanguinated and eviscerated. Brush border membrane vesicles (BBMV) were prepared using mucosa from different small intestinal regions. Intake and total tract digestibility of nutrients were similar between treatments and averaged 1134, 1142 and 486 g/d and 67, 70, and 94 % for DM, organic matter and non-structural carbohydrates respectively. Crude protein (Nx6.25) digestibility was 15 % greater in the casein-infused than control lambs. Glucose uptake to BBMV ranged from 101 to 337 pmol/mg protein per s along the small intestine and was greatest in the mid-section of the small intestine. In the mid-jejunum, glucose uptake was greater (P<0.07) in lambs infused with casein and averaged 120 pmol/mg protein per s compared with 68 pmol/mg protein per s in the control group. SGLT1 affinity was similar between treatments and averaged 104 microm in the different segments of the small intestine of lambs. However, lambs infused with casein exhibited similar values along the small intestine and affinity averaged 106 microm, while in the control group a greater affinity (85 microm) was measured in the mid-jejunum. SGLT1 protein abundance was correlated with glucose uptake in the BBMV in the casein-treated lambs, but not in the control group. These results suggest that glucose uptake along the small intestine of lambs is influenced by casein or its derivatives in the small intestine via SGLT1 affinity and activity at the brush border membrane, and that SGLT1 activity may be regulated by post-translational events affected by amino acids and peptides.


Assuntos
Caseínas/administração & dosagem , Digestão , Intestino Delgado/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas de Transporte de Monossacarídeos/metabolismo , Ovinos/metabolismo , Abomaso , Animais , Glucose/metabolismo , Jejuno/metabolismo , Microvilosidades/metabolismo , Transportador 1 de Glucose-Sódio , Amido/metabolismo
17.
Life Sci ; 70(23): 2707-19, 2002 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-12269377

RESUMO

Mammary involution is triggered by local stimuli, but the precise mechanism has not been defined. Milk stasis accumulate local signals, which makes the tight junctions (TJ) leaky. The aim of the study was to check the hypothesis that casein hydrolyzates (CNH) compromise TJ integrity and dry up milk secretion. A single dose of CNH transiently (12 to 24 h) compromised TJ integrity in the treatedudder. This was associated by a transient (12 to 96 h) decline in milk secretion. No such changes were recorded in the contralateral gland that served as a control. Four repeated doses of CNH after each milking caused drastic changes in mammary secretion and composition, which were associated with irreversible cessation of milk secretion within 96 h. No such changes were recorded in goats treated with de-phosphorylated casein (control). We conclude that CNH are the milk-borne factors that cause the disruption of TJ integrity and induction of involution, and that the serine-Ps in the CNHs are essential for the excretion of biological activity.


Assuntos
Caseínas/farmacologia , Lactação/efeitos dos fármacos , Glândulas Mamárias Animais/efeitos dos fármacos , Leite/metabolismo , Fragmentos de Peptídeos/farmacologia , Junções Íntimas/efeitos dos fármacos , Animais , Cálcio/metabolismo , Células Epiteliais , Epitélio/efeitos dos fármacos , Feminino , Cabras , Lactação/fisiologia , Glândulas Mamárias Animais/citologia , Gravidez
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA