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PubMed2004

Residual mesorectal lymph node involvement following neoadjuvant combined-modality therapy: rationale for radical resection?

BACKGROUND: In order to evaluate the impact of preoperative radiation and chemotherapy (combined modality therapy, or CMT) on primary rectal cancer and mesorectal lymph nodes (MLNs), middle and lower third rectal cancers were resected with total mesorectal excision (TME) and assessed for frequency of MLN retrieval and residual MLN involvement. METHODS: Between 1990 and 2001, 187 consecutive patients underwent abdominoperineal resection (APR) or low anterior resection (LAR) for locally advanced (endorectal ultrasound [ERUS] stage, T3-4) mid and distal rectal cancer following preoperative CMT. Sphincter preservation was possible in 150 patients (80%). The mean number of retrieved MLNs was 10.6. Pre-CMT ERUS stage was compared with final pathologic stage. RESULTS: Comparison of pre-CMT ERUS stage with pathologic stage revealed a decrease in T stage in 93 patients (49%), as well as a decrease in the percentage of individuals with positive MLNs, from 54% to 27% (P <.0001). The overall incidence of positive MLN involvement was 27%, and incidence paralleled pathologic T stage (pT): pT0 = 7%, pT1 = 8%, pT2 = 22%, pT3 = 37%, and pT4 = 67%. CONCLUSIONS: Following preoperative CMT, the incidence of residual MLN involvement remains significant and parallels increasing pT stage. Therefore, the standard of care for locally advanced distal rectal cancer should continue to include formal rectal resection (TME).

Adult↗
PubMed2006

Retroperitoneal and lateral pelvic lymphadenectomy mapped by lymphoscintigraphy and blue dye for rectal adenocarcinoma staging: preliminary results.

BACKGROUND: Total mesorectal excision (TME) is the standard surgical choice for rectal adenocarcinoma. Better prognostic results, achieved with a retroperitoneal and lateral pelvic lymphadenectomy (RLPL), have questioned that TME might not be satisfactory for adequate patient staging, affecting therapeutic definitions. The aims of the ongoing study are to define the accuracy of dye and probe search in the detection of metastatic retroperitoneal and lateral pelvic nodes (RLPN) resected with RLPL, and to evaluate the metastasis frequency in these nodes and its eventual upstaging impact. METHODS: Thirty rectal adenocarcinoma patients were submitted to RLPL, with RLPN mapping using technetium (Tc 99 m) and patent blue, having nodes examined histopathologically and immunohistochemically. RESULTS: Eight hundred and two nodes were analyzed, mean of 26.7 per patient; RLPL was responsible for 41% (330) of the examined nodes, mean of 11 per patient. Metastatic RLPN have occurred in 20% of the patients; the RLPN were metastatic in only 6.7% of the patients; RLPL upstaged 13.3%. For identification of metastatic RLPN with technetium, sensitivity was 33%, specificity 79%, positive predictor value (PPV) 29%, negative predictor value (NPV) 83% and false negative (FN) rate 67%. For patent blue and technetium metastatic RLPN identification, sensitivity was 17%, specificity 92%, PPV 33%, NPV 82% and FN 83%. CONCLUSIONS: Preliminary results have pointed out technetium and blue dye low accuracy to identify metastatic RLPN; no metastatic RLPN were reported in the patients submitted to preoperative chemoradiation and important upstaging with RLPL. Considering no increase in morbi-mortality rates with RLPL, definitive conclusions will be obtained as the study carries on.

Adenocarcinoma↗
PubMed2004

Separation of stereoisomers of some terpene derivatives by capillary gas chromatography-mass spectrometry and high-performance liquid chromatography using beta-cyclodextrin derivative columns.

Gas chromatographic separations of the stereoisomers of menthol derivatives, important intermediates in the synthesis of physiologically active natural products, were carried out on several substituted beta-cyclodextrin (CD) columns, including per-O-methyl-beta-cyclodextrin (PME-beta-CD), heptakis(2,3-di-O-acetyl-6-tert-butyldimethylsilyl)-beta-CD (DIAC-6-TBDS-beta-CD), and heptakis(2,3-di-O-methyl-6-tert-butyldimethylsilyl)-beta-CD (DIME-6-TBDS-beta-CD) as chiral stationary phases (CSPs). With the DIME-6-TBDS-beta-CD column, a separation of the Z- and E-isomers of methylidenementhol was accomplished; no separation was achieved with the other columns. The stereoisomers of methylidenementhol and the corresponding tert-butyldimethylsilyl (TBS) ether were separated on both the beta-CD and the heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (TME-beta-CD) columns by high-performance liquid chromatography (HPLC) with a mobile phase involving acetonitrile and H(2)O. For the separation of the Z- and E-isomers of methylidenementhol, the TME-beta-CD column was superior. In contrast, the beta-CD column was preferable in the case of the corresponding TBS ether.

Chromatography, High Pressure Liquid↗
PubMed2026

Single-cell and spatial transcriptomics define a progenitor subpopulation and fibroinflammatory niche at the leading edge of parathyroid carcinoma.

Parathyroid carcinoma (PC) is a rare but clinically aggressive endocrine malignancy with limited treatment options and a poorly defined tumor microenvironment (TME). To elucidate its cellular heterogeneity and spatial architecture, we integrated single-cell and spatial transcriptomic profiling with whole-exome sequencing and multiplex immunohistochemistry on eight parathyroid neoplasm specimens, including PC, parathyroid adenoma, and atypical parathyroid tumor. We identified a distinct progenitor-like endocrine subpopulation (Ca-1) enriched in CDC73-mutant PC, exhibiting stem-like properties, elevated cell cycle activity, and pronounced genomic instability. Spatial mapping revealed that Ca-1 cells preferentially localize at the leading edge, forming a fibroinflammatory niche characterized by the enrichment of inflammatory cancer-associated fibroblasts (iCAFs) and SPP1+ macrophages. Within this niche, the dipeptidyl peptidase 4 (DPP4) is selectively expressed in Ca-1 cells and iCAFs, implicating a potential paracrine axis driving stromal remodeling and immunosuppression. These findings suggest that a spatially organized ecosystem may promote PC progression through TME remodeling and highlight the DPP4-CXCL2 axis as a candidate pathway for future investigation in aggressive parathyroid neoplasms.

Humans↗
PubMed2003

Risk management of the transmissible spongiform encephalopathies in North America.

As North American Free Trade Agreement partners, Canada, the United States of America (USA) and Mexico apply independent but harmonised transmissible spongiform encephalopathy (TSE) risk management strategies in observance of Office International des Epizooties guidelines. The divergence between bovine spongiform encephalopathy (BSE) risk management approaches in North American and Europe reflects comparatively reduced external and internal BSE risks in North America. The external quarantine and internal surveillance measures adopted for BSE respond to several iterations of national risk assessments initiated in the early 1990s and revised as recently as 2002. Feed bans applied since 1997 to preclude establishment of BSE also bear the potential to limit intra-species and inter-species exposure to scrapie, chronic wasting disease (CWD) and transmissible mink encephalopathy (TME). Surveillance continues for the four TSEs through collaborative efforts of national and sub-national veterinary infrastructures and accompanying laboratory networks. Mexico has never identified the presence of any TSE. The last diagnosed case of TME in North America dates back to 1985. Since the only recognised appearance in Canada through an import from Great Britain in 1993, BSE has not been detected in North America. Scrapie and CWD remain at generally low prevalence in Canada and the USA. Independent but harmonised eradication programmes target elimination of the latter two diseases.

Animal Husbandry↗
PubMed2026

Integrated bioinformatics analyses for GSDMB in carcinogenesis and progression of bladder cancer.

BACKGROUND: Emerging evidence suggests that pyroptosis influences the development of various diseases. Gasdermin B (GSDMB), an intracellular protein that executes pyroptosis, has recently attracted attention for its potential role in tumor biology. However, its specific function in bladder cancer (BLCA) remains unclear. Therefore, this study aimed to investigate the potential role of GSDMB in the carcinogenesis and prognosis of BLCA patients. METHODS: Mendelian randomization (MR) studies were conducted to examine relationships between the expression of GSDMB and BLCA with expression quantitative trait loci (eQTL) data. Then, GSDMB mRNA expression data and clinical characteristics of BLCA patients were retrieved from The Cancer Genome Atlas (TCGA) database. Cox regression was used to explore the relationship between GSDMB mRNA expression and patients' survival. Additionally, the correlation between GSDMB and the immune microenvironment, tumor mutational burden (TMB), tumor microenvironment (TME), and drug sensitivity in BLCA was examined. RESULTS: According to MR analysis based on eQTLs, GSDMB mRNA expression has positive causal effects on bladder carcinogenesis and the need for bladder surgery (P<0.05). The analyses of TCGA demonstrated an increased expression of GSDMB in BLCA tissues, correlating with improved patient survival. Additionally, elevated GSDMB mRNA expression was identified as an independent protective prognostic factor for BLCA, and it was associated with immune cell infiltration, TMB, TME score, and drug sensitivity. CONCLUSIONS: Elevated mRNA expression of GSDMB has a causal link to a higher risk of BLCA and the likelihood of bladder surgery, but also indicates a better prognosis. Thus, GSDMB exhibits dual effects and might serve as a potential biomarker for predicting onset and progression of BLCA. Nevertheless, further investigation of pathogenesis and mechanisms underlying GSDMB is warranted.

Bladder cancer (BLCA)↗
PubMed2026

Overexpression of TCF7L2 promotes the viability and migration of MHCC-97H human hepatocellular carcinoma cells by upregulating MT-ND4L.

BACKGROUND: Hepatocellular carcinoma (HCC) is a highly aggressive cancer with high metabolic adaptability. TCF7L2, a transcription factor implicated in type 2 diabetes and cancer, is overexpressed in HCC. However, its specific role in HCC metabolic reprogramming is not well defined. We aimed to elucidate the previously unrecognized molecular mechanisms through which TCF7L2 impacts HCC progression. METHODS: To investigate the function of TCF7L2, a stable MHCC-97H cell line with TCF7L2 overexpression was established via lentiviral transduction. Cell viability and migration were assessed by Cell Counting Kit-8 (CCK-8) and Transwell assays. Transcriptomic profiling [RNA sequencing (RNA-seq)] was performed to identify differentially expressed genes (DEGs). Functional enrichment analysis [Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Set Enrichment Analysis (GSEA)] and bioinformatics promoter analysis (the JASPAR CORE database) were conducted. Clinical correlations, survival analysis, and tumor microenvironment (TME) interrogation were performed using The Cancer Genome Atlas Liver Hepatocellular Carcinoma (TCGA-LIHC) cohort and single-cell datasets [Human Protein Atlas (HPA), CellChat]. Drug sensitivity was predicted via the Genomics of Drug Sensitivity in Cancer (GDSC) database. RESULTS: TCF7L2 overexpression significantly promoted HCC cell proliferation and migration. Transcriptomic analysis revealed that TCF7L2 drives a profound metabolic shift, with key enrichments in lipid homeostasis, fatty acid &#x3b2;-oxidation, and the PI3K/Akt pathway. Mechanistically, TCF7L2 directly binds to the promoter of CPT1A, the rate-limiting enzyme of fatty acid oxidation, and indirectly upregulates the mitochondrial gene MT-ND4Lvia a strong positive correlation with the mitochondrial transcription factor TFAM. In clinical cohorts, TCF7L2 was overexpressed in HCC and its expression correlated positively with MT-ND4L, MKI67, and SNAI1, and served as a predictor of poor overall survival (OS). Furthermore, TCF7L2-high tumors were enriched in hepatic progenitor cell (HPC)-like niches, mediated by enhanced ANGPTL4 signaling. High TCF7L2 expression predicted increased sensitivity to PI3K/mTOR pathway inhibitors. CONCLUSIONS: TCF7L2 acts as a master metabolic regulator in HCC, coordinating lipid catabolism and mitochondrial biogenesis to drive aggressive tumor behavior. It further remodels the TME towards an HPC-like state and predicts sensitivity to metabolic-targeted therapies. These findings identify TCF7L2 as a key prognostic biomarker and a promising therapeutic target.

MHCC-97H hepatocellular carcinoma cells (MHCC-97H ↗
PubMed2026

Lipid metabolic reprogramming of tumor-associated macrophages drives resistance to immune checkpoint blockade in lung cancer: a narrative review of mechanisms and therapeutic strategies.

BACKGROUND AND OBJECTIVE: Immune checkpoint inhibitors (ICIs), represented by programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1), have shown remarkable efficacy in non-small cell lung cancer (NSCLC); however, many patients still develop resistance to immunotherapy. Although small cell lung cancer (SCLC) is also an important histological type of lung cancer, NSCLC accounts for the majority of lung cancer cases. Current research on ICI development, first-line treatment efficacy, and the mechanisms of lipid metabolism in tumor-associated macrophages (TAMs) is predominantly focused on NSCLC. In patients with advanced NSCLC, objective response rates (ORRs) with PD-1/PD-L1 inhibitor monotherapy remain limited. Only in patients with high PD-L1 expression [tumor proportion score (TPS) &#x2265;50%] and without sensitizing epidermal growth factor receptor (EGFR) mutations or anaplastic lymphoma kinase (ALK) rearrangements does the ORR increase to approximately 40-45%. TAMs are a key component of the immunosuppressive tumor microenvironment (TME). Lipid metabolic reprogramming profoundly influences the functional and transcriptional features of TAMs. This review aims to integrate relevant evidence, elucidate how TAM lipid metabolism promotes immunosuppression and resistance to ICIs, and outline potential therapeutic strategies. METHODS: We searched PubMed/MEDLINE, Web of Science, and Scopus for publications up to June 2026 using terms combining lung cancer, TAMs, lipid metabolism, and immune checkpoint blockade/resistance. Mechanistic, translational, and clinically relevant studies were selected by author consensus. KEY CONTENT AND FINDINGS: Lipid uptake, de novo lipogenesis, fatty acid oxidation (FAO), cholesterol remodeling, and eicosanoid metabolism are not independent processes in TAMs. Lipid metabolic reprogramming in TAMs ultimately suppresses type I interferon (IFN-I) signaling, upregulates PD-L1 expression, and impairs the function of CD8+ T cells with stem-like features, thereby establishing an immunosuppressive TME and leading to resistance to ICIs. In lung cancer, hypoxia, high lactate levels, and tobacco exposure further shape the lipid phenotype of TAMs, such as lipid raft enrichment and lipid-laden macrophage subsets like SPP1+ macrophages. Different driver genomic backgrounds differentially impact tumor cell-intrinsic metabolism and the lipid metabolic programs of myeloid cells. In preclinical models, interventions targeting these metabolic axes, including TAM-directed delivery systems, have demonstrated potential therapeutic benefit when combined with anti-PD-1/PD-L1 therapy. CONCLUSIONS: Targeting TAM lipid metabolism to convert immunologically cold tumors into more inflamed, ICI-responsive tumors is a promising strategy to overcome resistance in NSCLC. Identification of predictive biomarkers of therapeutic response and development of cell-selective drug delivery systems come to be major challenges.

Non-small cell lung cancer (NSCLC)↗
PubMed2006

Straight and colonic J-pouch reconstruction after low anterior resection.

PURPOSE: A complication after restorative rectal surgery with a straight anastomosis is low-anterior resection syndrome with a postoperatively deteriorated anorectal function. The colonic J-reservoir is sometimes used with the purpose of reducing these symptoms. An alternative method is to use a simple side-to-end anastomosis or a coloplasty. MATERIAL AND METHODS: Three-hundred fiftyseven patients with rectal cancer undergoing total mesorectal excision (TME). Three-hundred (84.0%) received a low anterior resection with primary anastomosis and colo-rectal n = 194 (64.6%) or colo-anal anastomosis n = 106 (35.3%). A colonic pouch using the descending colon was created in 24 patients and in 75 patients respectively. Surgical results and complications were recorded. Patients were followed with a functional evaluation at 6 and 12 months postoperatively. RESULTS: Patient characteristics in both groups were very similar regarding gender, age, tumor level, and Dukes' stages. A large proportion of the patients received short-term preoperative radiotherapy (72%). There was no significant difference in surgical outcome between the 2 techniques with respect to anastomotic height, perioperative blood loss, postoperative complications, reoperations, hospital stay or pelvic sepsis rates except the anastomotic stricture rate in the colonic J-Pouch group after coloanal anastomosis (p < 0.02). CONCLUSIONS: These data show that either a colonic J-pouch or a straight anastomosis performed on the descending colon in low-anterior resection with TME are methods that can be used with similar expected surgical and functional results.

Anal Canal↗
PubMed1990

Study of the mode of action of some nitrodiphenyl ethers.

Nitrosoderivatives of the nitrodiphenyl ether herbicides (nitrofen, bifenox) have been studied. UV irradiation in different organic solvents gives degradation products. In buffered aqueous media, in the presence of chloroplasts and spin traps such as DMPO, hydroxy and peroxy radicals have been characterized. In organic media and in the presence of spin traps such as DMPO, PBN, 4-POBN, solvent radicals (.CHCl2, .CCl3, .CH2 [symbol: see text]) have been formed. Nitro-derivatives have been studied under UV irradiation and in the presence of tetramethylethylene (TME), alkenylhydroxylamines are formed which autoxidize in nitroxide radicals. The formation of the stable nitroxide radical occurs in the dark process after continuous irradiation. The intensity of the signal decreases strongly when a new irradiation is applied. Radical species, with analogous ESR spectral characteristics are formed on reaction with nitrodiphenyl ethers and fatty acids. The reactivity of these herbicides in micellar media (SDS, Brij 35, and CTAB) has been investigated. The kinetics of formation of the ESR signal corresponding to the photoreduction of the nitrodiphenyl ether in the presence of TME behave differently in a micellar environment as compared to solution. The intensity of the formation of the nitroxide increases under irradiation and decreases in the dark; the rotational correlation time tau c has been determined for each type of micelle. Synthetic nitrosodiphenyl ether made by the reduction of nitrodiphenyl ether using hydrogen gas and PtO2 as a catalyst gives the corresponding amine, which is oxidized with meta-chloroperbenzoic acid (m.CPBA). The nitrosodiphenyl ether in the presence of soja azolectin liposome containing a fluorescent probe has been analysed.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemical Phenomena↗
PubMed1980

True metabolizable energy values for poultry of commercial diets measured by bioassay and predicted from chemical data.

Data describing 419 commercial poultry feeds and 41 mixtures of feedingstuffs were used to develop multiple linear regression equations for predicting the true metabolizable energy (TME) values of mixed feeds. Equations using the three-variable combinations "ether extract, crude fiber, ash" and "ether extract, crude protein, NFE" were equally useful as predictors of TME, explaining about 80% of the variation. The combination "ether extract, crude protein, carbohydrate", used in published equations for predicting apparent metabolizable energy, explained only about 60% of the variation. Equations with four or more variables were not significantly better than the three-variable equations. The commercial data were split into three groups. Equations developed on the separate groups were consistent. The equations are recommended for use with mixed feeds whose parameters fall within the ranges of the values observed in the experiment.

Animal Nutritional Physiological Phenomena↗
PubMed1980

Bioavailable amino acids in corn and alfalfa as measured by applying the true metabolizable energy assay.

Amino acid (AA) availabilities were determined in three different samples of corn and one of dehydrated alfalfa using the true metabolizable cnergy (TME) assay and force-feeding the ingredients both singly and mixed with a basal diet. One of the corn samples and the alfalfa were those used in the ANRC collabortative study on metabolizable energy (Sibbald, 1978). The other two corn samples were the same cultivar but one (corn D) was afflicted with the fungal disease, "eye spot" (kabatiella zeae), and had a lower hectoliter weight than the nondiseased counterpart (corn ND). Values were calculated for both the apparent AA availability (AAAA) and true AA variability (TAAA), i.e., corrected for the metabolic and endogenous AA losses. Some of the AAAA values for corn ND and corn D varied appreciably with the method of feeding, but such variations were not reflected in the TAAA values. However, the AAAA and TAAA values of alfalfa were generally similar when fed alone or mixed with the basal diet. For the ANRC corn sample both the parameters varied substantially with generally higher AAAA and TAAA values being obtained by feeding the corn mixed with the basal diet. The AA availability values of corn D were very similar to those of its counterpart corn ND as well as the ANRC corn. Discussed are the implications of measuring AA availability in feedstuffs applying the TME assay and using the ingredients as such or as a complete diet.

Amino Acids↗
PubMed1981

Effect of blending and level of inclusion on the metabolizable energy of tallow and tower rapeseed soapstocks.

Experiments were conducted with prime tallow (PT) and Tower rapeseed soapstocks (TSS) to determine the possible synergism between these fats by the total collection and chromic oxide (Cr2O3) apparent metabolizable energy (AME) methods as well as the true metabolizable energy (TME) assay and to examine the effect of inclusion level on the metabolizable energy (ME) values of fats. Graded levels of 0, 3, 6, and 9% of each of PT, TSS, and a 1:1 blend of the two were fed to groups of adult roosters, and the ME values of the test fats and the mixture were evaluated from a linear regression of the ME of the diets and the levels of fat inclusion. The total collection and Cr2O3 methods gave essentially the same AME values for PT as well as for TSS when these fats were fed separately. The 1:1 blend of these fats gave a somewhat higher value with the index method than with the total collection procedure. A positive synergistic effect of blending PT with TSS was observed in all three methods. Increases in the observed ME of the mixture over the calculated ME were 3.94, 5.26, and 5.72%, respectively, for the total collection, Cr2O3, and TME assays. When calculated by difference, the ME values of the two fats and the blend varied widely with inclusion level in all three assay procedures. The implications of use of a single level assay to determine the ME content of fats are discussed.

Animal Feed↗
PubMed1984

A preliminary investigation of the utilization of true metabolizable energy by chicks.

The change in carcass composition associated with intake of true metabolizable energy (TME) by young broiler chicks was investigated. The experiment comprised 17 treatments, 16 of which formed a 2 X 4 X 2 factorial design with six replications; the experimental unit was a pen of four male chicks. The factorial treatments consisted of two basal diets (lipogenic and proteogenic ), four levels of cellulose dilution (to cause a range of basal diet intakes), and two feeding periods (10 to 17 and 10 to 24 days of age). The birds were fed ad libitum, feed intake was recorded, and final carcass composition was measured. The 17th treatment comprised 24 pens of chicks killed at the start of the experiment to estimate initial carcass composition. The gross energy of carcass fat and protein was estimated by chemical and physical analysis and by regression analysis, the latter yielded estimates of 24.5 and 39.5 MJ/kg for protein and fat, respectively. Basal diet intake was reduced by more than 50% at the highest level of cellulose dilution and increased by about 60% when the feeding period was extended from 17 to 24 days. Pen weight gain and carcass composition were affected by basal diet intake. The energy retained in the carcass (MJ/W X 75 kg/day) (RE') increased in a linear manner with the intake of TME (MJ/W X 75 kg/day) ( ITME ), the slope of the line being greater for the lipogenic than for the proteogenic diet. Projected back to zero ITME ', the regression lines for pens in positive energy balance gave an estimate of .420 MJ loss, After 7 days on experiment, the energy retained as fat (RE'f) and as protein (RE'p) increased approximately linearly with ITME ', but after 14 days some curvature was apparent, the deposition of protein increasing more rapidly at the lower levels of energy input, and the deposition of fat increasing more rapidly at the higher levels of energy input. The RE'p was only slightly higher on the proteogenic diet than on the lipogenic diet, at the same level of ITME ', but the effect of basal diet on RE'f was considerable. For both diets at RE' = 0 there was gain in body protein accompanied by loss of body fat.

Animal Feed↗
PubMed1985

The bioavailability of supplementary lysine and its effect on the energy and nitrogen excretion of adult cockerels fed diets diluted with cellulose.

A basal diet formulated to be deficient in lysine was supplemented with five levels of L-lysine monohydrochloride and each of the resulting diets was diluted with six levels of cellulose. Each of the 30 diets was precision fed (30 g/bird) to adult cockerels which had been fasted for 24 hr, and excreta voided during the 48 hr following feeding were collected. Twelve fasted birds served as controls. Feed and excreta samples were assayed for lysine, energy, and nitrogen. The bioavailability of the natural lysine was 88.2 +/- 2.5% whereas that of the L-lysine HCl was approximately 92%, significantly (P less than .05) less than the 100% often assumed in lysine requirement studies. The supplemental lysine did not significantly affect (P greater than .05) estimates of bioavailable energy [true metabolizable energy (TME), TME corrected to zero nitrogen balance (TMEn)]. Cellulose dilution had no significant (P greater than .05) effect on either lysine or energy availability.

Animals↗
PubMed1986

Prediction of metabolizable energy of broiler diets from chemical analysis.

Eighty-six broiler diets were studied to develop prediction equations for true metabolizable energy (TME) with nitrogen correction (TMEn) and calculated apparent metabolizable energy (AMEn) from chemical composition. Analyses were selected according to their capacity to represent the terms used in energy calculations, namely, dietary gross energy and energy excreted relative to diet consumed. Dietary gross energy was found to be highly correlated with ether extract alone. Prediction of excreta loss improved substantially with inclusion of two terms: a measurement of fiber [either crude fiber (CF), acid detergent fiber (ADF), or neutral detergent fiber (NDF)] and ash. A composite variable based on starch plus crude protein in place of fiber and ash yielded similar predictions. Accuracy of prediction of TMEn approached that of the biological analysis, but prediction of TME was somewhat less successful. Neutral detergent fiber was less satisfactory as a predictor than ADF or CF. Calculated AMEn was also highly predictable from ether extract or diet gross energy and a measurement of fiber alone; ash apparently was less helpful for AMEn. Previously published equations based on ether extract, ash, and an estimate of fiber gave results similar to the derived equations.

Animals↗
PubMed1989

Standard errors of nitrogen-corrected true metabolizable energy estimates: effects of pooling excreta samples and ignoring among-control bird variation.

To estimate TME(n), it appears to be advantageous to pool excreta samples prior to analysis for energy and nitrogen; accurate (nonbiased) estimates should result. With this protocol, estimates of precision are based entirely on the among-bird variance in excreta weight of the fed birds. However, because of the inconsistent relationship between excreta weight and excreta energy, the SE resulting from this pooling protocol generally are unrelated to the correct values obtained when the energy and nitrogen concentrations are measured in the excreta of each bird. Failure to account for the among-control-bird variation in excreta energy overstates the precision (i.e. underestimates the SE) of TME(n) estimates.

Analysis of Variance↗
PubMed1992

Research note: effect of high ambient temperature on dietary metabolizable energy values in genetically lean and fat chickens.

Effect of high ambient temperature (32 versus 22 C) on dietary ME value was investigated in 32 genetically lean and fat 8-wk-old male chickens. Lean broilers exhibited higher AME and TME values than fat chickens. Hot climatic conditions significantly increased AME and TME values, particularly in leaner birds. Protein retention efficiency was enhanced by selection for leanness and increased with ambient temperature. Correction for nitrogen balance (AME(n) and TMEn) reduced the effect of temperature but lean genotypes still revealed higher TMEn values than fatter ones.

Animals↗