To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The COVID-19 pandemic has had a profound impact on the mental health of healthcare workers (HCWs). We aimed to identify the factors associated with depression among HCWs during the pandemic. We conducted literature search using eight electronic databases up to July 27 2022. Observational studies with more than 200 participants investigating correlates of depression in HCWs after COVID-19 outbreak were included. We used fixed- and random-effects models to pool odds ratios (ORs) across studies, and Cochran's chi-squared test and I2 statistics to assess study heterogeneity. Publication bias was evaluated by funnel plots. Thirty-five studies involving 44,362 HCWs met the inclusion criteria. Female (OR=1.50, 95% CI [1.23,1.84]), single (OR=1.36, 95% CI [1.21,1.54]), nurse (OR=1.69, 95% CI [1.28,2.25]), history of mental diseases (OR=2.53, 95% CI [1.78,3.58]), frontline (OR=1.79, 95% CI [1.38,2.32]), health anxiety due to COVID-19 (OR=1.88, 95% CI [1.29,2.76]), working in isolation wards (OR=1.98, 95% CI [1.38,2.84]), and insufficient personal protective equipment (OR=1.49, 95% CI [1.33,1.67]) were associated with increased risk of depression. Instead, HCWs with a positive professional prospect (OR=0.34, 95% CI [0.24,0.49]) were less likely to be depressed. This meta-analysis provides up-to-date evidence on the factors linked to depression among HCWs during the COVID-19 pandemic. Given the persistent threats posed by COVID-19, early screening is crucial for the intervention and prevention of depression in HCWs.
Widely distributed Mid-Neoproterozoic mafic rocks of the Qilian – Qaidam – East Kunlun region record the tectonic evolution of the northeastern Tibetan Plateau. This study presents whole-rock geochemistry, zircon U–Pb geochronology and Hf isotopes for the Xialanuoer gabbros of the central South Qilian Belt (SQB). Zircon laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS) U–Pb dating indicates that the gabbros were emplaced at ca. 738 Ma, indicating they are contemporaneous with mafic magmatism elsewhere in the northeastern Tibetan Plateau. The gabbros have low SiO2, Cr and Ni contents and Mg# values, are relatively enriched in light rare-earth elements (LREEs) and depleted in high-field-strength elements (HFSEs; e.g. Nb and Ta), have no positive Zr or Hf anomalies and have relatively high Nb/Ta but low Nb/La ratios. These data indicate that the Xialanuoer gabbros formed from calc-alkaline basaltic magmas that were originally generated by the partial melting of an enriched mantle of type-I (EMI-type) enriched region of the lithospheric mantle, underwent little to no crustal contamination prior to their emplacement, and have within-plate basalt geochemical affinities. Combining these data with the presence of widespread contemporaneous continental rift-related magmatism and sedimentation in the North Qilian, Central Qilian, South Qilian, Quanji, North Qaidam and East Kunlun regions suggests that the northeastern Tibetan Plateau underwent Mid-Neoproterozoic continental rifting, which also affected other Rodinian blocks (e.g. Tarim, South China, Australia, North America and Southern Africa).
Poor utilisation efficiency of carbohydrate always leads to metabolic phenotypes in fish. The intestinal microbiota plays an important role in carbohydrate degradation. Whether the intestinal bacteria could alleviate high-carbohydrate diet (HCD)-induced metabolic phenotypes in fish remains unknown. Here, a strain affiliated to Bacillus amyloliquefaciens was isolated from the intestine of Nile tilapia. A basal diet (CON), HCD or HCD supplemented with B. amy SS1 (HCB) was used to feed fish for 10 weeks. The beneficial effects of B. amy SS1 on weight gain and protein accumulation were observed. Fasting glucose and lipid deposition were decreased in the HCB group compared with the HCD group. High-throughput sequencing showed that the abundance of acetate-producing bacteria was increased in the HCB group relative to the HCD group. Gas chromatographic analysis indicated that the concentration of intestinal acetate was increased dramatically in the HCB group compared with that in the HCD group. Glucagon-like peptide-1 was also increased in the intestine and serum of the HCB group. Thus, fish were fed with HCD, HCD supplemented with sodium acetate at 900 mg/kg (HLA), 1800 mg/kg (HMA) or 3600 mg/kg (HHA) diet for 8 weeks, and the HMA and HHA groups mirrored the effects of B. amy SS1. This study revealed that B. amy SS1 could alleviate the metabolic phenotypes caused by HCD by enriching acetate-producing bacteria in fish intestines. Regulating the intestinal microbiota and their metabolites might represent a powerful strategy for fish nutrition modulation and health maintenance in future.
Hypertension represents one of the most common pre-existing conditions and comorbidities in Coronavirus disease 2019 (COVID-19) patients. To explore whether hypertension serves as a risk factor for disease severity, a multi-centre, retrospective study was conducted in COVID-19 patients. A total of 498 consecutively hospitalised patients with lab-confirmed COVID-19 in China were enrolled in this cohort. Using logistic regression, we assessed the association between hypertension and the likelihood of severe illness with adjustment for confounders. We observed that more than 16% of the enrolled patients exhibited pre-existing hypertension on admission. More severe COVID-19 cases occurred in individuals with hypertension than those without hypertension (21% vs. 10%, P = 0.007). Hypertension associated with the increased risk of severe illness, which was not modified by other demographic factors, such as age, sex, hospital geological location and blood pressure levels on admission. More attention and treatment should be offered to patients with underlying hypertension, who usually are older, have more comorbidities and more susceptible to cardiac complications.
In higher plants, fertilization induces many structural and physiological changes in the fertilized egg that reflect the transition from the haploid female gamete to the diploid zygote – the first cell of the sporophyte. After fusion of the egg nucleus with the sperm nucleus, many molecular changes occur in the zygote during the process of zygote activation during embryogenesis. The zygote originates from the egg, from which some pre-stored translation initiation factors transfer into the zygote and function during zygote activation. This indicates that the control of zygote activation is pre-set in the egg. After the egg and sperm nuclei fuse, gene expression is activated in the zygote, and paternal and maternal gene expression patterns are displayed. This highlights the diversity of zygotic genome activation in higher plants. In addition to new gene expression in the zygote, some genes show quantitative changes in expression. The asymmetrical division of the zygote produces an apical cell and a basal cell that have different destinies during plant reconstruction; these destinies are determined in the zygote. This review describes significant advances in research on the mechanisms controlling zygote activation in higher plants.
A high-carbohydrate diet could achieve a protein-sparing effect, but it may cause negative impacts on the growth condition of fish due to their poor utilisation ability of carbohydrate. How to reduce the adverse effects caused by a high-carbohydrate diet is important for the development of aquaculture. In the present study, we aimed to identify whether inulin could attenuate the metabolic syndrome caused by a high-carbohydrate diet in fish. Nile tilapia (Oreochromis niloticus) (1·19 (sd 0·01) g) were supplied with 35 % carbohydrate (CON), 45 % carbohydrate (HC) and 45 % carbohydrate + 5 g/kg inulin (HCI) diets for 10 weeks. The results showed that addition of inulin improved the survival rate when fish were challenged with Aeromonas hydrophila, indicating that inulin had an immunostimulatory effect. Compared with the HC group, the HCI group had lower lipid accumulation in liver and the gene expression analyses indicated that addition of inulin down-regulated genes related to lipogenesis and up-regulated genes relevant to β-oxidation significantly (P < 0·05). Higher liver glycogen and glucose tolerance were found in the HCI group compared with the HC group (P < 0·05). These results indicated that inulin could alleviate the metabolic syndrome induced by a high-carbohydrate diet. Furthermore, addition of inulin to a high-carbohydrate diet changed the intestinal bacterial composition and significantly increased the concentration of acetic acid and propionic acid in fish gut which have the potential to increase pathogen resistance and regulate metabolic characteristics in fish. Collectively, our results demonstrated a possible causal role for the gut microbiome in metabolic improvements induced by inulin in fish.
l-Carnitine is essential for mitochondrial β-oxidation and has been used as a lipid-lowering feed additive in humans and farmed animals. d-Carnitine is an optical isomer of l-carnitine and dl-carnitine has been widely used in animal feeds. However, the functional differences between l- and d-carnitine are difficult to study because of the endogenous l-carnitine background. In the present study, we developed a low-carnitine Nile tilapia model by treating fish with a carnitine synthesis inhibitor, and used this model to investigate the functional differences between l- and d-carnitine in nutrient metabolism in fish. l- or d-carnitine (0·4 g/kg diet) was fed to the low-carnitine tilapia for 6 weeks. l-Carnitine feeding increased the acyl-carnitine concentration from 3522 to 10 822 ng/g and alleviated the lipid deposition from 15·89 to 11·97 % in the liver of low-carnitine tilapia. However, as compared with l-carnitine group, d-carnitine feeding reduced the acyl-carnitine concentration from 10 822 to 5482 ng/g, and increased lipid deposition from 11·97 to 20·21 % and the mRNA expression of the genes involved in β-oxidation and detoxification in the liver. d-Carnitine feeding also induced hepatic inflammation, oxidative stress and apoptosis. A metabolomic investigation further showed that d-carnitine feeding increased glycolysis, protein metabolism and activity of the tricarboxylic acid cycle and oxidative phosphorylation. Thus, l-carnitine can be physiologically utilised in fish, whereas d-carnitine is metabolised as a xenobiotic and induces lipotoxicity. d-Carnitine-fed fish demonstrates increases in peroxisomal β-oxidation, glycolysis and amino acid degradation to maintain energy homeostasis. Therefore, d-carnitine is not recommended for use in farmed animals.
Although parasites and microbial pathogens are both detrimental to insects, little information is currently available on the mechanism involved in how parasitized hosts balance their immune responses to defend against microbial infections. We addressed this in the present study by comparing the immune response between unparasitized and parasitized pupae of the chrysomelid beetle, Octodonta nipae (Maulik), to Escherichia coli invasion. In an in vivo survival assay, a markedly reduced number of E. coli colony-forming units per microliter was detected in parasitized pupae at 12 and 24 h post-parasitism, together with decreased phagocytosis and enhanced bactericidal activity at 12 h post-parasitism. The effects that parasitism had on the mRNA expression level of selected antimicrobial peptides (AMPs) of O. nipae pupae showed that nearly all transcripts of AMPs examined were highly upregulated during the early and late parasitism stages except defensin 2B, whose mRNA expression level was downregulated at 24 h post-parasitism. Further elucidation on the main maternal fluids responsible for alteration of the primary immune response against E. coli showed that ovarian fluid increased phagocytosis at 48 h post-injection. These results indicated that the enhanced degradation of E. coli in parasitized pupae resulted mainly from the elevated bactericidal activity without observing the increased transcripts of target AMPs. This study contributes to a better understanding of the mechanisms involved in the immune responses of a parasitized host to bacterial infections.
To investigate the protein-sparing effect of α-lipoic acid (LA), experimental fish (initial body weight: 18·99 (sd 1·82) g) were fed on a 0, 600 or 1200 mg/kg α-LA diet for 56 d, and hepatocytes were treated with 20 μm compound C, the inhibitor of AMP kinase α (AMPKα), treated for 30 min before α-LA treatment for 24 h. LA significantly decreased lipid content of the whole body and other tissues (P<0·05), and it also promoted protein deposition in vivo (P<0·05). Further, dietary LA significantly decreased the TAG content of serum and increased the NEFA content of serum (P<0·05); however, there were no significant differences among all groups in the hepatopancreas and muscle (P>0·05). Consistent with results from the experiment in vitro, LA activated phosphorylation of AMPKα and notably increased the protein content of adipose TAG lipase in intraperitoneal fat, hepatopancreas and muscle in vivo (P<0·05). Meanwhile, LA significantly up-regulated the mRNA expression of genes involved in fatty acid β-oxidation in the same three areas, and LA also obviously down-regulated the mRNA expression of genes involved in amino acid catabolism in muscle (P<0·05). Besides, it was observed that LA significantly activated the mammalian target of rapamycin (mTOR) pathway in muscle of experimental fish (P<0·05). LA could promote lipolysis and fatty acid β-oxidation via increasing energy supply from lipid catabolism, and then, it could economise on the protein from energy production to increase protein deposition in grass carp. Besides, LA might directly promote protein synthesis through activating the mTOR pathway.
Astrophysical collisionless shocks are amazing phenomena in space and astrophysical plasmas, where supersonic flows generate electromagnetic fields through instabilities and particles can be accelerated to high energy cosmic rays. Until now, understanding these micro-processes is still a challenge despite rich astrophysical observation data have been obtained. Laboratory astrophysics, a new route to study the astrophysics, allows us to investigate them at similar extreme physical conditions in laboratory. Here we will review the recent progress of the collisionless shock experiments performed at SG-II laser facility in China. The evolution of the electrostatic shocks and Weibel-type/filamentation instabilities are observed. Inspired by the configurations of the counter-streaming plasma flows, we also carry out a novel plasma collider to generate energetic neutrons relevant to the astrophysical nuclear reactions.
(1 − x)Ba(Mg1/3Ta2/3)O3–xBa(Co1/3Nb2/3)O3 (BMT–BCN, x = 0.0, 0.20, 0.25, 0.30, 0.40) ceramics were prepared using the traditional solid-state reaction method. X-ray diffraction patterns have shown that the intensities of (001) and (100) super-lattices decrease with the increase in the BCN content. Seven main Raman vibrational modes are observed, assigned, and illustrated, in particular. Raman shifts of Eg(O) modes and the FWHM values of F2g(O)/A1g(O) modes have close relationship with the dielectric properties. The calculated values by the four-parameter semiquantum model based on IR reflectivity match well with the measured data (@3.8 GHz), which means that most of dielectric contribution to the system may be ascribed to the absorption of structural phononic oscillations at the infrared region, and the contribution from the scattering of the defective phonons is small. The contributions of each vibrational mode on the dielectric responses were investigated in detail, indicating that the low-frequency modes (A2u(1) and Eu(1)) have a decisive role to the dielectric properties.
Evaluating quality traits is important to the selection of elite lines in Brassica napus L. In this study, the quality traits of 488 global collections of B. napus L were evaluated for two consecutive years under central Chinese growing conditions, and a series of phenotypic data was obtained. The measured total glucosinolate content (GLC) and erucic acid content (ERU) values for 95.5% of the accessions were consistent with the original values, and large variations in quality traits were found among these accessions, thus enabling selection for these characters. In general, Chinese accessions tended to have a higher oil content (OC) than foreign accessions, while compared with winter and spring accessions, semi-winter accessions tended to have the highest OC. The mean GLC and ERU of Chinese rapeseed accessions showed gradual downward trends over time, and the genotypic variation in ERU accounted for 98.44% of the total variation, which was the highest among all 10 of the quality traits. Additionally, the heritability for ERU was largest among all 10 of the quality traits. Significant correlations were observed between different traits; OC had significantly (P < 0.01) negative correlation coefficients with oleic acid content, whereas OC had significantly (P < 0.01) positive correlation coefficients with ERU. Principal component analysis revealed that there was no clear boundary among materials of different geographic origins and different ecotypes according to the first two principal coordinates, respectively. This information about variations in quality traits revealed in this study could identify parents for improved rapeseed breeding.
We have analyzed core MD01-2392, ∽360 km east of the Mekong River mouth in the South China Sea (SCS). Over the past 500 ka, planktonic foraminiferal oxygen-isotopic values are consistently lighter than northern SCS and open-ocean records by up to 0.5‰, indicating the influence of run-off from the Mekong River during both glacial and interglacial periods. Carbonate content is higher during interglacials; sedimentation rates were higher during glacials. Increased sedimentation rates since 30 ka imply increased run-off during the last glacial maximum and Holocene Period. Contrary to general experience, in which it is classed as a warm species for temperature estimates, the thermocline-dwelling species Pulleniatina obliquiloculata increased its numbers during glacial periods. This implies an estuarine circulation and even brackish-water caps during glacial periods, reinforcing the sense of strong run-off. In an overall decline of warm water, the thermocline shoaled stepwise, with rapid rises across the glacial terminations. We infer that the southern SCS was opened to an influx of Indian Ocean waters through southern passages at those times of rising sea levels.
Cydia pomonella is a serious invasive insect pest in China, and has caused severe damage to the production of apple and pear in its invaded areas. This species is distributing in the northwest and northeast of China, but no occurrence of it has been recorded in the large areas (about 3000–5000 km away) between the invaded northwestern and northeastern regions despite continuous monitoring. As yet the genetic diversity and invasion origin of the C. pomonella populations in Northwestern and Northeastern China is obscure. In this study, we investigate the genetic diversity of 14 populations of C. pomonella sampled throughout the main distribution regions in Northwestern (Xinjiang and Gansu Provinces) and Northeastern (Heilongjiang Province) China and compared them with nine populations from Europe and other continents using the mitochondrial COI, COII and Cytb genes. Both the populations from Northeastern and Northwestern China shared some haplotypes with populations from other countries. Haplotypes of the three mitochondrial genes had a different distribution in Northeastern and Northwestern China. The northeastern populations had more private haplotypes than the northwestern populations. A large number of the individuals from northwestern populations shared a few haplotypes of each of the three genes. The haplotype numbers and haplotype diversities of the northeastern populations were similar to those of field populations in other countries, but were higher than those of the northwestern populations. Populations from the Northwestern China showed similar haplotype number and haplotype diversity. We conclude that the population genetic background of C. pomonella populations in Northeastern and Northwestern China varies due to different invasion sources and that this should be considered before the application of new pest control tactics.
Long-term fertilization experiment has been conducted since 1981 to study the effect of soil management practices on soil fertility, soil carbon and nitrogen sequestration, soil culturable microbe counts and crop yields at the Nanhu Experimental Station in the Hubei Academy of Agricultural Sciences (situated in the middle reach of the Yangtze River and the rice–wheat cropping system). The experiment was designed with the following eight treatments: (1) unfertilized treatment: Control; (2) inorganic nitrogen fertilizer treatment: N; (3) inorganic nitrogen plus inorganic phosphorus fertilizer treatment: NP; (4) inorganic nitrogen, inorganic phosphorus plus inorganic potassium fertilizer treatment: NPK; (5) pig dung compost (manure) treatment: M; (6) inorganic nitrogen fertilizer plus manure: NM; (7) inorganic nitrogen, inorganic phosphorus fertilizer plus manure treatment: NPM and (8) inorganic nitrogen, inorganic phosphorus, inorganic potassium fertilizer plus manure treatment: NPKM. The results showed that long-term application of organic manure in combination with inorganic fertilizer significantly (p < 0.05) increased soil organic C concentrations compared with the corresponding inorganic fertilizers alone. Soil organic C contents were significantly (p < 0.05) increased in balanced application of NPK fertilizers in comparison to unbalanced application of fertilizers. After 30 years of experiment, soil organic C and total N sequestration rate averagely were 0.48 t ha−1 year−1 and 28.3 kg ha−1 year−1 in the fertilized treatments respectively; nevertheless, it were 0.27 t ha−1 year−1 and 9.7 kg ha−1 year−1 in the unfertilized treatment. Application of organic fertilizer in combination with inorganic fertilizer significantly (p < 0.05) increased culturable microbial counts compared with the corresponding inorganic fertilizers alone. The balanced application of NPK fertilizers significantly (p < 0.05) increased culturable microbial counts compared with unbalanced application of fertilizers. The average grain yield of wheat and rice was significantly (p < 0.05) higher in organic manure combined with inorganic fertilizer treatment than in inorganic fertilizer alone and unfertilized control. Therefore, long-term application of organic manure combined with inorganic fertilizer and balanced application of NPK fertilizers could increase soil organic C and total N sequestration, culturable microbial counts and crop grain yields.
We have fabricated Ag-decorated ZnO nanoplate arrays by combining water-bath heating toward ZnO hexagonal nanoplate arrays and subsequent decoration of Ag films or nanoparticles on the ZnO surfaces by magnetron sputtering or photoreduction. Experimental surface-enhanced Raman scattering (SERS) results show that Ag-film–ZnO hybrid substrates with different Ag sputtering times exhibit a large difference in enhanced SERS signals for Rhodamine 6G (10−7 M). Atomic force microscope analysis reveals that two kinds of positions create abundant “hot spots” in this SERS substrate: one is located at the gap between adjacent separate Ag-film–ZnO hybrid nanoplates, and the other is located at the V-grooves formed by two adjacent interlaced Ag-film–ZnO hybrid nanoplates. The effects of simultaneous changes in interplate spacing and groove wall angle are considered to be the key factors affecting the SERS of our prepared Ag-film–ZnO hybrid substrates, which have also been evaluated by finite-difference time-domain simulation.
The Chinese Astronomical Data Center (CAsDC) is a member of World Data System, hosted at National Astronomical Observatories, Chinese Academy of Sciences(NAOC). The CAsDC keeps close collaboration with IVOA, WDS and CODATA. The whole set of LAMOST data, including raw data and data products, are hosted at the CAsDC. Data resources and services of the CAsDC are introduced.
The driving mechanism of solar flares and coronal mass ejections is a topic of ongoing debate, apart from the consensus that magnetic reconnection plays a key role during the impulsive process. While present solar research mostly depends on observations and theoretical models, laboratory experiments based on high-energy density facilities provide the third method for quantitatively comparing astrophysical observations and models with data achieved in experimental settings. In this article, we show laboratory modeling of solar flares and coronal mass ejections by constructing the magnetic reconnection system with two mutually approaching laser-produced plasmas circumfused of self-generated megagauss magnetic fields. Due to the Euler similarity between the laboratory and solar plasma systems, the present experiments demonstrate the morphological reproduction of flares and coronal mass ejections in solar observations in a scaled sense, and confirm the theory and model predictions about the current-sheet-born anomalous plasmoid as the initial stage of coronal mass ejections, and the behavior of moving-away plasmoid stretching the primary reconnected field lines into a secondary current sheet conjoined with two bright ridges identified as solar flares.
Expanded graphite/cobalt ferrite/polyaniline (EG/CF/PANI) ternary composites were obtained by a two-step process. The intercalation compound, CF embedded in EG, was synthesized by a coprecipitation method. PANI could then be coated on the surface of the EG/CF microparticles by in-situ polymerization to form ternary composites of EG/CF/PANI. The results indicate that the electrical and magnetic performance of EG/CF and EG/CF/PANI composites are related to their composition. The EG/CF composite with mass ratio of 1.0 has the maximal conductivity (833.33 S·cm−1) among the binary composites. Saturation magnetizations (Ms) of the EG/CF composite with mEG/mCF of 0.8 is the largest among EG/CF composites, the ternary composites of EG/CF/PANI were prepared from the EG/CF composite at this mass ratio. The electromagnetic wave absorbing property of all ternary composites excelled those of EG/CF composites, and the sample with 40 wt% of PANI has the best absorption properties in the range of 8–18 GHz frequency.
These studies were conducted to determine whether dietary homoarginine, derived from guanidination of synthetic lysine, affects the measurement of apparent and true ileal amino acid digestibility in the pig and to determine the optimal ratio of o-methylisourea (OMIU) to free synthetic lysine in the guanidination reaction that produces homoarginine. In two preliminary experiments, specific amounts of lysine were weighed and added to a solution of 0·6 mol/l OMIU to produce OMIU to free synthetic lysine ratios of 2:1, 1·5:1, 1·4:1, 1·3:1, 1·2:1, 1·1:1 and 1·0:1. The mixture was incubated at a pH of 10·5 and a temperature of 20±1°C for 6 days. The highest yield of homoarginine (proportionately 0·995) was produced with an OMIU to free synthetic lysine ratio of 1·5:1. The serum concentrations of homoarginine and lysine were measured in two test pigs at various times after consuming a single meal containing either homoarginine or lysine. Blood samples were taken before and 0·5, 1·5, 2·5, 4·5, 6·0, 7·5, and 11·5 h after feeding. Thirty minutes after feeding the homoarginine-containing diet, the homoarginine concentration in serum was 0·013 mmol/dl, and increased to a maximum of 0·031 mmol/dl 1·5 h after feeding. Thirty minutes after feeding the lysine-containing diet, the serum lysine concentration was 0·011 mmol/dl and also reached its maximum concentration of 0·025 mmol/dl 1·5 h after feeding. The timing of the changes in concentration of homoarginine and lysine related to feeding were similar, which suggests that homoarginine is absorbed and metabolized in a similar manner to lysine. Six Large White×Landrace barrows, weighing 68·5±3·5 kg and fitted with a simple T-cannula at the distal ileum as well as a jugular vein catheter, were used to determine the effects of homoarginine on endogenous amino acid flows and apparent and true ileal amino acid digestibility. The experimental design was a doubly replicated 3×3 Latin-square design with the three treatments consisting of a lysine-free, zein-based diet and jugular infusion of a lysine solution; a lysine-free, zein-based diet supplemented with homoarginine; and a lysine-free, zein-based diet supplemented with l-lysine. There were no significant differences in endogenous ileal lysine flow for pigs receiving the different treatments (396·6, 407·6, and 360·4 mg/kg DMI, respectively, P=0·71). In addition, with the exception of phenylalanine (P=0·04), there were no significant differences (P>0·10) in the apparent and true ileal digestibility of crude protein and amino acids among the three treatments. Therefore, it would appear that the presence of dietary homoarginine, derived from guanidination of synthetic lysine, does not affect endogenous amino acid losses or the digestibility of crude protein as well as most amino acids. These results are therefore supportive of the use of the homoarginine method as a means of measuring true ileal lysine digestibility.