A total of 144 weaned piglets were used to evaluate the effects of essential oil (EO) supplementation of a low-energy diet on performance, apparent nutrient digestibility, small intestinal morphology, intestinal microflora, immune properties and antioxidant activities in weaned pigs. Pigs received a low-energy diet (negative control, NC, digestible energy = 3250 kcal/kg), NC plus 0.025% EO or a positive control diet (PC, digestible energy = 3400 kcal/kg) for 28 days. Growth performance was similar between the EO group and PC group. However, EO supplementation increased (P < 0.05) average daily gain and the apparent digestibility of dry matter, crude protein and energy compared with pigs fed the NC diet. Greater (P < 0.05) villus height and lower (P < 0.05) counts of Escherichia coli and total anaerobes in the rectum in the EO group were observed compared with NC or PC groups. Pigs fed EO diet had higher (P < 0.05) concentrations of albumin, immunoglobulin A (IgA), IgG and total antioxidant capacity and lower fecal score than pigs fed the PC and NC diets. Above all, this study indicates that supplementation of EO to a low-energy pig diet has beneficial results and obtains similar performance compared with normal energy (PC) diet.

One of the concerns when using grain ingredients in feed formulation for livestock and poultry diets is mycotoxin contamination. Aflatoxin, fumonisin, ochratoxin, trichothecene (deoxynivalenol, T-2 and HT-2) and zearalenone (ZEN) are mycotoxins that have been frequently reported in animal feed. ZEN, which has raised additional concern due to its estrogenic response in animals, is mainly produced by Fusarium graminearum (F. graminearum), F. culmorum, F. cerealis, F. equiseti, F. crookwellense and F. semitectums, and often co-occurs with deoxynivalenol in grains. The commonly elaborated derivatives of ZEN are α-zearalenol, β-zearalenol, zearalanone, α-zearalanol, and β-zearalanol. Other modified and masked forms of ZEN (including the extractable conjugated and non-extractable bound derivatives of ZEN) have also been quantified. In this review, common dose of ZEN in animal feed was summarized. The absorption rate, distribution (“carry-over”), major metabolites, toxicity and estrogenicity of ZEN related to poultry, swine and ruminants are discussed.

This study aimed to compare the risk of infection of children with that of adults and to explore risk factors of infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) by following up close contacts of COVID-19 patients. Method: The retrospective cohort study was performed among close contacts of index cases diagnosed with COVID-19 in Guangzhou, China. Demographic characteristics, clinical symptoms and exposure information were extracted. Logistic regression analysis was employed to explore the risk factors. The restricted cubic spline was conducted to examine to the dose-response relationship between age and SARS-CoV-2 infection. Results: The secondary attack rate (SAR) was 4.4% in 1,344 close contacts. The group of household contacts (17.2%) had the highest SAR. The rare-frequency contact (p < 0.001) and moderate-frequency contact (p < 0.001) were associated with lower risk of infection. Exposure to index cases with dry cough symptoms was associated with infection in close contacts (p = 0.004). Compared with children, adults had a significantly increased risk of infection (p = 0.014). There is a linear positive correlation between age and infection (p = 0.001). Conclusions: Children are probably less susceptible to COVID-19. Close contacts with frequent contact with patients and those exposed to patients with cough symptoms are associated with an increased risk of infection.

Two experiments were conducted to determine the content of digestible energy (DE) and metabolisable energy (ME) as well as the apparent ileal digestibility (AID) and standardised ileal digestibility (SID) of amino acids in peanut meal (PNM) for growing pigs. In Experiment 1, 78 growing pigs (46.8 ± 2.6 kg) were randomly allotted to 1 of 13 diets, including a corn-soya bean meal basal diet and 12 PNM test diets. In Experiment 2, 12 growing barrows (48.7 ± 2.8 kg) were allotted to one of two 6 × 6 Latin squares. The treatments include a N-free diet and 10 PNM test diets. The results of Experiment 1 showed that the DE and ME differed (p < 0.05) among the 12 PNM samples. On a dry matter basis, the DE and ME content ranged from 14.5 to 16.4 MJ/kg (mean 15.6 MJ/kg) and from 12.7 to 15.5 MJ/kg (mean 13.9 MJ/kg), respectively. The apparent total tract digestibility (ATTD) of gross energy (GE) was 82.2%. The DE of PNM could be precisely predicted by equations including NDF combined with GE or crude protein (CP) with an R(2) value of 0.91 and 0.92, respectively. For the AID and SID for lysine, the results of Experiment 2 indicated variations among PNM sources ranging from 59.6% to 76.7% and 64.8% to 80.9%, respectively. However, for CP, variations for AID and SID were lower and ranged from 70.2% to 81.9% and 75.7% to 85.6%, respectively. The results indicate that the concentration of lysine was the best single predictor to estimate the digestibility of amino acids. However, further work is needed to investigate the reason for the variation in the digestibility of lysine and avoid processing procedures that are detrimental to lysine digestibility.

Fluorescein isothiocyanate-dextran ( FITC-d ) is being used as an indicator of intestinal paracellular permeability in poultry research. Especially with the industry moving toward antibiotic-free production, intestinal function and integrity issues have been a research focus. An increasing number of scientific conference abstracts and peer-reviewed journal publications have shown that 4-kDa FITC-d is an efficient marker candidate for measurement of intestinal permeability and can be applied in broiler research. However, experimental protocols vary by personnel, instruments used, and research institution, and potential concerns related to this assay have yet to receive the same amount of attention. Understanding protocol consistency within and across laboratories is vital for obtaining accurate, consistent, and comparable experimental results. This review is aimed to 1) summarize different FITC-d assays in broiler research from peer-reviewed publications during the past 6 yr and 2) discuss factors that can potentially affect intestinal permeability results when conducting the FITC-d assay. In summary, it is essential to pay attention to details, including gavage dose, fasting period, sample handling and lab analysis details when conducting the assay in broiler research. Differences in birds (breed/strain, age, and gender) and experimental design (diet, health status/challenge model, and sampling age) need to be considered when comparing serum FITC-d concentration results between different in vivo animal trials.

Dengue fever (DF) is a mosquito-borne infectious disease that is now an epidemic in China, Guangdong Province, in particular and presents high incidence rates of DF. Effective preventive measures are critical for controlling DF in China given the absence of a licensed vaccination program in the country. This study aimed to explore the individual risk factors for the dengue virus infection in Guangdong Province and to provide a scientific basis for the future prevention and control of DF. A case-control study including 237 cases and 237 controls was performed. Cases were defined for samples who were IgG-antibody positive or IgM-antibody positive, and willing to participate in the questionnaire survey. Additionally, the controls were selected through frequency matching by age, gender and community information from individuals who tested negative for IgG and IgM and volunteered to become part of the samples. Data were collected from epidemiological questionnaires. Univariate analysis was performed for the preliminary screening of 28 variables that were potentially related to dengue virus infection, and multivariate analysis was performed through unconditioned logistic regression analysis to analyze statistically significant variables. Multivariate analysis revealed two independent risk factors: Participation in outdoor sports (odds ratio (OR) = 1.80, 95% confidence interval (CI) 1.17 to 2.78), and poor indoor daylight quality (OR = 2.27, 95% CI 1.03 to 5.03). Two protective factors were identified through multivariate analysis: 2 occupants per room (OR = 0.43, 95% CI 0.28 to 0.65) or ≥3 occupants per room (OR = 0.45, 95% CI 0.23 to 0.89) and air-conditioner use (OR = 0.46, 95% CI 0.22 to 0.97). The results of this study were conducive for investigating the risk factors for dengue virus infection in Guangdong Province. Effective and efficient strategies for improving environmental protection and anti-mosquito measures must be provided. In addition, additional systematic studies are needed to explore other potential risk factors for DF.

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The experiment was conducted to determine the chemical composition, digestible energy (DE), metabolisable energy (ME) and the apparent total tract digestibility (ATTD) in sunflower seed meal (SFSM) and to develop reasonable prediction equations for estimating energy digestibility based on chemical composition of these meals for growing pigs. Ten SFSMs were collected and 66 crossbred barrows (initial body weight=36.43±5.25 kg) were randomly allocated to one of eleven diets. The basal diet was based on corn and soybean meal which contained 82.2% corn, 14.8% de-hulled soybean meal and 3% premix. The test diets contained 30% SFSM at the expense of corn and soybean meals. The experiment comprised a 7-d adaptation period followed by a 5-d collection period of faecal matter and urine. On a dry matter (DM) basis, the content of crude protein, neutral and acid detergent fibre, and gross energy (GE) ranged from 29.33 to 39.09%, 38.15 to 55.40%, 24.59 to 37.34% and 18.65 to 21.50 MJ/kg, respectively. The concentration of DE and ME ranged from 10.51 to 12.47 MJ/kg and 10.26 to 12.16 MJ/kg of DM, respectively. The DE values and ATTD of GE among the ten SFSMs significantly differed (P<0.05). The ATTD of GE ranged from 52.86 to 63.90%. The best models for predicting DE and ME were also established. In conclusion, the chemical composition of SFSM was variable (coeffiecient of variance>10%) among the ten SFSMs (DM). The results of DE, ME and prediction equations could be applied to evaluate the energy digestibility of SFSM in growing pigs.