Poultry Science最新文献

Caused by the Gram-positive bacteria Clostridium perfringens, necrotic enteritis (NE) is an enteric disease with significant economic implications in broiler production. This study employed an experimental NE model involving co-infection with Eimeria maxima and C. perfringens to assess whether sulfate polysaccharides extracted from marine macroalgae could mitigate the adverse effects of NE in broilers. A total of 600 day (d)-old Ross 708 male broilers were randomly assigned to one of four treatment groups: NC (negative control, fed a corn-soybean meal diet); PC (positive control, NC + 15 ppm Avilamycin and 125 ppm Amprolium); AGS (Algimun® Standard, NC + Algimun added at 0.1 % of the diet); and AGH (Algimun High, NC + Algimun added at 0.2 % of the diet). Average daily feed intake and weight gain were calculated and adjusted for daily mortality on d 14, 21, 28, and 42. On d 21, four birds/pen were examined for intestinal NE lesions. On d 14, 21, and 42, serum and jejunum samples from one bird/pen were collected to measure the concentration of the biomarker calprotectin and mRNA abundance of cytokines and tight junction proteins. Data were analyzed using JMP and significance between treatments identified by LSD (P ≤ 0.05). NE lesion scores on d 21, and mortality and FCR during d 0 to 42 were lower in PC, AGS, and AGH compared to NC birds. AGS birds had the lowest levels for serum calprotectin on d 21 while PC, AGS, and AGH had lower levels than the NC group on d 42. On d 14 and d 42, mRNA abundance of CLDN1, 3, ZO1, IL1β, IFNγ, IL10, and IL12B was greater in AGS and AGH birds compared to NC. Also, AGH had a greater abundance of TNFα on d 14 and d 42 compared to NC. Further, mRNA abundance of CLDN3, ZO1, 2, OCLDN, IL1β, IL10, IL12B, IFNγ, and ANXA1 was greater in PC on d 21 compared to NC and AGS. Based on these findings, dietary supplementation of this macroalgae-derived sulfated polysaccharides yielded a similar response to an antibiotic growth promoter presenting potential as an alternative additive.

One important feature of corn distillers dried grains with solubles (DDGS) is its high leucine:lysine ratio, which can inhibit chicken growth by causing branched-chain amino acid (BCAA) antagonism. The current study was conducted to investigate the effects of BCAA imbalance of inclusion of DDGS and whether additional dietary valine and isoleucine could alleviate the negative effects in broilers. A total of 640 0-d-old male Cobb 500 broilers were allocated into 4 treatments with 8 replicates and reared until d 42. The four different dietary groups were as follows: 1) control (CON) group (corn-soybean meal-based diet); 2) 30% DDGS (30D) group (replacing soybean meal with 30% DDGS); 3) 30D + additional valine and isoleucine (30DB) group; and 4) the group of 30DB + additional valine and isoleucine to provide the same leucine:valine and leucine:isoleucine ratios as the CON group (30DBB). The analyzed leucine:lysine ratios of the CON group were 1.36/1.41/1.46 (starter/grower/finisher phase), whereas the average leucine:lysine ratios of the 30% DDGS groups were 1.61/1.70/1.78 (starter/grower/finisher phase). The 30% DDGS groups (30D, 30DB, and 30DBB) negatively affected body weight (BW) from d 7 to 42 and BW gain (BWG), feed intake, carcass weight, breast muscle weight, and jejunal and ileal villus height:crypt depth during the overall period (d 0 to 42) (P < 0.05). Furthermore, the 30% DDGS groups significantly altered expression levels of jejunal tight junction proteins, breast muscle mechanistic target of rapamycin (mTOR) pathway-related genes, BCAA catabolism genes, and AA transporters compared to the CON (P < 0.01). The 30% DDGS groups showed differences in beta-diversity indices compared to the CON group (P < 0.05). The 30DBB group showing the lowest d 21 and 42 BW and overall BWG had the largest differences compared to the CON group in most measurements. In conclusion, excessive replacement of soybean meal with DDGS can significantly increase leucine levels, which may negatively affect chicken growth. Additionally, inappropriate ratios of valine and isoleucine can further decrease growth performance.

Background: The intestinal tract, as the main place for nutrient digestion and absorption, is closely related to the health of livestock and poultry. Melatonin secreted by the pineal gland acts as an endocrine transport signaling molecule to regulate intestinal function. However, the effect on intestinal function after pineal removal is unclear.

Methods: We raised 24 chicks under 400-700 nm white light with or without pinealectomy for 21 days. We used electron microscopy, HE staining, PAS staining, immunohistochemistry, immunofluorescence staining and western blot to detect intestinal physical and to explore the effect of melatonin secreted by the pineal gland on the intestinal mucosa barrier function.

Results: The results showed that after pineal gland removal, the structure of the intestinal villi is severely damaged. Moreover, there was an obviously down-regulation in the villi length, the number of goblet cells and and its secretion of MUC2 protein, the expression level of tight junction proteins (Occludin and ZO-1) and lysozyme secreted by paneth cells, number of PCNA positive cells and macrophage, and an up-regualtion in crypt depth and apoptosis level after pinealectomy, suggesting pinealectomy-mediated melatonin level decrease damaged the intestinal physical, chemical and immune barriers.

Conclusion: Our findings provide new theoretical support for the future use of melatonin in intestinal development and new ideas about the relationship between endocrine hormone and intestinal physiology.

The impact of dietary lysozyme (LZ) supplementation on the growth and laying performance was investigated over 4 weeks of growing and 6 weeks of laying periods in two different plumage color (white and brown-feathered) Japanese quail varieties. For each variety, 240 birds were randomly assigned into four groups with four replicates for each group. The first group (control) was fed a basal non-supplemented diet (BD). Whereas the 2^nd, 3^rd, and 4^th received the BD supplemented with commercial LZ (CLZ) at 100 mg/kg diet, and natural LZ (NLZ) at 100 and 200 mg/kg diet, respectively. The main findings included significant increases in body weights and gains in the white-feathered quails supplemented with NLZ1 compared to the control and NLZ2. However, there were no significant differences in the case of brown-feathered quails in all LZ supplementations. Moreover, the different dietary LZ lowered FI in both quails with the lowest intake observed in the brown-feathered quails. Accordingly, enhanced FCR was reported in the CLZ groups for both quail varieties and in NLZ1 and NLZ2 for the white-feathered and brown-feathered quails, respectively. In both quail varieties, the NLZ2 significantly lowered serum creatinine and urea and increased albumen and globulin levels compared with other groups. Histologically, the best hepatic histological features were found in both quail' varieties fed the NLZ1-supplemented diet. Accompanying LZ-induced modulations in the expression levels of GHR, IGF-1, leptin, CCK, FAS, and ACC genes in both quail varieties were reported. Besides, both quail varieties in NLZ1& NLZ2 supplementation exhibited significant increases in hen day egg production, egg weight, egg mass, and hatchability percentages along with differences in external and internal egg qualities compared with LZ-free diet or CLZ. Therefore, NLZ could be used as an effective feed supplement to enhance the growth and egg performance of Japanese quail with caution being drawn to the supplementation dose about quail variety.

This study aims to conduct active surveillance of avian influenza in the southwestern Poyang Lake area of China and to analyze the changes in avian influenza prevalence in wholesale poultry markets and frozen fresh retail markets following the implementation of policies regulating frozen fresh poultry products. The type A avian influenza virus nucleic acids were detected using real-time reverse transcription polymerase chain reaction (real-time RT-PCR), and a triplex real-time RT-PCR assay kit specific for H5/H7/H9 RNA was utilized on the influenza A-positive samples to differentiate among the avian influenza virus subtypes. From October 2020 to June 2024, the positivity rate of the live poultry wholesale market was 59.2 %. The positivity rate of frozen fresh retail markets was 45.4 %. In August 2023, the H9 subtype had the highest positivity rate in both markets. However, after that, the rate of untyped positives began to rise, particularly in the live poultry wholesale market where the positivity rate of the H5 subtype also showed an increasing trend. Implementing a frozen fresh poultry products policy has effectively reduced the avian influenza positivity rate in frozen fresh retail markets over the first two years. However, the positivity rate showed a rebound trend in the last two years. The live poultry wholesale market may be the source of the spread of avian influenza in frozen fresh retail markets, so managing the live poultry wholesale market and surveillance avian influenza should be strengthened. Recent surveillance indicates a significant uptick in the positivity rates of the H5 subtype and untyped strains of avian influenza, underscoring the importance of continued vigilance and strengthened prevention and control measures.

Machine learning (ML) methods have rapidly developed in various theoretical and practical research areas, including predicting genomic breeding values for large livestock animals. However, few studies have investigated the application of ML in broiler breeding. In this study, seven different ML methods-support vector regression (SVR), random forest (RF), gradient boosting decision tree (GBDT), extreme gradient boosting (XGBoost), light gradient boosting machine (LightGBM), kernel ridge regression (KRR) and multilayer perceptron (MLP) were employed to predict the genomic breeding values of laying traits, growth and carcass traits in a yellow-feathered broiler breeding population. The results indicated that classic methods, such as GBLUP and Bayesian, achieved superior prediction accuracy compared to ML methods in five of the eight traits. For half-eviscerated weight (HEW), ML methods showed an average improvement of 54.4% over GBLUP and Bayesian methods. Among the ML methods, SVR, RF, GBDT, and XGBoost exhibited improvements exceeding 60%, with respective values of 61.3%, 61.0%, 60.4%, and 60.7%; while MLP improved by 54.4% and LightGBM by 53.7%, KRR had the lowest improvement at 29.4%. For eviscerated weight (EW), ML methods still outperformed GBLUP and Bayesian methods. MLP gained the largest improvement at 19.0%, while SVR, RF, GBDT, XGBoost, LightGBM, and KRR improved by 15.0%, 16.5%, 9.5%, 7.0%, 1.6%, and 15.9%, respectively. Compared to default hyperparameters, the average improvement of ML methods with tuned hyperparameters was 34.0%, 32.9%, 27.0%, 19.3%, 26.8%, 13.2%, 18.9%, and 46.3%, respectively. The prediction accuracy of above algorithms could be optimized using genome-wide association study (GWAS) to select subsets of significant SNPs. This work provides valuable insights into genomic prediction, aiding genetic breeding in broilers.