Poultry Science最新文献

This study aims to investigate the effects of different relative humidity (RH) during 4-21d of Beijing ducks on their condition at 42 d. A total of 48 Pekin duck were randomly allotted into 4 treatments (A:RH60 %, B:RH67 %,C:RH74 %,D:RH81 %), each having 3 replicates of 4 ducks. Different humidity treatments were applied from 4 to 21 days. At 42 d, there were no significant differences (P > 0.05) in body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) among the 4 groups. Oblique body length in D was significantly higher than that in A (P < 0.05). Compared with A, the chest depth of the other groups was significantly increased, and the abdominal fat weight of B and C was significantly increased (p < 0.05). Liver weight and liver index in C and D significantly higher than that in B (p < 0.05). Abdominal fat ratio in B was significantly higher than that in A (P < 0.05). Cholesterol (CHOL) in D was significantly higher than that in A and C (P < 0.05), triglyceride (TG) in C was significantly higher than that in A and B (P < 0.05), and low-density lipoprotein cholesterol (LDL-C) in B was significantly higher than that in A, C, and D (P < 0.05). pH in B was significantly higher than that in A (P < 0.05), brightness (L*) in A was significantly higher than that in B and C (P < 0.05), redness (a*) in B and C was significantly higher than that in A and D (P < 0.05), and yellowness (b*) in C was significantly lower than that in A and D (P < 0.05).The results indicate that the RH of environment during the brooding period has no impact on duck production performance but induces some oxidative stress damage and changes in meat quality. Additionally, ducks subjected to different RH treatments during the brooding period exhibit varying adaptability to the same environment as they mature.

This study investigated the effects of multi-enzyme supplementation on various aspects of laying hens, including laying performance, egg quality, intestinal health and digestive function. In total, 384 Jingfen No.6 laying hens at 65-week-age were randomly assigned to four distinct dietary treatments: a basal diet (CON), CON supplemented with 150 g/t multi-enzyme (T1), CON with 300 g/t multi-enzyme (T2), and 600 g/t multi-enzyme (T3). A significant linear (P = 0.044) and quadratic (P = 0.014) increase was observed in the laying rate, while the feed/egg ratio exhibited a linear (P = 0.001) and quadratic (P < 0.001) decrease with increasing multi-enzyme supplementation. Additionally, linear (P < 0.05) and quadratic (P < 0.05) increases were observed in yolk rate and haugh unit with increasing levels of multi-enzyme supplementation. The trypsin activity in the duodenum and crude protein digestibility showed linear (P < 0.05) and quadratic (P < 0.05) increase with the addition of multi-enzyme. Furthermore, lipase and amylase activities in the duodenum increased quadratically (P = 0.041) and linearly (P = 0.040), respectively. Both jejunal and ileal digesta viscosities showed linear (P < 0.05) and quadratic (P < 0.05) decrease with the increasing addition of multi-enzyme. Moreover, multi-enzyme supplementation significantly increased (P < 0.05) the number of goblet cells in the intestinal of the treatment groups. The mRNA expression of Occludin-1, mucin 2 (MUC-2), large neutral amino acids transporter small subunit 1 (LAT-1) in the jejunum were significantly increased (P < 0.05) in the treatment groups (T1, T2 and T3) compared to the CON group. Additionally, the mRNA expression of solute carrier family 6-member 19 (B⁰AT-1) and large neutral amino acids transporter small subunit 4 (LAT-4) were significantly evaluated (P < 0.05) in the T2 and T3 groups, respectively. In conclusion, multi-enzyme supplementation enhanced digestive enzyme activities and intestinal barrier function, reduced intestinal digesta viscosity, and regulated mRNA expression of intestinal amino acid and lipid transporter genes, thereby improving crude protein digestibility and positively affecting laying performance and egg quality in hens.

The growing phase of laying hens is crucial for growth and development due to its direct impact on their productivity during laying phase. During initial growth phase, intestinal tract undergoes rapid development which requires plenty of nutrients to help laying hens grow and mature. This study investigated the effect of Alanyl-Glutamine (Aln-Gln) levels on growth performance, ileal morphology and transcriptomic analysis of growing Hy-line brown hens. A total of 480 day old Hy-line brown chicks having similar body weight (BW) were randomly divided to be fed diets having 0%, 0.1%, 0.2% and 0.3% Aln-Gln for 6-wks (8 replicates/group, 15 birds/replicate). One bird from every pen was slaughtered and morphological parameters of ileum were evaluated. Results taken on day 42 revealed an improved average daily gain (ADG), final body weight (FBW) and feed-to-gain ratio (F/G) in the birds that consumed 0.2% and 0.3% Aln-Gln supplemented diet (P < 0.05). Ileal morphological assays showed that villus height, villus width and villus to crypts ratio (V/C) were significantly increased at 42 days of age in birds fed diets with 0.2% Aln-Gln (P<0.05). The RNA sequencing (RNA-Seq) was executed to identify differentially expressed genes (DEGs) among groups that found 2265 DEGs (1256 up-regulated; 1009 down-regulated) in ileum tissue. According to the Kyoto Encyclopedia of Genes (KEGG) and Genomic Pathway Enrichment Analysis, majority of DEGs indicated change in metabolic pathways. Genes related to growth factors, intestinal morphology and protein metabolism were up-regulated in test groups as compared to control group. In conclusion, addition of Aln-Gln to the diet improved growth performance and ileum development in growing hens; transcriptomic analysis revealed up-regulation of genes related to growth and intestinal morphology.

The excessive accumulation of abdominal fat in chickens has resulted in a reduction in both the feed conversion efficiency and the slaughter yield. To elucidate the regulatory mechanisms and metabolic pathways affecting abdominal fat deposition in the context of broiler breeding, a cohort of 400 Qingyuan partridge chickens with varying abdominal fat deposition was established. Whole transcriptome sequencing analyses were conducted on the duodenum of 20 representative chickens to ascertain the regulatory networks at this vital digestive and absorptive organ. Consequently, 116 differentially expressed genes were identified, exhibiting a trend of increasing or decreasing expression in correlation with the accumulation of abdominal fat. A total of 36 DEmRNAs, 170 DElncRNAs, 92 DEcircRNAs and 88 DEmiRNAs were identified as differentially expressed between chickens with extremely high and low abdominal fat deposition. The functional enrichment analyses demonstrated that the differentially expressed RNA in the duodenum were involved in the regulation of chicken abdominal fat deposition by mediating a series of metabolic pathways, including the Wnt signaling pathway, the PPAR signaling pathway, the Hippo signaling pathway, the FoxO signaling pathway, the MAPK signaling pathway and other signaling pathways that are involved in fatty acid metabolism and degradation. The construction of putative interaction pairs led to the suggestion of two lncRNA-miRNA-mRNA ceRNA networks comprising two mRNAs, two miRNAs, and 29 lncRNAs, as well as two circRNA-lncRNA-miRNA-mRNA ceRNA networks comprising 26 mRNAs, 12 miRNAs, 17 lncRNAs, and nine circRNAs, as core regulatory networks in the duodenum affecting chicken abdominal fat deposition. The aforementioned genes including TMEM150C, REXO1, PIK3C2G, ppp1cb, PARP12, SERPINE2, LRAT, CYP1A1, INSR and APOA4, were proposed as candidate genes, while the miRNAs, including miR-107-y, miR-22-y, miR-25-y, miR-2404-x and miR-16-x, as well as lncRNAs such as ENSGALT00000100291, TCONS_00063508, TCONS_00061201 and TCONS_00079402 were the candidate regulators associated with chicken abdominal fat deposition. The findings of this study provide a theoretical foundation for the molecular mechanisms of mRNAs and non-coding RNAs in duodenal tissues on abdominal fat deposition in chickens.

Intestinal dysbacteriosis is increasing in broilers due to the reduced use of antibiotics in feed. This study tested the effect of daily waterline administration of a dual-strain probiotic comprising Lactobacillus acidophilus AG01 and Bifidobacterium animalis subspecies lactis AG02, on growth performance and intestinal health during a 3-step microbial challenge. In total, 900 Ross 308 males were assigned to 36 floor pens (25 birds/pen, 12 pens/treatment) in a completely randomized design. Birds were fed a corn, wheat and soybean-meal based diet. Diets were formulated in 3 phases (starter: 1 to 10; grower: 11 to 24; finisher: 25 to 42 d of age). Treatments comprised a non-challenged control (NC), challenged control (CC), and the CC supplemented with 1 × 10⁸ colony forming units (CFU)/bird/day of the probiotic (CC+Probiotic). The challenge comprised 1 × 10⁸ CFU/bird of Avian Pathogenic Escherichia coli on d 7, 4,000 oocysts/bird of Eimeria on d 15 and 1 × 10⁹ CFU/bird of C. perfringens on d 18, 19 and 20. Growth performance was monitored over 42 d, blood samples, and digesta were collected and intestinal dysbacteriosis scoring was performed. Compared to NC birds, CC birds exhibited reduced BW (all phases), reduced feed intake (starter and grower phase), increased FCR (grower phase and overall; P < 0.05), reduced ileal lactic acid bacteria concentrations (d 24 and 42), and increased cecal E. coli (d 24; P < 0.05). Compared to CC birds, CC+Probiotic birds exhibited increased BW, BW gain and feed intake during grower phase (P < 0.05), increased ileal lactic acid bacteria at d 24 and 42 and reduced ileal C. perfringens at d 24, increased mucosal secretory IgA and reduced serum alpha-1-acid-glycoprotein at d 42. The overall growth performance of CC+Probiotic birds was equivalent to NC birds. These results confirm the efficacy of the dual strain probiotic for mitigating the negative effects of a multi-microbial challenge, improving gut health and growth performance in commercial broilers under dysbacteriosis challenge.

Antibiotics have been used for a long time as growth promoters in the poultry industry for growth and health benefits. However, recent studies reflected little, no, or negative impacts of using antibiotics for growth promotion purposes. This study was designed to examine the overall effect of antibiotic supplementation on the feed conversion ratio (FCR) in broiler chickens as a performance indicator and assess different covariates for explaining heterogeneity in response to the use of antibiotics as growth promoters. In this regard, FCRs obtained from articles that compared diets with and without antibiotics for broiler chickens were extracted from electronic databases (PubMed, Web of Science, and Google Scholar) as per PRISMA guidelines. The database comprised 42 scientific articles containing 74 experiments totaling 19,562 chickens. A basic meta-analysis and subgroup analysis were performed to assess the overall impact of antibiotic growth promoters (AGPs) on FCR of broiler chickens while a meta-regression analysis was used to assess different covariates (breed, antibiotic dose, location, time, presence of anticoccidial in the feed, antibiotic type, and housing type) to explain variations in true effect size of the studies. The basic meta-analysis of these studies revealed an overall improvement in FCR by 2.8 % (p < 0.05) due to addition of AGPs than the control group with the confidence interval range from 1.3 to 4.3 % and the prediction interval ranging between -10 and 16 %. The covariates, including breed, dose and location, provided the optimum model fit and explained 53 % of variations in the FCR across different studies. In summary, an overall marginal improvement has been observed in mean FCR of broiler chickens along with a wide range of variations in response to use of AGPs. The variations in true effects among these studies are subject to several confounding effects, particularly breed, dose and location. Considering the marginal positive effect of antibiotic usage in chicken performance, we recommend against using of AGP.

The rearing environment for pullets should mirror their later production environment as closely as possible. However, existing perch space recommendations are based on data for laying hens rather than pullets. This study explores the impact of perch space allowances on the welfare of Canadian laying strain pullets raised to 18 wk. Two trials were conducted with 1,032 Lohmann Brown-Lite (LB) and LSL-Lite (LW) pullets each. A randomized complete block (trial) design was used with a 4 (perch space) × 2 (strain) factorial arrangement. Birds were raised in 16 floor pens (3 × 3 m each; 897.67 cm² per bird). Wooden perches were provided from d 1, allowing 6, 9, 12, or 15 cm perch space per pullet. Data were tested for normality, and log+1 transformed if necessary. Significance was declared at P≤0.05. Data were collected for basic health and functioning (body weight, mortality, pullet width, keel bone damage, and tibia bone parameters), affective states (comb damage, heterophil-to-lymphocyte (H/L) ratios, and behavior), and natural living (perch usage and jumping success). Perch space did not affect mortality, keel bone damage, tibia breaking strength, comb damage, or H/L ratios. At 16 and 18 wk, LB body weight slightly increased while the LW body weight decreased with increasing perch space (P=0.05 and 0.02). At 3 wk, pullets spent a higher percentage of time wing flapping on the perch when provided 15 cm compared to 6 cm (P=0.04). During the scotoperiod at 18 wk, a higher percentage of birds perched with 12 and 15 cm perch space than 6 cm (P<0.01). Pullet width at 18 wk was 12.52 cm (sitting) and 11.66 cm (standing) for the LB and 13.85 cm (sitting) and 12.94 cm (standing) for the LW. Overall, perch space allowance had minor effects on the measured welfare indicators. Based on pullet width, a minimum of 12.5 cm for LW and 13.9 cm for LB pullets should be provided to allow all pullets to sit on the perch simultaneously.

Fowl adenovirus serotype 4 (FAdV-4) is the main causative agent of hydropericardium hepatitis syndrome (HHS), which has resulted in huge economic losses to the poultry industry in recent years. Hence, a rapid and simple visual detection method is needed for identification of FAdV-4. In this study, three multienzyme isothermal rapid amplification (MIRA) assays, basic MIRA, MIRA-qPCR and MIRA-LFD were developed for detection of FAdV-4. The amplification primers and reaction conditions were optimized, and the specificity and sensitivity of the assays were evaluated. The MIRA assays were specific for FAdV-4 with no cross-reaction with novel goose astrovirus, H9 subtype avian influenza virus, duck enteritis virus, Muscovy duck reovirus, or duck circovirus. The basic MIRA assay required only one primer pair and the reaction can be completed within 30 min at 36 °C. The MIRA-qPCR and MIRA-LFD assays were completed in 20 min with a minimum detection limit of 1 × 10¹ copies/μL and 1 × 10² copies/μL, respectively. The results of the MIRA-LFD assay can be observed directly with the naked eye, omitting the need for specialized instruments. The positive rate of three proposed MIRA assays were consistent with that of the conventional PCR assay. The MIRA assays are simple, rapid, and effective diagnostic tools for field detection of FAdV-4.

The differences in metabolites between fresh egg yolk (FEY), spray-dried egg yolk powder (SEY), and stored egg yolk powder (S-SEY) were quantitatively compared through metabolomic analysis. Total of 1004 metabolites were identified in the three groups of egg yolk samples. In pairwise group analysis, 242 differential metabolites were identified in FEY and SEY, 311 differential metabolites were identified in FEY and S-SEY, and 157 differential metabolites were identified in SEY and S-SEY. The analysis of differential metabolites with the highest abundance showed that amino acids, carbohydrates and lipids in FEY would undergo oxidation reactions after spray drying and storage and thus led to significant changes in the type and abundance of metabolites. The representative differential metabolites were then screened out for judging the freshness of egg yolk powder. Therefore, the results are highly important for evaluating the quality of egg yolk powder and provide important information for understanding the nutritional changes of egg yolk after spray drying and storage.