Nutritional synergy: optimizing growth in Siruvidai chicken via diverse dietary energy and protein strategies and gene expression analysis - brooder phase.

Nutrient supply regulates overall body growth directly or indirectly through its influence on regulatory factors optimizing nutrient requirements becomes crucial before embarking on genetic improvements. Hence this study addresses this gap by evaluating the effect of feeding varying energy and crude protein levels on growth performance and gene expression related to the growth of indigenous Siruvidai chicken from 0 to 12 weeks. A 360-day-old straight-run Siruvidai chick were randomly distributed into six experimental groups with three replicates of each 20 chicks. The birds were fed corn-soy-based diets formulated with two levels of energy (2500 and 2700 kcal ME/kg) each with three levels of crude protein (16, 18, and 20%) during the brooder stage (0-12 weeks) in 2 × 3 factorial design. Results revealed that there was no significant effect on the energy and protein interaction levels on average feed intake, body weight gain and feed conversion ratio in Siruvidai chicken at 12 weeks. The results showed significantly (P < 0.05) lower feed intake in 18% protein fed groups and significantly (P < 0.01) lower feed intake in higher energy 2700 kcal ME/kg fed groups. A better feed conversion ratio (4.06 and 4.21) was observed on the effect of protein levels in bird diets with 18% and 20% protein fed groups. The Growth Hormone (GH) and Myostatin (MSTN) gene expression were significantly (P < 0.01) higher in 16% CP and 2500 kcal ME/kg in hepatic tissue. The high protein and low energy diet up-regulated the Insulin-like Growth Factor-1 (IGF-1) gene expression in hepatic tissue. The study concluded that Siruvidai chicken fed with 18% crude protein and 2500 kcal ME/kg is optimum for 0-12 weeks of age.

Ontogeny of hepatic metabolism in two broiler lines divergently selected for the ultimate pH of the Pectoralis major muscle.

BACKGROUND: Nutrient availability during early stages of development (embryogenesis and the first week post-hatch) can have long-term effects on physiological functions and bird metabolism. The embryo develops in a closed structure and depends entirely on the nutrients and energy available in the egg. The aim of this study was to describe the ontogeny of pathways governing hepatic metabolism that mediates many physiological functions in the pHu + and pHu- chicken lines, which are divergently selected for the ultimate pH of meat, a proxy for muscle glycogen stores, and which differ in the nutrient content and composition of eggs. RESULTS: We identified eight clusters of genes showing a common pattern of expression between embryonic day 12 (E12) and day 8 (D8) post-hatch. These clusters were not representative of a specific metabolic pathway or function. On E12 and E14, the majority of genes differentially expressed between the pHu + and pHu- lines were overexpressed in the pHu + line. Conversely, the majority of genes differentially expressed from E18 were overexpressed in the pHu- line. During the metabolic shift at E18, there was a decrease in the expression of genes linked to several metabolic functions (e.g. protein synthesis, autophagy and mitochondrial activity). At hatching (D0), there were two distinct groups of pHu + chicks based on hierarchical clustering; these groups also differed in liver weight and serum parameters (e.g. triglyceride content and creatine kinase activity). At D0 and D8, there was a sex effect for several metabolic pathways. Metabolism appeared to be more active and oriented towards protein synthesis (RPS6) and fatty acid ß-oxidation (ACAA2, ACOX1) in males than in females. In comparison, the genes overexpressed in females were related to carbohydrate metabolism (SLC2A1, SLC2A12, FoxO1, PHKA2, PHKB, PRKAB2 and GYS2). CONCLUSIONS: Our study provides the first detailed description of the evolution of different hepatic metabolic pathways during the early development of embryos and post-hatching chicks. We found a metabolic orientation for the pHu + line towards proteolysis, glycogen degradation, ATP synthesis and autophagy, likely in response to a higher energy requirement compared with pHu- embryos. The metabolic orientations specific to the pHu + and pHu- lines are established very early, probably in relation with their different genetic background and available nutrients.

Effects of high dietary inclusion of Arthrospira platensis, either extruded or supplemented with a super-dosing multi-enzyme mixture, on broiler growth performance and major meat quality parameters.

BACKGROUND: This investigation assessed the effects of high dietary inclusion of Spirulina (Arthrospira platensis) on broiler chicken growth performance, meat quality and nutritional attributes. For this, 120 male broiler chicks were housed in 40 battery brooders (three birds per brooder). Initially, for 14 days, a standard corn and soybean meal diet was administered. Subsequently, from days 14 to 35, chicks were assigned to one of the four dietary treatments (n = 10 per treatment): (1) control diet (CTR); (2) diet with 15% Spirulina (SP); (3) diet with 15% extruded Spirulina (SPE); and (4) diet with 15% Spirulina plus a super-dosing enzymes supplement (0.20% pancreatin extract and 0.01% lysozyme) (SPM). RESULTS: Throughout the experimental period, both SP and SPM diets resulted in decreased final body weight and body weight gain compared to control (p < 0.001), with the SPE diet showing comparable results to CTR. The SPE diet prompted an increase in average daily feed intake (p = 0.026). However, all microalga treatments increased the feed conversion ratio compared to CTR. Dietary inclusion of Spirulina notably increased intestinal content viscosity (p < 0.010), which was mitigated by the SPM diet. Spirulina supplementation led to lower pH levels in breast meat 24 h post-mortem and heightened the b* colour value in both breast and thigh meats (p < 0.010). Furthermore, Spirulina contributed to an increased accumulation of total carotenoids, n-3 polyunsaturated fatty acids (PUFA), and saturated fatty acids (SFA), while diminishing n-6 PUFA, thus altering the n-6/n-3 and PUFA/SFA ratios favourably (p < 0.001). However, it also reduced zinc concentration in breast meat (p < 0.001). CONCLUSIONS: The findings indicate that high Spirulina levels in broiler diets impair growth due to increased intestinal viscosity, and that extrusion pre-treatment mitigates this effect. Despite reducing digesta viscosity, a super-dosing enzyme mix did not improve growth. Data also indicates that Spirulina enriches meat with antioxidants and n-3 PUFA but reduces α-tocopherol and increases saturated fats. Reduced zinc content in meat suggests the need for Spirulina biofortification to maintain its nutritional value.

Efficacy of supplementing Aspergillus awamori in enhancing growth performance, gut microbiota, digestibility, immunity, and antioxidant activity of heat-stressed broiler chickens fed diets containing olive pulp.

BACKGROUND: Gut microbes play a significant role in digestion, developing immunity, and intestinal health. Therefore, direct-fed microbials are used to modify gut microbiota, maintain a healthy digestive system, enhance immunity, and promote the broilers' performance. In addition, it has a role in improving the utilization of unconventional feed ingredients (olive pulp, OP). This study provides the potential role of Aspergillus awamori in enhancing gut microbial content, nutrient utilization, growth performance, and antioxidative status in heat-stressed broiler chickens fed diets containing olive pulp. METHODS: Three hundred chicks (Ross 308; one day old) were divided into four treatment groups (75 chick/ group) randomly, as follows; CON: chicks fed a basal diet based on corn and soybean meal, OP10: chicks fed a diet containing 10% OP, OA1: chicks fed a diet containing OP with A. awamori at 100 mg per kg, OA2: chicks fed a diet containing OP with A. awamori at 200 mg per kg. RESULTS: Adding A. awamori to the broiler diet that contains OP had a positive effect on productive performance via enhancing nutrition digestibility, body weight gain, feed conversion ratio, and carcass characteristics. A. awamori supplementation had a positive impact on immune responses by increasing serum immunoglobulin G and the relative weight of bursa of Fabricius (P < 0.05) compared to the other groups. Chickens fed A. awamori showed a noticeable improvement in the oxidative status through the increase in the level of serum superoxide dismutase, and glutathione peroxidase, and the decrease in the level of malondialdehyde. Feeding A. awamori also modified the intestinal microbial content by increasing the population of Lactobacillus (P < 0.05). CONCLUSIONS: Our study indicated that adding 200 mg A. awamori reduced the negative effect of heat stress by modifying the microbial content of the intestine, immune response, and enhancing feed utilization, thus improving broiler performance, as well as, improving the nutritional value of the olive pulp. Therefore, adding A. awamori to the OP diet can be effectively used in heat-stressed broiler diets.

Effects of abrupt and gradual light/dark switching on growth performance, behavior, villus development, meat characteristics, and immunity of broilers.

The aim of this study is to determine the effect of abrupt and gradual light/dark switching on growth performance, behavior, villus development, meat characteristics, and immunity of broilers. A total of 270 daily male broiler chicks were used in the experiment. The study comprised three groups based on whether the transitions between light and dark periods were abrupt or gradual. No significant differences were observed among the examined groups in terms of body weight, weight gain, mortality rate, feeding, pecking, relaxing, and feather preening behaviors, carcass, and breast meat quality characteristics. Total body weight gain, total feed consumption, total feed utilization ratio, and mortality rates of broilers during the 6-week fattening period did not differ compared to the abrupt transition. Broilers in the group with gradual transition exhibited less movement, more sitting, and sleeping behaviors. It was determined that the IgG was higher in the gradual transition group. The transitions between light and dark periods influenced the characteristics of thigh meat. Villus height and crypt depth were higher in the group where a 1-h gradual transition was applied. As a conclusion, gradual transition is more appropriate in broiler rearing.

Effects of dietary multienzymes on the growth performance, digestive enzyme activity, nutrient digestibility, excreta noxious gas emission, and nutrient transporter gene expression in white feather broilers.

Adding multienzymes to poultry feed rations is recognized as a nutritional strategy aimed at improving poultry performance and health status. Nonetheless, some literatures present an ongoing debate about the extent of multienzymes beneficial impact on poultry growth performance. This study aimed to explore the impacts of dietary multienzyme supplementation on broilers, focusing specifically on growth performance, carcass characteristics, apparent nutrient digestibility, excreta noxious gas emission, and intestinal nutrient transporter gene expression. A total of 3,200 broilers were randomly assigned to five groups (eight replicates per treatment group) and treated with the following: normal control (CON), CON + 100 g/t multienzyme (ME100), CON + 150 g/t multienzyme (ME150), CON + 200 g/t multienzyme (ME200), and CON + 250 g/t multienzyme (ME250). Supplementing with multienzymes significantly influenced the feed conversion rate (linear, P = 0.007; quadratic, P = 0.024) and the European broiler index (linear, P = 0.004; quadratic, P = 0.016) in broilers. Dietary multienzymes significantly influenced apparent metabolizable energy (quadratic, P = 0.015) and neutral detergent fiber (quadratic, P < 0.001). Moreover, multienzyme supplementation in the diet also decreased the emission of ammonia (linear, P = 0.001; quadratic, P = 0.006) and hydrogen sulfide (quadratic, P = 0.006) in the excreta. In addition, dietary multi-enzyme notably elevated (P < 0.05) the mRNA expression of nutrient transporter genes, including peptide transporter 1 (PePT1), Na-dependent neutral amino acid transporter (B0AT), glucose transporter 2 (GLUT2), and fatty acid binding protein1 (FABP1). These findings suggest that dietary supplementation with multienzymes can improve the efficiency of feed utilization, and the digestion and absorption of nutrients and reduce excreta gas emission. Furthermore, this study provides a theoretical basis for advancing the use of multienzymes in broiler production.

Multienzyme additives are increasingly used in animal feed, primarily to enhance growth performance and nutrient digestibility. This study focused on the effects of multienzyme additives (xylanase, mannanase, cellulase, arabinofuranosidase, ferulic acid esterase, amylase, and protease) on various aspects of broilers, including growth performance, carcass characteristics, digestive enzyme activities, apparent nutrient digestibility, excreta noxious gas emission, and intestinal nutrient transporter gene expression. The inclusion of multienzymes in the diet was found to significantly increase the weight of breast muscle in broilers. Additionally, it led to a notable decrease in the viscosity of the fecal and jejunal digesta. Furthermore, the present study revealed an increase in the mRNA expression of key nutrient transporters­peptide transporter 1 (PePT1), Na-dependent neutral amino acid transporter (B0AT), and fatty acid binding protein 1 (FABP1), in the intestine of broilers. These findings indicate that dietary multienzymes enhance the efficiency of feed nutrient digestion and absorption in broilers.

Genetic parameter estimation and molecular foundation of chicken beak shape.

The bird beak is mainly functioned as feeding and attacking, and its shape has extremely important significance for survival and reproduction. In chickens, since beak shape could lead to some disadvantages including pecking and waste of feed, it is important to understand the inheritance of chicken beak shape. In the present study, we firstly established 4 indicators to describe the chicken beak shapes, including upper beak length (UL), lower beak length (LL), distance between upper and lower beak tips (DB) and upper beak curvature (BC). And then, we measured the 4 beak shape indicators as well as some production traits including body weight (BW), shank length (SL), egg weight (EW), eggshell strength (ES) of a layer breed, Rhode Island Red (RIR), in order to estimate genetic parameters of chicken beak shape. The heritabilities of UL and LL were 0.41 and 0.37, and the heritabilities of DB and BC were 0.22 and 0.21, indicating that beak shape was a highly or mediumly heritable. There were significant positive genetic and phenotypic correlations among UL, LL, and DB. And UL was positively correlated with body weight (BW18) and shank length (SL18) at 18 weeks of age in genetics, and DB was positively correlated with BC in terms of genetics and phenotype. We also found that layers of chicken cages played a role on beak shape, which could be attributed to the difference of lightness in different cage layers. By a genome-wide association study (GWAS) for the chicken UL, we identified 9 significant candidate genes associated with UL in RIR. For the variants with low minor allele frequencies (MAF <0.01) and outside of high linkage disequilibrium (LD) regions, we also conducted rare variant association studies (RVA) and GWAS to find the association between genotype and phenotype. We also analyzed transcriptomic data from multiple tissues of chicken embryos and revealed that all of the 9 genes were highly expressed in beak of chicken embryos, indicating their potential function for beak development. Our results provided the genetic foundation of chicken beak shape, which could help chicken breeding on beak related traits.

Complex genetic architecture of the chicken Growth1 QTL region.

The genetic complexity of polygenic traits represents a captivating and intricate facet of biological inheritance. Unlike Mendelian traits controlled by a single gene, polygenic traits are influenced by multiple genetic loci, each exerting a modest effect on the trait. This cumulative impact of numerous genes, interactions among them, environmental factors, and epigenetic modifications results in a multifaceted architecture of genetic contributions to complex traits. Given the well-characterized genome, diverse traits, and range of genetic resources, chicken (Gallus gallus) was employed as a model organism to dissect the intricate genetic makeup of a previously identified major Quantitative Trait Loci (QTL) for body weight on chromosome 1. A multigenerational advanced intercross line (AIL) of 3215 chickens whose genomes had been sequenced to an average of 0.4x was analyzed using genome-wide association study (GWAS) and variance-heterogeneity GWAS (vGWAS) to identify markers associated with 8-week body weight. Additionally, epistatic interactions were studied using the natural and orthogonal interaction (NOIA) model. Six genetic modules, two from GWAS and four from vGWAS, were strongly associated with the studied trait. We found evidence of both additive- and non-additive interactions between these modules and constructed a putative local epistasis network for the region. Our screens for functional alleles revealed a missense variant in the gene ribonuclease H2 subunit B (RNASEH2B), which has previously been associated with growth-related traits in chickens and Darwin's finches. In addition, one of the most strongly associated SNPs identified is located in a non-coding region upstream of the long non-coding RNA, ENSGALG00000053256, previously suggested as a candidate gene for regulating chicken body weight. By studying large numbers of individuals from a family material using approaches to capture both additive and non-additive effects, this study advances our understanding of genetic complexities in a highly polygenic trait and has practical implications for poultry breeding and agriculture.

Impact of dichromatic lighted incubation on hatching result and post-hatch performance of broiler chickens.

This study was planned to evaluate the impact of dichromatic lights during incubation on the hatching and post-hatch performance of broiler chickens. A total of 500 eggs of broiler breeder (Ross 308; Age 44 weeks) were evenly divided according to a completely randomized design into 4 treatments having 5 replicates and 25 eggs each. Treatments consisted of dichromatic lights Blue + Red (BR), Green + Red (GR) and Green + Blue (GB) provided at an intensity of 250 lx for 12 h a day along with a Dark (D) environment. After hatching 200 chicks (50 from each respective light group) were divided into 4 treatments with 5 replicates each having 10 chicks. Results indicated a higher embryo index (13.12%) in the GR group on the 12th day of incubation; while an ideal hatch window was observed in GR and GB (98.18% and 96.00% hatched chicks) lighting groups. In hatching traits, higher hatchability (86.15) and hatch of fertile (93.85) percentages were observed in GR lighting followed by GB, BR and Dark treatment groups; while dead-in shell embryos were lowest in the GR group. In growth performance, higher feed intake (513.20 g) and body weight (479.20 g) were observed in the GB group followed by GR, BR and dark group; and feed conversion ratio (FCR) was better in the GR group (1.06). In welfare parameters, improved physical asymmetry (0.90 mm) and tonic immobility (54.40 s) were measured in the GR group followed by GB, BR and the dark group. It was concluded that under experimental conditions when broiler breeder eggs are provided with GR lighting during incubation, it can help to improve hatchability, growth performance and welfare traits in chicks.

Relative biological efficacy of methionine hydroxy analogue-free acid compared to dl-methionine in the broiler chickens.

BACKGROUND: In the broiler's diets based on corn-soya bean meal, methionine (Met) and cystine (Cys), known as sulphur amino acids (SAAs), are the first limiting indispensable amino acids because of their limited presence, which are supplemented with different synthetic sources. Evaluation of the biological effectiveness of these sources can be important in their correct replacement, especially in the starter and growth diets. OBJECTIVES: The current study was done to assess the relative biological efficacy (RBE) of liquid Met hydroxy analogue-free acid (MHA-FA) in comparison with dl-Met (dl-Met) based on broiler performance traits at different levels of digestible SAA in the 1-11 (starter) and 11-25 (grower) days of age periods. METHODS: Two experiments were developed with treatments consisting of a basal diet without Met addition that met the nutrient and energy requirements of broilers with the exception of SAAs (Met + Cys) and five increasing Met doses for both sources (dl-Met and/or MHA-FA), resulting in digestible SAA concentrations from 0.62% to 1.02% of diet in the starter period (Trial 1) and 0.59% to 0.94% of diet in the grower period (Trial 2). The multi-linear regression model and slope ratio method were employed to calculate the RBE of MHA-FA compared with dl-Met for measured variables. RESULTS: In both experiments, the results obtained during the starter and grower periods with the different Met supplementations show significant growth responses to digestible SAAs levels. By increasing dietary dl-Met and/or MHA-FA levels, the growth performance traits and immune responses were improved (quadratic; p < 0.05). The RBE of MHA-FA compared to dl-Met on an equimolar basis was estimated 66%-89% (59%-79% on a weight-to-weight basis). CONCLUSIONS: It is concluded that the RBE of MHA-FA in comparison with dl-Met depends on broiler chicken age and what attribute is being evaluated.

Tibia properties in broilers raised on their own commercial diets with different growth rates and sex during a 10-week rearing period.

BACKGROUND: Genetic selection applied to broilers results in fast growth and an increase in meat yield. However, this situation causes welfare problems in broilers. OBJECTIVES: The aim of this study is to determine the weekly changes in the tibia characteristics in broilers raised on their own commercial diets. METHODS: In the study, 168 (84 female and 84 male) slow-growing (Hubbard-Isa Red JA) and 168 (84 female and 84 male) fast-growing (Ross-308) day-old broiler chicks were used. Six broilers from each genotype and sex group were weighed weekly and slaughtered to determine the tibia properties during the 10-week fattening period. RESULTS: Fast-growing broilers had higher tibia weight and longer length, diaphysis diameter and medullary canal diameter than those of slow-growing broilers at the same age. In fast-growing genotypes, the cortical index was low only in the 2nd week, and Robusticity and Seedor indices were observed to be better throughout the whole fattening. The ash content of the total tibia in the fast-growing broilers was higher in all of the examined weeks except the 4th week and the 9th week of fattening than that in the slow-growing broilers. Although the amount of ash per unit body weight in the 1st week of fattening was higher in fast-growing broilers, this situation reversed after the 4th week. The level of all minerals examined in total tibia weight is high in fast-growing broilers, and they differed according to the fattening period. CONCLUSIONS: When comparing tibia characteristics of two different genotypes fed their own commercial diets, the tibia structure was found to be stronger in fast-growing broilers compared to other genotypes at the same age, but slow-growing broilers were more prominent in terms of body weight. It was observed that the mineral density was higher in male broilers, except in the 1st week.

An investigation into the influence of fermented cottonseed meal on the productive performance, egg quality, and gut health in laying hens.

The present study investigates the effects of replacing soybean meal (SBM) with either cottonseed meal (CSM) or fermented cottonseed meal (FCSM) on the productive performance, egg quality, blood biochemistry parameters, gut bacterial population, and small intestinal morphology of laying hens. A total of 648 Hy-Line W36 laying hens aged 40 weeks were randomly assigned to 9 treatments, with 6 replicates each and 12 birds per replicate. The feeding trial lasted 12 weeks. The treatments consisted of a control diet based on corn and SBM, as well as 8 experimental diets in which 7.5, 15, 22.5, and 30% of the SBM in the control diet was replaced with either CSM or FCSM. Laying hens fed diets with different levels of FCSM had higher egg production and egg mass than those fed with CSM diets at weeks 46 to 51 (P < 0.05). Diets containing FCSM also significantly improved the feed conversion ratio at weeks 40 to 45 and 46 to 51 (P < 0.05). Eggshell strength was significantly greater in birds fed diets containing FCSM than those fed other dietary treatments at 51 weeks of age (P < 0.05). Hens fed diets containing FCSM had higher calcium and lower cholesterol in serum than those on other diets (P < 0.05). Replacing SBM with FCSM decreased the egg yolk cholesterol content (P < 0.05). Additionally, feeding diets containing different levels of FCSM increased villus height and villus height to crypt depth in the jejunum (P < 0.05). Diets containing FCSM also reduced pH and coliform population in the ileum, and ceca and increased lactic acid bacteria count in the crop and ceca (P < 0.05). Overall, the present data showed that including FCSM in the diet of laying hens can positively affect productive performance compared to CSM. Moreover, substituting SBM with FCSM, can improve eggshell quality, promote gut health, and reduce egg yolk cholesterol concentration.

The impact of different levels of functional oil supplementation in combination with salinomycin on growth performance and intestinal microbiota of broilers undergoing Eimeria challenge: An analysis of dynamics.

The effect of salinomycin sodium alone and in combination with functional oils on performance and microbiota of broiler infected Eimeria were evaluated. 512 broilers were randomly assigned to 4 treatments (8 replicates, 16 birds/pen): a Control group (any additives); Ionophore group: salinomycin supplementation at 66 ppm (SS66); Ionophore +0.075% Functional oil (FO) group (SS66 + FO supplementation at 750 ppm); and Ionophore +0.10% FO group (SS66 + FO supplementation at 1000 ppm). At 14 days of age, birds were gavaged with 1 mL of a saline solution containing sporulated oocysts of E. tenella, E. acervulina and E. maxima. Performance indices were measured weekly. At 28 days, intestinal content was collected for microbiota analysis. Broilers of Control group presented the worst performance indices. Broilers of Ionophore + FO (0.075% and 0.10%) groups exhibited a higher BW at 28 days of age. The supplementation of Ionophore +0.075% FO resulted in a higher relative proportion of Firmicutes and a lower proportion of Actinobacteria in the ileum-jejunum. Lactobacillaceae was the dominant family in the jejunal, and ileal microbiotas of broilers fed diets supplemented with Ionophore, Ionophore +0.075% FO and Ionophore +0.10% FO. The supplementation of ionophore yielded higher numbers of Lactobacillaceae, Enterobactereaceae and Cloritridiaceae in the cecal. Ionophore associated with FO controlled the Lactobacillaceae, Enterobactereaceae and Cloritridiaceae families present in the cecum. Therefore, the combination of salinomycin with functional oil showed synergistic effect on performance and modulation of intestinal microbiota of broilers challenged with Eimeria.

PKM2 promotes myoblast growth and inosine monophosphate-specific deposition in Jingyuan chicken.

Inosine monophosphate (IMP) is widely regarded as an important indicator for evaluating the flavour of poultry meat. However, little is known about the molecular mechanisms affecting the specific deposition of IMP. In this study, we functionally verified PKM2 (Pyruvate kinase M2), a candidate gene related to IMP synthesis, in order to reveal the important role of PKM2 in meat flavour and muscle development of Jingyuan chickens. The results showed that the IMP content in breast muscle of Jingyuan chickens was negatively correlated with PKM2 mRNA expression (r = -0.1710), while the IMP content in leg muscle was significantly positively correlated with PKM2 mRNA expression (r = 0.7350) (P < 0.05). During myogenesis, PKM2 promoted the proliferation rate of myoblasts and the expression of proliferation marker genes, inhibited the apoptosis rate and the expression of apoptosis marker genes, and decreased the expression of differentiation marker genes. Up-regulation of PKM2 enhanced the expression of key genes in the purine metabolic pathway and the de novo synthesis pathway of IMP, and suppressed the expression of key genes in the salvage pathway. ELISA assays showed that PKM2 decreased IMP and hypoxanthine (HX) contents, while adenosine triphosphate (ATP) and uric acid (UA) contents were clearly elevated. In summary, these studies revealed that PKM2 regulates myogenesis and specific deposition of IMP, which can be used to improve the quality of Jingyuan chicken meat.

Dietary guanidinoacetate reduces spaghetti meat myopathy risk in the breast muscle of broiler chickens.

The global demand for white chicken meat along with the increase in the occurrence of growth-related breast muscle myopathies (BMMs) [namely white striping (WS), wooden breast (WB), and spaghetti meat (SM)] highlights the need for solutions that will improve meat quality while maintaining the high productivity of modern broilers. Guanidinoacetate (GAA), a precursor of creatine, is used as a feed additive and has previously shown the potential to affect the quality of breast meat. This study investigated growth performance, meat quality and the risk ratio for the development of BMMs in broilers assigned to two dietary treatments: control (CON) group, fed a commercial basal diet, and supplemented GAA (sGAA) group, receiving the control diet supplemented on top with 0.06% GAA. Growth performance indicators such as BW, daily weight gain, daily feed intake, feed conversion ratio and cumulative feed conversion ratio were recorded on a pen basis. As a trait affecting animal welfare, the occurrence of foot pad dermatitis was also evaluated. At day 43, birds were processed, and breasts were scored for the incidence and severity of BMMs (n = 166 and 165 in CON and sGAA groups, respectively). Quality traits (ultimate pH, colour) and technological properties (i.e., drip and cooking losses, marinade uptake, shear force, and oxidation levels of the lipid and the protein fractions) of breast meat were assessed in both treatments on samples not showing any macroscopic sign of BMMs (n = 20 breast fillets per group). Data of myopathy risk ratio were analysed as the risk for each group to develop WS, WB, and SM myopathies. Our results show that while sGAA and control groups did not differ significantly in growth performance, a remarkably beneficial effect of GAA was observed on the incidence of BMMs with significantly reduced risk of sGAA group to develop SM myopathy. The risk of sGAA group to develop SM was 30% lower compared to CON (P = 0.028). Finally, a significantly lower drip loss was observed in sGAA in comparison with CON (1.78 vs 2.48%, P = 0.020). Together, our results show that the inclusion of 0.06% GAA in feed can improve the water-holding capacity of meat and reduce the risk to develop SM myopathy without compromising the performance of broilers.

Research Note: SOCS2 contributes to reduction of the third digit during development of the chicken forelimb.

The development of the avian wing pattern has been the subject of heated debate due to its special shape. The Suppressor of cytokine signaling 2 (SOCS2) gene encodes a negative regulator of growth hormone (GH) signaling and bone growth and is known to be strongly expressed in the third digit of chicken forelimbs. These observations suggest that SOCS2 might regulate the morphology of the avian wing, however, the function of SOCS2 in avian limb development remains unknown. Here, we reexamined SOCS2 expression in successive developmental stages of chicken limb development by in situ hybridization (ISH) and describe extended expression from the posterior of the stypolod to the third digit of the forelimbs. We used the RCAS avian retrovirus to overexpress SOCS2 in the developing chicken limb buds, which resulted in reduced or malformed chicken wings while hindlimbs developed normally. Transcriptome sequencing (mRNA-Seq) revealed changes in expression of genes known to be associated with growth and development in forelimbs with overexpressed SOCS2. This study highlights a pivotal role for SOCS2 during the development of the wing in the chicken and provides new insight into molecular mechanisms regulating avian limb development.

Carcass traits and meat quality assessment of two slow-growing chicks strains fed Acheta domesticus larval meal.

Presently, there has been a noticeable rise in the consumption of poultry meat within the general population, particularly focusing on poultry sourced from alternative rearing systems as opposed to intensive ones. This study evaluated the impact of incorporating house cricket (Acheta domesticus,AD) larvae meal into the diet of 2 slow-growing chicken strains on their carcass traits and meat quality. A total of 256 one-day-old male chicks were utilized, with 128 belonging to the Red (R) strain and 128 to the Naked Neck (NN) strain. Chicks from each strain were randomly assigned to 16 replicates of 8 chicks each. Eight replicates were allocated to 2 distinct treatments (n=64 chicks/treatment) based on the diet employed: the control treatments for the Red (R-C) and Naked Neck (NN-C) strains were fed soybean meal, while the other 2 treatments were fed AD meal (R-AD and NN-AD). Three different rations were used throughout the growth cycle of the animals, tailored to meet the nutritional needs of the birds. All chickens were slaughtered at 95 d of age, and eight chickens per treatment were randomly chosen to assess carcass traits and meat quality. Near-infrared reflectance spectroscopy (NIRS) was employed to classify meat based on the feed and the chick strain, achieving a correct discrimination of 100% of the samples. The carcass traits exhibited significant alterations due to the inclusion of insect larval meal in the diet, resulting in reduced values across all parameters for chickens consuming AD meal, irrespective of genotype. The pH and cooking losses were generally higher for chicks fed cricket meal, as occurred with moisture. However, protein content was lower in the meat of chicks consuming cricket meal. Fat content showed lower values for NN chickens. There were minimal differences in the fatty acid profile, with lower C18:3n-3 values for chickens fed cricket meal. Therefore, including Acheta domesticus meal in the diets of slow-growing chick strains is a viable alternative to replace soybean meal. It provides meat quality characteristics comparable to those obtained in conventional systems.

Effects of different levels of pistachio (Pistachia vera) green hull aqueous extract on performance, intestinal morphology and antioxidant capacity in Eimeria challenged broilers.

A total of 576-day-old Ross 308 broilers chicks (male) were used to evaluate the effect of various levels of pistachio green hull aqueous extract (PHE) and Eimeria challenge on the growth performance, intestinal health and antioxidant capacity. During infection period (25-42 d), treatments included: 1) control + unchallenged (negative control, NC), 2) 200 ppm PHE + unchallenged, 3) 300 ppm PHE + unchallenged, 4) 400 ppm PHE + unchallenged, 5) control + challenged (positive control, PC), 6) 200 ppm PHE + challenged, 7) 300 ppm PHE + challenged and 8) 400 ppm PHE + challenged (with 6 replications for each treatment). The outcomes revealed that in the challenged birds, average body weight gain (ABW), daily weight gain (DWG), and feed conversion ratio (FCR) linearly improved with increasing the PHE levels (P < 0.05). Infected broilers had lower daily feed intake (DFI) compared to unchallenged birds (P < 0.05). Villus height (VH), villus height to crypt depth (VH: CD) ratio and villus surface area (VSA) reduced linearly (P < 0.05), while muscle layer thickness (MT) increased linearly in challenged birds (P < 0.05). The consumption of the PHE significantly reduced the excreta oocytes and duodenum and jejunum lesion scores in Eimeria-challenged broilers (P < 0.05). By increasing the PHE levels, total antioxidant capacity (TAC) and superoxide dismutase (SOD) levels increased (P < 0.05), while the Eimeria challenge reduced TAC, SOD, and glutathione peroxidase (GPx) levels (P <0.05). In general, the use of PHE in the broilers diet improved the antioxidant capacity, birds performance, but diminished the excreta oocytes and lesion scores with no negative effect on the intestinal morphology.

The impact of dietary supplementation of polysaccharide derived from Polygonatum sibiricum on growth, antioxidant capacity, meat quality, digestive physiology, and gut microbiota in broiler chickens.

Polygonatum sibiricum polysaccharide (PSP) has demonstrated diverse medicinal properties, extensively researched for human applications. Nonetheless, there is a lack of studies investigating the potential advantages of PSP in poultry farming. The present study investigated the impact of incorporating PSP into broiler diets on their growth performance, meat quality, blood metabolites, antioxidative status, and ileal histomorphology. Two hundred and forty-one-day-old male Ross-308 broiler chicks (44.98 ± 0.79 g) were randomly assigned to 3 experimental groups, with 8 replicates of 10 birds each. The birds were fed diets supplemented with PSP at 0, 400, and 800 mg/kg (control, PSP400, and PSP800, respectively). The results revealed a linear (P > 0.05) improvement in body weight gain, European production efficiency index, and feed conversion ratio during the grower (22-35 d) and overall periods (1-35 d). The pH levels in the ingluvies, ileum, and cecum exhibited a linear reduction (P > 0.05) in the PSP800 group at d 21 and d 35, respectively. Villus height and crypt depth were increased in the PSP400 and PSP800 groups compared to the control group. PSP400 and PSP800 groups exhibited decreased hydrogen peroxide (H2O2) levels and increased total antioxidant capacity (TAC) at 21 d, while at 35 d, TAC and sulfhydryl concentrations were elevated, and H2O2 was reduced only in the PSP800 group compared to the untreated one. No significant variations between the groups at the phylum and genus levels were observed, with Bacteroidetes and Firmicutes being the dominant phyla. However, PSP supplementation notably augmented Firmicutes and Verrucomicrobiota while reducing Euryarchaeota and Proteobacteria. At the genus level, there was an increase in Akkermansia, Alistipes, CHKCI001, Erysipelatoclostridium, and a decrease in Methanobrevibacter. Conclusively, incorporating PSP into broiler diets, particularly at a dosage of 800 mg/kg, improved growth performance, antioxidant capacity, and intestinal architecture and resulted in alterations in cecal microbiota without discernible impacts on digestive function and meat quality criteria.

Investigating the impact of pigmentation variation of breast muscle on growth traits, melanin deposition, and gene expression in Xuefeng black-bone chickens.

The blackness traits, considered an important economic factor in the black-bone chicken industry, still exhibits a common phenomenon of significant difference in blackness of breast muscle. To improve this phenomenon, this study compared growth traits, blackness traits, and transcriptome of breast muscles between the High Blackness Group (H group) and Low Blackness Group (L group) in the Xuefeng black-bone chickens. The results are as follows: 1) There was no significant difference in growth traits between the H group and the L group (P > 0.05). 2) The skin/breast muscle L values in the H group were significantly lower than those in the L group, while the breast muscle melanin content exhibited the opposite trend (P < 0.05). 3) A significant negative correlation was observed between breast muscle melanin content and skin/breast muscle L value (P < 0.05), and skin L value exhibiting a significant positive correlation with breast muscle L value (P < 0.05). 4) The breast muscle transcriptome comparison between the H group and L group revealed 831 and 405 DEGs in female and male chickens, respectively. This included 37 shared DEGs significantly enriched in melanosome, pigment granule, and the melanogenesis pathway. Seven candidate genes (DCT, PMEL, MLANA, TYRP1, OCA2, EDNRB2, and CALML4) may play a crucial role in the melanin production of breast muscle in Xuefeng black-bone chicken. The findings could accelerate the breeding process for achieving desired levels of breast muscle blackness and contribute to the exploration of the mechanisms underlying melanin production in black-bone chickens.